1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2023 Isovalent */
3
4#include <linux/netdevice.h>
5#include <linux/ethtool.h>
6#include <linux/etherdevice.h>
7#include <linux/filter.h>
8#include <linux/netfilter_netdev.h>
9#include <linux/bpf_mprog.h>
10#include <linux/indirect_call_wrapper.h>
11
12#include <net/netkit.h>
13#include <net/dst.h>
14#include <net/tcx.h>
15
16#define DRV_NAME "netkit"
17
18struct netkit {
19 /* Needed in fast-path */
20 struct net_device __rcu *peer;
21 struct bpf_mprog_entry __rcu *active;
22 enum netkit_action policy;
23 enum netkit_scrub scrub;
24 struct bpf_mprog_bundle bundle;
25
26 /* Needed in slow-path */
27 enum netkit_mode mode;
28 bool primary;
29 u32 headroom;
30};
31
32struct netkit_link {
33 struct bpf_link link;
34 struct net_device *dev;
35 u32 location;
36};
37
38static __always_inline int
39netkit_run(const struct bpf_mprog_entry *entry, struct sk_buff *skb,
40 enum netkit_action ret)
41{
42 const struct bpf_mprog_fp *fp;
43 const struct bpf_prog *prog;
44
45 bpf_mprog_foreach_prog(entry, fp, prog) {
46 bpf_compute_data_pointers(skb);
47 ret = bpf_prog_run(prog, ctx: skb);
48 if (ret != NETKIT_NEXT)
49 break;
50 }
51 return ret;
52}
53
54static void netkit_xnet(struct sk_buff *skb)
55{
56 skb->priority = 0;
57 skb->mark = 0;
58}
59
60static void netkit_prep_forward(struct sk_buff *skb,
61 bool xnet, bool xnet_scrub)
62{
63 skb_scrub_packet(skb, xnet: false);
64 nf_skip_egress(skb, skip: true);
65 skb_reset_mac_header(skb);
66 if (!xnet)
67 return;
68 skb_clear_tstamp(skb);
69 if (xnet_scrub)
70 netkit_xnet(skb);
71}
72
73static struct netkit *netkit_priv(const struct net_device *dev)
74{
75 return netdev_priv(dev);
76}
77
78static netdev_tx_t netkit_xmit(struct sk_buff *skb, struct net_device *dev)
79{
80 struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx;
81 struct netkit *nk = netkit_priv(dev);
82 enum netkit_action ret = READ_ONCE(nk->policy);
83 netdev_tx_t ret_dev = NET_XMIT_SUCCESS;
84 const struct bpf_mprog_entry *entry;
85 struct net_device *peer;
86 int len = skb->len;
87
88 bpf_net_ctx = bpf_net_ctx_set(bpf_net_ctx: &__bpf_net_ctx);
89 rcu_read_lock();
90 peer = rcu_dereference(nk->peer);
91 if (unlikely(!peer || !(peer->flags & IFF_UP) ||
92 !pskb_may_pull(skb, ETH_HLEN) ||
93 skb_orphan_frags(skb, GFP_ATOMIC)))
94 goto drop;
95 netkit_prep_forward(skb, xnet: !net_eq(net1: dev_net(dev), net2: dev_net(dev: peer)),
96 xnet_scrub: nk->scrub);
97 eth_skb_pkt_type(skb, dev: peer);
98 skb->dev = peer;
99 entry = rcu_dereference(nk->active);
100 if (entry)
101 ret = netkit_run(entry, skb, ret);
102 switch (ret) {
103 case NETKIT_NEXT:
104 case NETKIT_PASS:
105 eth_skb_pull_mac(skb);
106 skb_postpull_rcsum(skb, start: eth_hdr(skb), ETH_HLEN);
107 if (likely(__netif_rx(skb) == NET_RX_SUCCESS)) {
108 dev_sw_netstats_tx_add(dev, packets: 1, len);
109 dev_sw_netstats_rx_add(dev: peer, len);
110 } else {
111 goto drop_stats;
112 }
113 break;
114 case NETKIT_REDIRECT:
115 dev_sw_netstats_tx_add(dev, packets: 1, len);
116 skb_do_redirect(skb);
117 break;
118 case NETKIT_DROP:
119 default:
120drop:
121 kfree_skb(skb);
122drop_stats:
123 dev_core_stats_tx_dropped_inc(dev);
124 ret_dev = NET_XMIT_DROP;
125 break;
126 }
127 rcu_read_unlock();
128 bpf_net_ctx_clear(bpf_net_ctx);
129 return ret_dev;
130}
131
132static int netkit_open(struct net_device *dev)
133{
134 struct netkit *nk = netkit_priv(dev);
135 struct net_device *peer = rtnl_dereference(nk->peer);
136
137 if (!peer)
138 return -ENOTCONN;
139 if (peer->flags & IFF_UP) {
140 netif_carrier_on(dev);
141 netif_carrier_on(dev: peer);
142 }
