callid.c

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/*
 * Copyright (C) 2001-2003 FhG Fokus
 *
 * This file is part of SIP-router, a free SIP server.
 *
 * SIP-router 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
 *
 * SIP-router 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:
 * ----------
 *  2003-04-09  Created by janakj
 *  2003-10-24  updated to the new socket_info lists (andrei)
 */

#include <stdio.h>
#include <stdlib.h>
#include "../../dprint.h"
#include "../../pt.h"
#include "../../socket_info.h"
#include "callid.h"

#define CALLID_NR_LEN 20

#define CALLID_SUFFIX_LEN ( 1 /* - */                                            + \
                            5 /* pid */                                          + \
                           42 /* embedded v4inv6 address can be looong '128.' */ + \
                            2 /* parenthesis [] */                               + \
                            1 /* ZT 0 */                                         + \
                           16 /* one never knows ;-) */                            \
                          )


static unsigned long callid_nr;
static char callid_buf[CALLID_NR_LEN + CALLID_SUFFIX_LEN];

static str callid_prefix;
static str callid_suffix;


int init_callid(void)
{
        int rand_bits, i;

             /* calculate the initial call-id */
             /* how many bits and chars do we need to display the 
              * whole ULONG number */
        callid_prefix.len = sizeof(unsigned long) * 2;
        callid_prefix.s = callid_buf;

        if (callid_prefix.len > CALLID_NR_LEN) {
                LOG(L_ERR, "ERROR: Too small callid buffer\n");
                return -1;
        }
        
        for(rand_bits = 1, i = RAND_MAX; i; i >>= 1, rand_bits++);  /* how long are the rand()s ? */
        i = callid_prefix.len * 4 / rand_bits; /* how many rands() fit in the ULONG ? */

             /* now fill in the callid with as many random
              * numbers as you can + 1 */
        callid_nr = rand(); /* this is the + 1 */

        while(i--) {
                callid_nr <<= rand_bits;
                callid_nr |= rand();
        }

        i = snprintf(callid_prefix.s, callid_prefix.len + 1, "%0*lx", callid_prefix.len, callid_nr);
        if ((i == -1) || (i > callid_prefix.len)) {
                LOG(L_CRIT, "BUG: SORRY, callid calculation failed\n");
                return -2;
        }
        
        DBG("Call-ID initialization: '%.*s'\n", callid_prefix.len, callid_prefix.s);
        return 0;
}


int child_init_callid(int rank) 
{
        struct socket_info *si;
        
        /* on tcp/tls bind_address is 0 so try to get the first address we listen
         * on no matter the protocol */
        si=bind_address?bind_address:get_first_socket();
        if (si==0){
                LOG(L_CRIT, "BUG: child_init_callid: null socket list\n");
                return -1;
        }
        callid_suffix.s = callid_buf + callid_prefix.len;

        callid_suffix.len = snprintf(callid_suffix.s, CALLID_SUFFIX_LEN,
                                     "%c%d@%.*s", '-', my_pid(), 
                                     si->address_str.len,
                                     si->address_str.s);
        if ((callid_suffix.len == -1) || (callid_suffix.len > CALLID_SUFFIX_LEN)) {
                LOG(L_ERR, "ERROR: child_init_callid: buffer too small\n");
                return -1;
        }

        DBG("DEBUG: callid: '%.*s'\n", callid_prefix.len + callid_suffix.len, callid_prefix.s);
        return 0;
}


static inline int inc_hexchar(char* _c)
{
        if (*_c == '9') {
                *_c = 'a';
                return 0;
        }

        if (*_c == 'f') {
                *_c = '0';
                return 1;
        }

        (*_c)++;
        return 0;
}


void generate_callid(str* callid)
{
        int i;

        for(i = callid_prefix.len; i; i--) {
                if (!inc_hexchar(callid_prefix.s + i - 1)) break;
        }
        callid->s = callid_prefix.s;
        callid->len = callid_prefix.len + callid_suffix.len;
}