res_pjsip_diversion.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * Kevin Harwell <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*** MODULEINFO
   <depend>pjproject</depend>
   <depend>res_pjsip</depend>
   <depend>res_pjsip_session</depend>
   <support_level>core</support_level>
 ***/

#include "asterisk.h"

#include <pjsip.h>
#include <pjsip_ua.h>

#include "asterisk/res_pjsip.h"
#include "asterisk/res_pjsip_session.h"
#include "asterisk/callerid.h"
#include "asterisk/channel.h"
#include "asterisk/module.h"
#include "asterisk/strings.h"

static const pj_str_t diversion_name = { "Diversion", 9 };
static const pj_str_t history_info_name = { "History-Info", 12 };
static pj_str_t HISTINFO_SUPPORTED_NAME = { "histinfo", 8 };

/*!
 * \internal
 * \brief Determine if the given string is a SIP token.
 * \since 13.8.0
 *
 * \param str String to determine if is a SIP token.
 *
 * \note A token is defined by RFC3261 Section 25.1
 *
 * \return Non-zero if the string is a SIP token.
 */
static int sip_is_token(const char *str)
{
   int is_token;

   if (ast_strlen_zero(str)) {
      /* An empty string is not a token. */
      return 0;
   }

   is_token = 1;
   do {
      if (!isalnum(*str)
         && !strchr("-.!%*_+`'~", *str)) {
         /* The character is not allowed in a token. */
         is_token = 0;
         break;
      }
   } while (*++str);

   return is_token;
}

/*! \brief Diversion header reasons
 *
 * The core defines a bunch of constants used to define
 * redirecting reasons. This provides a translation table
 * between those and the strings which may be present in
 * a SIP Diversion header
 */
static const struct reasons {
   enum AST_REDIRECTING_REASON code;
   const char *text;
   const unsigned int cause;
} reason_table[] = {
   { AST_REDIRECTING_REASON_UNKNOWN, "unknown", 404 },
   { AST_REDIRECTING_REASON_USER_BUSY, "user-busy", 486 },
   { AST_REDIRECTING_REASON_NO_ANSWER, "no-answer", 408 },
   { AST_REDIRECTING_REASON_UNAVAILABLE, "unavailable", 503 },
   { AST_REDIRECTING_REASON_UNCONDITIONAL, "unconditional", 302 },
   { AST_REDIRECTING_REASON_TIME_OF_DAY, "time-of-day", 404 },
   { AST_REDIRECTING_REASON_DO_NOT_DISTURB, "do-not-disturb", 404 },
   { AST_REDIRECTING_REASON_DEFLECTION, "deflection", 480 },
   { AST_REDIRECTING_REASON_FOLLOW_ME, "follow-me", 404 },
   { AST_REDIRECTING_REASON_OUT_OF_ORDER, "out-of-service", 404 },
   { AST_REDIRECTING_REASON_AWAY, "away", 404 },
   { AST_REDIRECTING_REASON_CALL_FWD_DTE, "cf_dte", 404 },     /* Non-standard */
   { AST_REDIRECTING_REASON_SEND_TO_VM, "send_to_vm", 404 },   /* Non-standard */
};

static enum AST_REDIRECTING_REASON cause_to_reason(const unsigned long cause) {
   switch(cause) {
      case 302:
         return AST_REDIRECTING_REASON_UNCONDITIONAL;
      case 486:
         return AST_REDIRECTING_REASON_USER_BUSY;
      case 408:
         return AST_REDIRECTING_REASON_NO_ANSWER;
      case 480:
      case 487:
         return AST_REDIRECTING_REASON_DEFLECTION;
      case 503:
         return AST_REDIRECTING_REASON_UNAVAILABLE;
      default:
         return AST_REDIRECTING_REASON_UNKNOWN;
   }
}

static int add_supported(pjsip_tx_data *tdata)
{
   pjsip_supported_hdr *hdr;
   unsigned int i;

   hdr = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_SUPPORTED, NULL);
   if (!hdr) {
      /* insert a new Supported header */
      hdr = pjsip_supported_hdr_create(tdata->pool);
      if (!hdr) {
         return -1;
      }

      pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr *)hdr);
   }

   /* Asterisk can send multiple "181 Call forwarded" in a single session,
    * we might have already modified Supported before
    */
   for (i = 0; i < hdr->count; ++i) {
      if (pj_stricmp(&hdr->values[i], &HISTINFO_SUPPORTED_NAME) == 0) {
         return 0;
      }
   }

   if (hdr->count >= PJSIP_GENERIC_ARRAY_MAX_COUNT) {
      return -1;
   }

   /* add on to the existing Supported header */
   pj_strassign(&hdr->values[hdr->count++], &HISTINFO_SUPPORTED_NAME);

   return 0;
}

static const char *reason_code_to_str(const struct ast_party_redirecting_reason *reason)
{
   int idx;
   int code;

   /* use specific string if given */
   if (!ast_strlen_zero(reason->str)) {
      return reason->str;
   }

   code = reason->code;
   for (idx = 0; idx < ARRAY_LEN(reason_table); ++idx) {
      if (code == reason_table[idx].code) {
         return reason_table[idx].text;
      }
   }

   return "unknown";
}

static const unsigned int reason_code_to_cause(const struct ast_party_redirecting_reason *reason)
{
   int idx;
   int code;

   code = reason->code;
   for (idx = 0; idx < ARRAY_LEN(reason_table); ++idx) {
      if (code == reason_table[idx].code) {
         return reason_table[idx].cause;
      }
   }

   return 404;
}

static pjsip_fromto_hdr *get_diversion_header(pjsip_rx_data *rdata)
{
   static const pj_str_t from_name = { "From", 4 };

   pjsip_generic_string_hdr *hdr;
   pj_str_t value;
   int size;

   if (!(hdr = pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &diversion_name, NULL))) {
      return NULL;
   }

   pj_strdup_with_null(rdata->tp_info.pool, &value, &hdr->hvalue);

   /* parse as a fromto header */
   return pjsip_parse_hdr(rdata->tp_info.pool, &from_name, value.ptr,
                pj_strlen(&value), &size);
}

/* Asterisk keeps track of 2 things. The redirected from address and
 * the redirected to address. If first=0 method will get the most recent
 * redirection target for use as the redirected to address. If first=1
 * then this method will get the original redirection target (index=1)
 * for use as the redirected from address.
 */
static pjsip_fromto_hdr *get_history_info_header(pjsip_rx_data *rdata, const unsigned int first)
{
   static const pj_str_t from_name = { "From", 4 };
   pjsip_fromto_hdr * result_hdr = NULL;

   pjsip_generic_string_hdr *hdr = NULL;

   hdr = pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &history_info_name, NULL);

   if (!hdr) {
      return NULL;
   }

   do {
      static const pj_str_t index_name = { "index", 5 };
      pj_str_t value;
      int size;
      pjsip_fromto_hdr * fromto_hdr = NULL;
      pjsip_param * index = NULL;

      pj_strdup_with_null(rdata->tp_info.pool, &value, &hdr->hvalue);

      /* parse as a fromto header */
      fromto_hdr =  pjsip_parse_hdr(rdata->tp_info.pool, &from_name, value.ptr,
                   pj_strlen(&value), &size);

      if (fromto_hdr == NULL) {
         continue;
      }

      index = pjsip_param_find(&fromto_hdr->other_param, &index_name);

      if (index) {
         if (!pj_strcmp2(&index->value, "1")) {
            if (!first) {
               continue;
            } else {
               return fromto_hdr;
            }
         }
      }

      result_hdr = fromto_hdr;

   } while ((hdr = pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &history_info_name, hdr->next)));

   return result_hdr;
}

static void set_redirecting_value(char **dst, const pj_str_t *src)
{
   ast_free(*dst);
   *dst = ast_malloc(pj_strlen(src) + 1);
   if (*dst) {
      ast_copy_pj_str(*dst, src, pj_strlen(src) + 1);
   }
}

static void set_redirecting_id(pjsip_name_addr *name_addr, struct ast_party_id *data,
                struct ast_set_party_id *update)
{
   pjsip_sip_uri *uri = pjsip_uri_get_uri(name_addr->uri);
   char *semi;
   pj_str_t uri_user;

   uri_user = uri->user;

