Initial import

libc/sock/accept-nt.c

@@ -0,0 +1,53 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
+#include "libc/calls/internal.h"
+#include "libc/nt/files.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sysv/consts/fio.h"
+#include "libc/sysv/consts/sock.h"
+#include "libc/sysv/errfuns.h"
+
+textwindows int accept$nt(struct Fd *fd, void *addr, uint32_t *addrsize,
+                          int flags) {
+  int client;
+  uint32_t yes;
+  assert(fd->kind == kFdSocket);
+  if ((client = createfd()) == -1) return -1;
+  if ((g_fds.p[client].handle = WSAAccept(fd->handle, addr, (int32_t *)addrsize,
+                                          NULL, NULL)) != -1) {
+    if (flags & SOCK_CLOEXEC) {
+      SetHandleInformation(g_fds.p[client].handle, kNtHandleFlagInherit, 0);
+    }
+    if (flags & SOCK_NONBLOCK) {
+      yes = 1;
+      if (__ioctlsocket$nt(g_fds.p[client].handle, FIONBIO, &yes) == -1) {
+        __closesocket$nt(g_fds.p[client].handle);
+        return winsockerr();
+      }
+    }
+    g_fds.p[client].kind = kFdSocket;
+    g_fds.p[client].flags = flags;
+    return client;
+  } else {
+    return winsockerr();
+  }
+}

libc/sock/accept-sysv.c

@@ -0,0 +1,29 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+
+int accept$sysv(int server, void *addr, uint32_t *addrsize) {
+  int client;
+  if ((client = __accept$sysv(server, addr, addrsize)) != -1 && IsBsd()) {
+    sockaddr2linux(addr);
+  }
+  return client;
+}

libc/sock/accept.c

@@ -0,0 +1,43 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Creates client socket file descriptor for incoming connection.
+ *
+ * @param fd is the server socket file descriptor
+ * @param out_addr will receive the remote address
+ * @param inout_addrsize provides and receives addr's byte length
+ * @return client fd which needs close(), or -1 w/ errno
+ * @asyncsignalsafe
+ */
+int accept(int fd, void *out_addr, uint32_t *inout_addrsize) {
+  if (!IsWindows()) {
+    return accept$sysv(fd, out_addr, inout_addrsize);
+  } else if (isfdkind(fd, kFdSocket)) {
+    return accept$nt(&g_fds.p[fd], out_addr, inout_addrsize, 0);
+  } else {
+    return ebadf();
+  }
+}

libc/sock/accept4-sysv.c

@@ -0,0 +1,48 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dce.h"
+#include "libc/errno.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+
+#define __NR_accept4_linux 0x0120 /* rhel5:enosysevil */
+
+int accept4$sysv(int server, void *addr, uint32_t *addrsize, int flags) {
+  static bool once, demodernize;
+  int olderr, client;
+  if (!flags || demodernize) goto TriedAndTrue;
+  olderr = errno;
+  client = __accept4$sysv(server, addr, addrsize, flags);
+  if (client == -1 && errno == ENOSYS) {
+    errno = olderr;
+  TriedAndTrue:
+    client = fixupnewsockfd$sysv(__accept$sysv(server, addr, addrsize), flags);
+  } else if (SupportsLinux() && !once) {
+    once = true;
+    if (client == __NR_accept4_linux) {
+      demodernize = true;
+      goto TriedAndTrue;
+    }
+  }
+  if (client != -1 && IsBsd()) {
+    sockaddr2linux(addr);
+  }
+  return client;
+}

libc/sock/accept4.c

@@ -0,0 +1,44 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Creates client socket file descriptor for incoming connection.
+ *
+ * @param fd is the server socket file descriptor
+ * @param out_addr will receive the remote address
+ * @param inout_addrsize provides and receives out_addr's byte length
+ * @param flags can have SOCK_{CLOEXEC,NONBLOCK}, which may apply to
+ *     both the newly created socket and the server one
+ * @return client fd which needs close(), or -1 w/ errno
+ */
+int accept4(int fd, void *out_addr, uint32_t *inout_addrsize, int flags) {
+  if (!IsWindows()) {
+    return accept4$sysv(fd, out_addr, inout_addrsize, flags);
+  } else if (isfdkind(fd, kFdSocket)) {
+    return accept$nt(&g_fds.p[fd], out_addr, inout_addrsize, flags);
+  } else {
+    return ebadf();
+  }
+}

libc/sock/bind-nt.c

@@ -0,0 +1,43 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
+#include "libc/calls/internal.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Assigns local address and port number to socket.
+ *
+ * @param fd is the file descriptor returned by socket()
+ * @param addr is usually the binary-encoded ip:port on which to listen
+ * @param addrsize is the byte-length of addr's true polymorphic form
+ * @return socket file descriptor or -1 w/ errno
+ * @error ENETDOWN, EPFNOSUPPORT, etc.
+ * @asyncsignalsafe
+ */
+textwindows int bind$nt(struct Fd *fd, const void *addr, uint32_t addrsize) {
+  assert(fd->kind == kFdSocket);
+  if (__bind$nt(fd->handle, addr, addrsize) != -1) {
+    return 0;
+  } else {
+    return winsockerr();
+  }
+}

libc/sock/bind.c

@@ -0,0 +1,58 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/str/str.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Assigns local address and port number to socket.
+ *
+ * @param fd is the file descriptor returned by socket()
+ * @param addr is usually the binary-encoded ip:port on which to listen
+ * @param addrsize is the byte-length of addr's true polymorphic form
+ * @return socket file descriptor or -1 w/ errno
+ * @error ENETDOWN, EPFNOSUPPORT, etc.
+ * @asyncsignalsafe
+ */
+int bind(int fd, const void *addr, uint32_t addrsize) {
+  if (addrsize == sizeof(struct sockaddr_in)) {
+    if (!IsWindows()) {
+      if (!IsBsd()) {
+        return bind$sysv(fd, addr, addrsize);
+      } else {
+        struct sockaddr_in$bsd addr2;
+        static_assert(sizeof(struct sockaddr_in) ==
+                      sizeof(struct sockaddr_in$bsd));
+        memcpy(&addr2, addr, sizeof(struct sockaddr_in));
+        sockaddr2bsd(&addr2);
+        return bind$sysv(fd, &addr2, addrsize);
+      }
+    } else if (isfdkind(fd, kFdSocket)) {
+      return bind$nt(&g_fds.p[fd], addr, addrsize);
+    } else {
+      return ebadf();
+    }
+  } else {
+    return einval();
+  }
+}

libc/sock/closesocket-nt.c

@@ -0,0 +1,32 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/bits/safemacros.h"
+#include "libc/calls/internal.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sysv/errfuns.h"
+
+textwindows int closesocket$nt(int fd) {
+  int rc;
+  if (!isfdkind(fd, kFdSocket)) return ebadf();
+  rc = __closesocket$nt(g_fds.p[fd].handle) ? 0 : winsockerr();
+  removefd(fd);
+  return rc;
+}

libc/sock/connect-nt.c

@@ -0,0 +1,31 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
+#include "libc/calls/internal.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sysv/errfuns.h"
+
+textwindows int connect$nt(struct Fd *fd, const void *addr, uint32_t addrsize) {
+  assert(fd->kind == kFdSocket);
+  return winsockblock(
+      fd->handle, FD_CONNECT_BIT,
+      WSAConnect(fd->handle, addr, addrsize, NULL, NULL, NULL, NULL));
+}

