#define MAX_SEQNO 1073741824
+static void try_fix_mtu(node_t *n) {
+ if(n->mtuprobes < 0)
+ return;
+
+ if(n->mtuprobes == 90 || n->minmtu >= n->maxmtu) {
+ if(n->minmtu > n->maxmtu)
+ n->minmtu = n->maxmtu;
+ else
+ n->maxmtu = n->minmtu;
+ n->mtu = n->minmtu;
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes);
+ n->mtuprobes = -1;
+ }
+}
+
static void udp_probe_timeout_handler(void *data) {
node_t *n = data;
if(!n->status.udp_confirmed)
if(probelen >= 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;
+ n->mtuprobes = 30;
return;
}
if(probelen > n->maxmtu)
probelen = n->maxmtu;
- if(n->minmtu < probelen)
+ if(n->minmtu < probelen) {
n->minmtu = probelen;
+ try_fix_mtu(n);
+ }
/* Calculate RTT and bandwidth.
The RTT is the time between the MTU probe burst was sent and the first
n->rtt = diff.tv_sec + diff.tv_usec * 1e-6;
n->probe_time = probe_timestamp;
} else if(n->probe_counter == 3) {
- /* TODO: this will never fire after initial MTU discovery. */
+ /* TODO: this will never fire - we're not sending batches of three anymore. */
struct timeval probe_timestamp_diff;
timersub(&probe_timestamp, &n->probe_time, &probe_timestamp_diff);
n->bandwidth = 2.0 * probelen / (probe_timestamp_diff.tv_sec + probe_timestamp_diff.tv_usec * 1e-6);
n->maxmtu = origlen - 1;
if(n->mtu >= origlen)
n->mtu = origlen - 1;
+ try_fix_mtu(n);
} else
logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending packet to %s (%s): %s", n->name, n->hostname, sockstrerror(sockerrno));
}
relay->maxmtu = len - 1;
if(relay->mtu >= len)
relay->mtu = len - 1;
+ try_fix_mtu(relay);
} else {
logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending UDP SPTPS packet to %s (%s): %s", relay->name, relay->hostname, sockstrerror(sockerrno));
return false;
return;
}
- /* mtuprobes == 0..29: initial discovery, send bursts with 1 second interval, mtuprobes++
- mtuprobes == 30: fix MTU, and go to 31
- mtuprobes == 31: send one >maxmtu probe every pingtimeout */
+ /* mtuprobes == 0..89: initial discovery, send bursts with 1 second interval, mtuprobes++
+ mtuprobes == 90: fix MTU, and go to -1
+ mtuprobes == -1: send one >maxmtu probe every pingtimeout */
struct timeval now;
gettimeofday(&now, NULL);
struct timeval elapsed;
timersub(&now, &n->probe_sent_time, &elapsed);
- if(n->mtuprobes < 31) {
- if(n->mtuprobes != 0 && elapsed.tv_sec < 1)
+ if(n->mtuprobes >= 0) {
+ if(n->mtuprobes != 0 && elapsed.tv_sec == 0 && elapsed.tv_usec < 333333)
return;
} else {
if(elapsed.tv_sec < pingtimeout)
return;
}
- 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(DEBUG_TRAFFIC, LOG_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes);
- n->mtuprobes = 31;
- }
+ try_fix_mtu(n);
int timeout;
- if(n->mtuprobes == 31) {
+ if(n->mtuprobes < 0) {
/* After the initial discovery, we only send one >maxmtu probe
to detect PMTU increases. */
if(n->maxmtu + 8 < MTU)
send_udp_probe_packet(n, n->maxmtu + 8);
} else {
- /* Probes are sent in batches of three, with random sizes between the
+ /* Probes are sent with random sizes between the
lower and upper boundaries for the MTU thus far discovered. */
- for (int i = 0; i < 3; i++) {
- int len = n->maxmtu;
- if(n->minmtu < n->maxmtu)
- len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
+ int len = n->maxmtu;
+ if(n->minmtu < n->maxmtu)
+ len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
+ send_udp_probe_packet(n, MAX(len, 64));
- send_udp_probe_packet(n, MAX(len, 64));
- }
- n->mtuprobes++;
+ if(n->mtuprobes >= 0)
+ n->mtuprobes++;
}
n->probe_counter = 0;