Fast handoff of roaming MAC addresses.

In switch mode, if a known MAC address is claimed by a second node before it
expired at the first node, it is likely that this is because a computer has
roamed from the LAN of the first node to that of the second node. To ensure
packets for that computer are routed to the second node, the first node should
delete its corresponding Subnet as soon as possible, without waiting for the
normal expiry timeout.

diff --git a/src/protocol_subnet.c b/src/protocol_subnet.c
index f7ce53b961de88a0edd4ad1205c181a7c8417e0e..ba75c89988493db3ae835c397f79f970bb25f676 100644 (file)
--- a/src/protocol_subnet.c
+++ b/src/protocol_subnet.c
@@ -45,7 +45,7 @@ bool add_subnet_h(connection_t *c) {
        char subnetstr[MAX_STRING_SIZE];
        char name[MAX_STRING_SIZE];
        node_t *owner;
-       subnet_t s = {0}, *new;
+       subnet_t s = {0}, *new, *old;
 
        if(sscanf(c->buffer, "%*d %*x " MAX_STRING " " MAX_STRING, name, subnetstr) != 2) {
                logger(LOG_ERR, "Got bad %s from %s (%s)", "ADD_SUBNET", c->name,
@@ -142,6 +142,11 @@ bool add_subnet_h(connection_t *c) {
        if(!tunnelserver)
                forward_request(c);
 
+       /* Fast handoff of roaming MAC addresses */
+
+       if(s.type == SUBNET_MAC && owner != myself && (old = lookup_subnet(myself, &s)) && old->expires)
+               old->expires = now;
+
        return true;
 }