Make RTT variables per-connection.

We do congestion management per connection, so we should also track RTT per
connection.

diff --git a/utcp.c b/utcp.c
index 10d026efabf2679db6ca419c71131e5fecd7e582..9fa37b9f18671941da9b582e5157974df1dbe091 100644 (file)
--- a/utcp.c
+++ b/utcp.c
@@ -524,6 +524,9 @@ static struct utcp_connection *allocate_connection(struct utcp *utcp, uint16_t s
        c->snd.cwnd = (utcp->mss > 2190 ? 2 : utcp->mss > 1095 ? 3 : 4) * utcp->mss;
        c->snd.ssthresh = ~0;
        debug_cwnd(c);
+       c->srtt = 0;
+       c->rttvar = 0;
+       c->rto = START_RTO;
        c->utcp = utcp;
 
        // Add it to the sorted list of connections
@@ -549,36 +552,34 @@ static void update_rtt(struct utcp_connection *c, uint32_t rtt) {
                return;
        }
 
-       struct utcp *utcp = c->utcp;
-
-       if(!utcp->srtt) {
-               utcp->srtt = rtt;
-               utcp->rttvar = rtt / 2;
+       if(!c->srtt) {
+               c->srtt = rtt;
+               c->rttvar = rtt / 2;
        } else {
-               utcp->rttvar = (utcp->rttvar * 3 + absdiff(utcp->srtt, rtt)) / 4;
-               utcp->srtt = (utcp->srtt * 7 + rtt) / 8;
+               c->rttvar = (c->rttvar * 3 + absdiff(c->srtt, rtt)) / 4;
+               c->srtt = (c->srtt * 7 + rtt) / 8;
        }
 
-       utcp->rto = utcp->srtt + max(4 * utcp->rttvar, CLOCK_GRANULARITY);
+       c->rto = c->srtt + max(4 * c->rttvar, CLOCK_GRANULARITY);
 
-       if(utcp->rto > MAX_RTO) {
-               utcp->rto = MAX_RTO;
+       if(c->rto > MAX_RTO) {
+               c->rto = MAX_RTO;
        }
 
-       debug(c, "rtt %u srtt %u rttvar %u rto %u\n", rtt, utcp->srtt, utcp->rttvar, utcp->rto);
+       debug(c, "rtt %u srtt %u rttvar %u rto %u\n", rtt, c->srtt, c->rttvar, c->rto);
 }
 
 static void start_retransmit_timer(struct utcp_connection *c) {
        clock_gettime(UTCP_CLOCK, &c->rtrx_timeout);
 
-       uint32_t rto = c->utcp->rto;
+       uint32_t rto = c->rto;
 
        while(rto > USEC_PER_SEC) {
                c->rtrx_timeout.tv_sec++;
                rto -= USEC_PER_SEC;
        }
 
-       c->rtrx_timeout.tv_nsec += c->utcp->rto * 1000;
+       c->rtrx_timeout.tv_nsec += c->rto * 1000;
 
        if(c->rtrx_timeout.tv_nsec >= NSEC_PER_SEC) {
                c->rtrx_timeout.tv_nsec -= NSEC_PER_SEC;
@@ -973,10 +974,10 @@ static void retransmit(struct utcp_connection *c) {
        }
 
        start_retransmit_timer(c);
-       utcp->rto *= 2;
+       c->rto *= 2;
 
-       if(utcp->rto > MAX_RTO) {
-               utcp->rto = MAX_RTO;
+       if(c->rto > MAX_RTO) {
+               c->rto = MAX_RTO;
        }
 
        c->rtt_start.tv_sec = 0; // invalidate RTT timer
@@ -2173,7 +2174,6 @@ struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_
        utcp->priv = priv;
        utcp_set_mtu(utcp, DEFAULT_MTU);
        utcp->timeout = DEFAULT_USER_TIMEOUT; // sec
-       utcp->rto = START_RTO; // usec
 
        return utcp;
 }
@@ -2266,10 +2266,10 @@ void utcp_reset_timers(struct utcp *utcp) {
                }
 
                c->rtt_start.tv_sec = 0;
-       }
 
-       if(utcp->rto > START_RTO) {
-               utcp->rto = START_RTO;
+               if(c->rto > START_RTO) {
+                       c->rto = START_RTO;
+               }
        }
 }
 
@@ -2436,11 +2436,11 @@ void utcp_offline(struct utcp *utcp, bool offline) {
                        }
 
                        utcp->connections[i]->rtt_start.tv_sec = 0;
-               }
-       }
 
-       if(!offline && utcp->rto > START_RTO) {
-               utcp->rto = START_RTO;
+                       if(c->rto > START_RTO) {
+                               c->rto = START_RTO;
+                       }
+               }
        }
 }
 

diff --git a/utcp_priv.h b/utcp_priv.h
index 5672f06847bac45d3af4b0369730fe5ea8d3c032..58e2715a3c701cc392997b66c2bc85729f850336 100644 (file)
--- a/utcp_priv.h
+++ b/utcp_priv.h
@@ -146,6 +146,12 @@ struct utcp_connection {
        struct timespec rtt_start;
        uint32_t rtt_seq;
 
+       // RTT variables
+
+       uint32_t srtt; // usec
+       uint32_t rttvar; // usec
+       uint32_t rto; // usec
+
        // Buffers
 
        uint32_t prev_free;
@@ -184,12 +190,6 @@ struct utcp {
        uint16_t mss; // The maximum size of the payload of a UTCP packet.
        int timeout; // sec
 
-       // RTT variables
-
-       uint32_t srtt; // usec
-       uint32_t rttvar; // usec
-       uint32_t rto; // usec
-
        // Connection management
 
        struct utcp_connection **connections;