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, ctx: 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, skip: true);
58}
59
60static struct netkit *netkit_priv(const struct net_device *dev)
61{
62 return netdev_priv(dev);
63}
64
65static netdev_tx_t netkit_xmit(struct sk_buff *skb, struct net_device *dev)
66{
67 struct netkit *nk = netkit_priv(dev);
68 enum netkit_action ret = READ_ONCE(nk->policy);
69 netdev_tx_t ret_dev = NET_XMIT_SUCCESS;
70 const struct bpf_mprog_entry *entry;
71 struct net_device *peer;
72 int len = skb->len;
73
74 rcu_read_lock();
75 peer = rcu_dereference(nk->peer);
76 if (unlikely(!peer || !(peer->flags & IFF_UP) ||
77 !pskb_may_pull(skb, ETH_HLEN) ||
78 skb_orphan_frags(skb, GFP_ATOMIC)))
79 goto drop;
80 netkit_prep_forward(skb, xnet: !net_eq(net1: dev_net(dev), net2: dev_net(dev: peer)));
81 skb->dev = peer;
82 entry = rcu_dereference(nk->active);
83 if (entry)
84 ret = netkit_run(entry, skb, ret);
85 switch (ret) {
86 case NETKIT_NEXT:
87 case NETKIT_PASS:
88 skb->protocol = eth_type_trans(skb, dev: skb->dev);
89 skb_postpull_rcsum(skb, start: eth_hdr(skb), ETH_HLEN);
90 if (likely(__netif_rx(skb) == NET_RX_SUCCESS)) {
91 dev_sw_netstats_tx_add(dev, packets: 1, len);
92 dev_sw_netstats_rx_add(dev: peer, len);
93 } else {
94 goto drop_stats;
95 }
96 break;
97 case NETKIT_REDIRECT:
98 dev_sw_netstats_tx_add(dev, packets: 1, len);
99 skb_do_redirect(skb);
100 break;
101 case NETKIT_DROP:
102 default:
103drop:
104 kfree_skb(skb);
105drop_stats:
106 dev_core_stats_tx_dropped_inc(dev);
107 ret_dev = NET_XMIT_DROP;
108 break;
109 }
110 rcu_read_unlock();
111 return ret_dev;
112}
113
114static int netkit_open(struct net_device *dev)
115{
116 struct netkit *nk = netkit_priv(dev);
117 struct net_device *peer = rtnl_dereference(nk->peer);
118
119 if (!peer)
120 return -ENOTCONN;
121 if (peer->flags & IFF_UP) {
122 netif_carrier_on(dev);
123 netif_carrier_on(dev: peer);
124 }
125 return 0;
126}
127
128static int netkit_close(struct net_device *dev)
129{
130 struct netkit *nk = netkit_priv(dev);
131 struct net_device *peer = rtnl_dereference(nk->peer);
132
133 netif_carrier_off(dev);
134 if (peer)
135 netif_carrier_off(dev: peer);
136 return 0;
137}
138
139static int netkit_get_iflink(const struct net_device *dev)
140{
141 struct netkit *nk = netkit_priv(dev);
142 struct net_device *peer;
143 int iflink = 0;
144
145 rcu_read_lock();
146 peer = rcu_dereference(nk->peer);
147 if (peer)
148 iflink = READ_ONCE(peer->ifindex);
149 rcu_read_unlock();
150 return iflink;
151}
152
153static void netkit_set_multicast(struct net_device *dev)
154{
155 /* Nothing to do, we receive whatever gets pushed to us! */
156}
157
158static void netkit_set_headroom(struct net_device *dev, int headroom)
159{
160 struct netkit *nk = netkit_priv(dev), *nk2;
161 struct net_device *peer;
162
163 if (headroom < 0)
164 headroom = NET_SKB_PAD;
165
