/*
net_packet.c -- Handles in- and outgoing VPN packets
Copyright (C) 1998-2005 Ivo Timmermans,
- 2000-2013 Guus Sliepen <guus@tinc-vpn.org>
+ 2000-2014 Guus Sliepen <guus@tinc-vpn.org>
2010 Timothy Redaelli <timothy@redaelli.eu>
2010 Brandon Black <blblack@gmail.com>
#include "utils.h"
#include "xalloc.h"
+#ifndef MAX
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#endif
+
int keylifetime = 0;
#ifdef HAVE_LZO
static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
unsigned replaywin = 16;
bool localdiscovery = true;
+bool udp_discovery = true;
+int udp_discovery_interval = 9;
+int udp_discovery_timeout = 30;
#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
-
- 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.
-
-*/
-
-static void send_mtu_probe_handler(void *data) {
- node_t *n = data;
- int timeout = 1;
-
- n->mtuprobes++;
-
- if(!n->status.reachable || !n->status.validkey) {
- logger(DEBUG_TRAFFIC, LOG_INFO, "Trying to send MTU probe to unreachable or rekeying node %s (%s)", n->name, n->hostname);
- n->mtuprobes = 0;
+static void try_fix_mtu(node_t *n) {
+ if(n->mtuprobes < 0)
return;
- }
- if(n->mtuprobes > 32) {
- if(!n->minmtu) {
- n->mtuprobes = 31;
- timeout = pinginterval;
- goto end;
- }
-
- logger(DEBUG_TRAFFIC, LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname);
- n->status.udp_confirmed = false;
- n->mtuprobes = 1;
- n->minmtu = 0;
- n->maxmtu = MTU;
- }
-
- if(n->mtuprobes >= 10 && n->mtuprobes < 32 && !n->minmtu) {
- logger(DEBUG_TRAFFIC, LOG_INFO, "No response to MTU probes from %s (%s)", n->name, n->hostname);
- n->mtuprobes = 31;
- }
-
- if(n->mtuprobes == 30 || (n->mtuprobes < 30 && n->minmtu >= n->maxmtu)) {
+ if(n->mtuprobes == 20 || 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;
- }
-
- if(n->mtuprobes == 31) {
- timeout = pinginterval;
- goto end;
- } else if(n->mtuprobes == 32) {
- timeout = pingtimeout;
+ n->mtuprobes = -1;
}
-
- for(int i = 0; i < 4 + localdiscovery; i++) {
- int len;
-
- 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 {
- len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu);
- }
-
- if(len < 64)
- len = 64;
-
- vpn_packet_t packet;
- memset(packet.data, 0, 14);
- randomize(packet.data + 14, len - 14);
- packet.len = len;
- packet.priority = 0;
- n->status.send_locally = i >= 4 && n->mtuprobes <= 10 && n->prevedge;
-
- logger(DEBUG_TRAFFIC, LOG_INFO, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname);
-
- send_udppacket(n, &packet);
- }
-
- n->status.send_locally = false;
- n->probe_counter = 0;
- gettimeofday(&n->probe_time, NULL);
-
- /* Calculate the packet loss of incoming traffic by comparing the rate of
- packets received to the rate with which the sequence number has increased.
- */
-
- if(n->received > n->prev_received)
- n->packetloss = 1.0 - (n->received - n->prev_received) / (float)(n->received_seqno - n->prev_received_seqno);
- else
- n->packetloss = n->received_seqno <= n->prev_received_seqno;
-
- n->prev_received_seqno = n->received_seqno;
- n->prev_received = n->received;
-
-end:
- timeout_set(&n->mtutimeout, &(struct timeval){timeout, rand() % 100000});
}
-void send_mtu_probe(node_t *n) {
- timeout_add(&n->mtutimeout, send_mtu_probe_handler, n, &(struct timeval){1, 0});
- send_mtu_probe_handler(n);
+static void udp_probe_timeout_handler(void *data) {
+ node_t *n = data;
+ if(!n->status.udp_confirmed)
+ return;
+
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Too much time has elapsed since last UDP ping response from %s (%s), stopping UDP communication", n->name, n->hostname);
+ n->status.udp_confirmed = false;
+ n->mtuprobes = 0;
+ n->minmtu = 0;
+ n->maxmtu = MTU;
}
-static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
- if(!packet->data[0]) {
- logger(DEBUG_TRAFFIC, LOG_INFO, "Got MTU probe request %d from %s (%s)", packet->len, n->name, n->hostname);
+static void udp_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
+ if(!DATA(packet)[0]) {
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Got UDP probe request %d from %s (%s)", packet->len, n->name, n->hostname);
/* It's a probe request, send back a reply */
/* Type 2 probe replies were introduced in protocol 17.3 */
