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 fl6->flowi6_l3mdev = nft_fib_l3mdev_master_ifindex_rcu(pkt, dev); 54 55 return lookup_flags; 56 } 57 58 static u32 __nft_fib6_eval_type(const struct nft_fib *priv, 59 const struct nft_pktinfo *pkt, 60 struct ipv6hdr *iph) 61 { 62 const struct net_device *dev = NULL; 63 int route_err, addrtype; 64 struct rt6_info *rt; 65 struct flowi6 fl6 = { 66 .flowi6_iif = LOOPBACK_IFINDEX, 67 .flowi6_proto = pkt->tprot, 68 .flowi6_uid = sock_net_uid(nft_net(pkt), NULL), 69 }; 70 u32 ret = 0; 71 72 if (priv->flags & NFTA_FIB_F_IIF) 73 dev = nft_in(pkt); 74 else if (priv->flags & NFTA_FIB_F_OIF) 75 dev = nft_out(pkt); 76 77 nft_fib6_flowi_init(&fl6, priv, pkt, dev, iph); 78 79 if (dev && nf_ipv6_chk_addr(nft_net(pkt), &fl6.daddr, dev, true)) 80 ret = RTN_LOCAL; 81 82 route_err = nf_ip6_route(nft_net(pkt), (struct dst_entry **)&rt, 83 flowi6_to_flowi(&fl6), false); 84 if (route_err) 85 goto err; 86 87 if (rt->rt6i_flags & RTF_REJECT) { 88 route_err = rt->dst.error; 89 dst_release(&rt->dst); 90 goto err; 91 } 92 93 if (ipv6_anycast_destination((struct dst_entry *)rt, &fl6.daddr)) 94 ret = RTN_ANYCAST; 95 else if (!dev && rt->rt6i_flags & RTF_LOCAL) 96 ret = RTN_LOCAL; 97 98 dst_release(&rt->dst); 99 100 if (ret) 101 return ret; 102 103 addrtype = ipv6_addr_type(&fl6.daddr); 104 105 if (addrtype & IPV6_ADDR_MULTICAST) 106 return RTN_MULTICAST; 107 if (addrtype & IPV6_ADDR_UNICAST) 108 return RTN_UNICAST; 109 110 return RTN_UNSPEC; 111 err: 112 switch (route_err) { 113 case -EINVAL: 114 return RTN_BLACKHOLE; 115 case -EACCES: 116 return RTN_PROHIBIT; 117 case -EAGAIN: 118 return RTN_THROW; 119 default: 120 break; 121 } 122 123 return RTN_UNREACHABLE; 124 } 125 126 void nft_fib6_eval_type(const struct nft_expr *expr, struct nft_regs *regs, 127 const struct nft_pktinfo *pkt) 128 { 129 const struct nft_fib *priv = nft_expr_priv(expr); 130 int noff = skb_network_offset(pkt->skb); 131 u32 *dest = ®s->data[priv->dreg]; 132 struct ipv6hdr *iph, _iph; 133 134 iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph); 135 if (!iph) { 136 regs->verdict.code = NFT_BREAK; 137 return; 138 } 139 140 *dest = __nft_fib6_eval_type(priv, pkt, iph); 141 } 142 EXPORT_SYMBOL_GPL(nft_fib6_eval_type); 143 144 static bool nft_fib_v6_skip_icmpv6(const struct sk_buff *skb, u8 next, const struct ipv6hdr *iph) 145 { 146 if (likely(next != IPPROTO_ICMPV6)) 147 return false; 148 149 if (ipv6_addr_type(&iph->saddr) != IPV6_ADDR_ANY) 150 return false; 151 152 return ipv6_addr_type(&iph->daddr) & IPV6_ADDR_LINKLOCAL; 153 } 154 155 void nft_fib6_eval(const struct nft_expr *expr, struct nft_regs *regs, 156 const struct nft_pktinfo *pkt) 157 { 158 const struct nft_fib *priv = nft_expr_priv(expr); 159 int noff = skb_network_offset(pkt->skb); 160 const struct net_device *found = NULL; 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 }; 169 struct rt6_info *rt; 170 int lookup_flags; 171 172 if (nft_fib_can_skip(pkt)) { 