net/bridge/netfilter/ebt_ip6.c

   1 /*
   2  *  ebt_ip6
   3  *
   4  *      Authors:
   5  *      Manohar Castelino <[email protected]>
   6  *      Kuo-Lang Tseng <[email protected]>
   7  *      Jan Engelhardt <[email protected]>
   8  *
   9  * Summary:
  10  * This is just a modification of the IPv4 code written by
  11  * Bart De Schuymer <[email protected]>
  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             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
 105 static 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
 139 static 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
 149 static int __init ebt_ip6_init(void)
 150 {
 151         return xt_register_match(&ebt_ip6_mt_reg);
 152 }
 153
 154 static void __exit ebt_ip6_fini(void)
 155 {
 156         xt_unregister_match(&ebt_ip6_mt_reg);
 157 }
 158
 159 module_init(ebt_ip6_init);
 160 module_exit(ebt_ip6_fini);
 161 MODULE_DESCRIPTION("Ebtables: IPv6 protocol packet match");
 162 MODULE_AUTHOR("Kuo-Lang Tseng <[email protected]>");
 163 MODULE_LICENSE("GPL");