Fix cornercases closing channels.

[meshlink] / src / utcp.c

diff --git a/src/utcp.c b/src/utcp.c
index c1add21808cd51031c07b5919b5aa90c4b1f84c7..20dd0aba049757ca30833779ec772c63ba685310 100644 (file)
--- a/src/utcp.c
+++ b/src/utcp.c
@@ -1368,7 +1368,7 @@ synack:
 
        if(c->state == CLOSED) {
                debug(c, "got packet for closed connection\n");
-               return 0;
+               goto reset;
        }
 
        // It is for an existing connection.
@@ -1456,17 +1456,6 @@ synack:
                }
        }
 
-       if(hdr.ctl & ACK && (seqdiff(hdr.ack, c->snd.last) > 0 || seqdiff(hdr.ack, c->snd.una) < 0)) {
-               debug(c, "packet ack seqno out of range, %u <= %u < %u\n", c->snd.una, hdr.ack, c->snd.una + c->sndbuf.used);
-
-               // Ignore unacceptable RST packets.
-               if(hdr.ctl & RST) {
-                       return 0;
-               }
-
-               goto reset;
-       }
-
        // 2. Handle RST packets
 
        if(hdr.ctl & RST) {
@@ -1556,14 +1545,14 @@ synack:
 
        // 3. Advance snd.una
 
+       if(seqdiff(hdr.ack, c->snd.last) > 0 || seqdiff(hdr.ack, c->snd.una) < 0) {
+               debug(c, "packet ack seqno out of range, %u <= %u < %u\n", c->snd.una, hdr.ack, c->snd.una + c->sndbuf.used);
+               goto reset;
+       }
+
        advanced = seqdiff(hdr.ack, c->snd.una);
 
        if(advanced) {
-               if(c->reapable && !is_reliable(c)) {
-                       // TODO: we should also send RST for reliable connections
-                       goto reset;
-               }
-
                // RTT measurement
                if(c->rtt_start.tv_sec) {
                        if(c->rtt_seq == hdr.ack) {
@@ -1783,8 +1772,15 @@ skip_ack:
                        return 0;
 
                case ESTABLISHED:
+                       break;
+
                case FIN_WAIT_1:
                case FIN_WAIT_2:
+                       if(c->reapable) {
+                               // We already closed the connection and are not interested in more data.
+                               goto reset;
+                       }
+
                        break;
 
                case CLOSE_WAIT:
@@ -2006,7 +2002,7 @@ static bool reset_connection(struct utcp_connection *c) {
        hdr.src = c->src;
        hdr.dst = c->dst;
        hdr.seq = c->snd.nxt;
-       hdr.ack = 0;
+       hdr.ack = c->rcv.nxt;
        hdr.wnd = 0;
        hdr.ctl = RST;
 
@@ -2049,10 +2045,6 @@ void utcp_abort_all_connections(struct utcp *utcp) {
 }
 
 int utcp_close(struct utcp_connection *c) {
-       if(c->rcvbuf.used) {
-               return reset_connection(c) ? 0 : -1;
-       }
-
        if(utcp_shutdown(c, SHUT_RDWR) && errno != ENOTCONN) {
                return -1;
        }