libc/sock/connect-sysv.c

@@ -0,0 +1,36 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+#include "libc/str/str.h"
+#include "libc/sysv/errfuns.h"
+
+int connect$sysv(int fd, const void *addr, uint32_t addrsize) {
+  if (addrsize != sizeof(struct sockaddr_in)) return einval();
+  if (!IsBsd()) {
+    return __connect$sysv(fd, addr, addrsize);
+  } else {
+    struct sockaddr_in$bsd addr2;
+    static_assert(sizeof(struct sockaddr_in) == sizeof(struct sockaddr_in$bsd));
+    memcpy(&addr2, addr, sizeof(struct sockaddr_in));
+    sockaddr2bsd(&addr2);
+    return connect$sysv(fd, &addr2, addrsize);
+  }
+}

libc/sock/connect.c

@@ -0,0 +1,44 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Connects socket to remote end.
+ *
+ * ProTip: Connectionless sockets, e.g. UDP, can be connected too. The
+ * benefit is not needing to specify the remote address on each send. It
+ * also means getsockname() can be called to retrieve routing details.
+ *
+ * @return 0 on success or -1 w/ errno
+ * @asyncsignalsafe
+ */
+int connect(int fd, const void *addr, uint32_t addrsize) {
+  if (!IsWindows()) {
+    return connect$sysv(fd, addr, addrsize);
+  } else if (isfdkind(fd, kFdSocket)) {
+    return connect$nt(&g_fds.p[fd], addr, addrsize);
+  } else {
+    return ebadf();
+  }
+}

libc/sock/fixupnewsockfd.c

@@ -0,0 +1,35 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/calls/internal.h"
+#include "libc/sysv/consts/o.h"
+#include "libc/sysv/consts/sock.h"
+
+/**
+ * Applies non-atomic file descriptor fixups on XNU or ancient Linux.
+ *
+ * @param fd of -1 means no-op
+ */
+int fixupnewsockfd$sysv(int fd, int flags) {
+  return fixupnewfd$sysv(fd, (((flags & SOCK_CLOEXEC) ? O_CLOEXEC : 0) |
+                              ((flags & SOCK_NONBLOCK) ? O_NONBLOCK : 0)));
+}

libc/sock/getpeername-nt.c

@@ -0,0 +1,35 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sysv/errfuns.h"
+
+textwindows int getpeername$nt(struct Fd *fd, void *out_addr,
+                               uint32_t *out_addrsize) {
+  assert(fd->kind == kFdSocket);
+  if (__getpeername$nt(fd->handle, out_addr, out_addrsize) != -1) {
+    return 0;
+  } else {
+    return winsockerr();
+  }
+}

libc/sock/getpeername-sysv.c

@@ -0,0 +1,29 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+
+int getpeername$sysv(int fd, void *out_addr, uint32_t *out_addrsize) {
+  int rc = __getpeername$sysv(fd, out_addr, out_addrsize);
+  if (rc != -1 && IsBsd()) {
+    sockaddr2linux(out_addr);
+  }
+  return rc;
+}

libc/sock/getpeername.c

@@ -0,0 +1,39 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Returns details about remote end of connected socket.
+ * @return 0 on success or -1 w/ errno
+ * @see getsockname()
+ */
+int getpeername(int fd, void *out_addr, uint32_t *out_addrsize) {
+  if (!IsWindows()) {
+    return getpeername$sysv(fd, out_addr, out_addrsize);
+  } else if (isfdkind(fd, kFdSocket)) {
+    return getpeername$nt(&g_fds.p[fd], out_addr, out_addrsize);
+  } else {
+    return ebadf();
+  }
+}

libc/sock/getsockname-nt.c

@@ -0,0 +1,35 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sysv/errfuns.h"
+
+textwindows int getsockname$nt(struct Fd *fd, void *out_addr,
+                               uint32_t *out_addrsize) {
+  assert(fd->kind == kFdSocket);
+  if (__getsockname$nt(fd->handle, out_addr, out_addrsize) != -1) {
+    return 0;
+  } else {
+    return winsockerr();
+  }
+}

libc/sock/getsockname-sysv.c

@@ -0,0 +1,29 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+
+int getsockname$sysv(int fd, void *out_addr, uint32_t *out_addrsize) {
+  int rc = __getsockname$sysv(fd, out_addr, out_addrsize);
+  if (rc != -1 && IsBsd()) {
+    sockaddr2linux(out_addr);
+  }
+  return rc;
+}

libc/sock/getsockname.c

@@ -0,0 +1,39 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Returns details about network interface kernel granted socket.
+ * @return 0 on success or -1 w/ errno
+ * @see getpeername()
+ */
+int getsockname(int fd, void *out_addr, uint32_t *out_addrsize) {
+  if (!IsWindows()) {
+    return getsockname$sysv(fd, out_addr, out_addrsize);
+  } else if (isfdkind(fd, kFdSocket)) {
+    return getsockname$nt(&g_fds.p[fd], out_addr, out_addrsize);
+  } else {
+    return ebadf();
+  }
+}

libc/sock/getsockopt-nt.c

@@ -0,0 +1,36 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
+#include "libc/calls/internal.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sysv/errfuns.h"
+
+textwindows int getsockopt$nt(struct Fd *fd, int level, int optname,
+                              void *out_opt_optval, uint32_t *out_optlen) {
+  /* TODO(jart): Use WSAIoctl? */
+  assert(fd->kind == kFdSocket);
+  if (__getsockopt$nt(fd->handle, level, optname, out_opt_optval, out_optlen) !=
+      -1) {
+    return 0;
+  } else {
+    return winsockerr();
+  }
+}

libc/sock/getsockopt.c

@@ -0,0 +1,48 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Retrieves socket setting.
+ *
+ * @param level can be SOL_SOCKET, IPPROTO_TCP, etc.
+ * @param optname can be SO_{REUSE{PORT,ADDR},KEEPALIVE,etc.} etc.
+ * @return 0 on success, or -1 w/ errno
+ * @error ENOPROTOOPT for unknown (level,optname)
+ * @see libc/sysv/consts.sh for tuning catalogue
+ * @see setsockopt()
+ */
+int getsockopt(int fd, int level, int optname, void *out_opt_optval,
+               uint32_t *out_optlen) {
+  if (!level || !optname) return enoprotoopt(); /* our sysvconsts definition */
+  if (optname == -1) return 0;                  /* our sysvconsts definition */
+  if (!IsWindows()) {
+    return getsockopt$sysv(fd, level, optname, out_opt_optval, out_optlen);
+  } else if (isfdkind(fd, kFdSocket)) {
+    return getsockopt$nt(&g_fds.p[fd], level, optname, out_opt_optval,
+                         out_optlen);
+  } else {
+    return ebadf();
+  }
+}

libc/sock/inet_ntop.c

@@ -0,0 +1,53 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/fmt/fmt.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/errfuns.h"
+#include "libc/sysv/consts/af.h"
+
+/**
+ * Formats internet address to string.
+ *
+ * @param af can be AF_INET
+ * @param src is the binary-encoded address, e.g. &addr->sin_addr
+ * @param dst is the output string buffer
+ * @param size is bytes in dst, which needs 16+ for IPv4
+ * @return dst on success or NULL w/ errno
+ */
+const char *inet_ntop(int af, const void *src, char *dst, uint32_t size) {
+  if (src) {
+    if (af == AF_INET) {
+      unsigned char *p = (unsigned char *)src;
+      if (snprintf(dst, size, "%hhu.%hhu.%hhu.%hhu", p[0], p[1], p[2], p[3]) <
+          size) {
+        return dst;
+      } else {
+        enospc();
+      }
+    } else {
+      eafnosupport();
+    }
+  } else {
+    einval();
+  }
+  if (size) dst[0] = '\0';
+  return NULL;
+}

