Hu Chunming / sip_server

/*
  The oSIP library implements the Session Initiation Protocol (SIP -rfc3261-)
  Copyright (C) 2001-2020 Aymeric MOIZARD amoizard@antisip.com

  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <osipparser2/internal.h>

#include <osipparser2/osip_port.h>
#include <osipparser2/osip_parser.h>
#include "parser.h"

static void osip_util_replace_all_lws(char *sip_message);
static int osip_message_set__header(osip_message_t *sip, const char *hname, const char *hvalue);
static int msg_headers_parse(osip_message_t *sip, const char *start_of_header, const char **body);
static int msg_osip_body_parse(osip_message_t *sip, const char *start_of_buf, const char **next_body, size_t length);

static int __osip_message_startline_parsereq(osip_message_t *dest, const char *buf, const char **headers) {
  const char *p1;
  const char *p2;
  char *requesturi;
  int i;

  dest->sip_method = NULL;
  dest->status_code = 0;
  dest->reason_phrase = NULL;

  *headers = buf;

  /* The first token is the method name: */
  p2 = strchr(buf, ' ');

  if (p2 == NULL)
    return OSIP_SYNTAXERROR;

  if (*(p2 + 1) == '\0' || *(p2 + 2) == '\0')
    return OSIP_SYNTAXERROR;

  if (p2 - buf == 0) {
    OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "No space allowed here\n"));
    return OSIP_SYNTAXERROR;
  }

  dest->sip_method = (char *) osip_malloc(p2 - buf + 1);

  if (dest->sip_method == NULL)
    return OSIP_NOMEM;

  osip_strncpy(dest->sip_method, buf, p2 - buf);

  /* The second token is a sip-url or a uri: */
  p1 = strchr(p2 + 2, ' '); /* no space allowed inside sip-url */

  if (p1 == NULL) {
    OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "Uncompliant request-uri\n"));
    osip_free(dest->sip_method);
    dest->sip_method = NULL;
    return OSIP_SYNTAXERROR;
  }

  if (p1 - p2 < 2) {
    osip_free(dest->sip_method);
    dest->sip_method = NULL;
    return OSIP_SYNTAXERROR;
  }

  requesturi = (char *) osip_malloc(p1 - p2);

  if (requesturi == NULL) {
    osip_free(dest->sip_method);
    dest->sip_method = NULL;
    return OSIP_NOMEM;
  }

  osip_clrncpy(requesturi, p2 + 1, (p1 - p2 - 1));

  i = osip_uri_init(&(dest->req_uri));

  if (i != 0) {
    osip_free(requesturi);
    requesturi = NULL;
    osip_free(dest->sip_method);
    dest->sip_method = NULL;
    return OSIP_NOMEM;
  }

  i = osip_uri_parse(dest->req_uri, requesturi);
  osip_free(requesturi);

  if (i != 0) {
    osip_free(dest->sip_method);
    dest->sip_method = NULL;
    osip_uri_free(dest->req_uri);
    dest->req_uri = NULL;
    return OSIP_SYNTAXERROR;
  }

  /* find the the version and the beginning of headers */
  {
    const char *hp = p1;

    hp++; /* skip space */

    if (*hp == '\0' || *(hp + 1) == '\0' || *(hp + 2) == '\0' || *(hp + 3) == '\0' || *(hp + 4) == '\0' || *(hp + 5) == '\0' || *(hp + 6) == '\0') {
      OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "Uncomplete request line\n"));
      osip_free(dest->sip_method);
      dest->sip_method = NULL;
      osip_uri_free(dest->req_uri);
      dest->req_uri = NULL;
      return OSIP_SYNTAXERROR;
    }

    if (((hp[0] != 'S') && (hp[0] != 's')) || ((hp[1] != 'I') && (hp[1] != 'i')) || ((hp[2] != 'P') && (hp[2] != 'p')) || (hp[3] != '/')) {
      OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "No crlf found/No SIP/2.0 found\n"));
      osip_free(dest->sip_method);
      dest->sip_method = NULL;
      osip_uri_free(dest->req_uri);
      dest->req_uri = NULL;
      return OSIP_SYNTAXERROR;
    }

    hp = hp + 4; /* SIP/ */

    while ((*hp != '\r') && (*hp != '\n')) {
      if (*hp) {
        if ((*hp >= '0') && (*hp <= '9'))
          hp++;

        else if (*hp == '.')
          hp++;

        else {
          OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "incorrect sip version string\n"));
          osip_free(dest->sip_method);
          dest->sip_method = NULL;
          osip_uri_free(dest->req_uri);
          dest->req_uri = NULL;
          return OSIP_SYNTAXERROR;
        }

