c->snd.nxt += seglen;
left -= seglen;
- if(c->state != ESTABLISHED && !left && seglen) {
+ if(c->state != ESTABLISHED && seglen && c->snd.nxt == c->snd.last) {
switch(c->state) {
case FIN_WAIT_1:
case CLOSING:
hdr->dst = tmp;
}
+static void retransmit(struct utcp_connection *c) {
+ if(c->state == CLOSED || c->snd.nxt == c->snd.una)
+ return;
+
+ struct utcp *utcp = c->utcp;
+
+ struct {
+ struct hdr hdr;
+ char data[];
+ } *pkt;
+
+ pkt = malloc(sizeof pkt->hdr + c->utcp->mtu);
+ if(!pkt)
+ return;
+
+ pkt->hdr.src = c->src;
+ pkt->hdr.dst = c->dst;
+
+ switch(c->state) {
+ case LISTEN:
+ // TODO: this should not happen
+ break;
+
+ case SYN_SENT:
+ pkt->hdr.seq = c->snd.iss;
+ pkt->hdr.ack = 0;
+ pkt->hdr.wnd = c->rcv.wnd;
+ pkt->hdr.ctl = SYN;
+ print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr);
+ utcp->send(utcp, pkt, sizeof pkt->hdr);
+ break;
+
+ case SYN_RECEIVED:
+ pkt->hdr.seq = c->snd.nxt;
+ pkt->hdr.ack = c->rcv.nxt;
+ pkt->hdr.ctl = SYN | ACK;
+ print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr);
+ utcp->send(utcp, pkt, sizeof pkt->hdr);
+ break;
+
+ case ESTABLISHED:
+ case FIN_WAIT_1:
+ pkt->hdr.seq = c->snd.una;
+ pkt->hdr.ack = c->rcv.nxt;
+ pkt->hdr.ctl = ACK;
+ uint32_t len = seqdiff(c->snd.nxt, c->snd.una);
+ if(c->state == FIN_WAIT_1)
+ len--;
+ if(len > utcp->mtu)
+ len = utcp->mtu;
+ else {
+ if(c->state == FIN_WAIT_1)
+ pkt->hdr.ctl |= FIN;
+ }
+ buffer_copy(&c->sndbuf, pkt->data, 0, len);
+ print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr + len);
+ utcp->send(utcp, pkt, sizeof pkt->hdr + len);
+ break;
+
+ default:
+ // TODO: implement
+#ifdef UTCP_DEBUG
+ abort();
+#endif
+ break;
+ }
+
+ free(pkt);
+}
+
+
ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
if(!utcp) {
errno = EFAULT;
case TIME_WAIT:
break;
default:
+#ifdef UTCP_DEBUG
abort();
+#endif
+ break;
}
// 1b. Drop packets with a sequence number not in our receive window.
set_state(c, CLOSED);
return 0;
default:
+#ifdef UTCP_DEBUG
abort();
+#endif
+ break;
}
}
} else {
if(!len) {
c->dupack++;
- if(c->dupack >= 3) {
+ if(c->dupack == 3) {
debug("Triplicate ACK\n");
//TODO: Resend one packet and go to fast recovery mode. See RFC 6582.
- //abort();
+ //We do a very simple variant here; reset the nxt pointer to the last acknowledged packet from the peer.
+ //This will cause us to start retransmitting, but at the same speed as the incoming ACKs arrive,
+ //thus preventing a drop in speed.
+ c->snd.nxt = c->snd.una;
}
}
}
// Ehm, no. We should never receive a second SYN.
goto reset;
default:
+#ifdef UTCP_DEBUG
abort();
+#endif
+ return 0;
}
// SYN counts as one sequence number
case SYN_SENT:
case SYN_RECEIVED:
// This should never happen.
+#ifdef UTCP_DEBUG
abort();
+#endif
+ return 0;
case ESTABLISHED:
case FIN_WAIT_1:
case FIN_WAIT_2:
// Ehm no, We should never receive more data after a FIN.
goto reset;
default:
+#ifdef UTCP_DEBUG
abort();
+#endif
+ return 0;
}
ssize_t rxd;
case SYN_SENT:
case SYN_RECEIVED:
// This should never happen.
