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_conntrack_common.h>
10#include <linux/netfilter/nf_tables.h>
11#include <net/ip.h> /* for ipv4 options. */
12#include <net/netfilter/nf_tables.h>
13#include <net/netfilter/nf_tables_core.h>
14#include <net/netfilter/nf_conntrack_core.h>
15#include <net/netfilter/nf_conntrack_extend.h>
16#include <net/netfilter/nf_flow_table.h>
17
18struct nft_flow_offload {
19 struct nft_flowtable *flowtable;
20};
21
22static enum flow_offload_xmit_type nft_xmit_type(struct dst_entry *dst)
23{
24 if (dst_xfrm(dst))
25 return FLOW_OFFLOAD_XMIT_XFRM;
26
27 return FLOW_OFFLOAD_XMIT_NEIGH;
28}
29
30static void nft_default_forward_path(struct nf_flow_route *route,
31 struct dst_entry *dst_cache,
32 enum ip_conntrack_dir dir)
33{
34 route->tuple[!dir].in.ifindex = dst_cache->dev->ifindex;
35 route->tuple[dir].dst = dst_cache;
36 route->tuple[dir].xmit_type = nft_xmit_type(dst: dst_cache);
37}
38
39static bool nft_is_valid_ether_device(const struct net_device *dev)
40{
41 if (!dev || (dev->flags & IFF_LOOPBACK) || dev->type != ARPHRD_ETHER ||
42 dev->addr_len != ETH_ALEN || !is_valid_ether_addr(addr: dev->dev_addr))
43 return false;
44
45 return true;
46}
47
48static int nft_dev_fill_forward_path(const struct nf_flow_route *route,
49 const struct dst_entry *dst_cache,
50 const struct nf_conn *ct,
51 enum ip_conntrack_dir dir, u8 *ha,
52 struct net_device_path_stack *stack)
53{
54 const void *daddr = &ct->tuplehash[!dir].tuple.src.u3;
55 struct net_device *dev = dst_cache->dev;
56 struct neighbour *n;
57 u8 nud_state;
58
59 if (!nft_is_valid_ether_device(dev))
60 goto out;
61
62 n = dst_neigh_lookup(dst: dst_cache, daddr);
63 if (!n)
64 return -1;
65
66 read_lock_bh(&n->lock);
67 nud_state = n->nud_state;
68 ether_addr_copy(dst: ha, src: n->ha);
69 read_unlock_bh(&n->lock);
70 neigh_release(neigh: n);
71
72 if (!(nud_state & NUD_VALID))
73 return -1;
74
75out:
76 return dev_fill_forward_path(dev, daddr: ha, stack);
77}
78
79struct nft_forward_info {
80 const struct net_device *indev;
81 const struct net_device *outdev;
82 const struct net_device *hw_outdev;
83 struct id {
84 __u16 id;
85 __be16 proto;
86 } encap[NF_FLOW_TABLE_ENCAP_MAX];
87 u8 num_encaps;
88 u8 ingress_vlans;
89 u8 h_source[ETH_ALEN];
90 u8 h_dest[ETH_ALEN];
91 enum flow_offload_xmit_type xmit_type;
92};
93
94static void nft_dev_path_info(const struct net_device_path_stack *stack,
95 struct nft_forward_info *info,
96 unsigned char *ha, struct nf_flowtable *flowtable)
97{
98 const struct net_device_path *path;
99 int i;
100
101 memcpy(info->h_dest, ha, ETH_ALEN);
102
103 for (i = 0; i < stack->num_paths; i++) {
104 path = &stack->path[i];
105 switch (path->type) {
106 case DEV_PATH_ETHERNET:
107 case DEV_PATH_DSA:
108 case DEV_PATH_VLAN:
109 case DEV_PATH_PPPOE:
110 info->indev = path->dev;
111 if (is_zero_ether_addr(addr: info->h_source))
112 memcpy(info->h_source, path->dev->dev_addr, ETH_ALEN);
113
114 if (path->type == DEV_PATH_ETHERNET)
115 break;
116 if (path->type == DEV_PATH_DSA) {
