/*
net_packet.c -- Handles in- and outgoing VPN packets
Copyright (C) 1998-2005 Ivo Timmermans,
- 2000-2010 Guus Sliepen <guus@tinc-vpn.org>
+ 2000-2012 Guus Sliepen <guus@tinc-vpn.org>
+ 2010 Timothy Redaelli <timothy@redaelli.eu>
+ 2010 Brandon Black <blblack@gmail.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#include "ethernet.h"
#include "event.h"
#include "graph.h"
-#include "list.h"
#include "logger.h"
#include "net.h"
#include "netutl.h"
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 at least three, with random sizes between the
+ lower and upper boundaries for the MTU thus far discovered.
+
+ 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.
+
+*/
void send_mtu_probe(node_t *n) {
vpn_packet_t packet;
}
if(n->mtuprobes > 32) {
+ if(!n->minmtu) {
+ n->mtuprobes = 31;
+ timeout = pinginterval;
+ goto end;
+ }
+
ifdebug(TRAFFIC) logger(LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
n->mtuprobes = 1;
n->minmtu = 0;
n->maxmtu = MTU;
}
- if(n->mtuprobes >= 10 && !n->minmtu) {
+ if(n->mtuprobes >= 10 && n->mtuprobes < 32 && !n->minmtu) {
ifdebug(TRAFFIC) logger(LOG_INFO, "No response to MTU probes from %s (%s)", n->name, n->hostname);
- n->mtuprobes = 0;
- return;
+ n->mtuprobes = 31;
}
if(n->mtuprobes == 30 || (n->mtuprobes < 30 && n->minmtu >= n->maxmtu)) {
timeout = pingtimeout;
}
- for(i = 0; i < 3; 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;
- else
+ } else {
len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
+ }
if(len < 64)
len = 64;
memset(packet.data, 0, 14);
RAND_pseudo_bytes(packet.data + 14, len - 14);
packet.len = len;
- packet.priority = 0;
+ if(i >= 4 && 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);
packet->data[0] = 1;
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
+ n->mtuprobes = 1;
+ }
+
if(len > n->maxmtu)
len = n->maxmtu;
if(n->minmtu < len)
n->minmtu = len;
- if(n->mtuprobes > 30)
- n->mtuprobes = 30;
}
}
inpkt->len -= sizeof(inpkt->seqno);
inpkt->seqno = ntohl(inpkt->seqno);
- if(inpkt->seqno != n->received_seqno + 1) {
- if(inpkt->seqno >= n->received_seqno + sizeof(n->late) * 8) {
- logger(LOG_WARNING, "Lost %d packets from %s (%s)",
- inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
-
- memset(n->late, 0, sizeof(n->late));
- } else if (inpkt->seqno <= n->received_seqno) {
- if((n->received_seqno >= sizeof(n->late) * 8 && inpkt->seqno <= n->received_seqno - sizeof(n->late) * 8) || !(n->late[(inpkt->seqno / 8) % sizeof(n->late)] & (1 << inpkt->seqno % 8))) {
- logger(LOG_WARNING, "Got late or replayed packet from %s (%s), seqno %d, last received %d",
- n->name, n->hostname, inpkt->seqno, n->received_seqno);
- return;
+ if(replaywin) {
+ if(inpkt->seqno != n->received_seqno + 1) {
+ if(inpkt->seqno >= n->received_seqno + replaywin * 8) {
+ if(n->farfuture++ < replaywin >> 2) {
+ logger(LOG_WARNING, "Packet from %s (%s) is %d seqs in the future, dropped (%u)",
+ n->name, n->hostname, inpkt->seqno - n->received_seqno - 1, n->farfuture);
+ return;
+ }
+ logger(LOG_WARNING, "Lost %d packets from %s (%s)",
+ inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
+ memset(n->late, 0, replaywin);
+ } else if (inpkt->seqno <= n->received_seqno) {
+ if((n->received_seqno >= replaywin * 8 && inpkt->seqno <= n->received_seqno - replaywin * 8) || !(n->late[(inpkt->seqno / 8) % replaywin] & (1 << inpkt->seqno % 8))) {
+ logger(LOG_WARNING, "Got late or replayed packet from %s (%s), seqno %d, last received %d",
+ n->name, n->hostname, inpkt->seqno, n->received_seqno);
+ return;
+ }
+ } else {
+ for(i = n->received_seqno + 1; i < inpkt->seqno; i++)
