msg_parser.c

this is simple sip stack.

/*
 * 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);
static 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)

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

static 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, unsigned size)
{
  struct msg_mbuffer_s *mb = msg->m_buffer;
  unsigned room = mb->mb_size - mb->mb_commit - mb->mb_used;
  int 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, unsigned size)
{
  struct msg_mbuffer_s *mb = msg->m_buffer;
  unsigned 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. */
unsigned msg_buf_commit(msg_t *msg, unsigned 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 */
unsigned 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;
}

unsigned 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;
}

static inline
void msg_buf_used(msg_t *msg, unsigned 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, unsigned 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 iovec for receiving the data.
 *
 * @relates msg_s
 *
 * The function msg_recv_iovec() allocates buffers for receiving @a n bytes
 * of data available from network. It 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 buffers in at most two blocks,
 * so the caller should allocate at least two elements for the I/O vector @a
 * vec.
 *
 * @param msg     message object [IN]
 * @param vec     I/O vector [OUT]
 * @param veclen  available length of @a vec [IN]
 * @param n       number of available bytes燵IN]
 * @param exact   true if data ends at message boundary [IN]
 *
 * @return
 * The function msg_recv_iovec() returns the length of I/O vector to
 * receive data, 0 if there are not enough buffers, or -1 upon an error.
 */
int msg_recv_iovec(msg_t *msg, msg_iovec_t vec[], int veclen,
		   unsigned n, int exact)
{
  int i = 0;
  msg_payload_t *chunk;
  unsigned len = 0;
  char *buf;

  if (n == 0)
    return 0;

  if (veclen == 0)
    vec = NULL;

  for (chunk = msg->m_chunk; chunk; chunk = MSG_CHUNK_NEXT(chunk)) {
    buf = MSG_CHUNK_BUFFER(chunk);
    len = MSG_CHUNK_AVAIL(chunk);

    if (len == 0)
      continue;
    if (!buf)
      break;

    if (len > n)
      len = n;
    if (vec)
      vec[i].mv_base = buf, vec[i].mv_len = len;
    i++;
    if (len == n)
      return i;
    if (i == veclen)
      vec = NULL;
    n -= len;
  }

  if (!chunk && msg->m_chunk && msg_get_flags(msg, MSG_FLG_FRAGS)) {
    /*
     * If the m_chunk is the last fragment for this message,
     * receive rest of the data to the next message
     */
    if (msg->m_next == NULL)
      msg->m_next = msg_create(msg->m_class, msg->m_oflags);
    if (msg->m_next) {
      msg->m_next->m_maxsize = msg->m_maxsize;
      msg_addr_copy(msg->m_next, msg);
    }
    msg = msg->m_next;
    if (msg == NULL)
      return 0;
  }

  if (exact)
    buf = msg_buf_exact(msg, n + 1), len = n;
  else if (chunk && len > n && !msg_get_flags(msg, MSG_FLG_CHUNKING))
    buf = msg_buf_exact(msg, len + 1);
  else
    buf = msg_buf_alloc(msg, n + 1), len = msg_buf_size(msg);

  if (buf == NULL)
    return -1;

  if (vec)
    vec[i].mv_base = buf, vec[i].mv_len = n;

  if (chunk) {
    assert(chunk->pl_data == NULL); assert(chunk->pl_common->h_len == 0);

    chunk->pl_common->h_data = chunk->pl_data = buf;

    if (len < MSG_CHUNK_AVAIL(chunk)) {
      msg_header_t *h = (void*)chunk;
      h->sh_succ = msg_header_alloc(msg_home(msg), h->sh_class, 0);
      if (!h->sh_succ)
	return -1;
      h->sh_succ->sh_prev = &h->sh_succ;
      chunk->pl_next = (msg_payload_t *)h->sh_succ;
      chunk->pl_next->pl_len = chunk->pl_len - len;
      chunk->pl_len = len;
    }
    else if (len > MSG_CHUNK_AVAIL(chunk)) {
      len = MSG_CHUNK_AVAIL(chunk);
    }

    msg_buf_used(msg, len);
  }

  return i + 1;

#if 0
  if ((msg->m_ssize || msg->m_stream)
      /* && msg_get_flags(msg, MSG_FLG_BODY) */) {
    /* Streaming */
    msg_buffer_t *b, *b0;

    /* Calculate available size of current buffers */
    for (b = msg->m_stream, len = 0; b && n > len; b = b->b_next)
      len += b->b_avail - b->b_size;

    /* Allocate new buffers */
    if (n > len && msg_buf_external(msg, n, 0) < 0)
      return -1;

    for (b0 = msg->m_stream; b0; b0 = b0->b_next)
      if (b0->b_avail != b0->b_size)
	break;

    for (b = b0; b && n > 0; i++, b = b->b_next) {
      len = b->b_size - b->b_avail;
      len = n < len ? n : len;
      if (vec && i < veclen)
	vec[i].mv_base = b->b_data + b->b_avail, vec[i].mv_len = len;
      else
	vec = NULL;
      n -= len;
    }

    return i + 1;
  }
#endif
}


/** Obtain a buffer for receiving data */
int msg_recv_buffer(msg_t *msg, void **return_buffer)
{
  void *buffer;

  if (!msg)
    return -1;

  if (return_buffer == NULL)
    return_buffer = &buffer;

  if (msg->m_chunk) {
    msg_payload_t *pl;

    for (pl = msg->m_chunk; pl; pl = pl->pl_next) {
      unsigned n = MSG_CHUNK_AVAIL(pl);
      if (n) {
	*return_buffer = MSG_CHUNK_BUFFER(pl);
	return n;
      }
    }

    return 0;
  }

  if (msg_get_flags(msg, MSG_FLG_FRAGS)) {
    /* Message is complete */
    return 0;
  }
  else if ((*return_buffer = msg_buf_alloc(msg, 2))) {
    return msg_buf_size(msg) - 1;
  }
  else {
    return -1;
  }
}



/**Commit @a n bytes of buffers.
 *
 * @relates msg_s
 *
 * The function msg_recv_commit() is called after @a n bytes of data has
 * been received to the message buffers and the parser can extract the
 * received data.
 *
 * @param msg pointer to message object
 * @param n   number of bytes received
 * @param eos true if stream is complete
 *
 * @note The @a eos should be always true for message-based transports. It
 * should also be true when a stram oin stream-based transport ends, for
 * instance, when TCP FIN is received.
 *
 * @retval 0 when successful
 * @retval -1 upon an error.
 */
int msg_recv_commit(msg_t *msg, unsigned n, int eos)
{
  msg_payload_t *pl;

  if (eos)
    msg->m_buffer->mb_eos = 1;

  for (pl = msg->m_chunk; pl; pl = pl->pl_next) {
    unsigned len = MSG_CHUNK_AVAIL(pl);

    if (n <= len)
      len = n;

    pl->pl_common->h_len += len;

    n -= len;

    if (n == 0)
      return 0;
  }

  if (msg->m_chunk && msg->m_next)
    msg = msg->m_next;

  return msg_buf_commit(msg, n, eos);
}

/**Get a next message of the stream.
 *