redirect.c

/*
 * $Id$
 *
 * Copyright (C) 2005 Voice Sistem SRL
 *
 * 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:
 * ---------
 *  2005-06-22  first version (bogdan)
 */

#include <sys/types.h> /* for regex */
#include <regex.h>

#include "../../sr_module.h"
#include "../../str.h"
#include "../../dprint.h"
#include "../../mem/mem.h"
#include "../../modules/tm/tm_load.h"
#include "rd_funcs.h"
#include "rd_filter.h"

MODULE_VERSION

/* internal global variables */
struct tm_binds rd_tmb;           /*imported functions from tm */
cmd_function    rd_acc_fct = 0;   /*imported function from acc */

/* global parameter variables */
char *acc_db_table = "acc";
char *acc_fct_s    = "acc_log_request";

/* private parameter variables */
char *deny_filter_s = 0;
char *accept_filter_s = 0;
char *def_filter_s = 0;

unsigned int bflags = 0;

#define ACCEPT_RULE_STR "accept"
#define DENY_RULE_STR   "deny"



static int redirect_init(void);
static int w_set_deny(struct sip_msg* msg, char *dir, char *foo);
static int w_set_accept(struct sip_msg* msg, char *dir, char *foo);
static int w_get_redirect1(struct sip_msg* msg, char *dir, char *foo);
static int w_get_redirect2(struct sip_msg* msg, char *dir, char *foo);
static int regexp_compile(char *re_s, regex_t **re);
static int get_redirect_fixup(void** param, int param_no);
static int setf_fixup(void** param, int param_no);


static cmd_export_t cmds[] = {
        {"set_deny_filter",   (cmd_function)w_set_deny,      2,  setf_fixup, 0,
                        FAILURE_ROUTE },
        {"set_accept_filter", (cmd_function)w_set_accept,    2,  setf_fixup, 0,
                        FAILURE_ROUTE },
        {"get_redirects",     (cmd_function)w_get_redirect2,  2,  get_redirect_fixup, 0,
                        FAILURE_ROUTE },
        {"get_redirects",     (cmd_function)w_get_redirect1,  1,  get_redirect_fixup, 0,
                        FAILURE_ROUTE },
        {0, 0, 0, 0, 0, 0}
};

static param_export_t params[] = {
        {"deny_filter",     STR_PARAM,  &deny_filter_s    },
        {"accept_filter",   STR_PARAM,  &accept_filter_s  },
        {"default_filter",  STR_PARAM,  &def_filter_s     },
        {"acc_function",    STR_PARAM,  &acc_fct_s        },
        {"acc_db_table",    STR_PARAM,  &acc_db_table     },
        {"bflags",              INT_PARAM,  &bflags                       },
        {0, 0, 0}
};


struct module_exports exports = {
        "uac_redirect",
        DEFAULT_DLFLAGS, /* dlopen flags */
        cmds,     /* Exported functions */
        params,   /* Exported parameters */
        0,        /* exported statistics */
        0,        /* exported MI functions */
        0,        /* exported pseudo-variables */
        0,        /* extra processes */
        redirect_init, /* Module initialization function */
        0,
        0,
        (child_init_function) 0 /* per-child init function */
};



int get_nr_max(char *s, unsigned char *max)
{
        unsigned short nr;
        int err;

        if ( s[0]=='*' && s[1]==0 ) {
                /* is '*' -> infinit ;-) */
                *max = 0;
                return 0;
        } else {
                /* must be a positive number less than 255 */
                nr = str2s(s, strlen(s), &err);
                if (err==0){
                        if (nr>255){
                                LM_ERR("number too big <%d> (max=255)\n",nr);
                                return -1;
                        }
                        *max = (unsigned char)nr;
                        return 0;
                }else{
                        LM_ERR("bad  number <%s>\n",s);
                        return -1;
                }
        }
}


static int get_redirect_fixup(void** param, int param_no)
{
        unsigned char maxb,maxt;
        struct acc_param *accp;
        cmd_function fct;
        char *p;
        char *s;

        s = (char*)*param;
        if (param_no==1) {
                if ( (p=strchr(s,':'))!=0 ) {
                        /* have max branch also */
                        *p = 0;
                        if (get_nr_max(p+1, &maxb)!=0)
                                return E_UNSPEC;
                } else {
                        maxb = 0; /* infinit */
                }

                /* get max total */
                if (get_nr_max(s, &maxt)!=0)
                        return E_UNSPEC;

                pkg_free(*param);
                *param=(void*)(long)( (((unsigned short)maxt)<<8) | maxb);

