1 /* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
5 * Copyright (C) 2011 Data Differential, http://datadifferential.com/
6 * Copyright (C) 2006-2009 Brian Aker
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions are
13 * * Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
16 * * Redistributions in binary form must reproduce the above
17 * copyright notice, this list of conditions and the following disclaimer
18 * in the documentation and/or other materials provided with the
21 * * The names of its contributors may not be used to endorse or
22 * promote products derived from this software without specific prior
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 #include <libmemcached/common.h>
43 enum memc_read_or_write
{
48 static ssize_t
io_flush(memcached_server_write_instance_st ptr
,
49 const bool with_flush
,
50 memcached_return_t
*error
);
51 static void increment_udp_message_id(memcached_server_write_instance_st ptr
);
53 static memcached_return_t
io_wait(memcached_server_write_instance_st ptr
,
54 memc_read_or_write read_or_write
)
62 if (read_or_write
== MEM_WRITE
) /* write */
65 WATCHPOINT_SET(ptr
->io_wait_count
.write
++);
69 WATCHPOINT_SET(ptr
->io_wait_count
.read
++);
73 ** We are going to block on write, but at least on Solaris we might block
74 ** on write if we haven't read anything from our input buffer..
75 ** Try to purge the input buffer if we don't do any flow control in the
76 ** application layer (just sending a lot of data etc)
77 ** The test is moved down in the purge function to avoid duplication of
80 if (read_or_write
== MEM_WRITE
)
82 memcached_return_t rc
= memcached_purge(ptr
);
83 if (rc
!= MEMCACHED_SUCCESS
&& rc
!= MEMCACHED_STORED
)
85 return MEMCACHED_FAILURE
;
90 while (--loop_max
) // While loop is for ERESTART or EINTR
92 if (ptr
->root
->poll_timeout
) // Mimic 0 causes timeout behavior (not all platforms do this)
94 error
= poll(&fds
, 1, ptr
->root
->poll_timeout
);
104 WATCHPOINT_IF_LABELED_NUMBER(read_or_write
&& loop_max
< 4, "read() times we had to loop, decremented down from 5", loop_max
);
105 WATCHPOINT_IF_LABELED_NUMBER(!read_or_write
&& loop_max
< 4, "write() times we had to loop, decremented down from 5", loop_max
);
107 return MEMCACHED_SUCCESS
;
109 case 0: // Timeout occured, we let the while() loop do its thing.
110 return memcached_set_error(*ptr
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
);
113 WATCHPOINT_ERRNO(get_socket_errno());
114 switch (get_socket_errno())
116 #ifdef TARGET_OS_LINUX
124 return memcached_set_error(*ptr
, MEMCACHED_MEMORY_ALLOCATION_FAILURE
, MEMCACHED_AT
);
127 return memcached_set_error(*ptr
, MEMCACHED_MEMORY_ALLOCATION_FAILURE
, MEMCACHED_AT
, memcached_literal_param("RLIMIT_NOFILE exceeded, or if OSX the timeout value was invalid"));
130 if (fds
.revents
& POLLERR
)
133 socklen_t len
= sizeof (err
);
134 (void)getsockopt(ptr
->fd
, SOL_SOCKET
, SO_ERROR
, &err
, &len
);
135 ptr
->cached_errno
= (err
== 0) ? get_socket_errno() : err
;
139 ptr
->cached_errno
= get_socket_errno();
141 memcached_quit_server(ptr
, true);
143 return memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
148 /* Imposssible for anything other then -1 */
149 WATCHPOINT_ASSERT(error
== -1);
150 ptr
->cached_errno
= get_socket_errno();
151 memcached_quit_server(ptr
, true);
153 return memcached_set_error(*ptr
, MEMCACHED_FAILURE
, MEMCACHED_AT
);
156 memcached_return_t
memcached_io_wait_for_write(memcached_server_write_instance_st ptr
)
158 return io_wait(ptr
, MEM_WRITE
);
162 * Try to fill the input buffer for a server with as much
165 * @param ptr the server to pack
167 static bool repack_input_buffer(memcached_server_write_instance_st ptr
)
169 if (ptr
->read_ptr
!= ptr
->read_buffer
)
171 /* Move all of the data to the beginning of the buffer so
172 ** that we can fit more data into the buffer...