      } else {
        OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "No crlf found\n"));
        osip_free(dest->sip_method);
        dest->sip_method = NULL;
        osip_uri_free(dest->req_uri);
        dest->req_uri = NULL;
        return OSIP_SYNTAXERROR;
      }
    }

    if (hp - p1 < 2) {
      osip_free(dest->sip_method);
      dest->sip_method = NULL;
      osip_uri_free(dest->req_uri);
      dest->req_uri = NULL;
      return OSIP_SYNTAXERROR;
    }

    dest->sip_version = (char *) osip_malloc(hp - p1);

    if (dest->sip_version == NULL) {
      osip_free(dest->sip_method);
      dest->sip_method = NULL;
      osip_uri_free(dest->req_uri);
      dest->req_uri = NULL;
      return OSIP_NOMEM;
    }

    osip_strncpy(dest->sip_version, p1 + 1, (hp - p1 - 1));

    if (0 != osip_strcasecmp(dest->sip_version, "SIP/2.0")) {
      OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_WARNING, NULL, "Wrong version number\n"));
    }

    hp++;

    if ((*hp) && ('\r' == hp[-1]) && ('\n' == hp[0]))
      hp++;

    (*headers) = hp;
  }
  return OSIP_SUCCESS;
}

static int __osip_message_startline_parseresp(osip_message_t *dest, const char *buf, const char **headers) {
  const char *statuscode;
  const char *reasonphrase;

  dest->req_uri = NULL;
  dest->sip_method = NULL;

  *headers = buf;

  statuscode = strchr(buf, ' '); /* search for first SPACE */

  if (statuscode == NULL)
    return OSIP_SYNTAXERROR;

  if (statuscode - (*headers) < 7) /* must be at least "SIP" "/"  1*DIGIT "." 1*DIGIT */
    return OSIP_SYNTAXERROR;

  dest->sip_version = (char *) osip_malloc(statuscode - (*headers) + 1);

  if (dest->sip_version == NULL)
    return OSIP_NOMEM;

  osip_strncpy(dest->sip_version, *headers, statuscode - (*headers));

  reasonphrase = strchr(statuscode + 1, ' ');

  if (reasonphrase == NULL) {
    osip_free(dest->sip_version);
    dest->sip_version = NULL;
    return OSIP_SYNTAXERROR;
  }

  /* dest->status_code = (char *) osip_malloc (reasonphrase - statuscode); */
  /* osip_strncpy (dest->status_code, statuscode + 1, reasonphrase - statuscode - 1); */
  if (sscanf(statuscode + 1, "%d", &dest->status_code) != 1) {
    /* Non-numeric status code */
    return OSIP_SYNTAXERROR;
  }

  if (dest->status_code == 0)
    return OSIP_SYNTAXERROR;

  {
    const char *hp = reasonphrase;

    while ((*hp != '\r') && (*hp != '\n')) {
      if (*hp)
        hp++;

      else {
        OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "No crlf found\n"));
        return OSIP_SYNTAXERROR;
      }
    }

    dest->reason_phrase = (char *) osip_malloc(hp - reasonphrase);

    if (dest->reason_phrase == NULL) {
      osip_free(dest->sip_version);
      dest->sip_version = NULL;
      return OSIP_NOMEM;
    }

    osip_strncpy(dest->reason_phrase, reasonphrase + 1, hp - reasonphrase - 1);

    hp++;

    if ((*hp) && ('\r' == hp[-1]) && ('\n' == hp[0]))
      hp++;

    (*headers) = hp;
  }
  return OSIP_SUCCESS;
}

static int __osip_message_startline_parse(osip_message_t *dest, const char *buf, const char **headers) {
  if (0 == strncmp((const char *) buf, (const char *) "SIP/", 4))
    return __osip_message_startline_parseresp(dest, buf, headers);

  else
    return __osip_message_startline_parsereq(dest, buf, headers);
}

int __osip_find_next_occurence(const char *str, const char *buf, const char **index_of_str, const char *end_of_buf) {
  size_t slen;