+ n->late[(i / 8) % replaywin] |= 1 << i % 8;
}
- } else {
- for(i = n->received_seqno + 1; i < inpkt->seqno; i++)
- n->late[(i / 8) % sizeof(n->late)] |= 1 << i % 8;
}
+
+ n->farfuture = 0;
+ n->late[(inpkt->seqno / 8) % replaywin] &= ~(1 << inpkt->seqno % 8);
}
-
- n->late[(inpkt->seqno / 8) % sizeof(n->late)] &= ~(1 << inpkt->seqno % 8);
if(inpkt->seqno > n->received_seqno)
n->received_seqno = inpkt->seqno;
receive_packet(n, inpkt);
}
-void receive_tcppacket(connection_t *c, char *buffer, int len) {
+void receive_tcppacket(connection_t *c, const char *buffer, int len) {
vpn_packet_t outpkt;
outpkt.len = len;
static int priority = 0;
#endif
int origpriority;
- int sock;
if(!n->status.reachable) {
ifdebug(TRAFFIC) logger(LOG_INFO, "Trying to send UDP packet to unreachable node %s (%s)", n->name, n->hostname);
"No valid key known yet for %s (%s), forwarding via TCP",
n->name, n->hostname);
- if(n->last_req_key + 10 < now) {
+ if(n->last_req_key + 10 <= now) {
send_req_key(n);
n->last_req_key = now;
}
/* Determine which socket we have to use */
- for(sock = 0; sock < listen_sockets; sock++)
- if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family)
- break;
-
- if(sock >= listen_sockets)
- sock = 0; /* If none is available, just use the first and hope for the best. */
+ if(n->address.sa.sa_family != listen_socket[n->sock].sa.sa.sa_family) {
+ for(int sock = 0; sock < listen_sockets; sock++) {
+ if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family) {
+ n->sock = sock;
+ break;
+ }
+ }
+ }
/* Send the packet */
+ struct sockaddr *sa;
+ socklen_t sl;
+ int sock;
+ sockaddr_t broadcast;
+
+ /* Overloaded use of priority field: -1 means local broadcast */
+
+ if(origpriority == -1 && n->prevedge) {
+ sock = rand() % listen_sockets;
+ memset(&broadcast, 0, sizeof broadcast);
+ if(listen_socket[sock].sa.sa.sa_family == AF_INET6) {
+ broadcast.in6.sin6_family = AF_INET6;
+ broadcast.in6.sin6_addr.s6_addr[0x0] = 0xff;
+ broadcast.in6.sin6_addr.s6_addr[0x1] = 0x02;
+ broadcast.in6.sin6_addr.s6_addr[0xf] = 0x01;
+ broadcast.in6.sin6_port = n->prevedge->address.in.sin_port;
+ broadcast.in6.sin6_scope_id = listen_socket[sock].sa.in6.sin6_scope_id;
+ } else {
+ broadcast.in.sin_family = AF_INET;
+ broadcast.in.sin_addr.s_addr = -1;
+ broadcast.in.sin_port = n->prevedge->address.in.sin_port;
+ }
+ sa = &broadcast.sa;
+ sl = SALEN(broadcast.sa);
+ } 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[sock].sa.sa.sa_family == AF_INET) {
+ && listen_socket[n->sock].sa.sa.sa_family == AF_INET) {
priority = origpriority;
ifdebug(TRAFFIC) logger(LOG_DEBUG, "Setting outgoing packet priority to %d", priority);
- if(setsockopt(listen_socket[sock].udp, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
+ if(setsockopt(listen_socket[n->sock].udp, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */
logger(LOG_ERR, "System call `%s' failed: %s", "setsockopt", strerror(errno));
}
#endif
- if(sendto(listen_socket[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(n->mtu >= origlen)
n->mtu = origlen - 1;
} else
- logger(LOG_ERR, "Error sending packet to %s (%s): %s", n->name, n->hostname, sockstrerror(sockerrno));
+ ifdebug(TRAFFIC) logger(LOG_WARNING, "Error sending packet to %s (%s): %s", n->name, n->hostname, sockstrerror(sockerrno));
}
end:
if(n == myself) {
if(overwrite_mac)
memcpy(packet->data, mymac.x, ETH_ALEN);
- write_packet(packet);
+ devops.write(packet);
return;
}
void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
avl_node_t *node;
connection_t *c;
+ node_t *n;
+
+ // Always give ourself a copy of the packet.
