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- // SPDX-License-Identifier: GPL-2.0-only
- #include <linux/kernel.h>
- #include <linux/init.h>
- #include <linux/module.h>
- #include <linux/netlink.h>
- #include <linux/netfilter.h>
- #include <linux/netfilter/nf_tables.h>
- #include <net/netfilter/nf_tables_core.h>
- #include <net/netfilter/nf_tables.h>
- #include <net/netfilter/nft_fib.h>
- #include <net/ip_fib.h>
- #include <net/route.h>
- /* don't try to find route from mcast/bcast/zeronet */
- static __be32 get_saddr(__be32 addr)
- {
- if (ipv4_is_multicast(addr) || ipv4_is_lbcast(addr) ||
- ipv4_is_zeronet(addr))
- return 0;
- return addr;
- }
- #define DSCP_BITS 0xfc
- void nft_fib4_eval_type(const struct nft_expr *expr, struct nft_regs *regs,
- const struct nft_pktinfo *pkt)
- {
- const struct nft_fib *priv = nft_expr_priv(expr);
- int noff = skb_network_offset(pkt->skb);
- u32 *dst = ®s->data[priv->dreg];
- const struct net_device *dev = NULL;
- struct iphdr *iph, _iph;
- __be32 addr;
- if (priv->flags & NFTA_FIB_F_IIF)
- dev = nft_in(pkt);
- else if (priv->flags & NFTA_FIB_F_OIF)
- dev = nft_out(pkt);
- iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
- if (!iph) {
- regs->verdict.code = NFT_BREAK;
- return;
- }
- if (priv->flags & NFTA_FIB_F_DADDR)
- addr = iph->daddr;
- else
- addr = iph->saddr;
- *dst = inet_dev_addr_type(nft_net(pkt), dev, addr);
- }
- EXPORT_SYMBOL_GPL(nft_fib4_eval_type);
- void nft_fib4_eval(const struct nft_expr *expr, struct nft_regs *regs,
- const struct nft_pktinfo *pkt)
- {
- const struct nft_fib *priv = nft_expr_priv(expr);
- int noff = skb_network_offset(pkt->skb);
- u32 *dest = ®s->data[priv->dreg];
- struct iphdr *iph, _iph;
- struct fib_result res;
- struct flowi4 fl4 = {
- .flowi4_scope = RT_SCOPE_UNIVERSE,
- .flowi4_iif = LOOPBACK_IFINDEX,
- };
- const struct net_device *oif;
- const struct net_device *found;
- /*
- * Do not set flowi4_oif, it restricts results (for example, asking
- * for oif 3 will get RTN_UNICAST result even if the daddr exits
- * on another interface.
- *
- * Search results for the desired outinterface instead.
- */
- if (priv->flags & NFTA_FIB_F_OIF)
- oif = nft_out(pkt);
- else if (priv->flags & NFTA_FIB_F_IIF)
- oif = nft_in(pkt);
- else
- oif = NULL;
- if (nft_hook(pkt) == NF_INET_PRE_ROUTING &&
- nft_fib_is_loopback(pkt->skb, nft_in(pkt))) {
- nft_fib_store_result(dest, priv, nft_in(pkt));
- return;
- }
- iph = skb_header_pointer(pkt->skb, noff, sizeof(_iph), &_iph);
- if (!iph) {
- regs->verdict.code = NFT_BREAK;
- return;
- }
- if (ipv4_is_zeronet(iph->saddr)) {
- if (ipv4_is_lbcast(iph->daddr) ||
- ipv4_is_local_multicast(iph->daddr)) {
- nft_fib_store_result(dest, priv, pkt->skb->dev);
- return;
- }
- }
- if (priv->flags & NFTA_FIB_F_MARK)
- fl4.flowi4_mark = pkt->skb->mark;
- fl4.flowi4_tos = iph->tos & DSCP_BITS;
- if (priv->flags & NFTA_FIB_F_DADDR) {
- fl4.daddr = iph->daddr;
- fl4.saddr = get_saddr(iph->saddr);
- } else {
- fl4.daddr = iph->saddr;
- fl4.saddr = get_saddr(iph->daddr);
- }
- *dest = 0;
- if (fib_lookup(nft_net(pkt), &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE))
- return;
- switch (res.type) {
- case RTN_UNICAST:
- break;
- case RTN_LOCAL: /* Should not see RTN_LOCAL here */
- return;
- default:
- break;
- }
- if (!oif) {
- found = FIB_RES_DEV(res);
- } else {
- if (!fib_info_nh_uses_dev(res.fi, oif))
- return;
- found = oif;
- }
- nft_fib_store_result(dest, priv, found);
- }
- EXPORT_SYMBOL_GPL(nft_fib4_eval);
- static struct nft_expr_type nft_fib4_type;
- static const struct nft_expr_ops nft_fib4_type_ops = {
- .type = &nft_fib4_type,
- .size = NFT_EXPR_SIZE(sizeof(struct nft_fib)),
- .eval = nft_fib4_eval_type,
- .init = nft_fib_init,
- .dump = nft_fib_dump,
- .validate = nft_fib_validate,
- };
- static const struct nft_expr_ops nft_fib4_ops = {
- .type = &nft_fib4_type,
- .size = NFT_EXPR_SIZE(sizeof(struct nft_fib)),
- .eval = nft_fib4_eval,
- .init = nft_fib_init,
- .dump = nft_fib_dump,
- .validate = nft_fib_validate,
- };
- static const struct nft_expr_ops *
- nft_fib4_select_ops(const struct nft_ctx *ctx,
- const struct nlattr * const tb[])
- {
- enum nft_fib_result result;
- if (!tb[NFTA_FIB_RESULT])
- return ERR_PTR(-EINVAL);
- result = ntohl(nla_get_be32(tb[NFTA_FIB_RESULT]));
- switch (result) {
- case NFT_FIB_RESULT_OIF:
- return &nft_fib4_ops;
- case NFT_FIB_RESULT_OIFNAME:
- return &nft_fib4_ops;
- case NFT_FIB_RESULT_ADDRTYPE:
- return &nft_fib4_type_ops;
- default:
- return ERR_PTR(-EOPNOTSUPP);
- }
- }
- static struct nft_expr_type nft_fib4_type __read_mostly = {
- .name = "fib",
- .select_ops = nft_fib4_select_ops,
- .policy = nft_fib_policy,
- .maxattr = NFTA_FIB_MAX,
- .family = NFPROTO_IPV4,
- .owner = THIS_MODULE,
- };
- static int __init nft_fib4_module_init(void)
- {
- return nft_register_expr(&nft_fib4_type);
- }
- static void __exit nft_fib4_module_exit(void)
- {
- nft_unregister_expr(&nft_fib4_type);
- }
- module_init(nft_fib4_module_init);
- module_exit(nft_fib4_module_exit);
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
- MODULE_ALIAS_NFT_AF_EXPR(2, "fib");
- MODULE_DESCRIPTION("nftables fib / ip route lookup support");
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