- if ((n->options >> 24) == 3) {
- uint8_t* data = packet->data;
+ if ((n->options >> 24) >= 3) {
+ uint8_t *data = DATA(packet);
*data++ = 2;
uint16_t len16 = htons(len); memcpy(data, &len16, 2); data += 2;
struct timeval now;
gettimeofday(&now, NULL);
uint32_t sec = htonl(now.tv_sec); memcpy(data, &sec, 4); data += 4;
uint32_t usec = htonl(now.tv_usec); memcpy(data, &usec, 4); data += 4;
- packet->len = data - packet->data;
+ packet->len -= 10;
} else {
/* Legacy protocol: n won't understand type 2 probe replies. */
- packet->data[0] = 1;
+ DATA(packet)[0] = 1;
}
/* Temporarily set udp_confirmed, so that the reply is sent
n->status.udp_confirmed = udp_confirmed;
} else {
length_t probelen = len;
- if (packet->data[0] == 2) {
+ if (DATA(packet)[0] == 2) {
if (len < 3)
- logger(DEBUG_TRAFFIC, LOG_WARNING, "Received invalid (too short) MTU probe reply from %s (%s)", n->name, n->hostname);
+ logger(DEBUG_TRAFFIC, LOG_WARNING, "Received invalid (too short) UDP probe reply from %s (%s)", n->name, n->hostname);
else {
- uint16_t probelen16; memcpy(&probelen16, packet->data + 1, 2); probelen = ntohs(probelen16);
+ uint16_t probelen16; memcpy(&probelen16, DATA(packet) + 1, 2); probelen = ntohs(probelen16);
}
}
- logger(DEBUG_TRAFFIC, LOG_INFO, "Got type %d MTU probe reply %d from %s (%s)", packet->data[0], probelen, n->name, n->hostname);
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Got type %d UDP probe reply %d from %s (%s)", DATA(packet)[0], probelen, n->name, n->hostname);
/* It's a valid reply: now we know bidirectional communication
is possible using the address and socket that the reply
packet used. */
-
n->status.udp_confirmed = true;
- /* If we haven't established the PMTU yet, restart the discovery process. */
-
- if(n->mtuprobes > 30) {
- 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;
- return;
- }
+ if(udp_discovery) {
+ timeout_del(&n->udp_ping_timeout);
+ timeout_add(&n->udp_ping_timeout, &udp_probe_timeout_handler, n, &(struct timeval){udp_discovery_timeout, 0});
+ }
- if(n->minmtu)
- n->mtuprobes = 30;
- else
- n->mtuprobes = 1;
+ if(probelen >= n->maxmtu + 1) {
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Increase in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname);
+ n->maxmtu = MTU;
+ n->mtuprobes = 0;
+ return;
}
/* If applicable, raise the minimum supported MTU */
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.
+ /* Calculate RTT.
The RTT is the time between the MTU probe burst was sent and the first
- reply is received. The bandwidth is measured using the time between the
- arrival of the first and third probe reply (or type 2 probe requests).
+ reply is received.
*/
struct timeval now, diff;
timersub(&now, &n->probe_time, &diff);
struct timeval probe_timestamp = now;
- if (packet->data[0] == 2 && packet->len >= 11) {
- uint32_t sec; memcpy(&sec, packet->data + 3, 4);
- uint32_t usec; memcpy(&usec, packet->data + 7, 4);
+ if (DATA(packet)[0] == 2 && packet->len >= 11) {
+ uint32_t sec; memcpy(&sec, DATA(packet) + 3, 4);
+ uint32_t usec; memcpy(&usec, DATA(packet) + 7, 4);
probe_timestamp.tv_sec = ntohl(sec);
probe_timestamp.tv_usec = ntohl(usec);
}
if(n->probe_counter == 1) {
n->rtt = diff.tv_sec + diff.tv_usec * 1e-6;
n->probe_time = probe_timestamp;
- } else if(n->probe_counter == 3) {
- 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);
- logger(DEBUG_TRAFFIC, LOG_DEBUG, "%s (%s) RTT %.2f ms, burst bandwidth %.3f Mbit/s, rx packet loss %.2f %%", n->name, n->hostname, n->rtt * 1e3, n->bandwidth * 8e-6, n->packetloss * 1e2);
+ logger(DEBUG_TRAFFIC, LOG_DEBUG, "%s (%s) RTT %.2f ms, rx packet loss %.2f %%", n->name, n->hostname, n->rtt * 1e3, n->packetloss * 1e2);
}
}
}
static bool try_mac(node_t *n, const vpn_packet_t *inpkt) {
if(n->status.sptps)
- return sptps_verify_datagram(&n->sptps, (char *)&inpkt->seqno, inpkt->len);
+ return sptps_verify_datagram(&n->sptps, DATA(inpkt), inpkt->len);
- if(!digest_active(n->indigest) || inpkt->len < sizeof inpkt->seqno + digest_length(n->indigest))
+#ifdef DISABLE_LEGACY
+ return false;
+#else
+ if(!digest_active(n->indigest) || inpkt->len < sizeof(seqno_t) + digest_length(n->indigest))
return false;