+ if(from != myself)
+ send_packet(myself, packet);
+
+ // In TunnelServer mode, do not forward broadcast packets.
+ // The MST might not be valid and create loops.
+ if(tunnelserver || broadcast_mode == BMODE_NONE)
+ return;
ifdebug(TRAFFIC) logger(LOG_INFO, "Broadcasting packet of %d bytes from %s (%s)",
packet->len, from->name, from->hostname);
- if(from != myself) {
- send_packet(myself, packet);
+ switch(broadcast_mode) {
+ // In MST mode, broadcast packets travel via the Minimum Spanning Tree.
+ // This guarantees all nodes receive the broadcast packet, and
+ // usually distributes the sending of broadcast packets over all nodes.
+ case BMODE_MST:
+ for(node = connection_tree->head; node; node = node->next) {
+ c = node->data;
- // In TunnelServer mode, do not forward broadcast packets.
- // The MST might not be valid and create loops.
- if(tunnelserver)
- return;
- }
+ if(c->status.active && c->status.mst && c != from->nexthop->connection)
+ send_packet(c->node, packet);
+ }
+ break;
+
+ // In direct mode, we send copies to each node we know of.
+ // However, this only reaches nodes that can be reached in a single hop.
+ // We don't have enough information to forward broadcast packets in this case.
+ case BMODE_DIRECT:
+ if(from != myself)
+ break;
- for(node = connection_tree->head; node; node = node->next) {
- c = node->data;
+ for(node = node_udp_tree->head; node; node = node->next) {
+ n = node->data;
- if(c->status.active && c->status.mst && c != from->nexthop->connection)
- send_packet(c->node, packet);
+ if(n->status.reachable && ((n->via == myself && n->nexthop == n) || n->via == n))
+ send_packet(n, packet);
+ }
+ break;
+
+ default:
+ break;
}
}
avl_node_t *node;
edge_t *e;
node_t *n = NULL;
+ bool hard = false;
static time_t last_hard_try = 0;
for(node = edge_weight_tree->head; node; node = node->next) {
e = node->data;
+ if(e->to == myself)
+ continue;
+
if(sockaddrcmp_noport(from, &e->address)) {
if(last_hard_try == now)
continue;
- last_hard_try = now;
+ hard = true;
}
- if(!n)
- n = e->to;
-
if(!try_mac(e->to, pkt))
continue;
break;
}
+ if(hard)
+ last_hard_try = now;
+
+ last_hard_try = now;
return n;
}
socklen_t fromlen = sizeof(from);
node_t *n;
- pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
+ pkt.len = recvfrom(listen_socket[sock].udp, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
if(pkt.len < 0) {
if(!sockwouldblock(sockerrno))
return;
}
+ n->sock = sock;
+
receive_udppacket(n, &pkt);
}
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