LXR linux/net/bridge/netfilter/ebt

   1/*
   2 *  ebt_ip6
   3 *
   4 *      Authors:
   5 *      Manohar Castelino <manohar.r.castelino@intel.com>
   6 *      Kuo-Lang Tseng <kuo-lang.tseng@intel.com>
   7 *      Jan Engelhardt <jengelh@computergmbh.de>
   8 *
   9 * Summary:
  10 * This is just a modification of the IPv4 code written by
  11 * Bart De Schuymer <bdschuym@pandora.be>
  12 * with the changes required to support IPv6
  13 *
  14 *  Jan, 2008
  15 */
  16#include <linux/ipv6.h>
  17#include <net/ipv6.h>
  18#include <linux/in.h>
  19#include <linux/module.h>
  20#include <net/dsfield.h>
  21#include <linux/netfilter/x_tables.h>
  22#include <linux/netfilter_bridge/ebtables.h>
  23#include <linux/netfilter_bridge/ebt_ip6.h>
  24
  25struct tcpudphdr {
  26        __be16 src;
  27        __be16 dst;
  28};
  29
  30static bool
  31ebt_ip6_mt(const struct sk_buff *skb, const struct xt_match_param *par)
  32{
  33        const struct ebt_ip6_info *info = par->matchinfo;
  34        const struct ipv6hdr *ih6;
  35        struct ipv6hdr _ip6h;
  36        const struct tcpudphdr *pptr;
  37        struct tcpudphdr _ports;
  38        struct in6_addr tmp_addr;
  39        int i;
  40
  41        ih6 = skb_header_pointer(skb, 0, sizeof(_ip6h), &_ip6h);
  42        if (ih6 == NULL)
  43                return false;
  44        if (info->bitmask & EBT_IP6_TCLASS &&
  45           FWINV(info->tclass != ipv6_get_dsfield(ih6), EBT_IP6_TCLASS))
  46                return false;
  47        for (i = 0; i < 4; i++)
  48                tmp_addr.in6_u.u6_addr32[i] = ih6->saddr.in6_u.u6_addr32[i] &
  49                        info->smsk.in6_u.u6_addr32[i];
  50        if (info->bitmask & EBT_IP6_SOURCE &&
  51                FWINV((ipv6_addr_cmp(&tmp_addr, &info->saddr) != 0),
  52                        EBT_IP6_SOURCE))
  53                return false;
  54        for (i = 0; i < 4; i++)
  55                tmp_addr.in6_u.u6_addr32[i] = ih6->daddr.in6_u.u6_addr32[i] &
  56                        info->dmsk.in6_u.u6_addr32[i];
  57        if (info->bitmask & EBT_IP6_DEST &&
  58           FWINV((ipv6_addr_cmp(&tmp_addr, &info->daddr) != 0), EBT_IP6_DEST))
  59                return false;
  60        if (info->bitmask & EBT_IP6_PROTO) {
  61                uint8_t nexthdr = ih6->nexthdr;
  62                int offset_ph;
  63
  64                offset_ph = ipv6_skip_exthdr(skb, sizeof(_ip6h), &nexthdr);
  65                if (offset_ph == -1)
  66                        return false;
  67                if (FWINV(info->protocol != nexthdr, EBT_IP6_PROTO))
  68                        return false;
  69                if (!(info->bitmask & EBT_IP6_DPORT) &&
  70                    !(info->bitmask & EBT_IP6_SPORT))
  71                        return true;
  72                pptr = skb_header_pointer(skb, offset_ph, sizeof(_ports),
  73                                          &_ports);
  74                if (pptr == NULL)
  75                        return false;
  76                if (info->bitmask & EBT_IP6_DPORT) {
  77                        u32 dst = ntohs(pptr->dst);
  78                        if (FWINV(dst < info->dport[0] ||
  79                                  dst > info->dport[1], EBT_IP6_DPORT))
  80                                return false;
  81                }
  82                if (info->bitmask & EBT_IP6_SPORT) {
  83                        u32 src = ntohs(pptr->src);
  84                        if (FWINV(src < info->sport[0] ||
  85                                  src > info->sport[1], EBT_IP6_SPORT))
  86                        return false;
  87                }
  88                return true;
  89        }
  90        return true;
  91}
  92
  93static bool ebt_ip6_mt_check(const struct xt_mtchk_param *par)
  94{
  95        const struct ebt_entry *e = par->entryinfo;
  96        struct ebt_ip6_info *info = par->matchinfo;
  97
  98        if (e->ethproto != htons(ETH_P_IPV6) || e->invflags & EBT_IPROTO)
  99                return false;
 100        if (info->bitmask & ~EBT_IP6_MASK || info->invflags & ~EBT_IP6_MASK)
 101                return false;
 102        if (info->bitmask & (EBT_IP6_DPORT | EBT_IP6_SPORT)) {
 103                if (info->invflags & EBT_IP6_PROTO)
 104                        return false;
 105                if (info->protocol != IPPROTO_TCP &&
 106                    info->protocol != IPPROTO_UDP &&
 107                    info->protocol != IPPROTO_UDPLITE &&
 108                    info->protocol != IPPROTO_SCTP &&
 109                    info->protocol != IPPROTO_DCCP)
 110                        return false;
 111        }
 112        if (info->bitmask & EBT_IP6_DPORT && info->dport[0] > info->dport[1])
 113                return false;
 114        if (info->bitmask & EBT_IP6_SPORT && info->sport[0] > info->sport[1])
 115                return false;
 116        return true;
 117}
 118
 119static struct xt_match ebt_ip6_mt_reg __read_mostly = {
 120        .name           = "ip6",
 121        .revision       = 0,
 122        .family         = NFPROTO_BRIDGE,
 123        .match          = ebt_ip6_mt,
 124        .checkentry     = ebt_ip6_mt_check,
 125        .matchsize      = XT_ALIGN(sizeof(struct ebt_ip6_info)),
 126        .me             = THIS_MODULE,
 127};
 128
 129static int __init ebt_ip6_init(void)
 130{
 131        return xt_register_match(&ebt_ip6_mt_reg);
 132}
 133
 134static void __exit ebt_ip6_fini(void)
 135{
 136        xt_unregister_match(&ebt_ip6_mt_reg);
 137}
 138
 139module_init(ebt_ip6_init);
 140module_exit(ebt_ip6_fini);
 141MODULE_DESCRIPTION("Ebtables: IPv6 protocol packet match");
 142MODULE_LICENSE("GPL");
 143