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ed6c4136 PNA |
1 | /* |
2 | * Copyright (c) 2015 Pablo Neira Ayuso <pablo@netfilter.org> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | */ | |
8 | ||
9 | #include <linux/init.h> | |
10 | #include <linux/module.h> | |
835b8033 | 11 | #include <linux/netdevice.h> |
ed6c4136 PNA |
12 | #include <net/netfilter/nf_tables.h> |
13 | #include <linux/ip.h> | |
14 | #include <linux/ipv6.h> | |
15 | #include <net/netfilter/nf_tables_ipv4.h> | |
16 | #include <net/netfilter/nf_tables_ipv6.h> | |
17 | ||
18 | static inline void | |
19 | nft_netdev_set_pktinfo_ipv4(struct nft_pktinfo *pkt, | |
20 | const struct nf_hook_ops *ops, struct sk_buff *skb, | |
21 | const struct nf_hook_state *state) | |
22 | { | |
23 | struct iphdr *iph, _iph; | |
24 | u32 len, thoff; | |
25 | ||
26 | nft_set_pktinfo(pkt, ops, skb, state); | |
27 | ||
28 | iph = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*iph), | |
29 | &_iph); | |
30 | if (!iph) | |
31 | return; | |
32 | ||
33 | iph = ip_hdr(skb); | |
34 | if (iph->ihl < 5 || iph->version != 4) | |
35 | return; | |
36 | ||
37 | len = ntohs(iph->tot_len); | |
38 | thoff = iph->ihl * 4; | |
39 | if (skb->len < len) | |
40 | return; | |
41 | else if (len < thoff) | |
42 | return; | |
43 | ||
44 | pkt->tprot = iph->protocol; | |
45 | pkt->xt.thoff = thoff; | |
46 | pkt->xt.fragoff = ntohs(iph->frag_off) & IP_OFFSET; | |
47 | } | |
48 | ||
49 | static inline void | |
50 | __nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt, | |
51 | const struct nf_hook_ops *ops, | |
52 | struct sk_buff *skb, | |
53 | const struct nf_hook_state *state) | |
54 | { | |
55 | #if IS_ENABLED(CONFIG_IPV6) | |
56 | struct ipv6hdr *ip6h, _ip6h; | |
57 | unsigned int thoff = 0; | |
58 | unsigned short frag_off; | |
59 | int protohdr; | |
60 | u32 pkt_len; | |
61 | ||
62 | ip6h = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*ip6h), | |
63 | &_ip6h); | |
64 | if (!ip6h) | |
65 | return; | |
66 | ||
67 | if (ip6h->version != 6) | |
68 | return; | |
69 | ||
70 | pkt_len = ntohs(ip6h->payload_len); | |
71 | if (pkt_len + sizeof(*ip6h) > skb->len) | |
72 | return; | |
73 | ||
74 | protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, NULL); | |
75 | if (protohdr < 0) | |
76 | return; | |
77 | ||
78 | pkt->tprot = protohdr; | |
79 | pkt->xt.thoff = thoff; | |
80 | pkt->xt.fragoff = frag_off; | |
81 | #endif | |
82 | } | |
83 | ||
84 | static inline void nft_netdev_set_pktinfo_ipv6(struct nft_pktinfo *pkt, | |
85 | const struct nf_hook_ops *ops, | |
86 | struct sk_buff *skb, | |
87 | const struct nf_hook_state *state) | |
88 | { | |
89 | nft_set_pktinfo(pkt, ops, skb, state); | |
90 | __nft_netdev_set_pktinfo_ipv6(pkt, ops, skb, state); | |
91 | } | |
92 | ||
93 | static unsigned int | |
94 | nft_do_chain_netdev(const struct nf_hook_ops *ops, struct sk_buff *skb, | |
95 | const struct nf_hook_state *state) | |
96 | { | |
97 | struct nft_pktinfo pkt; | |
98 | ||
99 | switch (eth_hdr(skb)->h_proto) { | |
100 | case htons(ETH_P_IP): | |
101 | nft_netdev_set_pktinfo_ipv4(&pkt, ops, skb, state); | |
102 | break; | |
103 | case htons(ETH_P_IPV6): | |
104 | nft_netdev_set_pktinfo_ipv6(&pkt, ops, skb, state); | |
105 | break; | |
106 | default: | |
107 | nft_set_pktinfo(&pkt, ops, skb, state); | |
108 | break; | |
109 | } | |
110 | ||
111 | return nft_do_chain(&pkt, ops); | |
112 | } | |
113 | ||
114 | static struct nft_af_info nft_af_netdev __read_mostly = { | |
115 | .family = NFPROTO_NETDEV, | |
116 | .nhooks = NF_NETDEV_NUMHOOKS, | |
117 | .owner = THIS_MODULE, | |
118 | .flags = NFT_AF_NEEDS_DEV, | |
119 | .nops = 1, | |
120 | .hooks = { | |
121 | [NF_NETDEV_INGRESS] = nft_do_chain_netdev, | |
122 | }, | |
123 | }; | |
124 | ||
125 | static int nf_tables_netdev_init_net(struct net *net) | |
126 | { | |
127 | net->nft.netdev = kmalloc(sizeof(struct nft_af_info), GFP_KERNEL); | |
128 | if (net->nft.netdev == NULL) | |
129 | return -ENOMEM; | |
130 | ||
131 | memcpy(net->nft.netdev, &nft_af_netdev, sizeof(nft_af_netdev)); | |
132 | ||
133 | if (nft_register_afinfo(net, net->nft.netdev) < 0) | |
134 | goto err; | |
135 | ||
136 | return 0; | |
137 | err: | |