  *index_of_str = NULL; /* AMD fix */

  if (str == NULL || buf == NULL)
    return OSIP_BADPARAMETER;

  slen = strlen(str);

  while (slen < (size_t)(end_of_buf - buf)) {
    if (!memcmp(str, buf, slen)) {
      *index_of_str = buf;
      return OSIP_SUCCESS;
    }

    ++buf;
  }

  return OSIP_SYNTAXERROR;
}

/* This method replace all LWS with SP located before the
   initial CRLFCRLF found or the end of the string.
*/
static void osip_util_replace_all_lws(char *sip_message) {
  /* const char *end_of_message; */
  char *tmp;

  if (sip_message == NULL)
    return;

  /* end_of_message = sip_message + strlen (sip_message); */

  tmp = sip_message;

  for (; tmp[0] != '\0'; tmp++) {
    if (('\0' == tmp[0]) || ('\0' == tmp[1]) || ('\0' == tmp[2]) || ('\0' == tmp[3]))
      return;

    if ((('\r' == tmp[0]) && ('\n' == tmp[1]) && ('\r' == tmp[2]) && ('\n' == tmp[3])) || (('\r' == tmp[0]) && ('\r' == tmp[1])) || (('\n' == tmp[0]) && ('\n' == tmp[1])))
      return; /* end of message */

    if ((('\r' == tmp[0]) && ('\n' == tmp[1]) && ((' ' == tmp[2]) || ('\t' == tmp[2]))) || (('\r' == tmp[0]) && ((' ' == tmp[1]) || ('\t' == tmp[1]))) || (('\n' == tmp[0]) && ((' ' == tmp[1]) || ('\t' == tmp[1])))) {
      /* replace line end and TAB symbols by SP */
      tmp[0] = ' ';
      tmp[1] = ' ';
      tmp = tmp + 2;

      /* replace all following TAB symbols */
      for (; ('\t' == tmp[0] || ' ' == tmp[0]);) {
        tmp[0] = ' ';
        tmp++;
      }

      if (tmp[0] == '\0') /* fixed Janv 13 2020: Heap-buffer-overflow with a final LWS without nothing after */
        return;
    }
  }
}

int __osip_find_next_crlf(const char *start_of_header, const char **end_of_header) {
  const char *soh = start_of_header;

  *end_of_header = NULL; /* AMD fix */

  while (('\r' != *soh) && ('\n' != *soh)) {
    if (*soh)
      soh++;

    else {
      OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "Final CRLF is missing\n"));
      return OSIP_SYNTAXERROR;
    }
  }

  if (('\r' == soh[0]) && ('\n' == soh[1]))
    /* case 1: CRLF is the separator
       case 2 or 3: CR or LF is the separator */
    soh = soh + 1;

  /* VERIFY if TMP is the end of header or LWS.            */
  /* LWS are extra SP, HT, CR and LF contained in headers. */
  if ((' ' == soh[1]) || ('\t' == soh[1])) {
    /* From now on, incoming message that potentially
       contains LWS must be processed with
       -> void osip_util_replace_all_lws(char *)
       This is because the parser methods does not
       support detection of LWS inside. */
    OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_BUG, NULL, "Message that contains LWS must be processed with osip_util_replace_all_lws(char *tmp) before being parsed.\n"));
    return -2;
  }

  *end_of_header = soh + 1;
  return OSIP_SUCCESS;
}

int __osip_find_next_crlfcrlf(const char *start_of_part, const char **end_of_part) {
  const char *start_of_line;
  const char *end_of_line;
  int i;

  start_of_line = start_of_part;

  for (;;) {
    i = __osip_find_next_crlf(start_of_line, &end_of_line);

    if (i == -2) {
    } else if (i != 0) { /* error case??? no end of mesage found */
      OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "Final CRLF is missing\n"));
      return i;
    }

    if ('\0' == end_of_line[0]) { /* error case??? no end of message found */
      OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "Final CRLF is missing\n"));
      return OSIP_SYNTAXERROR;

    } else if ('\r' == end_of_line[0]) {
      if ('\n' == end_of_line[1])
        end_of_line++;

      *end_of_part = end_of_line + 1;
      return OSIP_SUCCESS;