143 return 0;
144}
145
146static int netkit_close(struct net_device *dev)
147{
148 struct netkit *nk = netkit_priv(dev);
149 struct net_device *peer = rtnl_dereference(nk->peer);
150
151 netif_carrier_off(dev);
152 if (peer)
153 netif_carrier_off(dev: peer);
154 return 0;
155}
156
157static int netkit_get_iflink(const struct net_device *dev)
158{
159 struct netkit *nk = netkit_priv(dev);
160 struct net_device *peer;
161 int iflink = 0;
162
163 rcu_read_lock();
164 peer = rcu_dereference(nk->peer);
165 if (peer)
166 iflink = READ_ONCE(peer->ifindex);
167 rcu_read_unlock();
168 return iflink;
169}
170
171static void netkit_set_multicast(struct net_device *dev)
172{
173 /* Nothing to do, we receive whatever gets pushed to us! */
174}
175
176static int netkit_set_macaddr(struct net_device *dev, void *sa)
177{
178 struct netkit *nk = netkit_priv(dev);
179
180 if (nk->mode != NETKIT_L2)
181 return -EOPNOTSUPP;
182
183 return eth_mac_addr(dev, p: sa);
184}
185
186static void netkit_set_headroom(struct net_device *dev, int headroom)
187{
188 struct netkit *nk = netkit_priv(dev), *nk2;
189 struct net_device *peer;
190
191 if (headroom < 0)
192 headroom = NET_SKB_PAD;
193
194 rcu_read_lock();
195 peer = rcu_dereference(nk->peer);
196 if (unlikely(!peer))
197 goto out;
198
199 nk2 = netkit_priv(dev: peer);
200 nk->headroom = headroom;
201 headroom = max(nk->headroom, nk2->headroom);
202
203 peer->needed_headroom = headroom;
204 dev->needed_headroom = headroom;
205out:
206 rcu_read_unlock();
207}
208
209INDIRECT_CALLABLE_SCOPE struct net_device *netkit_peer_dev(struct net_device *dev)
210{
211 return rcu_dereference(netkit_priv(dev)->peer);
212}
213
214static void netkit_get_stats(struct net_device *dev,
215 struct rtnl_link_stats64 *stats)
216{
217 dev_fetch_sw_netstats(s: stats, netstats: dev->tstats);
218 stats->tx_dropped = DEV_STATS_READ(dev, tx_dropped);
219}
220
221static void netkit_uninit(struct net_device *dev);
222
223static const struct net_device_ops netkit_netdev_ops = {
224 .ndo_open = netkit_open,
225 .ndo_stop = netkit_close,
226 .ndo_start_xmit = netkit_xmit,
227 .ndo_set_rx_mode = netkit_set_multicast,
228 .ndo_set_rx_headroom = netkit_set_headroom,
229 .ndo_set_mac_address = netkit_set_macaddr,
230 .ndo_get_iflink = netkit_get_iflink,
231 .ndo_get_peer_dev = netkit_peer_dev,
232 .ndo_get_stats64 = netkit_get_stats,
233 .ndo_uninit = netkit_uninit,
234 .ndo_features_check = passthru_features_check,
235};
236
237static void netkit_get_drvinfo(struct net_device *dev,
238 struct ethtool_drvinfo *info)
239{
240 strscpy(info->driver, DRV_NAME, sizeof(info->driver));
241}
242
243static const struct ethtool_ops netkit_ethtool_ops = {
244 .get_drvinfo = netkit_get_drvinfo,
245};
246
247static void netkit_setup(struct net_device *dev)
248{
249 static const netdev_features_t netkit_features_hw_vlan =
250 NETIF_F_HW_VLAN_CTAG_TX |
251 NETIF_F_HW_VLAN_CTAG_RX |
252 NETIF_F_HW_VLAN_STAG_TX |
253 NETIF_F_HW_VLAN_STAG_RX;
254 static const netdev_features_t netkit_features =
255 netkit_features_hw_vlan |
256 NETIF_F_SG |
257 NETIF_F_FRAGLIST |
258 NETIF_F_HW_CSUM |
259 NETIF_F_RXCSUM |
260 NETIF_F_SCTP_CRC |
261 NETIF_F_HIGHDMA |
262 NETIF_F_GSO_SOFTWARE |
263 NETIF_F_GSO_ENCAP_ALL;
264
265 ether_setup(dev);
266 dev->max_mtu = ETH_MAX_MTU;
267 dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
268
269 dev->flags |= IFF_NOARP;
270 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
271 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
272 dev->priv_flags |= IFF_PHONY_HEADROOM;
273 dev->priv_flags |= IFF_NO_QUEUE;
274 dev->priv_flags |= IFF_DISABLE_NETPOLL;
