target/linux/generic/backport-4.19/308-v4.16-netfilter-move-reroute-indirection-to-struct-nf_ipv6.patch

   1 From: Pablo Neira Ayuso <pablo@netfilter.org>
   2 Date: Mon, 27 Nov 2017 22:50:26 +0100
   3 Subject: [PATCH] netfilter: move reroute indirection to struct nf_ipv6_ops
   4
   5 We cannot make a direct call to nf_ip6_reroute() because that would result
   6 in autoloading the 'ipv6' module because of symbol dependencies.
   7 Therefore, define reroute indirection in nf_ipv6_ops where this really
   8 belongs to.
   9
  10 For IPv4, we can indeed make a direct function call, which is faster,
  11 given IPv4 is built-in in the networking code by default. Still,
  12 CONFIG_INET=n and CONFIG_NETFILTER=y is possible, so define empty inline
  13 stub for IPv4 in such case.
  14
  15 Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
  16 ---
  17
  18 --- a/include/linux/netfilter.h
  19 +++ b/include/linux/netfilter.h
  20 @@ -311,8 +311,6 @@ struct nf_queue_entry;
  21
  22  struct nf_afinfo {
  23         unsigned short  family;
  24 -       int             (*reroute)(struct net *net, struct sk_buff *skb,
  25 -                                  const struct nf_queue_entry *entry);
  26         int             route_key_size;
  27  };
  28
  29 @@ -331,6 +329,7 @@ __sum16 nf_checksum_partial(struct sk_bu
  30                             u_int8_t protocol, unsigned short family);
  31  int nf_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
  32              bool strict, unsigned short family);
  33 +int nf_reroute(struct sk_buff *skb, struct nf_queue_entry *entry);
  34
  35  int nf_register_afinfo(const struct nf_afinfo *afinfo);
  36  void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
  37 --- a/include/linux/netfilter_ipv4.h
  38 +++ b/include/linux/netfilter_ipv4.h
  39 @@ -18,6 +18,8 @@ struct ip_rt_info {
  40
  41  int ip_route_me_harder(struct net *net, struct sk_buff *skb, unsigned addr_type);
  42
  43 +struct nf_queue_entry;
  44 +
  45  #ifdef CONFIG_INET
  46  __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
  47                        unsigned int dataoff, u_int8_t protocol);
  48 @@ -26,6 +28,7 @@ __sum16 nf_ip_checksum_partial(struct sk
  49                                u_int8_t protocol);
  50  int nf_ip_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
  51                 bool strict);
  52 +int nf_ip_reroute(struct sk_buff *skb, const struct nf_queue_entry *entry);
  53  #else
  54  static inline __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
  55                                      unsigned int dataoff, u_int8_t protocol)
  56 @@ -45,6 +48,11 @@ static inline int nf_ip_route(struct net
  57  {
  58         return -EOPNOTSUPP;
  59  }
  60 +static inline int nf_ip_reroute(struct sk_buff *skb,
  61 +                               const struct nf_queue_entry *entry)
  62 +{
  63 +       return -EOPNOTSUPP;
  64 +}
  65  #endif /* CONFIG_INET */
  66
  67  #endif /*__LINUX_IP_NETFILTER_H*/
  68 --- a/include/linux/netfilter_ipv6.h
  69 +++ b/include/linux/netfilter_ipv6.h
  70 @@ -18,6 +18,8 @@ struct ip6_rt_info {
  71         u_int32_t mark;
  72  };
  73
  74 +struct nf_queue_entry;
  75 +
  76  /*
  77   * Hook functions for ipv6 to allow xt_* modules to be built-in even
  78   * if IPv6 is a module.
  79 @@ -35,6 +37,7 @@ struct nf_ipv6_ops {
  80                                     u_int8_t protocol);
  81         int (*route)(struct net *net, struct dst_entry **dst, struct flowi *fl,
  82                      bool strict);
  83 +       int (*reroute)(struct sk_buff *skb, const struct nf_queue_entry *entry);
  84  };
  85
  86  #ifdef CONFIG_NETFILTER
  87 --- a/net/bridge/netfilter/nf_tables_bridge.c
  88 +++ b/net/bridge/netfilter/nf_tables_bridge.c
  89 @@ -95,15 +95,8 @@ static const struct nf_chain_type filter
  90                           (1 << NF_BR_POST_ROUTING),
  91  };
  92
  93 -static int nf_br_reroute(struct net *net, struct sk_buff *skb,
  94 -                        const struct nf_queue_entry *entry)
  95 -{
  96 -       return 0;
  97 -}
  98 -
  99  static const struct nf_afinfo nf_br_afinfo = {
 100         .family                 = AF_BRIDGE,
 101 -       .reroute                = nf_br_reroute,
 102         .route_key_size         = 0,
 103  };
 104
 105 --- a/net/ipv4/netfilter.c
 106 +++ b/net/ipv4/netfilter.c
 107 @@ -80,8 +80,7 @@ int ip_route_me_harder(struct net *net,
 108  }
 109  EXPORT_SYMBOL(ip_route_me_harder);
 110
 111 -static int nf_ip_reroute(struct net *net, struct sk_buff *skb,
 112 -                        const struct nf_queue_entry *entry)
