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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 struct bpf_mprog_bundle bundle;
24
25 /* Needed in slow-path */
26 enum netkit_mode mode;
27 bool primary;
28 u32 headroom;
29};
30
31struct netkit_link {
32 struct bpf_link link;
33 struct net_device *dev;
34 u32 location;
35};
36
37static __always_inline int
38netkit_run(const struct bpf_mprog_entry *entry, struct sk_buff *skb,
39 enum netkit_action ret)
40{
41 const struct bpf_mprog_fp *fp;
42 const struct bpf_prog *prog;
43
44 bpf_mprog_foreach_prog(entry, fp, prog) {
45 bpf_compute_data_pointers(skb);
46 ret = bpf_prog_run(prog, skb);
47 if (ret != NETKIT_NEXT)
48 break;
49 }
50 return ret;
51}
52
53static void netkit_prep_forward(struct sk_buff *skb, bool xnet)
54{
55 skb_scrub_packet(skb, xnet);
56 skb->priority = 0;
57 nf_skip_egress(skb, true);
58 skb_reset_mac_header(skb);
59}
60
61static struct netkit *netkit_priv(const struct net_device *dev)
62{
63 return netdev_priv(dev);
64}
65
66static netdev_tx_t netkit_xmit(struct sk_buff *skb, struct net_device *dev)
67{
68 struct netkit *nk = netkit_priv(dev);
69 enum netkit_action ret = READ_ONCE(nk->policy);
70 netdev_tx_t ret_dev = NET_XMIT_SUCCESS;
71 const struct bpf_mprog_entry *entry;
72 struct net_device *peer;
73 int len = skb->len;
74
75 rcu_read_lock();
76 peer = rcu_dereference(nk->peer);
77 if (unlikely(!peer || !(peer->flags & IFF_UP) ||
78 !pskb_may_pull(skb, ETH_HLEN) ||
79 skb_orphan_frags(skb, GFP_ATOMIC)))
80 goto drop;
81 netkit_prep_forward(skb, !net_eq(dev_net(dev), dev_net(peer)));
82 eth_skb_pkt_type(skb, peer);
83 skb->dev = peer;
84 entry = rcu_dereference(nk->active);
85 if (entry)
86 ret = netkit_run(entry, skb, ret);
87 switch (ret) {
88 case NETKIT_NEXT:
89 case NETKIT_PASS:
90 eth_skb_pull_mac(skb);
91 skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
92 if (likely(__netif_rx(skb) == NET_RX_SUCCESS)) {
93 dev_sw_netstats_tx_add(dev, 1, len);
94 dev_sw_netstats_rx_add(peer, len);
95 } else {
96 goto drop_stats;
97 }
98 break;
99 case NETKIT_REDIRECT:
100 dev_sw_netstats_tx_add(dev, 1, len);
101 skb_do_redirect(skb);
102 break;
103 case NETKIT_DROP:
104 default:
105drop:
106 kfree_skb(skb);
107drop_stats:
108 dev_core_stats_tx_dropped_inc(dev);
109 ret_dev = NET_XMIT_DROP;
110 break;
111 }
112 rcu_read_unlock();
113 return ret_dev;
114}
115
116static int netkit_open(struct net_device *dev)
117{
118 struct netkit *nk = netkit_priv(dev);
119 struct net_device *peer = rtnl_dereference(nk->peer);
120
121 if (!peer)
122 return -ENOTCONN;
123 if (peer->flags & IFF_UP) {
124 netif_carrier_on(dev);
125 netif_carrier_on(peer);
126 }
127 return 0;
128}
129
130static int netkit_close(struct net_device *dev)
131{
132 struct netkit *nk = netkit_priv(dev);
133 struct net_device *peer = rtnl_dereference(nk->peer);
134
135 netif_carrier_off(dev);
136 if (peer)
137 netif_carrier_off(peer);
138 return 0;
139}
140
141static int netkit_get_iflink(const struct net_device *dev)
142{
143 struct netkit *nk = netkit_priv(dev);
144 struct net_device *peer;
145 int iflink = 0;
146
147 rcu_read_lock();
148 peer = rcu_dereference(nk->peer);
