X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=utcp.c;h=b0ba05428926ba1dd11c7b91c942d27d1fae97e7;hb=7271cf87721ab667a03f50bd40b4a8ec83b989d3;hp=fceffbd0856b2a383b008bafb7f488f1ae3489fa;hpb=de87ec33f4c97689d670ea58c48bb0a74d235042;p=utcp

diff --git a/utcp.c b/utcp.c
index fceffbd..b0ba054 100644
--- a/utcp.c
+++ b/utcp.c
@@ -49,13 +49,13 @@
 	(r)->tv_sec = (a)->tv_sec - (b)->tv_sec;\
 	(r)->tv_usec = (a)->tv_usec - (b)->tv_usec;\
 	if((r)->tv_usec < 0)\
-		(r)->tv_sec--, (r)->tv_usec += 1000000;\
+		(r)->tv_sec--, (r)->tv_usec += USEC_PER_SEC;\
 } while (0)
 #endif
 
-#ifndef max
-#define max(a, b) ((a) > (b) ? (a) : (b))
-#endif
+static inline size_t max(size_t a, size_t b) {
+	return a > b ? a : b;
+}
 
 #ifdef UTCP_DEBUG
 #include <stdarg.h>
@@ -70,12 +70,12 @@ static void debug(const char *format, ...) {
 static void print_packet(struct utcp *utcp, const char *dir, const void *pkt, size_t len) {
 	struct hdr hdr;
 	if(len < sizeof hdr) {
-		debug("%p %s: short packet (%zu bytes)\n", utcp, dir, len);
+		debug("%p %s: short packet (%lu bytes)\n", utcp, dir, (unsigned long)len);
 		return;
 	}
 
 	memcpy(&hdr, pkt, sizeof hdr);
-	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);
+	debug("%p %s: len=%lu, src=%u dst=%u seq=%u ack=%u wnd=%u ctl=", utcp, dir, (unsigned long)len, hdr.src, hdr.dst, hdr.seq, hdr.ack, hdr.wnd);
 	if(hdr.ctl & SYN)
 		debug("SYN");
 	if(hdr.ctl & RST)
@@ -86,11 +86,18 @@ static void print_packet(struct utcp *utcp, const char *dir, const void *pkt, si
 		debug("ACK");
 
 	if(len > sizeof hdr) {
-		debug(" data=");
-		for(int i = sizeof hdr; i < len; i++) {
-			const char *data = pkt;
-			debug("%c", data[i] >= 32 ? data[i] : '.');
+		uint32_t datalen = len - sizeof hdr;
+		const uint8_t *data = (uint8_t *)pkt + sizeof hdr;
+		char str[datalen * 2 + 1];
+		char *p = str;
+
+		for(uint32_t i = 0; i < datalen; i++) {
+			*p++ = "0123456789ABCDEF"[data[i] >> 4];
+			*p++ = "0123456789ABCDEF"[data[i] & 15];
 		}
+		*p = 0;
+
+		debug(" data=%s", str);
 	}
 
 	debug("\n");
@@ -138,13 +145,12 @@ static ssize_t buffer_put_at(struct buffer *buf, size_t offset, const void *data
 	if(buf->maxsize <= buf->used)
 		return 0;
 
-	debug("buffer_put_at %zu %zu %zu\n", buf->used, offset, len);
+	debug("buffer_put_at %lu %lu %lu\n", (unsigned long)buf->used, (unsigned long)offset, (unsigned long)len);
 
 	size_t required = offset + len;
 	if(required > buf->maxsize) {
 		if(offset >= buf->maxsize)
 			return 0;
-		abort();
 		len = buf->maxsize - offset;
 		required = buf->maxsize;
 	}
@@ -156,7 +162,7 @@ static ssize_t buffer_put_at(struct buffer *buf, size_t offset, const void *data
 		} else {
 			do {
 				newsize *= 2;
-			} while(newsize < buf->used + len);
+			} while(newsize < required);
 		}
 		if(newsize > buf->maxsize)
 			newsize = buf->maxsize;
@@ -260,6 +266,7 @@ static void free_connection(struct utcp_connection *c) {
 	memmove(cp, cp + 1, (utcp->nconnections - i - 1) * sizeof *cp);
 	utcp->nconnections--;
 
+	buffer_exit(&c->rcvbuf);
 	buffer_exit(&c->sndbuf);
 	free(c);
 }
@@ -305,6 +312,7 @@ static struct utcp_connection *allocate_connection(struct utcp *utcp, uint16_t s
 	}
 
 	if(!buffer_init(&c->rcvbuf, DEFAULT_RCVBUFSIZE, DEFAULT_MAXRCVBUFSIZE)) {
+		buffer_exit(&c->sndbuf);
 		free(c);
 		return NULL;
 	}
@@ -532,8 +540,11 @@ static void swap_ports(struct hdr *hdr) {
 }
 
 static void retransmit(struct utcp_connection *c) {
-	if(c->state == CLOSED || c->snd.nxt == c->snd.una)
+	if(c->state == CLOSED || c->snd.last == c->snd.una) {
+		debug("Retransmit() called but nothing to retransmit!\n");
+		stop_retransmit_timer(c);
 		return;
+	}
 
 	struct utcp *utcp = c->utcp;
 
