cpl_proxy.h

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/*
 * $Id: cpl_proxy.h 5376 2008-12-17 19:07:14Z osas $
 *
 * Copyright (C) 2001-2003 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
 *
 * History:
 * -------
 * 2003-07-29: file created (bogdan)
 * 2004-06-14: flag CPL_IS_STATEFUL is set now immediately after the 
 *             transaction is created (bogdan)
 */

#include "../tm/h_table.h"
#include "../../parser/contact/parse_contact.h"


#define duplicate_str( _orig_ , _new_ ) \
   do {\
      (_new_) = (str*)shm_malloc(sizeof(str)+(_orig_)->len);\
      if (!(_new_)) goto mem_error;\
      (_new_)->len = (_orig_)->len;\
      (_new_)->s = (char*)((_new_))+sizeof(str);\
      memcpy((_new_)->s,(_orig_)->s,(_orig_)->len);\
   } while(0)

#define search_and_duplicate_hdr( _intr_ , _field_ , _name_ , _sfoo_ ) \
   do {\
      if (!(_intr_)->_field_) {\
         if (!(_intr_)->msg->_field_) { \
            if (parse_headers((_intr_)->msg,_name_,0)==-1) {\
               LM_ERR("bad %llx hdr\n",_name_);\
               goto runtime_error;\
            } else if ( !(_intr_)->msg->_field_) {\
               (_intr_)->_field_ = STR_NOT_FOUND;\
            } else {\
               (_sfoo_) = &((_intr_)->msg->_field_->body);\
               duplicate_str( (_sfoo_) , (_intr_)->_field_ );\
            }\
         } else {\
            (_sfoo_) = &((_intr_)->msg->_field_->body);\
            duplicate_str( (_sfoo_) , (_intr_)->_field_ );\
         }\
      } else {\
         (_sfoo_) = (_intr_)->_field_;\
         duplicate_str( (_sfoo_) , (_intr_)->_field_ );\
      }\
   }while(0)



static inline int parse_q(str *q, unsigned int *prio)
{
   if (q->s[0]=='0')
      *prio=0;
   else if (q->s[0]=='1')
      *prio=10;
   else
      goto error;
   if (q->s[1]!='.')
      goto error;
   if (q->s[2]<'0' || q->s[2]>'9')
      goto error;
   *prio += q->s[2] - '0';
   if (*prio>10)
      goto error;

   return 0;
error:
   LM_ERR("bad q param <%.*s>\n",q->len,q->s);
   return -1;
}



static inline int add_contacts_to_loc_set(struct sip_msg* msg,
                                       struct location **loc_set)
{
   struct sip_uri uri;
   struct contact *contacts;
   unsigned int prio;

   /* we need to have the contact header */
   if (msg->contact==0) {
      /* find and parse the Contact header */
      if ((parse_headers(msg, HDR_CONTACT_F, 0)==-1) || (msg->contact==0)) {
         LM_ERR("error parsing or no Contact hdr found!\n");
         goto error;
      }
   }

   /* extract from contact header the all the addresses */
   if (parse_contact( msg->contact )!=0) {
      LM_ERR("unable to parse Contact hdr!\n");
      goto error;
   }

   /* in contact hdr, in parsed attr, we should have a list of contacts */
   if ( msg->contact->parsed ) {
      contacts = ((struct contact_body*)msg->contact->parsed)->contacts;
      for( ; contacts ; contacts=contacts->next) {
         /* check if the contact is a valid sip uri */
         if (parse_uri( contacts->uri.s, contacts->uri.len , &uri)!=0) {
            continue;
         }
         /* convert the q param to int value (if any) */
         if (contacts->q) {
            if (parse_q( &(contacts->q->body), &prio )!=0)
               continue;
         } else {
            prio = 10; /* set default to minimum */
         }
         /* add the uri to location set */
         if (add_location(loc_set,&contacts->uri,0,prio,CPL_LOC_DUPL)!=0) {
            LM_ERR("unable to add <%.*s>\n",
               contacts->uri.len,contacts->uri.s);
         }
      }
   }