149 if (peer)
150 iflink = READ_ONCE(peer->ifindex);
151 rcu_read_unlock();
152 return iflink;
153}
154
155static void netkit_set_multicast(struct net_device *dev)
156{
157 /* Nothing to do, we receive whatever gets pushed to us! */
158}
159
160static int netkit_set_macaddr(struct net_device *dev, void *sa)
161{
162 struct netkit *nk = netkit_priv(dev);
163
164 if (nk->mode != NETKIT_L2)
165 return -EOPNOTSUPP;
166
167 return eth_mac_addr(dev, sa);
168}
169
170static void netkit_set_headroom(struct net_device *dev, int headroom)
171{
172 struct netkit *nk = netkit_priv(dev), *nk2;
173 struct net_device *peer;
174
175 if (headroom < 0)
176 headroom = NET_SKB_PAD;
177
178 rcu_read_lock();
179 peer = rcu_dereference(nk->peer);
180 if (unlikely(!peer))
181 goto out;
182
183 nk2 = netkit_priv(peer);
184 nk->headroom = headroom;
185 headroom = max(nk->headroom, nk2->headroom);
186
187 peer->needed_headroom = headroom;
188 dev->needed_headroom = headroom;
189out:
190 rcu_read_unlock();
191}
192
193INDIRECT_CALLABLE_SCOPE struct net_device *netkit_peer_dev(struct net_device *dev)
194{
195 return rcu_dereference(netkit_priv(dev)->peer);
196}
197
198static void netkit_get_stats(struct net_device *dev,
199 struct rtnl_link_stats64 *stats)
200{
201 dev_fetch_sw_netstats(stats, dev->tstats);
202 stats->tx_dropped = DEV_STATS_READ(dev, tx_dropped);
203}
204
205static void netkit_uninit(struct net_device *dev);
206
207static const struct net_device_ops netkit_netdev_ops = {
208 .ndo_open = netkit_open,
209 .ndo_stop = netkit_close,
210 .ndo_start_xmit = netkit_xmit,
211 .ndo_set_rx_mode = netkit_set_multicast,
212 .ndo_set_rx_headroom = netkit_set_headroom,
213 .ndo_set_mac_address = netkit_set_macaddr,
214 .ndo_get_iflink = netkit_get_iflink,
215 .ndo_get_peer_dev = netkit_peer_dev,
216 .ndo_get_stats64 = netkit_get_stats,
217 .ndo_uninit = netkit_uninit,
218 .ndo_features_check = passthru_features_check,
219};
220
221static void netkit_get_drvinfo(struct net_device *dev,
222 struct ethtool_drvinfo *info)
223{
224 strscpy(info->driver, DRV_NAME, sizeof(info->driver));
225}
226
227static const struct ethtool_ops netkit_ethtool_ops = {
228 .get_drvinfo = netkit_get_drvinfo,
229};
230
231static void netkit_setup(struct net_device *dev)
232{
233 static const netdev_features_t netkit_features_hw_vlan =
234 NETIF_F_HW_VLAN_CTAG_TX |
235 NETIF_F_HW_VLAN_CTAG_RX |
236 NETIF_F_HW_VLAN_STAG_TX |
237 NETIF_F_HW_VLAN_STAG_RX;
238 static const netdev_features_t netkit_features =
239 netkit_features_hw_vlan |
240 NETIF_F_SG |
241 NETIF_F_FRAGLIST |
242 NETIF_F_HW_CSUM |
243 NETIF_F_RXCSUM |
244 NETIF_F_SCTP_CRC |
245 NETIF_F_HIGHDMA |
246 NETIF_F_GSO_SOFTWARE |
247 NETIF_F_GSO_ENCAP_ALL;
248
249 ether_setup(dev);
250 dev->max_mtu = ETH_MAX_MTU;
251 dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
252
253 dev->flags |= IFF_NOARP;
254 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
255 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
256 dev->priv_flags |= IFF_PHONY_HEADROOM;
257 dev->priv_flags |= IFF_NO_QUEUE;
258
259 dev->ethtool_ops = &netkit_ethtool_ops;
260 dev->netdev_ops = &netkit_netdev_ops;
261
