X-Git-Url: http://git.meshlink.io/?p=utcp;a=blobdiff_plain;f=utcp.c;h=04d2b194c20f193aa44f2d4006b9afc1bd356b29;hp=10d026efabf2679db6ca419c71131e5fecd7e582;hb=HEAD;hpb=9470c449236afef22210803b359fe44d74e32636

diff --git a/utcp.c b/utcp.c
index 10d026e..04d2b19 100644
--- a/utcp.c
+++ b/utcp.c
@@ -74,6 +74,7 @@ static bool timespec_lt(const struct timespec *a, const struct timespec *b) {
 
 static void timespec_clear(struct timespec *a) {
 	a->tv_sec = 0;
+	a->tv_nsec = 0;
 }
 
 static bool timespec_isset(const struct timespec *a) {
@@ -267,7 +268,7 @@ static ssize_t buffer_put_at(struct buffer *buf, size_t offset, const void *data
 
 	uint32_t realoffset = buf->offset + offset;
 
-	if(buf->size - buf->offset < offset) {
+	if(buf->size - buf->offset <= offset) {
 		// The offset wrapped
 		realoffset -= buf->size;
 	}
@@ -304,7 +305,7 @@ static ssize_t buffer_copy(struct buffer *buf, void *data, size_t offset, size_t
 
 	uint32_t realoffset = buf->offset + offset;
 
-	if(buf->size - buf->offset < offset) {
+	if(buf->size - buf->offset <= offset) {
 		// The offset wrapped
 		realoffset -= buf->size;
 	}
@@ -321,7 +322,11 @@ static ssize_t buffer_copy(struct buffer *buf, void *data, size_t offset, size_t
 }
 
 // Copy data from the buffer without removing it.
-static ssize_t buffer_call(struct buffer *buf, utcp_recv_t cb, void *arg, size_t offset, size_t len) {
+static ssize_t buffer_call(struct utcp_connection *c, struct buffer *buf, size_t offset, size_t len) {
+	if(!c->recv) {
+		return len;
+	}
+
 	// Ensure we don't copy more than is actually stored in the buffer
 	if(offset >= buf->used) {
 		return 0;
@@ -333,20 +338,25 @@ static ssize_t buffer_call(struct buffer *buf, utcp_recv_t cb, void *arg, size_t
 
 	uint32_t realoffset = buf->offset + offset;
 
-	if(buf->size - buf->offset < offset) {
+	if(buf->size - buf->offset <= offset) {
 		// The offset wrapped
 		realoffset -= buf->size;
 	}
 
 	if(buf->size - realoffset < len) {
 		// The data is wrapped
-		ssize_t rx1 = cb(arg, buf->data + realoffset, buf->size - realoffset);
+		ssize_t rx1 = c->recv(c, buf->data + realoffset, buf->size - realoffset);
 
 		if(rx1 < buf->size - realoffset) {
 			return rx1;
 		}
 
-		ssize_t rx2 = cb(arg, buf->data, len - (buf->size - realoffset));
+		// The channel might have been closed by the previous callback
+		if(!c->recv) {
+			return len;
+		}
+
+		ssize_t rx2 = c->recv(c, buf->data, len - (buf->size - realoffset));
 
 		if(rx2 < 0) {
 			return rx2;
@@ -354,7 +364,7 @@ static ssize_t buffer_call(struct buffer *buf, utcp_recv_t cb, void *arg, size_t
 			return rx1 + rx2;
 		}
 	} else {
-		return cb(arg, buf->data + realoffset, len);
+		return c->recv(c, buf->data + realoffset, len);
 	}
 }
 
@@ -364,7 +374,7 @@ static ssize_t buffer_discard(struct buffer *buf, size_t len) {
 		len = buf->used;
 	}
 
-	if(buf->size - buf->offset < len) {
+	if(buf->size - buf->offset <= len) {
 		buf->offset -= buf->size;
 	}
 
