Add UDP semantics.

[utcp] / utcp.c

diff --git a/utcp.c b/utcp.c
index 8143e0e8eae20906e974d51e4635f34abd2fda87..c650ab700ad150fa876b0944a6872ea39298f352 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++)
@@ -389,20 +393,27 @@ 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;
@@ -514,7 +525,7 @@ 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 +535,8 @@ 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 +545,11 @@ 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;
 }
@@ -750,6 +767,12 @@ 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 +849,19 @@ 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 +1088,7 @@ 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 +1108,7 @@ 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);
        }