diff options
Diffstat (limited to 'extensions/libip6t_dst.c')
| -rw-r--r-- | extensions/libip6t_dst.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/extensions/libip6t_dst.c b/extensions/libip6t_dst.c new file mode 100644 index 0000000..72df6ad --- /dev/null +++ b/extensions/libip6t_dst.c @@ -0,0 +1,241 @@ +/* Shared library add-on to ip6tables to add Dst header support. */ +#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 = 1, .val = '1' }, + { .name = "dst-opts", .has_arg = 1, .val = '2' }, + { .name = "dst-not-strict", .has_arg = 1, .val = '3' }, + { .name = NULL } +}; + +static u_int32_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, u_int16_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; + default: + return 0; + } + + return 1; +} + +static void +print_options(unsigned int optsnr, u_int16_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, (u_int16_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, (u_int16_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); +} |