void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
ifdebug(TRAFFIC) logger(LOG_INFO, "Got MTU probe length %d from %s (%s)", packet->len, n->name, n->hostname);
if(!packet->data[0]) {
packet->data[0] = 1;
send_udppacket(n, packet);
} else {
if(n->mtuprobes > 30) {
if (len == n->maxmtu + 8) {
ifdebug(TRAFFIC) logger(LOG_INFO, "Increase in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname);
n->maxmtu = MTU;
n->mtuprobes = 10;
return;
}
if(n->minmtu)
n->mtuprobes = 30;
else
n->mtuprobes = 1;
}
if(len > n->maxmtu)
len = n->maxmtu;
if(n->minmtu < len)
n->minmtu = len;
}
}
void send_mtu_probe(node_t *n) {
vpn_packet_t packet;
int len, i;
int timeout = 1;
n->mtuprobes++;
n->mtuevent = NULL;
if(!n->status.reachable || !n->status.validkey) {
ifdebug(TRAFFIC) logger(LOG_INFO, "Trying to send MTU probe to unreachable or rekeying node %s (%s)", n->name, n->hostname);
n->mtuprobes = 0;
return;
}
if(n->mtuprobes > 32) {
if(!n->minmtu) {
n->mtuprobes = 31;
timeout = pinginterval;
goto end;
}
ifdebug(TRAFFIC) logger(LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
n->mtuprobes = 1;
n->minmtu = 0;
n->maxmtu = MTU;
}
if(n->mtuprobes >= 10 && n->mtuprobes < 32 && !n->minmtu) {
ifdebug(TRAFFIC) logger(LOG_INFO, "No response to MTU probes from %s (%s)", n->name, n->hostname);
n->mtuprobes = 31;
}
if(n->mtuprobes == 30 || (n->mtuprobes < 30 && n->minmtu >= n->maxmtu)) {
if(n->minmtu > n->maxmtu)
n->minmtu = n->maxmtu;
else
n->maxmtu = n->minmtu;
n->mtu = n->minmtu;
ifdebug(TRAFFIC) logger(LOG_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes);
n->mtuprobes = 31;
}
if(n->mtuprobes == 31) {
timeout = pinginterval;
goto end;
} else if(n->mtuprobes == 32) {
timeout = pingtimeout;
}
for(i = 0; i < 4 + localdiscovery; i++) {
if(i == 0) {
if(n->mtuprobes < 30 || n->maxmtu + 8 >= MTU)
continue;
len = n->maxmtu + 8;
} else if(n->maxmtu <= n->minmtu) {
len = n->maxmtu;
} else {
len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
}
if(len < 64)
len = 64;
memset(packet.data, 0, 14);
RAND_pseudo_bytes(packet.data + 14, len - 14);
packet.len = len;
if(i >= 4 && n->mtuprobes <= 10)
packet.priority = -1;
else
packet.priority = 0;
ifdebug(TRAFFIC) logger(LOG_INFO, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname);
send_udppacket(n, &packet);
}
end:
n->mtuevent = new_event();
n->mtuevent->handler = (event_handler_t)send_mtu_probe;
n->mtuevent->data = n;
n->mtuevent->time = now.tv_sec + timeout;
event_add(n->mtuevent);
}
static void send_mtu_probe_handler(event_loop_t *loop, void *data) {
meshlink_handle_t *mesh = loop->data;
node_t *n = data;
int timeout = 1;
n->mtuprobes++;
if(!n->status.reachable || !n->status.validkey) {
logger(mesh, MESHLINK_INFO, "Trying to send MTU probe to unreachable or rekeying node %s (%s)", n->name, n->hostname);
n->mtuprobes = 0;
return;
}
if(n->mtuprobes > 32) {
if(!n->minmtu) {
n->mtuprobes = 31;
timeout = mesh->pinginterval;
goto end;
}
logger(mesh, MESHLINK_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
n->status.udp_confirmed = false;
n->mtuprobes = 1;
n->minmtu = 0;
n->maxmtu = MTU;
}
if(n->mtuprobes >= 10 && n->mtuprobes < 32 && !n->minmtu) {
logger(mesh, MESHLINK_INFO, "No response to MTU probes from %s (%s)", n->name, n->hostname);
n->mtuprobes = 31;
}
if(n->mtuprobes == 30 || (n->mtuprobes < 30 && n->minmtu >= n->maxmtu)) {
if(n->minmtu > n->maxmtu)
n->minmtu = n->maxmtu;
else
n->maxmtu = n->minmtu;
n->mtu = n->minmtu;
logger(mesh, MESHLINK_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes);
n->mtuprobes = 31;
}
if(n->mtuprobes == 31) {
timeout = mesh->pinginterval;
goto end;
} else if(n->mtuprobes == 32) {
timeout = mesh->pingtimeout;
}
for(int i = 0; i < 4 + mesh->localdiscovery; i++) {
int len;
if(i == 0) {
if(n->mtuprobes < 30 || n->maxmtu + 8 >= MTU)
continue;
len = n->maxmtu + 8;
} else if(n->maxmtu <= n->minmtu) {
len = n->maxmtu;
} else {
len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
}
if(len < 64)
len = 64;
vpn_packet_t packet;
packet.probe = true;
memset(packet.data, 0, 14);
randomize(packet.data + 14, len - 14);
packet.len = len;
n->status.broadcast = i >= 4 && n->mtuprobes <= 10 && n->prevedge;
logger(mesh, MESHLINK_DEBUG, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname);
send_udppacket(mesh, n, &packet);
}
n->status.broadcast = false;
n->probe_counter = 0;
gettimeofday(&n->probe_time, NULL);
/* Calculate the packet loss of incoming traffic by comparing the rate of
packets received to the rate with which the sequence number has increased.
*/
if(n->received > n->prev_received)
n->packetloss = 1.0 - (n->received - n->prev_received) / (float)(n->received_seqno - n->prev_received_seqno);
else
n->packetloss = n->received_seqno <= n->prev_received_seqno;
n->prev_received_seqno = n->received_seqno;
n->prev_received = n->received;
end:
timeout_set(&mesh->loop, &n->mtutimeout, &(struct timeval){timeout, rand() % 100000});
