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- /* Kernel module to match ROUTING parameters. */
- /* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
- #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
- #include <linux/module.h>
- #include <linux/skbuff.h>
- #include <linux/ipv6.h>
- #include <linux/types.h>
- #include <net/checksum.h>
- #include <net/ipv6.h>
- #include <asm/byteorder.h>
- #include <linux/netfilter/x_tables.h>
- #include <linux/netfilter_ipv6/ip6_tables.h>
- #include <linux/netfilter_ipv6/ip6t_rt.h>
- MODULE_LICENSE("GPL");
- MODULE_DESCRIPTION("Xtables: IPv6 Routing Header match");
- MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
- /* Returns 1 if the id is matched by the range, 0 otherwise */
- static inline bool
- segsleft_match(u_int32_t min, u_int32_t max, u_int32_t id, bool invert)
- {
- bool r;
- pr_debug("segsleft_match:%c 0x%x <= 0x%x <= 0x%x\n",
- invert ? '!' : ' ', min, id, max);
- r = (id >= min && id <= max) ^ invert;
- pr_debug(" result %s\n", r ? "PASS" : "FAILED");
- return r;
- }
- static bool rt_mt6(const struct sk_buff *skb, struct xt_action_param *par)
- {
- struct ipv6_rt_hdr _route;
- const struct ipv6_rt_hdr *rh;
- const struct ip6t_rt *rtinfo = par->matchinfo;
- unsigned int temp;
- unsigned int ptr = 0;
- unsigned int hdrlen = 0;
- bool ret = false;
- struct in6_addr _addr;
- const struct in6_addr *ap;
- int err;
- err = ipv6_find_hdr(skb, &ptr, NEXTHDR_ROUTING, NULL, NULL);
- if (err < 0) {
- if (err != -ENOENT)
- par->hotdrop = true;
- return false;
- }
- rh = skb_header_pointer(skb, ptr, sizeof(_route), &_route);
- if (rh == NULL) {
- par->hotdrop = true;
- return false;
- }
- hdrlen = ipv6_optlen(rh);
- if (skb->len - ptr < hdrlen) {
- /* Pcket smaller than its length field */
- return false;
- }
- pr_debug("IPv6 RT LEN %u %u ", hdrlen, rh->hdrlen);
- pr_debug("TYPE %04X ", rh->type);
- pr_debug("SGS_LEFT %u %02X\n", rh->segments_left, rh->segments_left);
- pr_debug("IPv6 RT segsleft %02X ",
- segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1],
- rh->segments_left,
- !!(rtinfo->invflags & IP6T_RT_INV_SGS)));
- pr_debug("type %02X %02X %02X ",
- rtinfo->rt_type, rh->type,
- (!(rtinfo->flags & IP6T_RT_TYP) ||
- ((rtinfo->rt_type == rh->type) ^
- !!(rtinfo->invflags & IP6T_RT_INV_TYP))));
- pr_debug("len %02X %04X %02X ",
- rtinfo->hdrlen, hdrlen,
- !(rtinfo->flags & IP6T_RT_LEN) ||
- ((rtinfo->hdrlen == hdrlen) ^
- !!(rtinfo->invflags & IP6T_RT_INV_LEN)));
- pr_debug("res %02X %02X %02X ",
- rtinfo->flags & IP6T_RT_RES,
- ((const struct rt0_hdr *)rh)->reserved,
- !((rtinfo->flags & IP6T_RT_RES) &&
- (((const struct rt0_hdr *)rh)->reserved)));
- ret = (rh != NULL) &&
- (segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1],
- rh->segments_left,
- !!(rtinfo->invflags & IP6T_RT_INV_SGS))) &&
- (!(rtinfo->flags & IP6T_RT_LEN) ||
