/*
net_packet.c -- Handles in- and outgoing VPN packets
Copyright (C) 1998-2005 Ivo Timmermans,
- 2000-2012 Guus Sliepen <guus@tinc-vpn.org>
+ 2000-2013 Guus Sliepen <guus@tinc-vpn.org>
2010 Timothy Redaelli <timothy@redaelli.eu>
2010 Brandon Black <blblack@gmail.com>
#include "system.h"
-#include <openssl/rand.h>
-#include <openssl/err.h>
-#include <openssl/evp.h>
-#include <openssl/pem.h>
-#include <openssl/hmac.h>
-
#ifdef HAVE_ZLIB
#include <zlib.h>
#endif
#include "net.h"
#include "netutl.h"
#include "protocol.h"
-#include "process.h"
#include "route.h"
#include "utils.h"
#include "xalloc.h"
unsigned replaywin = 16;
bool localdiscovery = false;
+sockaddr_t localdiscovery_address;
#define MAX_SEQNO 1073741824
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.
+ 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, a fourth packet is added to each batch,
+ 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) {
timeout = pingtimeout;
}
- for(int i = 0; i < 3 + localdiscovery; i++) {
+ for(int i = 0; i < 4 + localdiscovery; i++) {
int len;
- if(n->maxmtu <= n->minmtu)
+ 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);
randomize(packet.data + 14, len - 14);
packet.len = len;
- if(i >= 3 && n->mtuprobes <= 10)
- packet.priority = -1;
- else
- packet.priority = 0;
+ packet.priority = 0;
+ n->status.broadcast = 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.broadcast = 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});
}
}
static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
- logger(DEBUG_TRAFFIC, LOG_INFO, "Got MTU probe length %d from %s (%s)", packet->len, n->name, n->hostname);
-
if(!packet->data[0]) {
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Got MTU probe request %d from %s (%s)", packet->len, n->name, n->hostname);
+
/* It's a probe request, send back a reply */
- packet->data[0] = 1;
+ /* Type 2 probe replies were introduced in protocol 17.3 */
+ if ((n->options >> 24) == 3) {
+ uint8_t* data = packet->data;
+ *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;
+ } else {
+ /* Legacy protocol: n won't understand type 2 probe replies. */
+ packet->data[0] = 1;
+ }
/* Temporarily set udp_confirmed, so that the reply is sent
back exactly the way it came in. */
send_udppacket(n, packet);
n->status.udp_confirmed = udp_confirmed;
} else {
+ length_t probelen = len;
+ if (packet->data[0] == 2) {
+ if (len < 3)
+ logger(DEBUG_TRAFFIC, LOG_WARNING, "Received invalid (too short) MTU probe reply from %s (%s)", n->name, n->hostname);
+ else {
+ uint16_t probelen16; memcpy(&probelen16, packet->data + 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);
+
/* It's a valid reply: now we know bidirectional communication
is possible using the address and socket that the reply
packet used. */
/* 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(n->minmtu)
n->mtuprobes = 30;
else
/* If applicable, raise the minimum supported MTU */
- if(len > n->maxmtu)
- len = n->maxmtu;
- if(n->minmtu < len)
- n->minmtu = len;
+ if(probelen > n->maxmtu)
+ probelen = n->maxmtu;
+ if(n->minmtu < probelen)
+ n->minmtu = probelen;
+
+ /* Calculate RTT and bandwidth.
+ 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).
+ */
+
+ struct timeval now, diff;
+ gettimeofday(&now, NULL);
+ 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);
+ probe_timestamp.tv_sec = ntohl(sec);
+ probe_timestamp.tv_usec = ntohl(usec);
+ }
+
+ n->probe_counter++;
+
+ 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);
+ }
}
}
if(n->status.sptps)
return sptps_verify_datagram(&n->sptps, (char *)&inpkt->seqno, inpkt->len);
- if(!digest_active(&n->indigest) || inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest))
+ if(!digest_active(n->indigest) || inpkt->len < sizeof inpkt->seqno + digest_length(n->indigest))
return false;
- return digest_verify(&n->indigest, &inpkt->seqno, inpkt->len - n->indigest.maclength, (const char *)&inpkt->seqno + inpkt->len - n->indigest.maclength);
+ return digest_verify(n->indigest, &inpkt->seqno, inpkt->len - digest_length(n->indigest), (const char *)&inpkt->seqno + inpkt->len - digest_length(n->indigest));
}
static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
size_t outlen;
if(n->status.sptps) {
+ if(!n->sptps.state) {
+ if(!n->status.waitingforkey) {
+ logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but we haven't exchanged keys yet", n->name, n->hostname);
+ send_req_key(n);
+ } else {
+ logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet", n->name, n->hostname);
+ }
+ return;
+ }
sptps_receive_data(&n->sptps, (char *)&inpkt->seqno, inpkt->len);
return;
}
- if(!cipher_active(&n->incipher)) {
- logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet",
- n->name, n->hostname);
+ 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;
}
/* Check packet length */
- if(inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest)) {