    } else if ('\n' == end_of_line[0]) {
      *end_of_part = end_of_line + 1;
      return OSIP_SUCCESS;
    }

    start_of_line = end_of_line;
  }
}

static int osip_message_set__header(osip_message_t *sip, const char *hname, const char *hvalue) {
  int my_index;

  if (hname == NULL)
    return OSIP_SYNTAXERROR;

  /* some headers are analysed completely      */
  /* this method is used for selective parsing */
  my_index = __osip_message_is_known_header(hname);

  if (my_index >= 0) { /* ok */
    int ret;

    ret = __osip_message_call_method(my_index, sip, hvalue);

    if (ret != 0)
      return ret;

    return OSIP_SUCCESS;
  }

  /* unknownheader */
  if (osip_message_set_header(sip, hname, hvalue) != 0) {
    OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_WARNING, NULL, "Could not set unknown header\n"));
    return OSIP_SUCCESS;
  }

  return OSIP_SUCCESS;
}

int osip_message_set_multiple_header(osip_message_t *sip, char *hname, char *hvalue) {
  int i;
  char *ptr, *p;       /* current location of the search */
  char *comma;         /* This is the separator we are elooking for */
  char *beg;           /* beg of a header */
  char *end;           /* end of a header */
  int inquotes, inuri; /* state for inside/outside of double-qoutes or URI */

  /* Find header based upon lowercase comparison */
  osip_tolower(hname);

  if (hvalue == NULL) {
    i = osip_message_set__header(sip, hname, hvalue);

    if (i != 0)
      return i;

    return OSIP_SUCCESS;
  }

  ptr = hvalue;
  comma = strchr(ptr, ',');

  /* if there is a COMMA, we check if the header is allowed on multiple line from an internal
     list: those headers are defined in rfc to support the following format.
     header  =  "header-name" HCOLON header-value *(COMMA header-value)
     We cannot guess for any other headers and thus, we will handle other headers as one header.
   */
  if (comma == NULL || __osip_message_is_header_comma_separated(hname) != OSIP_SUCCESS) {
    i = osip_message_set__header(sip, hname, hvalue);

    if (i != 0)
      return i;

    return OSIP_SUCCESS;
  }

  beg = hvalue;
  inquotes = 0;
  inuri = 0;

  /* Seach for a comma that is not within quotes or a URI */
  for (;; ptr++) {
    switch (*ptr) {
    case '"':

      /* Check that the '"' is not escaped */
      for (i = 0, p = ptr - 1; p >= beg && *p == '\\'; p--, i++)
        ;

      if (i % 2 == 0)
        inquotes = !inquotes; /* the '"' was not escaped */

      break;

    case '<':
      if (!inquotes) {
        if (!inuri) {
          if ((osip_strncasecmp(ptr + 1, "sip:", 4) == 0 || osip_strncasecmp(ptr + 1, "sips:", 5) == 0 || osip_strncasecmp(ptr + 1, "http:", 5) == 0 || osip_strncasecmp(ptr + 1, "https:", 6) == 0 || osip_strncasecmp(ptr + 1, "tel:", 4) == 0) &&
              strchr(ptr, '>'))
            inuri = 1;
        }

        /*
           else {
           if we found such sequence: "<sip:" "<sip:" ">"
           It might be a valid header containing data and not URIs.
           Thus, we ignore inuri
           }
         */
      }

      break;

    case '>':
      if (!inquotes) {
        if (inuri)
          inuri = 0;
      }

      break;

    case '\0':
      /* we discard any validation we tried: no valid uri detected */
      inquotes = 0;
      inuri = 0;

    // (keep next comment to avoid fall through warning)
    // fall through
    case ',':
      if (!inquotes && !inuri) {
        char *avalue;

        if (beg[0] == '\0')
          return OSIP_SUCCESS; /* empty header */

        end = ptr;

        if (end - beg + 1 < 2) {
          beg = end + 1;
          break; /* skip empty header */
        }

        avalue = (char *) osip_malloc(end - beg + 1);

        if (avalue == NULL)
          return OSIP_NOMEM;

        osip_clrncpy(avalue, beg, end - beg);
        /* really store the header in the sip structure */
        i = osip_message_set__header(sip, hname, avalue);
        osip_free(avalue);

        if (i != 0)
          return i;

        beg = end + 1;
      }

      if (*ptr == '\0')
        return OSIP_SUCCESS;

