Fix bug in retransmit().

[utcp] / utcp.c

diff --git a/utcp.c b/utcp.c
index 25590a091560df177d7bbd4d75afed8ad01ba4e1..7c577018888b0fd99b7cac6f9d66e29b9a0fd91c 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;
        }
@@ -532,8 +547,11 @@ static void swap_ports(struct hdr *hdr) {
 }
 
 static void retransmit(struct utcp_connection *c) {
-       if(c->state == CLOSED || c->snd.nxt == c->snd.una)
+       if(c->state == CLOSED || c->snd.last == c->snd.una) {
+               debug("Retransmit() called but nothing to retransmit!\n");
+               stop_retransmit_timer(c);
                return;
+       }
 
        struct utcp *utcp = c->utcp;
 
@@ -548,13 +566,14 @@ 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 +869,22 @@ 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);
@@ -1242,6 +1265,8 @@ 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;
 }
 
@@ -1398,6 +1423,7 @@ 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]);
        }