filter.c

用于linux环境下的SIP服务器

/*
  The filter plugin is a GPL plugin for partysip.
  Copyright (C) 2002,2003  WellX Telecom   - <[e-mail]>
  Copyright (C) 2002,2003  Aymeric MOIZARD - <[e-mail]>
  
  The filter plugin 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.
  
  The filter plugin 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 Foobar; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <partysip/partysip.h>
#include <partysip/psp_utils.h>

#include <ppl/ppl_dns.h>

#include "filter.h"

filter_ctx_t *filter_context = NULL;

extern psp_plugin_t PPL_DECLARE_DATA filter_plugin;
extern char filter_name_config[50];

/*
  This plugin can be configured to:
  * 
  * mandate record-routing to stay on the path for the duration of the call.
       ("proxy-mode")

  */

/*
  Configuration sample:.
  
  <filter>

  mode          statefull
  # record-route  on

  # tel url definitions 
  forward    ^tel:07([0-9]+)|sip:[e-mail];user=phone
  forward    ^tel:0[89]([0-9]+)|sip:713@192.168.1.83;user=phone
  forward    ^tel:(1[01])([0-9]+)|sip:[e-mail]
  forward    ^tel:12([0-9]+)|sip:[e-mail]
  forward    ^tel:13([0-9]+)|sip:g3.france.com
  forward    ^tel:([0-9]+)|sip:[e-mail]

  </filter>
*/

#define INTERNAL_SCOPE      0x1000
#define EXTERNAL_SCOPE      0x0100
#define REDIRECT_MODE      0x0010
#define R_ROUTE_MODE       0x0001

#define ISSET_INTERNAL_FILTERSCOPE(flag) ((~flag|~INTERNAL_SCOPE)==~INTERNAL_SCOPE)
#define SET_INTERNAL_FILTERSCOPE(flag)   (flag=flag|INTERNAL_SCOPE)

#define ISSET_EXTERNAL_FILTERSCOPE(flag) ((~flag|~EXTERNAL_SCOPE)==~EXTERNAL_SCOPE)
#define SET_EXTERNAL_FILTERSCOPE(flag)   (flag=flag|EXTERNAL_SCOPE)

#define ISSET_REDIRECT_MODE(flag)    ((~flag|~REDIRECT_MODE)==~REDIRECT_MODE)
#define SET_REDIRECT_MODE(flag)      (flag=flag|REDIRECT_MODE)

#define ISSET_R_ROUTE_MODE(flag)     ((~flag|~R_ROUTE_MODE)==~R_ROUTE_MODE)
#define SET_R_ROUTE_MODE(flag)       (flag=flag|R_ROUTE_MODE)

#if !defined(WIN32) || defined(TRE)
static int filter_load_forward_config()
{
  int i;
  config_element_t *elem;
  config_element_t *next_elem;
  char *arg1;
  
  elem = psp_config_get_sub_element("forward", filter_name_config, NULL);
  
  while (elem!=NULL)
    {
      tel_rule_t *tel_rule;
      /*
	forward    ^tel:07([0-9]+)|sip:[e-mail];user=phone
	forward    ^tel:0[89]([0-9]+)|sip:713@192.168.1.83;user=phone
	forward    ^tel:(1[01])([0-9]+)|sip:[e-mail]
      */

      arg1 = strchr(elem->value, '|'); /* find beginning of prefix */
      if (arg1==NULL) return -1;
      arg1=arg1+1;

      /* only 100 length is allowed */
      if (arg1-elem->value-1>100) return -1;
      if (strlen(arg1)>100) return -1;

      tel_rule = (tel_rule_t*) osip_malloc(sizeof(tel_rule_t));
      memset(tel_rule, 0, sizeof(tel_rule_t));
      tel_rule->next   = NULL;
      tel_rule->parent = NULL;
      osip_strncpy(tel_rule->prefix, elem->value, arg1-elem->value-1);
      osip_strncpy(tel_rule->dnsresult, arg1, strlen(arg1));
      /* pre-compile the regex */
      i = regcomp(&tel_rule->cprefix, tel_rule->prefix,
		  REG_EXTENDED|REG_ICASE);
      if (i!=0)
	{
	  OSIP_TRACE(osip_trace(__FILE__,__LINE__,OSIP_ERROR,NULL,
				"filter plugin: Error in regex pattern: %s!\n",
				tel_rule->prefix));
	  osip_free(tel_rule);
	  return -1;
	}

      ADD_ELEMENT(filter_context->tel_rules, tel_rule);

      next_elem = elem;
      elem = psp_config_get_sub_element("forward", filter_name_config, next_elem);
    }
  return 0;
}
#endif

int
filter_ctx_init()
{
  config_element_t *elem;
  int i;

