Better method of reading data from peers. btpd could send data to peers

that had closed the at least one direction of the connection. That feature
was probably unneccesary. Removed it for now.

btpd/net.c

@@ -112,10 +112,6 @@ net_write(struct peer *p, unsigned long wmax)
     }
     if (!BTPDQ_EMPTY(&p->outq))
 	event_add(&p->out_ev, WRITE_TIMEOUT);
-    else if (p->flags & PF_WRITE_CLOSE) {
-	btpd_log(BTPD_L_CONN, "Closed because of write flag.\n");
-	peer_kill(p);
-    }
 
     return nwritten;
 }
@@ -128,12 +124,12 @@ net_set_state(struct peer *p, int state, size_t size)
 }
 
 static int
-net_dispatch_msg(struct peer *p, uint32_t mlen, uint8_t mnum, uint8_t *buf)
+net_dispatch_msg(struct peer *p, uint8_t *buf)
 {
     uint32_t index, begin, length;
     int res = 0;
 
-    switch (mnum) {
+    switch (p->msg_num) {
     case MSG_CHOKE:
 	peer_on_choke(p);
 	break;
@@ -147,16 +143,16 @@ net_dispatch_msg(struct peer *p, uint32_t mlen, uint8_t mnum, uint8_t *buf)
 	peer_on_uninterest(p);
 	break;
     case MSG_HAVE:
-	peer_on_have(p, net_read32(buf + 5));
+	peer_on_have(p, net_read32(buf));
 	break;
     case MSG_BITFIELD:
-	peer_on_bitfield(p, buf + 5);
+	peer_on_bitfield(p, buf);
 	break;
     case MSG_REQUEST:
 	if ((p->flags & (PF_P_WANT|PF_I_CHOKE)) == PF_P_WANT) {
-	    index = net_read32(buf + 5);
-	    begin = net_read32(buf + 9);
-	    length = net_read32(buf + 13);
+	    index = net_read32(buf);
+	    begin = net_read32(buf + 4);
+	    length = net_read32(buf + 8);
 	    if ((length > PIECE_BLOCKLEN
 		    || index >= p->tp->meta.npieces
 		    || !has_bit(p->tp->piece_field, index)
@@ -168,16 +164,16 @@ net_dispatch_msg(struct peer *p, uint32_t mlen, uint8_t mnum, uint8_t *buf)
 	}
 	break;
     case MSG_CANCEL:
-	index = net_read32(buf + 5);
-	begin = net_read32(buf + 9);
-	length = net_read32(buf + 13);
+	index = net_read32(buf);
+	begin = net_read32(buf + 4);
+	length = net_read32(buf + 8);
 	peer_on_cancel(p, index, begin, length);
 	break;
     case MSG_PIECE:
-	index = net_read32(buf + 5);
-	begin = net_read32(buf + 9);
-	length = mlen - 9;
-	peer_on_piece(p, index, begin, length, buf + 13);
+	index = net_read32(buf);
+	begin = net_read32(buf + 4);
+	length = p->msg_len - 9;
+	peer_on_piece(p, index, begin, length, buf + 8);
 	break;
     default:
 	abort();
@@ -186,9 +182,10 @@ net_dispatch_msg(struct peer *p, uint32_t mlen, uint8_t mnum, uint8_t *buf)
 }
 
 static int
-net_mh_ok(struct peer *p, uint32_t mlen, uint8_t mnum)
+net_mh_ok(struct peer *p)
 {
-    switch (mnum) {
+    uint32_t mlen = p->msg_len;
+    switch (p->msg_num) {
     case MSG_CHOKE:
     case MSG_UNCHOKE:
     case MSG_INTEREST:
@@ -218,20 +215,15 @@ net_progress(struct peer *p, size_t length)
 }
 
