ip6tables-save.c

   1 /* Code to save the ip6tables state, in human readable-form. */
   2 /* Author:  Andras Kis-Szabo <kisza@sch.bme.hu>
   3  * Original code: iptables-save
   4  * Authors: Paul 'Rusty' Russel <rusty@linuxcare.com.au> and
   5  *          Harald Welte <laforge@gnumonks.org>
   6  * This code is distributed under the terms of GNU GPL v2
   7  */
   8 #include <getopt.h>
   9 #include <sys/errno.h>
  10 #include <stdio.h>
  11 #include <fcntl.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14 #include <dlfcn.h>
  15 #include <time.h>
  16 #include <netdb.h>
  17 #include <arpa/inet.h>
  18 #include "libiptc/libip6tc.h"
  19 #include "ip6tables.h"
  20
  21 static int binary = 0, counters = 0;
  22
  23 static struct option options[] = {
  24         { "binary", 0, 0, 'b' },
  25         { "counters", 0, 0, 'c' },
  26         { "dump", 0, 0, 'd' },
  27         { "table", 1, 0, 't' },
  28         { 0 }
  29 };
  30
  31
  32 /* This assumes that mask is contiguous, and byte-bounded. */
  33 static void
  34 print_iface(char letter, const char *iface, const unsigned char *mask,
  35             int invert)
  36 {
  37         unsigned int i;
  38
  39         if (mask[0] == 0)
  40                 return;
  41
  42         printf("-%c %s", letter, invert ? "! " : "");
  43
  44         for (i = 0; i < IFNAMSIZ; i++) {
  45                 if (mask[i] != 0) {
  46                         if (iface[i] != '\0')
  47                                 printf("%c", iface[i]);
  48                 } else {
  49                         /* we can access iface[i-1] here, because
  50                          * a few lines above we make sure that mask[0] != 0 */
  51                         if (iface[i-1] != '\0')
  52                                 printf("+");
  53                         break;
  54                 }
  55         }
  56
  57         printf(" ");
  58 }
  59
  60 /* These are hardcoded backups in ip6tables.c, so they are safe */
  61 struct pprot {
  62         char *name;
  63         u_int8_t num;
  64 };
  65
  66 static const struct pprot chain_protos[] = {
  67         { "tcp", IPPROTO_TCP },
  68         { "udp", IPPROTO_UDP },
  69         { "icmpv6", IPPROTO_ICMPV6 },
  70         { "esp", IPPROTO_ESP },
  71         { "ah", IPPROTO_AH },
  72 };
  73
  74 /* The ip6tables looks up the /etc/protocols. */
  75 static void print_proto(u_int16_t proto, int invert)
  76 {
  77         if (proto) {
  78                 unsigned int i;
  79                 const char *invertstr = invert ? "! " : "";
  80
  81                 struct protoent *pent = getprotobynumber(proto);
  82                 if (pent) {
  83                         printf("-p %s%s ",
  84                                invertstr, pent->p_name);
  85                         return;
  86                 }
  87
  88                 for (i = 0; i < sizeof(chain_protos)/sizeof(struct pprot); i++)
  89                         if (chain_protos[i].num == proto) {
  90                                 printf("-p %s%s ",
  91                                        invertstr, chain_protos[i].name);
  92                                 return;
  93                         }
  94
  95                 printf("-p %s%u ", invertstr, proto);
  96         }
  97 }
  98
  99 static int print_match(const struct ip6t_entry_match *e,
 100                         const struct ip6t_ip6 *ip)
 101 {
 102         struct ip6tables_match *match
 103                 = find_match(e->u.user.name, TRY_LOAD, NULL);
 104
 105         if (match) {
 106                 printf("-m %s ", e->u.user.name);
 107
 108                 /* some matches don't provide a save function */
 109                 if (match->save)
 110                         match->save(ip, e);
 111         } else {
 112                 if (e->u.match_size) {
 113                         fprintf(stderr,
 114                                 "Can't find library for match `%s'\n",
 115                                 e->u.user.name);
 116                         exit(1);
 117                 }
 118         }
 119         return 0;
 120 }
 121
 122 /* print a given ip including mask if neccessary */
 123 static void print_ip(char *prefix, const struct in6_addr *ip, const struct in6_addr *mask, int invert)
 124 {
 125         char buf[51];
 126         int l = ipv6_prefix_length(mask);
 127
 128         if (!mask && !ip)
 129                 return;
 130
 131         printf("%s %s%s",
 132                 prefix,
 133                 invert ? "! " : "",
 134                 inet_ntop(AF_INET6, ip, buf, sizeof buf));
 135
 136         if (l == -1)
 137                 printf("/%s ", inet_ntop(AF_INET6, mask, buf, sizeof buf));
 138         else
 139                 printf("/%d ", l);
 140 }
 141
 142 /* We want this to be readable, so only print out neccessary fields.
