1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (c) 2014 Pablo Neira Ayuso <pablo@netfilter.org>
6 #include <linux/kernel.h>
7 #include <linux/init.h>
8 #include <linux/module.h>
9 #include <linux/netlink.h>
10 #include <linux/netfilter.h>
11 #include <linux/netfilter/nf_tables.h>
12 #include <net/netfilter/nf_tables.h>
13 #include <net/netfilter/nft_reject.h>
14 #include <net/netfilter/ipv4/nf_reject.h>
15 #include <net/netfilter/ipv6/nf_reject.h>
18 #include <net/ip6_checksum.h>
19 #include <linux/netfilter_bridge.h>
20 #include <linux/netfilter_ipv6.h>
21 #include "../br_private.h"
23 static void nft_reject_br_push_etherhdr(struct sk_buff *oldskb,
28 eth = skb_push(nskb, ETH_HLEN);
29 skb_reset_mac_header(nskb);
30 ether_addr_copy(eth->h_source, eth_hdr(oldskb)->h_dest);
31 ether_addr_copy(eth->h_dest, eth_hdr(oldskb)->h_source);
32 eth->h_proto = eth_hdr(oldskb)->h_proto;
33 skb_pull(nskb, ETH_HLEN);
35 if (skb_vlan_tag_present(oldskb)) {
36 u16 vid = skb_vlan_tag_get(oldskb);
38 __vlan_hwaccel_put_tag(nskb, oldskb->vlan_proto, vid);
42 /* We cannot use oldskb->dev, it can be either bridge device (NF_BRIDGE INPUT)
43 * or the bridge port (NF_BRIDGE PREROUTING).
45 static void nft_reject_br_send_v4_tcp_reset(struct net *net,
46 struct sk_buff *oldskb,
47 const struct net_device *dev,
52 nskb = nf_reject_skb_v4_tcp_reset(net, oldskb, dev, hook);
56 nft_reject_br_push_etherhdr(oldskb, nskb);
58 br_forward(br_port_get_rcu(dev), nskb, false, true);
61 static void nft_reject_br_send_v4_unreach(struct net *net,
62 struct sk_buff *oldskb,
63 const struct net_device *dev,
68 nskb = nf_reject_skb_v4_unreach(net, oldskb, dev, hook, code);
72 nft_reject_br_push_etherhdr(oldskb, nskb);
74 br_forward(br_port_get_rcu(dev), nskb, false, true);
77 static void nft_reject_br_send_v6_tcp_reset(struct net *net,
78 struct sk_buff *oldskb,
79 const struct net_device *dev,
84 nskb = nf_reject_skb_v6_tcp_reset(net, oldskb, dev, hook);
88 nft_reject_br_push_etherhdr(oldskb, nskb);
90 br_forward(br_port_get_rcu(dev), nskb, false, true);
94 static void nft_reject_br_send_v6_unreach(struct net *net,
95 struct sk_buff *oldskb,
96 const struct net_device *dev,
101 nskb = nf_reject_skb_v6_unreach(net, oldskb, dev, hook, code);
105 nft_reject_br_push_etherhdr(oldskb, nskb);
107 br_forward(br_port_get_rcu(dev), nskb, false, true);
110 static void nft_reject_bridge_eval(const struct nft_expr *expr,
111 struct nft_regs *regs,
112 const struct nft_pktinfo *pkt)
114 struct nft_reject *priv = nft_expr_priv(expr);
115 const unsigned char *dest = eth_hdr(pkt->skb)->h_dest;
117 if (is_broadcast_ether_addr(dest) ||
118 is_multicast_ether_addr(dest))
121 switch (eth_hdr(pkt->skb)->h_proto) {
122 case htons(ETH_P_IP):
123 switch (priv->type) {
124 case NFT_REJECT_ICMP_UNREACH:
125 nft_reject_br_send_v4_unreach(nft_net(pkt), pkt->skb,
130 case NFT_REJECT_TCP_RST:
131 nft_reject_br_send_v4_tcp_reset(nft_net(pkt), pkt->skb,
135 case NFT_REJECT_ICMPX_UNREACH:
136 nft_reject_br_send_v4_unreach(nft_net(pkt), pkt->skb,
139 nft_reject_icmp_code(priv->icmp_code));
143 case htons(ETH_P_IPV6):
144 switch (priv->type) {
145 case NFT_REJECT_ICMP_UNREACH:
146 nft_reject_br_send_v6_unreach(nft_net(pkt), pkt->skb,
151 case NFT_REJECT_TCP_RST:
152 nft_reject_br_send_v6_tcp_reset(nft_net(pkt), pkt->skb,
156 case NFT_REJECT_ICMPX_UNREACH:
157 nft_reject_br_send_v6_unreach(nft_net(pkt), pkt->skb,
160 nft_reject_icmpv6_code(priv->icmp_code));
165 /* No explicit way to reject this protocol, drop it. */
169 regs->verdict.code = NF_DROP;
172 static int nft_reject_bridge_validate(const struct nft_ctx *ctx,
173 const struct nft_expr *expr,
174 const struct nft_data **data)
176 return nft_chain_validate_hooks(ctx->chain, (1 << NF_BR_PRE_ROUTING) |
177 (1 << NF_BR_LOCAL_IN));
180 static struct nft_expr_type nft_reject_bridge_type;
181 static const struct nft_expr_ops nft_reject_bridge_ops = {
182 .type = &nft_reject_bridge_type,
183 .size = NFT_EXPR_SIZE(sizeof(struct nft_reject)),
184 .eval = nft_reject_bridge_eval,
185 .init = nft_reject_init,
186 .dump = nft_reject_dump,
187 .validate = nft_reject_bridge_validate,
190 static struct nft_expr_type nft_reject_bridge_type __read_mostly = {
191 .family = NFPROTO_BRIDGE,
193 .ops = &nft_reject_bridge_ops,
194 .policy = nft_reject_policy,
195 .maxattr = NFTA_REJECT_MAX,
196 .owner = THIS_MODULE,
199 static int __init nft_reject_bridge_module_init(void)
201 return nft_register_expr(&nft_reject_bridge_type);
204 static void __exit nft_reject_bridge_module_exit(void)
206 nft_unregister_expr(&nft_reject_bridge_type);
209 module_init(nft_reject_bridge_module_init);
210 module_exit(nft_reject_bridge_module_exit);
212 MODULE_LICENSE("GPL");
213 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
214 MODULE_ALIAS_NFT_AF_EXPR(AF_BRIDGE, "reject");
215 MODULE_DESCRIPTION("Reject packets from bridge via nftables");