| /* 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); |
| |
| if (ap == NULL) { |
| par->hotdrop = true; |
| return false; |
| } |
| |
| 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); |
| if (ap == NULL) { |
| par->hotdrop = true; |
| return false; |
| } |
| |
| 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); |