1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/kernel.h>
3 #include <linux/module.h>
4 #include <linux/init.h>
5 #include <linux/netlink.h>
6 #include <linux/netfilter.h>
7 #include <linux/workqueue.h>
8 #include <linux/spinlock.h>
9 #include <linux/netfilter/nf_tables.h>
10 #include <net/ip.h> /* for ipv4 options. */
11 #include <net/netfilter/nf_tables.h>
12 #include <net/netfilter/nf_tables_core.h>
13 #include <net/netfilter/nf_conntrack_core.h>
14 #include <linux/netfilter/nf_conntrack_common.h>
15 #include <net/netfilter/nf_flow_table.h>
16 #include <net/netfilter/nf_conntrack_helper.h>
18 struct nft_flow_offload {
19 struct nft_flowtable *flowtable;
22 static int nft_flow_route(const struct nft_pktinfo *pkt,
23 const struct nf_conn *ct,
24 struct nf_flow_route *route,
25 enum ip_conntrack_dir dir)
27 struct dst_entry *this_dst = skb_dst(pkt->skb);
28 struct dst_entry *other_dst = NULL;
31 memset(&fl, 0, sizeof(fl));
32 switch (nft_pf(pkt)) {
34 fl.u.ip4.daddr = ct->tuplehash[dir].tuple.src.u3.ip;
35 fl.u.ip4.flowi4_oif = nft_in(pkt)->ifindex;
38 fl.u.ip6.daddr = ct->tuplehash[dir].tuple.src.u3.in6;
39 fl.u.ip6.flowi6_oif = nft_in(pkt)->ifindex;
43 nf_route(nft_net(pkt), &other_dst, &fl, false, nft_pf(pkt));
47 route->tuple[dir].dst = this_dst;
48 route->tuple[!dir].dst = other_dst;
53 static bool nft_flow_offload_skip(struct sk_buff *skb)
55 struct ip_options *opt = &(IPCB(skb)->opt);
57 if (unlikely(opt->optlen))
59 if (skb_sec_path(skb))
65 static void nft_flow_offload_eval(const struct nft_expr *expr,
66 struct nft_regs *regs,
67 const struct nft_pktinfo *pkt)
69 struct nft_flow_offload *priv = nft_expr_priv(expr);
70 struct nf_flowtable *flowtable = &priv->flowtable->data;
71 const struct nf_conn_help *help;
72 enum ip_conntrack_info ctinfo;
73 struct nf_flow_route route;
74 struct flow_offload *flow;
75 enum ip_conntrack_dir dir;
79 if (nft_flow_offload_skip(pkt->skb))
82 ct = nf_ct_get(pkt->skb, &ctinfo);
86 switch (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum) {
98 if (!nf_ct_is_confirmed(ct))
101 if (test_and_set_bit(IPS_OFFLOAD_BIT, &ct->status))
104 dir = CTINFO2DIR(ctinfo);
105 if (nft_flow_route(pkt, ct, &route, dir) < 0)
108 flow = flow_offload_alloc(ct, &route);
112 ret = flow_offload_add(flowtable, flow);
116 dst_release(route.tuple[!dir].dst);
120 flow_offload_free(flow);
122 dst_release(route.tuple[!dir].dst);
124 clear_bit(IPS_OFFLOAD_BIT, &ct->status);
126 regs->verdict.code = NFT_BREAK;
129 static int nft_flow_offload_validate(const struct nft_ctx *ctx,
130 const struct nft_expr *expr,
131 const struct nft_data **data)
133 unsigned int hook_mask = (1 << NF_INET_FORWARD);
135 return nft_chain_validate_hooks(ctx->chain, hook_mask);
138 static int nft_flow_offload_init(const struct nft_ctx *ctx,
139 const struct nft_expr *expr,
140 const struct nlattr * const tb[])
142 struct nft_flow_offload *priv = nft_expr_priv(expr);
143 u8 genmask = nft_genmask_next(ctx->net);
144 struct nft_flowtable *flowtable;
146 if (!tb[NFTA_FLOW_TABLE_NAME])
149 flowtable = nft_flowtable_lookup(ctx->table, tb[NFTA_FLOW_TABLE_NAME],
151 if (IS_ERR(flowtable))
152 return PTR_ERR(flowtable);
154 priv->flowtable = flowtable;
157 return nf_ct_netns_get(ctx->net, ctx->family);
160 static void nft_flow_offload_destroy(const struct nft_ctx *ctx,
161 const struct nft_expr *expr)
163 struct nft_flow_offload *priv = nft_expr_priv(expr);
165 priv->flowtable->use--;
166 nf_ct_netns_put(ctx->net, ctx->family);
169 static int nft_flow_offload_dump(struct sk_buff *skb, const struct nft_expr *expr)
171 struct nft_flow_offload *priv = nft_expr_priv(expr);
173 if (nla_put_string(skb, NFTA_FLOW_TABLE_NAME, priv->flowtable->name))
174 goto nla_put_failure;
182 static struct nft_expr_type nft_flow_offload_type;
183 static const struct nft_expr_ops nft_flow_offload_ops = {
184 .type = &nft_flow_offload_type,
185 .size = NFT_EXPR_SIZE(sizeof(struct nft_flow_offload)),
186 .eval = nft_flow_offload_eval,
187 .init = nft_flow_offload_init,
188 .destroy = nft_flow_offload_destroy,
189 .validate = nft_flow_offload_validate,
190 .dump = nft_flow_offload_dump,
193 static struct nft_expr_type nft_flow_offload_type __read_mostly = {
194 .name = "flow_offload",
195 .ops = &nft_flow_offload_ops,
196 .maxattr = NFTA_FLOW_MAX,
197 .owner = THIS_MODULE,
200 static int flow_offload_netdev_event(struct notifier_block *this,
201 unsigned long event, void *ptr)
203 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
205 if (event != NETDEV_DOWN)
208 nf_flow_table_cleanup(dev);
213 static struct notifier_block flow_offload_netdev_notifier = {
214 .notifier_call = flow_offload_netdev_event,
217 static int __init nft_flow_offload_module_init(void)
221 err = register_netdevice_notifier(&flow_offload_netdev_notifier);
225 err = nft_register_expr(&nft_flow_offload_type);
232 unregister_netdevice_notifier(&flow_offload_netdev_notifier);
237 static void __exit nft_flow_offload_module_exit(void)
239 nft_unregister_expr(&nft_flow_offload_type);
240 unregister_netdevice_notifier(&flow_offload_netdev_notifier);
243 module_init(nft_flow_offload_module_init);
244 module_exit(nft_flow_offload_module_exit);
246 MODULE_LICENSE("GPL");
247 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
248 MODULE_ALIAS_NFT_EXPR("flow_offload");