linux/net/ipv6/netfilter.c
<<
>>
Prefs
   1#include <linux/kernel.h>
   2#include <linux/init.h>
   3#include <linux/ipv6.h>
   4#include <linux/netfilter.h>
   5#include <linux/netfilter_ipv6.h>
   6#include <linux/export.h>
   7#include <net/dst.h>
   8#include <net/ipv6.h>
   9#include <net/ip6_route.h>
  10#include <net/xfrm.h>
  11#include <net/ip6_checksum.h>
  12#include <net/netfilter/nf_queue.h>
  13
  14int ip6_route_me_harder(struct sk_buff *skb)
  15{
  16        struct net *net = dev_net(skb_dst(skb)->dev);
  17        const struct ipv6hdr *iph = ipv6_hdr(skb);
  18        unsigned int hh_len;
  19        struct dst_entry *dst;
  20        struct flowi6 fl6 = {
  21                .flowi6_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0,
  22                .flowi6_mark = skb->mark,
  23                .daddr = iph->daddr,
  24                .saddr = iph->saddr,
  25        };
  26
  27        dst = ip6_route_output(net, skb->sk, &fl6);
  28        if (dst->error) {
  29                IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
  30                LIMIT_NETDEBUG(KERN_DEBUG "ip6_route_me_harder: No more route.\n");
  31                dst_release(dst);
  32                return -EINVAL;
  33        }
  34
  35        /* Drop old route. */
  36        skb_dst_drop(skb);
  37
  38        skb_dst_set(skb, dst);
  39
  40#ifdef CONFIG_XFRM
  41        if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
  42            xfrm_decode_session(skb, flowi6_to_flowi(&fl6), AF_INET6) == 0) {
  43                skb_dst_set(skb, NULL);
  44                dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), skb->sk, 0);
  45                if (IS_ERR(dst))
  46                        return -1;
  47                skb_dst_set(skb, dst);
  48        }
  49#endif
  50
  51        /* Change in oif may mean change in hh_len. */
  52        hh_len = skb_dst(skb)->dev->hard_header_len;
  53        if (skb_headroom(skb) < hh_len &&
  54            pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
  55                             0, GFP_ATOMIC))
  56                return -1;
  57
  58        return 0;
  59}
  60EXPORT_SYMBOL(ip6_route_me_harder);
  61
  62/*
  63 * Extra routing may needed on local out, as the QUEUE target never
  64 * returns control to the table.
  65 */
  66
  67struct ip6_rt_info {
  68        struct in6_addr daddr;
  69        struct in6_addr saddr;
  70        u_int32_t mark;
  71};
  72
  73static void nf_ip6_saveroute(const struct sk_buff *skb,
  74                             struct nf_queue_entry *entry)
  75{
  76        struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
  77
  78        if (entry->hook == NF_INET_LOCAL_OUT) {
  79                const struct ipv6hdr *iph = ipv6_hdr(skb);
  80
  81                rt_info->daddr = iph->daddr;
  82                rt_info->saddr = iph->saddr;
  83                rt_info->mark = skb->mark;
  84        }
  85}
  86
  87static int nf_ip6_reroute(struct sk_buff *skb,
  88                          const struct nf_queue_entry *entry)
  89{
  90        struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
  91
  92        if (entry->hook == NF_INET_LOCAL_OUT) {
  93                const struct ipv6hdr *iph = ipv6_hdr(skb);
  94                if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) ||
  95                    !ipv6_addr_equal(&iph->saddr, &rt_info->saddr) ||
  96                    skb->mark != rt_info->mark)
  97                        return ip6_route_me_harder(skb);
  98        }
  99        return 0;
 100}
 101
 102static int nf_ip6_route(struct net *net, struct dst_entry **dst,
 103                        struct flowi *fl, bool strict)
 104{
 105        static const struct ipv6_pinfo fake_pinfo;
 106        static const struct inet_sock fake_sk = {
 107                /* makes ip6_route_output set RT6_LOOKUP_F_IFACE: */
 108                .sk.sk_bound_dev_if = 1,
 109                .pinet6 = (struct ipv6_pinfo *) &fake_pinfo,
 110        };
 111        const void *sk = strict ? &fake_sk : NULL;
 112        struct dst_entry *result;
 113        int err;
 114
 115        result = ip6_route_output(net, sk, &fl->u.ip6);
 116        err = result->error;
 117        if (err)
 118                dst_release(result);
 119        else
 120                *dst = result;
 121        return err;
 122}
 123
 124__sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook,
 125                             unsigned int dataoff, u_int8_t protocol)
 126{
 127        const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 128        __sum16 csum = 0;
 129
 130        switch (skb->ip_summed) {
 131        case CHECKSUM_COMPLETE:
 132                if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN)
 133                        break;
 134                if (!csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
 135                                     skb->len - dataoff, protocol,
 136                                     csum_sub(skb->csum,
 137                                              skb_checksum(skb, 0,
 138                                                           dataoff, 0)))) {
 139                        skb->ip_summed = CHECKSUM_UNNECESSARY;
 140                        break;
 141                }
 142                /* fall through */
 143        case CHECKSUM_NONE:
 144                skb->csum = ~csum_unfold(
 145                                csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
 146                                             skb->len - dataoff,
 147                                             protocol,
 148                                             csum_sub(0,
 149                                                      skb_checksum(skb, 0,
 150                                                                   dataoff, 0))));
 151                csum = __skb_checksum_complete(skb);
 152        }
 153        return csum;
 154}
 155EXPORT_SYMBOL(nf_ip6_checksum);
 156
 157static __sum16 nf_ip6_checksum_partial(struct sk_buff *skb, unsigned int hook,
 158                                       unsigned int dataoff, unsigned int len,
 159                                       u_int8_t protocol)
 160{
 161        const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 162        __wsum hsum;
 163        __sum16 csum = 0;
 164
 165        switch (skb->ip_summed) {
 166        case CHECKSUM_COMPLETE:
 167                if (len == skb->len - dataoff)
 168                        return nf_ip6_checksum(skb, hook, dataoff, protocol);
 169                /* fall through */
 170        case CHECKSUM_NONE:
 171                hsum = skb_checksum(skb, 0, dataoff, 0);
 172                skb->csum = ~csum_unfold(csum_ipv6_magic(&ip6h->saddr,
 173                                                         &ip6h->daddr,
 174                                                         skb->len - dataoff,
 175                                                         protocol,
 176                                                         csum_sub(0, hsum)));
 177                skb->ip_summed = CHECKSUM_NONE;
 178                return __skb_checksum_complete_head(skb, dataoff + len);
 179        }
 180        return csum;
 181};
 182
 183static const struct nf_afinfo nf_ip6_afinfo = {
 184        .family                 = AF_INET6,
 185        .checksum               = nf_ip6_checksum,
 186        .checksum_partial       = nf_ip6_checksum_partial,
 187        .route                  = nf_ip6_route,
 188        .saveroute              = nf_ip6_saveroute,
 189        .reroute                = nf_ip6_reroute,
 190        .route_key_size         = sizeof(struct ip6_rt_info),
 191};
 192
 193int __init ipv6_netfilter_init(void)
 194{
 195        return nf_register_afinfo(&nf_ip6_afinfo);
 196}
 197
 198/* This can be called from inet6_init() on errors, so it cannot
 199 * be marked __exit. -DaveM
 200 */
 201void ipv6_netfilter_fini(void)
 202{
 203        nf_unregister_afinfo(&nf_ip6_afinfo);
 204}
 205
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.