275 dev->lltx = true;
276
277 dev->ethtool_ops = &netkit_ethtool_ops;
278 dev->netdev_ops = &netkit_netdev_ops;
279
280 dev->features |= netkit_features;
281 dev->hw_features = netkit_features;
282 dev->hw_enc_features = netkit_features;
283 dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
284 dev->vlan_features = dev->features & ~netkit_features_hw_vlan;
285
286 dev->needs_free_netdev = true;
287
288 netif_set_tso_max_size(dev, GSO_MAX_SIZE);
289}
290
291static struct net *netkit_get_link_net(const struct net_device *dev)
292{
293 struct netkit *nk = netkit_priv(dev);
294 struct net_device *peer = rtnl_dereference(nk->peer);
295
296 return peer ? dev_net(dev: peer) : dev_net(dev);
297}
298
299static int netkit_check_policy(int policy, struct nlattr *tb,
300 struct netlink_ext_ack *extack)
301{
302 switch (policy) {
303 case NETKIT_PASS:
304 case NETKIT_DROP:
305 return 0;
306 default:
307 NL_SET_ERR_MSG_ATTR(extack, tb,
308 "Provided default xmit policy not supported");
309 return -EINVAL;
310 }
311}
312
313static int netkit_validate(struct nlattr *tb[], struct nlattr *data[],
314 struct netlink_ext_ack *extack)
315{
316 struct nlattr *attr = tb[IFLA_ADDRESS];
317
318 if (!attr)
319 return 0;
320 if (nla_len(nla: attr) != ETH_ALEN)
321 return -EINVAL;
322 if (!is_valid_ether_addr(addr: nla_data(nla: attr)))
323 return -EADDRNOTAVAIL;
324 return 0;
325}
326
327static struct rtnl_link_ops netkit_link_ops;
328
329static int netkit_new_link(struct net_device *dev,
330 struct rtnl_newlink_params *params,
331 struct netlink_ext_ack *extack)
332{
333 struct net *peer_net = rtnl_newlink_peer_net(p: params);
334 enum netkit_scrub scrub_prim = NETKIT_SCRUB_DEFAULT;
335 enum netkit_scrub scrub_peer = NETKIT_SCRUB_DEFAULT;
336 struct nlattr *peer_tb[IFLA_MAX + 1], **tbp, *attr;
337 enum netkit_action policy_prim = NETKIT_PASS;
338 enum netkit_action policy_peer = NETKIT_PASS;
339 struct nlattr **data = params->data;
340 enum netkit_mode mode = NETKIT_L3;
341 unsigned char ifname_assign_type;
342 struct nlattr **tb = params->tb;
343 u16 headroom = 0, tailroom = 0;
344 struct ifinfomsg *ifmp = NULL;
345 struct net_device *peer;
346 char ifname[IFNAMSIZ];
347 struct netkit *nk;
348 int err;
349
350 tbp = tb;
351 if (data) {
352 if (data[IFLA_NETKIT_MODE])
353 mode = nla_get_u32(nla: data[IFLA_NETKIT_MODE]);
354 if (data[IFLA_NETKIT_PEER_INFO]) {
355 attr = data[IFLA_NETKIT_PEER_INFO];
356 ifmp = nla_data(nla: attr);
357 rtnl_nla_parse_ifinfomsg(tb: peer_tb, nla_peer: attr, exterr: extack);
358 tbp = peer_tb;
359 }
360 if (data[IFLA_NETKIT_SCRUB])
361 scrub_prim = nla_get_u32(nla: data[IFLA_NETKIT_SCRUB]);
362 if (data[IFLA_NETKIT_PEER_SCRUB])
363 scrub_peer = nla_get_u32(nla: data[IFLA_NETKIT_PEER_SCRUB]);
364 if (data[IFLA_NETKIT_POLICY]) {
365 attr = data[IFLA_NETKIT_POLICY];
366 policy_prim = nla_get_u32(nla: attr);
367 err = netkit_check_policy(policy: policy_prim, tb: attr, extack);
368 if (err < 0)
369 return err;
370 }
371 if (data[IFLA_NETKIT_PEER_POLICY]) {
372 attr = data[IFLA_NETKIT_PEER_POLICY];
373 policy_peer = nla_get_u32(nla: attr);
374 err = netkit_check_policy(policy: policy_peer, tb: attr, extack);
375 if (err < 0)
376 return err;
377 }
378 if (data[IFLA_NETKIT_HEADROOM])
379 headroom = nla_get_u16(nla: data[IFLA_NETKIT_HEADROOM]);
380 if (data[IFLA_NETKIT_TAILROOM])
381 tailroom = nla_get_u16(nla: data[IFLA_NETKIT_TAILROOM]);
382 }
383
384 if (ifmp && tbp[IFLA_IFNAME]) {
385 nla_strscpy(dst: ifname, nla: tbp[IFLA_IFNAME], IFNAMSIZ);
386 ifname_assign_type = NET_NAME_USER;
387 } else {
388 strscpy(ifname, "nk%d", IFNAMSIZ);
