diversion.c

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/* 
 * $Id: diversion.c 4657 2008-08-10 22:51:44Z henningw $
 *
 * Diversion Header Field Support
 *
 * Copyright (C) 2004 FhG Fokus
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * Kamailio 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <stdio.h>
#include <string.h>
#include "../../sr_module.h"
#include "../../error.h"
#include "../../dprint.h"
#include "../../mem/mem.h"
#include "../../data_lump.h"
#include "../../mod_fix.h"


MODULE_VERSION

#define DIVERSION_HF "Diversion"
#define DIVERSION_HF_LEN (sizeof(DIVERSION_HF) - 1)

#define DIVERSION_PREFIX     DIVERSION_HF ": <"
#define DIVERSION_PREFIX_LEN (sizeof(DIVERSION_PREFIX) - 1)

#define DIVERSION_SUFFIX     ">;reason="
#define DIVERSION_SUFFIX_LEN (sizeof(DIVERSION_SUFFIX) - 1)



str suffix = {"", 0};

int add_diversion(struct sip_msg* msg, char* r, char* s);

/*
 * Module initialization function prototype
 */
static int mod_init(void);


/*
 * Exported functions
 */
static cmd_export_t cmds[] = {
   {"add_diversion",    (cmd_function)add_diversion,    1, fixup_str_null,
      0, REQUEST_ROUTE|FAILURE_ROUTE|LOCAL_ROUTE},
   {0, 0, 0, 0, 0, 0}
};


/*
 * Exported parameters
 */
static param_export_t params[] = {
   {"suffix", STR_PARAM, &suffix.s},
   {0, 0, 0}
};


/*
 * Module interface
 */
struct module_exports exports = {
   "diversion", 
   DEFAULT_DLFLAGS, /* dlopen flags */
   cmds,       /* Exported functions */
   params,     /* Exported parameters */
   0,          /* exported statistics */
   0,          /* exported MI functions */
   0,          /* exported pseudo-variables */
   0,          /* extra processes */
   mod_init,   /* module initialization function */
   0,          /* response function */
   0,          /* destroy function */
   0           /* child initialization function */
};


static int mod_init(void)
{
   suffix.len = strlen(suffix.s);
   return 0;
}


static inline int add_diversion_helper(struct sip_msg* msg, str* s)
{
   char *ptr;

   static struct lump* anchor = 0;
   static unsigned int msg_id = 0;

   if (msg_id != msg->id) {
      msg_id = msg->id;
      anchor = 0;
   }
   
   if (!msg->diversion && parse_headers(msg, HDR_DIVERSION_F, 0) == -1) {
      LM_ERR("header parsing failed\n");
      return -1;
   }
   
   if (msg->diversion) {
           /* Insert just before the topmost Diversion header */
      ptr = msg->diversion->name.s;
   } else {
           /* Insert at the end */
      ptr = msg->unparsed;
   }

   if (!anchor) {
      anchor = anchor_lump(msg, ptr - msg->buf, 0, 0);
      if (!anchor) {
         LM_ERR("can't get anchor\n");
         return -2;
      }
   }
   
   if (!insert_new_lump_before(anchor, s->s, s->len, 0)) {
      LM_ERR("can't insert lump\n");
      return -3;
   }

   return 0;
}


int add_diversion(struct sip_msg* msg, char* r, char* s)
{
   str div_hf;
   char *at;
   str* uri;
   str* reason;

   reason = (str*)r;

   uri = &msg->first_line.u.request.uri;

   div_hf.len = DIVERSION_PREFIX_LEN + uri->len + DIVERSION_SUFFIX_LEN + reason->len + CRLF_LEN;
   div_hf.s = pkg_malloc(div_hf.len);
   if (!div_hf.s) {
      LM_ERR("no pkg memory left\n");
      return -1;
   }

   at = div_hf.s;
   memcpy(at, DIVERSION_PREFIX, DIVERSION_PREFIX_LEN);
   at += DIVERSION_PREFIX_LEN;

   memcpy(at, uri->s, uri->len);
   at += uri->len;

   memcpy(at, DIVERSION_SUFFIX, DIVERSION_SUFFIX_LEN);
   at += DIVERSION_SUFFIX_LEN;

   memcpy(at, reason->s, reason->len);
   at += reason->len;

   memcpy(at, CRLF, CRLF_LEN);

   if (add_diversion_helper(msg, &div_hf) < 0) {
      pkg_free(div_hf.s);
      return -1;
   }

   return 1;
}