      break;

    default:
      break;
    }
  }
}

/* set all headers */
static int msg_headers_parse(osip_message_t *sip, const char *start_of_header, const char **body) {
  const char *colon_index; /* index of ':' */
  char *hname;
  char *hvalue;
  const char *end_of_header;
  int i;

  for (;;) {
    if (start_of_header[0] == '\0') { /* final CRLF is missing */
      OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_INFO1, NULL, "SIP message does not end with CRLFCRLF\n"));
      return OSIP_SUCCESS;
    }

    i = __osip_find_next_crlf(start_of_header, &end_of_header);

    if (i == -2) {
    } else if (i != 0) {
      OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "End of header Not found\n"));
      return i; /* this is an error case!     */
    }

    /* the list of headers MUST always end with  */
    /* CRLFCRLF (also CRCR and LFLF are allowed) */
    if ((start_of_header[0] == '\r') || (start_of_header[0] == '\n')) {
      *body = start_of_header;
      return OSIP_SUCCESS; /* end of header found        */
    }

    /* find the header name */
    colon_index = strchr(start_of_header, ':');

    if (colon_index == NULL) {
      OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "End of header Not found\n"));
      return OSIP_SYNTAXERROR; /* this is also an error case */
    }

    if (colon_index - start_of_header + 1 < 2)
      return OSIP_SYNTAXERROR;

    if (end_of_header <= colon_index) {
      OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "Malformed message\n"));
      return OSIP_SYNTAXERROR;
    }

    hname = (char *) osip_malloc(colon_index - start_of_header + 1);

    if (hname == NULL)
      return OSIP_NOMEM;

    osip_clrncpy(hname, start_of_header, colon_index - start_of_header);

    {
      const char *end;

      /* END of header is (end_of_header-2) if header separation is CRLF */
      /* END of header is (end_of_header-1) if header separation is CR or LF */
      if ((end_of_header[-2] == '\r') || (end_of_header[-2] == '\n'))
        end = end_of_header - 2;

      else
        end = end_of_header - 1;

      if ((end) -colon_index < 2)
        hvalue = NULL; /* some headers (subject) can be empty */
      else {
        hvalue = (char *) osip_malloc((end) -colon_index + 1);

        if (hvalue == NULL) {
          osip_free(hname);
          return OSIP_NOMEM;
        }

        osip_clrncpy(hvalue, colon_index + 1, (end) -colon_index - 1);
      }
    }

    /* hvalue MAY contains multiple value. In this case, they   */
    /* are separated by commas. But, a comma may be part of a   */
    /* quoted-string ("here, and there" is an example where the */
    /* comma is not a separator!) */
    i = osip_message_set_multiple_header(sip, hname, hvalue);

    osip_free(hname);

    if (hvalue != NULL)
      osip_free(hvalue);

    if (i != 0) {
      OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "End of header Not found\n"));
      return OSIP_SYNTAXERROR;
    }

    /* continue on the next header */
    start_of_header = end_of_header;
  }

  /* Unreachable code
   OSIP_TRACE (osip_trace
          (__FILE__, __LINE__, OSIP_BUG, NULL,
           "This code cannot be reached\n")); */
  return OSIP_SYNTAXERROR;
}

static int msg_osip_body_parse(osip_message_t *sip, const char *start_of_buf, const char **next_body, size_t length) {
  const char *start_of_body;
  const char *end_of_body;
  const char *end_of_buf;
  char *tmp;
  int i;

  char *sep_boundary;
  size_t len_sep_boundary;
  osip_generic_param_t *ct_param;

  if (sip->content_type == NULL || sip->content_type->type == NULL || sip->content_type->subtype == NULL)
    return OSIP_SUCCESS; /* no body is attached */

  if (0 != osip_strcasecmp(sip->content_type->type, "multipart")) {
    size_t osip_body_len;

    if (start_of_buf[0] == '\0')
      return OSIP_SYNTAXERROR; /* final CRLF is missing */

    /* get rid of the first CRLF */
    if ('\r' == start_of_buf[0]) {
      if ('\n' == start_of_buf[1])
        start_of_body = start_of_buf + 2;

      else
        start_of_body = start_of_buf + 1;