- return digest_verify(n->indigest, &inpkt->seqno, inpkt->len - digest_length(n->indigest), (const char *)&inpkt->seqno + inpkt->len - digest_length(n->indigest));
+ return digest_verify(n->indigest, SEQNO(inpkt), inpkt->len - digest_length(n->indigest), DATA(inpkt) + inpkt->len - digest_length(n->indigest));
+#endif
}
-static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
+static bool receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
vpn_packet_t pkt1, pkt2;
vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
int nextpkt = 0;
size_t outlen;
+ pkt1.offset = DEFAULT_PACKET_OFFSET;
+ pkt2.offset = DEFAULT_PACKET_OFFSET;
if(n->status.sptps) {
if(!n->sptps.state) {
} else {
logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet", n->name, n->hostname);
}
- return;
+ return false;
}
- sptps_receive_data(&n->sptps, (char *)&inpkt->seqno, inpkt->len);
- return;
+ inpkt->offset += 2 * sizeof(node_id_t);
+ if(!sptps_receive_data(&n->sptps, DATA(inpkt), inpkt->len - 2 * sizeof(node_id_t))) {
+ logger(DEBUG_TRAFFIC, LOG_ERR, "Got bad packet from %s (%s)", n->name, n->hostname);
+ return false;
+ }
+ return true;
}
+#ifdef DISABLE_LEGACY
+ return false;
+#else
if(!n->status.validkey) {
logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet", n->name, n->hostname);
- return;
+ return false;
}
/* Check packet length */
- if(inpkt->len < sizeof inpkt->seqno + digest_length(n->indigest)) {
+ if(inpkt->len < sizeof(seqno_t) + digest_length(n->indigest)) {
logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got too short packet from %s (%s)",
n->name, n->hostname);
- return;
+ return false;
}
+ /* It's a legacy UDP packet, the data starts after the seqno */
+
+ inpkt->offset += sizeof(seqno_t);
+
/* Check the message authentication code */
if(digest_active(n->indigest)) {
inpkt->len -= digest_length(n->indigest);
- if(!digest_verify(n->indigest, &inpkt->seqno, inpkt->len, (const char *)&inpkt->seqno + inpkt->len)) {
+ if(!digest_verify(n->indigest, SEQNO(inpkt), inpkt->len, SEQNO(inpkt) + inpkt->len)) {
logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got unauthenticated packet from %s (%s)", n->name, n->hostname);
- return;
+ return false;
}
}
/* Decrypt the packet */
vpn_packet_t *outpkt = pkt[nextpkt++];
outlen = MAXSIZE;
- if(!cipher_decrypt(n->incipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
+ if(!cipher_decrypt(n->incipher, SEQNO(inpkt), inpkt->len, SEQNO(outpkt), &outlen, true)) {
logger(DEBUG_TRAFFIC, LOG_DEBUG, "Error decrypting packet from %s (%s)", n->name, n->hostname);
- return;
+ return false;
}
outpkt->len = outlen;
/* Check the sequence number */
- inpkt->len -= sizeof inpkt->seqno;
- inpkt->seqno = ntohl(inpkt->seqno);
+ seqno_t seqno;
+ memcpy(&seqno, SEQNO(inpkt), sizeof seqno);
+ seqno = ntohl(seqno);
+ inpkt->len -= sizeof seqno;
if(replaywin) {
- if(inpkt->seqno != n->received_seqno + 1) {
- if(inpkt->seqno >= n->received_seqno + replaywin * 8) {
+ if(seqno != n->received_seqno + 1) {
+ if(seqno >= n->received_seqno + replaywin * 8) {
if(n->farfuture++ < replaywin >> 2) {
logger(DEBUG_ALWAYS, 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;
+ n->name, n->hostname, seqno - n->received_seqno - 1, n->farfuture);
+ return false;
}
logger(DEBUG_ALWAYS, LOG_WARNING, "Lost %d packets from %s (%s)",
- inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
+ 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))) {
+ } else if (seqno <= n->received_seqno) {
+ if((n->received_seqno >= replaywin * 8 && seqno <= n->received_seqno - replaywin * 8) || !(n->late[(seqno / 8) % replaywin] & (1 << seqno % 8))) {
logger(DEBUG_ALWAYS, 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;
+ n->name, n->hostname, seqno, n->received_seqno);
+ return false;
}
} else {
- for(int i = n->received_seqno + 1; i < inpkt->seqno; i++)
+ for(int i = n->received_seqno + 1; i < seqno; i++)
n->late[(i / 8) % replaywin] |= 1 << i % 8;
}
}
n->farfuture = 0;
- n->late[(inpkt->seqno / 8) % replaywin] &= ~(1 << inpkt->seqno % 8);
+ n->late[(seqno / 8) % replaywin] &= ~(1 << seqno % 8);
}
- if(inpkt->seqno > n->received_seqno)
- n->received_seqno = inpkt->seqno;
+ if(seqno > n->received_seqno)
+ n->received_seqno = seqno;
n->received++;