@@ -400,7 +410,7 @@ static void buffer_exit(struct buffer *buf) {
 }
 
 static uint32_t buffer_free(const struct buffer *buf) {
-	return buf->maxsize - buf->used;
+	return buf->maxsize > buf->used ? buf->maxsize - buf->used : 0;
 }
 
 // Connections are stored in a sorted list.
@@ -524,6 +534,9 @@ static struct utcp_connection *allocate_connection(struct utcp *utcp, uint16_t s
 	c->snd.cwnd = (utcp->mss > 2190 ? 2 : utcp->mss > 1095 ? 3 : 4) * utcp->mss;
 	c->snd.ssthresh = ~0;
 	debug_cwnd(c);
+	c->srtt = 0;
+	c->rttvar = 0;
+	c->rto = START_RTO;
 	c->utcp = utcp;
 
 	// Add it to the sorted list of connections
@@ -549,36 +562,34 @@ static void update_rtt(struct utcp_connection *c, uint32_t rtt) {
 		return;
 	}
 
-	struct utcp *utcp = c->utcp;
-
-	if(!utcp->srtt) {
-		utcp->srtt = rtt;
-		utcp->rttvar = rtt / 2;
+	if(!c->srtt) {
+		c->srtt = rtt;
+		c->rttvar = rtt / 2;
 	} else {
-		utcp->rttvar = (utcp->rttvar * 3 + absdiff(utcp->srtt, rtt)) / 4;
-		utcp->srtt = (utcp->srtt * 7 + rtt) / 8;
+		c->rttvar = (c->rttvar * 3 + absdiff(c->srtt, rtt)) / 4;
+		c->srtt = (c->srtt * 7 + rtt) / 8;
 	}
 
-	utcp->rto = utcp->srtt + max(4 * utcp->rttvar, CLOCK_GRANULARITY);
+	c->rto = c->srtt + max(4 * c->rttvar, CLOCK_GRANULARITY);
 
-	if(utcp->rto > MAX_RTO) {
-		utcp->rto = MAX_RTO;
+	if(c->rto > MAX_RTO) {
+		c->rto = MAX_RTO;
 	}
 
-	debug(c, "rtt %u srtt %u rttvar %u rto %u\n", rtt, utcp->srtt, utcp->rttvar, utcp->rto);
+	debug(c, "rtt %u srtt %u rttvar %u rto %u\n", rtt, c->srtt, c->rttvar, c->rto);
 }
 
 static void start_retransmit_timer(struct utcp_connection *c) {
 	clock_gettime(UTCP_CLOCK, &c->rtrx_timeout);
 
-	uint32_t rto = c->utcp->rto;
+	uint32_t rto = c->rto;
 
 	while(rto > USEC_PER_SEC) {
 		c->rtrx_timeout.tv_sec++;
 		rto -= USEC_PER_SEC;
 	}
 
-	c->rtrx_timeout.tv_nsec += c->utcp->rto * 1000;
+	c->rtrx_timeout.tv_nsec += rto * 1000;
 
 	if(c->rtrx_timeout.tv_nsec >= NSEC_PER_SEC) {
 		c->rtrx_timeout.tv_nsec -= NSEC_PER_SEC;
@@ -814,7 +825,6 @@ ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) {
 	if(!is_reliable(c)) {
 		c->snd.una = c->snd.nxt = c->snd.last;
 		buffer_discard(&c->sndbuf, c->sndbuf.used);
-		c->do_poll = true;
 	}
 
 	if(is_reliable(c) && !timespec_isset(&c->rtrx_timeout)) {
@@ -846,13 +856,7 @@ static void fast_retransmit(struct utcp_connection *c) {
 	struct {
 		struct hdr hdr;
 		uint8_t data[];
-	} *pkt;
-
-	pkt = malloc(c->utcp->mtu);
-
-	if(!pkt) {
-		return;
-	}
+	} *pkt = c->utcp->pkt;
 
 	pkt->hdr.src = c->src;
 	pkt->hdr.dst = c->dst;
@@ -884,8 +888,6 @@ static void fast_retransmit(struct utcp_connection *c) {
 	default:
 		break;
 	}
-
-	free(pkt);
 }
 
 static void retransmit(struct utcp_connection *c) {
@@ -897,6 +899,10 @@ static void retransmit(struct utcp_connection *c) {
 
 	struct utcp *utcp = c->utcp;
 
