1 // SPDX-License-Identifier: GPL-2.0-only
2
3 #include <linux/kernel.h>
4 #include <linux/init.h>
5 #include <linux/module.h>
6 #include <linux/netlink.h>
7 #include <linux/netfilter.h>
8 #include <linux/netfilter/nf_tables.h>
9 #include <linux/netfilter_ipv6.h>
10 #include <net/netfilter/nf_tables_core.h>
11 #include <net/netfilter/nf_tables.h>
12 #include <net/netfilter/nft_fib.h>
13
14 #include <net/ip6_fib.h>
15 #include <net/ip6_route.h>
16
get_ifindex(const struct net_device * dev)17 static int get_ifindex(const struct net_device *dev)
18 {
19 return dev ? dev->ifindex : 0;
20 }
21
nft_fib6_flowi_init(struct flowi6 * fl6,const struct nft_fib * priv,const struct nft_pktinfo * pkt,const struct net_device * dev,struct ipv6hdr * iph)22 static int nft_fib6_flowi_init(struct flowi6 *fl6, const struct nft_fib *priv,
23 const struct nft_pktinfo *pkt,
24 const struct net_device *dev,
25 struct ipv6hdr *iph)
26 {
27 int lookup_flags = 0;
28
29 if (priv->flags & NFTA_FIB_F_DADDR) {
30 fl6->daddr = iph->daddr;
31 fl6->saddr = iph->saddr;
32 } else {
33 fl6->daddr = iph->saddr;
34 fl6->saddr = iph->daddr;
35 }
36
37 if (ipv6_addr_type(&fl6->daddr) & IPV6_ADDR_LINKLOCAL) {
38 lookup_flags |= RT6_LOOKUP_F_IFACE;
39 fl6->flowi6_oif = get_ifindex(dev ? dev : pkt->skb->dev);
40 } else if ((priv->flags & NFTA_FIB_F_IIF) &&
41 (netif_is_l3_master(dev) || netif_is_l3_slave(dev))) {
42 fl6->flowi6_oif = dev->ifindex;
43 }
44
45 if (ipv6_addr_type(&fl6->saddr) & IPV6_ADDR_UNICAST)
46 lookup_flags |= RT6_LOOKUP_F_HAS_SADDR;
47
48 if (priv->flags & NFTA_FIB_F_MARK)
49 fl6->flowi6_mark = pkt->skb->mark;
50
51 fl6->flowlabel = (*(__be32 *)iph) & IPV6_FLOWINFO_MASK;
52
53 return lookup_flags;
54 }
55
__nft_fib6_eval_type(const struct nft_fib * priv,const struct nft_pktinfo * pkt,struct ipv6hdr * iph)56 static u32 __nft_fib6_eval_type(const struct nft_fib *priv,
57 const struct nft_pktinfo *pkt,
58 struct ipv6hdr *iph)
59 {
60 const struct net_device *dev = NULL;
61 int route_err, addrtype;
62 struct rt6_info *rt;
63 struct flowi6 fl6 = {
64 .flowi6_iif = LOOPBACK_IFINDEX,
65 .flowi6_proto = pkt->tprot,
66 };
67 u32 ret = 0;
68
69 if (priv->flags & NFTA_FIB_F_IIF)
70 dev = nft_in(pkt);
71 else if (priv->flags & NFTA_FIB_F_OIF)
72 dev = nft_out(pkt);
73
74 nft_fib6_flowi_init(&fl6, priv, pkt, dev, iph);
75
76 if (dev && nf_ipv6_chk_addr(nft_net(pkt), &fl6.daddr, dev, true))
77 ret = RTN_LOCAL;
78
79 route_err = nf_ip6_route(nft_net(pkt), (struct dst_entry **)&rt,
80 flowi6_to_flowi(&fl6), false);
81 if (route_err)
82 goto err;
83
84 if (rt->rt6i_flags & RTF_REJECT) {
85 route_err = rt->dst.error;
86 dst_release(&rt->dst);
87 goto err;
88 }
89
90 if (ipv6_anycast_destination((struct dst_entry *)rt, &fl6.daddr))
91 ret = RTN_ANYCAST;
92 else if (!dev && rt->rt6i_flags & RTF_LOCAL)
93 ret = RTN_LOCAL;
94
95 dst_release(&rt->dst);
96
97 if (ret)
98 return ret;
99
100 addrtype = ipv6_addr_type(&fl6.daddr);
101
102 if (addrtype & IPV6_ADDR_MULTICAST)
103 return RTN_MULTICAST;
104 if (addrtype & IPV6_ADDR_UNICAST)
105 return RTN_UNICAST;
106
107 return RTN_UNSPEC;
108 err:
109 switch (route_err) {
110 case -EINVAL:
111 return RTN_BLACKHOLE;
112 case -EACCES:
113 return RTN_PROHIBIT;
114 case -EAGAIN:
115 return RTN_THROW;
116 default:
117 break;
118 }
119
120 return RTN_UNREACHABLE;
121 }
122
nft_fib6_eval_type(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)123 void nft_fib6_eval_type(const struct nft_expr *expr, struct nft_regs *regs,
124 const struct nft_pktinfo *pkt)
125 {
126 const struct nft_fib *priv = nft_expr_priv(expr);
127 int noff = skb_network_offset(pkt->skb);
128 u32 *dest = ®s->data[priv->dreg];
129 struct ipv6hdr *iph, _iph;
130
131 iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
132 if (!iph) {
133 regs->verdict.code = NFT_BREAK;
134 return;
135 }
136
137 *dest = __nft_fib6_eval_type(priv, pkt, iph);
138 }
139 EXPORT_SYMBOL_GPL(nft_fib6_eval_type);
140
