bgpd/bgp_regex.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* AS regular expression routine
   3  * Copyright (C) 1999 Kunihiro Ishiguro
   4  */
   5
   6 #include <zebra.h>
   7
   8 #include "log.h"
   9 #include "command.h"
  10 #include "memory.h"
  11 #include "queue.h"
  12 #include "filter.h"
  13
  14 #include "bgpd.h"
  15 #include "bgp_aspath.h"
  16 #include "bgp_regex.h"
  17
  18 /* Character `_' has special mean.  It represents [,{}() ] and the
  19    beginning of the line(^) and the end of the line ($).
  20
  21    (^|[,{}() ]|$) */
  22
  23 regex_t *bgp_regcomp(const char *regstr)
  24 {
  25         /* Convert _ character to generic regular expression. */
  26         int i, j;
  27         int len;
  28         int magic = 0;
  29         char *magic_str;
  30         char magic_regexp[] = "(^|[,{}() ]|$)";
  31         int ret;
  32         regex_t *regex;
  33
  34         len = strlen(regstr);
  35         for (i = 0; i < len; i++)
  36                 if (regstr[i] == '_')
  37                         magic++;
  38
  39         magic_str = XMALLOC(MTYPE_TMP, len + (14 * magic) + 1);
  40
  41         for (i = 0, j = 0; i < len; i++) {
  42                 if (regstr[i] == '_') {
  43                         memcpy(magic_str + j, magic_regexp,
  44                                strlen(magic_regexp));
  45                         j += strlen(magic_regexp);
  46                 } else
  47                         magic_str[j++] = regstr[i];
  48         }
  49         magic_str[j] = '\0';
  50
  51         regex = XMALLOC(MTYPE_BGP_REGEXP, sizeof(regex_t));
  52
  53         ret = regcomp(regex, magic_str, REG_EXTENDED | REG_NOSUB);
  54
  55         XFREE(MTYPE_TMP, magic_str);
  56
  57         if (ret != 0) {
  58                 XFREE(MTYPE_BGP_REGEXP, regex);
  59                 return NULL;
  60         }
  61
  62         return regex;
  63 }
  64
  65 int bgp_regexec(regex_t *regex, struct aspath *aspath)
  66 {
  67         return regexec(regex, aspath->str, 0, NULL, 0);
  68 }
  69
  70 void bgp_regex_free(regex_t *regex)
  71 {
  72         regfree(regex);
  73         XFREE(MTYPE_BGP_REGEXP, regex);
  74 }