389 ifname_assign_type = NET_NAME_ENUM;
390 }
391 if (mode != NETKIT_L2 &&
392 (tb[IFLA_ADDRESS] || tbp[IFLA_ADDRESS]))
393 return -EOPNOTSUPP;
394
395 peer = rtnl_create_link(net: peer_net, ifname, name_assign_type: ifname_assign_type,
396 ops: &netkit_link_ops, tb: tbp, extack);
397 if (IS_ERR(ptr: peer))
398 return PTR_ERR(ptr: peer);
399
400 netif_inherit_tso_max(to: peer, from: dev);
401 if (headroom) {
402 peer->needed_headroom = headroom;
403 dev->needed_headroom = headroom;
404 }
405 if (tailroom) {
406 peer->needed_tailroom = tailroom;
407 dev->needed_tailroom = tailroom;
408 }
409
410 if (mode == NETKIT_L2 && !(ifmp && tbp[IFLA_ADDRESS]))
411 eth_hw_addr_random(dev: peer);
412 if (ifmp && dev->ifindex)
413 peer->ifindex = ifmp->ifi_index;
414
415 nk = netkit_priv(dev: peer);
416 nk->primary = false;
417 nk->policy = policy_peer;
418 nk->scrub = scrub_peer;
419 nk->mode = mode;
420 nk->headroom = headroom;
421 bpf_mprog_bundle_init(bundle: &nk->bundle);
422
423 err = register_netdevice(dev: peer);
424 if (err < 0)
425 goto err_register_peer;
426 netif_carrier_off(dev: peer);
427 if (mode == NETKIT_L2)
428 dev_change_flags(dev: peer, flags: peer->flags & ~IFF_NOARP, NULL);
429
430 err = rtnl_configure_link(dev: peer, NULL, portid: 0, NULL);
431 if (err < 0)
432 goto err_configure_peer;
433
434 if (mode == NETKIT_L2 && !tb[IFLA_ADDRESS])
435 eth_hw_addr_random(dev);
436 if (tb[IFLA_IFNAME])
437 nla_strscpy(dst: dev->name, nla: tb[IFLA_IFNAME], IFNAMSIZ);
438 else
439 strscpy(dev->name, "nk%d", IFNAMSIZ);
440
441 nk = netkit_priv(dev);
442 nk->primary = true;
443 nk->policy = policy_prim;
444 nk->scrub = scrub_prim;
445 nk->mode = mode;
446 nk->headroom = headroom;
447 bpf_mprog_bundle_init(bundle: &nk->bundle);
448
449 err = register_netdevice(dev);
450 if (err < 0)
451 goto err_configure_peer;
452 netif_carrier_off(dev);
453 if (mode == NETKIT_L2)
454 dev_change_flags(dev, flags: dev->flags & ~IFF_NOARP, NULL);
455
456 rcu_assign_pointer(netkit_priv(dev)->peer, peer);
457 rcu_assign_pointer(netkit_priv(peer)->peer, dev);
458 return 0;
459err_configure_peer:
460 unregister_netdevice(dev: peer);
461 return err;
462err_register_peer:
463 free_netdev(dev: peer);
464 return err;
465}
466
467static struct bpf_mprog_entry *netkit_entry_fetch(struct net_device *dev,
468 bool bundle_fallback)
469{
470 struct netkit *nk = netkit_priv(dev);
471 struct bpf_mprog_entry *entry;
472
473 ASSERT_RTNL();
474 entry = rcu_dereference_rtnl(nk->active);
475 if (entry)
476 return entry;
477 if (bundle_fallback)
478 return &nk->bundle.a;
479 return NULL;
480}
481
482static void netkit_entry_update(struct net_device *dev,
483 struct bpf_mprog_entry *entry)
484{
485 struct netkit *nk = netkit_priv(dev);
486
487 ASSERT_RTNL();
488 rcu_assign_pointer(nk->active, entry);
489}
490
491static void netkit_entry_sync(void)
492{
493 synchronize_rcu();
494}
495
496static struct net_device *netkit_dev_fetch(struct net *net, u32 ifindex, u32 which)
497{
498 struct net_device *dev;
499 struct netkit *nk;
500
501 ASSERT_RTNL();
502
503 switch (which) {
504 case BPF_NETKIT_PRIMARY:
505 case BPF_NETKIT_PEER:
506 break;
507 default:
508 return ERR_PTR(error: -EINVAL);
509 }
510
511 dev = __dev_get_by_index(net, ifindex);
512 if (!dev)
513 return ERR_PTR(error: -ENODEV);
514 if (dev->netdev_ops != &netkit_netdev_ops)
515 return ERR_PTR(error: -ENXIO);
516
517 nk = netkit_priv(dev);
518 if (!nk->primary)
519 return ERR_PTR(error: -EACCES);
520 if (which == BPF_NETKIT_PEER) {
521 dev = rcu_dereference_rtnl(nk->peer);
522 if (!dev)
523 return ERR_PTR(error: -ENODEV);
524 }
525 return dev;
526}
527
