extensions/libxt_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 <xtables.h>
  15 #include <linux/netfilter/xt_comment.h>
  16
  17 /* Function which prints out usage message. */
  18 static void comment_help(void)
  19 {
  20         printf(
  21                 "comment match options:\n"
  22                 "--comment COMMENT             Attach a comment to a rule\n");
  23 }
  24
  25 static const struct option comment_opts[] = {
  26         { "comment", 1, NULL, '1' },
  27         { .name = NULL }
  28 };
  29
  30 static void
  31 parse_comment(const char *s, struct xt_comment_info *info)
  32 {
  33         int slen = strlen(s);
  34
  35         if (slen >= XT_MAX_COMMENT_LEN) {
  36                 exit_error(PARAMETER_PROBLEM,
  37                         "COMMENT must be shorter than %i characters", XT_MAX_COMMENT_LEN);
  38         }
  39         strcpy((char *)info->comment, s);
  40 }
  41
  42 /* Function which parses command options; returns true if it
  43    ate an option */
  44 static int
  45 comment_parse(int c, char **argv, int invert, unsigned int *flags,
  46               const void *entry, struct xt_entry_match **match)
  47 {
  48         struct xt_comment_info *commentinfo = (struct xt_comment_info *)(*match)->data;
  49
  50         switch (c) {
  51         case '1':
  52                 check_inverse(argv[optind-1], &invert, &optind, 0);
  53                 if (invert) {
  54                         exit_error(PARAMETER_PROBLEM,
  55                                         "Sorry, you can't have an inverted comment");
  56                 }
  57                 parse_comment(argv[optind-1], commentinfo);
  58                 *flags = 1;
  59                 break;
  60
  61         default:
  62                 return 0;
  63         }
  64         return 1;
  65 }
  66
  67 /* Final check; must have specified --comment. */
  68 static void comment_check(unsigned int flags)
  69 {
  70         if (!flags)
  71                 exit_error(PARAMETER_PROBLEM,
  72                            "COMMENT match: You must specify `--comment'");
  73 }
  74
  75 /* Prints out the matchinfo. */
  76 static void
  77 comment_print(const void *ip, const struct xt_entry_match *match, int numeric)
  78 {
  79         struct xt_comment_info *commentinfo = (struct xt_comment_info *)match->data;
  80
  81         commentinfo->comment[XT_MAX_COMMENT_LEN-1] = '\0';
  82         printf("/* %s */ ", commentinfo->comment);
  83 }
  84
  85 /* Saves the union ipt_matchinfo in parsable form to stdout. */
  86 static void
  87 comment_save(const void *ip, const struct xt_entry_match *match)
  88 {
  89         struct xt_comment_info *commentinfo = (struct xt_comment_info *)match->data;
  90
  91         commentinfo->comment[XT_MAX_COMMENT_LEN-1] = '\0';
  92         printf("--comment \"%s\" ", commentinfo->comment);
  93 }
  94
  95 static struct xtables_match comment_match = {
  96         .family         = AF_INET,
  97         .name           = "comment",
  98         .version        = XTABLES_VERSION,
  99         .size           = XT_ALIGN(sizeof(struct xt_comment_info)),
 100         .userspacesize  = XT_ALIGN(sizeof(struct xt_comment_info)),
 101         .help           = comment_help,
 102         .parse          = comment_parse,
 103         .final_check    = comment_check,
 104         .print          = comment_print,
 105         .save           = comment_save,
 106         .extra_opts     = comment_opts,
 107 };
 108
 109 static struct xtables_match comment_match6 = {
 110         .family         = AF_INET6,
 111         .name           = "comment",
 112         .version        = XTABLES_VERSION,
 113         .size           = XT_ALIGN(sizeof(struct xt_comment_info)),
 114         .userspacesize  = XT_ALIGN(sizeof(struct xt_comment_info)),
 115         .help           = comment_help,
 116         .parse          = comment_parse,
 117         .final_check    = comment_check,
 118         .print          = comment_print,
 119         .save           = comment_save,
 120         .extra_opts     = comment_opts,
 121 };
 122
 123 void _init(void)
 124 {
 125         xtables_register_match(&comment_match);
 126         xtables_register_match(&comment_match6);
 127 }