libc/sock/inet_pton.c

@@ -0,0 +1,48 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/fmt/fmt.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/errfuns.h"
+#include "libc/sysv/consts/af.h"
+#include "libc/sysv/consts/inaddr.h"
+
+/**
+ * Converts internet address string to binary.
+ *
+ * @param af can be AF_INET
+ * @param src is the ASCII-encoded address
+ * @param dst is where the binary-encoded net-order address goes
+ * @return 1 on success, 0 on src malformed, or -1 w/ errno
+ */
+int inet_pton(int af, const char *src, void *dst) {
+  if (af == AF_INET) {
+    unsigned char *p = (unsigned char *)dst;
+    if (sscanf(src, "%hhu.%hhu.%hhu.%hhu", &p[0], &p[1], &p[2], &p[3]) == 4) {
+      return 1;
+    } else {
+      *(uint32_t *)dst = htonl(INADDR_TESTNET3);
+      return 0;
+    }
+  } else {
+    *(uint32_t *)dst = htonl(INADDR_TESTNET3);
+    return eafnosupport();
+  }
+}

libc/sock/internal.h

@@ -0,0 +1,148 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=8 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#ifndef COSMOPOLITAN_LIBC_SOCK_INTERNAL_H_
+#define COSMOPOLITAN_LIBC_SOCK_INTERNAL_H_
+#include "libc/bits/bits.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/sock.h"
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+COSMOPOLITAN_C_START_
+
+#define FD_READ        (1 << FD_READ_BIT)
+#define FD_READ_BIT    0
+#define FD_WRITE       (1 << FD_WRITE_BIT)
+#define FD_WRITE_BIT   1
+#define FD_OOB         (1 << FD_OOB_BIT)
+#define FD_OOB_BIT     2
+#define FD_ACCEPT      (1 << FD_ACCEPT_BIT)
+#define FD_ACCEPT_BIT  3
+#define FD_CONNECT     (1 << FD_CONNECT_BIT)
+#define FD_CONNECT_BIT 4
+#define FD_CLOSE       (1 << FD_CLOSE_BIT)
+#define FD_CLOSE_BIT   5
+
+struct Fd;
+struct iovec;
+struct timeval;
+
+struct sockaddr$bsd {
+  uint8_t sa_len;    /* « different type */
+  uint8_t sa_family; /* « different type */
+  char sa_data[14];
+};
+
+struct sockaddr_in$bsd {
+  uint8_t sin_len;    /* « different type */
+  uint8_t sin_family; /* « different type */
+  uint16_t sin_port;
+  struct in_addr sin_addr;
+  uint8_t sin_zero[8];
+};
+
+struct msghdr$bsd {
+  void *msg_name;
+  uint32_t msg_namelen;
+  struct iovec *msg_iov;
+  uint32_t msg_iovlen; /* « different type */
+  void *msg_control;
+  uint64_t msg_controllen;
+  uint32_t msg_flags; /* « different type */
+};
+
+int32_t __accept$sysv(int32_t, void *, uint32_t *) nodiscard hidden;
+int32_t __accept4$sysv(int32_t, void *, uint32_t *, int) nodiscard hidden;
+int32_t __connect$sysv(int32_t, const void *, uint32_t) hidden;
+int32_t __socket$sysv(int32_t, int32_t, int32_t) hidden;
+int32_t __getsockname$sysv(int32_t, void *, uint32_t *) hidden;
+int32_t __getpeername$sysv(int32_t, void *, uint32_t *) hidden;
+
+int32_t select$sysv(int32_t, fd_set *, fd_set *, fd_set *, struct timeval *);
+int32_t setsockopt$sysv(int32_t, int32_t, int32_t, const void *,
+                        uint32_t) hidden;
+int32_t accept4$sysv(int32_t, void *, uint32_t *, int) nodiscard hidden;
+int32_t accept$sysv(int32_t, void *, uint32_t *) hidden;
+int32_t bind$sysv(int32_t, const void *, uint32_t) hidden;
+int32_t connect$sysv(int32_t, const void *, uint32_t) hidden;
+int32_t getsockopt$sysv(int32_t, int32_t, int32_t, void *, uint32_t *) hidden;
+int32_t listen$sysv(int32_t, int32_t) hidden;
+int32_t getsockname$sysv(int32_t, void *, uint32_t *) hidden;
+int32_t getpeername$sysv(int32_t, void *, uint32_t *) hidden;
+int32_t poll$sysv(struct pollfd *, uint64_t, signed) hidden;
+int32_t shutdown$sysv(int32_t, int32_t) hidden;
+int32_t socket$sysv(int32_t, int32_t, int32_t) hidden;
+int64_t readv$sysv(int32_t, const struct iovec *, int32_t) hidden;
+int64_t writev$sysv(int32_t, const struct iovec *, int32_t) hidden;
+ssize_t recvfrom$sysv(int, void *, size_t, int, void *, uint32_t *) hidden;
+ssize_t sendto$sysv(int, const void *, size_t, int, const void *,
+                    uint32_t) hidden;
+
+int poll$nt(struct pollfd *, uint64_t, int32_t) hidden;
+int getsockopt$nt(struct Fd *, int, int, void *, uint32_t *) hidden;
+int getsockname$nt(struct Fd *, void *, uint32_t *) hidden;
+int getpeername$nt(struct Fd *, void *, uint32_t *) hidden;
+int listen$nt(struct Fd *, int) hidden;
+int connect$nt(struct Fd *, const void *, uint32_t) hidden;
+int bind$nt(struct Fd *, const void *, uint32_t);
+int accept$nt(struct Fd *, void *, uint32_t *, int) hidden;
+int closesocket$nt(int) hidden;
+int socket$nt(int, int, int) hidden;
+
+size_t iovec2nt(struct iovec$nt[hasatleast 16], const struct iovec *,
+                size_t) hidden;
+ssize_t sendto$nt(struct Fd *, const struct iovec *, size_t, uint32_t, void *,
+                  uint32_t *) hidden;
+ssize_t recvfrom$nt(struct Fd *, const struct iovec *, size_t, uint32_t, void *,
+                    uint32_t *) hidden;
+
+int64_t winsockerr(void) nocallback hidden;
+int fixupnewsockfd$sysv(int, int) hidden;
+ssize_t WinSendRecv(int64_t, void *, size_t, uint32_t, struct sockaddr *,
+                    uint32_t *, bool) hidden;
+int64_t winsockblock(int64_t, unsigned, int64_t) hidden;
+
+/**
+ * Converts sockaddr (Linux/Windows) → sockaddr$bsd (XNU/BSD).
+ */
+forceinline void sockaddr2bsd(void *saddr) {
+  uint8_t *p;
+  uint16_t fam;
+  if (saddr) {
+    p = saddr;
+    fam = read16le(p);
+    p[0] = sizeof(struct sockaddr_in$bsd);
+    p[1] = fam;
+  }
+}
+
+/**
+ * Converts sockaddr_in$bsd (XNU/BSD) → sockaddr (Linux/Windows).
+ */
+forceinline void sockaddr2linux(void *saddr) {
+  uint8_t *p, fam;
+  if (saddr) {
+    p = saddr;
+    fam = p[1];
+    WRITE16LE(p, fam);
+  }
+}
+
+COSMOPOLITAN_C_END_
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* COSMOPOLITAN_LIBC_SOCK_INTERNAL_H_ */