 143  * Because that's the kind of world I want to live in.  */
 144 static void print_rule(const struct ip6t_entry *e,
 145                 ip6tc_handle_t *h, const char *chain, int counters)
 146 {
 147         struct ip6t_entry_target *t;
 148         const char *target_name;
 149
 150         /* print counters */
 151         if (counters)
 152                 printf("[%llu:%llu] ", (unsigned long long)e->counters.pcnt, (unsigned long long)e->counters.bcnt);
 153
 154         /* print chain name */
 155         printf("-A %s ", chain);
 156
 157         /* Print IP part. */
 158         print_ip("-s", &(e->ipv6.src), &(e->ipv6.smsk),
 159                         e->ipv6.invflags & IP6T_INV_SRCIP);
 160
 161         print_ip("-d", &(e->ipv6.dst), &(e->ipv6.dmsk),
 162                         e->ipv6.invflags & IP6T_INV_DSTIP);
 163
 164         print_iface('i', e->ipv6.iniface, e->ipv6.iniface_mask,
 165                     e->ipv6.invflags & IP6T_INV_VIA_IN);
 166
 167         print_iface('o', e->ipv6.outiface, e->ipv6.outiface_mask,
 168                     e->ipv6.invflags & IP6T_INV_VIA_OUT);
 169
 170         print_proto(e->ipv6.proto, e->ipv6.invflags & IP6T_INV_PROTO);
 171
 172 #if 0
 173         /* not definied in ipv6
 174          * FIXME: linux/netfilter_ipv6/ip6_tables: IP6T_INV_FRAG why definied? */
 175         if (e->ipv6.flags & IPT_F_FRAG)
 176                 printf("%s-f ",
 177                        e->ipv6.invflags & IP6T_INV_FRAG ? "! " : "");
 178 #endif
 179
 180         if (e->ipv6.flags & IP6T_F_TOS)
 181                 printf("%s-? %d ",
 182                        e->ipv6.invflags & IP6T_INV_TOS ? "! " : "",
 183                        e->ipv6.tos);
 184
 185         /* Print matchinfo part */
 186         if (e->target_offset) {
 187                 IP6T_MATCH_ITERATE(e, print_match, &e->ipv6);
 188         }
 189
 190         /* Print target name */
 191         target_name = ip6tc_get_target(e, h);
 192         if (target_name && (*target_name != '\0'))
 193                 printf("-j %s ", target_name);
 194
 195         /* Print targinfo part */
 196         t = ip6t_get_target((struct ip6t_entry *)e);
 197         if (t->u.user.name[0]) {
 198                 struct ip6tables_target *target
 199                         = find_target(t->u.user.name, TRY_LOAD);
 200
 201                 if (!target) {
 202                         fprintf(stderr, "Can't find library for target `%s'\n",
 203                                 t->u.user.name);
 204                         exit(1);
 205                 }
 206
 207                 if (target->save)
 208                         target->save(&e->ipv6, t);
 209                 else {
 210                         /* If the target size is greater than ip6t_entry_target
 211                          * there is something to be saved, we just don't know
 212                          * how to print it */
 213                         if (t->u.target_size !=
 214                             sizeof(struct ip6t_entry_target)) {
 215                                 fprintf(stderr, "Target `%s' is missing "
 216                                                 "save function\n",
 217                                         t->u.user.name);
 218                                 exit(1);
 219                         }
 220                 }
 221         }
 222         printf("\n");
 223 }
 224
 225 /* Debugging prototype. */
 226 static int for_each_table(int (*func)(const char *tablename))
 227 {
 228         int ret = 1;
 229         FILE *procfile = NULL;
 230         char tablename[IP6T_TABLE_MAXNAMELEN+1];
 231
 232         procfile = fopen("/proc/net/ip6_tables_names", "r");
 233         if (!procfile)
 234                 return 0;
 235
 236         while (fgets(tablename, sizeof(tablename), procfile)) {
 237                 if (tablename[strlen(tablename) - 1] != '\n')
 238                         exit_error(OTHER_PROBLEM,
 239                                    "Badly formed tablename `%s'\n",