   return 0;
error:
   return -1;
}



static void reply_callback( struct cell* t, int type, struct tmcb_params* ps)
{
   struct cpl_interpreter *intr = (struct cpl_interpreter*)(*(ps->param));
   struct location        *loc  = 0;
   int rez;

   if (intr==0) {
      LM_WARN("param=0 for callback %d, transaction=%p \n",type,t);
      return;
   }

   if (type&TMCB_RESPONSE_OUT) {
      /* the purpose of the final reply is to trash down the interpreter
       * structure! it's the safest place to do that, since this callback
       * it's called only once per transaction for final codes (>=200) ;-) */
      if (ps->code>=200) {
         LM_DBG("code=%d, final reply received\n", ps->code);
         /* CPL interpretation done, call established -> destroy */
         free_cpl_interpreter( intr );
         /* set to zero the param callback*/
         *(ps->param) = 0;
      }
      return;
   } else if (!type&TMCB_ON_FAILURE) {
      LM_ERR("unknown type %d\n",type);
      goto exit;
   }

   LM_DBG("negativ reply received\n");

   intr->flags |= CPL_PROXY_DONE;
   intr->msg = ps->req;

   /* is the negative reply triggered by a cancel from UAC side? */
   if (was_cancelled(t)) {
      /* stop whole interpretation */
      return;
   }

   /* if it's a redirect-> do I have to added to the location set ? */
   if (intr->proxy.recurse && (ps->code)/100==3) {
      LM_DBG("recurse level %d processing..\n",intr->proxy.recurse);
      intr->proxy.recurse--;
      /* get the locations from the Contact */
      add_contacts_to_loc_set( ps->rpl, &(intr->loc_set));
      switch (intr->proxy.ordering) {
         case SEQUENTIAL_VAL:
            /* update the last_to_proxy to last location from set */
            if (intr->proxy.last_to_proxy==0) {
               /* the pointer went through entire old set -> set it to the
                * updated set, from the beginning  */
               if (intr->loc_set==0)
                  /* the updated set is also empty -> proxy ended */
                  break;
               intr->proxy.last_to_proxy = intr->loc_set;
            }
            while(intr->proxy.last_to_proxy->next)
               intr->proxy.last_to_proxy=intr->proxy.last_to_proxy->next;
            break;
         case PARALLEL_VAL:
            /* push the whole new location set to be proxy */
            intr->proxy.last_to_proxy = intr->loc_set;
            break;
         case FIRSTONLY_VAL:
            intr->proxy.last_to_proxy = 0;
            break;
      }
   }

   /* the current proxying failed -> do I have another location to try ?
    * This applies only for SERIAL forking or if RECURSE is set */
   if (intr->proxy.last_to_proxy && !(no_new_branches(t)) ) {
      /* continue proxying */
      LM_DBG("resuming proxying....\n");
      switch (intr->proxy.ordering) {
         case PARALLEL_VAL:
            /* I get here only if I got a 3xx and RECURSE in on ->
             * forward to all location from location set */
            intr->proxy.last_to_proxy = 0;
            cpl_proxy_to_loc_set(intr->msg,&(intr->loc_set),intr->flags );
            break;
         case SEQUENTIAL_VAL:
            /* place a new branch to the next location from loc. set*/
            loc = remove_first_location( &(intr->loc_set) );
            /*print_location_set(intr->loc_set);*/
            /* update (if necessary) the last_to_proxy location  */
            if (intr->proxy.last_to_proxy==loc)
               intr->proxy.last_to_proxy = 0;
            cpl_proxy_to_loc_set(intr->msg,&loc,intr->flags );
            break;
         default:
            LM_CRIT("unexpected ordering found "
               "when continuing proxying (%d)\n",intr->proxy.ordering);
            goto exit;
      }
      /* nothing more to be done */
      return;
   } else {
      /* done with proxying.... -> process the final response */
      LM_DBG("final_reply: got a final %d\n",ps->code);
      intr->ip = 0;
      if (ps->code==486 || ps->code==600) {
         /* busy response */
         intr->ip = intr->proxy.busy;
      } else if (ps->code==408) {
         /* request timeout -> no response */
         intr->ip = intr->proxy.noanswer;
      } else if (((ps->code)/100)==3) {
         /* redirection */
         /* add to the location list all the addresses from Contact */
         add_contacts_to_loc_set( ps->rpl, &(intr->loc_set));
         print_location_set( intr->loc_set );
         intr->ip = intr->proxy.redirect;
      } else {
         /* generic failure */
         intr->ip = intr->proxy.failure;
      }