if(n->incompression) {
vpn_packet_t *outpkt = pkt[nextpkt++];
- if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, n->incompression)) < 0) {
+ if((outpkt->len = uncompress_packet(DATA(outpkt), DATA(inpkt), inpkt->len, n->incompression)) < 0) {
logger(DEBUG_TRAFFIC, LOG_ERR, "Error while uncompressing packet from %s (%s)",
n->name, n->hostname);
- return;
+ return false;
}
inpkt = outpkt;
inpkt->priority = 0;
- if(!inpkt->data[12] && !inpkt->data[13])
- mtu_probe_h(n, inpkt, origlen);
+ if(!DATA(inpkt)[12] && !DATA(inpkt)[13])
+ udp_probe_h(n, inpkt, origlen);
else
receive_packet(n, inpkt);
+ return true;
+#endif
}
void receive_tcppacket(connection_t *c, const char *buffer, int len) {
vpn_packet_t outpkt;
+ outpkt.offset = DEFAULT_PACKET_OFFSET;
- if(len > sizeof outpkt.data)
+ if(len > sizeof outpkt.data - outpkt.offset)
return;
outpkt.len = len;
outpkt.priority = 0;
else
outpkt.priority = -1;
- memcpy(outpkt.data, buffer, len);
+ memcpy(DATA(&outpkt), buffer, len);
receive_packet(c->node, &outpkt);
}
static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
- if(!n->status.validkey) {
- logger(DEBUG_TRAFFIC, LOG_INFO, "No valid key known yet for %s (%s)", n->name, n->hostname);
- if(!n->status.waitingforkey)
- send_req_key(n);
- else if(n->last_req_key + 10 < now.tv_sec) {
- logger(DEBUG_ALWAYS, LOG_DEBUG, "No key from %s after 10 seconds, restarting SPTPS", n->name);
- sptps_stop(&n->sptps);
- n->status.waitingforkey = false;
- send_req_key(n);
- }
+ if(!n->status.validkey && !n->connection)
return;
- }
uint8_t type = 0;
int offset = 0;
- if(!(origpkt->data[12] | origpkt->data[13])) {
- sptps_send_record(&n->sptps, PKT_PROBE, (char *)origpkt->data, origpkt->len);
+ if(!(DATA(origpkt)[12] | DATA(origpkt)[13])) {
+ sptps_send_record(&n->sptps, PKT_PROBE, (char *)DATA(origpkt), origpkt->len);
return;
}
vpn_packet_t outpkt;
if(n->outcompression) {
- int len = compress_packet(outpkt.data + offset, origpkt->data + offset, origpkt->len - offset, n->outcompression);
+ outpkt.offset = 0;
+ int len = compress_packet(DATA(&outpkt) + offset, DATA(origpkt) + offset, origpkt->len - offset, n->outcompression);
if(len < 0) {
logger(DEBUG_TRAFFIC, LOG_ERR, "Error while compressing packet to %s (%s)", n->name, n->hostname);
} else if(len < origpkt->len - offset) {
}
}
- sptps_send_record(&n->sptps, type, (char *)origpkt->data + offset, origpkt->len - offset);
+ /* If we have a direct metaconnection to n, and we can't use UDP, then
+ don't bother with SPTPS and just use a "plaintext" PACKET message.
+ We don't really care about end-to-end security since we're not
+ sending the message through any intermediate nodes. */
+ if(n->connection && origpkt->len > n->minmtu)
+ send_tcppacket(n->connection, origpkt);
+ else
+ sptps_send_record(&n->sptps, type, DATA(origpkt) + offset, origpkt->len - offset);
return;
}
size_t outlen;
#if defined(SOL_IP) && defined(IP_TOS)
static int priority = 0;
-#endif
int origpriority = origpkt->priority;
+#endif
+
+ pkt1.offset = DEFAULT_PACKET_OFFSET;
+ pkt2.offset = DEFAULT_PACKET_OFFSET;
if(!n->status.reachable) {
logger(DEBUG_TRAFFIC, LOG_INFO, "Trying to send UDP packet to unreachable node %s (%s)", n->name, n->hostname);
if(n->status.sptps)
return send_sptps_packet(n, origpkt);
+#ifdef DISABLE_LEGACY
+ return;
+#else
/* Make sure we have a valid key */
if(!n->status.validkey) {
logger(DEBUG_TRAFFIC, LOG_INFO,
"No valid key known yet for %s (%s), forwarding via TCP",
n->name, n->hostname);
-
- if(n->last_req_key + 10 <= now.tv_sec) {
- send_req_key(n);
- n->last_req_key = now.tv_sec;
- }
-
send_tcppacket(n->nexthop->connection, origpkt);
-
return;
}
- if(n->options & OPTION_PMTU_DISCOVERY && inpkt->len > n->minmtu && (inpkt->data[12] | inpkt->data[13])) {
+ if(n->options & OPTION_PMTU_DISCOVERY && inpkt->len > n->minmtu && (DATA(inpkt)[12] | DATA(inpkt)[13])) {
logger(DEBUG_TRAFFIC, LOG_INFO,
"Packet for %s (%s) larger than minimum MTU, forwarding via %s",
n->name, n->hostname, n != n->nexthop ? n->nexthop->name : "TCP");
if(n->outcompression) {
outpkt = pkt[nextpkt++];
- if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->outcompression)) < 0) {