174 memmove(ptr
->read_buffer
, ptr
->read_ptr
, ptr
->read_buffer_length
);
175 ptr
->read_ptr
= ptr
->read_buffer
;
176 ptr
->read_data_length
= ptr
->read_buffer_length
;
179 /* There is room in the buffer, try to fill it! */
180 if (ptr
->read_buffer_length
!= MEMCACHED_MAX_BUFFER
)
183 /* Just try a single read to grab what's available */
184 ssize_t nr
= recv(ptr
->fd
,
185 ptr
->read_ptr
+ ptr
->read_data_length
,
186 MEMCACHED_MAX_BUFFER
- ptr
->read_data_length
,
193 switch (get_socket_errno())
202 #ifdef TARGET_OS_LINUX
205 break; // No IO is fine, we can just move on
208 memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
213 case 0: // Shutdown on the socket has occurred
215 memcached_set_error(*ptr
, MEMCACHED_CONNECTION_FAILURE
, MEMCACHED_AT
);
221 ptr
->read_data_length
+= size_t(nr
);
222 ptr
->read_buffer_length
+= size_t(nr
);
233 * If the we have callbacks connected to this server structure
234 * we may start process the input queue and fire the callbacks
235 * for the incomming messages. This function is _only_ called
236 * when the input buffer is full, so that we _know_ that we have
237 * at least _one_ message to process.
239 * @param ptr the server to star processing iput messages for
240 * @return true if we processed anything, false otherwise
242 static bool process_input_buffer(memcached_server_write_instance_st ptr
)
245 ** We might be able to process some of the response messages if we
246 ** have a callback set up
248 if (ptr
->root
->callbacks
!= NULL
&& ptr
->root
->flags
.use_udp
== false)
251 * We might have responses... try to read them out and fire
254 memcached_callback_st cb
= *ptr
->root
->callbacks
;
256 memcached_set_processing_input((memcached_st
*)ptr
->root
, true);
258 char buffer
[MEMCACHED_DEFAULT_COMMAND_SIZE
];
259 memcached_return_t error
;
260 memcached_st
*root
= (memcached_st
*)ptr
->root
;
261 error
= memcached_response(ptr
, buffer
, sizeof(buffer
),
264 memcached_set_processing_input(root
, false);
266 if (error
== MEMCACHED_SUCCESS
)
268 for (unsigned int x
= 0; x
< cb
.number_of_callback
; x
++)
270 error
= (*cb
.callback
[x
])(ptr
->root
, &root
->result
, cb
.context
);
271 if (error
!= MEMCACHED_SUCCESS
)
275 /* @todo what should I do with the error message??? */
277 /* @todo what should I do with other error messages?? */
284 memcached_return_t
memcached_io_read(memcached_server_write_instance_st ptr
,
285 void *buffer
, size_t length
, ssize_t
*nread
)
287 assert(ptr
); // Programmer error
288 char *buffer_ptr
= static_cast<char *>(buffer
);
290 if (ptr
->fd
== INVALID_SOCKET
)
292 assert(int(ptr
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
));
293 return MEMCACHED_CONNECTION_FAILURE
;
298 if (not ptr
->read_buffer_length
)
303 data_read
= recv(ptr
->fd
, ptr
->read_buffer
, MEMCACHED_MAX_BUFFER
, MSG_DONTWAIT
);
304 if (data_read
== SOCKET_ERROR
)
306 switch (get_socket_errno())
308 case EINTR
: // We just retry
311 case ETIMEDOUT
: // OSX
316 #ifdef TARGET_OS_LINUX
319 if (memcached_success(io_wait(ptr
, MEM_READ
)))
323 return MEMCACHED_IN_PROGRESS
;
327 case ENOTCONN
: // Programmer Error
328 WATCHPOINT_ASSERT(0);
330 WATCHPOINT_ASSERT(0);
332 assert(ptr
->fd
!= INVALID_SOCKET
);
338 memcached_quit_server(ptr
, true);
340 return memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
344 else if (data_read
== 0)
347 EOF. Any data received so far is incomplete
348 so discard it. This always reads by byte in case of TCP
349 and protocol enforcement happens at memcached_response()
350 looking for '\n'. We do not care for UDB which requests 8 bytes
351 at once. Generally, this means that connection went away. Since
352 for blocking I/O we do not return 0 and for non-blocking case
353 it will return EGAIN if data is not immediatly available.