166 rcu_read_lock();
167 peer = rcu_dereference(nk->peer);
168 if (unlikely(!peer))
169 goto out;
170
171 nk2 = netkit_priv(dev: peer);
172 nk->headroom = headroom;
173 headroom = max(nk->headroom, nk2->headroom);
174
175 peer->needed_headroom = headroom;
176 dev->needed_headroom = headroom;
177out:
178 rcu_read_unlock();
179}
180
181INDIRECT_CALLABLE_SCOPE struct net_device *netkit_peer_dev(struct net_device *dev)
182{
183 return rcu_dereference(netkit_priv(dev)->peer);
184}
185
186static void netkit_get_stats(struct net_device *dev,
187 struct rtnl_link_stats64 *stats)
188{
189 dev_fetch_sw_netstats(s: stats, netstats: dev->tstats);
190 stats->tx_dropped = DEV_STATS_READ(dev, tx_dropped);
191}
192
193static void netkit_uninit(struct net_device *dev);
194
195static const struct net_device_ops netkit_netdev_ops = {
196 .ndo_open = netkit_open,
197 .ndo_stop = netkit_close,
198 .ndo_start_xmit = netkit_xmit,
199 .ndo_set_rx_mode = netkit_set_multicast,
200 .ndo_set_rx_headroom = netkit_set_headroom,
201 .ndo_get_iflink = netkit_get_iflink,
202 .ndo_get_peer_dev = netkit_peer_dev,
203 .ndo_get_stats64 = netkit_get_stats,
204 .ndo_uninit = netkit_uninit,
205 .ndo_features_check = passthru_features_check,
206};
207
208static void netkit_get_drvinfo(struct net_device *dev,
209 struct ethtool_drvinfo *info)
210{
211 strscpy(info->driver, DRV_NAME, sizeof(info->driver));
212}
213
214static const struct ethtool_ops netkit_ethtool_ops = {
215 .get_drvinfo = netkit_get_drvinfo,
216};
217
218static void netkit_setup(struct net_device *dev)
219{
220 static const netdev_features_t netkit_features_hw_vlan =
221 NETIF_F_HW_VLAN_CTAG_TX |
222 NETIF_F_HW_VLAN_CTAG_RX |
223 NETIF_F_HW_VLAN_STAG_TX |
224 NETIF_F_HW_VLAN_STAG_RX;
225 static const netdev_features_t netkit_features =
226 netkit_features_hw_vlan |
227 NETIF_F_SG |
228 NETIF_F_FRAGLIST |
229 NETIF_F_HW_CSUM |
230 NETIF_F_RXCSUM |
231 NETIF_F_SCTP_CRC |
232 NETIF_F_HIGHDMA |
233 NETIF_F_GSO_SOFTWARE |
234 NETIF_F_GSO_ENCAP_ALL;
235
236 ether_setup(dev);
237 dev->max_mtu = ETH_MAX_MTU;
238 dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
239
240 dev->flags |= IFF_NOARP;
241 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
242 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
243 dev->priv_flags |= IFF_PHONY_HEADROOM;
244 dev->priv_flags |= IFF_NO_QUEUE;
245
246 dev->ethtool_ops = &netkit_ethtool_ops;
247 dev->netdev_ops = &netkit_netdev_ops;
248
249 dev->features |= netkit_features | NETIF_F_LLTX;
250 dev->hw_features = netkit_features;
251 dev->hw_enc_features = netkit_features;
252 dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
253 dev->vlan_features = dev->features & ~netkit_features_hw_vlan;
254
255 dev->needs_free_netdev = true;
256
257 netif_set_tso_max_size(dev, GSO_MAX_SIZE);
258}
259
260static struct net *netkit_get_link_net(const struct net_device *dev)
261{
262 struct netkit *nk = netkit_priv(dev);
