Ensure FIN packets start the retransmission timer as well.

[utcp] / utcp.c

diff --git a/utcp.c b/utcp.c
index 5427c3e3798ef2fa470c1f89942bde3bdb480912..89a38b7d1c9546e94458531031b2ea419dad9cd6 100644 (file)
--- a/utcp.c
+++ b/utcp.c
@@ -86,11 +86,24 @@ static void print_packet(struct utcp *utcp, const char *dir, const void *pkt, si
                debug("ACK");
 
        if(len > sizeof hdr) {
-               debug(" data=");
-               for(int i = sizeof hdr; i < len; i++) {
-                       const char *data = pkt;
-                       debug("%c", data[i] >= 32 ? data[i] : '.');
+               uint32_t datalen = len - sizeof hdr;
+               uint8_t *str = malloc((datalen << 1) + 7);
+               memcpy(str, " data=", 6);
+               uint8_t *strptr = str + 6;
+               const uint8_t *data = pkt;
+               const uint8_t *dataend = data + datalen;
+
+               while(data != dataend) {
+                       *strptr = (*data >> 4) > 9? (*data >> 4) + 55 : (*data >> 4) + 48;
+                       ++strptr;
+                       *strptr = (*data & 0xf) > 9? (*data & 0xf) + 55 : (*data & 0xf) + 48;
+                       ++strptr;
+                       ++data;
                }
+               *strptr = 0;
+
+               debug(str);
+               free(str);
        }
 
        debug("\n");
@@ -260,6 +273,7 @@ static void free_connection(struct utcp_connection *c) {
        memmove(cp, cp + 1, (utcp->nconnections - i - 1) * sizeof *cp);
        utcp->nconnections--;
 
+       buffer_exit(&c->rcvbuf);
        buffer_exit(&c->sndbuf);
        free(c);
 }
@@ -305,6 +319,7 @@ static struct utcp_connection *allocate_connection(struct utcp *utcp, uint16_t s
        }
 
        if(!buffer_init(&c->rcvbuf, DEFAULT_RCVBUFSIZE, DEFAULT_MAXRCVBUFSIZE)) {
+               buffer_exit(&c->sndbuf);
                free(c);
                return NULL;
        }
@@ -548,13 +563,14 @@ static void retransmit(struct utcp_connection *c) {
 
        pkt->hdr.src = c->src;
        pkt->hdr.dst = c->dst;
+       pkt->hdr.wnd = c->rcv.wnd;
+       pkt->hdr.aux = 0;
 
        switch(c->state) {
                case SYN_SENT:
                        // Send our SYN again
                        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);
@@ -850,18 +866,22 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 
        if(c->state == SYN_SENT)
                acceptable = true;
-
-       // TODO: handle packets overlapping c->rcv.nxt.
-#if 1
-       // Only use this when accepting out-of-order packets.
        else if(len == 0)
                acceptable = seqdiff(hdr.seq, c->rcv.nxt) >= 0;
-       else
+       else {
+               int32_t rcv_offset = seqdiff(hdr.seq, c->rcv.nxt);
+
+               // cut already accepted front overlapping
+               if(rcv_offset < 0) {
+                       acceptable = rcv_offset + len >= 0;
+                       if(acceptable) {
+                               data -= rcv_offset;
+                               len += rcv_offset;
+                       }
+               }
+
                acceptable = seqdiff(hdr.seq, c->rcv.nxt) >= 0 && seqdiff(hdr.seq, c->rcv.nxt) + len <= c->rcvbuf.maxsize;
-#else
-       if(c->state != SYN_SENT)
-               acceptable = hdr.seq == c->rcv.nxt;
-#endif
+       }
 
        if(!acceptable) {
                debug("Packet not acceptable, %u <= %u + %zu < %u\n", c->rcv.nxt, hdr.seq, len, c->rcv.nxt + c->rcvbuf.maxsize);
@@ -1017,6 +1037,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
                                //Reset the congestion window so we wait for ACKs.
                                c->snd.nxt = c->snd.una;
                                c->snd.cwnd = utcp->mtu;
+                               start_retransmit_timer(c);
                        }
                }
        }
@@ -1164,7 +1185,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
        // - or we got an ack, so we should maybe send a bit more data
        //   -> sendatleastone = false
 
-       ack(c, prevrcvnxt != c->rcv.nxt);
+       ack(c, len || prevrcvnxt != c->rcv.nxt);
        return 0;
 
 reset:
@@ -1241,6 +1262,8 @@ int utcp_shutdown(struct utcp_connection *c, int dir) {
        c->snd.last++;
 
        ack(c, false);
+       if(!timerisset(&c->rtrx_timeout))
+               start_retransmit_timer(c);
        return 0;
 }
 
@@ -1321,6 +1344,7 @@ struct timeval utcp_timeout(struct utcp *utcp) {
                if(!c)
                        continue;
 
+               // delete connections that have been utcp_close()d.
                if(c->state == CLOSED) {
                        if(c->reapable) {
                                debug("Reaping %p\n", c);
@@ -1339,6 +1363,7 @@ struct timeval utcp_timeout(struct utcp *utcp) {
                }
 
                if(timerisset(&c->rtrx_timeout) && timercmp(&c->rtrx_timeout, &now, <)) {
+                       debug("retransmit()\n");
                        retransmit(c);
                }
 
@@ -1395,6 +1420,7 @@ void utcp_exit(struct utcp *utcp) {
        for(int i = 0; i < utcp->nconnections; i++) {
                if(!utcp->connections[i]->reapable)
                        debug("Warning, freeing unclosed connection %p\n", utcp->connections[i]);
+               buffer_exit(&utcp->connections[i]->rcvbuf);
                buffer_exit(&utcp->connections[i]->sndbuf);
                free(utcp->connections[i]);
        }