355 WATCHPOINT_STRING("We had a zero length recv()");
357 memcached_quit_server(ptr
, true);
359 return memcached_set_error(*ptr
, MEMCACHED_UNKNOWN_READ_FAILURE
, MEMCACHED_AT
);
361 } while (data_read
<= 0);
363 ptr
->io_bytes_sent
= 0;
364 ptr
->read_data_length
= (size_t) data_read
;
365 ptr
->read_buffer_length
= (size_t) data_read
;
366 ptr
->read_ptr
= ptr
->read_buffer
;
373 difference
= (length
> ptr
->read_buffer_length
) ? ptr
->read_buffer_length
: length
;
375 memcpy(buffer_ptr
, ptr
->read_ptr
, difference
);
376 length
-= difference
;
377 ptr
->read_ptr
+= difference
;
378 ptr
->read_buffer_length
-= difference
;
379 buffer_ptr
+= difference
;
383 *buffer_ptr
= *ptr
->read_ptr
;
385 ptr
->read_buffer_length
--;
391 ptr
->server_failure_counter
= 0;
392 *nread
= (ssize_t
)(buffer_ptr
- (char*)buffer
);
393 return MEMCACHED_SUCCESS
;
396 memcached_return_t
memcached_io_slurp(memcached_server_write_instance_st ptr
)
398 assert(ptr
); // Programmer error
400 if (ptr
->fd
== INVALID_SOCKET
)
402 assert(int(ptr
->state
) <= int(MEMCACHED_SERVER_STATE_ADDRINFO
));
403 return MEMCACHED_CONNECTION_FAILURE
;
407 char buffer
[MEMCACHED_MAX_BUFFER
];
410 data_read
= recv(ptr
->fd
, ptr
->read_buffer
, sizeof(buffer
), MSG_DONTWAIT
);
411 if (data_read
== SOCKET_ERROR
)
413 switch (get_socket_errno())
415 case EINTR
: // We just retry
418 case ETIMEDOUT
: // OSX
423 #ifdef TARGET_OS_LINUX
426 if (memcached_success(io_wait(ptr
, MEM_READ
)))
430 return MEMCACHED_IN_PROGRESS
;
434 case ENOTCONN
: // Programmer Error
435 WATCHPOINT_ASSERT(0);
437 WATCHPOINT_ASSERT(0);
439 assert(ptr
->fd
!= INVALID_SOCKET
);
444 return MEMCACHED_CONNECTION_FAILURE
; // We want this!