263 struct net_device *peer = rtnl_dereference(nk->peer);
264
265 return peer ? dev_net(dev: peer) : dev_net(dev);
266}
267
268static int netkit_check_policy(int policy, struct nlattr *tb,
269 struct netlink_ext_ack *extack)
270{
271 switch (policy) {
272 case NETKIT_PASS:
273 case NETKIT_DROP:
274 return 0;
275 default:
276 NL_SET_ERR_MSG_ATTR(extack, tb,
277 "Provided default xmit policy not supported");
278 return -EINVAL;
279 }
280}
281
282static int netkit_check_mode(int mode, struct nlattr *tb,
283 struct netlink_ext_ack *extack)
284{
285 switch (mode) {
286 case NETKIT_L2:
287 case NETKIT_L3:
288 return 0;
289 default:
290 NL_SET_ERR_MSG_ATTR(extack, tb,
291 "Provided device mode can only be L2 or L3");
292 return -EINVAL;
293 }
294}
295
296static int netkit_validate(struct nlattr *tb[], struct nlattr *data[],
297 struct netlink_ext_ack *extack)
298{
299 struct nlattr *attr = tb[IFLA_ADDRESS];
300
301 if (!attr)
302 return 0;
303 NL_SET_ERR_MSG_ATTR(extack, attr,
304 "Setting Ethernet address is not supported");
305 return -EOPNOTSUPP;
306}
307
308static struct rtnl_link_ops netkit_link_ops;
309
310static int netkit_new_link(struct net *src_net, struct net_device *dev,
311 struct nlattr *tb[], struct nlattr *data[],
312 struct netlink_ext_ack *extack)
313{
314 struct nlattr *peer_tb[IFLA_MAX + 1], **tbp = tb, *attr;
315 enum netkit_action default_prim = NETKIT_PASS;
316 enum netkit_action default_peer = NETKIT_PASS;
317 enum netkit_mode mode = NETKIT_L3;
318 unsigned char ifname_assign_type;
319 struct ifinfomsg *ifmp = NULL;
320 struct net_device *peer;
321 char ifname[IFNAMSIZ];
322 struct netkit *nk;
323 struct net *net;
324 int err;
325
326 if (data) {
327 if (data[IFLA_NETKIT_MODE]) {
328 attr = data[IFLA_NETKIT_MODE];
329 mode = nla_get_u32(nla: attr);
330 err = netkit_check_mode(mode, tb: attr, extack);
331 if (err < 0)
332 return err;
333 }
334 if (data[IFLA_NETKIT_PEER_INFO]) {
335 attr = data[IFLA_NETKIT_PEER_INFO];
336 ifmp = nla_data(nla: attr);
337 err = rtnl_nla_parse_ifinfomsg(tb: peer_tb, nla_peer: attr, exterr: extack);
338 if (err < 0)
339 return err;
340 err = netkit_validate(tb: peer_tb, NULL, extack);
341 if (err < 0)
342 return err;
343 tbp = peer_tb;
344 }
345 if (data[IFLA_NETKIT_POLICY]) {
346 attr = data[IFLA_NETKIT_POLICY];
347 default_prim = nla_get_u32(nla: attr);
348 err = netkit_check_policy(policy: default_prim, tb: attr, extack);
349 if (err < 0)
350 return err;
351 }
352 if (data[IFLA_NETKIT_PEER_POLICY]) {
353 attr = data[IFLA_NETKIT_PEER_POLICY];
354 default_peer = nla_get_u32(nla: attr);
355 err = netkit_check_policy(policy: default_peer, tb: attr, extack);
356 if (err < 0)
357 return err;
358 }
359 }
360
361 if (ifmp && tbp[IFLA_IFNAME]) {
362 nla_strscpy(dst: ifname, nla: tbp[IFLA_IFNAME], IFNAMSIZ);
363 ifname_assign_type = NET_NAME_USER;
364 } else {
365 strscpy(ifname, "nk%d", IFNAMSIZ);
