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 struct tcpudphdr {
  26         __be16 src;
  27         __be16 dst;
  28 };
  29
  30 static bool
  31 ebt_ip6_mt(const struct sk_buff *skb, struct xt_action_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
  39         ih6 = skb_header_pointer(skb, 0, sizeof(_ip6h), &_ip6h);
  40         if (ih6 == NULL)
  41                 return false;
  42         if (info->bitmask & EBT_IP6_TCLASS &&
  43            FWINV(info->tclass != ipv6_get_dsfield(ih6), EBT_IP6_TCLASS))
  44                 return false;
  45         if (FWINV(ipv6_masked_addr_cmp(&ih6->saddr, &info->smsk,
  46                                        &info->saddr), EBT_IP6_SOURCE) ||
  47             FWINV(ipv6_masked_addr_cmp(&ih6->daddr, &info->dmsk,
  48                                        &info->daddr), EBT_IP6_DEST))
  49                 return false;
  50         if (info->bitmask & EBT_IP6_PROTO) {
  51                 uint8_t nexthdr = ih6->nexthdr;
  52                 int offset_ph;
  53
  54                 offset_ph = ipv6_skip_exthdr(skb, sizeof(_ip6h), &nexthdr);
  55                 if (offset_ph == -1)
  56                         return false;
  57                 if (FWINV(info->protocol != nexthdr, EBT_IP6_PROTO))
  58                         return false;
  59                 if (!(info->bitmask & EBT_IP6_DPORT) &&
  60                     !(info->bitmask & EBT_IP6_SPORT))
  61                         return true;
  62                 pptr = skb_header_pointer(skb, offset_ph, sizeof(_ports),
  63                                           &_ports);
  64                 if (pptr == NULL)
  65                         return false;
  66                 if (info->bitmask & EBT_IP6_DPORT) {
  67                         u32 dst = ntohs(pptr->dst);
  68                         if (FWINV(dst < info->dport[0] ||
  69                                   dst > info->dport[1], EBT_IP6_DPORT))
  70                                 return false;
  71                 }
  72                 if (info->bitmask & EBT_IP6_SPORT) {
  73                         u32 src = ntohs(pptr->src);
  74                         if (FWINV(src < info->sport[0] ||
  75                                   src > info->sport[1], EBT_IP6_SPORT))
  76                         return false;
  77                 }
  78                 return true;
  79         }
  80         return true;
  81 }
  82
  83 static int ebt_ip6_mt_check(const struct xt_mtchk_param *par)
  84 {
  85         const struct ebt_entry *e = par->entryinfo;
  86         struct ebt_ip6_info *info = par->matchinfo;
  87
  88         if (e->ethproto != htons(ETH_P_IPV6) || e->invflags & EBT_IPROTO)
  89                 return -EINVAL;
  90         if (info->bitmask & ~EBT_IP6_MASK || info->invflags & ~EBT_IP6_MASK)
  91                 return -EINVAL;
  92         if (info->bitmask & (EBT_IP6_DPORT | EBT_IP6_SPORT)) {
  93                 if (info->invflags & EBT_IP6_PROTO)
  94                         return -EINVAL;
  95                 if (info->protocol != IPPROTO_TCP &&
  96                     info->protocol != IPPROTO_UDP &&
  97                     info->protocol != IPPROTO_UDPLITE &&
  98                     info->protocol != IPPROTO_SCTP &&
  99                     info->protocol != IPPROTO_DCCP)
 100                         return -EINVAL;
 101         }
 102         if (info->bitmask & EBT_IP6_DPORT && info->dport[0] > info->dport[1])
 103                 return -EINVAL;
 104         if (info->bitmask & EBT_IP6_SPORT && info->sport[0] > info->sport[1])
 105                 return -EINVAL;
 106         return 0;
 107 }
 108
 109 static struct xt_match ebt_ip6_mt_reg __read_mostly = {
 110         .name           = "ip6",
 111         .revision       = 0,
 112         .family         = NFPROTO_BRIDGE,
 113         .match          = ebt_ip6_mt,
 114         .checkentry     = ebt_ip6_mt_check,
 115         .matchsize      = sizeof(struct ebt_ip6_info),
 116         .me             = THIS_MODULE,
 117 };
 118
 119 static int __init ebt_ip6_init(void)
 120 {
 121         return xt_register_match(&ebt_ip6_mt_reg);
 122 }
 123
 124 static void __exit ebt_ip6_fini(void)
 125 {
 126         xt_unregister_match(&ebt_ip6_mt_reg);
 127 }
 128
 129 module_init(ebt_ip6_init);
 130 module_exit(ebt_ip6_fini);
 131 MODULE_DESCRIPTION("Ebtables: IPv6 protocol packet match");
 132 MODULE_AUTHOR("Kuo-Lang Tseng <kuo-lang.tseng@intel.com>");
 133 MODULE_LICENSE("GPL");