[patch] patch from pilot-link bugs sight

net_tickle_patch (text/plain), 4.61 KB, created by Michael W. Holdeman on 2004-09-21 17:25:48 UTC

This fixes a bug where a tickle sent by the other end would
cause net_rx to return prematurely.  This bug showed itself in
pi-nredir: when the server sent a tickle to pi-nredir, net_rx in
pi-nredir returned zero because it had received a zero-length packet;
but when net_rx returns zero that means the connection has been
closed, so pi-nredir exited.

*** net.c	2004/03/13 18:52:43	1.1
--- net.c	2004/03/13 19:54:13
***************
*** 179,187 ****
  	bytes = next->write(ps, buf, PI_NET_HEADER_LEN, flags);
  	if (bytes < PI_NET_HEADER_LEN)
  		return bytes;
! 	bytes = next->write(ps, msg, len, flags);
! 	if (bytes < len)
  		return bytes;
  
  	CHECK(PI_DBG_NET, PI_DBG_LVL_INFO, net_dump_header(buf, 1));
  	CHECK(PI_DBG_NET, PI_DBG_LVL_DEBUG, dumpdata(msg, len));
--- 179,189 ----
  	bytes = next->write(ps, buf, PI_NET_HEADER_LEN, flags);
  	if (bytes < PI_NET_HEADER_LEN)
  		return bytes;
! 	if (len > 0) { /* avoid zero-length write on tickle  */
! 	    bytes = next->write(ps, msg, len, flags);
! 	    if (bytes < len)
  		return bytes;
+ 	}
  
  	CHECK(PI_DBG_NET, PI_DBG_LVL_INFO, net_dump_header(buf, 1));
  	CHECK(PI_DBG_NET, PI_DBG_LVL_DEBUG, dumpdata(msg, len));
***************
*** 196,202 ****
  		total_bytes, 
  		packet_len,
  		timeout,
! 		size;
  	
  	struct 	pi_protocol *prot, *next;
  	struct 	pi_net_data *data;
--- 198,205 ----
  		total_bytes, 
  		packet_len,
  		timeout,
! 		size,
! 		done;
  	
  	struct 	pi_protocol *prot, *next;
  	struct 	pi_net_data *data;
***************
*** 216,255 ****
  	pi_setsockopt(ps->sd, PI_LEVEL_DEV, PI_DEV_TIMEOUT, 
  		      &timeout, &size);
  
! 	total_bytes = 0;
! 	if (data->txid == 0) {	
  		/* Peek to see if it is a headerless packet */
  		bytes = next->read(ps, msg, 1, flags);
  		if (bytes > 0) {
! 			LOG ((PI_DBG_NET, PI_DBG_LVL_INFO,
! 			     "NET RX: Checking for headerless packet %d\n", msg[0]));
  
! 			if (msg[0] == 0x90) {
! 				/* Cause the header bytes to be skipped */
! 				LOG ((PI_DBG_NET, PI_DBG_LVL_INFO,
! 				     "NET RX: Headerless packet\n"));
! 				total_bytes = PI_NET_HEADER_LEN;
! 				msg[PI_NET_OFFSET_TYPE] = PI_NET_TYPE_DATA;
! 				msg[PI_NET_OFFSET_TXID] = 0x01;
! 				set_long (&msg[PI_NET_OFFSET_SIZE], 21);
! 			} else {
! 				total_bytes += bytes;
! 			}
  		} else {
! 			return bytes;
  		}
! 	}
  	
! 	/* Bytes in what's left of the header */
! 	while (total_bytes < PI_NET_HEADER_LEN) {
  		bytes = next->read(ps, msg + total_bytes, PI_NET_HEADER_LEN - total_bytes, flags);
  		if (bytes <= 0)
! 			return bytes;
  		total_bytes += bytes;
  	}
  
  	/* Bytes in the rest of the packet */
- 	packet_len = get_long(&msg[PI_NET_OFFSET_SIZE]);
  	while (total_bytes < PI_NET_HEADER_LEN + packet_len) {
  		bytes = next->read(ps, msg + total_bytes, 
  				  PI_NET_HEADER_LEN + packet_len - total_bytes, flags);
--- 219,278 ----
  	pi_setsockopt(ps->sd, PI_LEVEL_DEV, PI_DEV_TIMEOUT, 
  		      &timeout, &size);
  
! 	done = 0;
! 	while (!done) {
! 	    total_bytes = 0;
! 	    if (data->txid == 0) {	
  		/* Peek to see if it is a headerless packet */
  		bytes = next->read(ps, msg, 1, flags);
  		if (bytes > 0) {
! 		    LOG ((PI_DBG_NET, PI_DBG_LVL_INFO,
! 			  "NET RX: Checking for headerless packet %d\n", msg[0]));
  
! 		    if (msg[0] == 0x90) {
! 			/* Cause the header bytes to be skipped */
! 			LOG ((PI_DBG_NET, PI_DBG_LVL_INFO,
! 			      "NET RX: Headerless packet\n"));
! 			total_bytes = PI_NET_HEADER_LEN;
! 			msg[PI_NET_OFFSET_TYPE] = PI_NET_TYPE_DATA;
! 			msg[PI_NET_OFFSET_TXID] = 0x01;
! 			set_long (&msg[PI_NET_OFFSET_SIZE], 21);
! 		    } else {
! 			total_bytes += bytes;
! 		    }
  		} else {
! 		    return bytes;
  		}
! 	    }
  	
! 	    /* Bytes in what's left of the header */
! 	    while (total_bytes < PI_NET_HEADER_LEN) {
  		bytes = next->read(ps, msg + total_bytes, PI_NET_HEADER_LEN - total_bytes, flags);
  		if (bytes <= 0)
! 		    return bytes;
  		total_bytes += bytes;
+ 	    }
+ 	    packet_len = get_long(&msg[PI_NET_OFFSET_SIZE]);
+ 	    data->type = msg[PI_NET_OFFSET_TYPE];
+ 	    switch (data->type) {
+ 	    case PI_NET_TYPE_TCKL:
+ 		    if (packet_len != 0) {
+ 			    LOG ((PI_DBG_NET, PI_DBG_LVL_ERR,
+ 				  "NET RX: tickle packet with non-zero length\n"));
+ 			    return -1;
+ 		    }
+ 		    /* valid tickle packet; continue reading. */
+ 		    break;
+ 	    case PI_NET_TYPE_DATA:
+ 		    done = 1;
+ 		    break;
+ 	    default:
+ 		    LOG ((PI_DBG_NET, PI_DBG_LVL_ERR,
+ 			  "NET RX: Unknown packet type\n"));
+ 	    }
  	}
  
  	/* Bytes in the rest of the packet */
  	while (total_bytes < PI_NET_HEADER_LEN + packet_len) {
  		bytes = next->read(ps, msg + total_bytes, 
  				  PI_NET_HEADER_LEN + packet_len - total_bytes, flags);