138 | kfree(net->nft.netdev); | |
139 | return -ENOMEM; | |
140 | } | |
141 | ||
142 | static void nf_tables_netdev_exit_net(struct net *net) | |
143 | { | |
144 | nft_unregister_afinfo(net->nft.netdev); | |
145 | kfree(net->nft.netdev); | |
146 | } | |
147 | ||
148 | static struct pernet_operations nf_tables_netdev_net_ops = { | |
149 | .init = nf_tables_netdev_init_net, | |
150 | .exit = nf_tables_netdev_exit_net, | |
151 | }; | |
152 | ||
153 | static const struct nf_chain_type nft_filter_chain_netdev = { | |
154 | .name = "filter", | |
155 | .type = NFT_CHAIN_T_DEFAULT, | |
156 | .family = NFPROTO_NETDEV, | |
157 | .owner = THIS_MODULE, | |
158 | .hook_mask = (1 << NF_NETDEV_INGRESS), | |
159 | }; | |
160 | ||
835b8033 PNA |
161 | static void nft_netdev_event(unsigned long event, struct nft_af_info *afi, |
162 | struct net_device *dev, struct nft_table *table, | |
163 | struct nft_base_chain *basechain) | |
164 | { | |
165 | switch (event) { | |
166 | case NETDEV_REGISTER: | |
167 | if (strcmp(basechain->dev_name, dev->name) != 0) | |
168 | return; | |
169 | ||
170 | BUG_ON(!(basechain->flags & NFT_BASECHAIN_DISABLED)); | |
171 | ||
172 | dev_hold(dev); | |
173 | basechain->ops[0].dev = dev; | |
174 | basechain->flags &= ~NFT_BASECHAIN_DISABLED; | |
175 | if (!(table->flags & NFT_TABLE_F_DORMANT)) | |
176 | nft_register_basechain(basechain, afi->nops); | |
177 | break; | |
178 | case NETDEV_UNREGISTER: | |
179 | if (strcmp(basechain->dev_name, dev->name) != 0) | |
180 | return; | |
181 | ||
182 | BUG_ON(basechain->flags & NFT_BASECHAIN_DISABLED); | |
183 | ||
184 | if (!(table->flags & NFT_TABLE_F_DORMANT)) | |
185 | nft_unregister_basechain(basechain, afi->nops); | |
186 | ||
187 | dev_put(basechain->ops[0].dev); | |
188 | basechain->ops[0].dev = NULL; | |
189 | basechain->flags |= NFT_BASECHAIN_DISABLED; | |
190 | break; | |
191 | case NETDEV_CHANGENAME: | |
192 | if (dev->ifindex != basechain->ops[0].dev->ifindex) | |
193 | return; | |
194 | ||
195 | strncpy(basechain->dev_name, dev->name, IFNAMSIZ); | |
196 | break; | |
197 | } | |
198 | } | |
199 | ||
200 | static int nf_tables_netdev_event(struct notifier_block *this, | |
201 | unsigned long event, void *ptr) | |
202 | { | |
203 | struct net_device *dev = netdev_notifier_info_to_dev(ptr); | |
204 | struct nft_af_info *afi; | |
205 | struct nft_table *table; | |
206 | struct nft_chain *chain; | |
207 | ||
208 | nfnl_lock(NFNL_SUBSYS_NFTABLES); | |
209 | list_for_each_entry(afi, &dev_net(dev)->nft.af_info, list) { | |
210 | if (afi->family != NFPROTO_NETDEV) | |
211 | continue; | |
212 | ||
213 | list_for_each_entry(table, &afi->tables, list) { | |
214 | list_for_each_entry(chain, &table->chains, list) { | |
215 | if (!(chain->flags & NFT_BASE_CHAIN)) | |
216 | continue; | |
217 | ||
218 | nft_netdev_event(event, afi, dev, table, | |
219 | nft_base_chain(chain)); | |
220 | } | |
221 | } | |
222 | } | |
223 | nfnl_unlock(NFNL_SUBSYS_NFTABLES); | |
224 | ||
225 | return NOTIFY_DONE; | |
226 | } | |
227 | ||
228 | static struct notifier_block nf_tables_netdev_notifier = { | |
229 | .notifier_call = nf_tables_netdev_event, | |
230 | }; | |
231 | ||
ed6c4136 PNA |
232 | static int __init nf_tables_netdev_init(void) |
233 | { | |
234 | int ret; | |
235 | ||
236 | nft_register_chain_type(&nft_filter_chain_netdev); | |
237 | ret = register_pernet_subsys(&nf_tables_netdev_net_ops); | |
238 | if (ret < 0) | |
239 | nft_unregister_chain_type(&nft_filter_chain_netdev); | |
240 | ||
835b8033 PNA |
241 | register_netdevice_notifier(&nf_tables_netdev_notifier); |
242 | ||
ed6c4136 PNA |
243 | return ret; |
244 | } | |
245 | ||
246 | static void __exit nf_tables_netdev_exit(void) | |
247 | { | |
835b8033 | 248 | unregister_netdevice_notifier(&nf_tables_netdev_notifier); |
ed6c4136 PNA |
249 | unregister_pernet_subsys(&nf_tables_netdev_net_ops); |
250 | nft_unregister_chain_type(&nft_filter_chain_netdev); | |
251 | } | |
252 | ||
253 | module_init(nf_tables_netdev_init); | |
254 | module_exit(nf_tables_netdev_exit); | |
255 | ||
256 | MODULE_LICENSE("GPL"); | |
257 | MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>"); | |
258 | MODULE_ALIAS_NFT_FAMILY(5); /* NFPROTO_NETDEV */ |