117 i = stack->num_paths;
118 break;
119 }
120
121 /* DEV_PATH_VLAN and DEV_PATH_PPPOE */
122 if (info->num_encaps >= NF_FLOW_TABLE_ENCAP_MAX) {
123 info->indev = NULL;
124 break;
125 }
126 if (!info->outdev)
127 info->outdev = path->dev;
128 info->encap[info->num_encaps].id = path->encap.id;
129 info->encap[info->num_encaps].proto = path->encap.proto;
130 info->num_encaps++;
131 if (path->type == DEV_PATH_PPPOE)
132 memcpy(info->h_dest, path->encap.h_dest, ETH_ALEN);
133 break;
134 case DEV_PATH_BRIDGE:
135 if (is_zero_ether_addr(addr: info->h_source))
136 memcpy(info->h_source, path->dev->dev_addr, ETH_ALEN);
137
138 switch (path->bridge.vlan_mode) {
139 case DEV_PATH_BR_VLAN_UNTAG_HW:
140 info->ingress_vlans |= BIT(info->num_encaps - 1);
141 break;
142 case DEV_PATH_BR_VLAN_TAG:
143 info->encap[info->num_encaps].id = path->bridge.vlan_id;
144 info->encap[info->num_encaps].proto = path->bridge.vlan_proto;
145 info->num_encaps++;
146 break;
147 case DEV_PATH_BR_VLAN_UNTAG:
148 info->num_encaps--;
149 break;
150 case DEV_PATH_BR_VLAN_KEEP:
151 break;
152 }
153 info->xmit_type = FLOW_OFFLOAD_XMIT_DIRECT;
154 break;
155 default:
156 info->indev = NULL;
157 break;
158 }
159 }
160 if (!info->outdev)
161 info->outdev = info->indev;
162
163 info->hw_outdev = info->indev;
164
165 if (nf_flowtable_hw_offload(flowtable) &&
166 nft_is_valid_ether_device(dev: info->indev))
167 info->xmit_type = FLOW_OFFLOAD_XMIT_DIRECT;
168}
169
170static bool nft_flowtable_find_dev(const struct net_device *dev,
171 struct nft_flowtable *ft)
172{
173 struct nft_hook *hook;
174 bool found = false;
175
176 list_for_each_entry_rcu(hook, &ft->hook_list, list) {
177 if (hook->ops.dev != dev)
178 continue;
179
180 found = true;
181 break;
182 }
183
184 return found;
185}
186
187static void nft_dev_forward_path(struct nf_flow_route *route,
188 const struct nf_conn *ct,
189 enum ip_conntrack_dir dir,
190 struct nft_flowtable *ft)
191{
192 const struct dst_entry *dst = route->tuple[dir].dst;
193 struct net_device_path_stack stack;
194 struct nft_forward_info info = {};
195 unsigned char ha[ETH_ALEN];
196 int i;
197
198 if (nft_dev_fill_forward_path(route, dst_cache: dst, ct, dir, ha, stack: &stack) >= 0)
199 nft_dev_path_info(stack: &stack, info: &info, ha, flowtable: &ft->data);
200
201 if (!info.indev || !nft_flowtable_find_dev(dev: info.indev, ft))
202 return;
203
204 route->tuple[!dir].in.ifindex = info.indev->ifindex;
205 for (i = 0; i < info.num_encaps; i++) {
206 route->tuple[!dir].in.encap[i].id = info.encap[i].id;
207 route->tuple[!dir].in.encap[i].proto = info.encap[i].proto;
208 }
209 route->tuple[!dir].in.num_encaps = info.num_encaps;
210 route->tuple[!dir].in.ingress_vlans = info.ingress_vlans;
211
212 if (info.xmit_type == FLOW_OFFLOAD_XMIT_DIRECT) {
213 memcpy(route->tuple[dir].out.h_source, info.h_source, ETH_ALEN);
214 memcpy(route->tuple[dir].out.h_dest, info.h_dest, ETH_ALEN);
215 route->tuple[dir].out.ifindex = info.outdev->ifindex;
216 route->tuple[dir].out.hw_ifindex = info.hw_outdev->ifindex;
217 route->tuple[dir].xmit_type = info.xmit_type;