libc/sock/iovec2nt.c

@@ -0,0 +1,45 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
+#include "libc/calls/struct/iovec.h"
+#include "libc/macros.h"
+#include "libc/sock/internal.h"
+#include "libc/sysv/consts/iov.h"
+
+/**
+ * Converts I/O vector from System Five to WIN32 ABI.
+ *
+ * @return effective iovlen
+ * @see IOV_MAX
+ */
+textwindows size_t iovec2nt(struct iovec$nt iovnt[hasatleast 16],
+                            const struct iovec *iov, size_t iovlen) {
+  size_t i, limit;
+  for (limit = 0x7ffff000, i = 0; i < MIN(16, iovlen); ++i) {
+    iovnt[i].buf = iov[i].iov_base;
+    if (iov[i].iov_len < limit) {
+      limit -= (iovnt[i].len = iov[i].iov_len);
+    } else {
+      iovnt[i].len = limit;
+      break;
+    }
+  }
+  return i;
+}

libc/sock/ipclassify.h

@@ -0,0 +1,68 @@
+#ifndef COSMOPOLITAN_LIBC_SOCK_IPCLASSIFY_H_
+#define COSMOPOLITAN_LIBC_SOCK_IPCLASSIFY_H_
+#include "libc/sock/sock.h"
+#include "libc/sysv/errfuns.h"
+#include "libc/sysv/consts/af.h"
+#include "libc/sysv/consts/inaddr.h"
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+COSMOPOLITAN_C_START_
+
+/**
+ * Returns true if address is part of standardized test-only subnet.
+ */
+forceinline bool istestip(int sin_family, void *sin_addr) {
+  if (sin_family == AF_INET) {
+    uint32_t ip4net24 = ntohl(*(const uint32_t *)sin_addr) & 0xffffff00u;
+    if (ip4net24 == INADDR_TESTNET1 || ip4net24 == INADDR_TESTNET2 ||
+        ip4net24 == INADDR_TESTNET3) {
+      return true;
+    }
+  } else {
+    eafnosupport();
+  }
+  return false;
+}
+
+/**
+ * Returns true if address is part of a local-only subnet.
+ */
+forceinline bool islocalip(int sin_family, void *sin_addr) {
+  if (sin_family == AF_INET) {
+    uint32_t ip4net8 = ntohl(*(const uint32_t *)sin_addr) & 0xff000000u;
+    if (ip4net8 == 0x7f000000u) {
+      return true;
+    }
+  } else {
+    eafnosupport();
+  }
+  return false;
+}
+
+/**
+ * Returns true if address is part of a well-known private subnet.
+ */
+forceinline bool isprivateip(int sin_family, void *sin_addr) {
+  if (sin_family == AF_INET) {
+    uint32_t ip4 = ntohl(*(const uint32_t *)sin_addr);
+    if ((0x0a000000u <= ip4 && ip4 <= 0x0affffffu) /* 10.0.0.0/8     */ ||
+        (0xac100000u <= ip4 && ip4 <= 0xac1fffffu) /* 172.16.0.0/12  */ ||
+        (0xc0a80000u <= ip4 && ip4 <= 0xc0a8ffffu) /* 192.168.0.0/16 */) {
+      return true;
+    }
+  } else {
+    eafnosupport();
+  }
+  return false;
+}
+
+/**
+ * Returns true if address is most likely part of the public Internet.
+ */
+forceinline bool ispublicip(int sin_family, void *sin_addr) {
+  return !islocalip(sin_family, sin_addr) &&
+         !isprivateip(sin_family, sin_addr) && !istestip(sin_family, sin_addr);
+}
+
+COSMOPOLITAN_C_END_
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* COSMOPOLITAN_LIBC_SOCK_IPCLASSIFY_H_ */

libc/sock/kntwsadata.c

@@ -0,0 +1,47 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dce.h"
+#include "libc/nt/winsock.h"
+#include "libc/runtime/runtime.h"
+#include "libc/sock/internal.h"
+
+#define VERSION 0x0202 /* Windows Vista+ */
+
+/**
+ * Information about underyling Windows Sockets implemmentation.
+ *
+ * Cosmopolitan automatically calls YOINK() on this symbol when its
+ * Berkeley Socket wrappers are linked. The latest version of Winsock
+ * was introduced alongside x64, so this should never fail.
+ */
+struct NtWsaData kNtWsaData;
+
+textwindows static void winsockfini(void) { WSACleanup(); }
+textstartup static void winsockinit(void) {
+  if (!IsWindows()) return;
+  atexit(winsockfini);
+  int rc;
+  if ((rc = WSAStartup(VERSION, &kNtWsaData)) != 0 ||
+      kNtWsaData.wVersion != VERSION) {
+    abort();
+  }
+}
+
+const void *const winsockctor[] initarray = {winsockinit};

libc/sock/listen-nt.c

@@ -0,0 +1,33 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
+#include "libc/calls/internal.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sysv/errfuns.h"
+
+textwindows int listen$nt(struct Fd *fd, int backlog) {
+  assert(fd->kind == kFdSocket);
+  if (__listen$nt(fd->handle, backlog) != -1) {
+    return 0;
+  } else {
+    return winsockerr();
+  }
+}

libc/sock/listen.c

@@ -0,0 +1,45 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Asks system to accept incoming connections on socket.
+ *
+ * The socket() and bind() functions need to be called beforehand. Once
+ * this function is called, accept() is used to wait for connections.
+ * Using this on connectionless sockets will allow it to receive packets
+ * on a designated address.
+ *
+ * @param backlog <= SOMAXCONN
+ * @return 0 on success or -1 w/ errno
+ */
+int listen(int fd, int backlog) {
+  if (!IsWindows()) {
+    return listen$sysv(fd, backlog);
+  } else if (isfdkind(fd, kFdSocket)) {
+    return listen$nt(&g_fds.p[fd], backlog);
+  } else {
+    return ebadf();
+  }
+}

libc/sock/parseport.c

@@ -0,0 +1,27 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/conv/conv.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/errfuns.h"
+
+int parseport(const char *service) {
+  int port = atoi(service);
+  return (0 <= port && port <= 65535) ? port : einval();
+}

libc/sock/poll-nt.c

@@ -0,0 +1,45 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/nt/struct/pollfd.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sysv/consts/poll.h"
+#include "libc/sysv/errfuns.h"
+
+textwindows int poll$nt(struct pollfd *fds, uint64_t nfds, int32_t timeout_ms) {
+  int got;
+  size_t i;
+  struct pollfd$nt ntfds[64];
+  if (nfds > 64) return einval();
+  for (i = 0; i < nfds; ++i) {
+    if (!isfdkind(fds[i].fd, kFdSocket)) return ebadf();
+    ntfds[i].handle = g_fds.p[fds[i].fd].handle;
+    ntfds[i].events = fds[i].events & (POLLPRI | POLLIN | POLLOUT);
+  }
+  if ((got = WSAPoll(ntfds, nfds, timeout_ms)) != -1) {
+    for (i = 0; i < nfds; ++i) {
+      fds[i].revents = ntfds[i].revents;
+    }
+    return got;
+  } else {
+    return winsockerr();
+  }
+}

