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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
c034f85
..
db571ba
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.
+
*/
static void send_mtu_probe_handler(void *data) {
*/
static void send_mtu_probe_handler(void *data) {
@@
-125,13
+129,18
@@
static void send_mtu_probe_handler(void *data) {
timeout = pingtimeout;
}
timeout = pingtimeout;
}
- for(int i = 0; i <
3
+ localdiscovery; i++) {
+ for(int i = 0; i <
4
+ localdiscovery; i++) {
int len;
int len;
- if(n->maxmtu <= n->minmtu)
+ 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;
@@
-140,7
+149,7
@@
static void send_mtu_probe_handler(void *data) {
memset(packet.data, 0, 14);
randomize(packet.data + 14, len - 14);
packet.len = len;
memset(packet.data, 0, 14);
randomize(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;
@@
-199,6
+208,13
@@
static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
/* If we haven't established the PMTU yet, restart the discovery process. */
if(n->mtuprobes > 30) {
/* If we haven't established the PMTU yet, restart the discovery process. */
if(n->mtuprobes > 30) {
+ if (len == n->maxmtu + 8) {
+ logger(DEBUG_TRAFFIC, 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