262 dev->features |= netkit_features | NETIF_F_LLTX;
263 dev->hw_features = netkit_features;
264 dev->hw_enc_features = netkit_features;
265 dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
266 dev->vlan_features = dev->features & ~netkit_features_hw_vlan;
267
268 dev->needs_free_netdev = true;
269
270 netif_set_tso_max_size(dev, GSO_MAX_SIZE);
271}
272
273static struct net *netkit_get_link_net(const struct net_device *dev)
274{
275 struct netkit *nk = netkit_priv(dev);
276 struct net_device *peer = rtnl_dereference(nk->peer);
277
278 return peer ? dev_net(peer) : dev_net(dev);
279}
280
281static int netkit_check_policy(int policy, struct nlattr *tb,
282 struct netlink_ext_ack *extack)
283{
284 switch (policy) {
285 case NETKIT_PASS:
286 case NETKIT_DROP:
287 return 0;
288 default:
289 NL_SET_ERR_MSG_ATTR(extack, tb,
290 "Provided default xmit policy not supported");
291 return -EINVAL;
292 }
293}
294
295static int netkit_check_mode(int mode, struct nlattr *tb,
296 struct netlink_ext_ack *extack)
297{
298 switch (mode) {
299 case NETKIT_L2:
300 case NETKIT_L3:
301 return 0;
302 default:
303 NL_SET_ERR_MSG_ATTR(extack, tb,
304 "Provided device mode can only be L2 or L3");
305 return -EINVAL;
306 }
307}
308
309static int netkit_validate(struct nlattr *tb[], struct nlattr *data[],
310 struct netlink_ext_ack *extack)
311{
312 struct nlattr *attr = tb[IFLA_ADDRESS];
313
314 if (!attr)
315 return 0;
316 if (nla_len(attr) != ETH_ALEN)
317 return -EINVAL;
318 if (!is_valid_ether_addr(nla_data(attr)))
319 return -EADDRNOTAVAIL;
320 return 0;
321}
322
323static struct rtnl_link_ops netkit_link_ops;
324
325static int netkit_new_link(struct net *src_net, struct net_device *dev,
326 struct nlattr *tb[], struct nlattr *data[],
327 struct netlink_ext_ack *extack)
328{
329 struct nlattr *peer_tb[IFLA_MAX + 1], **tbp = tb, *attr;
330 enum netkit_action default_prim = NETKIT_PASS;
331 enum netkit_action default_peer = NETKIT_PASS;
332 enum netkit_mode mode = NETKIT_L3;
333 unsigned char ifname_assign_type;
334 struct ifinfomsg *ifmp = NULL;
335 struct net_device *peer;
336 char ifname[IFNAMSIZ];
337 struct netkit *nk;
338 struct net *net;
339 int err;
340
341 if (data) {
342 if (data[IFLA_NETKIT_MODE]) {
343 attr = data[IFLA_NETKIT_MODE];
344 mode = nla_get_u32(attr);
345 err = netkit_check_mode(mode, attr, extack);
346 if (err < 0)
347 return err;
348 }
349 if (data[IFLA_NETKIT_PEER_INFO]) {
350 attr = data[IFLA_NETKIT_PEER_INFO];
351 ifmp = nla_data(attr);
352 err = rtnl_nla_parse_ifinfomsg(peer_tb, attr, extack);
353 if (err < 0)
354 return err;
355 err = netkit_validate(peer_tb, NULL, extack);
356 if (err < 0)
357 return err;
358 tbp = peer_tb;
359 }
360 if (data[IFLA_NETKIT_POLICY]) {
361 attr = data[IFLA_NETKIT_POLICY];
362 default_prim = nla_get_u32(attr);
363 err = netkit_check_policy(default_prim, attr, extack);
364 if (err < 0)
365 return err;
366 }
367 if (data[IFLA_NETKIT_PEER_POLICY]) {
368 attr = data[IFLA_NETKIT_PEER_POLICY];
369 default_peer = nla_get_u32(attr);
370 err = netkit_check_policy(default_peer, attr, extack);
371 if (err < 0)
372 return err;
373 }
374 }
375
376 if (ifmp && tbp[IFLA_IFNAME]) {