+	if(utcp->retransmit) {
+		utcp->retransmit(c);
+	}
+
 	struct {
 		struct hdr hdr;
 		uint8_t data[];
@@ -973,10 +979,10 @@ static void retransmit(struct utcp_connection *c) {
 	}
 
 	start_retransmit_timer(c);
-	utcp->rto *= 2;
+	c->rto *= 2;
 
-	if(utcp->rto > MAX_RTO) {
-		utcp->rto = MAX_RTO;
+	if(c->rto > MAX_RTO) {
+		c->rto = MAX_RTO;
 	}
 
 	c->rtt_start.tv_sec = 0; // invalidate RTT timer
@@ -1044,8 +1050,14 @@ static void handle_out_of_order(struct utcp_connection *c, uint32_t offset, cons
 	// Packet loss or reordering occured. Store the data in the buffer.
 	ssize_t rxd = buffer_put_at(&c->rcvbuf, offset, data, len);
 
-	if(rxd < 0 || (size_t)rxd < len) {
-		abort();
+	if(rxd <= 0) {
+		debug(c, "packet outside receive buffer, dropping\n");
+		return;
+	}
+
+	if((size_t)rxd < len) {
+		debug(c, "packet partially outside receive buffer\n");
+		len = rxd;
 	}
 
 	// Make note of where we put it.
@@ -1106,7 +1118,8 @@ static void handle_in_order(struct utcp_connection *c, const void *data, size_t
 			size_t offset = len;
 			len = c->sacks[0].offset + c->sacks[0].len;
 			size_t remainder = len - offset;
-			ssize_t rxd = buffer_call(&c->rcvbuf, c->recv, c, offset, remainder);
+
+			ssize_t rxd = buffer_call(c, &c->rcvbuf, offset, remainder);
 
 			if(rxd != (ssize_t)remainder) {
 				// TODO: handle the application not accepting all data.
@@ -1125,7 +1138,10 @@ static void handle_in_order(struct utcp_connection *c, const void *data, size_t
 static void handle_unreliable(struct utcp_connection *c, const struct hdr *hdr, const void *data, size_t len) {
 	// Fast path for unfragmented packets
 	if(!hdr->wnd && !(hdr->ctl & MF)) {
-		c->recv(c, data, len);
+		if(c->recv) {
+			c->recv(c, data, len);
+		}
+
 		c->rcv.nxt = hdr->seq + len;
 		return;
 	}
@@ -1153,7 +1169,7 @@ static void handle_unreliable(struct utcp_connection *c, const struct hdr *hdr,
 
 	// Send the packet if it's the final fragment
 	if(!(hdr->ctl & MF)) {
-		buffer_call(&c->rcvbuf, c->recv, c, 0, hdr->wnd + len);
+		buffer_call(c, &c->rcvbuf, 0, hdr->wnd + len);
 	}
 
 	c->rcv.nxt = hdr->seq + len;
@@ -1167,10 +1183,6 @@ static void handle_incoming_data(struct utcp_connection *c, const struct hdr *hd
 
 	uint32_t offset = seqdiff(hdr->seq, c->rcv.nxt);
 
-	if(offset + len > c->rcvbuf.maxsize) {
-		abort();
-	}
-
 	if(offset) {
 		handle_out_of_order(c, offset, data, len);
 	} else {
@@ -1347,6 +1359,8 @@ synack:
 				print_packet(c, "send", &pkt, sizeof(hdr));
 				utcp->send(utcp, &pkt, sizeof(hdr));
 			}
+
+			start_retransmit_timer(c);
 		} else {
 			// No, we don't want your packets, send a RST back
 			len = 1;
@@ -1590,7 +1604,10 @@ synack:
 
 		if(data_acked) {
 			buffer_discard(&c->sndbuf, data_acked);
-			c->do_poll = true;
+
+			if(is_reliable(c)) {
+				c->do_poll = true;
+			}
 		}
 