libc/sock/poll.c

@@ -0,0 +1,46 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+
+/**
+ * Waits for something to happen on multiple file descriptors at once.
+ *
+ * @param fds[𝑖].fd should have been created with SOCK_NONBLOCK passed
+ *     to socket() or accept4()
+ * @param fds[𝑖].events flags can have POLL{IN,OUT,PRI}
+ * @param timeout_ms if 0 means don't wait and -1 means wait forever
+ * @return number of items fds whose revents field has been set to
+ *     nonzero to describe its events, or -1 w/ errno
+ * @return fds[𝑖].revents flags can have:
+ *     (fds[𝑖].events & POLL{IN,OUT,PRI,HUP,ERR,NVAL})
+ * @asyncsignalsafe
+ * @see ppoll()
+ */
+int poll(struct pollfd *fds, uint64_t nfds, int32_t timeout_ms) {
+  if (!IsWindows()) {
+    return poll$sysv(fds, nfds, timeout_ms);
+  } else {
+    return poll$nt(fds, nfds, timeout_ms);
+  }
+}

libc/sock/recv.c

@@ -0,0 +1,36 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/sock/sock.h"
+
+/**
+ * Receives data from network socket.
+ *
+ * @param fd is the file descriptor returned by socket()
+ * @param buf is where received network data gets copied
+ * @param size is the byte capacity of buf
+ * @param flags can have MSG_{WAITALL,PEEK,OOB}, etc.
+ * @return number of bytes received, 0 on remote close, or -1 w/ errno
+ * @error EINTR, EHOSTUNREACH, ECONNRESET (UDP ICMP Port Unreachable),
+ *     EPIPE (if MSG_NOSIGNAL), EMSGSIZE, ENOTSOCK, EFAULT, etc.
+ * @asyncsignalsafe
+ */
+ssize_t recv(int fd, void *buf, size_t size, int flags) {
+  return recvfrom(fd, buf, size, flags, NULL, 0);
+}

libc/sock/recvfrom-nt.c

@@ -0,0 +1,43 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
+#include "libc/calls/internal.h"
+#include "libc/sock/internal.h"
+
+/**
+ * Performs recv(), recvfrom(), or readv() on Windows NT.
+ *
+ * @param fd must be a socket
+ * @return number of bytes received, or -1 w/ errno
+ */
+textwindows ssize_t recvfrom$nt(struct Fd *fd, const struct iovec *iov,
+                                size_t iovlen, uint32_t flags,
+                                void *opt_out_srcaddr,
+                                uint32_t *opt_inout_srcaddrsize) {
+  uint32_t got;
+  struct iovec$nt iovnt[16];
+  got = 0;
+  if (WSARecvFrom(fd->handle, iovnt, iovec2nt(iovnt, iov, iovlen), &got, &flags,
+                  opt_out_srcaddr, opt_inout_srcaddrsize, NULL, NULL) != -1) {
+    return got;
+  } else {
+    return winsockerr();
+  }
+}

libc/sock/recvfrom.c

@@ -0,0 +1,60 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/calls/struct/iovec.h"
+#include "libc/dce.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Receives data from network.
+ *
+ * This function blocks unless MSG_DONTWAIT is passed.
+ *
+ * @param fd is the file descriptor returned by socket()
+ * @param buf is where received network data gets copied
+ * @param size is the byte capacity of buf
+ * @param flags can have MSG_{WAITALL,DONTROUTE,PEEK,OOB}, etc.
+ * @param opt_out_srcaddr receives the binary ip:port of the data's origin
+ * @param opt_inout_srcaddrsize is srcaddr capacity which gets updated
+ * @return number of bytes received, 0 on remote close, or -1 w/ errno
+ * @error EINTR, EHOSTUNREACH, ECONNRESET (UDP ICMP Port Unreachable),
+ *     EPIPE (if MSG_NOSIGNAL), EMSGSIZE, ENOTSOCK, EFAULT, etc.
+ * @asyncsignalsafe
+ */
+ssize_t recvfrom(int fd, void *buf, size_t size, uint32_t flags,
+                 void *opt_out_srcaddr, uint32_t *opt_inout_srcaddrsize) {
+  ssize_t got;
+  if (!IsWindows()) {
+    got = recvfrom$sysv(fd, buf, size, flags, opt_out_srcaddr,
+                        opt_inout_srcaddrsize);
+    if (opt_out_srcaddr && IsBsd() && got != -1) {
+      sockaddr2linux(opt_out_srcaddr);
+    }
+    return got;
+  } else if (isfdkind(fd, kFdSocket)) {
+    return recvfrom$nt(&g_fds.p[fd], (struct iovec[]){{buf, size}}, 1, flags,
+                       opt_out_srcaddr, opt_inout_srcaddrsize);
+  } else {
+    return ebadf();
+  }
+}

libc/sock/select.c

@@ -0,0 +1,28 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/struct/timeval.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+
+int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
+           struct timeval *timeout) {
+  /* TODO(jart): Windows */
+  return select$sysv(nfds, readfds, writefds, exceptfds, timeout);
+}

libc/sock/send.c

@@ -0,0 +1,36 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/sock/sock.h"
+
+/**
+ * Sends data to network socket.
+ *
+ * @param fd is the file descriptor returned by socket()
+ * @param buf is the data to send, which we'll copy if necessary
+ * @param size is the byte-length of buf
+ * @param flags MSG_OOB, MSG_DONTROUTE, MSG_PARTIAL, MSG_NOSIGNAL, etc.
+ * @return number of bytes transmitted, or -1 w/ errno
+ * @error EINTR, EHOSTUNREACH, ECONNRESET (UDP ICMP Port Unreachable),
+ *     EPIPE (if MSG_NOSIGNAL), EMSGSIZE, ENOTSOCK, EFAULT, etc.
+ * @asyncsignalsafe
+ */
+ssize_t send(int fd, const void *buf, size_t size, int flags) {
+  return sendto(fd, buf, size, flags, NULL, 0);
+}

libc/sock/sendfile.c

@@ -0,0 +1,101 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/bits/safemacros.h"
+#include "libc/calls/calls.h"
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/str/str.h"
+#include "libc/sysv/errfuns.h"
+
+static textwindows ssize_t sendfile$linux2nt(int outfd, int infd,
+                                             int64_t *inout_opt_inoffset,
+                                             size_t uptobytes) {
+  struct NtOverlapped Overlapped;
+  struct NtOverlapped *lpOverlapped;
+  if (!isfdkind(outfd, kFdSocket) || !isfdkind(outfd, kFdFile)) return ebadf();
+  if (inout_opt_inoffset) {
+    memset(&Overlapped, 0, sizeof(Overlapped));
+    Overlapped.Pointer = (void *)(intptr_t)(*inout_opt_inoffset);
+    lpOverlapped = &Overlapped;
+  } else {
+    lpOverlapped = NULL;
+  }
+  /* TODO(jart): Fetch this on a per-socket basis via GUID. */
+  if (TransmitFile(g_fds.p[outfd].handle, g_fds.p[infd].handle, uptobytes, 0,
+                   lpOverlapped, NULL, 0)) {
+    return uptobytes;
+  } else {
+    return winsockerr();
+  }
+}
+
+static ssize_t sendfile$linux2netflix(int outfd, int infd,
+                                      int64_t *inout_opt_inoffset,
+                                      size_t uptobytes) {
+  int sendfile$netflix(int32_t infd, int32_t outfd, int64_t offset,
+                       size_t nbytes, const void *opt_hdtr,
+                       int64_t *out_opt_sbytes,
+                       int32_t flags) asm("sendfile$sysv") hidden;
+  int rc;
+  int64_t offset, sbytes;
+  if (inout_opt_inoffset) {
+    offset = *inout_opt_inoffset;
+  } else if ((offset = lseek$sysv(infd, 0, SEEK_CUR)) == -1) {
+    return -1;
+  }
+  if ((rc = sendfile$netflix(infd, outfd, offset, uptobytes, NULL, &sbytes,
+                             0)) != -1) {
+    if (inout_opt_inoffset) *inout_opt_inoffset += sbytes;
+    return sbytes;
+  } else {
+    return -1;
+  }
+}
+
+/**
+ * Transfers data from file to network.
+ *
+ * @param outfd needs to be a socket
+ * @param infd needs to be a file
+ * @param inout_opt_inoffset may be specified for pread()-like behavior
+ * @param uptobytes is usually the number of bytes remaining in file; it
+ *     can't exceed INT_MAX-1; some platforms block until everything's
+ *     sent, whereas others won't; zero isn't allowed
+ * @return number of bytes transmitted which may be fewer than requested
+ * @see copy_file_range() for file ↔ file
+ * @see splice() for fd ↔ pipe
+ */
+ssize_t sendfile(int outfd, int infd, int64_t *inout_opt_inoffset,
+                 size_t uptobytes) {
+  if (!uptobytes) return einval();
+  if (uptobytes > 0x7ffffffe /* Microsoft's off-by-one */) return eoverflow();
+  if (IsModeDbg() && uptobytes > 1) uptobytes >>= 1;
+  if (IsLinux()) {
+    return sendfile$sysv(outfd, infd, inout_opt_inoffset, uptobytes);
+  } else if (IsFreebsd() || IsXnu()) {
+    return sendfile$linux2netflix(outfd, infd, inout_opt_inoffset, uptobytes);
+  } else if (IsWindows()) {
+    return sendfile$linux2nt(outfd, infd, inout_opt_inoffset, uptobytes);
+  } else {
+    return copyfd(infd, inout_opt_inoffset, outfd, NULL, uptobytes, 0);
+  }
+}