      if (intr->ip==0)
         intr->ip = (intr->proxy.default_)?
            intr->proxy.default_:DEFAULT_ACTION;
      if (intr->ip!=DEFAULT_ACTION)
         intr->ip = get_first_child( intr->ip );

      if( intr->ip==DEFAULT_ACTION)
         rez = run_default(intr);
      else
         rez = cpl_run_script(intr);
      switch ( rez ) {
         case SCRIPT_END:
            /* we don't need to free the interpreter here since it will 
             * be freed in the final_reply callback */
         case SCRIPT_TO_BE_CONTINUED:
            return;
         case SCRIPT_RUN_ERROR:
         case SCRIPT_FORMAT_ERROR:
            goto exit;
         default:
            LM_CRIT("improper result %d\n",
               rez);
            goto exit;
      }
   }

exit:
   /* in case of error the default response chosen by ser at the last
    * proxying will be forwarded to the UAC */
   free_cpl_interpreter( intr );
   /* set to zero the param callback*/
   *(ps->param) = 0;
   return;
}



static inline char *run_proxy( struct cpl_interpreter *intr )
{
   unsigned short attr_name;
   unsigned short n;
   int_str is_val;
   char *kid;
   char *p;
   int i;
   str *s;
   struct location *loc;

   intr->proxy.ordering = PARALLEL_VAL;
   intr->proxy.recurse = (unsigned short)cpl_env.proxy_recurse;

   /* identify the attributes */
   for( i=NR_OF_ATTR(intr->ip),p=ATTR_PTR(intr->ip) ; i>0 ; i-- ) {
      get_basic_attr( p, attr_name, n, intr, script_error);
      switch (attr_name) {
         case TIMEOUT_ATTR:
            if (cpl_env.timer_avp.n || cpl_env.timer_avp.s.s) {
               is_val.n = n;
               if ( add_avp( cpl_env.timer_avp_type,
               cpl_env.timer_avp, is_val)<0) {
                  LM_ERR("unable to set timer AVP\n");
                  /* continue */
               }
            }
            break;
         case RECURSE_ATTR:
            switch (n) {
               case NO_VAL:
                  intr->proxy.recurse = 0;
                  break;
               case YES_VAL:
                  /* already set as default */
                  break;
               default:
                  LM_ERR("invalid value (%u) found"
                     " for attr. RECURSE in PROXY node!\n",n);
                  goto script_error;
            }
            break;
         case ORDERING_ATTR:
            if (n!=PARALLEL_VAL && n!=SEQUENTIAL_VAL && n!=FIRSTONLY_VAL){
               LM_ERR("invalid value (%u) found"
                  " for attr. ORDERING in PROXY node!\n",n);
               goto script_error;
            }
            intr->proxy.ordering = n;
            break;
         default:
            LM_ERR("unknown attribute (%d) in"
               "PROXY node\n",attr_name);
            goto script_error;
      }
   }

   intr->proxy.busy = intr->proxy.noanswer = 0;
   intr->proxy.redirect = intr->proxy.failure = intr->proxy.default_ = 0;