447 } while (data_read
> 0);
449 return MEMCACHED_CONNECTION_FAILURE
;
452 static ssize_t
_io_write(memcached_server_write_instance_st ptr
,
453 const void *buffer
, size_t length
, bool with_flush
)
455 size_t original_length
;
456 const char* buffer_ptr
;
458 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
460 original_length
= length
;
461 buffer_ptr
= static_cast<const char *>(buffer
);
469 if (ptr
->type
== MEMCACHED_CONNECTION_UDP
)
471 //UDP does not support partial writes
472 buffer_end
= MAX_UDP_DATAGRAM_LENGTH
;
473 should_write
= length
;
474 if (ptr
->write_buffer_offset
+ should_write
> buffer_end
)
481 buffer_end
= MEMCACHED_MAX_BUFFER
;
482 should_write
= buffer_end
- ptr
->write_buffer_offset
;
483 should_write
= (should_write
< length
) ? should_write
: length
;
486 write_ptr
= ptr
->write_buffer
+ ptr
->write_buffer_offset
;
487 memcpy(write_ptr
, buffer_ptr
, should_write
);
488 ptr
->write_buffer_offset
+= should_write
;
489 buffer_ptr
+= should_write
;
490 length
-= should_write
;
492 if (ptr
->write_buffer_offset
== buffer_end
&& ptr
->type
!= MEMCACHED_CONNECTION_UDP
)
494 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
496 memcached_return_t rc
;
497 ssize_t sent_length
= io_flush(ptr
, with_flush
, &rc
);
498 if (sent_length
== -1)
503 /* If io_flush calls memcached_purge, sent_length may be 0 */
504 unlikely (sent_length
!= 0)
506 WATCHPOINT_ASSERT(sent_length
== (ssize_t
)buffer_end
);
513 memcached_return_t rc
;
514 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
515 if (io_flush(ptr
, with_flush
, &rc
) == -1)
521 return (ssize_t
) original_length
;
524 ssize_t
memcached_io_write(memcached_server_write_instance_st ptr
,
525 const void *buffer
, size_t length
, bool with_flush
)
527 return _io_write(ptr
, buffer
, length
, with_flush
);
530 ssize_t
memcached_io_writev(memcached_server_write_instance_st ptr
,
531 const struct libmemcached_io_vector_st
*vector
,
532 size_t number_of
, bool with_flush
)
536 for (size_t x
= 0; x
< number_of
; x
++, vector
++)
540 if ((returnable
= _io_write(ptr
, vector
->buffer
, vector
->length
, false)) == -1)
549 if (memcached_io_write(ptr
, NULL
, 0, true) == -1)
559 void memcached_io_close(memcached_server_write_instance_st ptr
)
561 if (ptr
->fd
== INVALID_SOCKET
)
566 /* in case of death shutdown to avoid blocking at close() */
567 if (shutdown(ptr
->fd
, SHUT_RDWR
) == SOCKET_ERROR
&& get_socket_errno() != ENOTCONN
)
569 WATCHPOINT_NUMBER(ptr
->fd
);
570 WATCHPOINT_ERRNO(get_socket_errno());
571 WATCHPOINT_ASSERT(get_socket_errno());
574 if (closesocket(ptr
->fd
) == SOCKET_ERROR
)
576 WATCHPOINT_ERRNO(get_socket_errno());
578 ptr
->state
= MEMCACHED_SERVER_STATE_NEW
;
579 ptr
->fd
= INVALID_SOCKET
;
582 memcached_server_write_instance_st
memcached_io_get_readable_server(memcached_st
*memc
)
584 #define MAX_SERVERS_TO_POLL 100
585 struct pollfd fds
[MAX_SERVERS_TO_POLL
];
586 unsigned int host_index
= 0;
588 for (uint32_t x
= 0; x
< memcached_server_count(memc
) && host_index
< MAX_SERVERS_TO_POLL
; ++x
)
590 memcached_server_write_instance_st instance
=
591 memcached_server_instance_fetch(memc
, x
);
593 if (instance
->read_buffer_length
> 0) /* I have data in the buffer */
596 if (memcached_server_response_count(instance
) > 0)
598 fds
[host_index
].events
= POLLIN
;
599 fds
[host_index
].revents
= 0;
600 fds
[host_index
].fd
= instance
->fd
;
607 /* We have 0 or 1 server with pending events.. */
608 for (uint32_t x
= 0; x
< memcached_server_count(memc
); ++x
)
610 memcached_server_write_instance_st instance
=
611 memcached_server_instance_fetch(memc
, x
);
613 if (memcached_server_response_count(instance
) > 0)
622 switch (poll(fds
, host_index
, memc
->poll_timeout
))
625 memcached_set_errno(*memc
, get_socket_errno(), MEMCACHED_AT
);
631 for (size_t x
= 0; x
< host_index
; ++x
)
633 if (fds
[x
].revents
& POLLIN
)
635 for (uint32_t y
= 0; y
< memcached_server_count(memc
); ++y
)
637 memcached_server_write_instance_st instance
=
638 memcached_server_instance_fetch(memc
, y
);
640 if (instance
->fd
== fds
[x
].fd
)
650 static ssize_t
io_flush(memcached_server_write_instance_st ptr
,
651 const bool with_flush
,
652 memcached_return_t
*error
)
655 ** We might want to purge the input buffer if we haven't consumed
656 ** any output yet... The test for the limits is the purge is inline
657 ** in the purge function to avoid duplicating the logic..