libc/sock/sendto-nt.c

@@ -0,0 +1,41 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
+#include "libc/calls/internal.h"
+#include "libc/sock/internal.h"
+
+/**
+ * Performs send(), sendto(), or writev() on Windows NT.
+ *
+ * @param fd must be a socket
+ * @return number of bytes handed off, or -1 w/ errno
+ */
+textwindows ssize_t sendto$nt(struct Fd *fd, const struct iovec *iov,
+                              size_t iovlen, uint32_t flags, void *opt_in_addr,
+                              uint32_t *in_addrsize) {
+  uint32_t sent;
+  struct iovec$nt iovnt[16];
+  if (WSASendTo(fd->handle, iovnt, iovec2nt(iovnt, iov, iovlen), &sent, flags,
+                opt_in_addr, *in_addrsize, NULL, NULL) != -1) {
+    return sent;
+  } else {
+    return winsockerr();
+  }
+}

libc/sock/sendto.c

@@ -0,0 +1,67 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/calls/struct/iovec.h"
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/str/str.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Sends data over network.
+ *
+ * This function blocks unless MSG_DONTWAIT is passed. In that case, the
+ * non-error EWOULDBLOCK might be returned. It basically means we didn't
+ * wait around to learn an amount of bytes were written that we know in
+ * advance are guaranteed to be atomic.
+ *
+ * @param fd is the file descriptor returned by socket()
+ * @param buf is the data to send, which we'll copy if necessary
+ * @param size is the byte-length of buf
+ * @param flags MSG_OOB, MSG_DONTROUTE, MSG_PARTIAL, MSG_NOSIGNAL, etc.
+ * @param opt_addr is a binary ip:port destination override, which is
+ *     mandatory for UDP if connect() wasn't called
+ * @param addrsize is the byte-length of addr's true polymorphic form
+ * @return number of bytes transmitted, or -1 w/ errno
+ * @error EINTR, EHOSTUNREACH, ECONNRESET (UDP ICMP Port Unreachable),
+ *     EPIPE (if MSG_NOSIGNAL), EMSGSIZE, ENOTSOCK, EFAULT, etc.
+ * @asyncsignalsafe
+ */
+ssize_t sendto(int fd, const void *buf, size_t size, uint32_t flags,
+               const void *opt_addr, uint32_t addrsize) {
+  static_assert(sizeof(struct sockaddr_in) == sizeof(struct sockaddr_in$bsd));
+  if (!IsWindows()) {
+    if (!IsBsd() || !opt_addr) {
+      return sendto$sysv(fd, buf, size, flags, opt_addr, addrsize);
+    } else {
+      struct sockaddr_in$bsd addr2;
+      if (addrsize != sizeof(addr2)) return einval();
+      memcpy(&addr2, opt_addr, sizeof(struct sockaddr_in));
+      sockaddr2bsd(&addr2);
+      return sendto$sysv(fd, buf, size, flags, &addr2, addrsize);
+    }
+  } else if (isfdkind(fd, kFdSocket)) {
+    return sendto$nt(&g_fds.p[fd], (struct iovec[]){{buf, size}}, 1, flags,
+                     opt_addr, &addrsize);
+  } else {
+    return ebadf();
+  }
+}

libc/sock/setsockopt.c

@@ -0,0 +1,77 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/errno.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/consts/so.h"
+#include "libc/sysv/errfuns.h"
+
+static bool setsockopt_polyfill(int *optname) {
+  if (errno == ENOPROTOOPT && *optname == SO_REUSEPORT /* RHEL5 */) {
+    *optname = SO_REUSEADDR; /* close enough */
+    return true;             /* fudges errno */
+  }
+  return false;
+}
+
+static textwindows int setsockopt$nt(struct Fd *fd, int level, int optname,
+                                     const void *optval, uint32_t optlen) {
+  if (__setsockopt$nt(fd->handle, level, optname, optval, optlen) != -1) {
+    return 0;
+  } else {
+    return winsockerr();
+  }
+}
+
+/**
+ * Modifies socket settings.
+ *
+ * This function is the ultimate rabbit hole. Basic usage:
+ *
+ *   int yes = 1;
+ *   setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &yes, sizeof(yes));
+ *
+ * @param level can be SOL_SOCKET, IPPROTO_TCP, etc.
+ * @param optname can be SO_{REUSE{PORT,ADDR},KEEPALIVE,etc.} etc.
+ * @return 0 on success, or -1 w/ errno
+ * @error ENOPROTOOPT for unknown (level,optname)
+ * @see libc/sysv/consts.sh for tuning catalogue
+ * @see getsockopt()
+ */
+int setsockopt(int fd, int level, int optname, const void *optval,
+               uint32_t optlen) {
+  if (!level || !optname) return enoprotoopt(); /* our sysvconsts definition */
+  if (optname == -1) return 0;                  /* our sysvconsts definition */
+  if (!IsWindows()) {
+    do {
+      if (setsockopt$sysv(fd, level, optname, optval, optlen) != -1) {
+        return 0;
+      }
+    } while (setsockopt_polyfill(&optname));
+    return -1;
+  } else if (isfdkind(fd, kFdSocket)) {
+    return setsockopt$nt(&g_fds.p[fd], level, optname, optval, optlen);
+  } else {
+    return ebadf();
+  }
+}

