msg_parser.c

Sofia SIP is an open-source SIP User-Agent library, compliant with the IETF RFC3261 specification.

/*
 * This file is part of the Sofia-SIP package
 *
 * Copyright (C) 2005 Nokia Corporation.
 *
 * Contact: Pekka Pessi <[e-mail]>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

/**@ingroup msg_parser
 * @CFILE msg_parser.c
 *
 * HTTP-like message parser engine.
 *
 * @author Pekka Pessi <[e-mail]>
 *
 * @date Created: Thu Oct  5 14:01:24 2000 ppessi
 *
 */

/*#define NDEBUG*/

#include "config.h"

#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
#include <limits.h>
#include <errno.h>

#include <stdarg.h>
#include <sofia-sip/su_tagarg.h>

#include <sofia-sip/su.h>
#include <sofia-sip/su_alloc.h>

#include "msg_internal.h"
#include "sofia-sip/msg_header.h"
#include "sofia-sip/bnf.h"
#include "sofia-sip/msg_parser.h"
#include "sofia-sip/msg_mclass.h"
#include "sofia-sip/msg_mclass_hash.h"
#include "sofia-sip/msg_mime.h"

#if HAVE_FUNC
#elif HAVE_FUNCTION
#define __func__ __FUNCTION__
#else
static char const __func__[] = "msg_parser";
#endif

static int _msg_header_add_dup_as(msg_t *msg,
				  msg_pub_t *pub,
				  msg_hclass_t *hc,
				  msg_header_t const *src);

static void msg_insert_chain(msg_t *msg, msg_pub_t *pub, int prepend,
			     msg_header_t **head, msg_header_t *h);
static void msg_insert_here_in_chain(msg_t *msg,
				     msg_header_t **prev,
				     msg_header_t *h);
su_inline msg_header_t *msg_chain_remove(msg_t *msg, msg_header_t *h);

#ifndef NDEBUG
static int msg_chain_loop(msg_header_t const *h);
static int msg_chain_errors(msg_header_t const *h);
#endif

/* ====================================================================== */
/* Message properties */

/** Get message flags. */
unsigned msg_get_flags(msg_t const *msg, unsigned mask)
{
  return msg ? msg->m_object->msg_flags & mask : 0;
}

/** Set message flags. */
unsigned msg_set_flags(msg_t *msg, unsigned mask)
{
  return msg ? msg->m_object->msg_flags |= mask : 0;
}

/** Clear message flags. */
unsigned msg_zap_flags(msg_t *msg, unsigned mask)
{
  return msg ? msg->m_object->msg_flags &= ~mask : 0;
}

/** Test if streaming is in progress. */
int msg_is_streaming(msg_t const *msg)
{
  return msg && msg->m_streaming != 0;
}

/** Enable/disable streaming */
void msg_set_streaming(msg_t *msg, enum msg_streaming_status what)
{
  if (msg)
    msg->m_streaming = what != 0;
}

/* ---------------------------------------------------------------------- */

/** Test if header is not in the chain */
#define msg_header_is_removed(h) ((h)->sh_prev == NULL)

su_inline int msg_is_request(msg_header_t const *h)
{
  return h->sh_class->hc_hash == msg_request_hash;
}

su_inline int msg_is_status(msg_header_t const *h)
{
  return h->sh_class->hc_hash == msg_status_hash;
}

/* ====================================================================== */
/* Message buffer management */

/** Allocate a buffer of @a size octets, with slack of #msg_min_size. */
void *msg_buf_alloc(msg_t *msg, usize_t size)
{
  struct msg_mbuffer_s *mb = msg->m_buffer;
  size_t room = mb->mb_size - mb->mb_commit - mb->mb_used;
  size_t target_size;

  if (mb->mb_data && room >= (unsigned)size)
    return mb->mb_data + mb->mb_used + mb->mb_commit;

  target_size =
    msg_min_size * ((size + mb->mb_commit) / msg_min_size + 1) - mb->mb_commit;

  return msg_buf_exact(msg, target_size);
}

/** Allocate a buffer exactly of @a size octets, without any slack. */
void *msg_buf_exact(msg_t *msg, usize_t size)
{
  struct msg_mbuffer_s *mb = msg->m_buffer;
  size_t room = mb->mb_size - mb->mb_commit - mb->mb_used;
  char *buffer;
  int realloc;

  if (mb->mb_data && room >= (unsigned)size)
    return mb->mb_data + mb->mb_used + mb->mb_commit;

  size += mb->mb_commit;

  if (msg->m_maxsize && msg->m_size + size > msg->m_maxsize + 1) {
    msg->m_object->msg_flags |= MSG_FLG_TOOLARGE;
    errno = msg->m_errno = ENOBUFS;
    return NULL;
  }