 static int
-net_state_foo(struct peer *p, struct io_buffer *iob)
+net_state(struct peer *p, struct io_buffer *iob)
 {
-    uint32_t mlen;
-    uint32_t mnum;
-
     switch (p->net_state) {
     case SHAKE_PSTR:
-	assert(iob->buf_len >= 28);
 	if (bcmp(iob->buf, "\x13""BitTorrent protocol", 20) != 0)
 	    goto bad;
 	net_set_state(p, SHAKE_INFO, 20);
 	return 28;
     case SHAKE_INFO:
-	assert(iob->buf_len >= 20);
 	if (p->flags & PF_INCOMING) {
 	    struct torrent *tp = torrent_get_by_hash(iob->buf);
 	    if (tp == NULL)
@@ -243,7 +235,6 @@ net_state_foo(struct peer *p, struct io_buffer *iob)
 	net_set_state(p, SHAKE_ID, 20);
 	return 20;
     case SHAKE_ID:
-	assert(iob->buf_len >= 20);
 	if ((torrent_has_peer(p->tp, iob->buf)
 		|| bcmp(iob->buf, btpd.peer_id, 20) == 0))
 	    goto bad;
@@ -262,43 +253,35 @@ net_state_foo(struct peer *p, struct io_buffer *iob)
 	net_set_state(p, NET_MSGSIZE, 4);
 	return 20;
     case NET_MSGSIZE:
-	assert(iob->buf_len >= 4);
-	if (bcmp(iob->buf, "\0\0\0\0", 4) == 0)
-	    return 4;
-	else {
-	    net_set_state(p, NET_MSGHEAD, 5);
-	    return 0;
-	}
+	p->msg_len = net_read32(iob->buf);
+	if (p->msg_len != 0)
+	    net_set_state(p, NET_MSGHEAD, 1);
+	return 4;
     case NET_MSGHEAD:
-	assert(iob->buf_len >= 5);
-	mlen = net_read32(iob->buf);
-	mnum = iob->buf[4];
-	if (!net_mh_ok(p, mlen, mnum)) {
+	p->msg_num = iob->buf[0];
+	if (!net_mh_ok(p)) {
 	    btpd_log(BTPD_L_ERROR, "error in head\n");
 	    goto bad;
-	} else if (mlen == 1) {
-	    if (net_dispatch_msg(p, mlen, mnum, iob->buf) != 0) {
+	} else if (p->msg_len == 1) {
+	    if (net_dispatch_msg(p, iob->buf) != 0) {
 		btpd_log(BTPD_L_ERROR, "error in dispatch\n");
 		goto bad;
-		}
+	    }
 	    net_set_state(p, NET_MSGSIZE, 4);
-	    return 5;
 	} else {
-	    uint8_t nstate = mnum == MSG_PIECE ? NET_MSGPIECE : NET_MSGBODY;
-	    net_set_state(p, nstate, mlen + 4);
-	    return 0;
+	    uint8_t nstate =
+		p->msg_num == MSG_PIECE ? NET_MSGPIECE : NET_MSGBODY;
+	    net_set_state(p, nstate, p->msg_len - 1);
 	}
+	return 1;
     case NET_MSGPIECE:
     case NET_MSGBODY:
-	mlen = net_read32(iob->buf);
-	mnum = iob->buf[4];
-	assert(iob->buf_len >= mlen + 4);
-	if (net_dispatch_msg(p, mlen, mnum, iob->buf) != 0) {
+	if (net_dispatch_msg(p, iob->buf) != 0) {
 	    btpd_log(BTPD_L_ERROR, "error in dispatch\n");
 	    goto bad;
 	}
 	net_set_state(p, NET_MSGSIZE, 4);
-	return mlen + 4;
+	return p->msg_len - 1;
     default:
 	abort();
     }
@@ -314,23 +297,25 @@ bad:
 static unsigned long
 net_read(struct peer *p, unsigned long rmax)
 {
-    size_t baggage = p->net_in.buf_len;
-    char buf[GRBUFLEN + baggage];
-    struct io_buffer sbuf = { baggage, sizeof(buf), buf };
-    if (baggage > 0) {
-	bcopy(p->net_in.buf, buf, baggage);
-	free(p->net_in.buf);
-	p->net_in.buf = NULL;
-	p->net_in.buf_off = 0;
-	p->net_in.buf_len = 0;
-    }
+    size_t rest = p->net_in.buf_len - p->net_in.buf_off;
+    char buf[GRBUFLEN];
+    struct iovec iov[2] = {
+	{
+	    p->net_in.buf + p->net_in.buf_off,
+	    rest
+	}, {
+	    buf,
+	    sizeof(buf)
+	}
+    };
 
