static void send_udppacket(node_t *, vpn_packet_t *);
unsigned replaywin = 16;
+bool localdiscovery = false;
#define MAX_SEQNO 1073741824
-// mtuprobes == 1..30: initial discovery, send bursts with 1 second interval
-// mtuprobes == 31: sleep pinginterval seconds
-// mtuprobes == 32: send 1 burst, sleep pingtimeout second
-// mtuprobes == 33: no response from other side, restart PMTU discovery process
+/* mtuprobes == 1..30: initial discovery, send bursts with 1 second interval
+ mtuprobes == 31: sleep pinginterval seconds
+ 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.
+
+ In case local discovery is enabled, a fourth packet is added to each batch,
+ which will be broadcast to the local network.
+*/
void send_mtu_probe(node_t *n) {
vpn_packet_t packet;
timeout = pingtimeout;
}
- for(i = 0; i < 3; i++) {
+ for(i = 0; i < 3 + localdiscovery; i++) {
if(n->maxmtu <= n->minmtu)
len = n->maxmtu;
else
memset(packet.data, 0, 14);
RAND_pseudo_bytes(packet.data + 14, len - 14);
packet.len = len;
- packet.priority = 0;
+ if(i >= 3 && n->mtuprobes <= 10)
+ packet.priority = -1;
+ else
+ packet.priority = 0;
ifdebug(TRAFFIC) logger(LOG_INFO, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname);
/* Send the packet */
+ struct sockaddr *sa;
+ socklen_t sl;
+ int sock;
+
+ /* Overloaded use of priority field: -1 means local broadcast */
+
+ if(origpriority == -1 && n->prevedge) {
+ struct sockaddr_in in;
+ in.sin_family = AF_INET;
+ in.sin_addr.s_addr = -1;
+ in.sin_port = n->prevedge->address.in.sin_port;
+ sa = (struct sockaddr *)∈
+ sl = sizeof in;
+ sock = 0;
+ } else {
+ if(origpriority == -1)
+ origpriority = 0;
+
+ sa = &(n->address.sa);
+ sl = SALEN(n->address.sa);
+ sock = n->sock;
+ }
+
#if defined(SOL_IP) && defined(IP_TOS)
if(priorityinheritance && origpriority != priority
&& listen_socket[n->sock].sa.sa.sa_family == AF_INET) {
}
#endif
- if(sendto(listen_socket[n->sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa)) < 0 && !sockwouldblock(sockerrno)) {
+ if(sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, sa, sl) < 0 && !sockwouldblock(sockerrno)) {
if(sockmsgsize(sockerrno)) {
if(n->maxmtu >= origlen)
n->maxmtu = origlen - 1;
if(hard)
last_hard_try = now;
+ last_hard_try = now;
return n;
}