528int netkit_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)
529{
530 struct bpf_mprog_entry *entry, *entry_new;
531 struct bpf_prog *replace_prog = NULL;
532 struct net_device *dev;
533 int ret;
534
535 rtnl_lock();
536 dev = netkit_dev_fetch(current->nsproxy->net_ns, ifindex: attr->target_ifindex,
537 which: attr->attach_type);
538 if (IS_ERR(ptr: dev)) {
539 ret = PTR_ERR(ptr: dev);
540 goto out;
541 }
542 entry = netkit_entry_fetch(dev, bundle_fallback: true);
543 if (attr->attach_flags & BPF_F_REPLACE) {
544 replace_prog = bpf_prog_get_type(ufd: attr->replace_bpf_fd,
545 type: prog->type);
546 if (IS_ERR(ptr: replace_prog)) {
547 ret = PTR_ERR(ptr: replace_prog);
548 replace_prog = NULL;
549 goto out;
550 }
551 }
552 ret = bpf_mprog_attach(entry, entry_new: &entry_new, prog_new: prog, NULL, prog_old: replace_prog,
553 flags: attr->attach_flags, id_or_fd: attr->relative_fd,
554 revision: attr->expected_revision);
555 if (!ret) {
556 if (entry != entry_new) {
557 netkit_entry_update(dev, entry: entry_new);
558 netkit_entry_sync();
559 }
560 bpf_mprog_commit(entry);
561 }
562out:
563 if (replace_prog)
564 bpf_prog_put(prog: replace_prog);
565 rtnl_unlock();
566 return ret;
567}
568
569int netkit_prog_detach(const union bpf_attr *attr, struct bpf_prog *prog)
570{
571 struct bpf_mprog_entry *entry, *entry_new;
572 struct net_device *dev;
573 int ret;
574
575 rtnl_lock();
576 dev = netkit_dev_fetch(current->nsproxy->net_ns, ifindex: attr->target_ifindex,
577 which: attr->attach_type);
578 if (IS_ERR(ptr: dev)) {
579 ret = PTR_ERR(ptr: dev);
580 goto out;
581 }
582 entry = netkit_entry_fetch(dev, bundle_fallback: false);
583 if (!entry) {
584 ret = -ENOENT;
585 goto out;
586 }
587 ret = bpf_mprog_detach(entry, entry_new: &entry_new, prog, NULL, flags: attr->attach_flags,
588 id_or_fd: attr->relative_fd, revision: attr->expected_revision);
589 if (!ret) {
590 if (!bpf_mprog_total(entry: entry_new))
591 entry_new = NULL;
592 netkit_entry_update(dev, entry: entry_new);
593 netkit_entry_sync();
594 bpf_mprog_commit(entry);
595 }
596out:
597 rtnl_unlock();
598 return ret;
599}
600
601int netkit_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr)
602{
603 struct net_device *dev;
604 int ret;
605
606 rtnl_lock();
607 dev = netkit_dev_fetch(current->nsproxy->net_ns,
608 ifindex: attr->query.target_ifindex,
609 which: attr->query.attach_type);
610 if (IS_ERR(ptr: dev)) {
611 ret = PTR_ERR(ptr: dev);
612 goto out;
613 }
614 ret = bpf_mprog_query(attr, uattr, entry: netkit_entry_fetch(dev, bundle_fallback: false));
615out:
616 rtnl_unlock();
617 return ret;
618}
619
620static struct netkit_link *netkit_link(const struct bpf_link *link)
621{
622 return container_of(link, struct netkit_link, link);
623}
624
625static int netkit_link_prog_attach(struct bpf_link *link, u32 flags,
626 u32 id_or_fd, u64 revision)
627{
628 struct netkit_link *nkl = netkit_link(link);
629 struct bpf_mprog_entry *entry, *entry_new;
630 struct net_device *dev = nkl->dev;
631 int ret;
632
633 ASSERT_RTNL();
634 entry = netkit_entry_fetch(dev, bundle_fallback: true);
635 ret = bpf_mprog_attach(entry, entry_new: &entry_new, prog_new: link->prog, link, NULL, flags,
636 id_or_fd, revision);
637 if (!ret) {
638 if (entry != entry_new) {
639 netkit_entry_update(dev, entry: entry_new);
640 netkit_entry_sync();
641 }
642 bpf_mprog_commit(entry);
643 }
644 return ret;
645}
646
647static void netkit_link_release(struct bpf_link *link)
648{
649 struct netkit_link *nkl = netkit_link(link);
650 struct bpf_mprog_entry *entry, *entry_new;
651 struct net_device *dev;
652 int ret = 0;
653
