Get rid of getifaddrs for interface ID detection

Signed-off-by: Steven Barth <steven@midlink.org>

diff --git a/src/ra.c b/src/ra.c
index b21bc5615e5acb65ea1938e742437a80bac22f98..54cf086d11356501bcba02c5cd0cc1bd4aa52f95 100644 (file)
--- a/src/ra.c
+++ b/src/ra.c
@@ -13,7 +13,6 @@
  */
 
 #include <fcntl.h>
-#include <ifaddrs.h>
 #include <stdio.h>
 #include <signal.h>
 #include <string.h>
@@ -252,37 +251,21 @@ bool ra_process(void)
 {
        bool found = false;
        bool changed = false;
-       bool has_lladdr = !IN6_IS_ADDR_UNSPECIFIED(&lladdr);
        uint8_t buf[1500], cmsg_buf[128];
        struct nd_router_advert *adv = (struct nd_router_advert*)buf;
        struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
        const struct in6_addr any = IN6ADDR_ANY_INIT;
 
-       if (!has_lladdr) {
-               // Autodetect interface-id if not specified
-               struct ifaddrs *ifaddr, *ifa;
+       if (IN6_IS_ADDR_UNSPECIFIED(&lladdr)) {
+               struct sockaddr_in6 addr = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, if_index};
+               socklen_t alen = sizeof(addr);
+               int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
 
-               if (getifaddrs(&ifaddr) == 0) {
-                       for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
-                               struct sockaddr_in6 *addr;
+               if (!connect(sock, (struct sockaddr*)&addr, sizeof(addr)) &&
+                               !getsockname(sock, (struct sockaddr*)&addr, &alen))
+                       lladdr = addr.sin6_addr;
 
-                               if (ifa->ifa_addr == NULL || ifa->ifa_addr->sa_family != AF_INET6)
-                                       continue;
-
-                               addr = (struct sockaddr_in6*)ifa->ifa_addr;
-
-                               if (!IN6_IS_ADDR_LINKLOCAL(&addr->sin6_addr))
-                                       continue;
-
-                               if (!strcmp(ifa->ifa_name, if_name)) {
-                                       lladdr = addr->sin6_addr;
-                                       has_lladdr = true;
-                                       break;
-                               }
-                       }
-
-                       freeifaddrs(ifaddr);
-               }
+               close(sock);
        }
 
        while (true) {
@@ -295,7 +278,7 @@ bool ra_process(void)
                if (len <= 0)
                        break;
 
-               if (!has_lladdr)
+               if (IN6_IS_ADDR_UNSPECIFIED(&lladdr))
                        continue;
 
                int hlim = 0;