- ((rtinfo->hdrlen == hdrlen) ^
- !!(rtinfo->invflags & IP6T_RT_INV_LEN))) &&
- (!(rtinfo->flags & IP6T_RT_TYP) ||
- ((rtinfo->rt_type == rh->type) ^
- !!(rtinfo->invflags & IP6T_RT_INV_TYP)));
- if (ret && (rtinfo->flags & IP6T_RT_RES)) {
- const u_int32_t *rp;
- u_int32_t _reserved;
- rp = skb_header_pointer(skb,
- ptr + offsetof(struct rt0_hdr,
- reserved),
- sizeof(_reserved),
- &_reserved);
- ret = (*rp == 0);
- }
- pr_debug("#%d ", rtinfo->addrnr);
- if (!(rtinfo->flags & IP6T_RT_FST)) {
- return ret;
- } else if (rtinfo->flags & IP6T_RT_FST_NSTRICT) {
- pr_debug("Not strict ");
- if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) {
- pr_debug("There isn't enough space\n");
- return false;
- } else {
- unsigned int i = 0;
- pr_debug("#%d ", rtinfo->addrnr);
- for (temp = 0;
- temp < (unsigned int)((hdrlen - 8) / 16);
- temp++) {
- ap = skb_header_pointer(skb,
- ptr
- + sizeof(struct rt0_hdr)
- + temp * sizeof(_addr),
- sizeof(_addr),
- &_addr);
- BUG_ON(ap == NULL);
- if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) {
- pr_debug("i=%d temp=%d;\n", i, temp);
- i++;
- }
- if (i == rtinfo->addrnr)
- break;
- }
- pr_debug("i=%d #%d\n", i, rtinfo->addrnr);
- if (i == rtinfo->addrnr)
- return ret;
- else
- return false;
- }
- } else {
- pr_debug("Strict ");
- if (rtinfo->addrnr > (unsigned int)((hdrlen - 8) / 16)) {
- pr_debug("There isn't enough space\n");
- return false;
- } else {
- pr_debug("#%d ", rtinfo->addrnr);
- for (temp = 0; temp < rtinfo->addrnr; temp++) {
- ap = skb_header_pointer(skb,
- ptr
- + sizeof(struct rt0_hdr)
- + temp * sizeof(_addr),
- sizeof(_addr),
- &_addr);
- BUG_ON(ap == NULL);
- if (!ipv6_addr_equal(ap, &rtinfo->addrs[temp]))
- break;
- }
- pr_debug("temp=%d #%d\n", temp, rtinfo->addrnr);
- if (temp == rtinfo->addrnr &&
- temp == (unsigned int)((hdrlen - 8) / 16))
- return ret;
- else
- return false;
- }
- }
- return false;
- }
- static int rt_mt6_check(const struct xt_mtchk_param *par)
- {
- const struct ip6t_rt *rtinfo = par->matchinfo;
- if (rtinfo->invflags & ~IP6T_RT_INV_MASK) {
- pr_debug("unknown flags %X\n", rtinfo->invflags);
- return -EINVAL;
- }
- if ((rtinfo->flags & (IP6T_RT_RES | IP6T_RT_FST_MASK)) &&
- (!(rtinfo->flags & IP6T_RT_TYP) ||
- (rtinfo->rt_type != 0) ||
- (rtinfo->invflags & IP6T_RT_INV_TYP))) {
- pr_debug("`--rt-type 0' required before `--rt-0-*'");
- return -EINVAL;
- }
- return 0;
- }
- static struct xt_match rt_mt6_reg __read_mostly = {
- .name = "rt",
- .family = NFPROTO_IPV6,
- .match = rt_mt6,
- .matchsize = sizeof(struct ip6t_rt),
- .checkentry = rt_mt6_check,
- .me = THIS_MODULE,
- };
- static int __init rt_mt6_init(void)
- {
- return xt_register_match(&rt_mt6_reg);
- }
- static void __exit rt_mt6_exit(void)
- {
- xt_unregister_match(&rt_mt6_reg);
- }
- module_init(rt_mt6_init);
- module_exit(rt_mt6_exit);
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