X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=utcp.c;h=340b059a6917e2738242b4292439a407924cc003;hb=9fc7e661dbe9f10f39d4d59644cf22be606031fd;hp=c21d6ab664b0146030c44d60e6feb730e924f0d8;hpb=7034cc75e0324210e96b3da5ac09c979b73173b7;p=utcp

diff --git a/utcp.c b/utcp.c
index c21d6ab..340b059 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 aux=%x ctl=", utcp, dir, (unsigned long)len, hdr.src, hdr.dst, hdr.seq, hdr.ack, hdr.wnd, hdr.aux);
 	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");
@@ -120,6 +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++)
@@ -135,16 +146,12 @@ static int32_t seqdiff(uint32_t a, uint32_t b) {
 
 // Store data into the buffer
 static ssize_t buffer_put_at(struct buffer *buf, size_t offset, const void *data, size_t len) {
-	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 +163,7 @@ 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 +267,7 @@ 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 +313,7 @@ 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;
 	}
@@ -373,35 +382,51 @@ static void stop_retransmit_timer(struct utcp_connection *c) {
 	debug("timeout cleared\n");
 }
 
-struct utcp_connection *utcp_connect(struct utcp *utcp, uint16_t dst, utcp_recv_t recv, void *priv) {
+struct utcp_connection *utcp_connect_ex(struct utcp *utcp, uint16_t dst, utcp_recv_t recv, void *priv, uint32_t flags) {
 	struct utcp_connection *c = allocate_connection(utcp, 0, dst);
 	if(!c)
 		return NULL;
 
+	assert((flags & ~0xf) == 0);
+
+	c->flags = flags;
 	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;
 }
 
+struct utcp_connection *utcp_connect(struct utcp *utcp, uint16_t dst, utcp_recv_t recv, void *priv) {
+	return utcp_connect_ex(utcp, dst, recv, priv, UTCP_TCP);
+}
+
 void utcp_accept(struct utcp_connection *c, utcp_recv_t recv, void *priv) {
 	if(c->reapable || c->state != SYN_RECEIVED) {
 		debug("Error: accept() called on invalid connection %p in state %s\n", c, strstate[c->state]);
@@ -432,7 +457,7 @@ static void ack(struct utcp_connection *c, bool sendatleastone) {
 
 	struct {
 		struct hdr hdr;
-		char data[];
+		uint8_t data[];
 	} *pkt;
 
 	pkt = malloc(sizeof pkt->hdr + c->utcp->mtu);
@@ -502,7 +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;
@@ -512,6 +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;
@@ -520,7 +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;
 }
@@ -532,14 +563,17 @@ 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;
 
 	struct {
 		struct hdr hdr;
-		char data[];
+		uint8_t data[];
 	} *pkt;
 
 	pkt = malloc(sizeof pkt->hdr + c->utcp->mtu);
@@ -548,16 +582,22 @@ 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);
+			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:
@@ -614,11 +654,31 @@ 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 +687,13 @@ 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 +726,8 @@ 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 +752,7 @@ 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;
@@ -712,6 +774,12 @@ 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();
@@ -760,6 +828,49 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 		return -1;
 	}
 
+	// Check for auxiliary headers
+
+	const uint8_t *init = NULL;
+
+	uint16_t aux = hdr.aux;
+	while(aux) {
+		size_t auxlen = 4 * (aux >> 8) & 0xf;
+		uint8_t auxtype = aux & 0xff;
+
+		if(len < auxlen) {
+			errno = EBADMSG;
+			return -1;
+		}
+
+		switch(auxtype) {
+		case AUX_INIT:
+			if(!(hdr.ctl & SYN) || auxlen != 4) {
+				errno = EBADMSG;
+				return -1;
+			}
+			init = data;
+			break;
+		default:
+			errno = EBADMSG;
+			return -1;
+		}
+
+		len -= auxlen;
+		data += auxlen;
+
+		if(!(aux & 0x800))
+			break;
+
+		if(len < 2) {
+			errno = EBADMSG;
+			return -1;
+		}
+
+		memcpy(&aux, data, 2);
+		len -= 2;
+		data += 2;
+	}
+
 	// Try to match the packet to an existing connection
 
 	struct utcp_connection *c = find_connection(utcp, hdr.dst, hdr.src);
@@ -788,19 +899,47 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 				goto reset;
 			}
 
+			// Parse auxilliary information
+			if(init) {
+				if(init[0] < 1) {
+					len = 1;
+					goto reset;
+				}
+				c->flags = init[3] & 0x7;
+			} else {
+				c->flags = UTCP_TCP;
+			}
+
 			// Return SYN+ACK, go to SYN_RECEIVED state
 			c->snd.wnd = hdr.wnd;
 			c->rcv.irs = hdr.seq;
 			c->rcv.nxt = c->rcv.irs + 1;
 			set_state(c, SYN_RECEIVED);
 
