/*
net_packet.c -- Handles in- and outgoing VPN packets
Copyright (C) 1998-2005 Ivo Timmermans,
- 2000-2018 Guus Sliepen <guus@tinc-vpn.org>
+ 2000-2021 Guus Sliepen <guus@tinc-vpn.org>
2010 Timothy Redaelli <timothy@redaelli.eu>
2010 Brandon Black <blblack@gmail.com>
static void send_udp_probe_packet(node_t *n, int len) {
vpn_packet_t packet;
+
+ if(len > sizeof(packet.data)) {
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Truncating probe length %d to %s (%s)", len, n->name, n->hostname);
+ len = sizeof(packet.data);
+ }
+
packet.offset = DEFAULT_PACKET_OFFSET;
memset(DATA(&packet), 0, 14);
randomize(DATA(&packet) + 14, len - 14);
const length_t minmtu = MAX(n->minmtu, 512);
const float interval = n->maxmtu - minmtu;
- /* The core of the discovery algorithm is this exponential.
- It produces very large probes early in the cycle, and then it very quickly decreases the probe size.
- This reflects the fact that in the most difficult cases, we don't get any feedback for probes that
- are too large, and therefore we need to concentrate on small offsets so that we can quickly converge
- on the precise MTU as we are approaching it.
- The last probe of the cycle is always 1 byte in size - this is to make sure we'll get at least one
- reply per cycle so that we can make progress. */
- const length_t offset = powf(interval, multiplier * cycle_position / (probes_per_cycle - 1));
+ length_t offset = 0;
+
+ /* powf can be underflowed if n->maxmtu is less than 512 due to the minmtu MAX bound */
+ if(interval > 0) {
+ /* The core of the discovery algorithm is this exponential.
+ It produces very large probes early in the cycle, and then it very quickly decreases the probe size.
+ This reflects the fact that in the most difficult cases, we don't get any feedback for probes that
+ are too large, and therefore we need to concentrate on small offsets so that we can quickly converge
+ on the precise MTU as we are approaching it.
+ The last probe of the cycle is always 1 byte in size - this is to make sure we'll get at least one
+ reply per cycle so that we can make progress. */
+ offset = powf(interval, multiplier * cycle_position / (probes_per_cycle - 1));
+ }
length_t maxmtu = n->maxmtu;
send_udp_probe_packet(n, minmtu + offset);
pkt->offset = 2 * sizeof(node_id_t);
from = lookup_node_id(SRCID(pkt));
- if(from && !memcmp(DSTID(pkt), &nullid, sizeof(nullid)) && from->status.sptps) {
+ if(from && from->status.sptps && !memcmp(DSTID(pkt), &nullid, sizeof(nullid))) {
if(sptps_verify_datagram(&from->sptps, DATA(pkt), pkt->len - 2 * sizeof(node_id_t))) {
n = from;
} else {
pkt->len -= pkt->offset;
}
- if(!memcmp(DSTID(pkt), &nullid, sizeof(nullid)) || !relay_enabled) {
+ if(!relay_enabled || !memcmp(DSTID(pkt), &nullid, sizeof(nullid))) {
direct = true;
from = n;
to = myself;