    } else if ('\n' == start_of_buf[0])
      start_of_body = start_of_buf + 1;

    else
      return OSIP_SYNTAXERROR; /* message does not end with CRLFCRLF, CRCR or LFLF */

    /* update length (without CRLFCRLF */
    length = length - (start_of_body - start_of_buf); /* fixed 24 08 2004 */

    if (length <= 0)
      return OSIP_SYNTAXERROR;

    if (sip->content_length != NULL)
      osip_body_len = osip_atoi(sip->content_length->value);

    else {
      /* if content_length does not exist, set it. */
      char tmp[16];

      osip_body_len = length;
      sprintf(tmp, "%i", (int) osip_body_len);
      i = osip_message_set_content_length(sip, tmp);

      if (i != 0)
        return i;
    }

    if (length < osip_body_len) {
      OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "Message was not receieved enterely. length=%i osip_body_len=%i\n", (int) length, (int) osip_body_len));
      return OSIP_SYNTAXERROR;
    }

    end_of_body = start_of_body + osip_body_len;
    tmp = osip_malloc(end_of_body - start_of_body + 2);

    if (tmp == NULL)
      return OSIP_NOMEM;

    memcpy(tmp, start_of_body, end_of_body - start_of_body);
    tmp[end_of_body - start_of_body] = '\0';

    i = osip_message_set_body(sip, tmp, end_of_body - start_of_body);
    osip_free(tmp);

    if (i != 0)
      return i;

    return OSIP_SUCCESS;
  }

  /* find the boundary */
  i = osip_generic_param_get_byname(&sip->content_type->gen_params, "boundary", &ct_param);

  if (i != 0)
    return i;

  if (ct_param == NULL)
    return OSIP_SYNTAXERROR;

  if (ct_param->gvalue == NULL)
    return OSIP_SYNTAXERROR; /* No boundary but multiple headers??? */

  {
    const char *boundary_prefix = "\n--";

    size_t len = strlen(ct_param->gvalue);

    sep_boundary = (char *) osip_malloc(len + 4);

    if (sep_boundary == NULL)
      return OSIP_NOMEM;

    strcpy(sep_boundary, boundary_prefix);

    if (ct_param->gvalue[0] == '"' && ct_param->gvalue[len - 1] == '"')
      strncat(sep_boundary, ct_param->gvalue + 1, len - 2);

    else
      strncat(sep_boundary, ct_param->gvalue, len);
  }

  len_sep_boundary = strlen(sep_boundary);

  *next_body = NULL;
  start_of_body = start_of_buf;

  end_of_buf = start_of_buf + length;

  for (;;) {
    size_t body_len = 0;

    i = __osip_find_next_occurence(sep_boundary, start_of_body, &start_of_body, end_of_buf);

    if (i != 0) {
      osip_free(sep_boundary);
      return i;
    }

    i = __osip_find_next_occurence(sep_boundary, start_of_body + len_sep_boundary, &end_of_body, end_of_buf);

    if (i != 0) {
      osip_free(sep_boundary);
      return i;
    }

    /* this is the real beginning of body */
    start_of_body = start_of_body + len_sep_boundary + 1;

    if ('\n' == start_of_body[0] || '\r' == start_of_body[0])
      start_of_body++;

    /* if message body is empty or contains a single CR/LF */
    if (end_of_body <= start_of_body) {
      osip_free(sep_boundary);
      return OSIP_SYNTAXERROR;
    }

    body_len = end_of_body - start_of_body;

    /* Skip CR before end boundary. */
    if (*(end_of_body - 1) == '\r')
      body_len--;

    tmp = osip_malloc(body_len + 2);

    if (tmp == NULL) {
      osip_free(sep_boundary);
      return OSIP_NOMEM;
    }

    memcpy(tmp, start_of_body, body_len);
    tmp[body_len] = '\0';

    i = osip_message_set_body_mime(sip, tmp, body_len);
    osip_free(tmp);

    if (i != 0) {
      osip_free(sep_boundary);
      return i;
    }

    if (strncmp(end_of_body + len_sep_boundary, "--", 2) == 0) { /* end of all bodies */
      *next_body = end_of_body;
      osip_free(sep_boundary);
      return OSIP_SUCCESS;
    }

    /* continue on the next body */
    start_of_body = end_of_body;
  }

  /* Unreachable code */
  /* osip_free (sep_boundary); */
  return OSIP_SYNTAXERROR;
}

