include/linux/netfilter_bridge.h

   1 #ifndef __LINUX_BRIDGE_NETFILTER_H
   2 #define __LINUX_BRIDGE_NETFILTER_H
   3
   4 #include <uapi/linux/netfilter_bridge.h>
   5
   6
   7 enum nf_br_hook_priorities {
   8         NF_BR_PRI_FIRST = INT_MIN,
   9         NF_BR_PRI_NAT_DST_BRIDGED = -300,
  10         NF_BR_PRI_FILTER_BRIDGED = -200,
  11         NF_BR_PRI_BRNF = 0,
  12         NF_BR_PRI_NAT_DST_OTHER = 100,
  13         NF_BR_PRI_FILTER_OTHER = 200,
  14         NF_BR_PRI_NAT_SRC = 300,
  15         NF_BR_PRI_LAST = INT_MAX,
  16 };
  17
  18 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
  19
  20 #define BRNF_PKT_TYPE                   0x01
  21 #define BRNF_BRIDGED_DNAT               0x02
  22 #define BRNF_BRIDGED                    0x04
  23 #define BRNF_NF_BRIDGE_PREROUTING       0x08
  24 #define BRNF_8021Q                      0x10
  25 #define BRNF_PPPoE                      0x20
  26
  27 static inline unsigned int nf_bridge_encap_header_len(const struct sk_buff *skb)
  28 {
  29         switch (skb->protocol) {
  30         case __cpu_to_be16(ETH_P_8021Q):
  31                 return VLAN_HLEN;
  32         case __cpu_to_be16(ETH_P_PPP_SES):
  33                 return PPPOE_SES_HLEN;
  34         default:
  35                 return 0;
  36         }
  37 }
  38
  39 static inline void nf_bridge_update_protocol(struct sk_buff *skb)
  40 {
  41         if (skb->nf_bridge->mask & BRNF_8021Q)
  42                 skb->protocol = htons(ETH_P_8021Q);
  43         else if (skb->nf_bridge->mask & BRNF_PPPoE)
  44                 skb->protocol = htons(ETH_P_PPP_SES);
  45 }
  46
  47 /* Fill in the header for fragmented IP packets handled by
  48  * the IPv4 connection tracking code.
  49  *
  50  * Only used in br_forward.c
  51  */
  52 static inline int nf_bridge_copy_header(struct sk_buff *skb)
  53 {
  54         int err;
  55         unsigned int header_size;
  56
  57         nf_bridge_update_protocol(skb);
  58         header_size = ETH_HLEN + nf_bridge_encap_header_len(skb);
  59         err = skb_cow_head(skb, header_size);
  60         if (err)
  61                 return err;
  62
  63         skb_copy_to_linear_data_offset(skb, -header_size,
  64                                        skb->nf_bridge->data, header_size);
  65         __skb_push(skb, nf_bridge_encap_header_len(skb));
  66         return 0;
  67 }
  68
  69 static inline int nf_bridge_maybe_copy_header(struct sk_buff *skb)
  70 {
  71         if (skb->nf_bridge &&
  72             skb->nf_bridge->mask & (BRNF_BRIDGED | BRNF_BRIDGED_DNAT))
  73                 return nf_bridge_copy_header(skb);
  74         return 0;
  75 }
  76
  77 static inline unsigned int nf_bridge_mtu_reduction(const struct sk_buff *skb)
  78 {
  79         if (unlikely(skb->nf_bridge->mask & BRNF_PPPoE))
  80                 return PPPOE_SES_HLEN;
  81         return 0;
  82 }
  83
  84 int br_handle_frame_finish(struct sk_buff *skb);
  85 /* Only used in br_device.c */
  86 static inline int br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb)
  87 {
  88         struct nf_bridge_info *nf_bridge = skb->nf_bridge;
  89
  90         skb_pull(skb, ETH_HLEN);
  91         nf_bridge->mask ^= BRNF_BRIDGED_DNAT;
  92         skb_copy_to_linear_data_offset(skb, -(ETH_HLEN-ETH_ALEN),
  93                                        skb->nf_bridge->data, ETH_HLEN-ETH_ALEN);
  94         skb->dev = nf_bridge->physindev;
  95         return br_handle_frame_finish(skb);
  96 }
  97
  98 /* This is called by the IP fragmenting code and it ensures there is
  99  * enough room for the encapsulating header (if there is one). */
 100 static inline unsigned int nf_bridge_pad(const struct sk_buff *skb)
 101 {
 102         if (skb->nf_bridge)
 103                 return nf_bridge_encap_header_len(skb);
 104         return 0;
 105 }
 106
 107 struct bridge_skb_cb {
 108         union {
 109                 __be32 ipv4;
 110         } daddr;
 111 };
 112
 113 static inline void br_drop_fake_rtable(struct sk_buff *skb)
 114 {
 115         struct dst_entry *dst = skb_dst(skb);
 116
 117         if (dst && (dst->flags & DST_FAKE_RTABLE))
 118                 skb_dst_drop(skb);
 119 }
 120
 121 #else
 122 #define nf_bridge_maybe_copy_header(skb)        (0)
 123 #define nf_bridge_pad(skb)                      (0)
 124 #define br_drop_fake_rtable(skb)                do { } while (0)
 125 #endif /* CONFIG_BRIDGE_NETFILTER */
 126
 127 #endif