+/* (C) 2013 John Spencer. released under musl's standard MIT license. */
+#undef _GNU_SOURCE
+#define _GNU_SOURCE
+#include <ifaddrs.h>
+#include <stdlib.h>
+#include <net/if.h> /* IFNAMSIZ, ifreq, ifconf */
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include <errno.h>
+#include <arpa/inet.h> /* inet_pton */
+#include <unistd.h>
+#include <sys/ioctl.h>
+
+static struct ifaddrs* list_add(struct ifaddrs** list, struct ifaddrs** head, char* ifname)
+{
+ struct ifaddrs* curr = calloc(1, sizeof(struct ifaddrs));
+ if(curr) {
+ curr->ifa_name = strdup(ifname);
+ if(!curr->ifa_name) {
+ free(curr);
+ curr = 0;
+ goto out;
+ }
+ if(*head) (*head)->ifa_next = curr;
+ *head = curr;
+ if(!*list) *list = curr;
+ }
+ out:
+ return curr;
+}
+
+void freeifaddrs(struct ifaddrs *ifp)
+{
+ struct ifaddrs *head = ifp;
+ while(head) {
+ free(head->ifa_name);
+ free(head->ifa_addr);
+ free(head->ifa_netmask);
+ free(head->ifa_ifu.ifu_dstaddr);
+ free(head->ifa_data);
+ void *p = head;
+ head = head->ifa_next;
+ free(p);
+ }
+}
+
+static struct sockaddr *sockaddr_in_dup(struct sockaddr_in *src)
+{
+ struct sockaddr_in *nu = malloc(sizeof(struct sockaddr_in));
+ if(nu) *nu = *src;
+ return (struct sockaddr*) nu;
+}
+
+static struct sockaddr *sockaddr_in6_dup(struct sockaddr_in6 *src)
+{
+ struct sockaddr_in6 *nu = malloc(sizeof(struct sockaddr_in6));
+ if(nu) *nu = *src;
+ return (struct sockaddr*) nu;
+}
+
+static void ipv6netmask(unsigned prefix_length, struct sockaddr_in6 *sa)
+{
+ // FIXME: left for bit-wizard rich
+ memset(&sa->sin6_addr, -1, sizeof(sa->sin6_addr));
+}
+
+static void dealwithipv6(struct ifaddrs **list, struct ifaddrs** head)
+{
+ FILE* f = fopen("/proc/net/if_inet6", "r");
+ /* 00000000000000000000000000000001 01 80 10 80 lo
+ A B C D E F
+ all numbers in hex
+ A = addr B=netlink device#, C=prefix length,
+ D = scope value (ipv6.h) E = interface flags (rnetlink.h, addrconf.c)
+ F = if name */
+ char v6conv[32 + 7 + 1], *v6;
+ char *line, linebuf[512];
+ if(!f) return;
+ while((line = fgets(linebuf, sizeof linebuf, f))) {
+ v6 = v6conv;
+ size_t i = 0;
+ for(; i < 8; i++) {
+ memcpy(v6, line, 4);
+ v6+=4;
+ *v6++=':';
+ line+=4;
+ }
+ --v6; *v6 = 0;
+ line++;
+ unsigned b, c, d, e;
+ char name[IFNAMSIZ+1];
+ if(5 == sscanf(line, "%x %x %x %x %s", &b, &c, &d, &e, name)) {
+ struct sockaddr_in6 sa = {0};
+ if(1 == inet_pton(AF_INET6, v6conv, &sa.sin6_addr)) {
+ sa.sin6_family = AF_INET6;
+ struct ifaddrs* curr = list_add(list, head, name);
+ if(!curr) goto out;
+ curr->ifa_addr = sockaddr_in6_dup(&sa);
+ ipv6netmask(c, &sa);
+ curr->ifa_netmask = sockaddr_in6_dup(&sa);
+ /* find ipv4 struct with the same interface name to copy flags */
+ struct ifaddrs* scan = *list;
+ for(;scan && strcmp(name, scan->ifa_name);scan=scan->ifa_next);
+ if(scan) curr->ifa_flags=scan->ifa_flags;
+ else curr->ifa_flags = 0;
+ } else errno = 0;
+ }
+ }
+ out:
+ fclose(f);
+}
+
+int getifaddrs(struct ifaddrs **ifap)
+{
+ FILE* f = fopen("/proc/net/dev", "r");
+ /* the alternative to parsing /proc.. seems to be iterating
+ through the interfaces using an index number in ifreq.ifr_ifindex
+ until we get some error code back. the kernel will fill ifr_name field
+ for valid ifindices (SIOCGIFINDEX) */
+ if(!f) return -1;
+ struct ifaddrs *list = 0, *head = 0;
+
+ char* line; char linebuf[512];
+ while((line = fgets(linebuf, sizeof linebuf, f))) {
+ while(isspace(*line) && *line) line++;
+ char* start = line;
+ while(*line && isalnum(*line)) line++;
+ if(line > start && *line == ':') {
+ // found interface
+ *line = 0;
+ struct ifaddrs* curr = list_add(&list, &head, start);
+ if(!curr) {
+ fclose(f);
+ goto err2;
+ }
+ }
+ }
+ fclose(f);
+
+ int sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
+ if(sock == -1) goto err2;
+ struct ifreq reqs[32]; /* arbitrary chosen boundary */
+ struct ifconf conf = {.ifc_len = sizeof reqs, .ifc_req = reqs};
+ if(-1 == ioctl(sock, SIOCGIFCONF, &conf)) goto err;
+ else {
+ size_t reqitems = conf.ifc_len / sizeof(struct ifreq);
+ for(head = list; head; head=head->ifa_next) {
+ size_t i;
+ for(i = 0; i < reqitems; i++) {
+ // get SIOCGIFADDR of active interfaces.
+ if(!strcmp(reqs[i].ifr_name, head->ifa_name)) {
+ head->ifa_addr = sockaddr_in_dup((struct sockaddr_in*) &reqs[i].ifr_addr);
+ break;
+ }
+ }
+ struct ifreq req;
+ snprintf(req.ifr_name, sizeof req.ifr_name, "%s", head->ifa_name);
+ if(-1 == ioctl(sock, SIOCGIFFLAGS, &req)) goto err;
+
+ head->ifa_flags = req.ifr_flags;
+ if(head->ifa_addr) {
+ /* or'ing flags with IFF_LOWER_UP on active interfaces to mimic glibc */
+ head->ifa_flags |= IFF_LOWER_UP;
+ if(-1 == ioctl(sock, SIOCGIFNETMASK, &req)) goto err;
+ head->ifa_netmask = sockaddr_in_dup((struct sockaddr_in*) &req.ifr_netmask);
+
+ if(head->ifa_flags & IFF_POINTOPOINT) {
+ if(-1 == ioctl(sock, SIOCGIFDSTADDR, &req)) goto err;
+ head->ifa_ifu.ifu_dstaddr = sockaddr_in_dup((struct sockaddr_in*) &req.ifr_dstaddr);
+ } else {
+ if(-1 == ioctl(sock, SIOCGIFBRDADDR, &req)) goto err;
+ head->ifa_ifu.ifu_broadaddr = sockaddr_in_dup((struct sockaddr_in*) &req.ifr_broadaddr);
+ }
+ }
+ }
+ }
+ close(sock);
+ void* last = 0;
+ for(head = list; head; head=head->ifa_next) last=head;
+ head = last;
+ dealwithipv6(&list, &head);
+ *ifap = list;
+ return 0;
+ err:
+ close(sock);
+ err2:
+ freeifaddrs(list);
+ return -1;
+}
+
projects / musl / commitdiff