654 rtnl_lock();
655 dev = nkl->dev;
656 if (!dev)
657 goto out;
658 entry = netkit_entry_fetch(dev, bundle_fallback: false);
659 if (!entry) {
660 ret = -ENOENT;
661 goto out;
662 }
663 ret = bpf_mprog_detach(entry, entry_new: &entry_new, prog: link->prog, link, flags: 0, id_or_fd: 0, revision: 0);
664 if (!ret) {
665 if (!bpf_mprog_total(entry: entry_new))
666 entry_new = NULL;
667 netkit_entry_update(dev, entry: entry_new);
668 netkit_entry_sync();
669 bpf_mprog_commit(entry);
670 nkl->dev = NULL;
671 }
672out:
673 WARN_ON_ONCE(ret);
674 rtnl_unlock();
675}
676
677static int netkit_link_update(struct bpf_link *link, struct bpf_prog *nprog,
678 struct bpf_prog *oprog)
679{
680 struct netkit_link *nkl = netkit_link(link);
681 struct bpf_mprog_entry *entry, *entry_new;
682 struct net_device *dev;
683 int ret = 0;
684
685 rtnl_lock();
686 dev = nkl->dev;
687 if (!dev) {
688 ret = -ENOLINK;
689 goto out;
690 }
691 if (oprog && link->prog != oprog) {
692 ret = -EPERM;
693 goto out;
694 }
695 oprog = link->prog;
696 if (oprog == nprog) {
697 bpf_prog_put(prog: nprog);
698 goto out;
699 }
700 entry = netkit_entry_fetch(dev, bundle_fallback: false);
701 if (!entry) {
702 ret = -ENOENT;
703 goto out;
704 }
705 ret = bpf_mprog_attach(entry, entry_new: &entry_new, prog_new: nprog, link, prog_old: oprog,
706 BPF_F_REPLACE | BPF_F_ID,
707 id_or_fd: link->prog->aux->id, revision: 0);
708 if (!ret) {
709 WARN_ON_ONCE(entry != entry_new);
710 oprog = xchg(&link->prog, nprog);
711 bpf_prog_put(prog: oprog);
712 bpf_mprog_commit(entry);
713 }
714out:
715 rtnl_unlock();
716 return ret;
717}
718
719static void netkit_link_dealloc(struct bpf_link *link)
720{
721 kfree(objp: netkit_link(link));
722}
723
724static void netkit_link_fdinfo(const struct bpf_link *link, struct seq_file *seq)
725{
726 const struct netkit_link *nkl = netkit_link(link);
727 u32 ifindex = 0;
728
729 rtnl_lock();
730 if (nkl->dev)
731 ifindex = nkl->dev->ifindex;
732 rtnl_unlock();
733
734 seq_printf(m: seq, fmt: "ifindex:\t%u\n", ifindex);
735 seq_printf(m: seq, fmt: "attach_type:\t%u (%s)\n",
736 nkl->location,
737 nkl->location == BPF_NETKIT_PRIMARY ? "primary" : "peer");
738}
739
740static int netkit_link_fill_info(const struct bpf_link *link,
741 struct bpf_link_info *info)
742{
743 const struct netkit_link *nkl = netkit_link(link);
744 u32 ifindex = 0;
745
746 rtnl_lock();
747 if (nkl->dev)
748 ifindex = nkl->dev->ifindex;
749 rtnl_unlock();
750
751 info->netkit.ifindex = ifindex;
752 info->netkit.attach_type = nkl->location;
753 return 0;
754}
755
756static int netkit_link_detach(struct bpf_link *link)
757{
758 netkit_link_release(link);
759 return 0;
760}
761
762static const struct bpf_link_ops netkit_link_lops = {
763 .release = netkit_link_release,
764 .detach = netkit_link_detach,
765 .dealloc = netkit_link_dealloc,
766 .update_prog = netkit_link_update,
767 .show_fdinfo = netkit_link_fdinfo,
768 .fill_link_info = netkit_link_fill_info,
769};
770
771static int netkit_link_init(struct netkit_link *nkl,
772 struct bpf_link_primer *link_primer,
773 const union bpf_attr *attr,
774 struct net_device *dev,
775 struct bpf_prog *prog)
776{
777 bpf_link_init(link: &nkl->link, type: BPF_LINK_TYPE_NETKIT,
778 ops: &netkit_link_lops, prog);
779 nkl->location = attr->link_create.attach_type;
780 nkl->dev = dev;
781 return bpf_link_prime(link: &nkl->link, primer: link_primer);
782}
783
784int netkit_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
785{
786 struct bpf_link_primer link_primer;
787 struct netkit_link *nkl;
788 struct net_device *dev;
789 int ret;
790
791 rtnl_lock();
