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 if (nft_hook(pkt) == NF_INET_FORWARD &&
34 priv->flags & NFTA_FIB_F_IIF)
35 fl6->flowi6_iif = nft_out(pkt)->ifindex;
36
37 fl6->daddr = iph->saddr;
38 fl6->saddr = iph->daddr;
39 }
40
41 if (ipv6_addr_type(&fl6->daddr) & IPV6_ADDR_LINKLOCAL) {
42 lookup_flags |= RT6_LOOKUP_F_IFACE;
43 fl6->flowi6_oif = get_ifindex(dev ? dev : pkt->skb->dev);
44 }
45
46 if (ipv6_addr_type(&fl6->saddr) & IPV6_ADDR_UNICAST)
47 lookup_flags |= RT6_LOOKUP_F_HAS_SADDR;
48
49 if (priv->flags & NFTA_FIB_F_MARK)
50 fl6->flowi6_mark = pkt->skb->mark;
51
52 fl6->flowlabel = (*(__be32 *)iph) & IPV6_FLOWINFO_MASK;
53
54 return lookup_flags;
55 }
56
__nft_fib6_eval_type(const struct nft_fib * priv,const struct nft_pktinfo * pkt,struct ipv6hdr * iph)57 static u32 __nft_fib6_eval_type(const struct nft_fib *priv,
58 const struct nft_pktinfo *pkt,
59 struct ipv6hdr *iph)
60 {
61 const struct net_device *dev = NULL;
62 int route_err, addrtype;
63 struct rt6_info *rt;
64 struct flowi6 fl6 = {
65 .flowi6_iif = LOOPBACK_IFINDEX,
66 .flowi6_proto = pkt->tprot,
67 };
68 u32 ret = 0;
69
70 if (priv->flags & NFTA_FIB_F_IIF)
71 dev = nft_in(pkt);
72 else if (priv->flags & NFTA_FIB_F_OIF)
73 dev = nft_out(pkt);
74
75 nft_fib6_flowi_init(&fl6, priv, pkt, dev, iph);
76
77 if (dev && nf_ipv6_chk_addr(nft_net(pkt), &fl6.daddr, dev, true))
78 ret = RTN_LOCAL;
79
80 route_err = nf_ip6_route(nft_net(pkt), (struct dst_entry **)&rt,
81 flowi6_to_flowi(&fl6), false);
82 if (route_err)
83 goto err;
84
85 if (rt->rt6i_flags & RTF_REJECT) {
86 route_err = rt->dst.error;
87 dst_release(&rt->dst);
88 goto err;
89 }
90
91 if (ipv6_anycast_destination((struct dst_entry *)rt, &fl6.daddr))
92 ret = RTN_ANYCAST;
93 else if (!dev && rt->rt6i_flags & RTF_LOCAL)
94 ret = RTN_LOCAL;
95
96 dst_release(&rt->dst);
97
98 if (ret)
99 return ret;
100
101 addrtype = ipv6_addr_type(&fl6.daddr);
102
103 if (addrtype & IPV6_ADDR_MULTICAST)
104 return RTN_MULTICAST;
105 if (addrtype & IPV6_ADDR_UNICAST)
106 return RTN_UNICAST;
107
108 return RTN_UNSPEC;
109 err:
110 switch (route_err) {
111 case -EINVAL:
112 return RTN_BLACKHOLE;
113 case -EACCES:
114 return RTN_PROHIBIT;
115 case -EAGAIN:
116 return RTN_THROW;
117 default:
118 break;
119 }
120
121 return RTN_UNREACHABLE;
122 }
123
nft_fib6_eval_type(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)124 void nft_fib6_eval_type(const struct nft_expr *expr, struct nft_regs *regs,
125 const struct nft_pktinfo *pkt)
126 {
127 const struct nft_fib *priv = nft_expr_priv(expr);
128 int noff = skb_network_offset(pkt->skb);
129 u32 *dest = ®s->data[priv->dreg];
130 struct ipv6hdr *iph, _iph;
131
132 iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
133 if (!iph) {
134 regs->verdict.code = NFT_BREAK;
135 return;
136 }
137
138 *dest = __nft_fib6_eval_type(priv, pkt, iph);
139 }
140 EXPORT_SYMBOL_GPL(nft_fib6_eval_type);
141
nft_fib_v6_skip_icmpv6(const struct sk_buff * skb,u8 next,const struct ipv6hdr * iph)142 static bool nft_fib_v6_skip_icmpv6(const struct sk_buff *skb, u8 next, const struct ipv6hdr *iph)
143 {
144 if (likely(next != IPPROTO_ICMPV6))
145 return false;
146
147 if (ipv6_addr_type(&iph->saddr) != IPV6_ADDR_ANY)
148 return false;
149
150 return ipv6_addr_type(&iph->daddr) & IPV6_ADDR_LINKLOCAL;
151 }
152
