Send broadcast packets using a random socket, and properly support IPv6.

Before it would always use the first socket, and always send an IPv4 broadcast packet. That
works fine in a lot of situations, but it is better to try all sockets, and to send IPv6 packets
on IPv6 sockets. This is especially important for users that are on IPv6-only networks or that
have multiple physical network interfaces, although in the latter case it probably requires
them to use the ListenAddress variable to create a separate socket for each interface.

diff --git a/src/net_packet.c b/src/net_packet.c
index 5290fd6..2abe16e 100644 (file)
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -541,11 +541,21 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
        /* Overloaded use of priority field: -1 means local broadcast */
 
        if(origpriority == -1 && n->prevedge) {
-               broadcast.in.sin_family = AF_INET;
-               broadcast.in.sin_addr.s_addr = -1;
-               broadcast.in.sin_port = n->prevedge->address.in.sin_port;
+               sock = rand() % listen_sockets;
+               memset(&broadcast, 0, sizeof broadcast);
+               if(listen_socket[sock].sa.sa.sa_family == AF_INET6) {
+                       broadcast.in6.sin6_family = AF_INET6;
+                       broadcast.in6.sin6_addr.s6_addr[0x0] = 0xff;
+                       broadcast.in6.sin6_addr.s6_addr[0x1] = 0x02;
+                       broadcast.in6.sin6_addr.s6_addr[0xf] = 0x01;
+                       broadcast.in6.sin6_port = n->prevedge->address.in.sin_port;
+                       broadcast.in6.sin6_scope_id = listen_socket[sock].sa.in6.sin6_scope_id;
+               } else {
+                       broadcast.in.sin_family = AF_INET;
+                       broadcast.in.sin_addr.s_addr = -1;
+                       broadcast.in.sin_port = n->prevedge->address.in.sin_port;
+               }
                sa = &broadcast;
-               sock = 0;
        } else {
                if(origpriority == -1)
                        origpriority = 0;