   /* Always truncate redirecting number at a semicolon. */
   semi = pj_strchr(&uri_user, ';');
   if (semi) {
      /*
       * We need to be able to handle URI's looking like
       * "sip:1235557890;[email protected];user=phone"
       *
       * Where the uri->user field will result in:
       * "1235557890;phone-context=national"
       *
       * People don't care about anything after the semicolon
       * showing up on their displays even though the RFC
       * allows the semicolon.
       */
      pj_strset(&uri_user, (char *) pj_strbuf(&uri_user), semi - pj_strbuf(&uri_user));
   }

   if (pj_strlen(&uri_user)) {
      update->number = 1;
      data->number.valid = 1;
      set_redirecting_value(&data->number.str, &uri_user);
   }

   if (pj_strlen(&name_addr->display)) {
      update->name = 1;
      data->name.valid = 1;
      set_redirecting_value(&data->name.str, &name_addr->display);
   }
}

static void copy_redirecting_id(struct ast_party_id *dst, const struct ast_party_id *src,
            struct ast_set_party_id *update)
{
   ast_party_id_copy(dst, src);

   if (dst->number.valid) {
      update->number = 1;
   }

   if (dst->name.valid) {
      update->name = 1;
   }
}

static void set_redirecting_reason_by_cause(pjsip_name_addr *name_addr,
               struct ast_party_redirecting_reason *data)
{
   static const pj_str_t cause_name = { "cause", 5 };
   pjsip_sip_uri *uri = pjsip_uri_get_uri(name_addr);
   pjsip_param *cause = NULL;
   unsigned long cause_value = 0;

   if (!PJSIP_URI_SCHEME_IS_SIP(uri) && !PJSIP_URI_SCHEME_IS_SIPS(uri)) {
      return;
   }

   cause = pjsip_param_find(&uri->other_param, &cause_name);

   if (!cause) {
      return;
   }

   cause_value = pj_strtoul(&cause->value);

   data->code = cause_to_reason(cause_value);
   ast_free(data->str);
   data->str = ast_strdup("");
}

static void set_redirecting_reason(pjsip_fromto_hdr *from_info, pjsip_name_addr *to_info,
               struct ast_party_redirecting_reason *data)
{
   static const pj_str_t reason_name = { "reason", 6 };
   pjsip_param *reason = pjsip_param_find(&from_info->other_param, &reason_name);
   char *reason_str;

   if (!reason) {
      if (to_info) {
         set_redirecting_reason_by_cause(to_info, data);
      }
      return;
   }

   set_redirecting_value(&data->str, &reason->value);
   if (!data->str) {
      /* Oops, allocation failure */
      return;
   }
   reason_str = ast_strdupa(data->str);

   /* Remove any enclosing double-quotes */
   if (*reason_str == '"') {
      reason_str = ast_strip_quoted(reason_str, "\"", "\"");
   }

   data->code = ast_redirecting_reason_parse(reason_str);
   if (data->code < 0) {
      data->code = AST_REDIRECTING_REASON_UNKNOWN;
   } else {
      ast_free(data->str);
      data->str = ast_strdup("");
   }
}

static void set_redirecting(struct ast_sip_session *session,
             pjsip_fromto_hdr *from_info,
             pjsip_name_addr *to_info)
{
   struct ast_party_redirecting data;
   struct ast_set_party_redirecting update;

   if (!session->channel) {
      return;
   }

   ast_party_redirecting_init(&data);
   memset(&update, 0, sizeof(update));

   data.reason.code = AST_REDIRECTING_REASON_UNKNOWN;
   if (from_info) {
      set_redirecting_id((pjsip_name_addr*)from_info->uri,
         &data.from, &update.from);
      set_redirecting_reason(from_info, to_info, &data.reason);
      ast_set_party_id_all(&update.priv_to);
   } else {
      copy_redirecting_id(&data.from, &session->id, &update.from);
   }

