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
fake_update_pmtu(struct dst_entry * dst,struct sock * sk,struct sk_buff * skb,u32 mtu)24 static void fake_update_pmtu(struct dst_entry *dst, struct sock *sk,
25 struct sk_buff *skb, u32 mtu)
26 {
27 }
28
fake_redirect(struct dst_entry * dst,struct sock * sk,struct sk_buff * skb)29 static void fake_redirect(struct dst_entry *dst, struct sock *sk,
30 struct sk_buff *skb)
31 {
32 }
33
fake_cow_metrics(struct dst_entry * dst,unsigned long old)34 static u32 *fake_cow_metrics(struct dst_entry *dst, unsigned long old)
35 {
36 return NULL;
37 }
38
fake_neigh_lookup(const struct dst_entry * dst,struct sk_buff * skb,const void * daddr)39 static struct neighbour *fake_neigh_lookup(const struct dst_entry *dst,
40 struct sk_buff *skb,
41 const void *daddr)
42 {
43 return NULL;
44 }
45
fake_mtu(const struct dst_entry * dst)46 static unsigned int fake_mtu(const struct dst_entry *dst)
47 {
48 return dst->dev->mtu;
49 }
50
51 static struct dst_ops fake_dst_ops = {
52 .family = AF_INET,
53 .update_pmtu = fake_update_pmtu,
54 .redirect = fake_redirect,
55 .cow_metrics = fake_cow_metrics,
56 .neigh_lookup = fake_neigh_lookup,
57 .mtu = fake_mtu,
58 };
59
60 /*
61 * Initialize bogus route table used to keep netfilter happy.
62 * Currently, we fill in the PMTU entry because netfilter
63 * refragmentation needs it, and the rt_flags entry because
64 * ipt_REJECT needs it. Future netfilter modules might
65 * require us to fill additional fields.
66 */
67 static const u32 br_dst_default_metrics[RTAX_MAX] = {
68 [RTAX_MTU - 1] = 1500,
69 };
70
br_netfilter_rtable_init(struct net_bridge * br)71 void br_netfilter_rtable_init(struct net_bridge *br)
72 {
73 struct rtable *rt = &br->fake_rtable;
74
75 atomic_set(&rt->dst.__refcnt, 1);
76 rt->dst.dev = br->dev;
77 dst_init_metrics(&rt->dst, br_dst_default_metrics, true);
78 rt->dst.flags = DST_NOXFRM | DST_FAKE_RTABLE;
79 rt->dst.ops = &fake_dst_ops;
80 }
81
br_nf_core_init(void)82 int __init br_nf_core_init(void)
83 {
84 return dst_entries_init(&fake_dst_ops);
85 }
86
br_nf_core_fini(void)87 void br_nf_core_fini(void)
88 {
89 dst_entries_destroy(&fake_dst_ops);
90 }
91
