Allow overriding the interface-identifier for public addresses

[odhcp6c.git] / src / ra.c

diff --git a/src/ra.c b/src/ra.c
index b1526aed6ccacaba046b10072fd8e8887628fb29..4690d419466975357a5a9bce667f469c633f87b2 100644 (file)
--- a/src/ra.c
+++ b/src/ra.c
@@ -42,11 +42,12 @@ static struct in6_addr lladdr = IN6ADDR_ANY_INIT;
 
 static void ra_send_rs(int signal __attribute__((unused)));
 
-int ra_init(const char *ifname)
+int ra_init(const char *ifname, const struct in6_addr *ifid)
 {
        sock = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC, IPPROTO_ICMPV6);
        if_index = if_nametoindex(ifname);
        strncpy(if_name, ifname, sizeof(if_name) - 1);
+       lladdr = *ifid;
 
        // Filter ICMPv6 package types
        struct icmp6_filter filt;
@@ -74,17 +75,19 @@ int ra_init(const char *ifname)
        fcntl(sock, F_SETOWN, ourpid);
        fcntl(sock, F_SETFL, fcntl(sock, F_GETFL) | O_ASYNC);
 
-       // Get LL-addr
-       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);
-                               break;
+       if (IN6_IS_ADDR_UNSPECIFIED(&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);
+                                       break;
+                               }
                        }
+                       fclose(fp);
                }
-               fclose(fp);
        }
 
        // Open rtnetlink socket