   if (to_info) {
      set_redirecting_id(to_info, &data.to, &update.to);
   }

   ast_set_party_id_all(&update.priv_orig);
   ast_set_party_id_all(&update.priv_from);
   ast_set_party_id_all(&update.priv_to);
   ++data.count;

   ast_channel_set_redirecting(session->channel, &data, &update);
   /* Only queue an indication if it was due to a response */
   if (session->inv_session->role == PJSIP_ROLE_UAC) {
      ast_channel_queue_redirecting_update(session->channel, &data, &update);
   }
   ast_party_redirecting_free(&data);
}

static int diversion_incoming_request(struct ast_sip_session *session, pjsip_rx_data *rdata)
{
   pjsip_fromto_hdr *hdr = get_diversion_header(rdata);

   if (hdr) {
      set_redirecting(session, hdr, (pjsip_name_addr*)
            PJSIP_MSG_TO_HDR(rdata->msg_info.msg)->uri);
   } else {
      pjsip_fromto_hdr *history_info_to;
      pjsip_fromto_hdr *history_info_from;
      history_info_to  = get_history_info_header(rdata, 0);

      if (history_info_to) {
         /* If History-Info is present, then it will also include the original
            redirected-from in addition to the redirected-to */
         history_info_from = get_history_info_header(rdata, 1);
         set_redirecting(session, history_info_from, (pjsip_name_addr*)history_info_to->uri);
      }
   }

   return 0;
}

static void diversion_incoming_response(struct ast_sip_session *session, pjsip_rx_data *rdata)
{
   static const pj_str_t contact_name = { "Contact", 7 };
   static const pj_str_t contact_name_s = { "m", 1 };

   pjsip_status_line status = rdata->msg_info.msg->line.status;
   pjsip_fromto_hdr *div_hdr;
   pjsip_fromto_hdr *history_info_to;
   pjsip_fromto_hdr *history_info_from;
   pjsip_contact_hdr *contact_hdr;

   if ((status.code != 302) && (status.code != 181)) {
      return;
   }

   /* use the diversion header info if there is one. if not one then use the
      the history-info, if that doesn't exist, use session caller id info. if
      that doesn't exist use info from the To hdr*/
   if (!(div_hdr = get_diversion_header(rdata))) {
      history_info_to  = get_history_info_header(rdata, 0);

      if (history_info_to) {
         /* If History-Info is present, then it will also include the original
            redirected-from in addition to the redirected-to */
         history_info_from = get_history_info_header(rdata, 1);
         set_redirecting(session, history_info_from, (pjsip_name_addr*)history_info_to->uri);
         return;
      }
      if (!div_hdr && !session->id.number.valid) {
         div_hdr = PJSIP_MSG_TO_HDR(rdata->msg_info.msg);
      }
   }


   if (status.code == 302) {
      /* With 302, Contact indicates the final destination and possibly Diversion indicates the hop before */
      contact_hdr = pjsip_msg_find_hdr_by_names(rdata->msg_info.msg, &contact_name, &contact_name_s, NULL);

      set_redirecting(session, div_hdr, contact_hdr ? (pjsip_name_addr*)contact_hdr->uri :
            (pjsip_name_addr*)PJSIP_MSG_FROM_HDR(rdata->msg_info.msg)->uri);
   } else {
      /* With 181, Diversion is non-standard, but if present indicates the new final destination, and To indicating the original */
      set_redirecting(session, PJSIP_MSG_TO_HDR(rdata->msg_info.msg),
            div_hdr ? (pjsip_name_addr*)div_hdr->uri : NULL);
   }
}

