Send router solicitations with source link-layer address

[odhcp6c.git] / src / ra.c

diff --git a/src/ra.c b/src/ra.c
index ceded54ab9340c90be76b19b3802c0bad576bfa9..b700c9a8270a10aba5a162f10d0c4c061e785e27 100644 (file)
--- a/src/ra.c
+++ b/src/ra.c
@@ -1,5 +1,5 @@
 /**
- * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
+ * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License v2 as published by
@@ -13,6 +13,7 @@
  */
 
 #include <fcntl.h>
+#include <ifaddrs.h>
 #include <stdio.h>
 #include <signal.h>
 #include <string.h>
@@ -24,6 +25,8 @@
 #include <net/if.h>
 #include <arpa/inet.h>
 #include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
 #include <netinet/in.h>
 #include <netinet/icmp6.h>
 
@@ -130,9 +133,26 @@ int ra_init(const char *ifname, const struct in6_addr *ifid)
 
 static void ra_send_rs(int signal __attribute__((unused)))
 {
-       const struct icmp6_hdr rs = {ND_ROUTER_SOLICIT, 0, 0, {{0}}};
+       struct {
+               struct icmp6_hdr hdr;
+               struct icmpv6_opt lladdr;
+       } rs = {
+               .hdr = {ND_ROUTER_SOLICIT, 0, 0, {{0}}},
+               .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
+       };
        const struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, if_index};
-       sendto(sock, &rs, sizeof(rs), MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest));
+       size_t len = sizeof(rs);
+
+       struct ifreq ifr;
+       memset(&ifr, 0, sizeof(ifr));
+       strncpy(ifr.ifr_name, if_name, sizeof(ifr.ifr_name));
+       if (!ioctl(sock, SIOCGIFHWADDR, &ifr)
+                       && memcmp(rs.lladdr.data, ifr.ifr_hwaddr.sa_data, 6))
+               memcpy(rs.lladdr.data, ifr.ifr_hwaddr.sa_data, 6);
+       else
+               len = sizeof(struct icmp6_hdr);
+
+       sendto(sock, &rs, len, MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest));
 
        if (++rs_attempt <= 3)
                alarm(4);
@@ -225,23 +245,36 @@ 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};
+       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 (IN6_IS_ADDR_UNSPECIFIED(&lladdr)) {
+       if (!has_lladdr) {
                // Autodetect interface-id if not specified
-               FILE *fp = fopen("/proc/net/if_inet6", "r");
-               if (fp) {
-                       char addrbuf[33], ifbuf[16];
-                       while (fscanf(fp, "%32s %*x %*x %*x %*x %15s", addrbuf, ifbuf) == 2) {
-                               if (!strcmp(ifbuf, if_name)) {
-                                       script_unhexlify((uint8_t*)&lladdr, sizeof(lladdr), addrbuf);
+               struct ifaddrs *ifaddr, *ifa;
+
+               if (getifaddrs(&ifaddr) == 0) {
+                       for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
+                               struct sockaddr_in6 *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;
                                }
                        }
-                       fclose(fp);
+
+                       freeifaddrs(ifaddr);
                }
        }
 
@@ -255,6 +288,9 @@ bool ra_process(void)
                if (len <= 0)
                        break;
 
+               if (!has_lladdr)
+                       continue;
+
                int hlim = 0;
                for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
                                ch = CMSG_NXTHDR(&msg, ch))
@@ -293,11 +329,13 @@ bool ra_process(void)
                        update_proc("conf", "hop_limit", adv->nd_ra_curhoplimit);
 
                // Parse ND parameters
-               if (ntohl(adv->nd_ra_reachable) <= 3600000)
-                       update_proc("neigh", "base_reachable_time_ms", ntohl(adv->nd_ra_reachable));
+               uint32_t reachable = ntohl(adv->nd_ra_reachable);
+               if (reachable > 0 && reachable <= 3600000)
+                       update_proc("neigh", "base_reachable_time_ms", reachable);
 
-               if (ntohl(adv->nd_ra_retransmit) <= 60000)
-                       update_proc("neigh", "retrans_time_ms", ntohl(adv->nd_ra_retransmit));
+               uint32_t retransmit = ntohl(adv->nd_ra_retransmit);
+               if (retransmit > 0 && retransmit <= 60000)
+                       update_proc("neigh", "retrans_time_ms", retransmit);
 
 
                // Evaluate options