660 memcached_return_t rc
;
661 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
662 rc
= memcached_purge(ptr
);
664 if (rc
!= MEMCACHED_SUCCESS
&& rc
!= MEMCACHED_STORED
)
670 size_t return_length
;
671 char *local_write_ptr
= ptr
->write_buffer
;
672 size_t write_length
= ptr
->write_buffer_offset
;
674 *error
= MEMCACHED_SUCCESS
;
676 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
678 // UDP Sanity check, make sure that we are not sending somthing too big
679 if (ptr
->type
== MEMCACHED_CONNECTION_UDP
&& write_length
> MAX_UDP_DATAGRAM_LENGTH
)
681 *error
= MEMCACHED_WRITE_FAILURE
;
685 if (ptr
->write_buffer_offset
== 0 || (ptr
->type
== MEMCACHED_CONNECTION_UDP
686 && ptr
->write_buffer_offset
== UDP_DATAGRAM_HEADER_LENGTH
))
691 /* Looking for memory overflows */
693 if (write_length
== MEMCACHED_MAX_BUFFER
)
694 WATCHPOINT_ASSERT(ptr
->write_buffer
== local_write_ptr
);
695 WATCHPOINT_ASSERT((ptr
->write_buffer
+ MEMCACHED_MAX_BUFFER
) >= (local_write_ptr
+ write_length
));
701 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
702 WATCHPOINT_ASSERT(write_length
> 0);
704 if (ptr
->type
== MEMCACHED_CONNECTION_UDP
)
705 increment_udp_message_id(ptr
);
707 WATCHPOINT_ASSERT(ptr
->fd
!= INVALID_SOCKET
);
710 sent_length
= send(ptr
->fd
, local_write_ptr
, write_length
, MSG_NOSIGNAL
|MSG_DONTWAIT
);
714 sent_length
= send(ptr
->fd
, local_write_ptr
, write_length
, MSG_NOSIGNAL
|MSG_DONTWAIT
|MSG_MORE
);
717 if (sent_length
== SOCKET_ERROR
)
719 ptr
->cached_errno
= get_socket_errno();
720 #if 0 // @todo I should look at why we hit this bit of code hard frequently
721 WATCHPOINT_ERRNO(get_socket_errno());
722 WATCHPOINT_NUMBER(get_socket_errno());
724 switch (get_socket_errno())
734 * We may be blocked on write because the input buffer
735 * is full. Let's check if we have room in our input
736 * buffer for more data and retry the write before
739 if (repack_input_buffer(ptr
) or
740 process_input_buffer(ptr
))
745 memcached_return_t rc
= io_wait(ptr
, MEM_WRITE
);
746 if (memcached_success(rc
))
750 else if (rc
== MEMCACHED_TIMEOUT
)
752 *error
= memcached_set_error(*ptr
, MEMCACHED_TIMEOUT
, MEMCACHED_AT
);
756 memcached_quit_server(ptr
, true);
757 *error
= memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
763 memcached_quit_server(ptr
, true);
764 *error
= memcached_set_errno(*ptr
, get_socket_errno(), MEMCACHED_AT
);
765 WATCHPOINT_ASSERT(ptr
->fd
== -1);
770 if (ptr
->type
== MEMCACHED_CONNECTION_UDP
and
771 (size_t)sent_length
!= write_length
)
773 memcached_quit_server(ptr
, true);
774 *error
= memcached_set_error(*ptr
, MEMCACHED_WRITE_FAILURE
, MEMCACHED_AT
);
778 ptr
->io_bytes_sent
+= (uint32_t) sent_length
;
780 local_write_ptr
+= sent_length
;
781 write_length
-= (uint32_t) sent_length
;
782 return_length
+= (uint32_t) sent_length
;
785 WATCHPOINT_ASSERT(write_length
== 0);
786 // Need to study this assert() WATCHPOINT_ASSERT(return_length ==
787 // ptr->write_buffer_offset);
789 // if we are a udp server, the begining of the buffer is reserverd for
790 // the upd frame header
791 if (ptr
->type
== MEMCACHED_CONNECTION_UDP
)
792 ptr
->write_buffer_offset
= UDP_DATAGRAM_HEADER_LENGTH
;
794 ptr
->write_buffer_offset
= 0;
796 return (ssize_t
) return_length
;
