Fix check for return value of malloc().

[utcp] / utcp.c

diff --git a/utcp.c b/utcp.c
index d49c4ddcce2cfbf5822efb899b49b4cd186419c4..ce056904169c6923baa95a0e5435626e5da75fd5 100644 (file)
--- a/utcp.c
+++ b/utcp.c
@@ -103,6 +103,19 @@ static void set_state(struct utcp_connection *c, enum state state) {
        debug("%p new state: %s\n", c->utcp, strstate[state]);
 }
 
+static bool fin_wanted(struct utcp_connection *c, uint32_t seq) {
+       if(seq != c->snd.last)
+               return false;
+       switch(c->state) {
+       case FIN_WAIT_1:
+       case CLOSING:
+       case LAST_ACK:
+               return true;
+       default:
+               return false;
+       }
+}
+
 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++)
@@ -269,7 +282,12 @@ static struct utcp_connection *allocate_connection(struct utcp *utcp, uint16_t s
 
        c->src = src;
        c->dst = dst;
+#ifdef UTCP_DEBUG
+#warning debugging
+       c->snd.iss = 0;
+#else
        c->snd.iss = rand();
+#endif
        c->snd.una = c->snd.iss;
        c->snd.nxt = c->snd.iss + 1;
        c->rcv.wnd = utcp->mtu;
@@ -347,7 +365,7 @@ static void ack(struct utcp_connection *c, bool sendatleastone) {
        } *pkt;
 
        pkt = malloc(sizeof pkt->hdr + c->utcp->mtu);
-       if(!pkt->data)
+       if(!pkt)
                return;
 
        pkt->hdr.src = c->src;
@@ -366,16 +384,9 @@ static void ack(struct utcp_connection *c, bool sendatleastone) {
                c->snd.nxt += seglen;
                left -= seglen;
 
-               if(c->state != ESTABLISHED && seglen && c->snd.nxt == c->snd.last) {
-                       switch(c->state) {
-                       case FIN_WAIT_1:
-                       case CLOSING:
-                               seglen--;
-                               pkt->hdr.ctl |= FIN;
-                               break;
-                       default:
-                               break;
-                       }
+               if(seglen && fin_wanted(c, c->snd.nxt)) {
+                       seglen--;
+                       pkt->hdr.ctl |= FIN;
                }
 
                print_packet(c->utcp, "send", pkt, sizeof pkt->hdr + seglen);
@@ -459,11 +470,8 @@ static void retransmit(struct utcp_connection *c) {
        pkt->hdr.dst = c->dst;
 
        switch(c->state) {
-               case LISTEN:
-                       // TODO: this should not happen
-                       break;
-
                case SYN_SENT:
+                       // Send our SYN again
                        pkt->hdr.seq = c->snd.iss;
                        pkt->hdr.ack = 0;
                        pkt->hdr.wnd = c->rcv.wnd;
@@ -473,6 +481,7 @@ static void retransmit(struct utcp_connection *c) {
                        break;
 
                case SYN_RECEIVED:
+                       // Send SYNACK again
                        pkt->hdr.seq = c->snd.nxt;
                        pkt->hdr.ack = c->rcv.nxt;
                        pkt->hdr.ctl = SYN | ACK;
@@ -482,28 +491,35 @@ static void retransmit(struct utcp_connection *c) {
 
                case ESTABLISHED:
                case FIN_WAIT_1:
+               case CLOSE_WAIT:
+               case CLOSING:
+               case LAST_ACK:
+                       // Send unacked data again.
                        pkt->hdr.seq = c->snd.una;
                        pkt->hdr.ack = c->rcv.nxt;
                        pkt->hdr.ctl = ACK;
-                       uint32_t len = seqdiff(c->snd.nxt, c->snd.una);
-                       if(c->state == FIN_WAIT_1)
-                               len--;
+                       uint32_t len = seqdiff(c->snd.last, c->snd.una);
                        if(len > utcp->mtu)
                                len = utcp->mtu;
-                       else {
-                               if(c->state == FIN_WAIT_1)
-                                       pkt->hdr.ctl |= FIN;
+                       if(fin_wanted(c, c->snd.una + len)) {
+                               len--;
+                               pkt->hdr.ctl |= FIN;
                        }
+                       c->snd.nxt = c->snd.una + len;
                        buffer_copy(&c->sndbuf, pkt->data, 0, len);
                        print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr + len);
                        utcp->send(utcp, pkt, sizeof pkt->hdr + len);
                        break;
 
-               default:
-                       // TODO: implement
+               case CLOSED:
+               case LISTEN:
+               case TIME_WAIT:
+               case FIN_WAIT_2:
+                       // We shouldn't need to retransmit anything in this state.
 #ifdef UTCP_DEBUG
                        abort();
 #endif
+                       timerclear(&c->rtrx_timeout);
                        break;
        }
 
@@ -978,7 +994,7 @@ reset:
 }
 
 int utcp_shutdown(struct utcp_connection *c, int dir) {
-       debug("%p shutdown %d at %u\n", c ? c->utcp : NULL, dir, c->snd.last);
+       debug("%p shutdown %d at %u\n", c ? c->utcp : NULL, dir, c ? c->snd.last : 0);
        if(!c) {
                errno = EFAULT;
                return -1;
@@ -990,13 +1006,26 @@ int utcp_shutdown(struct utcp_connection *c, int dir) {
                return -1;
        }
 
-       // TODO: handle dir
-       // TODO: check that repeated calls with the same parameters should have no effect
+       if(!(dir == UTCP_SHUT_RD || dir == UTCP_SHUT_WR || dir == UTCP_SHUT_RDWR)) {
+               errno = EINVAL;
+               return -1;
+       }
+
+       // TCP does not have a provision for stopping incoming packets.
+       // The best we can do is to just ignore them.
+       if(dir == UTCP_SHUT_RD || dir == UTCP_SHUT_RDWR)
+               c->recv = NULL;
+
+       // The rest of the code deals with shutting down writes.
+       if(dir == UTCP_SHUT_RD)
+               return 0;
 
        switch(c->state) {
        case CLOSED:
-               return 0;
        case LISTEN:
+               errno = ENOTCONN;
+               return -1;
+
        case SYN_SENT:
                set_state(c, CLOSED);
                return 0;
@@ -1144,6 +1173,17 @@ struct timeval utcp_timeout(struct utcp *utcp) {
        return diff;
 }
 
+bool utcp_is_active(struct utcp *utcp) {
+       if(!utcp)
+               return false;
+
+       for(int i = 0; i < utcp->nconnections; i++)
+               if(utcp->connections[i]->state != CLOSED && utcp->connections[i]->state != TIME_WAIT)
+                       return true;
+
+       return false;
+}
+
 struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_send_t send, void *priv) {
        struct utcp *utcp = calloc(1, sizeof *utcp);
        if(!utcp)
@@ -1246,3 +1286,10 @@ void utcp_set_poll_cb(struct utcp_connection *c, utcp_poll_t poll) {
        if(c)
                c->poll = poll;
 }
+
+void utcp_set_accept_cb(struct utcp *utcp, utcp_accept_t accept, utcp_pre_accept_t pre_accept) {
+       if(utcp) {
+               utcp->accept = accept;
+               utcp->pre_accept = pre_accept;
+       }
+}