nft_fib_v6_skip_icmpv6(const struct sk_buff * skb,u8 next,const struct ipv6hdr * iph)141 static bool nft_fib_v6_skip_icmpv6(const struct sk_buff *skb, u8 next, const struct ipv6hdr *iph)
142 {
143 if (likely(next != IPPROTO_ICMPV6))
144 return false;
145
146 if (ipv6_addr_type(&iph->saddr) != IPV6_ADDR_ANY)
147 return false;
148
149 return ipv6_addr_type(&iph->daddr) & IPV6_ADDR_LINKLOCAL;
150 }
151
nft_fib6_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)152 void nft_fib6_eval(const struct nft_expr *expr, struct nft_regs *regs,
153 const struct nft_pktinfo *pkt)
154 {
155 const struct nft_fib *priv = nft_expr_priv(expr);
156 int noff = skb_network_offset(pkt->skb);
157 const struct net_device *oif = NULL;
158 u32 *dest = ®s->data[priv->dreg];
159 struct ipv6hdr *iph, _iph;
160 struct flowi6 fl6 = {
161 .flowi6_iif = LOOPBACK_IFINDEX,
162 .flowi6_proto = pkt->tprot,
163 };
164 struct rt6_info *rt;
165 int lookup_flags;
166
167 if (priv->flags & NFTA_FIB_F_IIF)
168 oif = nft_in(pkt);
169 else if (priv->flags & NFTA_FIB_F_OIF)
170 oif = nft_out(pkt);
171
172 iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
173 if (!iph) {
174 regs->verdict.code = NFT_BREAK;
175 return;
176 }
177
178 lookup_flags = nft_fib6_flowi_init(&fl6, priv, pkt, oif, iph);
179
180 if (nft_hook(pkt) == NF_INET_PRE_ROUTING ||
181 nft_hook(pkt) == NF_INET_INGRESS) {
182 if (nft_fib_is_loopback(pkt->skb, nft_in(pkt)) ||
183 nft_fib_v6_skip_icmpv6(pkt->skb, pkt->tprot, iph)) {
184 nft_fib_store_result(dest, priv, nft_in(pkt));
185 return;
186 }
187 }
188
189 *dest = 0;
190 rt = (void *)ip6_route_lookup(nft_net(pkt), &fl6, pkt->skb,
191 lookup_flags);
192 if (rt->dst.error)
193 goto put_rt_err;
194
195 /* Should not see RTF_LOCAL here */
196 if (rt->rt6i_flags & (RTF_REJECT | RTF_ANYCAST | RTF_LOCAL))
197 goto put_rt_err;
198
199 if (oif && oif != rt->rt6i_idev->dev &&
200 l3mdev_master_ifindex_rcu(rt->rt6i_idev->dev) != oif->ifindex)
201 goto put_rt_err;
202
203 nft_fib_store_result(dest, priv, rt->rt6i_idev->dev);
204 put_rt_err:
205 ip6_rt_put(rt);
206 }
207 EXPORT_SYMBOL_GPL(nft_fib6_eval);
208
209 static struct nft_expr_type nft_fib6_type;
210
211 static const struct nft_expr_ops nft_fib6_type_ops = {
212 .type = &nft_fib6_type,
213 .size = NFT_EXPR_SIZE(sizeof(struct nft_fib)),
214 .eval = nft_fib6_eval_type,
215 .init = nft_fib_init,
216 .dump = nft_fib_dump,
217 .validate = nft_fib_validate,
218 };
219
220 static const struct nft_expr_ops nft_fib6_ops = {
221 .type = &nft_fib6_type,
222 .size = NFT_EXPR_SIZE(sizeof(struct nft_fib)),
223 .eval = nft_fib6_eval,
224 .init = nft_fib_init,
225 .dump = nft_fib_dump,
226 .validate = nft_fib_validate,
227 };
228
229 static const struct nft_expr_ops *
nft_fib6_select_ops(const struct nft_ctx * ctx,const struct nlattr * const tb[])230 nft_fib6_select_ops(const struct nft_ctx *ctx,
231 const struct nlattr * const tb[])
232 {
233 enum nft_fib_result result;
234
235 if (!tb[NFTA_FIB_RESULT])
236 return ERR_PTR(-EINVAL);
237
238 result = ntohl(nla_get_be32(tb[NFTA_FIB_RESULT]));
239
240 switch (result) {
241 case NFT_FIB_RESULT_OIF:
242 return &nft_fib6_ops;
243 case NFT_FIB_RESULT_OIFNAME:
244 return &nft_fib6_ops;
245 case NFT_FIB_RESULT_ADDRTYPE:
246 return &nft_fib6_type_ops;
247 default:
248 return ERR_PTR(-EOPNOTSUPP);
249 }
250 }
251
252 static struct nft_expr_type nft_fib6_type __read_mostly = {
253 .name = "fib",
254 .select_ops = nft_fib6_select_ops,
255 .policy = nft_fib_policy,
256 .maxattr = NFTA_FIB_MAX,
257 .family = NFPROTO_IPV6,
258 .owner = THIS_MODULE,
259 };
260
nft_fib6_module_init(void)261 static int __init nft_fib6_module_init(void)
262 {
263 return nft_register_expr(&nft_fib6_type);
264 }
265
nft_fib6_module_exit(void)266 static void __exit nft_fib6_module_exit(void)
267 {
268 nft_unregister_expr(&nft_fib6_type);
269 }
270 module_init(nft_fib6_module_init);
271 module_exit(nft_fib6_module_exit);
272
273 MODULE_LICENSE("GPL");
274 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
275 MODULE_ALIAS_NFT_AF_EXPR(10, "fib");
276 MODULE_DESCRIPTION("nftables fib / ipv6 route lookup support");
277