logger(DEBUG_TRAFFIC, LOG_INFO, "Too much time has elapsed since last UDP ping response from %s (%s), stopping UDP communication", n->name, n->hostname);
n->status.udp_confirmed = false;
+ n->maxrecentlen = 0;
n->mtuprobes = 0;
n->minmtu = 0;
n->maxmtu = MTU;
}
-static void udp_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
- if(!DATA(packet)[0]) {
- /* It's a probe request, send back a reply */
+static void send_udp_probe_reply(node_t *n, vpn_packet_t *packet, length_t len) {
+ if(!n->status.sptps && !n->status.validkey) {
+ // But not if we don't have his key.
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Got UDP probe request from %s (%s) but we don't have his key yet", n->name, n->hostname);
+ return;
+ }
- if(!n->status.sptps && !n->status.validkey) {
- // But not if we don't have his key.
- logger(DEBUG_TRAFFIC, LOG_INFO, "Got UDP probe request from %s (%s) but we don't have his key yet", n->name, n->hostname);
- return;
- }
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Got UDP probe request %d from %s (%s)", packet->len, n->name, n->hostname);
- logger(DEBUG_TRAFFIC, LOG_INFO, "Got UDP probe request %d from %s (%s)", packet->len, n->name, n->hostname);
+ /* Type 2 probe replies were introduced in protocol 17.3 */
+ if ((n->options >> 24) >= 3) {
+ uint8_t *data = DATA(packet);
+ *data++ = 2;
+ uint16_t len16 = htons(len);
+ memcpy(data, &len16, 2);
+ packet->len = MIN_PROBE_SIZE;
+ } else {
+ /* Legacy protocol: n won't understand type 2 probe replies. */
+ DATA(packet)[0] = 1;
+ }
- /* Type 2 probe replies were introduced in protocol 17.3 */
- if ((n->options >> 24) >= 3) {
- uint8_t *data = DATA(packet);
- *data++ = 2;
- uint16_t len16 = htons(len); memcpy(data, &len16, 2); data += 2;
- packet->len = MIN_PROBE_SIZE;
- } else {
- /* Legacy protocol: n won't understand type 2 probe replies. */
- DATA(packet)[0] = 1;
- }
+ /* Temporarily set udp_confirmed, so that the reply is sent
+ back exactly the way it came in. */
- /* 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;
+}
- bool udp_confirmed = n->status.udp_confirmed;
- n->status.udp_confirmed = true;
- send_udppacket(n, packet);
- n->status.udp_confirmed = udp_confirmed;
- } else {
- length_t probelen = len;
- if (DATA(packet)[0] == 2) {
- if (len < 3)
- logger(DEBUG_TRAFFIC, LOG_WARNING, "Received invalid (too short) UDP probe reply from %s (%s)", n->name, n->hostname);
- else {
- uint16_t probelen16; memcpy(&probelen16, DATA(packet) + 1, 2); probelen = ntohs(probelen16);
- }
- }
- logger(DEBUG_TRAFFIC, LOG_INFO, "Got type %d UDP probe reply %d from %s (%s)", DATA(packet)[0], probelen, n->name, n->hostname);
+static void udp_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
+ if(!DATA(packet)[0]) {
+ /* It's a probe request, send back a reply */
+ return send_udp_probe_reply(n, packet, len);
+ }
+
+ if (DATA(packet)[0] == 2) {
+ // It's a type 2 probe reply, use the length field inside the packet
+ uint16_t len16;
+ memcpy(&len16, DATA(packet) + 1, 2);
+ len = ntohs(len16);
+ }
- /* 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;
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Got type %d UDP probe reply %d from %s (%s)", DATA(packet)[0], len, n->name, n->hostname);