+ if((outpkt->len = compress_packet(DATA(outpkt), DATA(inpkt), inpkt->len, n->outcompression)) < 0) {
logger(DEBUG_TRAFFIC, LOG_ERR, "Error while compressing packet to %s (%s)",
n->name, n->hostname);
return;
/* Add sequence number */
- inpkt->seqno = htonl(++(n->sent_seqno));
- inpkt->len += sizeof inpkt->seqno;
+ seqno_t seqno = htonl(++(n->sent_seqno));
+ memcpy(SEQNO(inpkt), &seqno, sizeof seqno);
+ inpkt->len += sizeof seqno;
/* Encrypt the packet */
outpkt = pkt[nextpkt++];
outlen = MAXSIZE;
- if(!cipher_encrypt(n->outcipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
+ if(!cipher_encrypt(n->outcipher, SEQNO(inpkt), inpkt->len, SEQNO(outpkt), &outlen, true)) {
logger(DEBUG_TRAFFIC, LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
goto end;
}
/* Add the message authentication code */
if(digest_active(n->outdigest)) {
- if(!digest_create(n->outdigest, &inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + inpkt->len)) {
+ if(!digest_create(n->outdigest, SEQNO(inpkt), inpkt->len, SEQNO(inpkt) + inpkt->len)) {
logger(DEBUG_TRAFFIC, LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
goto end;
}
}
#endif
- if(sendto(listen_socket[sock].udp.fd, (char *) &inpkt->seqno, inpkt->len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
+ if(sendto(listen_socket[sock].udp.fd, SEQNO(inpkt), inpkt->len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
if(sockmsgsize(sockerrno)) {
if(n->maxmtu >= origlen)
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));
}
end:
origpkt->len = origlen;
+#endif
}
-bool send_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
- node_t *to = handle;
+static bool send_sptps_data_priv(node_t *to, node_t *from, int type, const void *data, size_t len) {
+ node_t *relay = (to->via != myself && (type == PKT_PROBE || (len - SPTPS_DATAGRAM_OVERHEAD) <= to->via->minmtu)) ? to->via : to->nexthop;
+ bool direct = from == myself && to == relay;
+ bool relay_supported = (relay->options >> 24) >= 4;
+ bool tcponly = (myself->options | relay->options) & OPTION_TCPONLY;
- /* Send it via TCP if it is a handshake packet, TCPOnly is in use, or this packet is larger than the MTU. */
+ /* Send it via TCP if it is a handshake packet, TCPOnly is in use, this is a relay packet that the other node cannot understand, or this packet is larger than the MTU.
+ TODO: When relaying, the original sender does not know the end-to-end PMTU (it only knows the PMTU of the first hop).
+ This can lead to scenarios where large packets are sent over UDP to relay, but then relay has no choice but fall back to TCP. */
- if(type >= SPTPS_HANDSHAKE || ((myself->options | to->options) & OPTION_TCPONLY) || (type != PKT_PROBE && (len - SPTPS_DATAGRAM_OVERHEAD) > to->minmtu)) {
+ if(type == SPTPS_HANDSHAKE || tcponly || (!direct && !relay_supported) || (type != PKT_PROBE && (len - SPTPS_DATAGRAM_OVERHEAD) > relay->minmtu)) {
char buf[len * 4 / 3 + 5];
b64encode(data, buf, len);
/* If no valid key is known yet, send the packets using ANS_KEY requests,
to ensure we get to learn the reflexive UDP address. */
- if(!to->status.validkey) {
+ if(from == myself && !to->status.validkey) {
to->incompression = myself->incompression;
- return send_request(to->nexthop->connection, "%d %s %s %s -1 -1 -1 %d", ANS_KEY, myself->name, to->name, buf, to->incompression);
+ return send_request(to->nexthop->connection, "%d %s %s %s -1 -1 -1 %d", ANS_KEY, from->name, to->name, buf, to->incompression);
} else {
- return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_SPTPS, buf);
+ return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, from->name, to->name, REQ_SPTPS, buf);
}
}
- /* Otherwise, send the packet via UDP */
+ size_t overhead = 0;
+ if(relay_supported) overhead += sizeof to->id + sizeof from->id;
+ char buf[len + overhead]; char* buf_ptr = buf;
+ if(relay_supported) {
+ if(direct) {
+ /* Inform the recipient that this packet was sent directly. */
+ node_id_t nullid = {};
+ memcpy(buf_ptr, &nullid, sizeof nullid); buf_ptr += sizeof nullid;
+ } else {
+ memcpy(buf_ptr, &to->id, sizeof to->id); buf_ptr += sizeof to->id;
+ }
+ memcpy(buf_ptr, &from->id, sizeof from->id); buf_ptr += sizeof from->id;
+
+ }
