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- #include <stdio.h>
- #include <xtables.h>
- #include <linux/netfilter_ipv6/ip6t_frag.h>
- enum {
- O_FRAGID = 0,
- O_FRAGLEN,
- O_FRAGRES,
- O_FRAGFIRST,
- O_FRAGMORE,
- O_FRAGLAST,
- F_FRAGMORE = 1 << O_FRAGMORE,
- F_FRAGLAST = 1 << O_FRAGLAST,
- };
- static void frag_help(void)
- {
- printf(
- "frag match options:\n"
- "[!] --fragid id[:id] match the id (range)\n"
- "[!] --fraglen length total length of this header\n"
- " --fragres check the reserved field too\n"
- " --fragfirst matches on the first fragment\n"
- " [--fragmore|--fraglast] there are more fragments or this\n"
- " is the last one\n");
- }
- #define s struct ip6t_frag
- static const struct xt_option_entry frag_opts[] = {
- {.name = "fragid", .id = O_FRAGID, .type = XTTYPE_UINT32RC,
- .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, ids)},
- {.name = "fraglen", .id = O_FRAGLEN, .type = XTTYPE_UINT32,
- .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, hdrlen)},
- {.name = "fragres", .id = O_FRAGRES, .type = XTTYPE_NONE},
- {.name = "fragfirst", .id = O_FRAGFIRST, .type = XTTYPE_NONE},
- {.name = "fragmore", .id = O_FRAGMORE, .type = XTTYPE_NONE,
- .excl = F_FRAGLAST},
- {.name = "fraglast", .id = O_FRAGLAST, .type = XTTYPE_NONE,
- .excl = F_FRAGMORE},
- XTOPT_TABLEEND,
- };
- #undef s
- static void frag_init(struct xt_entry_match *m)
- {
- struct ip6t_frag *fraginfo = (void *)m->data;
- fraginfo->ids[1] = ~0U;
- }
- static void frag_parse(struct xt_option_call *cb)
- {
- struct ip6t_frag *fraginfo = cb->data;
- xtables_option_parse(cb);
- switch (cb->entry->id) {
- case O_FRAGID:
- if (cb->nvals == 1)
- fraginfo->ids[1] = fraginfo->ids[0];
- if (cb->invert)
- fraginfo->invflags |= IP6T_FRAG_INV_IDS;
- /*
- * Note however that IP6T_FRAG_IDS is not tested by anything,
- * so it is merely here for completeness.
- */
- fraginfo->flags |= IP6T_FRAG_IDS;
- break;
- case O_FRAGLEN:
- /*
- * As of Linux 3.0, the kernel does not check for
- * fraglen at all.
- */
- if (cb->invert)
- fraginfo->invflags |= IP6T_FRAG_INV_LEN;
- fraginfo->flags |= IP6T_FRAG_LEN;
- break;
- case O_FRAGRES:
- fraginfo->flags |= IP6T_FRAG_RES;
- break;
- case O_FRAGFIRST:
- fraginfo->flags |= IP6T_FRAG_FST;
- break;
- case O_FRAGMORE:
- fraginfo->flags |= IP6T_FRAG_MF;
- break;
- case O_FRAGLAST:
- fraginfo->flags |= IP6T_FRAG_NMF;
- break;
- }
- }
- static void
- print_ids(const char *name, uint32_t min, uint32_t max,
- int invert)
- {
- const char *inv = invert ? "!" : "";
- if (min != 0 || max != 0xFFFFFFFF || invert) {
- printf("%s", name);
- if (min == max)
- printf(":%s%u", inv, min);
- else
- printf("s:%s%u:%u", inv, min, max);
- }
- }
- static void frag_print(const void *ip, const struct xt_entry_match *match,
- int numeric)
- {
- const struct ip6t_frag *frag = (struct ip6t_frag *)match->data;
- printf(" frag ");
- print_ids("id", frag->ids[0], frag->ids[1],
- frag->invflags & IP6T_FRAG_INV_IDS);
- if (frag->flags & IP6T_FRAG_LEN) {
- printf(" length:%s%u",
- frag->invflags & IP6T_FRAG_INV_LEN ? "!" : "",
- frag->hdrlen);
- }
- if (frag->flags & IP6T_FRAG_RES)
- printf(" reserved");
- if (frag->flags & IP6T_FRAG_FST)
- printf(" first");
- if (frag->flags & IP6T_FRAG_MF)
- printf(" more");
- if (frag->flags & IP6T_FRAG_NMF)
- printf(" last");
- if (frag->invflags & ~IP6T_FRAG_INV_MASK)
- printf(" Unknown invflags: 0x%X",
- frag->invflags & ~IP6T_FRAG_INV_MASK);
- }
- static void frag_save(const void *ip, const struct xt_entry_match *match)
- {
- const struct ip6t_frag *fraginfo = (struct ip6t_frag *)match->data;
- if (!(fraginfo->ids[0] == 0
- && fraginfo->ids[1] == 0xFFFFFFFF)) {
- printf("%s --fragid ",
- (fraginfo->invflags & IP6T_FRAG_INV_IDS) ? " !" : "");
- if (fraginfo->ids[0]
- != fraginfo->ids[1])
- printf("%u:%u",
- fraginfo->ids[0],
- fraginfo->ids[1]);
- else
- printf("%u",
- fraginfo->ids[0]);
- }
- if (fraginfo->flags & IP6T_FRAG_LEN) {
- printf("%s --fraglen %u",
- (fraginfo->invflags & IP6T_FRAG_INV_LEN) ? " !" : "",
- fraginfo->hdrlen);
- }
- if (fraginfo->flags & IP6T_FRAG_RES)
- printf(" --fragres");
- if (fraginfo->flags & IP6T_FRAG_FST)
- printf(" --fragfirst");
- if (fraginfo->flags & IP6T_FRAG_MF)
- printf(" --fragmore");
- if (fraginfo->flags & IP6T_FRAG_NMF)
- printf(" --fraglast");
- }
- static struct xtables_match frag_mt6_reg = {
- .name = "frag",
- .version = XTABLES_VERSION,
- .family = NFPROTO_IPV6,
- .size = XT_ALIGN(sizeof(struct ip6t_frag)),
- .userspacesize = XT_ALIGN(sizeof(struct ip6t_frag)),
- .help = frag_help,
- .init = frag_init,
- .print = frag_print,
- .save = frag_save,
- .x6_parse = frag_parse,
- .x6_options = frag_opts,
- };
- void
- _init(void)
- {
- xtables_register_match(&frag_mt6_reg);
- }
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