377 nla_strscpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
378 ifname_assign_type = NET_NAME_USER;
379 } else {
380 strscpy(ifname, "nk%d", IFNAMSIZ);
381 ifname_assign_type = NET_NAME_ENUM;
382 }
383 if (mode != NETKIT_L2 &&
384 (tb[IFLA_ADDRESS] || tbp[IFLA_ADDRESS]))
385 return -EOPNOTSUPP;
386
387 net = rtnl_link_get_net(src_net, tbp);
388 if (IS_ERR(net))
389 return PTR_ERR(net);
390
391 peer = rtnl_create_link(net, ifname, ifname_assign_type,
392 &netkit_link_ops, tbp, extack);
393 if (IS_ERR(peer)) {
394 put_net(net);
395 return PTR_ERR(peer);
396 }
397
398 netif_inherit_tso_max(peer, dev);
399
400 if (mode == NETKIT_L2 && !(ifmp && tbp[IFLA_ADDRESS]))
401 eth_hw_addr_random(peer);
402 if (ifmp && dev->ifindex)
403 peer->ifindex = ifmp->ifi_index;
404
405 nk = netkit_priv(peer);
406 nk->primary = false;
407 nk->policy = default_peer;
408 nk->mode = mode;
409 bpf_mprog_bundle_init(&nk->bundle);
410
411 err = register_netdevice(peer);
412 put_net(net);
413 if (err < 0)
414 goto err_register_peer;
415 netif_carrier_off(peer);
416 if (mode == NETKIT_L2)
417 dev_change_flags(peer, peer->flags & ~IFF_NOARP, NULL);
418
419 err = rtnl_configure_link(peer, NULL, 0, NULL);
420 if (err < 0)
421 goto err_configure_peer;
422
423 if (mode == NETKIT_L2 && !tb[IFLA_ADDRESS])
424 eth_hw_addr_random(dev);
425 if (tb[IFLA_IFNAME])
426 nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
427 else
428 strscpy(dev->name, "nk%d", IFNAMSIZ);
429
430 nk = netkit_priv(dev);
431 nk->primary = true;
432 nk->policy = default_prim;
433 nk->mode = mode;
434 bpf_mprog_bundle_init(&nk->bundle);
435
436 err = register_netdevice(dev);
437 if (err < 0)
438 goto err_configure_peer;
439 netif_carrier_off(dev);
440 if (mode == NETKIT_L2)
441 dev_change_flags(dev, dev->flags & ~IFF_NOARP, NULL);
442
443 rcu_assign_pointer(netkit_priv(dev)->peer, peer);
444 rcu_assign_pointer(netkit_priv(peer)->peer, dev);
445 return 0;
446err_configure_peer:
447 unregister_netdevice(peer);
448 return err;
449err_register_peer:
450 free_netdev(peer);
451 return err;
452}
453
454static struct bpf_mprog_entry *netkit_entry_fetch(struct net_device *dev,
455 bool bundle_fallback)
456{
457 struct netkit *nk = netkit_priv(dev);
458 struct bpf_mprog_entry *entry;
459
460 ASSERT_RTNL();
461 entry = rcu_dereference_rtnl(nk->active);
462 if (entry)
463 return entry;
464 if (bundle_fallback)
465 return &nk->bundle.a;
466 return NULL;
467}
468
469static void netkit_entry_update(struct net_device *dev,
470 struct bpf_mprog_entry *entry)
471{
472 struct netkit *nk = netkit_priv(dev);
473
474 ASSERT_RTNL();
475 rcu_assign_pointer(nk->active, entry);
476}
477
478static void netkit_entry_sync(void)
479{
480 synchronize_rcu();
481}
482
483static struct net_device *netkit_dev_fetch(struct net *net, u32 ifindex, u32 which)
484{
485 struct net_device *dev;
486 struct netkit *nk;
487
488 ASSERT_RTNL();
489
490 switch (which) {
491 case BPF_NETKIT_PRIMARY:
492 case BPF_NETKIT_PEER:
493 break;
494 default:
495 return ERR_PTR(-EINVAL);
496 }
497
498 dev = __dev_get_by_index(net, ifindex);
499 if (!dev)
500 return ERR_PTR(-ENODEV);
501 if (dev->netdev_ops != &netkit_netdev_ops)
