if(!utcp->srtt) {
utcp->srtt = rtt;
utcp->rttvar = rtt / 2;
- utcp->rto = rtt + max(2 * rtt, CLOCK_GRANULARITY);
} else {
utcp->rttvar = (utcp->rttvar * 3 + absdiff(utcp->srtt, rtt)) / 4;
utcp->srtt = (utcp->srtt * 7 + rtt) / 8;
- utcp->rto = utcp->srtt + max(utcp->rttvar, CLOCK_GRANULARITY);
}
+ utcp->rto = utcp->srtt + max(4 * utcp->rttvar, CLOCK_GRANULARITY);
+
if(utcp->rto > MAX_RTO) {
utcp->rto = MAX_RTO;
}
struct {
struct hdr hdr;
uint8_t data[];
- } *pkt;
-
- pkt = malloc(sizeof(pkt->hdr) + c->utcp->mtu);
-
- if(!pkt) {
- return;
- }
+ } *pkt = c->utcp->pkt;
pkt->hdr.src = c->src;
pkt->hdr.dst = c->dst;
print_packet(c->utcp, "send", pkt, sizeof(pkt->hdr) + seglen);
c->utcp->send(c->utcp, pkt, sizeof(pkt->hdr) + seglen);
} while(left);
-
- free(pkt);
}
ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) {
if(is_reliable(c) || (c->state != SYN_SENT && c->state != SYN_RECEIVED)) {
len = buffer_put(&c->sndbuf, data, len);
+ } else {
+ return 0;
}
if(len <= 0) {
struct {
struct hdr hdr;
uint8_t data[];
- } *pkt;
-
- pkt = malloc(sizeof(pkt->hdr) + c->utcp->mtu);
-
- if(!pkt) {
- return;
- }
+ } *pkt = c->utcp->pkt;
pkt->hdr.src = c->src;
pkt->hdr.dst = c->dst;
c->rtt_start.tv_sec = 0; // invalidate RTT timer
cleanup:
- free(pkt);
+ return;
}
/* Update receive buffer and SACK entries after consuming data.
c->flags = UTCP_TCP;
}
+synack:
// Return SYN+ACK, go to SYN_RECEIVED state
c->snd.wnd = hdr.wnd;
c->rcv.irs = hdr.seq;
assert(data_acked >= 0);
+#ifndef NDEBUG
int32_t bufused = seqdiff(c->snd.last, c->snd.una);
assert(data_acked <= bufused);
+#endif
if(data_acked) {
buffer_get(&c->sndbuf, NULL, data_acked);
case CLOSING:
if(c->snd.una == c->snd.last) {
gettimeofday(&c->conn_timeout, NULL);
- c->conn_timeout.tv_sec += 60;
+ c->conn_timeout.tv_sec += utcp->timeout;
set_state(c, TIME_WAIT);
}
break;
case SYN_RECEIVED:
+ // This is a retransmit of a SYN, send back the SYNACK.
+ goto synack;
+
case ESTABLISHED:
case FIN_WAIT_1:
case FIN_WAIT_2:
case FIN_WAIT_2:
gettimeofday(&c->conn_timeout, NULL);
- c->conn_timeout.tv_sec += 60;
+ c->conn_timeout.tv_sec += utcp->timeout;
set_state(c, TIME_WAIT);
break;
utcp->pre_accept = pre_accept;
utcp->send = send;
utcp->priv = priv;
- utcp->mtu = DEFAULT_MTU;
+ utcp_set_mtu(utcp, DEFAULT_MTU);
utcp->timeout = DEFAULT_USER_TIMEOUT; // sec
utcp->rto = START_RTO; // usec
}
void utcp_set_mtu(struct utcp *utcp, uint16_t mtu) {
- // TODO: handle overhead of the header
- if(utcp) {
- utcp->mtu = mtu;
+ if (!utcp) {
+ return;
}
+
+ if (mtu <= sizeof(struct hdr)) {
+ return;
+ }
+
+ if (mtu > utcp->mtu) {
+ char *new = realloc(utcp->pkt, mtu);
+ if (!new)
+ return;
+ utcp->pkt = new;
+ }
+
+ utcp->mtu = mtu;
}
void utcp_reset_timers(struct utcp *utcp) {