respond to arp requests to the local address

[project/relayd.git] / main.c

diff --git a/main.c b/main.c
index 407c8c2..c30526e 100644 (file)
--- a/main.c
+++ b/main.c
@@ -40,6 +40,9 @@ static int inet_sock;
 static int forward_bcast;
 static int forward_dhcp;
 
+uint8_t local_addr[4];
+int local_route_table;
+
 struct relayd_pending_route {
        struct relayd_route rt;
        struct uloop_timeout timeout;
@@ -342,6 +345,11 @@ static void recv_arp_request(struct relayd_interface *rif, struct arp_packet *pk
        if (!memcmp(pkt->arp.arp_spa, "\x00\x00\x00\x00", 4))
                return;
 
+       if (local_route_table && !memcmp(pkt->arp.arp_tpa, local_addr, sizeof(local_addr))) {
+               send_arp_reply(rif, local_addr, pkt->arp.arp_sha, pkt->arp.arp_spa);
+               return;
+       }
+
        relayd_refresh_host(rif, pkt->eth.ether_shost, pkt->arp.arp_spa);
 
        host = find_host_by_ipaddr(NULL, pkt->arp.arp_tpa);
@@ -641,6 +649,7 @@ static int usage(const char *progname)
                        "       -T <table>      Set routing table number for automatically added routes\n"
                        "       -B              Enable broadcast forwarding\n"
                        "       -D              Enable DHCP forwarding\n"
+                       "       -L <ipaddr>     Enable local access using <ipaddr> as source address\n"
                        "\n",
                progname);
        return -1;
@@ -650,6 +659,7 @@ int main(int argc, char **argv)
 {
        struct relayd_interface *rif = NULL;
        struct in_addr addr, addr2;
+       bool local_addr_valid = false;
        bool managed;
        int ifnum = 0;
        char *s, *s2;
@@ -665,9 +675,10 @@ int main(int argc, char **argv)
 
        host_timeout = 60;
        forward_bcast = 0;
+       local_route_table = 0;
        uloop_init();
 
-       while ((ch = getopt(argc, argv, "I:i:t:BDdT:G:R:")) != -1) {
+       while ((ch = getopt(argc, argv, "I:i:t:BDdT:G:R:L:")) != -1) {
                switch(ch) {
                case 'I':
                        managed = true;
@@ -706,6 +717,14 @@ int main(int argc, char **argv)
                        }
                        relayd_add_pending_route((uint8_t *) &addr.s_addr, (const uint8_t *) "\x00\x00\x00\x00", 0, 0);
                        break;
+               case 'L':
+                       if (!inet_aton(optarg, &addr)) {
+                               fprintf(stderr, "Address '%s' not found\n", optarg);
+                               return 1;
+                       }
+                       memcpy(&local_addr, &addr.s_addr, sizeof(local_addr));
+                       local_addr_valid = true;
+                       break;
                case 'R':
                        s = strchr(optarg, ':');
                        if (!s)
@@ -755,6 +774,9 @@ int main(int argc, char **argv)
        signal(SIGUSR1, die);
        signal(SIGUSR2, die);
 
+       if (local_addr_valid)
+               local_route_table = route_table++;
+
        if (relayd_rtnl_init() < 0)
                return 1;