#if defined(WIN32) && !defined(TRE)
  OSIP_TRACE(osip_trace(__FILE__,__LINE__,OSIP_INFO4,NULL,
			"filter plugin: NOT IMPLEMENTED ON WIN32!\n"));
  return 0;
#else

  filter_context = (filter_ctx_t*)osip_malloc(sizeof(filter_ctx_t));
  if (filter_context==NULL) return -1;
  
  filter_context->tel_rules = NULL;

  filter_context->flag = 0;
  elem = psp_config_get_sub_element("mode", filter_name_config, NULL);
  if (elem==NULL||elem->value==NULL)
    { }
  else if (0==strcmp(elem->value, "redirect"))
    SET_REDIRECT_MODE(filter_context->flag);
  else if (0==strcmp(elem->value, "statefull"))
    { }
  else
    goto lsci_error1; /* error, bad option */

  elem = psp_config_get_sub_element("filter_scope", filter_name_config, NULL);
  if (elem==NULL||elem->value==NULL)
    {
      SET_INTERNAL_FILTERSCOPE(filter_context->flag);
      SET_EXTERNAL_FILTERSCOPE(filter_context->flag);
    }
  else if (0==strcmp(elem->value, "internal"))
    SET_INTERNAL_FILTERSCOPE(filter_context->flag);
  else if (0==strcmp(elem->value, "external"))
    SET_EXTERNAL_FILTERSCOPE(filter_context->flag);
  else if (0==strcmp(elem->value, "both"))
    {
      SET_INTERNAL_FILTERSCOPE(filter_context->flag);
      SET_EXTERNAL_FILTERSCOPE(filter_context->flag);
    }
  else
    goto lsci_error1; /* error, bad option */

  elem = psp_config_get_sub_element("record-route", filter_name_config, NULL);
  if (elem==NULL||elem->value==NULL)
    { }
  else if (0==strcmp(elem->value, "off"))
    { }
  else if (0==strcmp(elem->value, "on"))
    SET_R_ROUTE_MODE(filter_context->flag);
  else
    goto lsci_error1; /* error, bad option */  

  /* load the configuration behavior for INVITE */
  i = filter_load_forward_config();
  if (i!=0) goto lsci_error2;
  
  if (ISSET_R_ROUTE_MODE(filter_context->flag))
    {
      OSIP_TRACE(osip_trace(__FILE__,__LINE__,OSIP_INFO1,NULL,
		  "filter plugin: configured to do record-routing!\n"));
    }

  if (ISSET_REDIRECT_MODE(filter_context->flag))
    {
      OSIP_TRACE(osip_trace(__FILE__,__LINE__,OSIP_INFO1,NULL,
		  "filter plugin: configured in redirect mode!\n"));
    }

  if (ISSET_INTERNAL_FILTERSCOPE(filter_context->flag))
    {
      OSIP_TRACE(osip_trace(__FILE__,__LINE__,OSIP_INFO1,NULL,
		  "filter plugin: configured to process url for local domain!\n"));
    }

  if (ISSET_EXTERNAL_FILTERSCOPE(filter_context->flag))
    {
      OSIP_TRACE(osip_trace(__FILE__,__LINE__,OSIP_INFO1,NULL,
		  "filter plugin: configured to process url for non local domain!\n"));
    }

  return 0;

 lsci_error2:
 lsci_error1:
  osip_free(filter_context);
  filter_context = NULL;
  return -1;
#endif
}

void
filter_ctx_free()
{
  tel_rule_t *tel_rule;
  if (filter_context==NULL) return;

#if !defined(WIN32) || defined(TRE)
  for (tel_rule = filter_context->tel_rules;
       tel_rule!=NULL;
       tel_rule=filter_context->tel_rules)
  {
    REMOVE_ELEMENT(filter_context->tel_rules, tel_rule);
    regfree(&tel_rule->cprefix);
    osip_free(tel_rule);
  }

  osip_free(filter_context);
  filter_context = NULL;
#endif
}

#if !defined(WIN32) || defined(TRE)

static int
filter_match_rule(tel_rule_t *tel_rule, osip_message_t *request,
		    char *match1, char *match2)
{
  osip_uri_t *req_uri = request->req_uri;
  char *url;
  int i;
  regmatch_t pmatch[3];
  if (tel_rule->prefix=='\0') return 0; /* always match */

  if (req_uri==NULL)
    return -1;

  osip_uri_to_str_canonical(req_uri, &url);
  if (url==NULL)
    {
      OSIP_TRACE(osip_trace(__FILE__,__LINE__,OSIP_ERROR,NULL,
			    "filter plugin: Bad sip url in SIP request.\n",
			    tel_rule->prefix));
      return -1;
    }

  /* match one sip url */
  i = regexec(&tel_rule->cprefix, url, tel_rule->cprefix.re_nsub+1, pmatch, 0);
  if (i!=0)
    {
      if (i!=REG_NOMATCH)
	{
	  char error_buf[512];
	  regerror(i, &tel_rule->cprefix, error_buf, 512);
	  OSIP_TRACE(osip_trace(__FILE__,__LINE__,OSIP_ERROR,NULL,
				"filter plugin: regexec failed(%i) for %s!\n",
				i, error_buf));
	}
      else
	{
	  OSIP_TRACE(osip_trace(__FILE__,__LINE__,OSIP_INFO4,NULL,
				"filter plugin: No match for %s!\n", url));
	}
      osip_free(url);
      return -1;
    }
  
#ifdef FILTER_TEST
    fprintf(stdout, "tel_rule->cprefix.re_nsub+1: %i\n",
	    tel_rule->cprefix.re_nsub+1);
#endif

  for (i=0;pmatch[i].rm_so!=-1 && tel_rule->cprefix.re_nsub+1 != i ;i++)
    {
#ifdef FILTER_TEST
      fprintf(stdout, "result of regexec: %i %i\n",
	      pmatch[i].rm_so, pmatch[i].rm_eo);
      fprintf(stdout, "pmatch[i].rm_so: %s\n", url+pmatch[i].rm_so);