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@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
  17 #include <linux/netfilter_bridge/ebtables.h>
  18 #include <linux/netfilter_bridge/ebt_ip6.h>
  19 #include <linux/ipv6.h>
  20 #include <net/ipv6.h>
  21 #include <linux/in.h>
  22 #include <linux/module.h>
  23 #include <net/dsfield.h>
  24
  25 struct tcpudphdr {
  26         __be16 src;
  27         __be16 dst;
  28 };
  29
  30 static int ebt_filter_ip6(const struct sk_buff *skb,
  31    const struct net_device *in,
  32    const struct net_device *out, const void *data,
  33    unsigned int datalen)
  34 {
  35         const struct ebt_ip6_info *info = (struct ebt_ip6_info *)data;
  36         const struct ipv6hdr *ih6;
  37         struct ipv6hdr _ip6h;
  38         const struct tcpudphdr *pptr;
  39         struct tcpudphdr _ports;
  40         struct in6_addr tmp_addr;
  41         int i;
  42
  43         ih6 = skb_header_pointer(skb, 0, sizeof(_ip6h), &_ip6h);
  44         if (ih6 == NULL)
  45                 return EBT_NOMATCH;
  46         if (info->bitmask & EBT_IP6_TCLASS &&
  47            FWINV(info->tclass != ipv6_get_dsfield(ih6), EBT_IP6_TCLASS))
  48                 return EBT_NOMATCH;
  49         for (i = 0; i < 4; i++)
  50                 tmp_addr.in6_u.u6_addr32[i] = ih6->saddr.in6_u.u6_addr32[i] &
  51                         info->smsk.in6_u.u6_addr32[i];
  52         if (info->bitmask & EBT_IP6_SOURCE &&
  53                 FWINV((ipv6_addr_cmp(&tmp_addr, &info->saddr) != 0),
  54                         EBT_IP6_SOURCE))
  55                 return EBT_NOMATCH;
  56         for (i = 0; i < 4; i++)
  57                 tmp_addr.in6_u.u6_addr32[i] = ih6->daddr.in6_u.u6_addr32[i] &
  58                         info->dmsk.in6_u.u6_addr32[i];
  59         if (info->bitmask & EBT_IP6_DEST &&
  60            FWINV((ipv6_addr_cmp(&tmp_addr, &info->daddr) != 0), EBT_IP6_DEST))
  61                 return EBT_NOMATCH;
  62         if (info->bitmask & EBT_IP6_PROTO) {
  63                 uint8_t nexthdr = ih6->nexthdr;
  64                 int offset_ph;
  65
  66                 offset_ph = ipv6_skip_exthdr(skb, sizeof(_ip6h), &nexthdr);
  67                 if (offset_ph == -1)
  68                         return EBT_NOMATCH;
  69                 if (FWINV(info->protocol != nexthdr, EBT_IP6_PROTO))
  70                         return EBT_NOMATCH;
  71                 if (!(info->bitmask & EBT_IP6_DPORT) &&
  72                     !(info->bitmask & EBT_IP6_SPORT))
  73                         return EBT_MATCH;
  74                 pptr = skb_header_pointer(skb, offset_ph, sizeof(_ports),
  75                                           &_ports);
  76                 if (pptr == NULL)
  77                         return EBT_NOMATCH;
  78                 if (info->bitmask & EBT_IP6_DPORT) {
  79                         u32 dst = ntohs(pptr->dst);
  80                         if (FWINV(dst < info->dport[0] ||
  81                                   dst > info->dport[1], EBT_IP6_DPORT))
  82                                 return EBT_NOMATCH;
  83                 }
  84                 if (info->bitmask & EBT_IP6_SPORT) {
  85                         u32 src = ntohs(pptr->src);
  86                         if (FWINV(src < info->sport[0] ||
  87                                   src > info->sport[1], EBT_IP6_SPORT))
  88                         return EBT_NOMATCH;
  89                 }
  90                 return EBT_MATCH;
  91         }
  92         return EBT_MATCH;
  93 }
  94
  95 static int ebt_ip6_check(const char *tablename, unsigned int hookmask,
  96    const struct ebt_entry *e, void *data, unsigned int datalen)
  97 {
  98         struct ebt_ip6_info *info = (struct ebt_ip6_info *)data;
  99
 100         if (datalen != EBT_ALIGN(sizeof(struct ebt_ip6_info)))
 101                 return -EINVAL;
 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         return 0;
 121 }
 122
 123 static struct ebt_match filter_ip6 =
 124 {
 125         .name           = EBT_IP6_MATCH,
 126         .match          = ebt_filter_ip6,
 127         .check          = ebt_ip6_check,
 128         .me             = THIS_MODULE,
 129 };
 130
 131 static int __init ebt_ip6_init(void)
 132 {
 133         return ebt_register_match(&filter_ip6);
 134 }
 135
 136 static void __exit ebt_ip6_fini(void)
 137 {
 138         ebt_unregister_match(&filter_ip6);
 139 }
 140
 141 module_init(ebt_ip6_init);
 142 module_exit(ebt_ip6_fini);
 143 MODULE_DESCRIPTION("Ebtables: IPv6 protocol packet match");
 144 MODULE_LICENSE("GPL");