Avoid calling time(NULL).

[tinc] / src / net_packet.c

diff --git a/src/net_packet.c b/src/net_packet.c
index c0be8c4..8a4cebd 100644 (file)
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -1,7 +1,7 @@
 /*
     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>
 
@@ -22,12 +22,6 @@
 
 #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
@@ -70,11 +64,15 @@ bool localdiscovery = false;
    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) {
@@ -125,13 +123,18 @@ 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;
@@ -140,7 +143,7 @@ static void send_mtu_probe_handler(void *data) {
                memset(packet.data, 0, 14);
                randomize(packet.data + 14, len - 14);
                packet.len = len;
-               if(i >= 3 && n->mtuprobes <= 10)
+               if(i >= 4 && n->mtuprobes <= 10)
                        packet.priority = -1;
                else
                        packet.priority = 0;
@@ -150,6 +153,21 @@ static void send_mtu_probe_handler(void *data) {
                send_udppacket(n, &packet);
        }
 
+       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});
 }
@@ -184,6 +202,13 @@ static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
                /* If we haven't established the PMTU yet, restart the discovery process. */
 
                if(n->mtuprobes > 30) {
+                       if (len == 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
@@ -196,6 +221,25 @@ static void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
                        len = n->maxmtu;
                if(n->minmtu < len)
                        n->minmtu = len;
+
+               /* 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.
+                */
+
+               struct timeval now, diff;
+               gettimeofday(&now, NULL);
+               timersub(&now, &n->probe_time, &diff);
+               n->probe_counter++;
+
+               if(n->probe_counter == 1) {
+                       n->rtt = diff.tv_sec + diff.tv_usec * 1e-6;
+                       n->probe_time = now;
+               } else if(n->probe_counter == 3) {
+                       n->bandwidth = 2.0 * len / (diff.tv_sec + 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);
+               }
        }
 }
 
@@ -414,7 +458,7 @@ static void send_sptps_packet(node_t *n, vpn_packet_t *origpkt) {
                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;