 		// Also advance snd.nxt if possible
@@ -1705,7 +1722,7 @@ skip_ack:
 			}
 
 			c->rcv.irs = hdr.seq;
-			c->rcv.nxt = hdr.seq;
+			c->rcv.nxt = hdr.seq + 1;
 
 			if(c->shut_wr) {
 				c->snd.last++;
@@ -1714,7 +1731,6 @@ skip_ack:
 				set_state(c, ESTABLISHED);
 			}
 
-			// TODO: notify application of this somehow.
 			break;
 
 		case SYN_RECEIVED:
@@ -1728,8 +1744,8 @@ skip_ack:
 		case CLOSING:
 		case LAST_ACK:
 		case TIME_WAIT:
-			// Ehm, no. We should never receive a second SYN.
-			return 0;
+			// This could be a retransmission. Ignore the SYN flag, but send an ACK back.
+			break;
 
 		default:
 #ifdef UTCP_DEBUG
@@ -1737,9 +1753,6 @@ skip_ack:
 #endif
 			return 0;
 		}
-
-		// SYN counts as one sequence number
-		c->rcv.nxt++;
 	}
 
 	// 6. Process new data
@@ -2161,6 +2174,13 @@ struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_
 		return NULL;
 	}
 
+	utcp_set_mtu(utcp, DEFAULT_MTU);
+
+	if(!utcp->pkt) {
+		free(utcp);
+		return NULL;
+	}
+
 	if(!CLOCK_GRANULARITY) {
 		struct timespec res;
 		clock_getres(UTCP_CLOCK, &res);
@@ -2171,9 +2191,7 @@ struct utcp *utcp_init(utcp_accept_t accept, utcp_pre_accept_t pre_accept, utcp_
 	utcp->pre_accept = pre_accept;
 	utcp->send = send;
 	utcp->priv = priv;
-	utcp_set_mtu(utcp, DEFAULT_MTU);
 	utcp->timeout = DEFAULT_USER_TIMEOUT; // sec
-	utcp->rto = START_RTO; // usec
 
 	return utcp;
 }
@@ -2266,10 +2284,10 @@ void utcp_reset_timers(struct utcp *utcp) {
 		}
 
 		c->rtt_start.tv_sec = 0;
-	}
 
-	if(utcp->rto > START_RTO) {
-		utcp->rto = START_RTO;
+		if(c->rto > START_RTO) {
+			c->rto = START_RTO;
+		}
 	}
 }
 
@@ -2315,7 +2333,7 @@ void utcp_set_sndbuf(struct utcp_connection *c, size_t size) {
 		c->sndbuf.maxsize = -1;
 	}
 
-	c->do_poll = buffer_free(&c->sndbuf);
+	c->do_poll = is_reliable(c) && buffer_free(&c->sndbuf);
 }
 
 size_t utcp_get_rcvbuf(struct utcp_connection *c) {
@@ -2383,7 +2401,7 @@ void utcp_set_recv_cb(struct utcp_connection *c, utcp_recv_t recv) {
 void utcp_set_poll_cb(struct utcp_connection *c, utcp_poll_t poll) {
 	if(c) {
 		c->poll = poll;
-		c->do_poll = buffer_free(&c->sndbuf);
+		c->do_poll = is_reliable(c) && buffer_free(&c->sndbuf);
 	}
 }
 
@@ -2436,12 +2454,16 @@ void utcp_offline(struct utcp *utcp, bool offline) {
 			}
 
 			utcp->connections[i]->rtt_start.tv_sec = 0;
+
+			if(c->rto > START_RTO) {
+				c->rto = START_RTO;
+			}
 		}
 	}
+}
 
-	if(!offline && utcp->rto > START_RTO) {
-		utcp->rto = START_RTO;
-	}
+void utcp_set_retransmit_cb(struct utcp *utcp, utcp_retransmit_t retransmit) {
+	utcp->retransmit = retransmit;
 }
 
 void utcp_set_clock_granularity(long granularity) {