/* osip_message_t *sip is filled while analysing buf */
static int _osip_message_parse(osip_message_t *sip, const char *buf, size_t length, int sipfrag) {
  int i;
  const char *next_header_index;
  char *tmp;
  char *beg;

  tmp = osip_malloc(length + 2);

  if (tmp == NULL) {
    OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "Could not allocate memory.\n"));
    return OSIP_NOMEM;
  }

  beg = tmp;
  memcpy(tmp, buf, length); /* may contain binary data */
  tmp[length] = '\0';
  /* skip initial \r\n */
  tmp += strspn(tmp, "\r\n");
  osip_util_replace_all_lws(tmp);
  /* parse request or status line */
  i = __osip_message_startline_parse(sip, tmp, &next_header_index);

  if (i != 0 && !sipfrag) {
    OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "Could not parse start line of message.\n"));
    osip_free(beg);
    return i;
  }

  tmp = (char *) next_header_index;

  /* parse headers */
  i = msg_headers_parse(sip, tmp, &next_header_index);

  if (i != 0) {
    OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "error in msg_headers_parse()\n"));
    osip_free(beg);
    return i;
  }

  tmp = (char *) next_header_index;

  if (sip->content_length != NULL && sip->content_length->value == NULL) {
    /* empty content_length header */
    osip_content_length_free(sip->content_length);
    sip->content_length = NULL;
  }

  if (sip->content_length != NULL && sip->content_length->value != NULL && atoi(sip->content_length->value) > 0) {
    /* body exist */
  } else if (sip->content_length == NULL && '\r' == next_header_index[0] && '\n' == next_header_index[1] && length - (tmp - beg) - (2) > 0) {
    /* body exist */
  } else if (sip->content_length == NULL && '\n' == next_header_index[0] && length - (tmp - beg) - (1) > 0) {
    /* body exist */
  } else {
    if (sip->content_length == NULL)
      osip_message_set_content_length(sip, "0");

    osip_free(beg);
    return OSIP_SUCCESS; /* no body found */
  }

  i = msg_osip_body_parse(sip, tmp, &next_header_index, length - (tmp - beg));
  osip_free(beg);

  if (i != 0) {
    OSIP_TRACE(osip_trace(__FILE__, __LINE__, OSIP_ERROR, NULL, "error in msg_osip_body_parse()\n"));
    return i;
  }

  /* this is mandatory in the oSIP stack */
  if (sip->content_length == NULL)
    osip_message_set_content_length(sip, "0");

  return OSIP_SUCCESS;
}

int osip_message_parse(osip_message_t *sip, const char *buf, size_t length) {
  return _osip_message_parse(sip, buf, length, 0);
}

int osip_message_parse_sipfrag(osip_message_t *sip, const char *buf, size_t length) {
  return _osip_message_parse(sip, buf, length, 1);
}

/* This method just add a received parameter in the Via
   as requested by rfc3261 */
int osip_message_fix_last_via_header(osip_message_t *request, const char *ip_addr, int port) {
  osip_generic_param_t *rport;
  osip_via_t *via;

  /* get Top most Via header: */
  if (request == NULL)
    return OSIP_BADPARAMETER;

  if (MSG_IS_RESPONSE(request))
    return OSIP_SUCCESS; /* Don't fix Via header */

  via = osip_list_get(&request->vias, 0);

  if (via == NULL || via->host == NULL)
    /* Hey, we could build it? */
    return OSIP_BADPARAMETER;

  osip_via_param_get_byname(via, "rport", &rport);

  if (rport != NULL) {
    if (rport->gvalue == NULL) {
      rport->gvalue = (char *) osip_malloc(9);

      if (rport->gvalue == NULL)
        return OSIP_NOMEM;

#if !defined __PALMOS__ && (defined WIN32 || defined _WIN32_WCE)
      _snprintf(rport->gvalue, 8, "%i", port);
#else
      snprintf(rport->gvalue, 8, "%i", port);
#endif
    } /* else bug? */
  }

