xmpp_server.c

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/*
 * $Id: xmpp_server.c 4585 2008-08-06 08:20:30Z klaus_darilion $
 *
 * XMPP Module
 * This file is part of Kamailio, a free SIP server.
 *
 * Copyright (C) 2006 Voice Sistem S.R.L.
 *
 * 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
 *
 * Author: Andreea Spirea
 *
 */
/*! \file
 * \brief Kamailio XMPP :: XMPP server implementation (limited functionality)
 *  \ingroup xmpp
 */

/*
 * An inbound SIP message:
 *   from sip:user1@domain1 to sip:user2*domain2@gateway_domain
 * is translated to an XMPP message:
 *   from user1*domain1@xmpp_domain to user2@domain2
 *
 * An inbound XMPP message:
 *   from user1@domain1 to user2*domain2@xmpp_domain
 * is translated to a SIP message:
 *   from sip:user1*domain1@gateway_domain to sip:user2@domain2
 *
 * Where '*' is the domain_separator, and gateway_domain and
 * xmpp_domain are defined below.
 */

/*
 * 2-way dialback sequence with xmppd2:
 *
 *  Originating server (us)         Receiving server (them)      Authoritative server (us)
 *  -----------------------         -----------------------      -------------------------
 *           |                               |                               |
 *           |    establish connection       |                               |
 *           |------------------------------>|                               |
 *           |    send stream header         |                               |
 *           |------------------------------>|                               |
 *           |    send stream header         |                               |
 *           |<------------------------------|                               |
 *           |    send db:result request     |                               |
 *           |------------------------------>|                               |
 *                                           |    establish connection       |
 *                                           |------------------------------>|
 *                                           |    send stream header         |
 *                                           |------------------------------>|
 *                                           |    send stream header         |
 *                                           |<------------------------------|
 *                                           |    send db:result request     |
 *                                           |------------------------------>|
 *           |    send db:verify request     |
 *           |------------------------------>|
 *           |    send db:verify response    |
 *           |<------------------------------|
 *                                           |    send db:result response    |
 *                                           |------------------------------>|
 *                                           |    send db:verify request     |
 *                                           |<------------------------------|
 *                                           |    send db:verify response    |
 *                                           |------------------------------>|
 *           |    send db:result response    |
 *           |<------------------------------|
 *           :                               :                               :
 *           :                               :                               :
 *           |    outgoing <message/>        |                               :
 *           |------------------------------>|                               :
 *                                           |    incoming <message/>        |
 *                                           |------------------------------>|
 */

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>

#include "../../sr_module.h"

#include "xmpp.h"
#include "xmpp_api.h"
#include "network.h"
#include "xode.h"

#include <arpa/inet.h>

/* XXX hack */
#define DB_KEY "this-be-a-random-key"

#define CONN_DEAD 0
#define CONN_INBOUND 1
#define CONN_OUTBOUND   2

struct xmpp_private_data {
   int fd;     /* outgoing stream socket */
   int listen_fd; /* listening socket */
   int in_fd;  /* incoming stream socket */
   int running;
};

struct xmpp_connection {
   struct xmpp_connection *next;

   char *domain;
   int type;
   int fd;
   char *stream_id;
   xode_pool pool;
   xode_stream stream;
   xode todo;  /* backlog of outgoing messages, if any */
};

static char local_secret[64] = { 0, };

static void in_stream_node_callback(int type, xode node, void *arg);
static void out_stream_node_callback(int type, xode node, void *arg);

static struct xmpp_connection *conn_list = NULL;

static struct xmpp_connection *conn_new(int type, int fd, char *domain)
{
   struct xmpp_connection *conn = NULL;
   
   conn = malloc(sizeof(struct xmpp_connection));

   if(conn==NULL) 
   {
      LM_ERR("out of memory\n");
      return NULL;
   }
   
   memset(conn, 0, sizeof(struct xmpp_connection));
   conn->domain = domain ? strdup(domain) : NULL;
   conn->type = type;
   conn->fd = fd;
   conn->todo = xode_new_tag("todo");

   conn->pool = xode_pool_new();
   conn->stream = xode_stream_new(conn->pool,
      (type==CONN_INBOUND)?in_stream_node_callback:out_stream_node_callback,
      conn);
   
   conn->next = conn_list;
   conn_list = conn;
   return conn;
}

static void conn_free(struct xmpp_connection *conn)
{
   struct xmpp_connection **last_p, *link;
   