502 return ERR_PTR(-ENXIO);
503
504 nk = netkit_priv(dev);
505 if (!nk->primary)
506 return ERR_PTR(-EACCES);
507 if (which == BPF_NETKIT_PEER) {
508 dev = rcu_dereference_rtnl(nk->peer);
509 if (!dev)
510 return ERR_PTR(-ENODEV);
511 }
512 return dev;
513}
514
515int netkit_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)
516{
517 struct bpf_mprog_entry *entry, *entry_new;
518 struct bpf_prog *replace_prog = NULL;
519 struct net_device *dev;
520 int ret;
521
522 rtnl_lock();
523 dev = netkit_dev_fetch(current->nsproxy->net_ns, attr->target_ifindex,
524 attr->attach_type);
525 if (IS_ERR(dev)) {
526 ret = PTR_ERR(dev);
527 goto out;
528 }
529 entry = netkit_entry_fetch(dev, true);
530 if (attr->attach_flags & BPF_F_REPLACE) {
531 replace_prog = bpf_prog_get_type(attr->replace_bpf_fd,
532 prog->type);
533 if (IS_ERR(replace_prog)) {
534 ret = PTR_ERR(replace_prog);
535 replace_prog = NULL;
536 goto out;
537 }
538 }
539 ret = bpf_mprog_attach(entry, &entry_new, prog, NULL, replace_prog,
540 attr->attach_flags, attr->relative_fd,
541 attr->expected_revision);
542 if (!ret) {
543 if (entry != entry_new) {
544 netkit_entry_update(dev, entry_new);
545 netkit_entry_sync();
546 }
547 bpf_mprog_commit(entry);
548 }
549out:
550 if (replace_prog)
551 bpf_prog_put(replace_prog);
552 rtnl_unlock();
553 return ret;
554}
555
556int netkit_prog_detach(const union bpf_attr *attr, struct bpf_prog *prog)
557{
558 struct bpf_mprog_entry *entry, *entry_new;
559 struct net_device *dev;
560 int ret;
561
562 rtnl_lock();
563 dev = netkit_dev_fetch(current->nsproxy->net_ns, attr->target_ifindex,
564 attr->attach_type);
565 if (IS_ERR(dev)) {
566 ret = PTR_ERR(dev);
567 goto out;
568 }
569 entry = netkit_entry_fetch(dev, false);
570 if (!entry) {
571 ret = -ENOENT;
572 goto out;
573 }
574 ret = bpf_mprog_detach(entry, &entry_new, prog, NULL, attr->attach_flags,
575 attr->relative_fd, attr->expected_revision);
576 if (!ret) {
577 if (!bpf_mprog_total(entry_new))
578 entry_new = NULL;
579 netkit_entry_update(dev, entry_new);
580 netkit_entry_sync();
581 bpf_mprog_commit(entry);
582 }
583out:
584 rtnl_unlock();
585 return ret;
586}
587
588int netkit_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr)
589{
590 struct net_device *dev;
591 int ret;
592
593 rtnl_lock();
594 dev = netkit_dev_fetch(current->nsproxy->net_ns,
595 attr->query.target_ifindex,
596 attr->query.attach_type);
597 if (IS_ERR(dev)) {
598 ret = PTR_ERR(dev);
599 goto out;
600 }
601 ret = bpf_mprog_query(attr, uattr, netkit_entry_fetch(dev, false));
602out:
603 rtnl_unlock();
604 return ret;
605}
606
607static struct netkit_link *netkit_link(const struct bpf_link *link)
608{
609 return container_of(link, struct netkit_link, link);
610}
611
612static int netkit_link_prog_attach(struct bpf_link *link, u32 flags,
613 u32 id_or_fd, u64 revision)
614{
615 struct netkit_link *nkl = netkit_link(link);
616 struct bpf_mprog_entry *entry, *entry_new;
617 struct net_device *dev = nkl->dev;
618 int ret;
619
620 ASSERT_RTNL();
621 entry = netkit_entry_fetch(dev, true);
622 ret = bpf_mprog_attach(entry, &entry_new, link->prog, link, NULL, flags,
623 id_or_fd, revision);
624 if (!ret) {
