X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=utcp.c;h=9f668edd37256e214db12347722c48a79dd8f4cf;hb=f4c52312544ee99bcce46ebcfc0c8e6ac6356fd5;hp=454a497428dd0e698db2bdeae92189fda41eb0fb;hpb=f60a19752749bf1d28031e78c46f8924325ffcdd;p=utcp

diff --git a/utcp.c b/utcp.c
index 454a497..9f668ed 100644
--- a/utcp.c
+++ b/utcp.c
@@ -19,6 +19,7 @@
 
 #define _GNU_SOURCE
 
+#include <assert.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -49,7 +50,7 @@ static void print_packet(struct utcp *utcp, const char *dir, const void *pkt, si
 	}
 
 	memcpy(&hdr, pkt, sizeof hdr);
-	fprintf (stderr, "%p %s: src=%u dst=%u seq=%u ack=%u wnd=%u ctl=", utcp, dir, hdr.src, hdr.dst, hdr.seq, hdr.ack, hdr.wnd);
+	fprintf (stderr, "%p %s: len=%zu, src=%u dst=%u seq=%u ack=%u wnd=%u ctl=", utcp, dir, len, hdr.src, hdr.dst, hdr.seq, hdr.ack, hdr.wnd);
 	if(hdr.ctl & SYN)
 		debug("SYN");
 	if(hdr.ctl & RST)
@@ -97,8 +98,9 @@ static int32_t seqdiff(uint32_t a, uint32_t b) {
 static int compare(const void *va, const void *vb) {
 	const struct utcp_connection *a = *(struct utcp_connection **)va;
 	const struct utcp_connection *b = *(struct utcp_connection **)vb;
-	if(!a->src || !b->src)
-		abort();
+
+	assert(a->src && b->src);
+
 	int c = (int)a->src - (int)b->src;
 	if(c)
 		return c;
@@ -120,13 +122,14 @@ static struct utcp_connection *find_connection(const struct utcp *utcp, uint16_t
 static void free_connection(struct utcp_connection *c) {
 	struct utcp *utcp = c->utcp;
 	struct utcp_connection **cp = bsearch(&c, utcp->connections, utcp->nconnections, sizeof *utcp->connections, compare);
-	if(!cp)
-		abort();
+
+	assert(cp);
 
 	int i = cp - utcp->connections;
 	memmove(cp + i, cp + i + 1, (utcp->nconnections - i - 1) * sizeof *cp);
 	utcp->nconnections--;
 
+	free(c->sndbuf);
 	free(c);
 }
 
@@ -206,8 +209,9 @@ struct utcp_connection *utcp_connect(struct utcp *utcp, uint16_t dst, utcp_recv_
 	hdr.dst = c->dst;
 	hdr.seq = c->snd.iss;
 	hdr.ack = 0;
-	hdr.ctl = SYN;
 	hdr.wnd = c->rcv.wnd;
+	hdr.ctl = SYN;
+	hdr.aux = 0;
 
 	set_state(c, SYN_SENT);
 
@@ -233,10 +237,12 @@ void utcp_accept(struct utcp_connection *c, utcp_recv_t recv, void *priv) {
 }
 
 static void ack(struct utcp_connection *c, bool sendatleastone) {
-	uint32_t left = seqdiff(c->snd.last, c->snd.nxt);
+	int32_t left = seqdiff(c->snd.last, c->snd.nxt);
 	int32_t cwndleft = c->snd.cwnd - seqdiff(c->snd.nxt, c->snd.una);
 	char *data = c->sndbuf + seqdiff(c->snd.nxt, c->snd.una);
 
+	assert(left >= 0);
+
 	if(cwndleft <= 0)
 		cwndleft = 0;
 
@@ -256,6 +262,7 @@ static void ack(struct utcp_connection *c, bool sendatleastone) {
 	pkt.hdr.ack = c->rcv.nxt;
 	pkt.hdr.wnd = c->snd.wnd;
 	pkt.hdr.ctl = ACK;
+	pkt.hdr.aux = 0;
 
 	do {
 		uint32_t seglen = left > c->utcp->mtu ? c->utcp->mtu : left;
@@ -267,6 +274,18 @@ static void ack(struct utcp_connection *c, bool sendatleastone) {
 		data += seglen;
 		left -= seglen;
 
+		if(c->state != ESTABLISHED && !left && seglen) {
+			switch(c->state) {
+			case FIN_WAIT_1:
+			case CLOSING:
+				seglen--;
+				pkt.hdr.ctl |= FIN;
+				break;
+			default:
+				break;
+			}
+		}
+
 		print_packet(c->utcp, "send", &pkt, sizeof pkt.hdr + seglen);
 		c->utcp->send(c->utcp, &pkt, sizeof pkt.hdr + seglen);
 	} while(left);
@@ -324,6 +343,12 @@ ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) {
 			newbufsize = c->maxsndbufsize;
 		else
 			newbufsize = c->sndbufsize * 2;
+		if(bufused + len > newbufsize) {
+			if(bufused + len > c->maxsndbufsize)
+				newbufsize = c->maxsndbufsize;
+			else
+				newbufsize = bufused + len;
+		}
 		char *newbuf = realloc(c->sndbuf, newbufsize);
 		if(newbuf) {
 			c->sndbuf = newbuf;
@@ -352,7 +377,7 @@ static void swap_ports(struct hdr *hdr) {
 	hdr->dst = tmp;
 }
 