  realloc = !mb->mb_used && !msg->m_set_buffer;

  if (realloc)
    buffer = su_realloc(msg->m_home, mb->mb_data, size);
  else
    buffer = su_alloc(msg->m_home, size);

  if (!buffer)
    return NULL;

  if (!realloc && mb->mb_commit && mb->mb_data)
    memcpy(buffer, mb->mb_data + mb->mb_used, mb->mb_commit);

  msg->m_set_buffer = 0;

  mb->mb_data = buffer;
  mb->mb_size = size;
  mb->mb_used = 0;

  return buffer + mb->mb_commit;
}

/** Commit data into buffer. */
usize_t msg_buf_commit(msg_t *msg, usize_t size, int eos)
{
  if (msg) {
    struct msg_mbuffer_s *mb = msg->m_buffer;
    assert(mb->mb_used + mb->mb_commit + size <= mb->mb_size);

    mb->mb_commit += size;
    mb->mb_eos = eos;

    if (mb->mb_used == 0 && !msg->m_chunk && !msg->m_set_buffer) {
      size_t slack = mb->mb_size - mb->mb_commit;

      if (eos || slack >= msg_min_size) {
	/* realloc and cut down buffer */
	size_t new_size;
	void *new_data;
	
	if (eos)
	  new_size = mb->mb_commit + 1;
	else
	  new_size = mb->mb_commit + msg_min_size;

	new_data = su_realloc(msg->m_home, mb->mb_data, new_size);
	if (new_data) {
	  mb->mb_data = new_data, mb->mb_size = new_size;
	}
      }
    }
  }
  return 0;
}

/** Get length of committed data */
usize_t msg_buf_committed(msg_t const *msg)
{
  if (msg)
    return msg->m_buffer->mb_commit;
  else
    return 0;
}

/** Get committed data */
void *msg_buf_committed_data(msg_t const *msg)
{
  return msg && msg->m_buffer->mb_data ?
    msg->m_buffer->mb_data + msg->m_buffer->mb_used
    : NULL;
}

usize_t msg_buf_size(msg_t const *msg)
{
  assert(msg);
  if (msg) {
    struct msg_mbuffer_s const *mb = msg->m_buffer;
    return mb->mb_size - mb->mb_commit - mb->mb_used;
  }
  else
    return 0;
}

su_inline
void msg_buf_used(msg_t *msg, usize_t used)
{
  msg->m_size += used;
  msg->m_buffer->mb_used += used;
  if (msg->m_buffer->mb_commit > used)
    msg->m_buffer->mb_commit -= used;
  else
    msg->m_buffer->mb_commit = 0;
}

/** Set buffer. */
void msg_buf_set(msg_t *msg, void *b, usize_t size)
{
  if (msg) {
    struct msg_mbuffer_s *mb = msg->m_buffer;

    assert(!msg->m_set_buffer);	/* This can be set only once */

    mb->mb_data = b;
    mb->mb_size = size;
    mb->mb_used = 0;
    mb->mb_commit = 0;
    mb->mb_eos  = 0;

    msg->m_set_buffer = 1;
  }
}

/** Move unparsed data from src to dst */
void *msg_buf_move(msg_t *dst, msg_t const *src)
{
  void *retval;
  struct msg_mbuffer_s *db = dst->m_buffer;
  struct msg_mbuffer_s const *sb = src->m_buffer;

  if (!dst || !src)
    return NULL;

  if (sb->mb_eos)
    retval = msg_buf_exact(dst, sb->mb_commit + 1);
  else
    retval = msg_buf_alloc(dst, sb->mb_commit + 1);

  if (retval == NULL)
    return NULL;

  memcpy(retval, sb->mb_data + sb->mb_used, sb->mb_commit);

  db->mb_commit += sb->mb_commit;
  db->mb_eos = sb->mb_eos;

  return retval;
}

/**Obtain I/O vector for receiving the data.
 *
 * @relatesalso msg_s
 *
 * Allocate buffers for receiving @a n bytes
 * of data available from network. Function returns the buffers in the I/O vector
 * @a vec. The @a vec is allocated by the caller, the available length is
 * given as @a veclen. If the protocol is message-oriented like UDP or SCTP
 * and the available data ends at message boundary, the caller should set
 * the @a exact as 1. Otherwise some extra buffer (known as @em slack) is
 * allocated).
 *
 * Currently, the msg_recv_iovec() allocates receive buffers in at most two
 * blocks, so the caller should allocate at least two elements for the I/O
 * vector @a vec.
 *
 * @param[in]  msg     message object 
 * @param[out] vec     I/O vector 
 * @param[in]  veclen  available length of @a vec 
 * @param[in]  n       number of possibly available bytes