#15639 [Sus]: detecting end of UDP packets

ID: 15639 Updated by: pollita@php.net Reported By: rip at undernet dot org Status: Suspended Bug Type: *Network Functions Operating System: All PHP Version: 4.1.1 New Comment: The FIRST call to recv() detects end of packet just fine. The trouble is, php_stream_read, in its exuberance to fill the read buffer, makes a SECOND call to php_stream_fill_read_buffer, which in turn makes a SECOND call to php_sockops_read (via stream->ops->read()) and it's THAT call which is waiting for a second packet. This is *bad* behavior for UDP read operations, is there some way we can tell php_sockop_read if this is the initial call or a subsequent backfill? Previous Comments: ------------------------------------------------------------------------ [2002-09-26 10:30:01] wez@php.net If someone comes up with some sample C code that definitely has the behaviour, I will implement it into PHP. Until then this is suspended. ------------------------------------------------------------------------ [2002-04-14 13:09:17] rip at undernet dot org Doesn't seems to change anything. ------------------------------------------------------------------------ [2002-04-13 18:09:59] wez@php.net Can you try changing the FG(def_chunk_size) assignment in the file_globals_ctor function in ext/standard/file.c and hard-code it to 1. Then try your UDP script. If that solves the problem, I will add a method of setting this from script (using set_file_buffer). I still don't think using recvfrom will make any difference. ------------------------------------------------------------------------ [2002-03-16 14:51:31] rip at undernet dot org It also says it should only be used in connected sockets. Here is a working exemple from a porky sourcecode I have : loop: len = recvfrom(sock, data, 50, 0, (struct sockaddr *)&sai, &s_sai); printf("%d bytes from %s:%d - %s\n",len,inet_ntoa(sai.sin_addr),ntohs(sai.sin_port),data); goto loop; The default size is 50, if the UDP packet is < 50 (ie:42) it will print : 42 bytes from 192.168.0.1:8000 - This is only a test. This is only a test!! So if you modify the recv call to a recvfrom call, it won't break TCP and will make UDP work a better way. ------------------------------------------------------------------------ [2002-03-16 12:16:29] wez@php.net My man page says that recv is identical to recvfrom with a NULL from parameter, so I don't see how this can fix it. I still don't think this is technically possible over UDP. If you can show me some real working C code where it works, I will implement it. ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/15639 -- Edit this bug report at http://bugs.php.net/?id=15639&edit=1