+ /* TODO: if this copy turns out to be a performance concern, change sptps_send_record() to add some "pre-padding" to the buffer and use that instead */
+ memcpy(buf_ptr, data, len); buf_ptr += len;
const sockaddr_t *sa = NULL;
int sock;
-
- if(to->status.send_locally)
- choose_local_address(to, &sa, &sock);
+ if(relay->status.send_locally)
+ choose_local_address(relay, &sa, &sock);
if(!sa)
- choose_udp_address(to, &sa, &sock);
-
- if(sendto(listen_socket[sock].udp.fd, data, len, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
+ choose_udp_address(relay, &sa, &sock);
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Sending packet from %s (%s) to %s (%s) via %s (%s)", from->name, from->hostname, to->name, to->hostname, relay->name, relay->hostname);
+ if(sendto(listen_socket[sock].udp.fd, buf, buf_ptr - buf, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
if(sockmsgsize(sockerrno)) {
// Compensate for SPTPS overhead
len -= SPTPS_DATAGRAM_OVERHEAD;
- if(to->maxmtu >= len)
- to->maxmtu = len - 1;
- if(to->mtu >= len)
- to->mtu = len - 1;
+ if(relay->maxmtu >= len)
+ 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", to->name, to->hostname, sockstrerror(sockerrno));
+ logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending UDP SPTPS packet to %s (%s): %s", relay->name, relay->hostname, sockstrerror(sockerrno));
return false;
}
}
return true;
}
-bool receive_sptps_record(void *handle, uint8_t type, const char *data, uint16_t len) {
+bool send_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
+ return send_sptps_data_priv(handle, myself, type, data, len);
+}
+
+bool receive_sptps_record(void *handle, uint8_t type, const void *data, uint16_t len) {
node_t *from = handle;
if(type == SPTPS_HANDSHAKE) {
}
vpn_packet_t inpkt;
+ inpkt.offset = DEFAULT_PACKET_OFFSET;
if(type == PKT_PROBE) {
inpkt.len = len;
- memcpy(inpkt.data, data, len);
- mtu_probe_h(from, &inpkt, len);
+ memcpy(DATA(&inpkt), data, len);
+ udp_probe_h(from, &inpkt, len);
return true;
}
int offset = (type & PKT_MAC) ? 0 : 14;
if(type & PKT_COMPRESSED) {
- length_t ulen = uncompress_packet(inpkt.data + offset, (const uint8_t *)data, len, from->incompression);
+ length_t ulen = uncompress_packet(DATA(&inpkt) + offset, (const uint8_t *)data, len, from->incompression);
if(ulen < 0) {
return false;
} else {
if(inpkt.len > MAXSIZE)
abort();
} else {
- memcpy(inpkt.data + offset, data, len);
+ memcpy(DATA(&inpkt) + offset, data, len);
inpkt.len = len + offset;
}
/* Generate the Ethernet packet type if necessary */
if(offset) {
- switch(inpkt.data[14] >> 4) {
+ switch(DATA(&inpkt)[14] >> 4) {
case 4:
- inpkt.data[12] = 0x08;
- inpkt.data[13] = 0x00;
+ DATA(&inpkt)[12] = 0x08;
+ DATA(&inpkt)[13] = 0x00;
break;
case 6:
- inpkt.data[12] = 0x86;
- inpkt.data[13] = 0xDD;
+ DATA(&inpkt)[12] = 0x86;
+ DATA(&inpkt)[13] = 0xDD;
break;
default:
logger(DEBUG_TRAFFIC, LOG_ERR,
"Unknown IP version %d while reading packet from %s (%s)",
- inpkt.data[14] >> 4, from->name, from->hostname);
+ DATA(&inpkt)[14] >> 4, from->name, from->hostname);
return false;
}
}
return true;
}
+// This function tries to get SPTPS keys, if they aren't already known.
+// This function makes no guarantees - it is up to the caller to check the node's state to figure out if the keys are available.
+static void try_sptps(node_t *n) {
+ if(n->status.validkey)
+ return;
+
+ logger(DEBUG_TRAFFIC, LOG_INFO, "No valid key known yet for %s (%s)", n->name, n->hostname);
+
+ if(!n->status.waitingforkey)
+ send_req_key(n);
+ else if(n->last_req_key + 10 < now.tv_sec) {
+ logger(DEBUG_ALWAYS, LOG_DEBUG, "No key from %s after 10 seconds, restarting SPTPS", n->name);
+ sptps_stop(&n->sptps);
+ n->status.waitingforkey = false;
+ send_req_key(n);
+ }
+
+ return;
+}
+
+static void send_udp_probe_packet(node_t *n, int len) {
+ vpn_packet_t packet;
+ packet.offset = DEFAULT_PACKET_OFFSET;
+ memset(DATA(&packet), 0, 14);
+ randomize(DATA(&packet) + 14, len - 14);
+ packet.len = len;
+ packet.priority = 0;
+
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Sending UDP probe length %d to %s (%s)", len, n->name, n->hostname);
+
+ send_udppacket(n, &packet);
+}
+
+// This function tries to establish a UDP tunnel to a node so that packets can be sent.