   last_p = &conn_list;
   for (link = conn_list; link; link = link->next) {
      if (link == conn) {
         *last_p = link->next;
         break;
      }
      last_p = &link->next;
   }

   if (conn->todo)
      xode_free(conn->todo);
   xode_pool_free(conn->pool);
   if (conn->fd != -1)
      close(conn->fd);
   if (conn->stream_id)
      free(conn->stream_id);
   if (conn->domain)
      free(conn->domain);
   free(conn);
}

static struct xmpp_connection *conn_find_domain(char *domain, int type)
{
   struct xmpp_connection *conn;
   
   for (conn = conn_list; conn; conn = conn->next)
      if (conn->domain && !strcasecmp(conn->domain, domain) 
            && conn->type == type)
         return conn;
   return NULL;
}

/*
static struct xmpp_connection *conn_find_fd(int fd)
{
   struct xmpp_connection *conn;
   
   for (conn = conn_list; conn; conn = conn->next)
      if (conn->fd == fd)
         return conn;
   return NULL;
}
*/

/*****************************************************************************/

static int xode_send(int fd, xode x)
{
   char *str = xode_to_str(x);
   int len = strlen(str);
   
   LM_DBG("xode_send->%d [%s]\n", fd, str);

   if (net_send(fd, str, len) != len) {
      LM_ERR("send() failed: %s\n", strerror(errno));
      return -1;
   }
   return len;
}

static int xode_send_domain(char *domain, xode x)
{
   struct xmpp_connection *conn;

   if ((conn = conn_find_domain(domain, CONN_OUTBOUND))) {
      xode_send(conn->fd, x);
      xode_free(x);
   } else {
      if((conn = conn_new(CONN_OUTBOUND, -1, domain))==0)
         return -1;
      xode_insert_node(conn->todo, x);
   }
   return 1;
}

static void out_stream_node_callback(int type, xode node, void *arg)
{
   struct xmpp_connection *conn = (struct xmpp_connection *) arg;
   struct xmpp_connection *in_conn = NULL;
   char *tag;
   xode x;

   LM_DBG("outstream callback: %d: %s\n", type, 
         node?xode_get_name(node):"n/a");

   if (conn->domain)
      in_conn = conn_find_domain(conn->domain, CONN_INBOUND);

   switch (type) {
   case XODE_STREAM_ROOT:
      x = xode_new_tag("db:result");
      xode_put_attrib(x, "xmlns:db", "jabber:server:dialback");
      xode_put_attrib(x, "from", xmpp_domain);
      xode_put_attrib(x, "to", conn->domain);
      //xode_insert_cdata(x, DB_KEY, -1);
      xode_insert_cdata(x, db_key(local_secret, conn->domain,
               xode_get_attrib(node, "id")), -1);
      xode_send(conn->fd, x);
      xode_free(x);

      break;
   case XODE_STREAM_NODE:
      tag = xode_get_name(node);

      if (!strcmp(tag, "db:verify")) {
         char *from = xode_get_attrib(node, "from");
         char *to = xode_get_attrib(node, "to");
         char *id = xode_get_attrib(node, "id");
         char *type = xode_get_attrib(node, "type");
         /* char *cdata = xode_get_data(node); */
         
         if (!strcmp(type, "valid") || !strcmp(type, "invalid")) {
            /* got a reply, report it */
            x = xode_new_tag("db:result");
            xode_put_attrib(x, "xmlns:db", "jabber:server:dialback");
            xode_put_attrib(x, "from", to);
            xode_put_attrib(x, "to", from);
            xode_put_attrib(x, "id", id);
            xode_put_attrib(x, "type", type);
            if (in_conn)
               xode_send(in_conn->fd, x);
            else
               LM_ERR("need to send reply to domain '%s', but no inbound"
                     " connection found\n", from);
            xode_free(x);
         }
      } else if (!strcmp(tag, "db:result")) {
         char *type = xode_get_attrib(node, "type");
         
         if (type && !strcmp(type, "valid")) {
            /* the remote server has successfully authenticated us,
             * we can now send data */
            for (x = xode_get_firstchild(conn->todo); x;
                  x = xode_get_nextsibling(x)) {
               LM_DBG("sending todo tag '%s'\n", xode_get_name(x));
               xode_send(conn->fd, x);
            }
            xode_free(conn->todo);
            conn->todo = NULL;
         }
      }
      break;
   case XODE_STREAM_ERROR:
      LM_ERR("outstream error\n");
      /* fall-through */
   case XODE_STREAM_CLOSE:
      conn->type = CONN_DEAD;
      break;
   }
   xode_free(node);
}

static void in_stream_node_callback(int type, xode node, void *arg) 
{
   struct xmpp_connection *conn = (struct xmpp_connection *) arg;
   char *tag;
   xode x;

