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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@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
  25 struct tcpudphdr {
  26         __be16 src;
  27         __be16 dst;
  28 };
  29
  30 static bool
  31 ebt_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
  93 static 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
 119 static 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
 129 static int __init ebt_ip6_init(void)
 130 {
 131         return xt_register_match(&ebt_ip6_mt_reg);
 132 }
 133
 134 static void __exit ebt_ip6_fini(void)
 135 {
 136         xt_unregister_match(&ebt_ip6_mt_reg);
 137 }
 138
 139 module_init(ebt_ip6_init);
 140 module_exit(ebt_ip6_fini);
 141 MODULE_DESCRIPTION("Ebtables: IPv6 protocol packet match");
 142 MODULE_LICENSE("GPL");