173 nft_fib_store_result(dest, priv, nft_in(pkt)); 174 return; 175 } 176 177 if (priv->flags & NFTA_FIB_F_IIF) 178 oif = nft_in(pkt); 179 else if (priv->flags & NFTA_FIB_F_OIF) 180 oif = nft_out(pkt); 181 182 iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph); 183 if (!iph) { 184 regs->verdict.code = NFT_BREAK; 185 return; 186 } 187 188 if (nft_fib_v6_skip_icmpv6(pkt->skb, pkt->tprot, iph)) { 189 nft_fib_store_result(dest, priv, nft_in(pkt)); 190 return; 191 } 192 193 lookup_flags = nft_fib6_flowi_init(&fl6, priv, pkt, oif, iph); 194 195 *dest = 0; 196 rt = (void *)ip6_route_lookup(nft_net(pkt), &fl6, pkt->skb, 197 lookup_flags); 198 if (rt->dst.error) 199 goto put_rt_err; 200 201 /* Should not see RTF_LOCAL here */ 202 if (rt->rt6i_flags & (RTF_REJECT | RTF_ANYCAST | RTF_LOCAL)) 203 goto put_rt_err; 204 205 if (!oif) { 206 found = rt->rt6i_idev->dev; 207 } else { 208 if (oif == rt->rt6i_idev->dev || 209 l3mdev_master_ifindex_rcu(rt->rt6i_idev->dev) == oif->ifindex) 210 found = oif; 211 } 212 213 nft_fib_store_result(dest, priv, found); 214 put_rt_err: 215 ip6_rt_put(rt); 216 } 217 EXPORT_SYMBOL_GPL(nft_fib6_eval); 218 219 static struct nft_expr_type nft_fib6_type; 220 221 static const struct nft_expr_ops nft_fib6_type_ops = { 222 .type = &nft_fib6_type, 223 .size = NFT_EXPR_SIZE(sizeof(struct nft_fib)), 224 .eval = nft_fib6_eval_type, 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_ops = { 232 .type = &nft_fib6_type, 233 .size = NFT_EXPR_SIZE(sizeof(struct nft_fib)), 234 .eval = nft_fib6_eval, 235 .init = nft_fib_init, 236 .dump = nft_fib_dump, 237 .validate = nft_fib_validate, 238 .reduce = nft_fib_reduce, 239 }; 240 241 static const struct nft_expr_ops * 242 nft_fib6_select_ops(const struct nft_ctx *ctx, 243 const struct nlattr * const tb[]) 244 { 245 enum nft_fib_result result; 246 247 if (!tb[NFTA_FIB_RESULT]) 248 return ERR_PTR(-EINVAL); 249 250 result = ntohl(nla_get_be32(tb[NFTA_FIB_RESULT])); 251 252 switch (result) { 253 case NFT_FIB_RESULT_OIF: 254 return &nft_fib6_ops; 255 case NFT_FIB_RESULT_OIFNAME: 256 return &nft_fib6_ops; 257 case NFT_FIB_RESULT_ADDRTYPE: 258 return &nft_fib6_type_ops; 259 default: 260 return ERR_PTR(-EOPNOTSUPP); 261 } 262 } 263 264 static struct nft_expr_type nft_fib6_type __read_mostly = { 265 .name = "fib", 266 .select_ops = nft_fib6_select_ops, 267 .policy = nft_fib_policy, 268 .maxattr = NFTA_FIB_MAX, 269 .family = NFPROTO_IPV6, 270 .owner = THIS_MODULE, 271 }; 272 273 static int __init nft_fib6_module_init(void) 274 { 275 return nft_register_expr(&nft_fib6_type); 276 } 277 278 static void __exit nft_fib6_module_exit(void) 279 { 280 nft_unregister_expr(&nft_fib6_type); 281 } 282 module_init(nft_fib6_module_init); 283 module_exit(nft_fib6_module_exit); 284 285 MODULE_LICENSE("GPL"); 286 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>"); 287 MODULE_ALIAS_NFT_AF_EXPR(10, "fib"); 288 MODULE_DESCRIPTION("nftables fib / ipv6 route lookup support"); 289