625 if (entry != entry_new) {
626 netkit_entry_update(dev, entry_new);
627 netkit_entry_sync();
628 }
629 bpf_mprog_commit(entry);
630 }
631 return ret;
632}
633
634static void netkit_link_release(struct bpf_link *link)
635{
636 struct netkit_link *nkl = netkit_link(link);
637 struct bpf_mprog_entry *entry, *entry_new;
638 struct net_device *dev;
639 int ret = 0;
640
641 rtnl_lock();
642 dev = nkl->dev;
643 if (!dev)
644 goto out;
645 entry = netkit_entry_fetch(dev, false);
646 if (!entry) {
647 ret = -ENOENT;
648 goto out;
649 }
650 ret = bpf_mprog_detach(entry, &entry_new, link->prog, link, 0, 0, 0);
651 if (!ret) {
652 if (!bpf_mprog_total(entry_new))
653 entry_new = NULL;
654 netkit_entry_update(dev, entry_new);
655 netkit_entry_sync();
656 bpf_mprog_commit(entry);
657 nkl->dev = NULL;
658 }
659out:
660 WARN_ON_ONCE(ret);
661 rtnl_unlock();
662}
663
664static int netkit_link_update(struct bpf_link *link, struct bpf_prog *nprog,
665 struct bpf_prog *oprog)
666{
667 struct netkit_link *nkl = netkit_link(link);
668 struct bpf_mprog_entry *entry, *entry_new;
669 struct net_device *dev;
670 int ret = 0;
671
672 rtnl_lock();
673 dev = nkl->dev;
674 if (!dev) {
675 ret = -ENOLINK;
676 goto out;
677 }
678 if (oprog && link->prog != oprog) {
679 ret = -EPERM;
680 goto out;
681 }
682 oprog = link->prog;
683 if (oprog == nprog) {
684 bpf_prog_put(nprog);
685 goto out;
686 }
687 entry = netkit_entry_fetch(dev, false);
688 if (!entry) {
689 ret = -ENOENT;
690 goto out;
691 }
692 ret = bpf_mprog_attach(entry, &entry_new, nprog, link, oprog,
693 BPF_F_REPLACE | BPF_F_ID,
694 link->prog->aux->id, 0);
695 if (!ret) {
696 WARN_ON_ONCE(entry != entry_new);
697 oprog = xchg(&link->prog, nprog);
698 bpf_prog_put(oprog);
699 bpf_mprog_commit(entry);
700 }
701out:
702 rtnl_unlock();
703 return ret;
704}
705
706static void netkit_link_dealloc(struct bpf_link *link)
707{
708 kfree(netkit_link(link));
709}
710
711static void netkit_link_fdinfo(const struct bpf_link *link, struct seq_file *seq)
712{
713 const struct netkit_link *nkl = netkit_link(link);
714 u32 ifindex = 0;
715
716 rtnl_lock();
717 if (nkl->dev)
718 ifindex = nkl->dev->ifindex;
719 rtnl_unlock();
720
721 seq_printf(seq, "ifindex:\t%u\n", ifindex);
722 seq_printf(seq, "attach_type:\t%u (%s)\n",
723 nkl->location,
724 nkl->location == BPF_NETKIT_PRIMARY ? "primary" : "peer");
725}
726
727static int netkit_link_fill_info(const struct bpf_link *link,
728 struct bpf_link_info *info)
729{
730 const struct netkit_link *nkl = netkit_link(link);
731 u32 ifindex = 0;
732
733 rtnl_lock();
734 if (nkl->dev)
735 ifindex = nkl->dev->ifindex;
736 rtnl_unlock();
737
738 info->netkit.ifindex = ifindex;
739 info->netkit.attach_type = nkl->location;
740 return 0;
741}
742
743static int netkit_link_detach(struct bpf_link *link)
744{
745 netkit_link_release(link);
746 return 0;
747}
748
749static const struct bpf_link_ops netkit_link_lops = {
750 .release = netkit_link_release,
751 .detach = netkit_link_detach,
752 .dealloc = netkit_link_dealloc,
753 .update_prog = netkit_link_update,
754 .show_fdinfo = netkit_link_fdinfo,
755 .fill_link_info = netkit_link_fill_info,
756};
757
