linux/net/bridge/netfilter/ebt_ip6.c
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   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@medozas.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
  25union pkthdr {
  26        struct {
  27                __be16 src;
  28                __be16 dst;
  29        } tcpudphdr;
  30        struct {
  31                u8 type;
  32                u8 code;
  33        } icmphdr;
  34};
  35
  36static bool
  37ebt_ip6_mt(const struct sk_buff *skb, struct xt_action_param *par)
  38{
  39        const struct ebt_ip6_info *info = par->matchinfo;
  40        const struct ipv6hdr *ih6;
  41        struct ipv6hdr _ip6h;
  42        const union pkthdr *pptr;
  43        union pkthdr _pkthdr;
  44
  45        ih6 = skb_header_pointer(skb, 0, sizeof(_ip6h), &_ip6h);
  46        if (ih6 == NULL)
  47                return false;
  48        if ((info->bitmask & EBT_IP6_TCLASS) &&
  49            NF_INVF(info, EBT_IP6_TCLASS,
  50                    info->tclass != ipv6_get_dsfield(ih6)))
  51                return false;
  52        if (((info->bitmask & EBT_IP6_SOURCE) &&
  53             NF_INVF(info, EBT_IP6_SOURCE,
  54                     ipv6_masked_addr_cmp(&ih6->saddr, &info->smsk,
  55                                          &info->saddr))) ||
  56            ((info->bitmask & EBT_IP6_DEST) &&
  57             NF_INVF(info, EBT_IP6_DEST,
  58                     ipv6_masked_addr_cmp(&ih6->daddr, &info->dmsk,
  59                                          &info->daddr))))
  60                return false;
  61        if (info->bitmask & EBT_IP6_PROTO) {
  62                uint8_t nexthdr = ih6->nexthdr;
  63                __be16 frag_off;
  64                int offset_ph;
  65
  66                offset_ph = ipv6_skip_exthdr(skb, sizeof(_ip6h), &nexthdr, &frag_off);
  67                if (offset_ph == -1)
  68                        return false;
  69                if (NF_INVF(info, EBT_IP6_PROTO, info->protocol != nexthdr))
  70                        return false;
  71                if (!(info->bitmask & (EBT_IP6_DPORT |
  72                                       EBT_IP6_SPORT | EBT_IP6_ICMP6)))
  73                        return true;
  74
  75                /* min icmpv6 headersize is 4, so sizeof(_pkthdr) is ok. */
  76                pptr = skb_header_pointer(skb, offset_ph, sizeof(_pkthdr),
  77                                          &_pkthdr);
  78                if (pptr == NULL)
  79                        return false;
  80                if (info->bitmask & EBT_IP6_DPORT) {
  81                        u16 dst = ntohs(pptr->tcpudphdr.dst);
  82                        if (NF_INVF(info, EBT_IP6_DPORT,
  83                                    dst < info->dport[0] ||
  84                                    dst > info->dport[1]))
  85                                return false;
  86                }
  87                if (info->bitmask & EBT_IP6_SPORT) {
  88                        u16 src = ntohs(pptr->tcpudphdr.src);
  89                        if (NF_INVF(info, EBT_IP6_SPORT,
  90                                    src < info->sport[0] ||
  91                                    src > info->sport[1]))
  92                                return false;
  93                }
  94                if ((info->bitmask & EBT_IP6_ICMP6) &&
  95                    NF_INVF(info, EBT_IP6_ICMP6,
  96                            pptr->icmphdr.type < info->icmpv6_type[0] ||
  97                            pptr->icmphdr.type > info->icmpv6_type[1] ||
  98                            pptr->icmphdr.code < info->icmpv6_code[0] ||
  99                            pptr->icmphdr.code > info->icmpv6_code[1]))
 100                        return false;
 101        }
 102        return true;
 103}
 104
 105static int ebt_ip6_mt_check(const struct xt_mtchk_param *par)
 106{
 107        const struct ebt_entry *e = par->entryinfo;
 108        struct ebt_ip6_info *info = par->matchinfo;
 109
 110        if (e->ethproto != htons(ETH_P_IPV6) || e->invflags & EBT_IPROTO)
 111                return -EINVAL;
 112        if (info->bitmask & ~EBT_IP6_MASK || info->invflags & ~EBT_IP6_MASK)
 113                return -EINVAL;
 114        if (info->bitmask & (EBT_IP6_DPORT | EBT_IP6_SPORT)) {
 115                if (info->invflags & EBT_IP6_PROTO)
 116                        return -EINVAL;
 117                if (info->protocol != IPPROTO_TCP &&
 118                    info->protocol != IPPROTO_UDP &&
 119                    info->protocol != IPPROTO_UDPLITE &&
 120                    info->protocol != IPPROTO_SCTP &&
 121                    info->protocol != IPPROTO_DCCP)
 122                        return -EINVAL;
 123        }
 124        if (info->bitmask & EBT_IP6_DPORT && info->dport[0] > info->dport[1])
 125                return -EINVAL;
 126        if (info->bitmask & EBT_IP6_SPORT && info->sport[0] > info->sport[1])
 127                return -EINVAL;
 128        if (info->bitmask & EBT_IP6_ICMP6) {
 129                if ((info->invflags & EBT_IP6_PROTO) ||
 130                     info->protocol != IPPROTO_ICMPV6)
 131                        return -EINVAL;
 132                if (info->icmpv6_type[0] > info->icmpv6_type[1] ||
 133                    info->icmpv6_code[0] > info->icmpv6_code[1])
 134                        return -EINVAL;
 135        }
 136        return 0;
 137}
 138
 139static struct xt_match ebt_ip6_mt_reg __read_mostly = {
 140        .name           = "ip6",
 141        .revision       = 0,
 142        .family         = NFPROTO_BRIDGE,
 143        .match          = ebt_ip6_mt,
 144        .checkentry     = ebt_ip6_mt_check,
 145        .matchsize      = sizeof(struct ebt_ip6_info),
 146        .me             = THIS_MODULE,
 147};
 148
 149static int __init ebt_ip6_init(void)
 150{
 151        return xt_register_match(&ebt_ip6_mt_reg);
 152}
 153
 154static void __exit ebt_ip6_fini(void)
 155{
 156        xt_unregister_match(&ebt_ip6_mt_reg);
 157}
 158
 159module_init(ebt_ip6_init);
 160module_exit(ebt_ip6_fini);
 161MODULE_DESCRIPTION("Ebtables: IPv6 protocol packet match");
 162MODULE_AUTHOR("Kuo-Lang Tseng <kuo-lang.tseng@intel.com>");
 163MODULE_LICENSE("GPL");
 164