Allow overriding the interface-identifier for public addresses

diff --git a/src/odhcp6c.c b/src/odhcp6c.c
index 4fefcd70b2c6521005e29316b3c1048bc2e0996a..df89eb9baeb68c050b620e3541cfd27eccb6d719 100644 (file)
--- a/src/odhcp6c.c
+++ b/src/odhcp6c.c
@@ -27,6 +27,7 @@
 #include <net/if.h>
 #include <sys/wait.h>
 #include <sys/syscall.h>
+#include <arpa/inet.h>
 
 #include "odhcp6c.h"
 #include "ra.h"
@@ -55,11 +56,12 @@ int main(_unused int argc, char* const argv[])
        char *optpos;
        uint16_t opttype;
        enum odhcp6c_ia_mode ia_na_mode = IA_MODE_TRY;
+       static struct in6_addr ifid = IN6ADDR_ANY_INIT;
 
        bool help = false, daemonize = false;
        int logopt = LOG_PID;
        int c, request_pd = 0;
-       while ((c = getopt(argc, argv, "S::N:P:c:r:s:khedp:")) != -1) {
+       while ((c = getopt(argc, argv, "S::N:P:c:i:r:s:khedp:")) != -1) {
                switch (c) {
                case 'S':
                        allow_slaac_only = (optarg) ? atoi(optarg) : -1;
@@ -98,6 +100,11 @@ int main(_unused int argc, char* const argv[])
                        }
                        break;
 
+               case 'i':
+                       if (inet_pton(AF_INET6, optarg, &ifid) != 1)
+                               help = true;
+                       break;
+
                case 'r':
                        optpos = optarg;
                        while (optpos[0]) {
@@ -151,7 +158,7 @@ int main(_unused int argc, char* const argv[])
        signal(SIGUSR2, sighandler);
 
        if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
-                       init_dhcpv6(ifname, request_pd) || ra_init(ifname) ||
+                       init_dhcpv6(ifname, request_pd) || ra_init(ifname, &ifid) ||
                        script_init(script, ifname)) {
                syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
                return 3;
@@ -314,6 +321,7 @@ static int usage(void)
        "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
        "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
        "       -c <clientid>   Override client-ID (base-16 encoded)\n"
+       "       -i <iface-id>   Use a custom interface identifier for RA handling\n"
        "       -r <options>    Options to be requested (comma-separated)\n"
        "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
        "       -k              Don't send a RELEASE when stopping\n"

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

diff --git a/src/ra.h b/src/ra.h
index f87c4f73590961157413f4086d473b05a113ae8b..f66ff2672cd0353a6bea90e4313d0973ddcedaa6 100644 (file)
--- a/src/ra.h
+++ b/src/ra.h
@@ -34,6 +34,6 @@ struct icmpv6_opt {
        (void*)(opt + opt->len) <= (void*)(end); opt += opt->len)
 
 
-int ra_init(const char *ifname);
+int ra_init(const char *ifname, const struct in6_addr *ifid);
 bool ra_process(void);
 bool ra_rtnl_process(void);