366 ifname_assign_type = NET_NAME_ENUM;
367 }
368
369 net = rtnl_link_get_net(src_net, tb: tbp);
370 if (IS_ERR(ptr: net))
371 return PTR_ERR(ptr: net);
372
373 peer = rtnl_create_link(net, ifname, name_assign_type: ifname_assign_type,
374 ops: &netkit_link_ops, tb: tbp, extack);
375 if (IS_ERR(ptr: peer)) {
376 put_net(net);
377 return PTR_ERR(ptr: peer);
378 }
379
380 netif_inherit_tso_max(to: peer, from: dev);
381
382 if (mode == NETKIT_L2)
383 eth_hw_addr_random(dev: peer);
384 if (ifmp && dev->ifindex)
385 peer->ifindex = ifmp->ifi_index;
386
387 nk = netkit_priv(dev: peer);
388 nk->primary = false;
389 nk->policy = default_peer;
390 nk->mode = mode;
391 bpf_mprog_bundle_init(bundle: &nk->bundle);
392
393 err = register_netdevice(dev: peer);
394 put_net(net);
395 if (err < 0)
396 goto err_register_peer;
397 netif_carrier_off(dev: peer);
398 if (mode == NETKIT_L2)
399 dev_change_flags(dev: peer, flags: peer->flags & ~IFF_NOARP, NULL);
400
401 err = rtnl_configure_link(dev: peer, NULL, portid: 0, NULL);
402 if (err < 0)
403 goto err_configure_peer;
404
405 if (mode == NETKIT_L2)
406 eth_hw_addr_random(dev);
407 if (tb[IFLA_IFNAME])
408 nla_strscpy(dst: dev->name, nla: tb[IFLA_IFNAME], IFNAMSIZ);
409 else
410 strscpy(dev->name, "nk%d", IFNAMSIZ);
411
412 nk = netkit_priv(dev);
413 nk->primary = true;
414 nk->policy = default_prim;
415 nk->mode = mode;
416 bpf_mprog_bundle_init(bundle: &nk->bundle);
417
418 err = register_netdevice(dev);
419 if (err < 0)
420 goto err_configure_peer;
421 netif_carrier_off(dev);
422 if (mode == NETKIT_L2)
423 dev_change_flags(dev, flags: dev->flags & ~IFF_NOARP, NULL);
424
425 rcu_assign_pointer(netkit_priv(dev)->peer, peer);
426 rcu_assign_pointer(netkit_priv(peer)->peer, dev);
427 return 0;
428err_configure_peer:
429 unregister_netdevice(dev: peer);
430 return err;
431err_register_peer:
432 free_netdev(dev: peer);
433 return err;
434}
435
436static struct bpf_mprog_entry *netkit_entry_fetch(struct net_device *dev,
437 bool bundle_fallback)
438{
439 struct netkit *nk = netkit_priv(dev);
440 struct bpf_mprog_entry *entry;
441
442 ASSERT_RTNL();
443 entry = rcu_dereference_rtnl(nk->active);
444 if (entry)
445 return entry;
446 if (bundle_fallback)
447 return &nk->bundle.a;
448 return NULL;
449}
450
451static void netkit_entry_update(struct net_device *dev,
452 struct bpf_mprog_entry *entry)
453{
454 struct netkit *nk = netkit_priv(dev);
455
456 ASSERT_RTNL();
457 rcu_assign_pointer(nk->active, entry);
458}
459
460static void netkit_entry_sync(void)
461{
462 synchronize_rcu();
463}
464
465static struct net_device *netkit_dev_fetch(struct net *net, u32 ifindex, u32 which)
466{
467 struct net_device *dev;
468 struct netkit *nk;
469
470 ASSERT_RTNL();
471
472 switch (which) {
473 case BPF_NETKIT_PRIMARY:
474 case BPF_NETKIT_PEER:
475 break;
476 default:
477 return ERR_PTR(error: -EINVAL);
478 }
479