        } else if (param_no==2) {
                /* acc function loaded? */
                if (rd_acc_fct!=0)
                        return 0;
                /* must import the acc stuff */
                if (acc_fct_s==0 || acc_fct_s[0]==0) {
                        LM_ERR("acc support enabled, but no acc function defined\n");
                        return E_UNSPEC;
                }
                fct = find_export(acc_fct_s, 2, REQUEST_ROUTE);
                if ( fct==0 )
                        fct = find_export(acc_fct_s, 1, REQUEST_ROUTE);
                if ( fct==0 ) {
                        LM_ERR("cannot import %s function; is acc loaded and proper "
                                "compiled?\n", acc_fct_s);
                        return E_UNSPEC;
                }
                rd_acc_fct = fct;
                /* set the reason str */
                accp = (struct acc_param*)pkg_malloc(sizeof(struct acc_param));
                if (accp==0) {
                        LM_ERR("no more pkg mem\n");
                        return E_UNSPEC;
                }
                memset( accp, 0, sizeof(struct acc_param));
                if (s!=0 && *s!=0) {
                        accp->reason.s = s;
                        accp->reason.len = strlen(s);
                } else {
                        accp->reason.s = "n/a";
                        accp->reason.len = 3;
                }
                *param=(void*)accp;
        }

        return 0;
}


static int setf_fixup(void** param, int param_no)
{
        unsigned short nr;
        regex_t *filter;
        char *s;

        s = (char*)*param;
        if (param_no==1) {
                /* compile the filter */
                if (regexp_compile( s, &filter)<0) {
                        LM_ERR("cannot init filter <%s>\n", s);
                        return E_BAD_RE;
                }
                pkg_free(*param);
                *param = (void*)filter;
        } else if (param_no==2) {
                if (s==0 || s[0]==0) {
                        nr = 0;
                } else if (strcasecmp(s,"reset_all")==0) {
                        nr = RESET_ADDED|RESET_DEFAULT;
                } else if (strcasecmp(s,"reset_default")==0) {
                        nr = RESET_DEFAULT;
                } else if (strcasecmp(s,"reset_added")==0) {
                        nr = RESET_ADDED;
                } else {
                        LM_ERR("unknown reset type <%s>\n",s);
                        return E_UNSPEC;
                }
                pkg_free(*param);
                *param = (void*)(long)nr;
        }

        return 0;
}



static int regexp_compile(char *re_s, regex_t **re)
{
        *re = 0;
        if (re_s==0 || strlen(re_s)==0 ) {
                return 0;
        } else {
                if ((*re=pkg_malloc(sizeof(regex_t)))==0)
                        return E_OUT_OF_MEM;
                if (regcomp(*re, re_s, REG_EXTENDED|REG_ICASE|REG_NEWLINE) ){
                        pkg_free(*re);
                        *re = 0;
                        LM_ERR("regexp_compile:bad regexp <%s>\n", re_s);
                        return E_BAD_RE;
                }
        }
        return 0;
}



static int redirect_init(void)
{
        regex_t *filter;

        /* load the TM API */
        if (load_tm_api(&rd_tmb)!=0) {
                LM_ERR("failed to load TM API\n");
                goto error;
        }

        /* init filter */
        init_filters();

        /* what's the default rule? */
        if (def_filter_s) {
                if ( !strcasecmp(def_filter_s,ACCEPT_RULE_STR) ) {
                        set_default_rule( ACCEPT_RULE );
                } else if ( !strcasecmp(def_filter_s,DENY_RULE_STR) ) {
                        set_default_rule( DENY_RULE );
                } else {
                        LM_ERR("unknown default filter <%s>\n",def_filter_s);
                }
        }

        /* if accept filter specify, compile it */
        if (regexp_compile(accept_filter_s, &filter)<0) {
                LM_ERR("failed to init accept filter\n");
                goto error;
        }
        add_default_filter( ACCEPT_FILTER, filter);

        /* if deny filter specify, compile it */
        if (regexp_compile(deny_filter_s, &filter)<0) {
                LM_ERR("failed to init deny filter\n");
                goto error;
        }
        add_default_filter( DENY_FILTER, filter);

        return 0;
error:
        return -1;
}


static inline void msg_tracer(struct sip_msg* msg, int reset)
{
        static unsigned int id  = 0;
        static unsigned int set = 0;

        if (reset) {
                set = 0;
        } else {
                if (set) {
                        if (id!=msg->id) {
                                LM_WARN("filters set but not used -> reseting to default\n");
                                reset_filters();
                                id = msg->id;
                        }
                } else {
                        id = msg->id;
                        set = 1;
                }
        }
}


static int w_set_deny(struct sip_msg* msg, char *re, char *flags)
{
        msg_tracer( msg, 0);
        return (add_filter( DENY_FILTER, (regex_t*)re, (int)(long)flags)==0)?1:-1;
}


static int w_set_accept(struct sip_msg* msg, char *re, char *flags)
{
        msg_tracer( msg, 0);
        return (add_filter( ACCEPT_FILTER, (regex_t*)re, (int)(long)flags)==0)?1:-1;
}


static int w_get_redirect2(struct sip_msg* msg, char *max_c, char *reason)
{
        int n;
        unsigned short max;

        msg_tracer( msg, 0);
        /* get the contacts */
        max = (unsigned short)(long)max_c;
        n = get_redirect(msg , (max>>8)&0xff, max&0xff, (struct acc_param*)reason, bflags);
        reset_filters();
        /* reset the tracer */
        msg_tracer( msg, 1);

        return n;
}


static int w_get_redirect1(struct sip_msg* msg, char *max_c, char *foo)
{
        return w_get_redirect2(msg, max_c, 0);
}