   /* this is quite an "expensive" node to run, so let's make some checking
    * before getting deeply into it */
   for( i=0 ; i<NR_OF_KIDS(intr->ip) ; i++ ) {
      kid = intr->ip + KID_OFFSET(intr->ip,i);
      check_overflow_by_ptr( kid+SIMPLE_NODE_SIZE(kid), intr, script_error);
      switch ( NODE_TYPE(kid) ) {
         case BUSY_NODE :
            intr->proxy.busy = kid;
            break;
         case NOANSWER_NODE:
            intr->proxy.noanswer = kid;
            break;
         case REDIRECTION_NODE:
            intr->proxy.redirect = kid;
            break;
         case FAILURE_NODE:
            intr->proxy.failure = kid;
            break;
         case DEFAULT_NODE:
            intr->proxy.default_ = kid;
            break;
         default:
            LM_ERR("unknown output node type"
               " (%d) for PROXY node\n",NODE_TYPE(kid));
            goto script_error;
      }
   }

   /* if the location set if empty, I will go directly on failure/default */
   if (intr->loc_set==0) {
      LM_DBG("location set found empty -> going on "
         "failure/default branch\n");
         if (intr->proxy.failure)
            return get_first_child(intr->proxy.failure);
         else if (intr->proxy.default_)
            return get_first_child(intr->proxy.default_);
         else return DEFAULT_ACTION;
   }

   /* if it's the first execution of a proxy node, force parsing of the needed
    * headers and duplicate them in shared memory */
   if (!(intr->flags&CPL_PROXY_DONE)) {
      /* user name is already in shared memory */
      /* requested URI - mandatory in SIP msg (cannot be STR_NOT_FOUND) */
      s = GET_RURI( intr->msg );
      duplicate_str( s , intr->ruri );
      intr->flags |= CPL_RURI_DUPLICATED;
      /* TO header - mandatory in SIP msg (cannot be STR_NOT_FOUND) */
      if (!intr->to) {
         if (!intr->msg->to &&
         (parse_headers(intr->msg,HDR_TO_F,0)==-1 || !intr->msg->to)) {
            LM_ERR("bad msg or missing TO header\n");
            goto runtime_error;
         }
         s = &(get_to(intr->msg)->uri);
      } else {
         s = intr->to;
      }
      duplicate_str( s , intr->to );
      intr->flags |= CPL_TO_DUPLICATED;
      /* FROM header - mandatory in SIP msg (cannot be STR_NOT_FOUND) */
      if (!intr->from) {
         if (parse_from_header( intr->msg )<0)
            goto runtime_error;
         s = &(get_from(intr->msg)->uri);
      } else {
         s = intr->from;
      }
      duplicate_str( s , intr->from );
      intr->flags |= CPL_FROM_DUPLICATED;
      /* SUBJECT header - optional in SIP msg (can be STR_NOT_FOUND) */
      if (intr->subject!=STR_NOT_FOUND) {
         search_and_duplicate_hdr(intr,subject,HDR_SUBJECT_F,s);
         if (intr->subject!=STR_NOT_FOUND)
            intr->flags |= CPL_SUBJECT_DUPLICATED;
      }
      /* ORGANIZATION header - optional in SIP msg (can be STR_NOT_FOUND) */
      if ( intr->organization!=STR_NOT_FOUND) {
         search_and_duplicate_hdr(intr,organization,HDR_ORGANIZATION_F,s);
         if ( intr->organization!=STR_NOT_FOUND)
            intr->flags |= CPL_ORGANIZATION_DUPLICATED;
      }
      /* USER_AGENT header - optional in SIP msg (can be STR_NOT_FOUND) */
      if (intr->user_agent!=STR_NOT_FOUND) {
         search_and_duplicate_hdr(intr,user_agent,HDR_USERAGENT_F,s);
         if (intr->user_agent!=STR_NOT_FOUND)
            intr->flags |= CPL_USERAGENT_DUPLICATED;
      }
      /* ACCEPT_LANGUAGE header - optional in SIP msg
       * (can be STR_NOT_FOUND) */
      if (intr->accept_language!=STR_NOT_FOUND) {
         search_and_duplicate_hdr(intr,accept_language,
            HDR_ACCEPTLANGUAGE_F,s);
         if (intr->accept_language!=STR_NOT_FOUND)
            intr->flags |= CPL_ACCEPTLANG_DUPLICATED;
      }
      /* PRIORITY header - optional in SIP msg (can be STR_NOT_FOUND) */
      if (intr->priority!=STR_NOT_FOUND) {
         search_and_duplicate_hdr(intr,priority,HDR_PRIORITY_F,s);
         if (intr->priority!=STR_NOT_FOUND)
            intr->flags |= CPL_PRIORITY_DUPLICATED;
      }

