X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=utcp.c;h=391706f1d1abdee0ecf8a8edf7b2dc45f6cdd40d;hb=36555fb967087c22ec8854b4cad158f7d2688c5b;hp=730f12b98e8102a42d85c2d6f1fb55971728beec;hpb=45780e57bcc77d6c5f146dea0bb1924cad25bd83;p=utcp

diff --git a/utcp.c b/utcp.c
index 730f12b..391706f 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>
@@ -31,6 +32,27 @@
 
 #include "utcp_priv.h"
 
+#ifndef EBADMSG
+#define EBADMSG         104
+#endif
+
+#ifndef SHUT_RDWR
+#define SHUT_RDWR 2
+#endif
+
+#ifdef poll
+#undef poll
+#endif
+
+#ifndef timersub
+#define timersub(a, b, r) do {\
+	(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;\
+} while (0)
+#endif
+
 #ifdef UTCP_DEBUG
 #include <stdarg.h>
 
@@ -49,7 +71,7 @@ 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)
@@ -91,14 +113,86 @@ static int32_t seqdiff(uint32_t a, uint32_t b) {
 	return a - b;
 }
 
+// Buffer functions
+// TODO: convert to ringbuffers to avoid memmove() operations.
+
+// Store data into the buffer
+static ssize_t buffer_put(struct buffer *buf, const void *data, size_t len) {
+	if(buf->maxsize <= buf->used)
+		return 0;
+	if(len > buf->maxsize - buf->used)
+		len = buf->maxsize - buf->used;
+	if(len > buf->size - buf->used) {
+		size_t newsize = buf->size;
+		do {
+			newsize *= 2;
+		} while(newsize < buf->used + len);
+		if(newsize > buf->maxsize)
+			newsize = buf->maxsize;
+		char *newdata = realloc(buf->data, newsize);
+		if(!newdata)
+			return -1;
+		buf->data = newdata;
+		buf->size = newsize;
+	}
+	memcpy(buf->data + buf->used, data, len);
+	buf->used += len;
+	return len;
+}
+
+// Get data from the buffer. data can be NULL.
+static ssize_t buffer_get(struct buffer *buf, void *data, size_t len) {
+	if(len > buf->used)
+		len = buf->used;
+	if(data)
+		memcpy(data, buf->data, len);
+	if(len < buf->used)
+		memmove(buf->data, buf->data + len, buf->used - len);
+	buf->used -= len;
+	return len;
+}
+
+// Copy data from the buffer without removing it.
+static ssize_t buffer_copy(struct buffer *buf, void *data, size_t offset, size_t len) {
+	if(offset >= buf->used)
+		return 0;
+	if(offset + len > buf->used)
+		len = buf->used - offset;
+	memcpy(data, buf->data + offset, len);
+	return len;
+}
+
+static bool buffer_init(struct buffer *buf, uint32_t len, uint32_t maxlen) {
+	memset(buf, 0, sizeof *buf);
+	buf->data = malloc(len);
+	if(!len)
+		return false;
+	buf->size = len;
+	buf->maxsize = maxlen;
+	return true;
+}
+
+static void buffer_exit(struct buffer *buf) {
+	free(buf->data);
+	memset(buf, 0, sizeof *buf);
+}
+
+static uint32_t buffer_free(const struct buffer *buf) {
+	return buf->maxsize - buf->used;
+}
+
 // Connections are stored in a sorted list.
 // This gives O(log(N)) lookup time, O(N log(N)) insertion time and O(N) deletion time.
 
 static int compare(const void *va, const void *vb) {
+	assert(va && 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 && b);
+	assert(a->src && b->src);
+
 	int c = (int)a->src - (int)b->src;
 	if(c)
 		return c;
@@ -120,13 +214,14 @@ 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);
+	memmove(cp, cp + 1, (utcp->nconnections - i - 1) * sizeof *cp);
 	utcp->nconnections--;
 
+	buffer_exit(&c->sndbuf);
 	free(c);
 }
 
@@ -165,10 +260,7 @@ static struct utcp_connection *allocate_connection(struct utcp *utcp, uint16_t s
 	if(!c)
 		return NULL;
 
