release/src/router/iptables/extensions/libip6t_esp.c

   1 /* Shared library add-on to ip6tables to add ESP support. */
   2 #include <stdio.h>
   3 #include <netdb.h>
   4 #include <string.h>
   5 #include <stdlib.h>
   6 #include <getopt.h>
   7 #include <errno.h>
   8 #include <ip6tables.h>
   9 #include <linux/netfilter_ipv6/ip6t_esp.h>
  10
  11 /* Function which prints out usage message. */
  12 static void
  13 help(void)
  14 {
  15         printf(
  16 "ESP v%s options:\n"
  17 " --espspi [!] spi[:spi]        match spi (range)\n",
  18 IPTABLES_VERSION);
  19 }
  20
  21 static struct option opts[] = {
  22         { .name = "espspi", .has_arg = 1, .flag = 0, .val = '1' },
  23         { .name = 0 }
  24 };
  25
  26 static u_int32_t
  27 parse_esp_spi(const char *spistr)
  28 {
  29         unsigned long int spi;
  30         char* ep;
  31
  32         spi = strtoul(spistr, &ep, 0);
  33
  34         if ( spistr == ep ) {
  35                 exit_error(PARAMETER_PROBLEM,
  36                            "ESP no valid digits in spi `%s'", spistr);
  37         }
  38         if ( spi == ULONG_MAX  && errno == ERANGE ) {
  39                 exit_error(PARAMETER_PROBLEM,
  40                            "spi `%s' specified too big: would overflow", spistr);
  41         }
  42         if ( *spistr != '\0'  && *ep != '\0' ) {
  43                 exit_error(PARAMETER_PROBLEM,
  44                            "ESP error parsing spi `%s'", spistr);
  45         }
  46         return (u_int32_t) spi;
  47 }
  48
  49 static void
  50 parse_esp_spis(const char *spistring, u_int32_t *spis)
  51 {
  52         char *buffer;
  53         char *cp;
  54
  55         buffer = strdup(spistring);
  56         if ((cp = strchr(buffer, ':')) == NULL)
  57                 spis[0] = spis[1] = parse_esp_spi(buffer);
  58         else {
  59                 *cp = '\0';
  60                 cp++;
  61
  62                 spis[0] = buffer[0] ? parse_esp_spi(buffer) : 0;
  63                 spis[1] = cp[0] ? parse_esp_spi(cp) : 0xFFFFFFFF;
  64                 if (spis[0] > spis[1])
  65                         exit_error(PARAMETER_PROBLEM,
  66                                    "Invalid ESP spi range: %s", spistring);
  67         }
  68         free(buffer);
  69 }
  70
  71 /* Initialize the match. */
  72 static void
  73 init(struct ip6t_entry_match *m, unsigned int *nfcache)
  74 {
  75         struct ip6t_esp *espinfo = (struct ip6t_esp *)m->data;
  76
  77         espinfo->spis[1] = 0xFFFFFFFF;
  78 }
  79
  80 #define ESP_SPI 0x01
  81
  82 /* Function which parses command options; returns true if it
  83    ate an option */
  84 static int
  85 parse(int c, char **argv, int invert, unsigned int *flags,
  86       const struct ip6t_entry *entry,
  87       unsigned int *nfcache,
  88       struct ip6t_entry_match **match)
  89 {
  90         struct ip6t_esp *espinfo = (struct ip6t_esp *)(*match)->data;
  91
  92         switch (c) {
  93         case '1':
  94                 if (*flags & ESP_SPI)
  95                         exit_error(PARAMETER_PROBLEM,
  96                                    "Only one `--espspi' allowed");
  97                 check_inverse(optarg, &invert, &optind, 0);
  98                 parse_esp_spis(argv[optind-1], espinfo->spis);
  99                 if (invert)
 100                         espinfo->invflags |= IP6T_ESP_INV_SPI;
 101                 *flags |= ESP_SPI;
 102                 break;
 103         default:
 104                 return 0;
 105         }
 106
 107         return 1;
 108 }
 109
 110 /* Final check; we don't care. */
 111 static void
 112 final_check(unsigned int flags)
 113 {
 114 }
 115
 116 static void
 117 print_spis(const char *name, u_int32_t min, u_int32_t max,
 118             int invert)
 119 {
 120         const char *inv = invert ? "!" : "";
 121
 122         if (min != 0 || max != 0xFFFFFFFF || invert) {
 123                 if (min == max)
 124                         printf("%s:%s%u ", name, inv, min);
 125                 else
 126                         printf("%ss:%s%u:%u ", name, inv, min, max);
 127         }
 128 }
 129
 130 /* Prints out the union ip6t_matchinfo. */
 131 static void
 132 print(const struct ip6t_ip6 *ip,
 133       const struct ip6t_entry_match *match, int numeric)
 134 {
 135         const struct ip6t_esp *esp = (struct ip6t_esp *)match->data;
 136
 137         printf("esp ");
 138         print_spis("spi", esp->spis[0], esp->spis[1],
 139                     esp->invflags & IP6T_ESP_INV_SPI);
 140         if (esp->invflags & ~IP6T_ESP_INV_MASK)
 141                 printf("Unknown invflags: 0x%X ",
 142                        esp->invflags & ~IP6T_ESP_INV_MASK);
 143 }
 144
 145 /* Saves the union ip6t_matchinfo in parsable form to stdout. */
 146 static void save(const struct ip6t_ip6 *ip, const struct ip6t_entry_match *match)
 147 {
 148         const struct ip6t_esp *espinfo = (struct ip6t_esp *)match->data;
 149
 150         if (!(espinfo->spis[0] == 0
 151             && espinfo->spis[1] == 0xFFFFFFFF)) {
 152                 printf("--espspi %s",
 153                         (espinfo->invflags & IP6T_ESP_INV_SPI) ? "! " : "");
 154                 if (espinfo->spis[0]
 155                     != espinfo->spis[1])
 156                         printf("%u:%u ",
 157                                espinfo->spis[0],
 158                                espinfo->spis[1]);
 159                 else
 160                         printf("%u ",
 161                                espinfo->spis[0]);
 162         }
 163
 164 }
 165
 166 static
 167 struct ip6tables_match esp = {
 168         .name          = "esp",
 169         .version       = IPTABLES_VERSION,
 170         .size          = IP6T_ALIGN(sizeof(struct ip6t_esp)),
 171         .userspacesize = IP6T_ALIGN(sizeof(struct ip6t_esp)),
 172         .help          = &help,
 173         .init          = &init,
 174         .parse         = &parse,
 175         .final_check   = &final_check,
 176         .print         = &print,
 177         .save          = &save,
 178         .extra_opts    = opts
 179 };
 180
 181 void
 182 _init(void)
 183 {
 184         register_match6(&esp);
 185 }