1 /* 2 * This program is free software; you can redistribute it and/or modify 3 * it under the terms of the GNU General Public License version 2 as 4 * published by the Free Software Foundation. 5 */ 6 7 #include <linux/kernel.h> 8 #include <linux/init.h> 9 #include <linux/module.h> 10 #include <linux/netlink.h> 11 #include <linux/netfilter.h> 12 #include <linux/netfilter/nf_tables.h> 13 #include <linux/netfilter_ipv6.h> 14 #include <net/netfilter/nf_tables_core.h> 15 #include <net/netfilter/nf_tables.h> 16 #include <net/netfilter/nft_fib.h> 17 18 #include <net/ip6_fib.h> 19 #include <net/ip6_route.h> 20 21 static int get_ifindex(const struct net_device *dev) 22 { 23 return dev ? dev->ifindex : 0; 24 } 25 26 static int nft_fib6_flowi_init(struct flowi6 *fl6, const struct nft_fib *priv, 27 const struct nft_pktinfo *pkt, 28 const struct net_device *dev, 29 struct ipv6hdr *iph) 30 { 31 int lookup_flags = 0; 32 33 if (priv->flags & NFTA_FIB_F_DADDR) { 34 fl6->daddr = iph->daddr; 35 fl6->saddr = iph->saddr; 36 } else { 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 const struct nf_ipv6_ops *v6ops; 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 }; 69 u32 ret = 0; 70 71 v6ops = nf_get_ipv6_ops(); 72 if (!v6ops) 73 return RTN_UNREACHABLE; 74 75 if (priv->flags & NFTA_FIB_F_IIF) 76 dev = nft_in(pkt); 77 else if (priv->flags & NFTA_FIB_F_OIF) 78 dev = nft_out(pkt); 79 80 nft_fib6_flowi_init(&fl6, priv, pkt, dev, iph); 81 82 if (dev && v6ops->chk_addr(nft_net(pkt), &fl6.daddr, dev, true)) 83 ret = RTN_LOCAL; 84 85 route_err = v6ops->route(nft_net(pkt), (struct dst_entry **)&rt, 86 flowi6_to_flowi(&fl6), false); 87 if (route_err) 88 goto err; 89 90 if (rt->rt6i_flags & RTF_REJECT) { 91 route_err = rt->dst.error; 92 dst_release(&rt->dst); 93 goto err; 94 } 95 96 if (ipv6_anycast_destination((struct dst_entry *)rt, &fl6.daddr)) 97 ret = RTN_ANYCAST; 98 else if (!dev && rt->rt6i_flags & RTF_LOCAL) 99 ret = RTN_LOCAL; 100 101 dst_release(&rt->dst); 102 103 if (ret) 104 return ret; 105 106 addrtype = ipv6_addr_type(&fl6.daddr); 107 108 if (addrtype & IPV6_ADDR_MULTICAST) 109 return RTN_MULTICAST; 110 if (addrtype & IPV6_ADDR_UNICAST) 111 return RTN_UNICAST; 112 113 return RTN_UNSPEC; 114 err: 115 switch (route_err) { 116 case -EINVAL: 117 return RTN_BLACKHOLE; 118 case -EACCES: 119 return RTN_PROHIBIT; 120 case -EAGAIN: 121 return RTN_THROW; 122 default: 123 break; 124 } 125 126 return RTN_UNREACHABLE; 127 } 128 129 void nft_fib6_eval_type(const struct nft_expr *expr, struct nft_regs *regs, 130 const struct nft_pktinfo *pkt) 131 { 132 const struct nft_fib *priv = nft_expr_priv(expr); 133 int noff = skb_network_offset(pkt->skb); 134 u32 *dest = ®s->data[priv->dreg]; 135 struct ipv6hdr *iph, _iph; 136 137 iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph); 138 if (!iph) { 139 regs->verdict.code = NFT_BREAK; 140 return; 141 } 142 143 *dest = __nft_fib6_eval_type(priv, pkt, iph); 144 } 145 EXPORT_SYMBOL_GPL(nft_fib6_eval_type); 146 147 void nft_fib6_eval(const struct nft_expr *expr, struct nft_regs *regs, 148 const struct nft_pktinfo *pkt) 149 { 150 const struct nft_fib *priv = nft_expr_priv(expr); 151 int noff = skb_network_offset(pkt->skb); 152 const struct net_device *oif = NULL; 