+#ifdef UTCP_DEBUG
abort();
+#endif
+ break;
case ESTABLISHED:
set_state(c, CLOSE_WAIT);
break;
// Ehm, no. We should never receive a second FIN.
goto reset;
default:
+#ifdef UTCP_DEBUG
abort();
+#endif
+ break;
}
// FIN counts as one sequence number
}
int utcp_shutdown(struct utcp_connection *c, int dir) {
- debug("%p shutdown %d\n", c ? c->utcp : NULL, dir);
+ debug("%p shutdown %d at %u\n", c ? c->utcp : NULL, dir, c->snd.last);
if(!c) {
errno = EFAULT;
return -1;
}
// TODO: handle dir
+ // TODO: check that repeated calls with the same parameters should have no effect
switch(c->state) {
case CLOSED:
return 0;
}
-static void retransmit(struct utcp_connection *c) {
- if(c->state == CLOSED || c->snd.nxt == c->snd.una)
- return;
-
- struct utcp *utcp = c->utcp;
-
- struct {
- struct hdr hdr;
- char data[];
- } *pkt;
-
- pkt = malloc(sizeof pkt->hdr + c->utcp->mtu);
- if(!pkt)
- return;
-
- pkt->hdr.src = c->src;
- pkt->hdr.dst = c->dst;
-
- switch(c->state) {
- case LISTEN:
- // TODO: this should not happen
- break;
-
- case SYN_SENT:
- pkt->hdr.seq = c->snd.iss;
- pkt->hdr.ack = 0;
- pkt->hdr.wnd = c->rcv.wnd;
- pkt->hdr.ctl = SYN;
- print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr);
- utcp->send(utcp, pkt, sizeof pkt->hdr);
- break;
-
- case SYN_RECEIVED:
- pkt->hdr.seq = c->snd.nxt;
- pkt->hdr.ack = c->rcv.nxt;
- pkt->hdr.ctl = SYN | ACK;
- print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr);
- utcp->send(utcp, pkt, sizeof pkt->hdr);
- break;
-
- case ESTABLISHED:
- case FIN_WAIT_1:
- pkt->hdr.seq = c->snd.una;
- pkt->hdr.ack = c->rcv.nxt;
- pkt->hdr.ctl = ACK;
- uint32_t len = seqdiff(c->snd.nxt, c->snd.una);
- if(c->state == FIN_WAIT_1)
- len--;
- if(len > utcp->mtu)
- len = utcp->mtu;
- else {
- if(c->state == FIN_WAIT_1)
- pkt->hdr.ctl |= FIN;
- }
- buffer_copy(&c->sndbuf, pkt->data, 0, len);
- print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr + len);
- utcp->send(utcp, pkt, sizeof pkt->hdr + len);
- break;
-
- default:
- // TODO: implement
- abort();
- }
-
- free(pkt);
-}
-
/* Handle timeouts.
* One call to this function will loop through all connections,
* checking if something needs to be resent or not.
}
uint16_t utcp_get_mtu(struct utcp *utcp) {
- return utcp->mtu;
+ return utcp ? utcp->mtu : 0;
}
void utcp_set_mtu(struct utcp *utcp, uint16_t mtu) {
// TODO: handle overhead of the header
- utcp->mtu = mtu;
+ if(utcp)
+ utcp->mtu = mtu;
}
int utcp_get_user_timeout(struct utcp *u) {
- return u->timeout;
+ return u ? u->timeout : 0;
}
void utcp_set_user_timeout(struct utcp *u, int timeout) {
- u->timeout = timeout;
+ if(u)
+ u->timeout = timeout;
}
size_t utcp_get_sndbuf(struct utcp_connection *c) {
- return c->sndbuf.maxsize;
+ return c ? c->sndbuf.maxsize : 0;
}
size_t utcp_get_sndbuf_free(struct utcp_connection *c) {
- return buffer_free(&c->sndbuf);
+ if(c && (c->state == ESTABLISHED || c->state == CLOSE_WAIT))
+ return buffer_free(&c->sndbuf);
+ else
+ return 0;
}
void utcp_set_sndbuf(struct utcp_connection *c, size_t size) {
+ if(!c)
+ return;
c->sndbuf.maxsize = size;
if(c->sndbuf.maxsize != size)
c->sndbuf.maxsize = -1;
}
bool utcp_get_nodelay(struct utcp_connection *c) {
- return c->nodelay;
+ return c ? c->nodelay : false;
}
void utcp_set_nodelay(struct utcp_connection *c, bool nodelay) {
- c->nodelay = nodelay;
+ if(c)
+ c->nodelay = nodelay;
}
bool utcp_get_keepalive(struct utcp_connection *c) {
- return c->keepalive;
+ return c ? c->keepalive : false;
}
void utcp_set_keepalive(struct utcp_connection *c, bool keepalive) {
- c->keepalive = keepalive;
+ if(c)
+ c->keepalive = keepalive;
}
size_t utcp_get_outq(struct utcp_connection *c) {
- return seqdiff(c->snd.nxt, c->snd.una);
+ return c ? seqdiff(c->snd.nxt, c->snd.una) : 0;
}
void utcp_set_recv_cb(struct utcp_connection *c, utcp_recv_t recv) {
- c->recv = recv;
+ if(c)
+ c->recv = recv;
}
void utcp_set_poll_cb(struct utcp_connection *c, utcp_poll_t poll) {
- c->poll = poll;
+ if(c)
+ c->poll = poll;
}
projects / utcp / blobdiff