libc/sock/shutdown.c

@@ -0,0 +1,56 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/dce.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/errfuns.h"
+
+static int shutdown$nt(struct Fd *fd, int how) {
+  if (__shutdown$nt(fd->handle, how) != -1) {
+    return 0;
+  } else {
+    return winsockerr();
+  }
+}
+
+/**
+ * Disables sends or receives on a socket, without closing.
+ *
+ * @param fd is the open file descriptor for the socket
+ * @param how can be SHUT_RD, SHUT_WR, or SHUT_RDWR
+ * @return 0 on success or -1 on error
+ * @asyncsignalsafe
+ */
+int shutdown(int fd, int how) {
+  if (!IsWindows()) {
+    if (!IsXnu()) {
+      return shutdown$sysv(fd, how);
+    } else {
+      /* TODO(jart): What's wrong with XNU shutdown()? */
+      return 0;
+    }
+  } else if (isfdkind(fd, kFdSocket)) {
+    return shutdown$nt(&g_fds.p[fd], how);
+  } else {
+    return ebadf();
+  }
+}

libc/sock/sock.h

@@ -0,0 +1,99 @@
+#ifndef COSMOPOLITAN_LIBC_SOCK_SOCK_H_
+#define COSMOPOLITAN_LIBC_SOCK_SOCK_H_
+#include "libc/bits/bits.h"
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+COSMOPOLITAN_C_START_
+/*───────────────────────────────────────────────────────────────────────────│─╗
+│ cosmopolitan § system api » berkeley sockets                             ─╬─│┼
+╚────────────────────────────────────────────────────────────────────────────│*/
+
+#define INET_ADDRSTRLEN 22
+
+#define NI_DGRAM   0x10
+#define NI_MAXSERV 0x20
+
+#define htons(u16) bswap_16(u16)
+#define ntohs(u16) bswap_16(u16)
+#define htonl(u32) bswap_32(u32)
+#define ntohl(u32) bswap_32(u32)
+
+struct iovec;
+struct sigset;
+struct timespec;
+struct timeval;
+struct addrinfo;
+
+struct in_addr { /* ARPA ABI */
+  /* e.g. 127|0<<8|0<<16|1<<24 or inet_pton(AF_INET, "127.0.0.1", &s_addr) */
+  uint32_t s_addr;
+};
+
+struct sockaddr {     /* Linux+NT ABI */
+  uint16_t sa_family; /* AF_XXX */
+  char sa_data[14];
+};
+
+struct sockaddr_in {   /* Linux+NT ABI */
+  uint16_t sin_family; /* AF_XXX */
+  uint16_t sin_port;   /* htons(XXX) i.e. big endian */
+  struct in_addr sin_addr;
+  uint8_t sin_zero[8];
+};
+
+struct pollfd {
+  int32_t fd;
+  int16_t events;
+  int16_t revents;
+};
+
+struct msghdr {            /* Linux+NT ABI */
+  void *msg_name;          /* optional address */
+  int32_t msg_namelen;     /* size of msg_name */
+  struct iovec *msg_iov;   /* scatter/gather array */
+  uint64_t msg_iovlen;     /* iovec count */
+  void *msg_control;       /* credentials and stuff */
+  uint64_t msg_controllen; /* size of msg_control */
+  uint32_t msg_flags;      /* MSG_XXX */
+};
+
+const char *inet_ntop(int, const void *, char *, uint32_t);
+int inet_pton(int af, const char *, void *);
+int parseport(const char *);
+
+int socket(int, int, int) nodiscard;
+int accept(int, void *, uint32_t *) paramsnonnull() nodiscard;
+int accept4(int, void *, uint32_t *, int) paramsnonnull() nodiscard;
+int bind(int, const void *, uint32_t) paramsnonnull();
+int connect(int, const void *, uint32_t) paramsnonnull();
+int socketconnect(const struct addrinfo *, int);
+int listen(int, int);
+int shutdown(int, int);
+int getsockname(int, void *, uint32_t *) paramsnonnull();
+int getpeername(int, void *, uint32_t *) paramsnonnull();
+ssize_t send(int, const void *, size_t, int) paramsnonnull();
+ssize_t recv(int, void *, size_t, int);
+ssize_t recvmsg(int, struct msghdr *, uint32_t) paramsnonnull();
+ssize_t recvfrom(int, void *, size_t, uint32_t, void *, uint32_t *);
+ssize_t sendmsg(int, const struct msghdr *, int) paramsnonnull();
+ssize_t readv(int, const struct iovec *, int);
+ssize_t writev(int, const struct iovec *, int);
+ssize_t sendfile(int, int, int64_t *, size_t);
+int getsockopt(int, int, int, void *, uint32_t *) paramsnonnull((5));
+int setsockopt(int, int, int, const void *, uint32_t) paramsnonnull();
+int socketpair(int, int, int, int64_t[2]) paramsnonnull();
+int poll(struct pollfd *, uint64_t, int32_t) paramsnonnull();
+int ppoll(struct pollfd *, uint64_t, const struct timespec *,
+          const struct sigset *) paramsnonnull((1, 4));
+ssize_t sendto(int, const void *, size_t, uint32_t, const void *, uint32_t)
+    paramsnonnull((2));
+
+typedef int64_t fd_set;
+#define FD_CLR(FD, SET)   btr(SET, FD)
+#define FD_ISSET(FD, SET) bt(SET, FD)
+#define FD_SET(FD, SET)   bts(SET, FD)
+#define FD_ZERO(SET)      *(SET) = 0
+int select(int, fd_set *, fd_set *, fd_set *, struct timeval *);
+
+COSMOPOLITAN_C_END_
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* COSMOPOLITAN_LIBC_SOCK_SOCK_H_ */

libc/sock/sock.mk

@@ -0,0 +1,55 @@
+#-*-mode:makefile-gmake;indent-tabs-mode:t;tab-width:8;coding:utf-8-*-┐
+#───vi: set et ft=make ts=8 tw=8 fenc=utf-8 :vi───────────────────────┘
+
+PKGS += LIBC_SOCK
+
+LIBC_SOCK_ARTIFACTS += LIBC_SOCK_A
+LIBC_SOCK = $(LIBC_SOCK_A_DEPS) $(LIBC_SOCK_A)
+LIBC_SOCK_A = o/$(MODE)/libc/sock/sock.a
+LIBC_SOCK_A_FILES := $(wildcard libc/sock/*)
+LIBC_SOCK_A_HDRS = $(filter %.h,$(LIBC_SOCK_A_FILES))
+LIBC_SOCK_A_SRCS = $(filter %.c,$(LIBC_SOCK_A_FILES))
+
+LIBC_SOCK_A_OBJS =				\
+	$(LIBC_SOCK_A_SRCS:%=o/$(MODE)/%.zip.o)	\
+	$(LIBC_SOCK_A_SRCS:%.c=o/$(MODE)/%.o)
+
+LIBC_SOCK_A_CHECKS =				\
+	$(LIBC_SOCK_A).pkg			\
+	$(LIBC_SOCK_A_HDRS:%=o/$(MODE)/%.ok)
+
+LIBC_SOCK_A_DIRECTDEPS =			\
+	LIBC_CALLS				\
+	LIBC_CONV				\
+	LIBC_FMT				\
+	LIBC_MEM				\
+	LIBC_RUNTIME				\
+	LIBC_STDIO				\
+	LIBC_STUBS				\
+	LIBC_NT_KERNELBASE			\
+	LIBC_NT_WS2_32				\
+	LIBC_NT_MSWSOCK				\
+	LIBC_NEXGEN32E				\
+	LIBC_SYSV_CALLS				\
+	LIBC_SYSV
+
+LIBC_SOCK_A_DEPS :=				\
+	$(call uniq,$(foreach x,$(LIBC_SOCK_A_DIRECTDEPS),$($(x))))
+
+$(LIBC_SOCK_A):	libc/sock/			\
+		$(LIBC_SOCK_A).pkg		\
+		$(LIBC_SOCK_A_OBJS)
+
+$(LIBC_SOCK_A).pkg:				\
+		$(LIBC_SOCK_A_OBJS)		\
+		$(foreach x,$(LIBC_SOCK_A_DIRECTDEPS),$($(x)_A).pkg)
+
+LIBC_SOCK_LIBS = $(foreach x,$(LIBC_SOCK_ARTIFACTS),$($(x)))
+LIBC_SOCK_SRCS = $(foreach x,$(LIBC_SOCK_ARTIFACTS),$($(x)_SRCS))
+LIBC_SOCK_HDRS = $(foreach x,$(LIBC_SOCK_ARTIFACTS),$($(x)_HDRS))
+LIBC_SOCK_CHECKS = $(foreach x,$(LIBC_SOCK_ARTIFACTS),$($(x)_CHECKS))
+LIBC_SOCK_OBJS = $(foreach x,$(LIBC_SOCK_ARTIFACTS),$($(x)_OBJS))
+$(LIBC_SOCK_OBJS): $(BUILD_FILES) libc/sock/sock.mk
+
+.PHONY: o/$(MODE)/libc/sock
+o/$(MODE)/libc/sock: $(LIBC_SOCK_CHECKS)