153 u32 *dest = ®s->data[priv->dreg]; 154 struct ipv6hdr *iph, _iph; 155 struct flowi6 fl6 = { 156 .flowi6_iif = LOOPBACK_IFINDEX, 157 .flowi6_proto = pkt->tprot, 158 }; 159 struct rt6_info *rt; 160 int lookup_flags; 161 162 if (priv->flags & NFTA_FIB_F_IIF) 163 oif = nft_in(pkt); 164 else if (priv->flags & NFTA_FIB_F_OIF) 165 oif = nft_out(pkt); 166 167 iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph); 168 if (!iph) { 169 regs->verdict.code = NFT_BREAK; 170 return; 171 } 172 173 lookup_flags = nft_fib6_flowi_init(&fl6, priv, pkt, oif, iph); 174 175 if (nft_hook(pkt) == NF_INET_PRE_ROUTING && 176 nft_fib_is_loopback(pkt->skb, nft_in(pkt))) { 177 nft_fib_store_result(dest, priv, pkt, 178 nft_in(pkt)->ifindex); 179 return; 180 } 181 182 *dest = 0; 183 rt = (void *)ip6_route_lookup(nft_net(pkt), &fl6, pkt->skb, 184 lookup_flags); 185 if (rt->dst.error) 186 goto put_rt_err; 187 188 /* Should not see RTF_LOCAL here */ 189 if (rt->rt6i_flags & (RTF_REJECT | RTF_ANYCAST | RTF_LOCAL)) 190 goto put_rt_err; 191 192 if (oif && oif != rt->rt6i_idev->dev) 193 goto put_rt_err; 194 195 switch (priv->result) { 196 case NFT_FIB_RESULT_OIF: 197 *dest = rt->rt6i_idev->dev->ifindex; 198 break; 199 case NFT_FIB_RESULT_OIFNAME: 200 strncpy((char *)dest, rt->rt6i_idev->dev->name, IFNAMSIZ); 201 break; 202 default: 203 WARN_ON_ONCE(1); 204 break; 205 } 206 207 put_rt_err: 208 ip6_rt_put(rt); 209 } 210 EXPORT_SYMBOL_GPL(nft_fib6_eval); 211 212 static struct nft_expr_type nft_fib6_type; 213 214 static const struct nft_expr_ops nft_fib6_type_ops = { 215 .type = &nft_fib6_type, 216 .size = NFT_EXPR_SIZE(sizeof(struct nft_fib)), 217 .eval = nft_fib6_eval_type, 218 .init = nft_fib_init, 219 .dump = nft_fib_dump, 220 .validate = nft_fib_validate, 221 }; 222 223 static const struct nft_expr_ops nft_fib6_ops = { 224 .type = &nft_fib6_type, 225 .size = NFT_EXPR_SIZE(sizeof(struct nft_fib)), 226 .eval = nft_fib6_eval, 227 .init = nft_fib_init, 228 .dump = nft_fib_dump, 229 .validate = nft_fib_validate, 230 }; 231 232 static const struct nft_expr_ops * 233 nft_fib6_select_ops(const struct nft_ctx *ctx, 234 const struct nlattr * const tb[]) 235 { 236 enum nft_fib_result result; 237 238 if (!tb[NFTA_FIB_RESULT]) 239 return ERR_PTR(-EINVAL); 240 241 result = ntohl(nla_get_be32(tb[NFTA_FIB_RESULT])); 242 243 switch (result) { 244 case NFT_FIB_RESULT_OIF: 245 return &nft_fib6_ops; 246 case NFT_FIB_RESULT_OIFNAME: 247 return &nft_fib6_ops; 248 case NFT_FIB_RESULT_ADDRTYPE: 249 return &nft_fib6_type_ops; 250 default: 251 return ERR_PTR(-EOPNOTSUPP); 252 } 253 } 254 255 static struct nft_expr_type nft_fib6_type __read_mostly = { 256 .name = "fib", 257 .select_ops = nft_fib6_select_ops, 258 .policy = nft_fib_policy, 259 .maxattr = NFTA_FIB_MAX, 260 .family = NFPROTO_IPV6, 261 .owner = THIS_MODULE, 262 }; 263 264 static int __init nft_fib6_module_init(void) 265 { 266 return nft_register_expr(&nft_fib6_type); 267 } 268 269 static void __exit nft_fib6_module_exit(void) 270 { 271 nft_unregister_expr(&nft_fib6_type); 272 } 273 module_init(nft_fib6_module_init); 274 module_exit(nft_fib6_module_exit); 275 276 MODULE_LICENSE("GPL"); 277 MODULE_AUTHOR("Florian Westphal <fw@strlen.de>"); 278 MODULE_ALIAS_NFT_AF_EXPR(10, "fib"); 279