792 dev = netkit_dev_fetch(current->nsproxy->net_ns,
793 ifindex: attr->link_create.target_ifindex,
794 which: attr->link_create.attach_type);
795 if (IS_ERR(ptr: dev)) {
796 ret = PTR_ERR(ptr: dev);
797 goto out;
798 }
799 nkl = kzalloc(sizeof(*nkl), GFP_KERNEL_ACCOUNT);
800 if (!nkl) {
801 ret = -ENOMEM;
802 goto out;
803 }
804 ret = netkit_link_init(nkl, link_primer: &link_primer, attr, dev, prog);
805 if (ret) {
806 kfree(objp: nkl);
807 goto out;
808 }
809 ret = netkit_link_prog_attach(link: &nkl->link,
810 flags: attr->link_create.flags,
811 id_or_fd: attr->link_create.netkit.relative_fd,
812 revision: attr->link_create.netkit.expected_revision);
813 if (ret) {
814 nkl->dev = NULL;
815 bpf_link_cleanup(primer: &link_primer);
816 goto out;
817 }
818 ret = bpf_link_settle(primer: &link_primer);
819out:
820 rtnl_unlock();
821 return ret;
822}
823
824static void netkit_release_all(struct net_device *dev)
825{
826 struct bpf_mprog_entry *entry;
827 struct bpf_tuple tuple = {};
828 struct bpf_mprog_fp *fp;
829 struct bpf_mprog_cp *cp;
830
831 entry = netkit_entry_fetch(dev, bundle_fallback: false);
832 if (!entry)
833 return;
834 netkit_entry_update(dev, NULL);
835 netkit_entry_sync();
836 bpf_mprog_foreach_tuple(entry, fp, cp, tuple) {
837 if (tuple.link)
838 netkit_link(link: tuple.link)->dev = NULL;
839 else
840 bpf_prog_put(prog: tuple.prog);
841 }
842}
843
844static void netkit_uninit(struct net_device *dev)
845{
846 netkit_release_all(dev);
847}
848
849static void netkit_del_link(struct net_device *dev, struct list_head *head)
850{
851 struct netkit *nk = netkit_priv(dev);
852 struct net_device *peer = rtnl_dereference(nk->peer);
853
854 RCU_INIT_POINTER(nk->peer, NULL);
855 unregister_netdevice_queue(dev, head);
856 if (peer) {
857 nk = netkit_priv(dev: peer);
858 RCU_INIT_POINTER(nk->peer, NULL);
859 unregister_netdevice_queue(dev: peer, head);
860 }
861}
862
863static int netkit_change_link(struct net_device *dev, struct nlattr *tb[],
864 struct nlattr *data[],
865 struct netlink_ext_ack *extack)
866{
867 struct netkit *nk = netkit_priv(dev);
868 struct net_device *peer = rtnl_dereference(nk->peer);
869 enum netkit_action policy;
870 struct nlattr *attr;
871 int err, i;
872 static const struct {
873 u32 attr;
874 char *name;
875 } fixed_params[] = {
876 { IFLA_NETKIT_MODE, "operating mode" },
877 { IFLA_NETKIT_SCRUB, "scrubbing" },
878 { IFLA_NETKIT_PEER_SCRUB, "peer scrubbing" },
879 { IFLA_NETKIT_PEER_INFO, "peer info" },
880 { IFLA_NETKIT_HEADROOM, "headroom" },
881 { IFLA_NETKIT_TAILROOM, "tailroom" },
882 };
883
884 if (!nk->primary) {
885 NL_SET_ERR_MSG(extack,
886 "netkit link settings can be changed only through the primary device");
887 return -EACCES;
888 }
889
890 for (i = 0; i < ARRAY_SIZE(fixed_params); i++) {
891 attr = data[fixed_params[i].attr];
892 if (attr) {
893 NL_SET_ERR_MSG_ATTR_FMT(extack, attr,
894 "netkit link %s cannot be changed after device creation",
895 fixed_params[i].name);
896 return -EACCES;
897 }
898 }
899
900 if (data[IFLA_NETKIT_POLICY]) {
901 attr = data[IFLA_NETKIT_POLICY];
902 policy = nla_get_u32(nla: attr);
903 err = netkit_check_policy(policy, tb: attr, extack);
904 if (err)
905 return err;
906 WRITE_ONCE(nk->policy, policy);
907 }
908
909 if (data[IFLA_NETKIT_PEER_POLICY]) {
910 err = -EOPNOTSUPP;
911 attr = data[IFLA_NETKIT_PEER_POLICY];
912 policy = nla_get_u32(nla: attr);
913 if (peer)
914 err = netkit_check_policy(policy, tb: attr, extack);
915 if (err)
916 return err;
917 nk = netkit_priv(dev: peer);
918 WRITE_ONCE(nk->policy, policy);
919 }
920
921 return 0;
922}
923
924static size_t netkit_get_size(const struct net_device *dev)