 113 +int nf_ip_reroute(struct sk_buff *skb, const struct nf_queue_entry *entry)
 114  {
 115         const struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
 116
 117 @@ -92,10 +91,12 @@ static int nf_ip_reroute(struct net *net
 118                       skb->mark == rt_info->mark &&
 119                       iph->daddr == rt_info->daddr &&
 120                       iph->saddr == rt_info->saddr))
 121 -                       return ip_route_me_harder(net, skb, RTN_UNSPEC);
 122 +                       return ip_route_me_harder(entry->state.net, skb,
 123 +                                                 RTN_UNSPEC);
 124         }
 125         return 0;
 126  }
 127 +EXPORT_SYMBOL_GPL(nf_ip_reroute);
 128
 129  __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
 130                             unsigned int dataoff, u_int8_t protocol)
 131 @@ -163,7 +164,6 @@ EXPORT_SYMBOL_GPL(nf_ip_route);
 132
 133  static const struct nf_afinfo nf_ip_afinfo = {
 134         .family                 = AF_INET,
 135 -       .reroute                = nf_ip_reroute,
 136         .route_key_size         = sizeof(struct ip_rt_info),
 137  };
 138
 139 --- a/net/ipv6/netfilter.c
 140 +++ b/net/ipv6/netfilter.c
 141 @@ -69,7 +69,7 @@ int ip6_route_me_harder(struct net *net,
 142  }
 143  EXPORT_SYMBOL(ip6_route_me_harder);
 144
 145 -static int nf_ip6_reroute(struct net *net, struct sk_buff *skb,
 146 +static int nf_ip6_reroute(struct sk_buff *skb,
 147                           const struct nf_queue_entry *entry)
 148  {
 149         struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
 150 @@ -79,7 +79,7 @@ static int nf_ip6_reroute(struct net *ne
 151                 if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) ||
 152                     !ipv6_addr_equal(&iph->saddr, &rt_info->saddr) ||
 153                     skb->mark != rt_info->mark)
 154 -                       return ip6_route_me_harder(net, skb);
 155 +                       return ip6_route_me_harder(entry->state.net, skb);
 156         }
 157         return 0;
 158  }
 159 @@ -172,11 +172,11 @@ static const struct nf_ipv6_ops ipv6ops
 160         .checksum               = nf_ip6_checksum,
 161         .checksum_partial       = nf_ip6_checksum_partial,
 162         .route                  = nf_ip6_route,
 163 +       .reroute                = nf_ip6_reroute,
 164  };
 165
 166  static const struct nf_afinfo nf_ip6_afinfo = {
 167         .family                 = AF_INET6,
 168 -       .reroute                = nf_ip6_reroute,
 169         .route_key_size         = sizeof(struct ip6_rt_info),
 170  };
 171
 172 --- a/net/netfilter/nf_queue.c
 173 +++ b/net/netfilter/nf_queue.c
 174 @@ -266,7 +266,6 @@ void nf_reinject(struct nf_queue_entry *
 175         const struct nf_hook_entry *hook_entry;
 176         const struct nf_hook_entries *hooks;
 177         struct sk_buff *skb = entry->skb;
 178 -       const struct nf_afinfo *afinfo;
 179         const struct net *net;
 180         unsigned int i;
 181         int err;
 182 @@ -293,8 +292,7 @@ void nf_reinject(struct nf_queue_entry *
 183                 verdict = nf_hook_entry_hookfn(hook_entry, skb, &entry->state);
 184
 185         if (verdict == NF_ACCEPT) {
 186 -               afinfo = nf_get_afinfo(entry->state.pf);
 187 -               if (!afinfo || afinfo->reroute(entry->state.net, skb, entry) < 0)
 188 +               if (nf_reroute(skb, entry) < 0)
 189                         verdict = NF_DROP;
 190         }
 191
 192 --- a/net/netfilter/utils.c
 193 +++ b/net/netfilter/utils.c
 194 @@ -2,6 +2,7 @@
 195  #include <linux/netfilter.h>
 196  #include <linux/netfilter_ipv4.h>
 197  #include <linux/netfilter_ipv6.h>
 198 +#include <net/netfilter/nf_queue.h>
 199
 200  __sum16 nf_checksum(struct sk_buff *skb, unsigned int hook,
 201                     unsigned int dataoff, u_int8_t protocol,
 202 @@ -69,3 +70,21 @@ int nf_route(struct net *net, struct dst
 203         return ret;
 204  }
 205  EXPORT_SYMBOL_GPL(nf_route);
 206 +
 207 +int nf_reroute(struct sk_buff *skb, struct nf_queue_entry *entry)
 208 +{
 209 +       const struct nf_ipv6_ops *v6ops;
 210 +       int ret = 0;
 211 +
 212 +       switch (entry->state.pf) {
 213 +       case AF_INET:
 214 +               ret = nf_ip_reroute(skb, entry);
 215 +               break;
 216 +       case AF_INET6:
 217 +               v6ops = rcu_dereference(nf_ipv6_ops);
 218 +               if (v6ops)
 219 +                       ret = v6ops->reroute(skb, entry);
 220 +               break;
 221 +       }
 222 +       return ret;
 223 +}