net/bridge/netfilter/ebt_ip6.c

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