800 Eventually we will just kill off the server with the problem.
802 void memcached_io_reset(memcached_server_write_instance_st ptr
)
804 memcached_quit_server(ptr
, true);
808 * Read a given number of bytes from the server and place it into a specific
809 * buffer. Reset the IO channel on this server if an error occurs.
811 memcached_return_t
memcached_safe_read(memcached_server_write_instance_st ptr
,
816 char *data
= static_cast<char *>(dta
);
818 while (offset
< size
)
821 memcached_return_t rc
;
823 while (memcached_continue(rc
= memcached_io_read(ptr
, data
+ offset
, size
- offset
, &nread
))) { };
825 if (memcached_failed(rc
))
830 offset
+= (size_t) nread
;
833 return MEMCACHED_SUCCESS
;
836 memcached_return_t
memcached_io_readline(memcached_server_write_instance_st ptr
,
840 bool line_complete
= false;
843 while (not line_complete
)
845 if (ptr
->read_buffer_length
== 0)
848 * We don't have any data in the buffer, so let's fill the read
849 * buffer. Call the standard read function to avoid duplicating
853 memcached_return_t rc
= memcached_io_read(ptr
, buffer_ptr
, 1, &nread
);
854 if (memcached_failed(rc
) and rc
== MEMCACHED_IN_PROGRESS
)
856 memcached_quit_server(ptr
, true);
857 return memcached_set_error(*ptr
, rc
, MEMCACHED_AT
);
859 else if (memcached_failed(rc
))
864 if (*buffer_ptr
== '\n')
871 /* Now let's look in the buffer and copy as we go! */
872 while (ptr
->read_buffer_length
&& total_nr
< size
&& !line_complete
)
874 *buffer_ptr
= *ptr
->read_ptr
;
875 if (*buffer_ptr
== '\n')
876 line_complete
= true;
877 --ptr
->read_buffer_length
;
883 if (total_nr
== size
)
884 return MEMCACHED_PROTOCOL_ERROR
;
887 return MEMCACHED_SUCCESS
;
891 * The udp request id consists of two seperate sections
893 * 2) The message number
894 * The thread id should only be set when the memcached_st struct is created
895 * and should not be changed.
897 * The message num is incremented for each new message we send, this function
898 * extracts the message number from message_id, increments it and then
899 * writes the new value back into the header
901 static void increment_udp_message_id(memcached_server_write_instance_st ptr
)
903 struct udp_datagram_header_st
*header
= (struct udp_datagram_header_st
*)ptr
->write_buffer
;
904 uint16_t cur_req
= get_udp_datagram_request_id(header
);
905 int msg_num
= get_msg_num_from_request_id(cur_req
);
906 int thread_id
= get_thread_id_from_request_id(cur_req
);
908 if (((++msg_num
) & UDP_REQUEST_ID_THREAD_MASK
) != 0)
911 header
->request_id
= htons((uint16_t) (thread_id
| msg_num
));
914 memcached_return_t
memcached_io_init_udp_header(memcached_server_write_instance_st ptr
, uint16_t thread_id
)
916 if (thread_id
> UDP_REQUEST_ID_MAX_THREAD_ID
)
917 return MEMCACHED_FAILURE
;
919 struct udp_datagram_header_st
*header
= (struct udp_datagram_header_st
*)ptr
->write_buffer
;
920 header
->request_id
= htons((uint16_t) (generate_udp_request_thread_id(thread_id
)));
921 header
->num_datagrams
= htons(1);
922 header
->sequence_number
= htons(0);
924 return MEMCACHED_SUCCESS
;