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Ensure MTU probe replies are sent back the same way they came in.

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Also sprinkle some comments over mtu_probe_h().
This commit is contained in:
Guus Sliepen 2012-11-19 14:20:50 +01:00
parent 3c1b704733
commit d30b9e1272
1 changed files with 19 additions and 2 deletions
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21
src/net_packet.c
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@ -164,10 +164,25 @@ static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
logger(DEBUG_TRAFFIC, LOG_INFO, "Got MTU probe length %d from %s (%s)", packet->len, n->name, n->hostname);
if(!packet->data[0]) {
/* It's a probe request, send back a reply */
packet->data[0] = 1;
send_udppacket(n, packet);
} else {
/* Temporarily set udp_confirmed, so that the reply is sent
back exactly the way it came in. */
bool udp_confirmed = n->status.udp_confirmed;
n->status.udp_confirmed = true;
send_udppacket(n, packet);
n->status.udp_confirmed = udp_confirmed;
} else {
/* It's a valid reply: now we know bidirectional communication
is possible using the address and socket that the reply
packet used. */
n->status.udp_confirmed = true;
/* If we haven't established the PMTU yet, restart the discovery process. */
if(n->mtuprobes > 30) {
if(n->minmtu)
@ -176,6 +191,8 @@ static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
n->mtuprobes = 1;
}
/* If applicable, raise the minimum supported MTU */
if(len > n->maxmtu)
len = n->maxmtu;
if(n->minmtu < len)