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

   1 /* Shared library add-on to iptables to add AH 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 <iptables.h>
   9 #include <linux/netfilter_ipv4/ipt_ah.h>
  10
  11 /* Function which prints out usage message. */
  12 static void
  13 help(void)
  14 {
  15         printf(
  16 "AH v%s options:\n"
  17 " --ahspi [!] spi[:spi]\n"
  18 "                               match spi (range)\n",
  19 IPTABLES_VERSION);
  20 }
  21
  22 static struct option opts[] = {
  23         { "ahspi", 1, 0, '1' },
  24         {0}
  25 };
  26
  27 static u_int32_t
  28 parse_ah_spi(const char *spistr)
  29 {
  30         unsigned long int spi;
  31         char* ep;
  32
  33         spi =  strtoul(spistr,&ep,0) ;
  34
  35         if ( spistr == ep ) {
  36                 exit_error(PARAMETER_PROBLEM,
  37                            "AH no valid digits in spi `%s'", spistr);
  38         }
  39         if ( spi == ULONG_MAX  && errno == ERANGE ) {
  40                 exit_error(PARAMETER_PROBLEM,
  41                            "spi `%s' specified too big: would overflow", spistr);
  42         }
  43         if ( *spistr != '\0'  && *ep != '\0' ) {
  44                 exit_error(PARAMETER_PROBLEM,
  45                            "AH error parsing spi `%s'", spistr);
  46         }
  47         return (u_int32_t) spi;
  48 }
  49
  50 static void
  51 parse_ah_spis(const char *spistring, u_int32_t *spis)
  52 {
  53         char *buffer;
  54         char *cp;
  55
  56         buffer = strdup(spistring);
  57         if ((cp = strchr(buffer, ':')) == NULL)
  58                 spis[0] = spis[1] = parse_ah_spi(buffer);
  59         else {
  60                 *cp = '\0';
  61                 cp++;
  62
  63                 spis[0] = buffer[0] ? parse_ah_spi(buffer) : 0;
  64                 spis[1] = cp[0] ? parse_ah_spi(cp) : 0xFFFFFFFF;
  65         }
  66         free(buffer);
  67 }
  68
  69 /* Initialize the match. */
  70 static void
  71 init(struct ipt_entry_match *m, unsigned int *nfcache)
  72 {
  73         struct ipt_ah *ahinfo = (struct ipt_ah *)m->data;
  74
  75         ahinfo->spis[1] = 0xFFFFFFFF;
  76 }
  77
  78 #define AH_SPI 0x01
  79
  80 /* Function which parses command options; returns true if it
  81    ate an option */
  82 static int
  83 parse(int c, char **argv, int invert, unsigned int *flags,
  84       const struct ipt_entry *entry,
  85       unsigned int *nfcache,
  86       struct ipt_entry_match **match)
  87 {
  88         struct ipt_ah *ahinfo = (struct ipt_ah *)(*match)->data;
  89
  90         switch (c) {
  91         case '1':
  92                 if (*flags & AH_SPI)
  93                         exit_error(PARAMETER_PROBLEM,
  94                                    "Only one `--ahspi' allowed");
  95                 check_inverse(optarg, &invert, &optind, 0);
  96                 parse_ah_spis(argv[optind-1], ahinfo->spis);
  97                 if (invert)
  98                         ahinfo->invflags |= IPT_AH_INV_SPI;
  99                 *flags |= AH_SPI;
 100                 break;
 101         default:
 102                 return 0;
 103         }
 104
 105         return 1;
 106 }
 107
 108 /* Final check; we don't care. */
 109 static void
 110 final_check(unsigned int flags)
 111 {
 112 }
 113
 114 static void
 115 print_spis(const char *name, u_int32_t min, u_int32_t max,
 116             int invert)
 117 {
 118         const char *inv = invert ? "!" : "";
 119
 120         if (min != 0 || max != 0xFFFFFFFF || invert) {
 121                 printf("%s", name);
 122                 if (min == max) {
 123                         printf(":%s", inv);
 124                         printf("%u", min);
 125                 } else {
 126                         printf("s:%s", inv);
 127                         printf("%u",min);
 128                         printf(":");
 129                         printf("%u",max);
 130                 }
 131                 printf(" ");
 132         }
 133 }
 134
 135 /* Prints out the union ipt_matchinfo. */
 136 static void
 137 print(const struct ipt_ip *ip,
 138       const struct ipt_entry_match *match, int numeric)
 139 {
 140         const struct ipt_ah *ah = (struct ipt_ah *)match->data;
 141
 142         printf("ah ");
 143         print_spis("spi", ah->spis[0], ah->spis[1],
 144                     ah->invflags & IPT_AH_INV_SPI);
 145         if (ah->invflags & ~IPT_AH_INV_MASK)
 146                 printf("Unknown invflags: 0x%X ",
 147                        ah->invflags & ~IPT_AH_INV_MASK);
 148 }
 149
 150 /* Saves the union ipt_matchinfo in parsable form to stdout. */
 151 static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
 152 {
 153         const struct ipt_ah *ahinfo = (struct ipt_ah *)match->data;
 154
 155         if (!(ahinfo->spis[0] == 0
 156             && ahinfo->spis[1] == 0xFFFFFFFF)) {
 157                 printf("--ahspi %s",
 158                         (ahinfo->invflags & IPT_AH_INV_SPI) ? "! " : "");
 159                 if (ahinfo->spis[0]
 160                     != ahinfo->spis[1])
 161                         printf("%u:%u ",
 162                                ahinfo->spis[0],
 163                                ahinfo->spis[1]);
 164                 else
 165                         printf("%u ",
 166                                ahinfo->spis[0]);
 167         }
 168
 169 }
 170
 171 static struct iptables_match ah = {
 172         .next           = NULL,
 173         .name           = "ah",
 174         .version        = IPTABLES_VERSION,
 175         .size           = IPT_ALIGN(sizeof(struct ipt_ah)),
 176         .userspacesize  = IPT_ALIGN(sizeof(struct ipt_ah)),
 177         .help           = &help,
 178         .init           = &init,
 179         .parse          = &parse,
 180         .final_check    = &final_check,
 181         .print          = &print,
 182         .save           = &save,
 183         .extra_opts     = opts
 184 };
 185
 186 void
 187 _init(void)
 188 {
 189         register_match(&ah);
 190 }