  /* only add the received parameter if the 'sent-by' value does not contains
     this ip address */
  if (0 == strcmp(via->host, ip_addr)) /* don't need the received parameter */
    return OSIP_SUCCESS;

  osip_via_set_received(via, osip_strdup(ip_addr));
  return OSIP_SUCCESS;
}

const char *osip_message_get_reason(int replycode) {
  struct code_to_reason {
    int code;
    const char *reason;
  };

  static const struct code_to_reason reasons1xx[] = {
      {100, "Trying"}, {180, "Ringing"}, {181, "Call Is Being Forwarded"}, {182, "Queued"}, {183, "Session Progress"}, {199, "Early Dialog Terminated"},
  };
  static const struct code_to_reason reasons2xx[] = {
      {200, "OK"},
      {202, "Accepted"},
      {204, "No Notification"},
  };
  static const struct code_to_reason reasons3xx[] = {
      {300, "Multiple Choices"}, {301, "Moved Permanently"}, {302, "Moved Temporarily"}, {305, "Use Proxy"}, {380, "Alternative Service"},
  };
  static const struct code_to_reason reasons4xx[] = {
      {400, "Bad Request"},
      {401, "Unauthorized"},
      {402, "Payment Required"},
      {403, "Forbidden"},
      {404, "Not Found"},
      {405, "Method Not Allowed"},
      {406, "Not Acceptable"},
      {407, "Proxy Authentication Required"},
      {408, "Request Timeout"},
      {409, "Conflict"},
      {410, "Gone"},
      {411, "Length Required"},
      {412, "Conditional Request Failed"},
      {413, "Request Entity Too Large"},
      {414, "Request-URI Too Long"},
      {415, "Unsupported Media Type"},
      {416, "Unsupported URI Scheme"},
      {417, "Unknown Resource-Priority"},
      {420, "Bad Extension"},
      {421, "Extension Required"},
      {422, "Session Interval Too Small"},
      {423, "Interval Too Brief"},
      {424, "Bad Location Information"},
      {428, "Use Identity Header"},
      {429, "Provide Referrer Identity"},
      {430, "Flow Failed"},
      {433, "Anonymity Disallowed"},
      {436, "Bad Identity Info"},
      {437, "Unsupported Credential"},
      {438, "Invalid Identity Header"},
      {439, "First Hop Lacks Outbound Support"},
      {440, "Max-Breadth Exceeded"},
      {469, "Bad Info Package"},
      {470, "Consent Needed"},
      {480, "Temporarily Unavailable"},
      {481, "Call/Transaction Does Not Exist"},
      {482, "Loop Detected"},
      {483, "Too Many Hops"},
      {484, "Address Incomplete"},
      {485, "Ambiguous"},
      {486, "Busy Here"},
      {487, "Request Terminated"},
      {488, "Not Acceptable Here"},
      {489, "Bad Event"},
      {491, "Request Pending"},
      {493, "Undecipherable"},
      {494, "Security Agreement Required"},
  };
  static const struct code_to_reason reasons5xx[] = {
      {500, "Server Internal Error"}, {501, "Not Implemented"}, {502, "Bad Gateway"}, {503, "Service Unavailable"}, {504, "Server Time-out"}, {505, "Version Not Supported"}, {513, "Message Too Large"}, {580, "Precondition Failure"},
  };
  static const struct code_to_reason reasons6xx[] = {{600, "Busy Everywhere"}, {603, "Decline"}, {604, "Does Not Exist Anywhere"}, {606, "Not Acceptable"}, {607, "Unwanted"}, {687, "Dialog Terminated"}};
  const struct code_to_reason *reasons;
  int len, i;

  switch (replycode / 100) {
  case 1:
    reasons = reasons1xx;
    len = sizeof(reasons1xx) / sizeof(*reasons);
    break;

  case 2:
    reasons = reasons2xx;
    len = sizeof(reasons2xx) / sizeof(*reasons);
    break;

  case 3:
    reasons = reasons3xx;
    len = sizeof(reasons3xx) / sizeof(*reasons);
    break;

  case 4:
    reasons = reasons4xx;
    len = sizeof(reasons4xx) / sizeof(*reasons);
    break;

  case 5:
    reasons = reasons5xx;
    len = sizeof(reasons5xx) / sizeof(*reasons);
    break;

  case 6:
    reasons = reasons6xx;
    len = sizeof(reasons6xx) / sizeof(*reasons);
    break;

  default:
    return NULL;
  }

  for (i = 0; i < len; i++)
    if (reasons[i].code == replycode)
      return reasons[i].reason;

  /* Not found. */
  return NULL;
}