 240                                    tablename);
 241                 tablename[strlen(tablename) - 1] = '\0';
 242                 ret &= func(tablename);
 243         }
 244
 245         return ret;
 246 }
 247
 248
 249 static int do_output(const char *tablename)
 250 {
 251         ip6tc_handle_t h;
 252         const char *chain = NULL;
 253
 254         if (!tablename)
 255                 return for_each_table(&do_output);
 256
 257         h = ip6tc_init(tablename);
 258         if (!h)
 259                 exit_error(OTHER_PROBLEM, "Can't initialize: %s\n",
 260                            ip6tc_strerror(errno));
 261
 262         if (!binary) {
 263                 time_t now = time(NULL);
 264
 265                 printf("# Generated by ip6tables-save v%s on %s",
 266                        IPTABLES_VERSION, ctime(&now));
 267                 printf("*%s\n", tablename);
 268
 269                 /* Dump out chain names first,
 270                  * thereby preventing dependency conflicts */
 271                 for (chain = ip6tc_first_chain(&h);
 272                      chain;
 273                      chain = ip6tc_next_chain(&h)) {
 274
 275                         printf(":%s ", chain);
 276                         if (ip6tc_builtin(chain, h)) {
 277                                 struct ip6t_counters count;
 278                                 printf("%s ",
 279                                        ip6tc_get_policy(chain, &count, &h));
 280                                 printf("[%llu:%llu]\n", (unsigned long long)count.pcnt, (unsigned long long)count.bcnt);
 281                         } else {
 282                                 printf("- [0:0]\n");
 283                         }
 284                 }
 285
 286
 287                 for (chain = ip6tc_first_chain(&h);
 288                      chain;
 289                      chain = ip6tc_next_chain(&h)) {
 290                         const struct ip6t_entry *e;
 291
 292                         /* Dump out rules */
 293                         e = ip6tc_first_rule(chain, &h);
 294                         while(e) {
 295                                 print_rule(e, &h, chain, counters);
 296                                 e = ip6tc_next_rule(e, &h);
 297                         }
 298                 }
 299
 300                 now = time(NULL);
 301                 printf("COMMIT\n");
 302                 printf("# Completed on %s", ctime(&now));
 303         } else {
 304                 /* Binary, huh?  OK. */
 305                 exit_error(OTHER_PROBLEM, "Binary NYI\n");
 306         }
 307
 308         ip6tc_free(&h);
 309
 310         return 1;
 311 }
 312
 313 /* Format:
 314  * :Chain name POLICY packets bytes
 315  * rule
 316  */
 317 int main(int argc, char *argv[])
 318 {
 319         const char *tablename = NULL;
 320         int c;
 321
 322         program_name = "ip6tables-save";
 323         program_version = IPTABLES_VERSION;
 324
 325         lib_dir = getenv("IP6TABLES_LIB_DIR");
 326         if (!lib_dir)
 327                 lib_dir = IP6T_LIB_DIR;
 328
 329 #ifdef NO_SHARED_LIBS
 330         init_extensions();
 331 #endif
 332
 333         while ((c = getopt_long(argc, argv, "bcdt:", options, NULL)) != -1) {
 334                 switch (c) {
 335                 case 'b':
 336                         binary = 1;
 337                         break;
 338
 339                 case 'c':
 340                         counters = 1;
 341                         break;
 342
 343                 case 't':
 344                         /* Select specific table. */
 345                         tablename = optarg;
 346                         break;
 347                 case 'd':
 348                         do_output(tablename);
 349                         exit(0);
 350                 }
 351         }
 352
 353         if (optind < argc) {
 354                 fprintf(stderr, "Unknown arguments found on commandline");
 355                 exit(1);
 356         }
 357
 358         return !do_output(tablename);
 359 }