+ if(inpkt->len < sizeof inpkt->seqno + digest_length(n->indigest)) {
logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got too short packet from %s (%s)",
n->name, n->hostname);
return;
/* Check the message authentication code */
- if(digest_active(&n->indigest)) {
- inpkt->len -= n->indigest.maclength;
- if(!digest_verify(&n->indigest, &inpkt->seqno, inpkt->len, (const char *)&inpkt->seqno + inpkt->len)) {
+ 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)) {
logger(DEBUG_TRAFFIC, LOG_DEBUG, "Got unauthenticated packet from %s (%s)", n->name, n->hostname);
return;
}
}
/* Decrypt the packet */
- if(cipher_active(&n->incipher)) {
+ if(cipher_active(n->incipher)) {
outpkt = pkt[nextpkt++];
outlen = MAXSIZE;
- if(!cipher_decrypt(&n->incipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
+ if(!cipher_decrypt(n->incipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
logger(DEBUG_TRAFFIC, LOG_DEBUG, "Error decrypting packet from %s (%s)", n->name, n->hostname);
return;
}
if(inpkt->seqno > n->received_seqno)
n->received_seqno = inpkt->seqno;
+ n->received++;
+
if(n->received_seqno > MAX_SEQNO)
regenerate_key();
void receive_tcppacket(connection_t *c, const char *buffer, int len) {
vpn_packet_t outpkt;
+ if(len > sizeof outpkt.data)
+ return;
+
outpkt.len = len;
if(c->options & OPTION_TCPONLY)
outpkt.priority = 0;
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 < time(NULL)) {
+ 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;
*sock = rand() % listen_sockets;
if(listen_socket[*sock].sa.sa.sa_family == AF_INET6) {
- broadcast_ipv6.in6.sin6_port = n->prevedge->address.in.sin_port;
- broadcast_ipv6.in6.sin6_scope_id = listen_socket[*sock].sa.in6.sin6_scope_id;
- *sa = &broadcast_ipv6;
+ if(localdiscovery_address.sa.sa_family == AF_INET6) {
+ localdiscovery_address.in6.sin6_port = n->prevedge->address.in.sin_port;
+ *sa = &localdiscovery_address;
+ } else {
+ broadcast_ipv6.in6.sin6_port = n->prevedge->address.in.sin_port;
+ broadcast_ipv6.in6.sin6_scope_id = listen_socket[*sock].sa.in6.sin6_scope_id;
+ *sa = &broadcast_ipv6;
+ }
} else {
- broadcast_ipv4.in.sin_port = n->prevedge->address.in.sin_port;
- *sa = &broadcast_ipv4;
+ if(localdiscovery_address.sa.sa_family == AF_INET) {
+ localdiscovery_address.in.sin_port = n->prevedge->address.in.sin_port;
+ *sa = &localdiscovery_address;
+ } else {
+ broadcast_ipv4.in.sin_port = n->prevedge->address.in.sin_port;
+ *sa = &broadcast_ipv4;
+ }
}
}
/* Encrypt the packet */
- if(cipher_active(&n->outcipher)) {
+ if(cipher_active(n->outcipher)) {
outpkt = pkt[nextpkt++];
outlen = MAXSIZE;
- if(!cipher_encrypt(&n->outcipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
+ if(!cipher_encrypt(n->outcipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &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)) {
- digest_create(&n->outdigest, &inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + inpkt->len);
- inpkt->len += digest_length(&n->outdigest);
+ if(digest_active(n->outdigest)) {
+ if(!digest_create(n->outdigest, &inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + inpkt->len)) {
+ logger(DEBUG_TRAFFIC, LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
+ goto end;
+ }
+
+ inpkt->len += digest_length(n->outdigest);
}
/* Send the packet */
const sockaddr_t *sa;
int sock;
- /* Overloaded use of priority field: -1 means local broadcast */
-
- if(origpriority == -1 && n->prevedge)
+ if(n->status.broadcast)
choose_broadcast_address(n, &sa, &sock);
else
choose_udp_address(n, &sa, &sock);
/* Send it via TCP if it is a handshake packet, TCPOnly is in use, or this packet is larger than the MTU. */
- if(type >= SPTPS_HANDSHAKE || ((myself->options | to->options) & OPTION_TCPONLY) || (type != PKT_PROBE && len > to->minmtu)) {
+ if(type >= SPTPS_HANDSHAKE || ((myself->options | to->options) & OPTION_TCPONLY) || (type != PKT_PROBE && (len - SPTPS_DATAGRAM_OVERHEAD) > to->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)
- return send_request(to->nexthop->connection, "%d %s %s %s -1 -1 -1 %d", ANS_KEY, myself->name, to->name, buf, myself->incompression);
- else
+ if(!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);
+ } else {
return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_SPTPS, buf);
+ }
}
/* Otherwise, send the packet via UDP */
const sockaddr_t *sa;
int sock;
- choose_udp_address(to, &sa, &sock);
+ if(to->status.broadcast)
+ choose_broadcast_address(to, &sa, &sock);
+ else
+ choose_udp_address(to, &sa, &sock);
if(sendto(listen_socket[sock].udp.fd, data, len, 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)
break;
for splay_each(node_t, n, node_tree)
- if(n->status.reachable && ((n->via == myself && n->nexthop == n) || n->via == n))
+ if(n->status.reachable && n != myself && ((n->via == myself && n->nexthop == n) || n->via == n))
send_packet(n, packet);
break;
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