218 }
219}
220
221static int nft_flow_route(const struct nft_pktinfo *pkt,
222 const struct nf_conn *ct,
223 struct nf_flow_route *route,
224 enum ip_conntrack_dir dir,
225 struct nft_flowtable *ft)
226{
227 struct dst_entry *this_dst = skb_dst(skb: pkt->skb);
228 struct dst_entry *other_dst = NULL;
229 struct flowi fl;
230
231 memset(&fl, 0, sizeof(fl));
232 switch (nft_pf(pkt)) {
233 case NFPROTO_IPV4:
234 fl.u.ip4.daddr = ct->tuplehash[dir].tuple.src.u3.ip;
235 fl.u.ip4.saddr = ct->tuplehash[!dir].tuple.src.u3.ip;
236 fl.u.ip4.flowi4_oif = nft_in(pkt)->ifindex;
237 fl.u.ip4.flowi4_iif = this_dst->dev->ifindex;
238 fl.u.ip4.flowi4_tos = RT_TOS(ip_hdr(pkt->skb)->tos);
239 fl.u.ip4.flowi4_mark = pkt->skb->mark;
240 fl.u.ip4.flowi4_flags = FLOWI_FLAG_ANYSRC;
241 break;
242 case NFPROTO_IPV6:
243 fl.u.ip6.daddr = ct->tuplehash[dir].tuple.src.u3.in6;
244 fl.u.ip6.saddr = ct->tuplehash[!dir].tuple.src.u3.in6;
245 fl.u.ip6.flowi6_oif = nft_in(pkt)->ifindex;
246 fl.u.ip6.flowi6_iif = this_dst->dev->ifindex;
247 fl.u.ip6.flowlabel = ip6_flowinfo(hdr: ipv6_hdr(skb: pkt->skb));
248 fl.u.ip6.flowi6_mark = pkt->skb->mark;
249 fl.u.ip6.flowi6_flags = FLOWI_FLAG_ANYSRC;
250 break;
251 }
252
253 if (!dst_hold_safe(dst: this_dst))
254 return -ENOENT;
255
256 nf_route(net: nft_net(pkt), dst: &other_dst, fl: &fl, strict: false, family: nft_pf(pkt));
257 if (!other_dst) {
258 dst_release(dst: this_dst);
259 return -ENOENT;
260 }
261
262 nft_default_forward_path(route, dst_cache: this_dst, dir);
263 nft_default_forward_path(route, dst_cache: other_dst, dir: !dir);
264
265 if (route->tuple[dir].xmit_type == FLOW_OFFLOAD_XMIT_NEIGH &&
266 route->tuple[!dir].xmit_type == FLOW_OFFLOAD_XMIT_NEIGH) {
267 nft_dev_forward_path(route, ct, dir, ft);
268 nft_dev_forward_path(route, ct, dir: !dir, ft);
269 }
270
271 return 0;
272}
273
274static bool nft_flow_offload_skip(struct sk_buff *skb, int family)
275{
276 if (skb_sec_path(skb))
277 return true;
278
279 if (family == NFPROTO_IPV4) {
280 const struct ip_options *opt;
281
282 opt = &(IPCB(skb)->opt);
283
284 if (unlikely(opt->optlen))
285 return true;
286 }
287
288 return false;
289}
290
291static void nft_flow_offload_eval(const struct nft_expr *expr,
292 struct nft_regs *regs,
293 const struct nft_pktinfo *pkt)
294{
295 struct nft_flow_offload *priv = nft_expr_priv(expr);
296 struct nf_flowtable *flowtable = &priv->flowtable->data;
297 struct tcphdr _tcph, *tcph = NULL;
298 struct nf_flow_route route = {};
299 enum ip_conntrack_info ctinfo;
300 struct flow_offload *flow;
301 enum ip_conntrack_dir dir;
302 struct nf_conn *ct;
303 int ret;
304
305 if (nft_flow_offload_skip(skb: pkt->skb, family: nft_pf(pkt)))
306 goto out;
307
308 ct = nf_ct_get(skb: pkt->skb, ctinfo: &ctinfo);
309 if (!ct)
310 goto out;
311
312 switch (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum) {
313 case IPPROTO_TCP:
314 tcph = skb_header_pointer(skb: pkt->skb, offset: nft_thoff(pkt),
315 len: sizeof(_tcph), buffer: &_tcph);
316 if (unlikely(!tcph || tcph->fin || tcph->rst ||