nft_fib6_eval(const struct nft_expr * expr,struct nft_regs * regs,const struct nft_pktinfo * pkt)153 void nft_fib6_eval(const struct nft_expr *expr, struct nft_regs *regs,
154 const struct nft_pktinfo *pkt)
155 {
156 const struct nft_fib *priv = nft_expr_priv(expr);
157 int noff = skb_network_offset(pkt->skb);
158 const struct net_device *oif = NULL;
159 u32 *dest = ®s->data[priv->dreg];
160 struct ipv6hdr *iph, _iph;
161 struct flowi6 fl6 = {
162 .flowi6_iif = LOOPBACK_IFINDEX,
163 .flowi6_proto = pkt->tprot,
164 };
165 struct rt6_info *rt;
166 int lookup_flags;
167
168 if (priv->flags & NFTA_FIB_F_IIF)
169 oif = nft_in(pkt);
170 else if (priv->flags & NFTA_FIB_F_OIF)
171 oif = nft_out(pkt);
172
173 iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
174 if (!iph) {
175 regs->verdict.code = NFT_BREAK;
176 return;
177 }
178
179 lookup_flags = nft_fib6_flowi_init(&fl6, priv, pkt, oif, iph);
180
181 if (nft_hook(pkt) == NF_INET_PRE_ROUTING ||
182 nft_hook(pkt) == NF_INET_INGRESS) {
183 if (nft_fib_is_loopback(pkt->skb, nft_in(pkt)) ||
184 nft_fib_v6_skip_icmpv6(pkt->skb, pkt->tprot, iph)) {
185 nft_fib_store_result(dest, priv, nft_in(pkt));
186 return;
187 }
188 }
189
190 *dest = 0;
191 rt = (void *)ip6_route_lookup(nft_net(pkt), &fl6, pkt->skb,
192 lookup_flags);
193 if (rt->dst.error)
194 goto put_rt_err;
195
196 /* Should not see RTF_LOCAL here */
197 if (rt->rt6i_flags & (RTF_REJECT | RTF_ANYCAST | RTF_LOCAL))
198 goto put_rt_err;
199
200 if (oif && oif != rt->rt6i_idev->dev)
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 .reduce = nft_fib_reduce,
219 };
220
221 static const struct nft_expr_ops nft_fib6_ops = {
222 .type = &nft_fib6_type,
223 .size = NFT_EXPR_SIZE(sizeof(struct nft_fib)),
224 .eval = nft_fib6_eval,
225 .init = nft_fib_init,
226 .dump = nft_fib_dump,
227 .validate = nft_fib_validate,
228 .reduce = nft_fib_reduce,
229 };
230
231 static const struct nft_expr_ops *
nft_fib6_select_ops(const struct nft_ctx * ctx,const struct nlattr * const tb[])232 nft_fib6_select_ops(const struct nft_ctx *ctx,
233 const struct nlattr * const tb[])
234 {
235 enum nft_fib_result result;
236
237 if (!tb[NFTA_FIB_RESULT])
238 return ERR_PTR(-EINVAL);
239
240 result = ntohl(nla_get_be32(tb[NFTA_FIB_RESULT]));
241
242 switch (result) {
243 case NFT_FIB_RESULT_OIF:
244 return &nft_fib6_ops;
245 case NFT_FIB_RESULT_OIFNAME:
246 return &nft_fib6_ops;
247 case NFT_FIB_RESULT_ADDRTYPE:
248 return &nft_fib6_type_ops;
249 default:
250 return ERR_PTR(-EOPNOTSUPP);
251 }
252 }
253
254 static struct nft_expr_type nft_fib6_type __read_mostly = {
255 .name = "fib",
256 .select_ops = nft_fib6_select_ops,
257 .policy = nft_fib_policy,
258 .maxattr = NFTA_FIB_MAX,
259 .family = NFPROTO_IPV6,
260 .owner = THIS_MODULE,
261 };
262
nft_fib6_module_init(void)263 static int __init nft_fib6_module_init(void)
264 {
265 return nft_register_expr(&nft_fib6_type);
266 }
267
nft_fib6_module_exit(void)268 static void __exit nft_fib6_module_exit(void)
269 {
270 nft_unregister_expr(&nft_fib6_type);
271 }
272 module_init(nft_fib6_module_init);
273 module_exit(nft_fib6_module_exit);
274
275 MODULE_LICENSE("GPL");
276 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
277 MODULE_ALIAS_NFT_AF_EXPR(10, "fib");
278 MODULE_DESCRIPTION("nftables fib / ipv6 route lookup support");
279