-	c->sndbufsize = DEFAULT_SNDBUFSIZE;
-	c->maxsndbufsize = DEFAULT_MAXSNDBUFSIZE;
-	c->sndbuf = malloc(c->sndbufsize);
-	if(!c->sndbuf) {
+	if(!buffer_init(&c->sndbuf, DEFAULT_SNDBUFSIZE, DEFAULT_MAXSNDBUFSIZE)) {
 		free(c);
 		return NULL;
 	}
@@ -199,6 +291,7 @@ struct utcp_connection *utcp_connect(struct utcp *utcp, uint16_t dst, utcp_recv_
 		return NULL;
 
 	c->recv = recv;
+	c->priv = priv;
 
 	struct hdr hdr;
 
@@ -206,8 +299,9 @@ 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);
 
@@ -235,11 +329,8 @@ void utcp_accept(struct utcp_connection *c, utcp_recv_t recv, void *priv) {
 static void ack(struct utcp_connection *c, bool sendatleastone) {
 	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);
 
-	fprintf(stderr, "ack, left=%d, cwndleft=%d, sendatleastone=%d\n", left, cwndleft, sendatleastone);
-	if(left < 0)
-		abort();
+	assert(left >= 0);
 
 	if(cwndleft <= 0)
 		cwndleft = 0;
@@ -252,23 +343,27 @@ static void ack(struct utcp_connection *c, bool sendatleastone) {
 
 	struct {
 		struct hdr hdr;
-		char data[c->utcp->mtu];
-	} pkt;
+		char data[];
+	} *pkt;
 
-	pkt.hdr.src = c->src;
-	pkt.hdr.dst = c->dst;
-	pkt.hdr.ack = c->rcv.nxt;
-	pkt.hdr.wnd = c->snd.wnd;
-	pkt.hdr.ctl = ACK;
+	pkt = malloc(sizeof pkt->hdr + c->utcp->mtu);
+	if(!pkt->data)
+		return;
+
+	pkt->hdr.src = c->src;
+	pkt->hdr.dst = c->dst;
+	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;
-		pkt.hdr.seq = c->snd.nxt;
+		pkt->hdr.seq = c->snd.nxt;
 
-		memcpy(pkt.data, data, seglen);
+		buffer_copy(&c->sndbuf, pkt->data, seqdiff(c->snd.nxt, c->snd.una), seglen);
 
 		c->snd.nxt += seglen;
-		data += seglen;
 		left -= seglen;
 
 		if(c->state != ESTABLISHED && !left && seglen) {
@@ -276,16 +371,18 @@ static void ack(struct utcp_connection *c, bool sendatleastone) {
 			case FIN_WAIT_1:
 			case CLOSING:
 				seglen--;
-				pkt.hdr.ctl |= FIN;
+				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);
+		print_packet(c->utcp, "send", pkt, sizeof pkt->hdr + seglen);
+		c->utcp->send(c->utcp, pkt, sizeof pkt->hdr + seglen);
 	} while(left);
+
+	free(pkt);
 }
 
 ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) {
@@ -326,44 +423,13 @@ ssize_t utcp_send(struct utcp_connection *c, const void *data, size_t len) {
 		return -1;
 	}
 
-	uint32_t bufused = seqdiff(c->snd.nxt, c->snd.una);
-
-	/* Check our send buffer.
-	 * - If it's big enough, just put the data in there.
-	 * - If not, decide whether to enlarge if possible.
-	 * - Cap len so it doesn't overflow our buffer.
-	 */
-
-	if(len > c->sndbufsize - bufused && c->sndbufsize < c->maxsndbufsize) {
-		uint32_t newbufsize;
-		if(c->sndbufsize > c->maxsndbufsize / 2)
-			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;
-			c->sndbufsize = newbufsize;
-		}
-	}
-
-	if(len > c->sndbufsize - bufused)
-		len = c->sndbufsize - bufused;
-
-	if(!len) {
-		errno == EWOULDBLOCK;
+	len = buffer_put(&c->sndbuf, data, len);
+	if(len <= 0) {
+		errno = EWOULDBLOCK;
 		return 0;
 	}
 
-	memcpy(c->sndbuf + bufused, data, len);
 	c->snd.last += len;
-
 	ack(c, false);
 	return len;
 }
@@ -374,7 +440,7 @@ 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;
@@ -471,6 +537,8 @@ int utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 
 	// It is for an existing connection.
 
