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Detect increases in PMTU.
[tinc]
/
src
/
net_packet.c
diff --git
a/src/net_packet.c
b/src/net_packet.c
index
2780f51
..
c209248
100644
(file)
--- a/
src/net_packet.c
+++ b/
src/net_packet.c
@@
-70,11
+70,15
@@
bool localdiscovery = false;
mtuprobes == 32: send 1 burst, sleep pingtimeout second
mtuprobes == 33: no response from other side, restart PMTU discovery process
mtuprobes == 32: send 1 burst, sleep pingtimeout second
mtuprobes == 33: no response from other side, restart PMTU discovery process
- Probes are sent in batches of
three, with random sizes between the lower and
- upper boundaries for the MTU thus far discovered.
+ Probes are sent in batches of
at least three, with random sizes between the
+
lower and
upper boundaries for the MTU thus far discovered.
- In case local discovery is enabled, a fourth packet is added to each batch,
+ After the initial discovery, a fourth packet is added to each batch with a
+ size larger than the currently known PMTU, to test if the PMTU has increased.
+
+ In case local discovery is enabled, another packet is added to each batch,
which will be broadcast to the local network.
which will be broadcast to the local network.
+
*/
void send_mtu_probe(node_t *n) {
*/
void send_mtu_probe(node_t *n) {
@@
-126,11
+130,16
@@
void send_mtu_probe(node_t *n) {
timeout = pingtimeout;
}
timeout = pingtimeout;
}
- for(i = 0; i < 3 + localdiscovery; i++) {
- if(n->maxmtu <= n->minmtu)
+ 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;
len = n->maxmtu;
- else
+ } else {
len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
+ }
if(len < 64)
len = 64;
if(len < 64)
len = 64;
@@
-138,7
+147,7
@@
void send_mtu_probe(node_t *n) {
memset(packet.data, 0, 14);
RAND_pseudo_bytes(packet.data + 14, len - 14);
packet.len = len;
memset(packet.data, 0, 14);
RAND_pseudo_bytes(packet.data + 14, len - 14);
packet.len = len;
- if(i >=
3
&& n->mtuprobes <= 10)
+ if(i >=
4
&& n->mtuprobes <= 10)
packet.priority = -1;
else
packet.priority = 0;
packet.priority = -1;
else
packet.priority = 0;
@@
-164,6
+173,13
@@
void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
send_udppacket(n, packet);
} else {
if(n->mtuprobes > 30) {
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
if(n->minmtu)
n->mtuprobes = 30;
else