| /* Shared library add-on to ip6tables to add Dst header support. */ |
| #include <stdbool.h> |
| #include <stdio.h> |
| #include <netdb.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <getopt.h> |
| #include <errno.h> |
| #include <xtables.h> |
| #include <linux/netfilter_ipv6/ip6t_opts.h> |
| #include <sys/types.h> |
| #include <sys/socket.h> |
| #include <arpa/inet.h> |
| |
| static void dst_help(void) |
| { |
| printf( |
| "dst match options:\n" |
| "[!] --dst-len length total length of this header\n" |
| " --dst-opts TYPE[:LEN][,TYPE[:LEN]...]\n" |
| " Options and its length (list, max: %d)\n", |
| IP6T_OPTS_OPTSNR); |
| } |
| |
| static const struct option dst_opts[] = { |
| {.name = "dst-len", .has_arg = true, .val = '1'}, |
| {.name = "dst-opts", .has_arg = true, .val = '2'}, |
| {.name = "dst-not-strict", .has_arg = true, .val = '3'}, |
| XT_GETOPT_TABLEEND, |
| }; |
| |
| static uint32_t |
| parse_opts_num(const char *idstr, const char *typestr) |
| { |
| unsigned long int id; |
| char* ep; |
| |
| id = strtoul(idstr, &ep, 0); |
| |
| if ( idstr == ep ) { |
| xtables_error(PARAMETER_PROBLEM, |
| "dst: no valid digits in %s `%s'", typestr, idstr); |
| } |
| if ( id == ULONG_MAX && errno == ERANGE ) { |
| xtables_error(PARAMETER_PROBLEM, |
| "%s `%s' specified too big: would overflow", |
| typestr, idstr); |
| } |
| if ( *idstr != '\0' && *ep != '\0' ) { |
| xtables_error(PARAMETER_PROBLEM, |
| "dst: error parsing %s `%s'", typestr, idstr); |
| } |
| return id; |
| } |
| |
| static int |
| parse_options(const char *optsstr, uint16_t *opts) |
| { |
| char *buffer, *cp, *next, *range; |
| unsigned int i; |
| |
| buffer = strdup(optsstr); |
| if (!buffer) |
| xtables_error(OTHER_PROBLEM, "strdup failed"); |
| |
| for (cp = buffer, i = 0; cp && i < IP6T_OPTS_OPTSNR; cp = next, i++) |
| { |
| next = strchr(cp, ','); |
| |
| if (next) |
| *next++='\0'; |
| |
| range = strchr(cp, ':'); |
| |
| if (range) { |
| if (i == IP6T_OPTS_OPTSNR-1) |
| xtables_error(PARAMETER_PROBLEM, |
| "too many ports specified"); |
| *range++ = '\0'; |
| } |
| |
| opts[i] = (parse_opts_num(cp, "opt") & 0xFF) << 8; |
| if (range) { |
| if (opts[i] == 0) |
| xtables_error(PARAMETER_PROBLEM, |
| "PAD0 hasn't got length"); |
| opts[i] |= parse_opts_num(range, "length") & 0xFF; |
| } else |
| opts[i] |= (0x00FF); |
| |
| #ifdef DEBUG |
| printf("opts str: %s %s\n", cp, range); |
| printf("opts opt: %04X\n", opts[i]); |
| #endif |
| } |
| |
| if (cp) |
| xtables_error(PARAMETER_PROBLEM, "too many addresses specified"); |
| |
| free(buffer); |
| |
| #ifdef DEBUG |
| printf("addr nr: %d\n", i); |
| #endif |
| |
| return i; |
| } |
| |
| static void dst_init(struct xt_entry_match *m) |
| { |
| struct ip6t_opts *optinfo = (struct ip6t_opts *)m->data; |
| |
| optinfo->hdrlen = 0; |
| optinfo->flags = 0; |
| optinfo->invflags = 0; |
| optinfo->optsnr = 0; |
| } |
| |
| static int dst_parse(int c, char **argv, int invert, unsigned int *flags, |
| const void *entry, struct xt_entry_match **match) |
| { |
| struct ip6t_opts *optinfo = (struct ip6t_opts *)(*match)->data; |
| |
| switch (c) { |
| case '1': |
| if (*flags & IP6T_OPTS_LEN) |
