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 | |
24 | static 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 | |
30 | static void fake_redirect(struct dst_entry *dst, struct sock *sk, |
31 | struct sk_buff *skb) |
32 | { |
33 | } |
34 | |
35 | static u32 *fake_cow_metrics(struct dst_entry *dst, unsigned long old) |
36 | { |
37 | return NULL; |
38 | } |
39 | |
40 | static 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 | |
47 | static unsigned int fake_mtu(const struct dst_entry *dst) |
48 | { |
49 | return dst->dev->mtu; |
50 | } |
51 | |
52 | static 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 | */ |
68 | static const u32 br_dst_default_metrics[RTAX_MAX] = { |
69 | [RTAX_MTU - 1] = 1500, |
70 | }; |
71 | |
72 | void br_netfilter_rtable_init(struct net_bridge *br) |
73 | { |
74 | struct rtable *rt = &br->fake_rtable; |
75 | |
76 | rcuref_init(ref: &rt->dst.__rcuref, cnt: 1); |
77 | rt->dst.dev = br->dev; |
78 | dst_init_metrics(dst: &rt->dst, src_metrics: br_dst_default_metrics, read_only: true); |
79 | rt->dst.flags = DST_NOXFRM | DST_FAKE_RTABLE; |
80 | rt->dst.ops = &fake_dst_ops; |
81 | } |
82 | |
83 | int __init br_nf_core_init(void) |
84 | { |
85 | return dst_entries_init(dst: &fake_dst_ops); |
86 | } |
87 | |
88 | void br_nf_core_fini(void) |
89 | { |
90 | dst_entries_destroy(dst: &fake_dst_ops); |
91 | } |
92 | |