-    if (rmax > 0)
-	rmax = min(rmax, sbuf.buf_len - sbuf.buf_off);
-    else
-	rmax = sbuf.buf_len - sbuf.buf_off;
+    if (rmax > 0) {
+	if (iov[0].iov_len > rmax)
+	    iov[0].iov_len = rmax;
+	iov[1].iov_len = min(rmax - iov[0].iov_len, iov[1].iov_len);
+    }
 
-    ssize_t nread = read(p->sd, sbuf.buf + sbuf.buf_off, rmax);
+    ssize_t nread = readv(p->sd, iov, 2);
     if (nread < 0 && errno == EAGAIN)
 	goto out;
     else if (nread < 0) {
@@ -343,23 +328,36 @@ net_read(struct peer *p, unsigned long rmax)
 	return 0;
     }
 
-    sbuf.buf_len = sbuf.buf_off + nread;
-    sbuf.buf_off = 0;
-    while (p->state_bytes <= sbuf.buf_len) {
-	ssize_t chomped = net_state_foo(p, &sbuf);
-	if (chomped < 0)
+    if (rest > 0) {
+	if (nread < rest) {
+	    p->net_in.buf_off += nread;
+	    net_progress(p, nread);
+	    goto out;
+	}
+	net_progress(p, rest);
+	if (net_state(p, &p->net_in) < 0)
 	    return nread;
-	sbuf.buf += chomped;
-	sbuf.buf_len -= chomped;
-	baggage = 0;
+	free(p->net_in.buf);
+	bzero(&p->net_in, sizeof(p->net_in));
     }
 
-    net_progress(p, sbuf.buf_len - baggage);
+    struct io_buffer iob = { 0, nread - rest, buf };
+
+    while (p->state_bytes <= iob.buf_len) {
+	net_progress(p, p->state_bytes);
+	ssize_t chomped = net_state(p, &iob);
+	if (chomped < 0)
+	    return nread;
+	iob.buf += chomped;
+	iob.buf_len -= chomped;
+    }
 
-    if (sbuf.buf_len > 0) {
-	p->net_in = sbuf;
-	p->net_in.buf = btpd_malloc(sbuf.buf_len);
-	bcopy(sbuf.buf, p->net_in.buf, sbuf.buf_len);
+    if (iob.buf_len > 0) {
+	net_progress(p, iob.buf_len);
+	p->net_in.buf_off = iob.buf_len;
+	p->net_in.buf_len = p->state_bytes;
+	p->net_in.buf = btpd_malloc(p->state_bytes);
+	bcopy(iob.buf, p->net_in.buf, iob.buf_len);
     }
 
 out:

btpd/peer.h

@@ -8,9 +8,8 @@
 #define PF_ON_READQ	 0x10
 #define PF_ON_WRITEQ	 0x20
 #define PF_ATTACHED	 0x40
-#define PF_WRITE_CLOSE	 0x80	/* Close connection after writing all data */
-#define PF_NO_REQUESTS	0x100
-#define PF_INCOMING	0x200
+#define PF_NO_REQUESTS	 0x80
+#define PF_INCOMING	0x100
 
 #define RATEHISTORY 20
 #define MAXPIECEMSGS 128
@@ -52,6 +51,8 @@ struct peer {
 
     size_t state_bytes;
     uint8_t net_state;
+    uint8_t msg_num;
+    uint32_t msg_len;
     struct io_buffer net_in;
 
     BTPDQ_ENTRY(peer) cm_entry;