netfilter_bridge.h

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#ifndef __LINUX_BRIDGE_NETFILTER_H
#define __LINUX_BRIDGE_NETFILTER_H

#include <uapi/linux/netfilter_bridge.h>


enum nf_br_hook_priorities {
    NF_BR_PRI_FIRST = INT_MIN,
    NF_BR_PRI_NAT_DST_BRIDGED = -300,
    NF_BR_PRI_FILTER_BRIDGED = -200,
    NF_BR_PRI_BRNF = 0,
    NF_BR_PRI_NAT_DST_OTHER = 100,
    NF_BR_PRI_FILTER_OTHER = 200,
    NF_BR_PRI_NAT_SRC = 300,
    NF_BR_PRI_LAST = INT_MAX,
};

#ifdef CONFIG_BRIDGE_NETFILTER

#define BRNF_PKT_TYPE           0x01
#define BRNF_BRIDGED_DNAT       0x02
#define BRNF_BRIDGED            0x04
#define BRNF_NF_BRIDGE_PREROUTING   0x08
#define BRNF_8021Q          0x10
#define BRNF_PPPoE          0x20

/* Only used in br_forward.c */
extern int nf_bridge_copy_header(struct sk_buff *skb);
static inline int nf_bridge_maybe_copy_header(struct sk_buff *skb)
{
    if (skb->nf_bridge &&
        skb->nf_bridge->mask & (BRNF_BRIDGED | BRNF_BRIDGED_DNAT))
        return nf_bridge_copy_header(skb);
    return 0;
}

static inline unsigned int nf_bridge_encap_header_len(const struct sk_buff *skb)
{
    switch (skb->protocol) {
    case __cpu_to_be16(ETH_P_8021Q):
        return VLAN_HLEN;
    case __cpu_to_be16(ETH_P_PPP_SES):
        return PPPOE_SES_HLEN;
    default:
        return 0;
    }
}

static inline unsigned int nf_bridge_mtu_reduction(const struct sk_buff *skb)
{
    if (unlikely(skb->nf_bridge->mask & BRNF_PPPoE))
        return PPPOE_SES_HLEN;
    return 0;
}

extern int br_handle_frame_finish(struct sk_buff *skb);
/* Only used in br_device.c */
static inline int br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb)
{
    struct nf_bridge_info *nf_bridge = skb->nf_bridge;

    skb_pull(skb, ETH_HLEN);
    nf_bridge->mask ^= BRNF_BRIDGED_DNAT;
    skb_copy_to_linear_data_offset(skb, -(ETH_HLEN-ETH_ALEN),
                       skb->nf_bridge->data, ETH_HLEN-ETH_ALEN);
    skb->dev = nf_bridge->physindev;
    return br_handle_frame_finish(skb);
}

/* This is called by the IP fragmenting code and it ensures there is
 * enough room for the encapsulating header (if there is one). */
static inline unsigned int nf_bridge_pad(const struct sk_buff *skb)
{
    if (skb->nf_bridge)
        return nf_bridge_encap_header_len(skb);
    return 0;
}

struct bridge_skb_cb {
    union {
        __be32 ipv4;
    } daddr;
};

static inline void br_drop_fake_rtable(struct sk_buff *skb)
{
    struct dst_entry *dst = skb_dst(skb);

    if (dst && (dst->flags & DST_FAKE_RTABLE))
        skb_dst_drop(skb);
}

#else
#define nf_bridge_maybe_copy_header(skb)    (0)
#define nf_bridge_pad(skb)          (0)
#define br_drop_fake_rtable(skb)            do { } while (0)
#endif /* CONFIG_BRIDGE_NETFILTER */

#endif