extensions/libip6t_NFLOG.c

   1 #include <stdlib.h>
   2 #include <stdio.h>
   3 #include <string.h>
   4 #include <getopt.h>
   5 #include <ip6tables.h>
   6
   7 #include <linux/netfilter_ipv6/ip6_tables.h>
   8 #include <linux/netfilter/xt_NFLOG.h>
   9
  10 enum {
  11         NFLOG_GROUP     = 0x1,
  12         NFLOG_PREFIX    = 0x2,
  13         NFLOG_RANGE     = 0x4,
  14         NFLOG_THRESHOLD = 0x8,
  15 };
  16
  17 static struct option opts[] = {
  18         { "nflog-group",     1, 0, NFLOG_GROUP },
  19         { "nflog-prefix",    1, 0, NFLOG_PREFIX },
  20         { "nflog-range",     1, 0, NFLOG_RANGE },
  21         { "nflog-threshold", 1, 0, NFLOG_THRESHOLD },
  22 };
  23
  24 static void help(void)
  25 {
  26         printf("NFLOG v%s options:\n"
  27                " --nflog-group NUM              NETLINK group used for logging\n"
  28                " --nflog-range NUM              Number of byte to copy\n"
  29                " --nflog-threshold NUM          Message threshold of in-kernel queue\n"
  30                " --nflog-prefix STRING          Prefix string for log messages\n\n",
  31                IPTABLES_VERSION);
  32 }
  33
  34 static void init(struct ip6t_entry_target *t, unsigned int *nfcache)
  35 {
  36         struct xt_nflog_info *info = (struct xt_nflog_info *)t->data;
  37
  38         info->group     = 0;
  39         info->threshold = XT_NFLOG_DEFAULT_THRESHOLD;
  40 }
  41
  42 static int parse(int c, char **argv, int invert, unsigned int *flags,
  43                  const struct ip6t_entry *entry,
  44                  struct xt_entry_target **target)
  45 {
  46         struct xt_nflog_info *info = (struct xt_nflog_info *)(*target)->data;
  47         int n;
  48
  49         switch (c) {
  50         case NFLOG_GROUP:
  51                 if (*flags & NFLOG_GROUP)
  52                         exit_error(PARAMETER_PROBLEM,
  53                                    "Can't specify --nflog-group twice");
  54                 if (check_inverse(optarg, &invert, NULL, 0))
  55                         exit_error(PARAMETER_PROBLEM,
  56                                    "Unexpected `!' after --nflog-group");
  57
  58                 n = atoi(optarg);
  59                 if (n < 0)
  60                         exit_error(PARAMETER_PROBLEM,
  61                                    "--nflog-group can not be negative");
  62                 info->group = n;
  63                 break;
  64         case NFLOG_PREFIX:
  65                 if (*flags & NFLOG_PREFIX)
  66                         exit_error(PARAMETER_PROBLEM,
  67                                    "Can't specify --nflog-prefix twice");
  68                 if (check_inverse(optarg, &invert, NULL, 0))
  69                         exit_error(PARAMETER_PROBLEM,
  70                                    "Unexpected `!' after --nflog-prefix");
  71
  72                 n = strlen(optarg);
  73                 if (n == 0)
  74                         exit_error(PARAMETER_PROBLEM,
  75                                    "No prefix specified for --nflog-prefix");
  76                 if (n >= sizeof(info->prefix))
  77                         exit_error(PARAMETER_PROBLEM,
  78                                    "--nflog-prefix too long, max %Zu characters",
  79                                    sizeof(info->prefix) - 1);
  80                 if (n != strlen(strtok(optarg, "\n")))
  81                         exit_error(PARAMETER_PROBLEM,
  82                                    "Newlines are not allowed in --nflog-prefix");
  83                 strcpy(info->prefix, optarg);
  84                 break;
  85         case NFLOG_RANGE:
  86                 if (*flags & NFLOG_RANGE)
  87                         exit_error(PARAMETER_PROBLEM,
  88                                    "Can't specify --nflog-range twice");
  89                 n = atoi(optarg);
  90                 if (n < 0)
  91                         exit_error(PARAMETER_PROBLEM,
  92                                    "Invalid --nflog-range, must be >= 0");
  93                 info->len = n;
  94                 break;
  95         case NFLOG_THRESHOLD:
  96                 if (*flags & NFLOG_THRESHOLD)
  97                         exit_error(PARAMETER_PROBLEM,
  98                                    "Can't specify --nflog-threshold twice");
  99                 n = atoi(optarg);
 100                 if (n < 1)
 101                         exit_error(PARAMETER_PROBLEM,
 102                                    "Invalid --nflog-threshold, must be >= 1");
 103                 info->threshold = n;
 104                 break;
 105         default:
 106                 return 0;
 107         }
 108         *flags |= c;
 109         return 1;
 110 }
 111
 112 static void final_check(unsigned int flags)
 113 {
 114         return;
 115 }
 116
 117 static void nflog_print(const struct xt_nflog_info *info, char *prefix)
 118 {
 119         if (info->prefix[0] != '\0')
 120                 printf("%snflog-prefix \"%s\" ", prefix, info->prefix);
 121         if (info->group)
 122                 printf("%snflog-group %u ", prefix, info->group);
 123         if (info->len)
 124                 printf("%snflog-range %u ", prefix, info->len);
 125         if (info->threshold != XT_NFLOG_DEFAULT_THRESHOLD)
 126                 printf("%snflog-threshold %u ", prefix, info->threshold);
 127 }
 128
 129 static void print(const struct ip6t_ip6 *ip, const struct xt_entry_target *target,
 130                   int numeric)
 131 {
 132         const struct xt_nflog_info *info = (struct xt_nflog_info *)target->data;
 133
 134         nflog_print(info, "");
 135 }
 136
 137 static void save(const struct ip6t_ip6 *ip, const struct xt_entry_target *target)
 138 {
 139         const struct xt_nflog_info *info = (struct xt_nflog_info *)target->data;
 140
 141         nflog_print(info, "--");
 142 }
 143
 144 static struct ip6tables_target nflog = {
 145         .name           = "NFLOG",
 146         .version        = IPTABLES_VERSION,
 147         .size           = XT_ALIGN(sizeof(struct xt_nflog_info)),
 148         .userspacesize  = XT_ALIGN(sizeof(struct xt_nflog_info)),
 149         .help           = help,
 150         .init           = init,
 151         .parse          = parse,
 152         .final_check    = final_check,
 153         .print          = print,
 154         .save           = save,
 155         .extra_opts     = opts,
 156 };
 157
 158 void _init(void)
 159 {
 160         register_target6(&nflog);
 161 }