+	uint32_t prevrcvnxt = c->rcv.nxt;
+
 	// 1. Drop invalid packets.
 
 	// 1a. Drop packets that should not happen in our current state.
@@ -593,20 +661,35 @@ int utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 	// 3. Advance snd.una
 
 	uint32_t advanced = seqdiff(hdr.ack, c->snd.una);
-	c->snd.una = hdr.ack;
+	prevrcvnxt = c->rcv.nxt;
 
 	if(advanced) {
-		debug("%p advanced %u\n", utcp, advanced);
-		// Make room in the send buffer.
-		// TODO: try to avoid memmoving too much. Circular buffer?
-		uint32_t left = seqdiff(c->snd.nxt, hdr.ack);
-		if(left)
-			memmove(c->sndbuf, c->sndbuf + advanced, left);
+		int32_t data_acked = advanced;
+
+		switch(c->state) {
+			case SYN_SENT:
+			case SYN_RECEIVED:
+				data_acked--;
+				break;
+			// TODO: handle FIN as well.
+			default:
+				break;
+		}
+
+		assert(data_acked >= 0);
+
+		int32_t bufused = seqdiff(c->snd.last, c->snd.una);
+		assert(data_acked <= bufused);
+
+		if(data_acked)
+			buffer_get(&c->sndbuf, NULL, data_acked);
+
+		c->snd.una = hdr.ack;
+
 		c->dupack = 0;
 		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);
+		if(c->snd.cwnd > c->sndbuf.maxsize)
+			c->snd.cwnd = c->sndbuf.maxsize;
 
 		// Check if we have sent a FIN that is now ACKed.
 		switch(c->state) {
@@ -629,7 +712,8 @@ int utcp_recv(struct utcp *utcp, const void *data, size_t 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();
 			}
 		}
 	}
@@ -637,7 +721,7 @@ 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);
 	}
@@ -711,10 +795,14 @@ 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.
+				abort();
+			}
 			if(rxd < 0)
 				rxd = 0;
 			else if(rxd > len)
@@ -757,6 +845,7 @@ 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) {
@@ -765,14 +854,14 @@ int utcp_recv(struct utcp *utcp, const void *data, size_t len) {
 		}
 	}
 
-	if(!len && !advanced)
-		return 0;
-
-	if(!len && !(hdr.ctl & SYN) && !(hdr.ctl & FIN))
-		return 0;
+	// Now we send something back if:
+	// - we advanced rcv.nxt (ie, we got some data that needs to be ACKed)
+	//   -> sendatleastone = true
+	// - or we got an ack, so we should maybe send a bit more data
+	//   -> sendatleastone = false
 
 ack:
-	ack(c, true);
+	ack(c, prevrcvnxt != c->rcv.nxt);
 	return 0;
 
 reset:
@@ -793,7 +882,7 @@ 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;
@@ -841,6 +930,8 @@ int utcp_shutdown(struct utcp_connection *c, int dir) {
 int utcp_close(struct utcp_connection *c) {
 	if(utcp_shutdown(c, SHUT_RDWR))
 		return -1;
+	c->recv = NULL;
+	c->poll = NULL;
 	c->reapable = true;
 	return 0;
 }
@@ -857,6 +948,8 @@ int utcp_abort(struct utcp_connection *c) {
 		return -1;
 	}
 
+	c->recv = NULL;
+	c->poll = NULL;
 	c->reapable = true;
 
 	switch(c->state) {
@@ -903,11 +996,15 @@ static void retransmit(struct utcp_connection *c) {
 
 	struct {
 		struct hdr hdr;
-		char data[c->utcp->mtu];
-	} pkt;
+		char data[];
+	} *pkt;
+
+	pkt = malloc(sizeof pkt->hdr + c->utcp->mtu);
+	if(!pkt)
+		return;
 
