From: Guus Sliepen <guus@tinc-vpn.org>
Date: Sun, 11 Jan 2015 13:44:15 +0000 (+0100)
Subject: Remove RTT and packet loss estimation code.
X-Git-Tag: release-1.1pre12~214
X-Git-Url: https://git.tinc-vpn.org/git/browse?a=commitdiff_plain;h=088b5fd9ee6d5f566e8726eae861cbc7cd832b17;p=tinc

Remove RTT and packet loss estimation code.

This is not working at all anymore. Just remove it, and we'll do another
attempt at RTT, bandwidth and packet loss estimation after the new
probing code stabilizes.
---

diff --git a/src/net_packet.c b/src/net_packet.c
index 76b3c5e9..f666fd98 100644
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -117,10 +117,6 @@ static void udp_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 			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 = MIN_PROBE_SIZE;
 		} else {
 			/* Legacy protocol: n won't understand type 2 probe replies. */
@@ -171,31 +167,6 @@ static void udp_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
 			n->minmtu = probelen;
 			try_fix_mtu(n);
 		}
-
-		/* Calculate RTT.
-		   The RTT is the time between the MTU probe burst was sent and the first
-		   reply is received.
-		 */
-
-		struct timeval now, diff;
-		gettimeofday(&now, NULL);
-		timersub(&now, &n->probe_time, &diff);
-
-		struct timeval probe_timestamp = now;
-		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);
-		}
-		
-		n->probe_counter++;
-
-		if(n->probe_counter == 1) {
-			n->rtt = diff.tv_sec + diff.tv_usec * 1e-6;
-			n->probe_time = probe_timestamp;
-			logger(DEBUG_TRAFFIC, LOG_DEBUG, "%s (%s) RTT %.2f ms, rx packet loss %.2f %%", n->name, n->hostname, n->rtt * 1e3, n->packetloss * 1e2);
-		}
 	}
 }
 
@@ -1000,7 +971,7 @@ static void try_mtu(node_t *n) {
 	   mtuprobes ==    -1: send one >maxmtu probe every pingtimeout */
 
 	struct timeval elapsed;
-	timersub(&now, &n->probe_sent_time, &elapsed);
+	timersub(&now, &n->mtu_ping_sent, &elapsed);
 	if(n->mtuprobes >= 0) {
 		if(n->mtuprobes != 0 && elapsed.tv_sec == 0 && elapsed.tv_usec < 333333)
 			return;
@@ -1009,6 +980,8 @@ static void try_mtu(node_t *n) {
 			return;
 	}
 
+	n->mtu_ping_sent = now;
+
 	try_fix_mtu(n);
 
 	if(n->mtuprobes < 0) {
@@ -1061,23 +1034,6 @@ static void try_mtu(node_t *n) {
 		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;
 }
 
 /* These functions try to establish a tunnel to a node (or its relay) so that
diff --git a/src/node.h b/src/node.h
index cd9e2d97..aadb0b5f 100644
--- a/src/node.h
+++ b/src/node.h
@@ -88,18 +88,15 @@ typedef struct node_t {
 	uint32_t farfuture;                     /* Packets in a row that have arrived from the far future */
 	unsigned char* late;                    /* Bitfield marking late packets */
 
-	struct timeval udp_ping_sent;           /* Last time a ping probe was sent */
+	struct timeval udp_ping_sent;           /* Last time a UDP probe was sent */
 	timeout_t udp_ping_timeout;             /* Ping timeout event */
 
+	struct timeval mtu_ping_sent;           /* Last time a MTU probe was sent */
+
 	length_t mtu;                           /* Maximum size of packets to send to this node */
 	length_t minmtu;                        /* Probed minimum MTU */
 	length_t maxmtu;                        /* Probed maximum MTU */
 	int mtuprobes;                          /* Number of probes */
-	struct timeval probe_sent_time;         /* Time the last probe was sent */
-	struct timeval probe_time;              /* Time the last probe was sent or received */
-	int probe_counter;                      /* Number of probes received since last burst was sent */
-	float rtt;                              /* Last measured round trip time */
-	float packetloss;                       /* Last measured packet loss rate */
 
 	uint64_t in_packets;
 	uint64_t in_bytes;