+// If a tunnel is already established, it makes sure it stays up.
+// This function makes no guarantees - it is up to the caller to check the node's state to figure out if UDP is usable.
+static void try_udp(node_t* n) {
+ if(!udp_discovery)
+ return;
+
+ struct timeval now;
+ gettimeofday(&now, NULL);
+ struct timeval ping_tx_elapsed;
+ timersub(&now, &n->udp_ping_sent, &ping_tx_elapsed);
+
+ if(ping_tx_elapsed.tv_sec >= udp_discovery_interval) {
+ send_udp_probe_packet(n, MAX(n->minmtu, 16));
+ n->udp_ping_sent = now;
+
+ if(localdiscovery && !n->status.udp_confirmed && n->prevedge) {
+ n->status.send_locally = true;
+ send_udp_probe_packet(n, 16);
+ n->status.send_locally = false;
+ }
+ }
+}
+
+// This function tries to determines the MTU of a node.
+// By calling this function repeatedly, n->minmtu will be progressively increased, and at some point, n->mtu will be fixed to n->minmtu.
+// If the MTU is already fixed, this function checks if it can be increased.
+static void try_mtu(node_t *n) {
+ if(!(n->options & OPTION_PMTU_DISCOVERY))
+ return;
+
+ if(udp_discovery && !n->status.udp_confirmed) {
+ n->mtuprobes = 0;
+ n->minmtu = 0;
+ n->maxmtu = MTU;
+ return;
+ }
+
+ /* mtuprobes == 0..19: initial discovery, send bursts with 1 second interval, mtuprobes++
+ mtuprobes == 20: 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 >= 0) {
+ if(n->mtuprobes != 0 && elapsed.tv_sec == 0 && elapsed.tv_usec < 333333)
+ return;
+ } else {
+ if(elapsed.tv_sec < pingtimeout)
+ return;
+ }
+
+ try_fix_mtu(n);
+
+ int timeout;
+ if(n->mtuprobes < 0) {
+ /* After the initial discovery, we only send one >maxmtu probe
+ to detect PMTU increases. */
+ if(n->maxmtu + 1 < MTU)
+ send_udp_probe_packet(n, n->maxmtu + 1);
+ } else {
+ /* Decreasing the number of probes per cycle might make the algorithm react faster to lost packets,
+ but it will typically increase convergence time in the no-loss case. */
+ const length_t probes_per_cycle = 8;
+
+ /* This magic value was determined using math simulations.
+ It will result in a 1329-byte first probe, followed (if there was a reply) by a 1407-byte probe.
+ Since 1407 is just below the range of tinc MTUs over typical networks,
+ this fine-tuning allows tinc to cover a lot of ground very quickly. */
+ const float multiplier = 0.97;
+
+ const float cycle_position = probes_per_cycle - (n->mtuprobes % probes_per_cycle) - 1;
+ 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));
+
+ send_udp_probe_packet(n, minmtu + offset);
+ if(n->mtuprobes >= 0)
+ n->mtuprobes++;
+ }
+
+ n->probe_counter = 0;
+ n->probe_sent_time = now;
+ n->probe_time = now;
+
+ /* Calculate the packet loss of incoming traffic by comparing the rate of
+ packets received to the rate with which the sequence number has increased.
+ TODO: this is unrelated to PMTU discovery - it should be moved elsewhere.
+ */
+
+ if(n->received > n->prev_received)
+ n->packetloss = 1.0 - (n->received - n->prev_received) / (float)(n->received_seqno - n->prev_received_seqno);
+ else
+ n->packetloss = n->received_seqno <= n->prev_received_seqno;
+
+ n->prev_received_seqno = n->received_seqno;
+ n->prev_received = n->received;
+}
+
+// This function tries to establish a tunnel to a node (or its relay) so that packets can be sent (e.g. get SPTPS keys).
+// If a tunnel is already established, it tries to improve it (e.g. by trying to establish a UDP tunnel instead of TCP).
+// This function makes no guarantees - it is up to the caller to check the node's state to figure out if TCP and/or UDP is usable.
+// By calling this function repeatedly, the tunnel is gradually improved until we hit the wall imposed by the underlying network environment.
+// It is recommended to call this function every time a packet is sent (or intended to be sent) to a node,
+// so that the tunnel keeps improving as packets flow, and then gracefully downgrades itself as it goes idle.