   LM_DBG("instream callback: %d: %s\n",
         type, node ? xode_get_name(node) : "n/a");
   switch (type) {
   case XODE_STREAM_ROOT:
      conn->stream_id = strdup(random_secret());
      net_printf(conn->fd,
         "<?xml version='1.0'?>"
         "<stream:stream xmlns:stream='http://etherx.jabber.org/streams' xmlns='jabber:server' version='1.0'"
         " xmlns:db='jabber:server:dialback' id='%s' from='%s'>", conn->stream_id, xmpp_domain);
      net_printf(conn->fd,"<stream:features xmlns:stream='http://etherx.jabber.org/streams'/>");
      break;
   case XODE_STREAM_NODE:
      tag = xode_get_name(node);

      if (!strcmp(tag, "db:result")) {
         char *from = xode_get_attrib(node, "from");
         char *to = xode_get_attrib(node, "to");
         /* char *id = xode_get_attrib(node, "id"); */
         char *type = xode_get_attrib(node, "type");
         char *cdata = xode_get_data(node);
         
         if (!type) {
            if (conn->domain) {
               LM_DBG("connection %d has old domain '%s'\n",conn->fd,
                     conn->domain);
               free(conn->domain);
            }
            conn->domain = strdup(from);
            LM_DBG("connection %d set domain '%s'\n",
                  conn->fd, conn->domain);

            /* it's a request; send verification over outgoing connection */
            x = xode_new_tag("db:verify");
            xode_put_attrib(x, "xmlns:db", "jabber:server:dialback");
            xode_put_attrib(x, "from", to);
            xode_put_attrib(x, "to", from);
            //xode_put_attrib(x, "id", "someid"); /* XXX fix ID */
            xode_put_attrib(x, "id", conn->stream_id);
            xode_insert_cdata(x, cdata, -1);
            xode_send_domain(from, x);
         }        
      } else if (!strcmp(tag, "db:verify")) {
         char *from = xode_get_attrib(node, "from");
         char *to = xode_get_attrib(node, "to");
         char *id = xode_get_attrib(node, "id");
         char *type = xode_get_attrib(node, "type");
         char *cdata = xode_get_data(node);
         
         if (!type) {
            /* it's a request */
            x = xode_new_tag("db:verify");
            xode_put_attrib(x, "xmlns:db", "jabber:server:dialback");
            xode_put_attrib(x, "from", to);
            xode_put_attrib(x, "to", from);
            xode_put_attrib(x, "id", id);
            //if (cdata && !strcmp(cdata, DB_KEY)) {
            if (cdata && !strcmp(cdata, db_key(local_secret, from, id))) {
               xode_put_attrib(x, "type", "valid");
            } else {
               xode_put_attrib(x, "type", "invalid");
            }
            xode_send(conn->fd, x);
            xode_free(x);
         }        
      } else if (!strcmp(tag, "message")) {
         char *from = xode_get_attrib(node, "from");
         char *to = xode_get_attrib(node, "to");
         char *type = xode_get_attrib(node, "type");
         xode body = xode_get_tag(node, "body");
         char *msg;
         
         if (!type)
            type = "chat";
         if (!strcmp(type, "error")) { 
            LM_DBG("received message error stanza\n");
            goto out;
         }
         
         if (!from || !to || !body) {
            LM_DBG("invalid <message/> attributes\n");
            goto out;
         }

         if (!(msg = xode_get_data(body)))
            msg = "";
         xmpp_send_sip_msg(
            encode_uri_xmpp_sip(from),
            decode_uri_xmpp_sip(to),
            msg);
      } else if (!strcmp(tag, "presence")) {
         /* run presence callbacks */
      }
      break;

      break;
   case XODE_STREAM_ERROR:
      LM_ERR("instream error\n");
      /* fall-through */
   case XODE_STREAM_CLOSE:
      conn->type = CONN_DEAD;
      break;
   }
out:
   xode_free(node);
}

static void do_send_message_server(struct xmpp_pipe_cmd *cmd)
{
   char *domain;
   xode x;

