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 }; 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 } 123 124 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); 141 142 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 } 152 153 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 * 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 }; 262 263 static int __init nft_fib6_module_init(void) 264 { 265 return nft_register_expr(&nft_fib6_type); 266 } 267 268 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