bgpd/bgp_regex.c

   1 /* AS regular expression routine
   2  * Copyright (C) 1999 Kunihiro Ishiguro
   3  *
   4  * This file is part of GNU Zebra.
   5  *
   6  * GNU Zebra is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2, or (at your option) any
   9  * later version.
  10  *
  11  * GNU Zebra is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include <zebra.h>
  22
  23 #include "log.h"
  24 #include "command.h"
  25 #include "memory.h"
  26 #include "queue.h"
  27 #include "filter.h"
  28
  29 #include "bgpd.h"
  30 #include "bgp_aspath.h"
  31 #include "bgp_regex.h"
  32
  33 /* Character `_' has special mean.  It represents [,{}() ] and the
  34    beginning of the line(^) and the end of the line ($).
  35
  36    (^|[,{}() ]|$) */
  37
  38 regex_t *bgp_regcomp(const char *regstr)
  39 {
  40         /* Convert _ character to generic regular expression. */
  41         int i, j;
  42         int len;
  43         int magic = 0;
  44         char *magic_str;
  45         char magic_regexp[] = "(^|[,{}() ]|$)";
  46         int ret;
  47         regex_t *regex;
  48
  49         len = strlen(regstr);
  50         for (i = 0; i < len; i++)
  51                 if (regstr[i] == '_')
  52                         magic++;
  53
  54         magic_str = XMALLOC(MTYPE_TMP, len + (14 * magic) + 1);
  55
  56         for (i = 0, j = 0; i < len; i++) {
  57                 if (regstr[i] == '_') {
  58                         memcpy(magic_str + j, magic_regexp,
  59                                strlen(magic_regexp));
  60                         j += strlen(magic_regexp);
  61                 } else
  62                         magic_str[j++] = regstr[i];
  63         }
  64         magic_str[j] = '\0';
  65
  66         regex = XMALLOC(MTYPE_BGP_REGEXP, sizeof(regex_t));
  67
  68         ret = regcomp(regex, magic_str, REG_EXTENDED | REG_NOSUB);
  69
  70         XFREE(MTYPE_TMP, magic_str);
  71
  72         if (ret != 0) {
  73                 XFREE(MTYPE_BGP_REGEXP, regex);
  74                 return NULL;
  75         }
  76
  77         return regex;
  78 }
  79
  80 int bgp_regexec(regex_t *regex, struct aspath *aspath)
  81 {
  82         return regexec(regex, aspath->str, 0, NULL, 0);
  83 }
  84
  85 void bgp_regex_free(regex_t *regex)
  86 {
  87         regfree(regex);
  88         XFREE(MTYPE_BGP_REGEXP, regex);
  89 }