cosmopolitan/libc/sock/gethostips.c
Justine Tunney 5144c22189 Add test for ioctl(SIOCGIFCONF) and polyfill on BSDs
- Use nullness checks when calling weakly linked functions.

- Avoid typedef for reasons described in Linux Kernel style guide.

- Avoid enum in in Windows headers. Earlier in Cosmo's history all one
  hundred files in libc/nt/enum/ used to be enums and it resulted in
  gigabytes of DWARF data almost as large as everything else in the
  codebase combined.

- Bitfields aren't our friends. They have frequent ABI breakages,
  inconsistent arithmetic across compilers, and different endianness
  between cpus. Compiler authors also haven't invested much roi into
  making bit fields go fast so they produce poor assembly.

- Use memccpy() instead of strncpy() or snprintf() for length-bounded
  copying of C strings. strncpy() is a misunderstood function and
  snprintf() is awesome but memccpy() deserves more love.
2021-06-25 18:44:04 -07:00

122 lines
4.8 KiB
C

/*-*- 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 2021 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/bits.h"
#include "libc/calls/internal.h"
#include "libc/mem/mem.h"
#include "libc/nt/errors.h"
#include "libc/nt/iphlpapi.h"
#include "libc/sock/sock.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/af.h"
#include "libc/sysv/consts/ipproto.h"
#include "libc/sysv/consts/sio.h"
#include "libc/sysv/consts/sock.h"
/* TODO(jart): DELETE */
static uint32_t *GetUnixIps(void) {
int fd, n;
uint64_t z;
uint32_t *a;
char *b, *p, *e, c[16];
if ((fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP)) == -1) return 0;
a = 0;
n = 0;
z = 15000;
b = malloc(z);
memcpy(c, &z, 8);
memcpy(c + (IsXnu() ? 4 : 8), &b, 8);
if (sys_ioctl(fd, SIOCGIFCONF, &c) != -1) {
for (p = b, e = p + MIN(z, READ32LE(c)); p + 16 + 16 <= e;
p += IsBsd() ? 16 + MAX(16, p[16] & 255) : 40) {
if ((p[IsBsd() ? 17 : 16] & 255) != AF_INET) continue;
a = realloc(a, ++n * sizeof(*a));
a[n - 1] = READ32BE(p + 20);
}
a = realloc(a, ++n * sizeof(*a));
a[n - 1] = 0;
}
close(fd);
free(b);
return a;
}
static textwindows uint32_t *GetWindowsIps(void) {
uint32_t i, z, n, rc, *a;
struct NtIpAdapterUnicastAddress *u;
struct NtIpAdapterAddresses *p, *ifaces;
i = 0;
z = 15000;
do {
if (!(ifaces = malloc(z))) return 0;
rc = GetAdaptersAddresses(AF_INET,
kNtGaaFlagSkipAnycast | kNtGaaFlagSkipMulticast |
kNtGaaFlagSkipDnsServer |
kNtGaaFlagSkipFriendlyName,
0, ifaces, &z);
if (rc != kNtErrorBufferOverflow) break;
free(ifaces);
ifaces = 0;
} while (++i < 3);
if (rc == kNtErrorNoData) {
a = calloc(1, sizeof(*a));
} else if (rc == kNtNoError) {
for (a = 0, n = 0, p = ifaces; p; p = p->Next) {
if (p->OperStatus != kNtIfOperStatusUp) continue;
for (u = p->FirstUnicastAddress; u; u = u->Next) {
if (u->Address.lpSockaddr->sa_family != AF_INET) continue;
a = realloc(a, ++n * sizeof(*a));
a[n - 1] = ntohl(
((struct sockaddr_in *)u->Address.lpSockaddr)->sin_addr.s_addr);
}
}
a = realloc(a, ++n * sizeof(*a));
a[n - 1] = 0;
} else {
__winerr();
a = 0;
}
free(ifaces);
return a;
}
/**
* Returns IP addresses of system.
*
* Normally return values will look like `{0x7f000001, 0x0a0a0a7c, 0}`
* which means the same thing as `{"127.0.0.1", "10.10.10.124", 0}`.
* Returned IPs will IPv4 anycast addresses bound to network interfaces
* which come in a NULL-terminated array with no particular ordering.
*
* uint32_t *ip, *ips = GetIps();
* for (ip = ips; *ip; ++ip) {
* printf("%hhu.%hhu.%hhu.%hhu\n", *ip >> 24, *ip >> 16, *ip >> 8, *ip);
* }
*
* This function supports Windows, Linux, XNU, FreeBSD, NetBSD, OpenBSD.
*
* @return null-terminated ip array on success, or null w/ errno
*/
uint32_t *GetHostIps(void) {
if (!IsWindows()) {
return GetUnixIps();
} else {
return GetWindowsIps();
}
}