317 !nf_conntrack_tcp_established(ct)))
318 goto out;
319 break;
320 case IPPROTO_UDP:
321 break;
322#ifdef CONFIG_NF_CT_PROTO_GRE
323 case IPPROTO_GRE: {
324 struct nf_conntrack_tuple *tuple;
325
326 if (ct->status & IPS_NAT_MASK)
327 goto out;
328 tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
329 /* No support for GRE v1 */
330 if (tuple->src.u.gre.key || tuple->dst.u.gre.key)
331 goto out;
332 break;
333 }
334#endif
335 default:
336 goto out;
337 }
338
339 if (nf_ct_ext_exist(ct, id: NF_CT_EXT_HELPER) ||
340 ct->status & (IPS_SEQ_ADJUST | IPS_NAT_CLASH))
341 goto out;
342
343 if (!nf_ct_is_confirmed(ct))
344 goto out;
345
346 if (test_and_set_bit(nr: IPS_OFFLOAD_BIT, addr: &ct->status))
347 goto out;
348
349 dir = CTINFO2DIR(ctinfo);
350 if (nft_flow_route(pkt, ct, route: &route, dir, ft: priv->flowtable) < 0)
351 goto err_flow_route;
352
353 flow = flow_offload_alloc(ct);
354 if (!flow)
355 goto err_flow_alloc;
356
357 flow_offload_route_init(flow, route: &route);
358
359 if (tcph) {
360 ct->proto.tcp.seen[0].flags |= IP_CT_TCP_FLAG_BE_LIBERAL;
361 ct->proto.tcp.seen[1].flags |= IP_CT_TCP_FLAG_BE_LIBERAL;
362 }
363
364 __set_bit(NF_FLOW_HW_BIDIRECTIONAL, &flow->flags);
365 ret = flow_offload_add(flow_table: flowtable, flow);
366 if (ret < 0)
367 goto err_flow_add;
368
369 return;
370
371err_flow_add:
372 flow_offload_free(flow);
373err_flow_alloc:
374 dst_release(dst: route.tuple[dir].dst);
375 dst_release(dst: route.tuple[!dir].dst);
376err_flow_route:
377 clear_bit(nr: IPS_OFFLOAD_BIT, addr: &ct->status);
378out:
379 regs->verdict.code = NFT_BREAK;
380}
381
382static int nft_flow_offload_validate(const struct nft_ctx *ctx,
383 const struct nft_expr *expr,
384 const struct nft_data **data)
385{
386 unsigned int hook_mask = (1 << NF_INET_FORWARD);
387
388 if (ctx->family != NFPROTO_IPV4 &&
389 ctx->family != NFPROTO_IPV6 &&
390 ctx->family != NFPROTO_INET)
391 return -EOPNOTSUPP;
392
393 return nft_chain_validate_hooks(chain: ctx->chain, hook_flags: hook_mask);
394}
395
396static const struct nla_policy nft_flow_offload_policy[NFTA_FLOW_MAX + 1] = {
397 [NFTA_FLOW_TABLE_NAME] = { .type = NLA_STRING,
398 .len = NFT_NAME_MAXLEN - 1 },
399};
400
401static int nft_flow_offload_init(const struct nft_ctx *ctx,
402 const struct nft_expr *expr,
403 const struct nlattr * const tb[])
404{
405 struct nft_flow_offload *priv = nft_expr_priv(expr);
406 u8 genmask = nft_genmask_next(net: ctx->net);
407 struct nft_flowtable *flowtable;
408
409 if (!tb[NFTA_FLOW_TABLE_NAME])
410 return -EINVAL;
411
412 flowtable = nft_flowtable_lookup(table: ctx->table, nla: tb[NFTA_FLOW_TABLE_NAME],
413 genmask);
414 if (IS_ERR(ptr: flowtable))
415 return PTR_ERR(ptr: flowtable);
416
417 if (!nft_use_inc(use: &flowtable->use))
418 return -EMFILE;
419
420 priv->flowtable = flowtable;
421
422 return nf_ct_netns_get(net: ctx->net, nfproto: ctx->family);
423}
424
425static void nft_flow_offload_deactivate(const struct nft_ctx *ctx,
426 const struct nft_expr *expr,
427 enum nft_trans_phase phase)
428{
