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cosmopolitan/libc/sock/ifaddrs.c
Hugues Morisset f1e83d5240
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Add IPv6 support to getifaddrs() on Linux (#1415)
2025-05-21 01:20:22 -07:00

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9.1 KiB
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 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/sock/ifaddrs.h"
#include "libc/calls/calls.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/dce.h"
#include "libc/limits.h"
#include "libc/mem/mem.h"
#include "libc/sock/sock.h"
#include "libc/sock/struct/ifconf.h"
#include "libc/sock/struct/ifreq.h"
#include "libc/sock/struct/sockaddr6.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/af.h"
#include "libc/sysv/consts/iff.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/sio.h"
#include "libc/sysv/consts/sock.h"
struct IfAddr {
struct ifaddrs ifaddrs;
char name[IFNAMSIZ];
struct sockaddr_in addr;
struct sockaddr_in netmask;
struct sockaddr_in bstaddr;
};
struct IfAddr6Info {
int addr_scope;
int addr_flags;
};
struct IfAddr6 {
struct ifaddrs ifaddrs;
char name[IFNAMSIZ];
struct sockaddr_in6 addr;
struct sockaddr_in6 netmask;
struct sockaddr_in6 bstaddr; // unused
struct IfAddr6Info info;
};
/**
* Frees network interface address list.
*/
void freeifaddrs(struct ifaddrs *ifp) {
struct ifaddrs *next;
while (ifp) {
next = ifp->ifa_next;
free(ifp);
ifp = next;
}
}
// hex repr to network order int
static uint128_t hex2no(const char *str) {
uint128_t res = 0;
const int max_quads = sizeof(uint128_t) * 2;
int i = 0;
while ((i < max_quads) && str[i]) {
uint8_t acc = (((str[i] & 0xF) + (str[i] >> 6)) | ((str[i] >> 3) & 0x8));
acc = acc << 4;
i += 1;
if (str[i]) {
acc = acc | (((str[i] & 0xF) + (str[i] >> 6)) | ((str[i] >> 3) & 0x8));
i += 1;
}
res = (res >> 8) | (((uint128_t)acc) << ((sizeof(uint128_t) - 1) * 8));
}
res = res >> ((max_quads - i) * 4);
return res;
}
/**
* Gets network interface IPv6 address list on linux.
*
* @return 0 on success, or -1 w/ errno
*/
static int getifaddrs_linux_ip6(struct ifconf *conf) {
int fd;
int n = 0;
struct ifreq *ifreq = conf->ifc_req;
const int bufsz = 44 + IFNAMSIZ + 1;
char buf[bufsz + 1]; // one line max size
if ((fd = sys_openat(0, "/proc/net/if_inet6", O_RDONLY, 0)) == -1) {
return -1;
}
while ((n = sys_read(fd, &buf[n], bufsz - n)) &&
((char *)ifreq < (conf->ifc_buf + conf->ifc_len))) {
// flags linux include/uapi/linux/if_addr.h:44
// scope linux include/net/ipv6.h:L99
// *addr, *index, *plen, *scope, *flags, *ifname
char *s[] = {&buf[0], &buf[33], &buf[36], &buf[39], &buf[42], &buf[45]};
int ifnamelen = 0;
while (*s[5] == ' ') {
++s[5];
}
while (s[5][ifnamelen] > '\n') {
++ifnamelen;
}
buf[32] = buf[35] = buf[38] = buf[41] = buf[44] = s[5][ifnamelen] = '\0';
bzero(ifreq, sizeof(*ifreq));
ifreq->ifr_addr.sa_family = AF_INET6;
memcpy(&ifreq->ifr_name, s[5], ifnamelen);
*((uint128_t *)&ifreq->ifr6_addr) = hex2no(s[0]);
ifreq->ifr6_ifindex = hex2no(s[1]);
ifreq->ifr6_prefixlen = hex2no(s[2]);
ifreq->ifr6_scope = hex2no(s[3]);
ifreq->ifr6_flags = hex2no(s[4]);
++ifreq;
int tlen = &s[5][ifnamelen] - &buf[0] + 1;
n = bufsz - tlen;
memcpy(&buf, &buf[tlen], n);
}
conf->ifc_len = (char *)ifreq - conf->ifc_buf;
return sys_close(fd);
}
/**
* Gets network interface address list.