   LM_DBG("rom=[%s] to=[%s] body=[%s]\n", cmd->from,cmd->to, cmd->body);

   x = xode_new_tag("message");
   xode_put_attrib(x, "xmlns", "jabber:client");
   xode_put_attrib(x, "id", cmd->id); // XXX
   xode_put_attrib(x, "from", encode_uri_sip_xmpp(cmd->from));
   xode_put_attrib(x, "to", decode_uri_sip_xmpp(cmd->to));
   xode_put_attrib(x, "type", "chat");
   xode_insert_cdata(xode_insert_tag(x, "body"), cmd->body, -1);

   domain = extract_domain(decode_uri_sip_xmpp(cmd->to));
   xode_send_domain(domain, x);
}

int xmpp_server_child_process(int data_pipe)
{
   int rv;
   int listen_fd;
   fd_set fdset;
   struct xmpp_connection *conn;
   
   snprintf(local_secret, sizeof(local_secret), "%s", random_secret());

   while ((listen_fd = net_listen(xmpp_domain, xmpp_port)) < 0) {
      /* ugh. */
      sleep(3);
   }

   while (1) {
      FD_ZERO(&fdset);
      FD_SET(data_pipe, &fdset);
      FD_SET(listen_fd, &fdset);
      
      /* check for dead connections */
      for (conn = conn_list; conn; ) {
         struct xmpp_connection *next = conn->next;

         if (conn->type == CONN_DEAD)
            conn_free(conn);
         conn = next;
      }

      for (conn = conn_list; conn; conn = conn->next) {
         /* check if we need to set up a connection */
         if (conn->type == CONN_OUTBOUND && conn->fd == -1) {
            if ((conn->fd = net_connect(conn->domain, xmpp_port)) >= 0)
            {
               net_printf(conn->fd,
                  "<?xml version='1.0'?>"
                  "<stream:stream xmlns:stream='http://etherx.jabber.org/streams' xmlns='jabber:server' version='1.0' "
                  "xmlns:db='jabber:server:dialback' to='%s' from='%s'>",
                  conn->domain, xmpp_domain);
               net_printf(conn->fd,
                           "<stream:features xmlns:stream='http://etherx.jabber.org/streams'/>");
            } else {
               conn->type = CONN_DEAD;
            }
         }     

         if (conn->fd != -1)
            FD_SET(conn->fd, &fdset);
      }

      rv = select(FD_SETSIZE, &fdset, NULL, NULL, NULL);
      if (rv < 0) {
         LM_ERR("select() failed: %s\n", strerror(errno));
      } else if (!rv) {
         /* timeout */
      } else {
         for (conn = conn_list; conn; conn = conn->next) {
            if (conn->fd != -1 && FD_ISSET(conn->fd, &fdset)) {
               char *buf = net_read_static(conn->fd);
               if (!buf) {
                  conn->type = CONN_DEAD;
               } else {
                  LM_DBG("stream (fd %d, domain '%s') read\n[%s]\n",
                        conn->fd, conn->domain, buf);
                  xode_stream_eat(conn->stream, buf, strlen(buf));
               }
            }
         }

         if (FD_ISSET(listen_fd, &fdset)) {
            struct sockaddr_in sin;
            unsigned int len = sizeof(sin);
            int fd;

            if ((fd = accept(listen_fd,(struct sockaddr*)&sin, &len))<0) {
               LM_ERR("accept() failed: %s\n", strerror(errno));
            } else {
               LM_DBG("accept()ed connection from %s:%d\n",
                     inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
               conn_new(CONN_INBOUND, fd, NULL);
            }
         }

         if (FD_ISSET(data_pipe, &fdset)) {
            struct xmpp_pipe_cmd *cmd;

            if (read(data_pipe, &cmd, sizeof(cmd)) != sizeof(cmd)) {
               LM_ERR("failed to read from command pipe: %s\n",
                     strerror(errno));
            } else {
               LM_DBG("got pipe cmd %d\n", cmd->type);
               switch (cmd->type) {
               case XMPP_PIPE_SEND_MESSAGE:
                  do_send_message_server(cmd);
                  break;
               case XMPP_PIPE_SEND_PACKET:
               case XMPP_PIPE_SEND_PSUBSCRIBE:
               case XMPP_PIPE_SEND_PNOTIFY:
                  break;
               }
               xmpp_free_pipe_cmd(cmd);
            }
         }
      }
   }
   return 0;
}