429 struct nft_flow_offload *priv = nft_expr_priv(expr);
430
431 nf_tables_deactivate_flowtable(ctx, flowtable: priv->flowtable, phase);
432}
433
434static void nft_flow_offload_activate(const struct nft_ctx *ctx,
435 const struct nft_expr *expr)
436{
437 struct nft_flow_offload *priv = nft_expr_priv(expr);
438
439 nft_use_inc_restore(use: &priv->flowtable->use);
440}
441
442static void nft_flow_offload_destroy(const struct nft_ctx *ctx,
443 const struct nft_expr *expr)
444{
445 nf_ct_netns_put(net: ctx->net, nfproto: ctx->family);
446}
447
448static int nft_flow_offload_dump(struct sk_buff *skb,
449 const struct nft_expr *expr, bool reset)
450{
451 struct nft_flow_offload *priv = nft_expr_priv(expr);
452
453 if (nla_put_string(skb, attrtype: NFTA_FLOW_TABLE_NAME, str: priv->flowtable->name))
454 goto nla_put_failure;
455
456 return 0;
457
458nla_put_failure:
459 return -1;
460}
461
462static struct nft_expr_type nft_flow_offload_type;
463static const struct nft_expr_ops nft_flow_offload_ops = {
464 .type = &nft_flow_offload_type,
465 .size = NFT_EXPR_SIZE(sizeof(struct nft_flow_offload)),
466 .eval = nft_flow_offload_eval,
467 .init = nft_flow_offload_init,
468 .activate = nft_flow_offload_activate,
469 .deactivate = nft_flow_offload_deactivate,
470 .destroy = nft_flow_offload_destroy,
471 .validate = nft_flow_offload_validate,
472 .dump = nft_flow_offload_dump,
473 .reduce = NFT_REDUCE_READONLY,
474};
475
476static struct nft_expr_type nft_flow_offload_type __read_mostly = {
477 .name = "flow_offload",
478 .ops = &nft_flow_offload_ops,
479 .policy = nft_flow_offload_policy,
480 .maxattr = NFTA_FLOW_MAX,
481 .owner = THIS_MODULE,
482};
483
484static int flow_offload_netdev_event(struct notifier_block *this,
485 unsigned long event, void *ptr)
486{
487 struct net_device *dev = netdev_notifier_info_to_dev(info: ptr);
488
489 if (event != NETDEV_DOWN)
490 return NOTIFY_DONE;
491
492 nf_flow_table_cleanup(dev);
493
494 return NOTIFY_DONE;
495}
496
497static struct notifier_block flow_offload_netdev_notifier = {
498 .notifier_call = flow_offload_netdev_event,
499};
500
501static int __init nft_flow_offload_module_init(void)
502{
503 int err;
504
505 err = register_netdevice_notifier(nb: &flow_offload_netdev_notifier);
506 if (err)
507 goto err;
508
509 err = nft_register_expr(&nft_flow_offload_type);
510 if (err < 0)
511 goto register_expr;
512
513 return 0;
514
515register_expr:
516 unregister_netdevice_notifier(nb: &flow_offload_netdev_notifier);
517err:
518 return err;
519}
520
521static void __exit nft_flow_offload_module_exit(void)
522{
523 nft_unregister_expr(&nft_flow_offload_type);
524 unregister_netdevice_notifier(nb: &flow_offload_netdev_notifier);
525}
526
527module_init(nft_flow_offload_module_init);
528module_exit(nft_flow_offload_module_exit);
529
530MODULE_LICENSE("GPL");
531MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
532MODULE_ALIAS_NFT_EXPR("flow_offload");
533MODULE_DESCRIPTION("nftables hardware flow offload module");
534

source code of linux/net/netfilter/nft_flow_offload.c