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