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
  17 along with GNU Zebra; see the file COPYING.  If not, write to the Free
  18 Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  19 02111-1307, USA.  */
  20
  21 #include <zebra.h>
  22
  23 #include "log.h"
  24 #include "command.h"
  25 #include "memory.h"
  26
  27 #include "bgpd.h"
  28 #include "bgp_aspath.h"
  29 #include "bgp_regex.h"
  30
  31 /* Character `_' has special mean.  It represents [,{}() ] and the
  32    beginning of the line(^) and the end of the line ($).
  33
  34    (^|[,{}() ]|$) */
  35
  36 regex_t *
  37 bgp_regcomp (const char *regstr)
  38 {
  39   /* Convert _ character to generic regular expression. */
  40   int i, j;
  41   int len;
  42   int magic = 0;
  43   char *magic_str;
  44   char magic_regexp[] = "(^|[,{}() ]|$)";
  45   int ret;
  46   regex_t *regex;
  47
  48   len = strlen (regstr);
  49   for (i = 0; i < len; i++)
  50     if (regstr[i] == '_')
  51       magic++;
  52
  53   magic_str = XMALLOC (MTYPE_TMP, len + (14 * magic) + 1);
  54
  55   for (i = 0, j = 0; i < len; i++)
  56     {
  57       if (regstr[i] == '_')
  58         {
  59           memcpy (magic_str + j, magic_regexp, strlen (magic_regexp));
  60           j += strlen (magic_regexp);
  61         }
  62       else
  63         magic_str[j++] = regstr[i];
  64     }
  65   magic_str[j] = '\0';
  66
  67   regex = XMALLOC (MTYPE_BGP_REGEXP, sizeof (regex_t));
  68
  69   ret = regcomp (regex, magic_str, REG_EXTENDED|REG_NOSUB);
  70
  71   XFREE (MTYPE_TMP, magic_str);
  72
  73   if (ret != 0)
  74     {
  75       XFREE (MTYPE_BGP_REGEXP, regex);
  76       return NULL;
  77     }
  78
  79   return regex;
  80 }
  81
  82 int
  83 bgp_regexec (regex_t *regex, struct aspath *aspath)
  84 {
  85   return regexec (regex, aspath->str, 0, NULL, 0);
  86 }
  87
  88 void
  89 bgp_regex_free (regex_t *regex)
  90 {
  91   regfree (regex);
  92   XFREE (MTYPE_BGP_REGEXP, regex);
  93 }