-			hdr.dst = c->dst;
-			hdr.src = c->src;
-			hdr.ack = c->rcv.irs + 1;
-			hdr.seq = c->snd.iss;
-			hdr.ctl = SYN | ACK;
-			print_packet(c->utcp, "send", &hdr, sizeof hdr);
-			utcp->send(utcp, &hdr, sizeof hdr);
+			struct {
+				struct hdr hdr;
+				uint8_t data[4];
+			} pkt;
+
+			pkt.hdr.src = c->src;
+			pkt.hdr.dst = c->dst;
+			pkt.hdr.ack = c->rcv.irs + 1;
+			pkt.hdr.seq = c->snd.iss;
+			pkt.hdr.wnd = c->rcv.wnd;
+			pkt.hdr.ctl = SYN | ACK;
+			if(init) {
+				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, "send", &pkt, sizeof hdr + 4);
+				utcp->send(utcp, &pkt, sizeof hdr + 4);
+			} else {
+				pkt.hdr.aux = 0;
+				print_packet(c->utcp, "send", &pkt, sizeof hdr);
+				utcp->send(utcp, &pkt, sizeof hdr);
+			}
 		} else {
 			// No, we don't want your packets, send a RST back
 			len = 1;
@@ -815,8 +954,10 @@ 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.
 
@@ -850,27 +991,31 @@ 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
-		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
+	else {
+		int32_t rcv_offset = seqdiff(hdr.seq, c->rcv.nxt);
+
+		// cut already accepted front overlapping
+		if(rcv_offset < 0) {
+			acceptable = len > -rcv_offset;
+			if(acceptable) {
+				data -= rcv_offset;
+				len += rcv_offset;
+				hdr.seq -= rcv_offset;
+			}
+		} else {
+			acceptable = seqdiff(hdr.seq, c->rcv.nxt) >= 0 && seqdiff(hdr.seq, c->rcv.nxt) + len <= c->rcvbuf.maxsize;
+		}
+	}
 
 	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;
-		// Otherwise, send an ACK back in the hope things improve.
-		ack(c, true);
-		return 0;
+		// Otherwise, continue processing.
+		len = 0;
 	}
 
 	c->snd.wnd = hdr.wnd; // TODO: move below
@@ -940,6 +1085,9 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 		}
 	}
 
+	if(!(hdr.ctl & ACK))
+		goto skip_ack;
+
 	// 3. Advance snd.una
 
 	uint32_t advanced = seqdiff(hdr.ack, c->snd.una);
@@ -1008,7 +1156,7 @@ 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");
@@ -1017,6 +1165,7 @@ 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);
 			}
 		}
 	}
@@ -1027,10 +1176,11 @@ 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);
 	}
 
+skip_ack:
 	// 5. Process SYN stuff
 
 	if(hdr.ctl & SYN) {
@@ -1053,7 +1203,7 @@ ssize_t utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 		case LAST_ACK:
 		case TIME_WAIT:
 			// Ehm, no. We should never receive a second SYN.
-			goto reset;
+			return 0;
 		default:
 #ifdef UTCP_DEBUG
 			abort();
@@ -1164,12 +1314,13 @@ 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(c, prevrcvnxt != c->rcv.nxt);
+	ack(c, len || prevrcvnxt != c->rcv.nxt);
 	return 0;
 
 reset:
 	swap_ports(&hdr);
 	hdr.wnd = 0;
+	hdr.aux = 0;
 	if(hdr.ctl & ACK) {
 		hdr.seq = hdr.ack;
 		hdr.ctl = RST;
@@ -1241,11 +1392,13 @@ 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;
@@ -1344,8 +1497,15 @@ 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;
@@ -1385,8 +1545,8 @@ 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;
 }
@@ -1397,6 +1557,7 @@ 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]);
 	}
@@ -1414,6 +1575,22 @@ void utcp_set_mtu(struct utcp *utcp, uint16_t mtu) {
 		utcp->mtu = mtu;
 }
 
+void utcp_reset_timers(struct utcp *utcp) {
+	if(!utcp)
+		return;
+	struct timeval now, then;
+	gettimeofday(&now, NULL);
+	then = now;
+	then.tv_sec += utcp->timeout;
+	for(int i = 0; i < utcp->nconnections; i++) {
+		utcp->connections[i]->rtrx_timeout = now;
+		utcp->connections[i]->conn_timeout = then;
+		utcp->connections[i]->rtt_start.tv_sec = 0;
+	}
+	if(utcp->rto > START_RTO)
+		utcp->rto = START_RTO;
+}
+
 int utcp_get_user_timeout(struct utcp *u) {
 	return u ? u->timeout : 0;
 }