-	pkt.hdr.src = c->src;
-	pkt.hdr.dst = c->dst;
+	pkt->hdr.src = c->src;
+	pkt->hdr.dst = c->dst;
 
 	switch(c->state) {
 		case LISTEN:
@@ -915,27 +1012,27 @@ static void retransmit(struct utcp_connection *c) {
 			break;
 
 		case SYN_SENT:
-			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.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);
 			break;
 
 		case SYN_RECEIVED:
-			pkt.hdr.seq = c->snd.nxt;
-			pkt.hdr.ack = c->rcv.nxt;
-			pkt.hdr.ctl = SYN | ACK;
-			print_packet(c->utcp, "rtrx", &pkt, sizeof pkt.hdr);
-			utcp->send(utcp, &pkt, sizeof pkt.hdr);
+			pkt->hdr.seq = c->snd.nxt;
+			pkt->hdr.ack = c->rcv.nxt;
+			pkt->hdr.ctl = SYN | ACK;
+			print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr);
+			utcp->send(utcp, pkt, sizeof pkt->hdr);
 			break;
 
 		case ESTABLISHED:
 		case FIN_WAIT_1:
-			pkt.hdr.seq = c->snd.una;
-			pkt.hdr.ack = c->rcv.nxt;
-			pkt.hdr.ctl = ACK;
+			pkt->hdr.seq = c->snd.una;
+			pkt->hdr.ack = c->rcv.nxt;
+			pkt->hdr.ctl = ACK;
 			uint32_t len = seqdiff(c->snd.nxt, c->snd.una);
 			if(c->state == FIN_WAIT_1)
 				len--;
@@ -943,17 +1040,19 @@ static void retransmit(struct utcp_connection *c) {
 				len = utcp->mtu;
 			else {
 				if(c->state == FIN_WAIT_1)
-					pkt.hdr.ctl |= FIN;
+					pkt->hdr.ctl |= FIN;
 			}
-			memcpy(pkt.data, c->sndbuf, len);
-			print_packet(c->utcp, "rtrx", &pkt, sizeof pkt.hdr + len);
-			utcp->send(utcp, &pkt, sizeof pkt.hdr + len);
+			buffer_copy(&c->sndbuf, pkt->data, 0, len);
+			print_packet(c->utcp, "rtrx", pkt, sizeof pkt->hdr + len);
+			utcp->send(utcp, pkt, sizeof pkt->hdr + len);
 			break;
 
 		default:
 			// TODO: implement
 			abort();
 	}
+
+	free(pkt);
 }
 
 /* Handle timeouts.
@@ -993,6 +1092,9 @@ int 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(timerisset(&c->conn_timeout) && timercmp(&c->conn_timeout, &next, <))
 			next = c->conn_timeout;
 
@@ -1037,8 +1139,13 @@ 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]);
+		buffer_exit(&utcp->connections[i]->sndbuf);
+		free(utcp->connections[i]);
+	}
+	free(utcp->connections);
 	free(utcp);
 }
 
@@ -1060,13 +1167,17 @@ void utcp_set_user_timeout(struct utcp *u, int timeout) {
 }
 
 size_t utcp_get_sndbuf(struct utcp_connection *c) {
-	return c->maxsndbufsize;
+	return c->sndbuf.maxsize;
+}
+
+size_t utcp_get_sndbuf_free(struct utcp_connection *c) {
+	return buffer_free(&c->sndbuf);
 }
 
 void utcp_set_sndbuf(struct utcp_connection *c, size_t size) {
-	c->maxsndbufsize = size;
-	if(c->maxsndbufsize != size)
-		c->maxsndbufsize = -1;
+	c->sndbuf.maxsize = size;
+	if(c->sndbuf.maxsize != size)
+		c->sndbuf.maxsize = -1;
 }
 
 bool utcp_get_nodelay(struct utcp_connection *c) {
@@ -1088,3 +1199,11 @@ void utcp_set_keepalive(struct utcp_connection *c, bool keepalive) {
 size_t utcp_get_outq(struct utcp_connection *c) {
 	return seqdiff(c->snd.nxt, c->snd.una);
 }
+
+void utcp_set_recv_cb(struct utcp_connection *c, utcp_recv_t recv) {
+	c->recv = recv;
+}
+
+void utcp_set_poll_cb(struct utcp_connection *c, utcp_poll_t poll) {
+	c->poll = poll;
+}