*
* @return 0 on success, or -1 w/ errno
* @see tool/viz/getifaddrs.c for example code
*/
int getifaddrs(struct ifaddrs **out_ifpp) {
// printf("%d\n", sizeof(struct ifreq));
int rc = -1;
int fd;
if ((fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0)) != -1) {
char *data;
size_t size;
if ((data = malloc((size = 16384)))) {
struct ifconf conf;
conf.ifc_buf = data;
conf.ifc_len = size;
if (!ioctl(fd, SIOCGIFCONF, &conf)) {
if (IsLinux()) {
struct ifconf confl6;
confl6.ifc_buf = data + conf.ifc_len;
confl6.ifc_len = size - conf.ifc_len;
if ((rc = getifaddrs_linux_ip6(&confl6)))
return rc;
conf.ifc_len += confl6.ifc_len;
}
struct ifaddrs *res = 0;
for (struct ifreq *ifr = (struct ifreq *)data;
(char *)ifr < data + conf.ifc_len; ++ifr) {
uint16_t family = ifr->ifr_addr.sa_family;
if (family == AF_INET) {
struct IfAddr *addr;
if ((addr = calloc(1, sizeof(struct IfAddr)))) {
memcpy(addr->name, ifr->ifr_name, IFNAMSIZ);
addr->ifaddrs.ifa_name = addr->name;
memcpy(&addr->addr, &ifr->ifr_addr, sizeof(struct sockaddr_in));
addr->ifaddrs.ifa_addr = (struct sockaddr *)&addr->addr;
addr->ifaddrs.ifa_netmask = (struct sockaddr *)&addr->netmask;
if (!ioctl(fd, SIOCGIFFLAGS, ifr)) {
addr->ifaddrs.ifa_flags = ifr->ifr_flags;
}
if (!ioctl(fd, SIOCGIFNETMASK, ifr)) {
memcpy(&addr->netmask, &ifr->ifr_addr,
sizeof(struct sockaddr_in));
}
unsigned long op;
if (addr->ifaddrs.ifa_flags & IFF_BROADCAST) {
op = SIOCGIFBRDADDR;
} else if (addr->ifaddrs.ifa_flags & IFF_POINTOPOINT) {
op = SIOCGIFDSTADDR;
} else {
op = 0;
}
if (op && !ioctl(fd, op, ifr)) {
memcpy(&addr->bstaddr, &ifr->ifr_addr,
sizeof(struct sockaddr_in));
addr->ifaddrs.ifa_broadaddr = // is union'd w/ ifu_dstaddr
(struct sockaddr *)&addr->bstaddr;
}
addr->ifaddrs.ifa_next = res;
res = (struct ifaddrs *)addr;
}
} else if (family == AF_INET6) {
struct IfAddr6 *addr6;
if ((addr6 = calloc(1, sizeof(struct IfAddr6)))) {
addr6->ifaddrs.ifa_name = addr6->name;
addr6->ifaddrs.ifa_addr = (struct sockaddr *)&addr6->addr;
addr6->ifaddrs.ifa_netmask = (struct sockaddr *)&addr6->netmask;
addr6->ifaddrs.ifa_broadaddr = (struct sockaddr *)&addr6->bstaddr;
addr6->ifaddrs.ifa_data = (void *)&addr6->info;
memcpy(&addr6->name, &ifr->ifr_name, IFNAMSIZ);
addr6->info.addr_flags = ifr->ifr6_flags;
addr6->info.addr_scope = ifr->ifr6_scope;
addr6->addr.sin6_family = AF_INET6;
addr6->addr.sin6_port = 0;
addr6->addr.sin6_flowinfo = 0;
addr6->addr.sin6_scope_id = ifr->ifr6_ifindex;
memcpy(&addr6->addr.sin6_addr, &ifr->ifr6_addr,
sizeof(struct in6_addr));
addr6->netmask.sin6_family = AF_INET6;
addr6->netmask.sin6_port = 0;
addr6->netmask.sin6_flowinfo = 0;
addr6->addr.sin6_scope_id = ifr->ifr6_ifindex;
memcpy(&addr6->netmask.sin6_addr, &ifr->ifr6_addr,
sizeof(struct in6_addr));
*((uint128_t *)&(addr6->netmask.sin6_addr)) &=
(UINT128_MAX >> ifr->ifr6_prefixlen);
if (!ioctl(fd, SIOCGIFFLAGS, ifr)) {
addr6->ifaddrs.ifa_flags = ifr->ifr_flags;
}
bzero(&addr6->bstaddr, sizeof(struct sockaddr_in6));
addr6->ifaddrs.ifa_next = res;
res = (struct ifaddrs *)addr6;
}
}
}
*out_ifpp = res;
rc = 0;
}
free(data);
}
close(fd);
}
return rc;
}
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