/*!
 * \internal
 * \brief Adds diversion header information to an outbound SIP message
 *
 * \param tdata The outbound message
 * \param data The redirecting data used to fill parts of the diversion header
 */
static void add_diversion_header(pjsip_tx_data *tdata, struct ast_party_redirecting *data)
{
   static const pj_str_t reason_name = { "reason", 6 };

   pjsip_fromto_hdr *hdr;
   pjsip_name_addr *name_addr;
   pjsip_sip_uri *uri;
   pjsip_param *param;
   pjsip_fromto_hdr *old_hdr;
   const char *reason_str;
   const char *quote_str;
   char *reason_buf;
   pjsip_uri *base;

   struct ast_party_id *id = NULL;
   if (tdata->msg->type == PJSIP_REQUEST_MSG) {
      id = &data->from;
   } else {
      /* In responses indicate the new destination */
      id = &data->to;
   }

   base = PJSIP_MSG_FROM_HDR(tdata->msg)->uri;

   if (!id->number.valid || ast_strlen_zero(id->number.str)) {
      return;
   }

   hdr = pjsip_from_hdr_create(tdata->pool);
   hdr->type = PJSIP_H_OTHER;
   hdr->sname = hdr->name = diversion_name;

   name_addr = pjsip_uri_clone(tdata->pool, base);
   uri = pjsip_uri_get_uri(name_addr->uri);

   pj_strdup2(tdata->pool, &name_addr->display, id->name.str);
   pj_strdup2(tdata->pool, &uri->user, id->number.str);

   param = PJ_POOL_ALLOC_T(tdata->pool, pjsip_param);
   param->name = reason_name;

   reason_str = reason_code_to_str(&data->reason);

   /* Reason is either already quoted or it is a token to not need quotes added. */
   quote_str = *reason_str == '\"' || sip_is_token(reason_str) ? "" : "\"";

   reason_buf = pj_pool_alloc(tdata->pool, strlen(reason_str) + 3);
   sprintf(reason_buf, "%s%s%s", quote_str, reason_str, quote_str);/* Safe */

   param->value = pj_str(reason_buf);

   pj_list_insert_before(&hdr->other_param, param);

   hdr->uri = (pjsip_uri *) name_addr;
   old_hdr = pjsip_msg_find_hdr_by_name(tdata->msg, &diversion_name, NULL);
   if (old_hdr) {
      pj_list_erase(old_hdr);
   }
   pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr *)hdr);
}

/*!
 * \internal
 * \brief Adds history-info header information to an outbound SIP message
 *
 * \param tdata The outbound message
 * \param data The redirecting data used to fill parts of the history-info header
 */
static void add_history_info_header(pjsip_tx_data *tdata, struct ast_party_redirecting *data)
{
   static const pj_str_t index_name = { "index", 5 };
   static const pj_str_t cause_name = { "cause", 5 };
   static const pj_str_t first_index = { "1", 1 };
   static const pj_str_t last_index = { "1.1", 3 };

   pjsip_fromto_hdr *hdr;
   pjsip_name_addr *name_addr;
   pjsip_sip_uri *uri;
   pjsip_param *param;
   pjsip_fromto_hdr *old_hdr;
   unsigned int cause;
   char *cause_buf;

   struct ast_party_id *to = &data->to;
   struct ast_party_id *from = &data->from;

   pjsip_uri *base = PJSIP_MSG_TO_HDR(tdata->msg)->uri;


   hdr = pjsip_from_hdr_create(tdata->pool);
   hdr->type = PJSIP_H_OTHER;
   hdr->sname = hdr->name = history_info_name;

   name_addr = pjsip_uri_clone(tdata->pool, base);
   uri = pjsip_uri_get_uri(name_addr->uri);

   /* if no redirecting information, then TO is the original destination */
   if (from->number.valid && !ast_strlen_zero(from->number.str)) {
      pj_strdup2(tdata->pool, &name_addr->display, from->name.str);
      pj_strdup2(tdata->pool, &uri->user, from->number.str);
   }

   param = PJ_POOL_ALLOC_T(tdata->pool, pjsip_param);
   param->name = index_name;
   param->value = first_index;


   pj_list_insert_before(&hdr->other_param, param);
   hdr->uri = (pjsip_uri *) name_addr;