| xtables_error(PARAMETER_PROBLEM, |
| "Only one `--dst-len' allowed"); |
| xtables_check_inverse(optarg, &invert, &optind, 0, argv); |
| optinfo->hdrlen = parse_opts_num(optarg, "length"); |
| if (invert) |
| optinfo->invflags |= IP6T_OPTS_INV_LEN; |
| optinfo->flags |= IP6T_OPTS_LEN; |
| *flags |= IP6T_OPTS_LEN; |
| break; |
| case '2': |
| if (*flags & IP6T_OPTS_OPTS) |
| xtables_error(PARAMETER_PROBLEM, |
| "Only one `--dst-opts' allowed"); |
| xtables_check_inverse(optarg, &invert, &optind, 0, argv); |
| if (invert) |
| xtables_error(PARAMETER_PROBLEM, |
| " '!' not allowed with `--dst-opts'"); |
| optinfo->optsnr = parse_options(optarg, optinfo->opts); |
| optinfo->flags |= IP6T_OPTS_OPTS; |
| *flags |= IP6T_OPTS_OPTS; |
| break; |
| case '3': |
| if (*flags & IP6T_OPTS_NSTRICT) |
| xtables_error(PARAMETER_PROBLEM, |
| "Only one `--dst-not-strict' allowed"); |
| if ( !(*flags & IP6T_OPTS_OPTS) ) |
| xtables_error(PARAMETER_PROBLEM, |
| "`--dst-opts ...' required before " |
| "`--dst-not-strict'"); |
| optinfo->flags |= IP6T_OPTS_NSTRICT; |
| *flags |= IP6T_OPTS_NSTRICT; |
| break; |
| } |
| |
| return 1; |
| } |
| |
| static void |
| print_options(unsigned int optsnr, uint16_t *optsp) |
| { |
| unsigned int i; |
| |
| for(i = 0; i < optsnr; i++) { |
| printf("%d", (optsp[i] & 0xFF00) >> 8); |
| |
| if ((optsp[i] & 0x00FF) != 0x00FF) |
| printf(":%d", (optsp[i] & 0x00FF)); |
| |
| printf("%c", (i != optsnr - 1) ? ',' : ' '); |
| } |
| } |
| |
| static void dst_print(const void *ip, const struct xt_entry_match *match, |
| int numeric) |
| { |
| const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data; |
| |
| printf("dst "); |
| if (optinfo->flags & IP6T_OPTS_LEN) |
| printf("length:%s%u ", |
| optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "", |
| optinfo->hdrlen); |
| |
| if (optinfo->flags & IP6T_OPTS_OPTS) |
| printf("opts "); |
| |
| print_options(optinfo->optsnr, (uint16_t *)optinfo->opts); |
| |
| if (optinfo->flags & IP6T_OPTS_NSTRICT) |
| printf("not-strict "); |
| |
| if (optinfo->invflags & ~IP6T_OPTS_INV_MASK) |
| printf("Unknown invflags: 0x%X ", |
| optinfo->invflags & ~IP6T_OPTS_INV_MASK); |
| } |
| |
| static void dst_save(const void *ip, const struct xt_entry_match *match) |
| { |
| const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data; |
| |
| if (optinfo->flags & IP6T_OPTS_LEN) { |
| printf("%s--dst-len %u ", |
| (optinfo->invflags & IP6T_OPTS_INV_LEN) ? "! " : "", |
| optinfo->hdrlen); |
| } |
| |
| if (optinfo->flags & IP6T_OPTS_OPTS) |
| printf("--dst-opts "); |
| |
| print_options(optinfo->optsnr, (uint16_t *)optinfo->opts); |
| |
| if (optinfo->flags & IP6T_OPTS_NSTRICT) |
| printf("--dst-not-strict "); |
| } |
| |
| static struct xtables_match dst_mt6_reg = { |
| .name = "dst", |
| .version = XTABLES_VERSION, |
| .family = NFPROTO_IPV6, |
| .size = XT_ALIGN(sizeof(struct ip6t_opts)), |
| .userspacesize = XT_ALIGN(sizeof(struct ip6t_opts)), |
| .help = dst_help, |
| .init = dst_init, |
| .parse = dst_parse, |
| .print = dst_print, |
| .save = dst_save, |
| .extra_opts = dst_opts, |
| }; |
| |
| void |
| _init(void) |
| { |
| xtables_register_match(&dst_mt6_reg); |
| } |