- if(udp_discovery) {
- timeout_del(&n->udp_ping_timeout);
- timeout_add(&n->udp_ping_timeout, &udp_probe_timeout_handler, n, &(struct timeval){udp_discovery_timeout, 0});
- }
+ /* 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(probelen >= n->maxmtu + 1) {
- logger(DEBUG_TRAFFIC, LOG_INFO, "Increase in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname);
- n->maxmtu = MTU;
- /* Set mtuprobes to 1 so that try_mtu() doesn't reset maxmtu */
- n->mtuprobes = 1;
- return;
- }
+ if(udp_discovery) {
+ timeout_del(&n->udp_ping_timeout);
+ timeout_add(&n->udp_ping_timeout, &udp_probe_timeout_handler, n, &(struct timeval){udp_discovery_timeout, 0});
+ }
- /* If applicable, raise the minimum supported MTU */
+ if(len > n->maxmtu) {
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Increase in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname);
+ n->minmtu = len;
+ n->maxmtu = MTU;
+ /* Set mtuprobes to 1 so that try_mtu() doesn't reset maxmtu */
+ n->mtuprobes = 1;
+ return;
+ } else if(n->mtuprobes < 0 && len == n->maxmtu) {
+ /* We got a maxmtu sized packet, confirming the PMTU is still valid. */
+ n->mtuprobes = -1;
+ n->mtu_ping_sent = now;
+ }
- if(probelen > n->maxmtu)
- probelen = n->maxmtu;
- if(n->minmtu < probelen) {
- n->minmtu = probelen;
- try_fix_mtu(n);
- }
+ /* If applicable, raise the minimum supported MTU */
+
+ if(n->minmtu < len) {
+ n->minmtu = len;
+ try_fix_mtu(n);
}
}
origlen -= MTU/64 + 20;
}
+ if(inpkt->len > n->maxrecentlen)
+ n->maxrecentlen = inpkt->len;
+
inpkt->priority = 0;
if(!DATA(inpkt)[12] && !DATA(inpkt)[13])
return;
if(udp_discovery && !n->status.udp_confirmed) {
+ n->maxrecentlen = 0;
n->mtuprobes = 0;
n->minmtu = 0;
n->maxmtu = MTU;
/* mtuprobes == 0..19: initial discovery, send bursts with 1 second interval, mtuprobes++
mtuprobes == 20: fix MTU, and go to -1
- mtuprobes == -1: send one >maxmtu probe every pingtimeout */
+ mtuprobes == -1: send one maxmtu and one maxmtu+1 probe every pinginterval
+ mtuprobes ==-2..-3: send one maxmtu probe every second
+ mtuprobes == -4: maxmtu no longer valid, reset minmtu and maxmtu and go to 0 */
struct timeval elapsed;
timersub(&now, &n->mtu_ping_sent, &elapsed);
if(n->mtuprobes != 0 && elapsed.tv_sec == 0 && elapsed.tv_usec < 333333)
return;
} else {
- if(elapsed.tv_sec < pingtimeout)
- return;
+ if(n->mtuprobes < -1) {
+ if(elapsed.tv_sec < 1)
+ return;
+ } else {
+ if(elapsed.tv_sec < pinginterval)
+ return;
+ }
}
n->mtu_ping_sent = now;
try_fix_mtu(n);
+ if(n->mtuprobes < -3) {
+ /* We lost three MTU probes, restart discovery */
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Decrease in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname);
+ n->mtuprobes = 0;
+ n->minmtu = 0;
+ }
+
if(n->mtuprobes < 0) {
/* After the initial discovery, we only send one maxmtu and one
maxmtu+1 probe to detect PMTU increases. */
send_udp_probe_packet(n, n->maxmtu);
- if(n->maxmtu + 1 < MTU)
+ if(n->mtuprobes == -1 && n->maxmtu + 1 < MTU)
send_udp_probe_packet(n, n->maxmtu + 1);
+ n->mtuprobes--;
} else {
/* Before initial discovery begins, set maxmtu to the most likely value.
If it's underestimated, we will correct it after initial discovery. */