      /* now is the first time doing proxy, so I can still be stateless;
       * as proxy is done all the time stateful, I have to switch from
       * stateless to stateful if necessary.  */
      if ( !(intr->flags&CPL_IS_STATEFUL) ) {
         i = cpl_fct.tmb.t_newtran( intr->msg );
         if (i<0) {
            LM_ERR("failed to build new transaction!\n");
            goto runtime_error;
         } else if (i==0) {
            LM_ERR("processed INVITE is a retransmission!\n");
            /* instead of generating an error is better just to break the
             * script by returning EO_SCRIPT */
            return EO_SCRIPT;
         }
         intr->flags |= CPL_IS_STATEFUL;
      }

      /* as I am interested in getting the responses back - I need to install
       * some callback functions for replies  */
      if (cpl_fct.tmb.register_tmcb(intr->msg,0,
      TMCB_ON_FAILURE|TMCB_RESPONSE_OUT,reply_callback,(void*)intr,0) <= 0 ) {
         LM_ERR("failed to register TMCB_RESPONSE_OUT callback\n");
         goto runtime_error;
      }
   }

   switch (intr->proxy.ordering) {
      case FIRSTONLY_VAL:
         /* forward the request only to the first address from loc. set */
         /* location set cannot be empty -> was checked before */
         loc = remove_first_location( &(intr->loc_set) );
         intr->proxy.last_to_proxy = 0;
         /* set the new ip before proxy -> otherwise race cond with rpls */
         intr->ip = CPL_TO_CONTINUE;
         if (cpl_proxy_to_loc_set(intr->msg,&loc,intr->flags )==-1)
            goto runtime_error;
         break;
      case PARALLEL_VAL:
         /* forward to all location from location set */
         intr->proxy.last_to_proxy = 0;
         /* set the new ip before proxy -> otherwise race cond with rpls */
         intr->ip = CPL_TO_CONTINUE;
         if (cpl_proxy_to_loc_set(intr->msg,&(intr->loc_set),intr->flags)
         ==-1)
            goto runtime_error;
         break;
      case SEQUENTIAL_VAL:
         /* forward the request one at the time to all addresses from
          * loc. set; location set cannot be empty -> was checked before */
         /* use the first location from set */
         loc = remove_first_location( &(intr->loc_set) );
         /* set as the last_to_proxy the last location from set */
         intr->proxy.last_to_proxy = intr->loc_set;
         while (intr->proxy.last_to_proxy&&intr->proxy.last_to_proxy->next)
            intr->proxy.last_to_proxy = intr->proxy.last_to_proxy->next;
         /* set the new ip before proxy -> otherwise race cond with rpls */
         intr->ip = CPL_TO_CONTINUE;
         if (cpl_proxy_to_loc_set(intr->msg,&loc,intr->flags)==-1)
            goto runtime_error;
         break;
   }

   return CPL_TO_CONTINUE;
script_error:
   return CPL_SCRIPT_ERROR;
mem_error:
   LM_ERR("no more free shm memory\n");
runtime_error:
   return CPL_RUNTIME_ERROR;
}