Enable retransmit timer for SYN packets.

[utcp] / utcp.c

diff --git a/utcp.c b/utcp.c
index 8143e0e8eae20906e974d51e4635f34abd2fda87..a8ea8272972650a773b45009f83e23ec02da4d05 100644 (file)
--- a/utcp.c
+++ b/utcp.c
@@ -127,6 +127,10 @@ static bool fin_wanted(struct utcp_connection *c, uint32_t seq) {
        }
 }
 
+static bool is_reliable(struct utcp_connection *c) {
+       return c->flags & UTCP_RELIABLE;
+}
+
 static inline void list_connections(struct utcp *utcp) {
        debug("%p has %d connections:\n", utcp, utcp->nconnections);
        for(int i = 0; i < utcp->nconnections; i++)
@@ -389,24 +393,33 @@ struct utcp_connection *utcp_connect_ex(struct utcp *utcp, uint16_t dst, utcp_re
        c->recv = recv;
        c->priv = priv;
 
-       struct hdr hdr;
-
-       hdr.src = c->src;
-       hdr.dst = c->dst;
-       hdr.seq = c->snd.iss;
-       hdr.ack = 0;
-       hdr.wnd = c->rcv.wnd;
-       hdr.ctl = SYN;
-       hdr.aux = 0;
+       struct {
+               struct hdr hdr;
+               uint8_t init[4];
+       } pkt;
+
+       pkt.hdr.src = c->src;
+       pkt.hdr.dst = c->dst;
+       pkt.hdr.seq = c->snd.iss;
+       pkt.hdr.ack = 0;
+       pkt.hdr.wnd = c->rcv.wnd;
+       pkt.hdr.ctl = SYN;
+       pkt.hdr.aux = 0x0101;
+       pkt.init[0] = 1;
+       pkt.init[1] = 0;
+       pkt.init[2] = 0;
+       pkt.init[3] = flags & 0x7;
 
        set_state(c, SYN_SENT);
 
-       print_packet(utcp, "send", &hdr, sizeof hdr);
-       utcp->send(utcp, &hdr, sizeof hdr);
+       print_packet(utcp, "send", &pkt, sizeof pkt);
+       utcp->send(utcp, &pkt, sizeof pkt);
 
        gettimeofday(&c->conn_timeout, NULL);
        c->conn_timeout.tv_sec += utcp->timeout;
 
+       start_retransmit_timer(c);
+
        return c;
 }
 
@@ -514,7 +527,7 @@ ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) {
                return -1;
        }
 
-       // Add data to send buffer
+       // Exit early if we have nothing to send.
 
        if(!len)
                return 0;
@@ -524,6 +537,8 @@ ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) {
                return -1;
        }
 
+       // Add data to send buffer.
+
        len = buffer_put(&c->sndbuf, data, len);
        if(len <= 0) {
                errno = EWOULDBLOCK;
@@ -532,7 +547,11 @@ ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) {
 
        c->snd.last += len;
        ack(c, false);
-       if(!timerisset(&c->rtrx_timeout))
+       if(!is_reliable(c)) {
+               c->snd.una = c->snd.nxt = c->snd.last;
+               buffer_get(&c->sndbuf, NULL, c->sndbuf.used);
+       }
+       if(is_reliable(c) && !timerisset(&c->rtrx_timeout))
                start_retransmit_timer(c);
        return len;
 }
@@ -568,12 +587,18 @@ static void retransmit(struct utcp_connection *c) {
 
        switch(c->state) {
                case SYN_SENT:
+                       fprintf(stderr, "Retransmitting SYN\n");
                        // Send our SYN again
                        pkt->hdr.seq = c->snd.iss;
                        pkt->hdr.ack = 0;
                        pkt->hdr.ctl = SYN;
-                       print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr);
-                       utcp->send(utcp, pkt, sizeof pkt->hdr);
+                       pkt->hdr.aux = 0x0101;
+                       pkt->data[0] = 1;
+                       pkt->data[1] = 0;
+                       pkt->data[2] = 0;
+                       pkt->data[3] = c->flags & 0x7;
+                       print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr + 4);
+                       utcp->send(utcp, pkt, sizeof pkt->hdr + 4);
                        break;
 
                case SYN_RECEIVED:
@@ -750,6 +775,12 @@ static void handle_in_order(struct utcp_connection *c, const void *data, size_t
 
 
 static void handle_incoming_data(struct utcp_connection *c, uint32_t seq, const void *data, size_t len) {
+       if(!is_reliable(c)) {
+               c->recv(c, data, len);
+               c->rcv.nxt = seq + len;
+               return;
+       }
+
        uint32_t offset = seqdiff(seq, c->rcv.nxt);
        if(offset + len > c->rcvbuf.maxsize)
                abort();
@@ -826,6 +857,19 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
                                goto reset;
                        }
 
+                       // Parse auxilliary information
+                       if(hdr.aux) {
+                               if(hdr.aux != 0x0101 || len < 4 || ((uint8_t *)data)[0] != 1) {
+                                       len = 1;
+                                       goto reset;
+                               }
+                               c->flags = ((uint8_t *)data)[3] & 0x7;
+                               data += 4;
+                               len -= 4;
+                       } else {
+                               c->flags = UTCP_TCP;
+                       }
+
                        // Return SYN+ACK, go to SYN_RECEIVED state
                        c->snd.wnd = hdr.wnd;
                        c->rcv.irs = hdr.seq;
@@ -1052,7 +1096,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
                        break;
                }
        } else {
-               if(!len) {
+               if(!len && is_reliable(c)) {
                        c->dupack++;
                        if(c->dupack == 3) {
                                debug("Triplicate ACK\n");
@@ -1072,7 +1116,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
                timerclear(&c->conn_timeout); // It will be set anew in utcp_timeout() if c->snd.una != c->snd.nxt.
                if(c->snd.una == c->snd.last)
                        stop_retransmit_timer(c);
-               else
+               else if(is_reliable(c))
                        start_retransmit_timer(c);
        }
 
@@ -1391,8 +1435,15 @@ struct timeval utcp_timeout(struct utcp *utcp) {
                        retransmit(c);
                }
 
-               if(c->poll && buffer_free(&c->sndbuf) && (c->state == ESTABLISHED || c->state == CLOSE_WAIT))
-                       c->poll(c, buffer_free(&c->sndbuf));
+               if(c->poll) {
+                       if((c->state == ESTABLISHED || c->state == CLOSE_WAIT)) {
+                               uint32_t len =  buffer_free(&c->sndbuf);
+                               if(len)
+                                       c->poll(c, len);
+                       } else if(c->state == CLOSED) {
+                               c->poll(c, 0);
+                       }
+               }
 
                if(timerisset(&c->conn_timeout) && timercmp(&c->conn_timeout, &next, <))
                        next = c->conn_timeout;