758static int netkit_link_init(struct netkit_link *nkl,
759 struct bpf_link_primer *link_primer,
760 const union bpf_attr *attr,
761 struct net_device *dev,
762 struct bpf_prog *prog)
763{
764 bpf_link_init(&nkl->link, BPF_LINK_TYPE_NETKIT,
765 &netkit_link_lops, prog);
766 nkl->location = attr->link_create.attach_type;
767 nkl->dev = dev;
768 return bpf_link_prime(&nkl->link, link_primer);
769}
770
771int netkit_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
772{
773 struct bpf_link_primer link_primer;
774 struct netkit_link *nkl;
775 struct net_device *dev;
776 int ret;
777
778 rtnl_lock();
779 dev = netkit_dev_fetch(current->nsproxy->net_ns,
780 attr->link_create.target_ifindex,
781 attr->link_create.attach_type);
782 if (IS_ERR(dev)) {
783 ret = PTR_ERR(dev);
784 goto out;
785 }
786 nkl = kzalloc(sizeof(*nkl), GFP_KERNEL_ACCOUNT);
787 if (!nkl) {
788 ret = -ENOMEM;
789 goto out;
790 }
791 ret = netkit_link_init(nkl, &link_primer, attr, dev, prog);
792 if (ret) {
793 kfree(nkl);
794 goto out;
795 }
796 ret = netkit_link_prog_attach(&nkl->link,
797 attr->link_create.flags,
798 attr->link_create.netkit.relative_fd,
799 attr->link_create.netkit.expected_revision);
800 if (ret) {
801 nkl->dev = NULL;
802 bpf_link_cleanup(&link_primer);
803 goto out;
804 }
805 ret = bpf_link_settle(&link_primer);
806out:
807 rtnl_unlock();
808 return ret;
809}
810
811static void netkit_release_all(struct net_device *dev)
812{
813 struct bpf_mprog_entry *entry;
814 struct bpf_tuple tuple = {};
815 struct bpf_mprog_fp *fp;
816 struct bpf_mprog_cp *cp;
817
818 entry = netkit_entry_fetch(dev, false);
819 if (!entry)
820 return;
821 netkit_entry_update(dev, NULL);
822 netkit_entry_sync();
823 bpf_mprog_foreach_tuple(entry, fp, cp, tuple) {
824 if (tuple.link)
825 netkit_link(tuple.link)->dev = NULL;
826 else
827 bpf_prog_put(tuple.prog);
828 }
829}
830
831static void netkit_uninit(struct net_device *dev)
832{
833 netkit_release_all(dev);
834}
835
836static void netkit_del_link(struct net_device *dev, struct list_head *head)
837{
838 struct netkit *nk = netkit_priv(dev);
839 struct net_device *peer = rtnl_dereference(nk->peer);
840
841 RCU_INIT_POINTER(nk->peer, NULL);
842 unregister_netdevice_queue(dev, head);
843 if (peer) {
844 nk = netkit_priv(peer);
845 RCU_INIT_POINTER(nk->peer, NULL);
846 unregister_netdevice_queue(peer, head);
847 }
848}
849
850static int netkit_change_link(struct net_device *dev, struct nlattr *tb[],
851 struct nlattr *data[],
852 struct netlink_ext_ack *extack)
853{
854 struct netkit *nk = netkit_priv(dev);
855 struct net_device *peer = rtnl_dereference(nk->peer);
856 enum netkit_action policy;
857 struct nlattr *attr;
858 int err;
859
860 if (!nk->primary) {
861 NL_SET_ERR_MSG(extack,
862 "netkit link settings can be changed only through the primary device");
863 return -EACCES;
864 }
865
866 if (data[IFLA_NETKIT_MODE]) {
867 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_MODE],
868 "netkit link operating mode cannot be changed after device creation");
869 return -EACCES;
870 }
871
872 if (data[IFLA_NETKIT_PEER_INFO]) {
873 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_PEER_INFO],