@@ -548,13 +559,14 @@ static void retransmit(struct utcp_connection *c) {
 
 	pkt->hdr.src = c->src;
 	pkt->hdr.dst = c->dst;
+	pkt->hdr.wnd = c->rcv.wnd;
+	pkt->hdr.aux = 0;
 
 	switch(c->state) {
 		case SYN_SENT:
 			// Send our SYN again
 			pkt->hdr.seq = c->snd.iss;
 			pkt->hdr.ack = 0;
-			pkt->hdr.wnd = c->rcv.wnd;
 			pkt->hdr.ctl = SYN;
 			print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr);
 			utcp->send(utcp, pkt, sizeof pkt->hdr);
@@ -614,11 +626,31 @@ cleanup:
 	free(pkt);
 }
 
-// Update receive buffer and SACK entries after consuming data.
+/* Update receive buffer and SACK entries after consuming data.
+ *
+ * Situation:
+ *
+ * |.....0000..1111111111.....22222......3333|
+ * |---------------^
+ *
+ * 0..3 represent the SACK entries. The ^ indicates up to which point we want
+ * to remove data from the receive buffer. The idea is to substract "len"
+ * from the offset of all the SACK entries, and then remove/cut down entries
+ * that are shifted to before the start of the receive buffer.
+ *
+ * There are three cases:
+ * - the SACK entry is after ^, in that case just change the offset.
+ * - the SACK entry starts before and ends after ^, so we have to
+ *   change both its offset and size.
+ * - the SACK entry is completely before ^, in that case delete it.
+ */
 static void sack_consume(struct utcp_connection *c, size_t len) {
-	debug("sack_consume %zu\n", len);
-	if(len > c->rcvbuf.used)
-		abort();
+	debug("sack_consume %lu\n", (unsigned long)len);
+	if(len > c->rcvbuf.used) {
+		debug("All SACK entries consumed");
+		c->sacks[0].len = 0;
+		return;
+	}
 
 	buffer_get(&c->rcvbuf, NULL, len);
 
@@ -627,13 +659,13 @@ static void sack_consume(struct utcp_connection *c, size_t len) {
 			c->sacks[i].offset -= len;
 			i++;
 		} else if(len < c->sacks[i].offset + c->sacks[i].len) {
-			c->sacks[i].offset = 0;
 			c->sacks[i].len -= len - c->sacks[i].offset;
+			c->sacks[i].offset = 0;
 			i++;
 		} else {
 			if(i < NSACKS - 1) {
 				memmove(&c->sacks[i], &c->sacks[i + 1], (NSACKS - 1 - i) * sizeof c->sacks[i]);
-				c->sacks[i + 1].len = 0;
+				c->sacks[NSACKS - 1].len = 0;
 			} else {
 				c->sacks[i].len = 0;
 				break;
@@ -666,6 +698,8 @@ static void handle_out_of_order(struct utcp_connection *c, uint32_t offset, cons
 					memmove(&c->sacks[i + 1], &c->sacks[i], (NSACKS - i - 1) * sizeof c->sacks[i]);
 					c->sacks[i].offset = offset;
 					c->sacks[i].len = rxd;
+				} else {
+					debug("SACK entries full, dropping packet\n");
 				}
 				break;
 			} else { // merge
@@ -690,7 +724,7 @@ static void handle_out_of_order(struct utcp_connection *c, uint32_t offset, cons
 static void handle_in_order(struct utcp_connection *c, const void *data, size_t len) {
 	// Check if we can process out-of-order data now.
 	if(c->sacks[0].len && len >= c->sacks[0].offset) { // TODO: handle overlap with second SACK
-		debug("incoming packet len %zu connected with SACK at %u\n", len, c->sacks[0].offset);
+		debug("incoming packet len %lu connected with SACK at %u\n", (unsigned long)len, c->sacks[0].offset);
 		buffer_put_at(&c->rcvbuf, 0, data, len); // TODO: handle return value
 		len = max(len, c->sacks[0].offset + c->sacks[0].len);
 		data = c->rcvbuf.data;
@@ -815,8 +849,10 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 	// In case this is for a CLOSED connection, ignore the packet.
 	// TODO: make it so incoming packets can never match a CLOSED connection.
 
-	if(c->state == CLOSED)
+	if(c->state == CLOSED) {
+		debug("Got packet for closed connection\n");
 		return 0;
+	}
 
 	// It is for an existing connection.
 