   while ((old_hdr = pjsip_msg_find_hdr_by_name(tdata->msg, &history_info_name, NULL)) != NULL) {
      pj_list_erase(old_hdr);
   }

   pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr *)hdr);

   if (!to->number.valid || ast_strlen_zero(to->number.str)) {
      return;
   }

   hdr = pjsip_from_hdr_create(tdata->pool);
   hdr->type = PJSIP_H_OTHER;
   hdr->sname = hdr->name = history_info_name;

   name_addr = pjsip_uri_clone(tdata->pool, base);
   uri = pjsip_uri_get_uri(name_addr->uri);

   pj_strdup2(tdata->pool, &name_addr->display, to->name.str);
   pj_strdup2(tdata->pool, &uri->user, to->number.str);

   param = PJ_POOL_ALLOC_T(tdata->pool, pjsip_param);
   param->name = index_name;
   param->value = last_index;
   pj_list_insert_before(&hdr->other_param, param);

   param = PJ_POOL_ALLOC_T(tdata->pool, pjsip_param);
   param->name = cause_name;
   cause = reason_code_to_cause(&data->reason);
   cause_buf = pj_pool_alloc(tdata->pool, 4);
   snprintf(cause_buf, 4, "%ud", cause);
   param->value = pj_str(cause_buf);
   pj_list_insert_before(&uri->other_param, param);
   hdr->uri = (pjsip_uri *) name_addr;

   pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr *)hdr);
}

static void get_redirecting_add_diversion(struct ast_sip_session *session, pjsip_tx_data *tdata)
{
   struct ast_party_redirecting *data;

   add_supported(tdata);

   if (session->channel && session->endpoint->id.send_diversion &&
       (data = ast_channel_redirecting(session->channel))->count) {
      add_diversion_header(tdata, data);
   }
   if (session->channel && session->endpoint->id.send_history_info) {
      data = ast_channel_redirecting(session->channel);
      add_history_info_header(tdata, data);
   }
}

/*!
 * \internal
 * \brief Adds a diversion header to an outgoing INVITE request if
 *  redirecting information is available.
 *
 * \param session The session on which the INVITE request is to be sent
 * \param tdata The outbound INVITE request
 */
static void diversion_outgoing_request(struct ast_sip_session *session, pjsip_tx_data *tdata)
{
   get_redirecting_add_diversion(session, tdata);
}

/*!
 * \internal
 * \brief Adds a diversion header to an outgoing 3XX response
 *
 * \param session The session on which the INVITE response is to be sent
 * \param tdata The outbound INVITE response
 */
static void diversion_outgoing_response(struct ast_sip_session *session, pjsip_tx_data *tdata)
{
   struct pjsip_status_line status = tdata->msg->line.status;

   /* add to 302 and 181 */
   if (PJSIP_IS_STATUS_IN_CLASS(status.code, 300) || (status.code == 181)) {
      get_redirecting_add_diversion(session, tdata);
   }
}

static struct ast_sip_session_supplement diversion_supplement = {
   .method = "INVITE",
   /* this supplement needs to be called after caller id
           and after the channel has been created */
   .priority = AST_SIP_SUPPLEMENT_PRIORITY_CHANNEL + 100,
   .incoming_request = diversion_incoming_request,
   .incoming_response = diversion_incoming_response,
   .outgoing_request = diversion_outgoing_request,
   .outgoing_response = diversion_outgoing_response,
   .response_priority = AST_SIP_SESSION_BEFORE_MEDIA,
};

static int load_module(void)
{
   /* Because we are passing static memory to pjsip, we need to make sure it
    * stays valid while we potentially have active sessions */
   ast_module_shutdown_ref(ast_module_info->self);
   ast_sip_session_register_supplement(&diversion_supplement);
   return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module(void)
{
   ast_sip_session_unregister_supplement(&diversion_supplement);
   return 0;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP Add Diversion Header Support",
   .support_level = AST_MODULE_SUPPORT_CORE,
   .load = load_module,
   .unload = unload_module,
   .load_pri = AST_MODPRI_APP_DEPEND,
   .requires = "res_pjsip,res_pjsip_session",
);