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 17 static int get_ifindex(const struct net_device *dev) 18 { 19 return dev ? dev->ifindex : 0; 20 } 21 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 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 .flowi6_uid = sock_net_uid(nft_net(pkt), NULL), 68 }; 69 u32 ret = 0; 70 71 if (priv->flags & NFTA_FIB_F_IIF) 72 dev = nft_in(pkt); 73 else if (priv->flags & NFTA_FIB_F_OIF) 74 dev = nft_out(pkt); 75 76 fl6.flowi6_l3mdev = l3mdev_master_ifindex_rcu(dev); 77 78 nft_fib6_flowi_init(&fl6, priv, pkt, dev, iph); 79 80 if (dev && nf_ipv6_chk_addr(nft_net(pkt), &fl6.daddr, dev, true)) 81 ret = RTN_LOCAL; 82 83 route_err = nf_ip6_route(nft_net(pkt), (struct dst_entry **)&rt, 84 flowi6_to_flowi(&fl6), false); 85 if (route_err) 86 goto err; 87 88 if (rt->rt6i_flags & RTF_REJECT) { 89 route_err = rt->dst.error; 90 dst_release(&rt->dst); 91 goto err; 92 } 93 94 if (ipv6_anycast_destination((struct dst_entry *)rt, &fl6.daddr)) 95 ret = RTN_ANYCAST; 96 else if (!dev && rt->rt6i_flags & RTF_LOCAL) 97 ret = RTN_LOCAL; 98 99 dst_release(&rt->dst); 100 101 if (ret) 102 return ret; 103 104 addrtype = ipv6_addr_type(&fl6.daddr); 105 106 if (addrtype & IPV6_ADDR_MULTICAST) 107 return RTN_MULTICAST; 108 if (addrtype & IPV6_ADDR_UNICAST) 109 return RTN_UNICAST; 110 111 return RTN_UNSPEC; 112 err: 113 switch (route_err) { 114 case -EINVAL: 115 return RTN_BLACKHOLE; 116 case -EACCES: 117 return RTN_PROHIBIT; 118 case -EAGAIN: 119 return RTN_THROW; 120 default: 121 break; 122 } 123 124 return RTN_UNREACHABLE; 125 } 126 127 void nft_fib6_eval_type(const struct nft_expr *expr, struct nft_regs *regs, 128 const struct nft_pktinfo *pkt) 129 { 130 const struct nft_fib *priv = nft_expr_priv(expr); 131 int noff = skb_network_offset(pkt->skb); 132 u32 *dest = ®s->data[priv->dreg]; 133 struct ipv6hdr *iph, _iph; 134 135 iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph); 136 if (!iph) { 137 regs->verdict.code = NFT_BREAK; 138 return; 139 } 140 141 *dest = __nft_fib6_eval_type(priv, pkt, iph); 142 } 143 EXPORT_SYMBOL_GPL(nft_fib6_eval_type); 144 145 static bool nft_fib_v6_skip_icmpv6(const struct sk_buff *skb, u8 next, const struct ipv6hdr *iph) 146 { 147 if (likely(next != IPPROTO_ICMPV6)) 148 return false; 149 150 if (ipv6_addr_type(&iph->saddr) != IPV6_ADDR_ANY) 151 return false; 152 153 return ipv6_addr_type(&iph->daddr) & IPV6_ADDR_LINKLOCAL; 154 } 155 156 void nft_fib6_eval(const struct nft_expr *expr, struct nft_regs *regs, 157 const struct nft_pktinfo *pkt) 158 { 159 const struct nft_fib *priv = nft_expr_priv(expr); 160 int noff = skb_network_offset(pkt->skb); 161 const struct net_device *oif = NULL; 162 u32 *dest = ®s->data[priv->dreg]; 163 struct ipv6hdr *iph, _iph; 164 struct flowi6 fl6 = { 165 .flowi6_iif = LOOPBACK_IFINDEX, 166 .flowi6_proto = pkt->tprot, 167 .flowi6_uid = sock_net_uid(nft_net(pkt), NULL), 168 .flowi6_l3mdev = l3mdev_master_ifindex_rcu(nft_in(pkt)), 169 }; 170 struct rt6_info *rt; 171 int lookup_flags; 172 173 if (nft_fib_can_skip(pkt)) { 