+static void try_tx(node_t *n) {
+ /* If n is a TCP-only neighbor, we'll only use "cleartext" PACKET
+ messages anyway, so there's no need for SPTPS at all. Otherwise, get the keys. */
+ if(n->status.sptps && !(n->connection && ((myself->options | n->options) & OPTION_TCPONLY))) {
+ try_sptps(n);
+ if (!n->status.validkey)
+ return;
+ }
+
+ node_t *via = (n->via == myself) ? n->nexthop : n->via;
+
+ if((myself->options | via->options) & OPTION_TCPONLY)
+ return;
+
+ if(!n->status.sptps && !via->status.validkey && via->last_req_key + 10 <= now.tv_sec) {
+ send_req_key(via);
+ via->last_req_key = now.tv_sec;
+ } else if(via == n || !n->status.sptps || (via->options >> 24) >= 4) {
+ try_udp(via);
+ try_mtu(via);
+ }
+
+ /* If we don't know how to reach "via" yet, then try to reach it through a relay. */
+ if(n->status.sptps && !via->status.udp_confirmed && via->nexthop != via && (via->nexthop->options >> 24) >= 4)
+ try_tx(via->nexthop);
+}
+
/*
send a packet to the given vpn ip.
*/
if(n == myself) {
if(overwrite_mac)
- memcpy(packet->data, mymac.x, ETH_ALEN);
+ memcpy(DATA(packet), mymac.x, ETH_ALEN);
n->out_packets++;
n->out_bytes += packet->len;
devops.write(packet);
if(n->status.sptps) {
send_sptps_packet(n, packet);
- return;
+ goto end;
}
via = (packet->priority == -1 || n->via == myself) ? n->nexthop : n->via;
terminate_connection(via->connection, true);
} else
send_udppacket(via, packet);
+
+end:
+ /* Try to improve the tunnel.
+ Note that we do this *after* we send the packet because sending actual packets take priority
+ with regard to the send buffer space and latency. */
+ try_tx(n);
}
/* Broadcast a packet using the minimum spanning tree */
listen_socket_t *ls = data;
vpn_packet_t pkt;
char *hostname;
- sockaddr_t from = {{0}};
- socklen_t fromlen = sizeof from;
- node_t *n;
- int len;
+ node_id_t nullid = {};
+ sockaddr_t addr = {};
+ socklen_t addrlen = sizeof addr;
+ node_t *from, *to;
+ bool direct = false;
- len = recvfrom(ls->udp.fd, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
+ pkt.offset = 0;
+ int len = recvfrom(ls->udp.fd, DATA(&pkt), MAXSIZE, 0, &addr.sa, &addrlen);
if(len <= 0 || len > MAXSIZE) {
if(!sockwouldblock(sockerrno))
pkt.len = len;
- sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
+ sockaddrunmap(&addr); /* Some braindead IPv6 implementations do stupid things. */
+
+ // Try to figure out who sent this packet.
- n = lookup_node_udp(&from);
+ node_t *n = lookup_node_udp(&addr);
if(!n) {
- n = try_harder(&from, &pkt);
- if(n)
- update_node_udp(n, &from);
- else if(debug_level >= DEBUG_PROTOCOL) {
- hostname = sockaddr2hostname(&from);
+ // It might be from a 1.1 node, which might have a source ID in the packet.
+ 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(sptps_verify_datagram(&from->sptps, DATA(&pkt), pkt.len - 2 * sizeof(node_id_t)))
+ n = from;
+ else
+ goto skip_harder;
+ }
+ }
+
+ if(!n) {
+ pkt.offset = 0;
+ n = try_harder(&addr, &pkt);
+ }
+
+skip_harder:
+ if(!n) {
+ if(debug_level >= DEBUG_PROTOCOL) {
+ hostname = sockaddr2hostname(&addr);
logger(DEBUG_PROTOCOL, LOG_WARNING, "Received UDP packet from unknown source %s", hostname);
free(hostname);
+ }
+ return;
+ }
+
+ if(n->status.sptps) {
+ pkt.offset = 2 * sizeof(node_id_t);
+
+ if(!memcmp(DSTID(&pkt), &nullid, sizeof nullid)) {
+ direct = true;
+ from = n;
+ to = myself;
+ } else {
+ from = lookup_node_id(SRCID(&pkt));
+ to = lookup_node_id(DSTID(&pkt));
+ }
+ if(!from || !to) {
+ logger(DEBUG_PROTOCOL, LOG_WARNING, "Received UDP packet from %s (%s) with unknown source and/or destination ID", n->name, n->hostname);
return;
}
- else
+
+ if(to != myself) {
+ send_sptps_data_priv(to, n, 0, DATA(&pkt), pkt.len - 2 * sizeof(node_id_t));
return;
+ }
+ } else {
+ direct = true;
+ from = n;
}
- n->sock = ls - listen_socket;
+ pkt.offset = 0;
+ if(!receive_udppacket(from, &pkt))
+ return;
- receive_udppacket(n, &pkt);
+ n->sock = ls - listen_socket;
+ if(direct && sockaddrcmp(&addr, &n->address))
+ update_node_udp(n, &addr);
}
void handle_device_data(void *data, int flags) {
vpn_packet_t packet;
-
+ packet.offset = DEFAULT_PACKET_OFFSET;
packet.priority = 0;
if(devops.read(&packet)) {
projects / tinc / blobdiff