X-Git-Url: http://git.meshlink.io/?p=utcp;a=blobdiff_plain;f=utcp.c;h=04d2b194c20f193aa44f2d4006b9afc1bd356b29;hp=75d4f83417a3be30bccc6346757abef8f7643585;hb=HEAD;hpb=9809749c054e9beb9b01aa4e7e2f597871da133c

diff --git a/utcp.c b/utcp.c
index 75d4f83..04d2b19 100644
--- a/utcp.c
+++ b/utcp.c
@@ -268,7 +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;
 	}
@@ -305,7 +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;
 	}
@@ -322,7 +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;
@@ -334,20 +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;
@@ -355,7 +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);
 	}
 }
 
@@ -365,7 +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;
 	}
 
@@ -401,7 +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.
@@ -816,7 +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)) {
@@ -848,13 +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;
@@ -886,8 +888,6 @@ static void fast_retransmit(struct utcp_connection *c) {
 	default:
 		break;
 	}
-
-	free(pkt);
 }
 
 static void retransmit(struct utcp_connection *c) {
@@ -899,6 +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[];
@@ -1114,7 +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.
@@ -1133,7 +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;
 	}
@@ -1161,7 +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;
@@ -1351,6 +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;
@@ -1594,7 +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
@@ -1709,7 +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++;
@@ -1718,7 +1731,6 @@ skip_ack:
 				set_state(c, ESTABLISHED);
 			}
 
-			// TODO: notify application of this somehow.
 			break;
 
 		case SYN_RECEIVED:
@@ -1732,8 +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
@@ -1741,9 +1753,6 @@ skip_ack:
 #endif
 			return 0;
 		}
-
-		// SYN counts as one sequence number
-		c->rcv.nxt++;
 	}
 
 	// 6. Process new data
@@ -2165,6 +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);
@@ -2175,7 +2191,6 @@ 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
 
 	return utcp;
@@ -2318,7 +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) {
@@ -2386,7 +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);
 	}
 }
 
@@ -2447,6 +2462,10 @@ void utcp_offline(struct utcp *utcp, bool offline) {
 	}
 }
 
+void utcp_set_retransmit_cb(struct utcp *utcp, utcp_retransmit_t retransmit) {
+	utcp->retransmit = retransmit;
+}
+
 void utcp_set_clock_granularity(long granularity) {
 	CLOCK_GRANULARITY = granularity;
 }