root/net/bridge/netfilter/ebt_ip6.c

DEFINITIONS

1. ebt_ip6_mt
2. ebt_ip6_mt_check
3. ebt_ip6_init
4. ebt_ip6_fini

/*
 *  ebt_ip6
 *
 *      Authors:
 *      Manohar Castelino <manohar.r.castelino@intel.com>
 *      Kuo-Lang Tseng <kuo-lang.tseng@intel.com>
 *      Jan Engelhardt <jengelh@computergmbh.de>
 *
 * Summary:
 * This is just a modification of the IPv4 code written by
 * Bart De Schuymer <bdschuym@pandora.be>
 * with the changes required to support IPv6
 *
 *  Jan, 2008
 */
#include <linux/ipv6.h>
#include <net/ipv6.h>
#include <linux/in.h>
#include <linux/module.h>
#include <net/dsfield.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_ip6.h>

struct tcpudphdr {
        __be16 src;
        __be16 dst;
};

static bool
ebt_ip6_mt(const struct sk_buff *skb, const struct xt_match_param *par)
{
        const struct ebt_ip6_info *info = par->matchinfo;
        const struct ipv6hdr *ih6;
        struct ipv6hdr _ip6h;
        const struct tcpudphdr *pptr;
        struct tcpudphdr _ports;
        struct in6_addr tmp_addr;
        int i;

        ih6 = skb_header_pointer(skb, 0, sizeof(_ip6h), &_ip6h);
        if (ih6 == NULL)
                return false;
        if (info->bitmask & EBT_IP6_TCLASS &&
           FWINV(info->tclass != ipv6_get_dsfield(ih6), EBT_IP6_TCLASS))
                return false;
        for (i = 0; i < 4; i++)
                tmp_addr.in6_u.u6_addr32[i] = ih6->saddr.in6_u.u6_addr32[i] &
                        info->smsk.in6_u.u6_addr32[i];
        if (info->bitmask & EBT_IP6_SOURCE &&
                FWINV((ipv6_addr_cmp(&tmp_addr, &info->saddr) != 0),
                        EBT_IP6_SOURCE))
                return false;
        for (i = 0; i < 4; i++)
                tmp_addr.in6_u.u6_addr32[i] = ih6->daddr.in6_u.u6_addr32[i] &
                        info->dmsk.in6_u.u6_addr32[i];
        if (info->bitmask & EBT_IP6_DEST &&
           FWINV((ipv6_addr_cmp(&tmp_addr, &info->daddr) != 0), EBT_IP6_DEST))
                return false;
        if (info->bitmask & EBT_IP6_PROTO) {
                uint8_t nexthdr = ih6->nexthdr;
                int offset_ph;

                offset_ph = ipv6_skip_exthdr(skb, sizeof(_ip6h), &nexthdr);
                if (offset_ph == -1)
                        return false;
                if (FWINV(info->protocol != nexthdr, EBT_IP6_PROTO))
                        return false;
                if (!(info->bitmask & EBT_IP6_DPORT) &&
                    !(info->bitmask & EBT_IP6_SPORT))
                        return true;
                pptr = skb_header_pointer(skb, offset_ph, sizeof(_ports),
                                          &_ports);
                if (pptr == NULL)
                        return false;
                if (info->bitmask & EBT_IP6_DPORT) {
                        u32 dst = ntohs(pptr->dst);
                        if (FWINV(dst < info->dport[0] ||
                                  dst > info->dport[1], EBT_IP6_DPORT))
                                return false;
                }
                if (info->bitmask & EBT_IP6_SPORT) {
                        u32 src = ntohs(pptr->src);
                        if (FWINV(src < info->sport[0] ||
                                  src > info->sport[1], EBT_IP6_SPORT))
                        return false;
                }
                return true;
        }
        return true;
}

static bool ebt_ip6_mt_check(const struct xt_mtchk_param *par)
{
        const struct ebt_entry *e = par->entryinfo;
        struct ebt_ip6_info *info = par->matchinfo;

        if (e->ethproto != htons(ETH_P_IPV6) || e->invflags & EBT_IPROTO)
                return false;
        if (info->bitmask & ~EBT_IP6_MASK || info->invflags & ~EBT_IP6_MASK)
                return false;
        if (info->bitmask & (EBT_IP6_DPORT | EBT_IP6_SPORT)) {
                if (info->invflags & EBT_IP6_PROTO)
                        return false;
                if (info->protocol != IPPROTO_TCP &&
                    info->protocol != IPPROTO_UDP &&
                    info->protocol != IPPROTO_UDPLITE &&
                    info->protocol != IPPROTO_SCTP &&
                    info->protocol != IPPROTO_DCCP)
                        return false;
        }
        if (info->bitmask & EBT_IP6_DPORT && info->dport[0] > info->dport[1])
                return false;
        if (info->bitmask & EBT_IP6_SPORT && info->sport[0] > info->sport[1])
                return false;
        return true;
}

static struct xt_match ebt_ip6_mt_reg __read_mostly = {
        .name           = "ip6",
        .revision       = 0,
        .family         = NFPROTO_BRIDGE,
        .match          = ebt_ip6_mt,
        .checkentry     = ebt_ip6_mt_check,
        .matchsize      = XT_ALIGN(sizeof(struct ebt_ip6_info)),
        .me             = THIS_MODULE,
};

static int __init ebt_ip6_init(void)
{
        return xt_register_match(&ebt_ip6_mt_reg);
}

static void __exit ebt_ip6_fini(void)
{
        xt_unregister_match(&ebt_ip6_mt_reg);
}

module_init(ebt_ip6_init);
module_exit(ebt_ip6_fini);
MODULE_DESCRIPTION("Ebtables: IPv6 protocol packet match");
MODULE_LICENSE("GPL");