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 *
  39 bgp_regcomp (const char *regstr)
  40 {
  41   /* Convert _ character to generic regular expression. */
  42   int i, j;
  43   int len;
  44   int magic = 0;
  45   char *magic_str;
  46   char magic_regexp[] = "(^|[,{}() ]|$)";
  47   int ret;
  48   regex_t *regex;
  49
  50   len = strlen (regstr);
  51   for (i = 0; i < len; i++)
  52     if (regstr[i] == '_')
  53       magic++;
  54
  55   magic_str = XMALLOC (MTYPE_TMP, len + (14 * magic) + 1);
  56
  57   for (i = 0, j = 0; i < len; i++)
  58     {
  59       if (regstr[i] == '_')
  60         {
  61           memcpy (magic_str + j, magic_regexp, strlen (magic_regexp));
  62           j += strlen (magic_regexp);
  63         }
  64       else
  65         magic_str[j++] = regstr[i];
  66     }
  67   magic_str[j] = '\0';
  68
  69   regex = XMALLOC (MTYPE_BGP_REGEXP, sizeof (regex_t));
  70
  71   ret = regcomp (regex, magic_str, REG_EXTENDED|REG_NOSUB);
  72
  73   XFREE (MTYPE_TMP, magic_str);
  74
  75   if (ret != 0)
  76     {
  77       XFREE (MTYPE_BGP_REGEXP, regex);
  78       return NULL;
  79     }
  80
  81   return regex;
  82 }
  83
  84 int
  85 bgp_regexec (regex_t *regex, struct aspath *aspath)
  86 {
  87   return regexec (regex, aspath->str, 0, NULL, 0);
  88 }
  89
  90 void
  91 bgp_regex_free (regex_t *regex)
  92 {
  93   regfree (regex);
  94   XFREE (MTYPE_BGP_REGEXP, regex);
  95 }