@@ -850,21 +886,25 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 
 	if(c->state == SYN_SENT)
 		acceptable = true;
-
-	// TODO: handle packets overlapping c->rcv.nxt.
-#if 1
-	// Only use this when accepting out-of-order packets.
 	else if(len == 0)
 		acceptable = seqdiff(hdr.seq, c->rcv.nxt) >= 0;
-	else
+	else {
+		int32_t rcv_offset = seqdiff(hdr.seq, c->rcv.nxt);
+
+		// cut already accepted front overlapping
+		if(rcv_offset < 0) {
+			acceptable = rcv_offset + len >= 0;
+			if(acceptable) {
+				data -= rcv_offset;
+				len += rcv_offset;
+			}
+		}
+
 		acceptable = seqdiff(hdr.seq, c->rcv.nxt) >= 0 && seqdiff(hdr.seq, c->rcv.nxt) + len <= c->rcvbuf.maxsize;
-#else
-	if(c->state != SYN_SENT)
-		acceptable = hdr.seq == c->rcv.nxt;
-#endif
+	}
 
 	if(!acceptable) {
-		debug("Packet not acceptable, %u <= %u + %zu < %u\n", c->rcv.nxt, hdr.seq, len, c->rcv.nxt + c->rcvbuf.maxsize);
+		debug("Packet not acceptable, %u <= %u + %lu < %u\n", c->rcv.nxt, hdr.seq, (unsigned long)len, c->rcv.nxt + c->rcvbuf.maxsize);
 		// Ignore unacceptable RST packets.
 		if(hdr.ctl & RST)
 			return 0;
@@ -879,10 +919,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 	// ackno should not roll back, and it should also not be bigger than what we ever could have sent
 	// (= snd.una + c->sndbuf.used).
 
-	if(hdr.ctl & ACK &&
-			((seqdiff(hdr.ack, c->snd.una + c->sndbuf.used) > 0 &&
-			  seqdiff(hdr.ack, c->snd.nxt) > 0) // TODO: simplify this if
-			 || seqdiff(hdr.ack, c->snd.una) < 0)) {
+	if(hdr.ctl & ACK && (seqdiff(hdr.ack, c->snd.last) > 0 || seqdiff(hdr.ack, c->snd.una) < 0)) {
 		debug("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)
@@ -1020,6 +1057,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 				//Reset the congestion window so we wait for ACKs.
 				c->snd.nxt = c->snd.una;
 				c->snd.cwnd = utcp->mtu;
+				start_retransmit_timer(c);
 			}
 		}
 	}
@@ -1167,8 +1205,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 	// - or we got an ack, so we should maybe send a bit more data
 	//   -> sendatleastone = false
 
-ack:
-	ack(c, prevrcvnxt != c->rcv.nxt);
+	ack(c, len || prevrcvnxt != c->rcv.nxt);
 	return 0;
 
 reset:
@@ -1245,11 +1282,13 @@ int utcp_shutdown(struct utcp_connection *c, int dir) {
 	c->snd.last++;
 
 	ack(c, false);
+	if(!timerisset(&c->rtrx_timeout))
+		start_retransmit_timer(c);
 	return 0;
 }
 
 int utcp_close(struct utcp_connection *c) {
-	if(utcp_shutdown(c, SHUT_RDWR))
+	if(utcp_shutdown(c, SHUT_RDWR) && errno != ENOTCONN)
 		return -1;
 	c->recv = NULL;
 	c->poll = NULL;
@@ -1325,6 +1364,7 @@ struct timeval utcp_timeout(struct utcp *utcp) {
 		if(!c)
 			continue;
 
+		// delete connections that have been utcp_close()d.
 		if(c->state == CLOSED) {
 			if(c->reapable) {
 				debug("Reaping %p\n", c);
@@ -1343,6 +1383,7 @@ struct timeval utcp_timeout(struct utcp *utcp) {
 		}
 
 		if(timerisset(&c->rtrx_timeout) && timercmp(&c->rtrx_timeout, &now, <)) {
+			debug("retransmit()\n");
 			retransmit(c);
 		}
 
@@ -1387,8 +1428,8 @@ struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_
 	utcp->send = send;
 	utcp->priv = priv;
 	utcp->mtu = DEFAULT_MTU;
-	utcp->timeout = DEFAULT_USER_TIMEOUT; // s
-	utcp->rto = START_RTO; // us
+	utcp->timeout = DEFAULT_USER_TIMEOUT; // sec
+	utcp->rto = START_RTO; // usec
 
 	return utcp;
 }
@@ -1399,6 +1440,7 @@ void utcp_exit(struct utcp *utcp) {
 	for(int i = 0; i < utcp->nconnections; i++) {
 		if(!utcp->connections[i]->reapable)
 			debug("Warning, freeing unclosed connection %p\n", utcp->connections[i]);
+		buffer_exit(&utcp->connections[i]->rcvbuf);
 		buffer_exit(&utcp->connections[i]->sndbuf);
 		free(utcp->connections[i]);
 	}