libc/sock/socket-nt.c

@@ -0,0 +1,50 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/internal.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sysv/consts/fio.h"
+#include "libc/sysv/consts/sock.h"
+
+STATIC_YOINK("closesocket$nt");
+STATIC_YOINK("kNtWsaData");
+STATIC_YOINK("recvfrom$nt");
+STATIC_YOINK("sendto$nt");
+
+textwindows int socket$nt(int family, int type, int protocol) {
+  int fd;
+  if ((fd = createfd()) == -1) return -1;
+  if ((g_fds.p[fd].handle =
+           WSASocket(family, type & ~(SOCK_CLOEXEC | SOCK_NONBLOCK), protocol,
+                     NULL, 0, (type & SOCK_CLOEXEC))) != -1) {
+    if (type & SOCK_NONBLOCK) {
+      uint32_t yes = 1;
+      if (__ioctlsocket$nt(g_fds.p[fd].handle, FIONBIO, &yes) == -1) {
+        __closesocket$nt(g_fds.p[fd].handle);
+        return winsockerr();
+      }
+    }
+    g_fds.p[fd].kind = kFdSocket;
+    g_fds.p[fd].flags = type;
+    return fd;
+  } else {
+    return winsockerr();
+  }
+}

libc/sock/socket-sysv.c

@@ -0,0 +1,37 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dce.h"
+#include "libc/errno.h"
+#include "libc/sock/internal.h"
+#include "libc/sysv/consts/sock.h"
+
+int socket$sysv(int family, int type, int protocol) {
+  int rc, olderr, modernflags;
+  olderr = errno;
+  rc = __socket$sysv(family, type, protocol);
+  if ((SupportsLinux() || SupportsXnu()) &&
+      (rc == -1 && errno == EINVAL /* rhel5 behavior */) &&
+      (modernflags = (type & (SOCK_CLOEXEC | SOCK_NONBLOCK)))) {
+    errno = olderr;
+    rc = fixupnewsockfd$sysv(
+        __socket$sysv(family, type & ~modernflags, protocol), modernflags);
+  }
+  return rc;
+}

libc/sock/socket.c

@@ -0,0 +1,53 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dce.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/sysv/consts/af.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Creates new system resource for network communication.
+ *
+ * @param family can be AF_UNIX, AF_INET, etc.
+ * @param type can be SOCK_STREAM (for TCP), SOCK_DGRAM (e.g. UDP), or
+ *     SOCK_RAW (IP) so long as IP_HDRINCL was passed to setsockopt();
+ *     and additionally, may be or'd with SOCK_NONBLOCK, SOCK_CLOEXEC
+ * @param protocol can be IPPROTO_TCP, IPPROTO_UDP, or IPPROTO_ICMP
+ * @return socket file descriptor or -1 w/ errno
+ * @error ENETDOWN, EPFNOSUPPORT, etc.
+ * @see libc/sysv/consts.sh
+ * @asyncsignalsafe
+ */
+int socket(int family, int type, int protocol) {
+  if (family == AF_UNSPEC) {
+    family = AF_INET;
+  } else if (family == AF_INET6) {
+    /* Recommend IPv6 on frontend serving infrastructure only. That's
+       what Google Cloud does. It's more secure. It also means poll()
+       will work on Windows, which doesn't allow mixing third layers. */
+    return epfnosupport();
+  }
+  if (!IsWindows()) {
+    return socket$sysv(family, type, protocol);
+  } else {
+    return socket$nt(family, type, protocol);
+  }
+}

libc/sock/socketconnect.c

@@ -0,0 +1,42 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/dns/dns.h"
+#include "libc/errno.h"
+#include "libc/sock/sock.h"
+
+/**
+ * Opens socket client connection.
+ *
+ * @param ai can be obtained via getaddrinfo()
+ * @return socket file descriptor, or -1 w/ errno
+ */
+int socketconnect(const struct addrinfo *ai, int flags) {
+  int fd;
+  fd = socket(ai->ai_family, ai->ai_socktype | flags, ai->ai_protocol);
+  if (fd != -1) {
+    if (connect(fd, ai->ai_addr, ai->ai_addrlen) != -1 ||
+        errno == EINPROGRESS) {
+      return fd;
+    }
+    close(fd);
+  }
+  return -1;
+}

libc/sock/winsockblock.c

@@ -0,0 +1,46 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/assert.h"
+#include "libc/errno.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+#include "libc/sock/sock.h"
+#include "libc/str/str.h"
+
+textwindows int64_t winsockblock(int64_t fh, unsigned eventbit, int64_t rc) {
+  int64_t eh;
+  struct NtWsaNetworkEvents ev;
+  if (rc != -1) return rc;
+  if (WSAGetLastError() != EWOULDBLOCK) return winsockerr();
+  eh = WSACreateEvent();
+  memset(&ev, 0, sizeof(ev));
+  if (WSAEventSelect(fh, eh, 1u << eventbit) != -1 &&
+      WSAEnumNetworkEvents(fh, eh, &ev) != -1) {
+    if (!ev.iErrorCode[eventbit]) {
+      rc = 0;
+    } else {
+      errno = ev.iErrorCode[eventbit];
+    }
+  } else {
+    winsockerr();
+  }
+  WSACloseEvent(eh);
+  return rc;
+}

libc/sock/winsockerr.c

@@ -0,0 +1,30 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/errno.h"
+#include "libc/nt/winsock.h"
+#include "libc/sock/internal.h"
+
+/**
+ * Error return path for winsock wrappers.
+ */
+textwindows int64_t winsockerr(void) {
+  errno = WSAGetLastError();
+  return -1;
+}

libc/sock/xinet_ntop.c

@@ -0,0 +1,41 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/log/log.h"
+#include "libc/mem/mem.h"
+#include "libc/runtime/runtime.h"
+#include "libc/sock/sock.h"
+
+/**
+ * Formats internet address to string, or dies.
+ *
+ * @param af can be AF_INET, e.g. addr->sin_family
+ * @param src is the binary-encoded address, e.g. &addr->sin_addr
+ * @return allocated IP address string, which must be free()'d
+ */
+char *xinet_ntop(int af, const void *src) {
+  char *res, ip[16];
+  if (inet_ntop(af, src, ip, sizeof(ip)) && (res = strdup(ip))) {
+    return res;
+  } else {
+    if (weaken(die)) weaken(die)();
+    abort();
+    unreachable;
+  }
+}