release/src/router/iptables/extensions/libipt_comment.c

   1 /* Shared library add-on to iptables to add comment match support.
   2  *
   3  * ChangeLog
   4  *     2003-05-13: Brad Fisher <brad@info-link.net>
   5  *         Initial comment match
   6  *     2004-05-12: Brad Fisher <brad@info-link.net>
   7  *         Port to patch-o-matic-ng
   8  */
   9 #include <stdio.h>
  10 #include <string.h>
  11 #include <stdlib.h>
  12 #include <getopt.h>
  13
  14 #include <iptables.h>
  15 #include <linux/netfilter_ipv4/ipt_comment.h>
  16
  17 /* Function which prints out usage message. */
  18 static void
  19 help(void)
  20 {
  21         printf(
  22                 "COMMENT match options:\n"
  23                 "--comment COMMENT             Attach a comment to a rule\n\n"
  24                 );
  25 }
  26
  27 static struct option opts[] = {
  28         { "comment", 1, 0, '1' },
  29         {0}
  30 };
  31
  32 static void
  33 parse_comment(const char *s, struct ipt_comment_info *info)
  34 {
  35         int slen = strlen(s);
  36
  37         if (slen >= IPT_MAX_COMMENT_LEN) {
  38                 exit_error(PARAMETER_PROBLEM,
  39                         "COMMENT must be shorter than %i characters", IPT_MAX_COMMENT_LEN);
  40         }
  41         strcpy((char *)info->comment, s);
  42 }
  43
  44 /* Function which parses command options; returns true if it
  45    ate an option */
  46 static int
  47 parse(int c, char **argv, int invert, unsigned int *flags,
  48       const struct ipt_entry *entry,
  49       unsigned int *nfcache,
  50       struct ipt_entry_match **match)
  51 {
  52         struct ipt_comment_info *commentinfo = (struct ipt_comment_info *)(*match)->data;
  53
  54         switch (c) {
  55         case '1':
  56                 check_inverse(argv[optind-1], &invert, &optind, 0);
  57                 if (invert) {
  58                         exit_error(PARAMETER_PROBLEM,
  59                                         "Sorry, you can't have an inverted comment");
  60                 }
  61                 parse_comment(argv[optind-1], commentinfo);
  62                 *flags = 1;
  63                 break;
  64
  65         default:
  66                 return 0;
  67         }
  68         return 1;
  69 }
  70
  71 /* Final check; must have specified --comment. */
  72 static void
  73 final_check(unsigned int flags)
  74 {
  75         if (!flags)
  76                 exit_error(PARAMETER_PROBLEM,
  77                            "COMMENT match: You must specify `--comment'");
  78 }
  79
  80 /* Prints out the matchinfo. */
  81 static void
  82 print(const struct ipt_ip *ip,
  83       const struct ipt_entry_match *match,
  84       int numeric)
  85 {
  86         struct ipt_comment_info *commentinfo = (struct ipt_comment_info *)match->data;
  87
  88         commentinfo->comment[IPT_MAX_COMMENT_LEN-1] = '\0';
  89         printf("/* %s */ ", commentinfo->comment);
  90 }
  91
  92 /* Saves the union ipt_matchinfo in parsable form to stdout. */
  93 static void
  94 save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
  95 {
  96         struct ipt_comment_info *commentinfo = (struct ipt_comment_info *)match->data;
  97
  98         commentinfo->comment[IPT_MAX_COMMENT_LEN-1] = '\0';
  99         printf("--comment \"%s\" ", commentinfo->comment);
 100 }
 101
 102 static struct iptables_match comment = {
 103     .next               = NULL,
 104     .name               = "comment",
 105     .version            = IPTABLES_VERSION,
 106     .size               = IPT_ALIGN(sizeof(struct ipt_comment_info)),
 107     .userspacesize      = IPT_ALIGN(sizeof(struct ipt_comment_info)),
 108     .help               = &help,
 109     .parse              = &parse,
 110     .final_check        = &final_check,
 111     .print              = &print,
 112     .save               = &save,
 113     .extra_opts         = opts
 114 };
 115
 116 void _init(void)
 117 {
 118         register_match(&comment);
 119 }