174 nft_fib_store_result(dest, priv, nft_in(pkt)); 175 return; 176 } 177 178 if (priv->flags & NFTA_FIB_F_IIF) 179 oif = nft_in(pkt); 180 else if (priv->flags & NFTA_FIB_F_OIF) 181 oif = nft_out(pkt); 182 183 iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph); 184 if (!iph) { 185 regs->verdict.code = NFT_BREAK; 186 return; 187 } 188 189 if (nft_fib_v6_skip_icmpv6(pkt->skb, pkt->tprot, iph)) { 190 nft_fib_store_result(dest, priv, nft_in(pkt)); 191 return; 192 } 193 194 lookup_flags = nft_fib6_flowi_init(&fl6, priv, pkt, oif, iph); 195 196 *dest = 0; 197 rt = (void *)ip6_route_lookup(nft_net(pkt), &fl6, pkt->skb, 198 lookup_flags); 199 if (rt->dst.error) 200 goto put_rt_err; 201 202 /* Should not see RTF_LOCAL here */ 203 if (rt->rt6i_flags & (RTF_REJECT | RTF_ANYCAST | RTF_LOCAL)) 204 goto put_rt_err; 205 206 if (oif && oif != rt->rt6i_idev->dev && 207 l3mdev_master_ifindex_rcu(rt->rt6i_idev->dev) != oif->ifindex) 208 goto put_rt_err; 209 210 nft_fib_store_result(dest, priv, rt->rt6i_idev->dev); 211 put_rt_err: 212 ip6_rt_put(rt); 213 } 214 EXPORT_SYMBOL_GPL(nft_fib6_eval); 215 216 static struct nft_expr_type nft_fib6_type; 217 218 static const struct nft_expr_ops nft_fib6_type_ops = { 219 .type = &nft_fib6_type, 220 .size = NFT_EXPR_SIZE(sizeof(struct nft_fib)), 221 .eval = nft_fib6_eval_type, 222 .init = nft_fib_init, 223 .dump = nft_fib_dump, 224 .validate = nft_fib_validate, 225 .reduce = nft_fib_reduce, 226 }; 227 228 static const struct nft_expr_ops nft_fib6_ops = { 229 .type = &nft_fib6_type, 230 .size = NFT_EXPR_SIZE(sizeof(struct nft_fib)), 231 .eval = nft_fib6_eval, 232 .init = nft_fib_init, 233 .dump = nft_fib_dump, 234 .validate = nft_fib_validate, 235 .reduce = nft_fib_reduce, 236 }; 237 238 static const struct nft_expr_ops * 239 nft_fib6_select_ops(const struct nft_ctx *ctx, 240 const struct nlattr * const tb[]) 241 { 242 enum nft_fib_result result; 243 244 if (!tb[NFTA_FIB_RESULT]) 245 return ERR_PTR(-EINVAL); 246 247 result = ntohl(nla_get_be32(tb[NFTA_FIB_RESULT])); 248 249 switch (result) { 250 case NFT_FIB_RESULT_OIF: 251 return &nft_fib6_ops; 252 case NFT_FIB_RESULT_OIFNAME: 253 return &nft_fib6_ops; 254 case NFT_FIB_RESULT_ADDRTYPE: 255 return &nft_fib6_type_ops; 256 default: 257 return ERR_PTR(-EOPNOTSUPP); 258 } 259 } 260 261 static struct nft_expr_type nft_fib6_type __read_mostly = { 262 .name = "fib", 263 .select_ops = nft_fib6_select_ops, 264 .policy = nft_fib_policy, 265 .maxattr = NFTA_FIB_MAX, 266 .family = NFPROTO_IPV6, 267 .owner = THIS_MODULE, 268 }; 269 270 static int __init nft_fib6_module_init(void) 271 { 272 return nft_register_expr(&nft_fib6_type); 273 } 274 275 static void __exit nft_fib6_module_exit(void) 276 { 277 nft_unregister_expr(&nft_fib6_type); 278 } 279 module_init(nft_fib6_module_init); 280 module_exit(nft_fib6_module_exit); 281 282 MODULE_LICENSE("GPL"); 283 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>"); 284 MODULE_ALIAS_NFT_AF_EXPR(10, "fib"); 285 MODULE_DESCRIPTION("nftables fib / ipv6 route lookup support"); 286