874 "netkit peer info cannot be changed after device creation");
875 return -EINVAL;
876 }
877
878 if (data[IFLA_NETKIT_POLICY]) {
879 attr = data[IFLA_NETKIT_POLICY];
880 policy = nla_get_u32(attr);
881 err = netkit_check_policy(policy, attr, extack);
882 if (err)
883 return err;
884 WRITE_ONCE(nk->policy, policy);
885 }
886
887 if (data[IFLA_NETKIT_PEER_POLICY]) {
888 err = -EOPNOTSUPP;
889 attr = data[IFLA_NETKIT_PEER_POLICY];
890 policy = nla_get_u32(attr);
891 if (peer)
892 err = netkit_check_policy(policy, attr, extack);
893 if (err)
894 return err;
895 nk = netkit_priv(peer);
896 WRITE_ONCE(nk->policy, policy);
897 }
898
899 return 0;
900}
901
902static size_t netkit_get_size(const struct net_device *dev)
903{
904 return nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_POLICY */
905 nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_PEER_POLICY */
906 nla_total_size(sizeof(u8)) + /* IFLA_NETKIT_PRIMARY */
907 nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_MODE */
908 0;
909}
910
911static int netkit_fill_info(struct sk_buff *skb, const struct net_device *dev)
912{
913 struct netkit *nk = netkit_priv(dev);
914 struct net_device *peer = rtnl_dereference(nk->peer);
915
916 if (nla_put_u8(skb, IFLA_NETKIT_PRIMARY, nk->primary))
917 return -EMSGSIZE;
918 if (nla_put_u32(skb, IFLA_NETKIT_POLICY, nk->policy))
919 return -EMSGSIZE;
920 if (nla_put_u32(skb, IFLA_NETKIT_MODE, nk->mode))
921 return -EMSGSIZE;
922
923 if (peer) {
924 nk = netkit_priv(peer);
925 if (nla_put_u32(skb, IFLA_NETKIT_PEER_POLICY, nk->policy))
926 return -EMSGSIZE;
927 }
928
929 return 0;
930}
931
932static const struct nla_policy netkit_policy[IFLA_NETKIT_MAX + 1] = {
933 [IFLA_NETKIT_PEER_INFO] = { .len = sizeof(struct ifinfomsg) },
934 [IFLA_NETKIT_POLICY] = { .type = NLA_U32 },
935 [IFLA_NETKIT_MODE] = { .type = NLA_U32 },
936 [IFLA_NETKIT_PEER_POLICY] = { .type = NLA_U32 },
937 [IFLA_NETKIT_PRIMARY] = { .type = NLA_REJECT,
938 .reject_message = "Primary attribute is read-only" },
939};
940
941static struct rtnl_link_ops netkit_link_ops = {
942 .kind = DRV_NAME,
943 .priv_size = sizeof(struct netkit),
944 .setup = netkit_setup,
945 .newlink = netkit_new_link,
946 .dellink = netkit_del_link,
947 .changelink = netkit_change_link,
948 .get_link_net = netkit_get_link_net,
949 .get_size = netkit_get_size,
950 .fill_info = netkit_fill_info,
951 .policy = netkit_policy,
952 .validate = netkit_validate,
953 .maxtype = IFLA_NETKIT_MAX,
954};
955
956static __init int netkit_init(void)
957{
958 BUILD_BUG_ON((int)NETKIT_NEXT != (int)TCX_NEXT ||
959 (int)NETKIT_PASS != (int)TCX_PASS ||
960 (int)NETKIT_DROP != (int)TCX_DROP ||
961 (int)NETKIT_REDIRECT != (int)TCX_REDIRECT);
962
963 return rtnl_link_register(&netkit_link_ops);
964}
965
966static __exit void netkit_exit(void)
967{
968 rtnl_link_unregister(&netkit_link_ops);
969}
970
971module_init(netkit_init);
972module_exit(netkit_exit);
973
974MODULE_DESCRIPTION("BPF-programmable network device");
975MODULE_AUTHOR("Daniel Borkmann <daniel@iogearbox.net>");
976MODULE_AUTHOR("Nikolay Aleksandrov <razor@blackwall.org>");
977MODULE_LICENSE("GPL");
978MODULE_ALIAS_RTNL_LINK(DRV_NAME);