LXR linux/net/bridge/br_nf

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *      Handle firewalling core
   4 *      Linux ethernet bridge
   5 *
   6 *      Authors:
   7 *      Lennert Buytenhek               <buytenh@gnu.org>
   8 *      Bart De Schuymer                <bdschuym@pandora.be>
   9 *
  10 *      Lennert dedicates this file to Kerstin Wurdinger.
  11 */
  12
  13#include <linux/module.h>
  14#include <linux/kernel.h>
  15#include <linux/in_route.h>
  16#include <linux/inetdevice.h>
  17#include <net/route.h>
  18
  19#include "br_private.h"
  20#ifdef CONFIG_SYSCTL
  21#include <linux/sysctl.h>
  22#endif
  23
  24static void fake_update_pmtu(struct dst_entry *dst, struct sock *sk,
  25                             struct sk_buff *skb, u32 mtu,
  26                             bool confirm_neigh)
  27{
  28}
  29
  30static void fake_redirect(struct dst_entry *dst, struct sock *sk,
  31                          struct sk_buff *skb)
  32{
  33}
  34
  35static u32 *fake_cow_metrics(struct dst_entry *dst, unsigned long old)
  36{
  37        return NULL;
  38}
  39
  40static struct neighbour *fake_neigh_lookup(const struct dst_entry *dst,
  41                                           struct sk_buff *skb,
  42                                           const void *daddr)
  43{
  44        return NULL;
  45}
  46
  47static unsigned int fake_mtu(const struct dst_entry *dst)
  48{
  49        return dst->dev->mtu;
  50}
  51
  52static struct dst_ops fake_dst_ops = {
  53        .family         = AF_INET,
  54        .update_pmtu    = fake_update_pmtu,
  55        .redirect       = fake_redirect,
  56        .cow_metrics    = fake_cow_metrics,
  57        .neigh_lookup   = fake_neigh_lookup,
  58        .mtu            = fake_mtu,
  59};
  60
  61/*
  62 * Initialize bogus route table used to keep netfilter happy.
  63 * Currently, we fill in the PMTU entry because netfilter
  64 * refragmentation needs it, and the rt_flags entry because
  65 * ipt_REJECT needs it.  Future netfilter modules might
  66 * require us to fill additional fields.
  67 */
  68static const u32 br_dst_default_metrics[RTAX_MAX] = {
  69        [RTAX_MTU - 1] = 1500,
  70};
  71
  72void br_netfilter_rtable_init(struct net_bridge *br)
  73{
  74        struct rtable *rt = &br->fake_rtable;
  75
  76        atomic_set(&rt->dst.__refcnt, 1);
  77        rt->dst.dev = br->dev;
  78        dst_init_metrics(&rt->dst, br_dst_default_metrics, true);
  79        rt->dst.flags   = DST_NOXFRM | DST_FAKE_RTABLE;
  80        rt->dst.ops = &fake_dst_ops;
  81}
  82
  83int __init br_nf_core_init(void)
  84{
  85        return dst_entries_init(&fake_dst_ops);
  86}
  87
  88void br_nf_core_fini(void)
  89{
  90        dst_entries_destroy(&fake_dst_ops);
  91}
  92