-int utcp_recv(struct utcp *utcp, const void *data, size_t len) {
+ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 	if(!utcp) {
 		errno = EFAULT;
 		return -1;
@@ -584,12 +609,31 @@ int utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 		c->snd.cwnd += utcp->mtu;
 		if(c->snd.cwnd > c->maxsndbufsize)
 			c->snd.cwnd = c->maxsndbufsize;
+		debug("%p increasing cwnd to %u\n", utcp, c->snd.cwnd);
+
+		// Check if we have sent a FIN that is now ACKed.
+		switch(c->state) {
+		case FIN_WAIT_1:
+			if(c->snd.una == c->snd.last)
+				set_state(c, FIN_WAIT_2);
+			break;
+		case CLOSING:
+			if(c->snd.una == c->snd.last) {
+				gettimeofday(&c->conn_timeout, NULL);
+				c->conn_timeout.tv_sec += 60;
+				set_state(c, TIME_WAIT);
+			}
+			break;
+		default:
+			break;
+		}
 	} else {
 		if(!len) {
 			c->dupack++;
 			if(c->dupack >= 3) {
 				debug("Triplicate ACK\n");
-				abort();
+				//TODO: Resend one packet and go to fast recovery mode. See RFC 6582.
+				//abort();
 			}
 		}
 	}
@@ -597,7 +641,7 @@ int utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 	// 4. Update timers
 
 	if(advanced) {
-		timerclear(&c->conn_timeout); // It should be set anew in utcp_timeout() if c->snd.una != c->snd.nxt.
+		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.nxt)
 			timerclear(&c->rtrx_timeout);
 	}
@@ -671,10 +715,15 @@ int utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 			abort();
 		}
 
-		int rxd;
+		ssize_t rxd;
 
 		if(c->recv) {
 			rxd = c->recv(c, data, len);
+			if(rxd != len) {
+				// TODO: once we have a receive buffer, handle the application not accepting all data.
+				fprintf(stderr, "c->recv(%p, %p, %zu) returned %zd\n", c, data, len, rxd);
+				abort();
+			}
 			if(rxd < 0)
 				rxd = 0;
 			else if(rxd > len)
@@ -701,6 +750,8 @@ int utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 			set_state(c, CLOSING);
 			break;
 		case FIN_WAIT_2:
+			gettimeofday(&c->conn_timeout, NULL);
+			c->conn_timeout.tv_sec += 60;
 			set_state(c, TIME_WAIT);
 			break;
 		case CLOSE_WAIT:
@@ -715,6 +766,7 @@ int utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 
 		// FIN counts as one sequence number
 		c->rcv.nxt++;
+		len++;
 
 		// Inform the application that the peer closed the connection.
 		if(c->recv) {
@@ -751,7 +803,7 @@ reset:
 }
 
 int utcp_shutdown(struct utcp_connection *c, int dir) {
-	debug("%p shutdown %d\n", c->utcp, dir);
+	debug("%p shutdown %d\n", c ? c->utcp : NULL, dir);
 	if(!c) {
 		errno = EFAULT;
 		return -1;
@@ -790,21 +842,9 @@ int utcp_shutdown(struct utcp_connection *c, int dir) {
 		return 0;
 	}
 
-	// Send FIN
-
-	struct hdr hdr;
+	c->snd.last++;
 
-	hdr.src = c->src;
-	hdr.dst = c->dst;
-	hdr.seq = c->snd.nxt;
-	hdr.ack = c->rcv.nxt;
-	hdr.wnd = c->snd.wnd;
-	hdr.ctl = FIN | ACK;
-
-	c->snd.nxt += 1;
-
-	print_packet(c->utcp, "send", &hdr, sizeof hdr);
-	c->utcp->send(c->utcp, &hdr, sizeof hdr);
+	ack(c, false);
 	return 0;
 }
 
@@ -1007,8 +1047,13 @@ struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_
 void utcp_exit(struct utcp *utcp) {
 	if(!utcp)
 		return;
-	for(int i = 0; i < utcp->nconnections; i++)
-		free_connection(utcp->connections[i]);
+	for(int i = 0; i < utcp->nconnections; i++) {
+		if(!utcp->connections[i]->reapable)
+			debug("Warning, freeing unclosed connection %p\n", utcp->connections[i]);
+		free(utcp->connections[i]->sndbuf);
+		free(utcp->connections[i]);
+	}
+	free(utcp->connections);
 	free(utcp);
 }