diff options
Diffstat (limited to 'net/ipv6/netfilter/ip6t_rt.c')
| -rw-r--r-- | net/ipv6/netfilter/ip6t_rt.c | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/net/ipv6/netfilter/ip6t_rt.c b/net/ipv6/netfilter/ip6t_rt.c new file mode 100644 index 00000000..d8488c50 --- /dev/null +++ b/net/ipv6/netfilter/ip6t_rt.c @@ -0,0 +1,225 @@ +/* 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; + 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); + 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); |