925{
926 return nla_total_size(payload: sizeof(u32)) + /* IFLA_NETKIT_POLICY */
927 nla_total_size(payload: sizeof(u32)) + /* IFLA_NETKIT_PEER_POLICY */
928 nla_total_size(payload: sizeof(u32)) + /* IFLA_NETKIT_SCRUB */
929 nla_total_size(payload: sizeof(u32)) + /* IFLA_NETKIT_PEER_SCRUB */
930 nla_total_size(payload: sizeof(u32)) + /* IFLA_NETKIT_MODE */
931 nla_total_size(payload: sizeof(u8)) + /* IFLA_NETKIT_PRIMARY */
932 nla_total_size(payload: sizeof(u16)) + /* IFLA_NETKIT_HEADROOM */
933 nla_total_size(payload: sizeof(u16)) + /* IFLA_NETKIT_TAILROOM */
934 0;
935}
936
937static int netkit_fill_info(struct sk_buff *skb, const struct net_device *dev)
938{
939 struct netkit *nk = netkit_priv(dev);
940 struct net_device *peer = rtnl_dereference(nk->peer);
941
942 if (nla_put_u8(skb, attrtype: IFLA_NETKIT_PRIMARY, value: nk->primary))
943 return -EMSGSIZE;
944 if (nla_put_u32(skb, attrtype: IFLA_NETKIT_POLICY, value: nk->policy))
945 return -EMSGSIZE;
946 if (nla_put_u32(skb, attrtype: IFLA_NETKIT_MODE, value: nk->mode))
947 return -EMSGSIZE;
948 if (nla_put_u32(skb, attrtype: IFLA_NETKIT_SCRUB, value: nk->scrub))
949 return -EMSGSIZE;
950 if (nla_put_u16(skb, attrtype: IFLA_NETKIT_HEADROOM, value: dev->needed_headroom))
951 return -EMSGSIZE;
952 if (nla_put_u16(skb, attrtype: IFLA_NETKIT_TAILROOM, value: dev->needed_tailroom))
953 return -EMSGSIZE;
954
955 if (peer) {
956 nk = netkit_priv(dev: peer);
957 if (nla_put_u32(skb, attrtype: IFLA_NETKIT_PEER_POLICY, value: nk->policy))
958 return -EMSGSIZE;
959 if (nla_put_u32(skb, attrtype: IFLA_NETKIT_PEER_SCRUB, value: nk->scrub))
960 return -EMSGSIZE;
961 }
962
963 return 0;
964}
965
966static const struct nla_policy netkit_policy[IFLA_NETKIT_MAX + 1] = {
967 [IFLA_NETKIT_PEER_INFO] = { .len = sizeof(struct ifinfomsg) },
968 [IFLA_NETKIT_MODE] = NLA_POLICY_MAX(NLA_U32, NETKIT_L3),
969 [IFLA_NETKIT_POLICY] = { .type = NLA_U32 },
970 [IFLA_NETKIT_PEER_POLICY] = { .type = NLA_U32 },
971 [IFLA_NETKIT_HEADROOM] = { .type = NLA_U16 },
972 [IFLA_NETKIT_TAILROOM] = { .type = NLA_U16 },
973 [IFLA_NETKIT_SCRUB] = NLA_POLICY_MAX(NLA_U32, NETKIT_SCRUB_DEFAULT),
974 [IFLA_NETKIT_PEER_SCRUB] = NLA_POLICY_MAX(NLA_U32, NETKIT_SCRUB_DEFAULT),
975 [IFLA_NETKIT_PRIMARY] = { .type = NLA_REJECT,
976 .reject_message = "Primary attribute is read-only" },
977};
978
979static struct rtnl_link_ops netkit_link_ops = {
980 .kind = DRV_NAME,
981 .priv_size = sizeof(struct netkit),
982 .setup = netkit_setup,
983 .newlink = netkit_new_link,
984 .dellink = netkit_del_link,
985 .changelink = netkit_change_link,
986 .get_link_net = netkit_get_link_net,
987 .get_size = netkit_get_size,
988 .fill_info = netkit_fill_info,
989 .policy = netkit_policy,
990 .validate = netkit_validate,
991 .peer_type = IFLA_NETKIT_PEER_INFO,
992 .maxtype = IFLA_NETKIT_MAX,
993};
994
995static __init int netkit_init(void)
996{
997 BUILD_BUG_ON((int)NETKIT_NEXT != (int)TCX_NEXT ||
998 (int)NETKIT_PASS != (int)TCX_PASS ||
999 (int)NETKIT_DROP != (int)TCX_DROP ||
1000 (int)NETKIT_REDIRECT != (int)TCX_REDIRECT);
1001
1002 return rtnl_link_register(ops: &netkit_link_ops);
1003}
1004
1005static __exit void netkit_exit(void)
1006{
1007 rtnl_link_unregister(ops: &netkit_link_ops);
1008}
1009
1010module_init(netkit_init);
1011module_exit(netkit_exit);
1012
1013MODULE_DESCRIPTION("BPF-programmable network device");
1014MODULE_AUTHOR("Daniel Borkmann <daniel@iogearbox.net>");
1015MODULE_AUTHOR("Nikolay Aleksandrov <razor@blackwall.org>");
1016MODULE_LICENSE("GPL");
1017MODULE_ALIAS_RTNL_LINK(DRV_NAME);
1018

source code of linux/drivers/net/netkit.c