480 dev = __dev_get_by_index(net, ifindex);
481 if (!dev)
482 return ERR_PTR(error: -ENODEV);
483 if (dev->netdev_ops != &netkit_netdev_ops)
484 return ERR_PTR(error: -ENXIO);
485
486 nk = netkit_priv(dev);
487 if (!nk->primary)
488 return ERR_PTR(error: -EACCES);
489 if (which == BPF_NETKIT_PEER) {
490 dev = rcu_dereference_rtnl(nk->peer);
491 if (!dev)
492 return ERR_PTR(error: -ENODEV);
493 }
494 return dev;
495}
496
497int netkit_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog)
498{
499 struct bpf_mprog_entry *entry, *entry_new;
500 struct bpf_prog *replace_prog = NULL;
501 struct net_device *dev;
502 int ret;
503
504 rtnl_lock();
505 dev = netkit_dev_fetch(current->nsproxy->net_ns, ifindex: attr->target_ifindex,
506 which: attr->attach_type);
507 if (IS_ERR(ptr: dev)) {
508 ret = PTR_ERR(ptr: dev);
509 goto out;
510 }
511 entry = netkit_entry_fetch(dev, bundle_fallback: true);
512 if (attr->attach_flags & BPF_F_REPLACE) {
513 replace_prog = bpf_prog_get_type(ufd: attr->replace_bpf_fd,
514 type: prog->type);
515 if (IS_ERR(ptr: replace_prog)) {
516 ret = PTR_ERR(ptr: replace_prog);
517 replace_prog = NULL;
518 goto out;
519 }
520 }
521 ret = bpf_mprog_attach(entry, entry_new: &entry_new, prog_new: prog, NULL, prog_old: replace_prog,
522 flags: attr->attach_flags, id_or_fd: attr->relative_fd,
523 revision: attr->expected_revision);
524 if (!ret) {
525 if (entry != entry_new) {
526 netkit_entry_update(dev, entry: entry_new);
527 netkit_entry_sync();
528 }
529 bpf_mprog_commit(entry);
530 }
531out:
532 if (replace_prog)
533 bpf_prog_put(prog: replace_prog);
534 rtnl_unlock();
535 return ret;
536}
537
538int netkit_prog_detach(const union bpf_attr *attr, struct bpf_prog *prog)
539{
540 struct bpf_mprog_entry *entry, *entry_new;
541 struct net_device *dev;
542 int ret;
543
544 rtnl_lock();
545 dev = netkit_dev_fetch(current->nsproxy->net_ns, ifindex: attr->target_ifindex,
546 which: attr->attach_type);
547 if (IS_ERR(ptr: dev)) {
548 ret = PTR_ERR(ptr: dev);
549 goto out;
550 }
551 entry = netkit_entry_fetch(dev, bundle_fallback: false);
552 if (!entry) {
553 ret = -ENOENT;
554 goto out;
555 }
556 ret = bpf_mprog_detach(entry, entry_new: &entry_new, prog, NULL, flags: attr->attach_flags,
557 id_or_fd: attr->relative_fd, revision: attr->expected_revision);
558 if (!ret) {
559 if (!bpf_mprog_total(entry: entry_new))
560 entry_new = NULL;
561 netkit_entry_update(dev, entry: entry_new);
562 netkit_entry_sync();
563 bpf_mprog_commit(entry);
564 }
565out:
566 rtnl_unlock();
567 return ret;
568}
569
570int netkit_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr)
571{
572 struct net_device *dev;
573 int ret;
574
575 rtnl_lock();
576 dev = netkit_dev_fetch(current->nsproxy->net_ns,
577 ifindex: attr->query.target_ifindex,
578 which: attr->query.attach_type);
579 if (IS_ERR(ptr: dev)) {
580 ret = PTR_ERR(ptr: dev);
581 goto out;
582 }
583 ret = bpf_mprog_query(attr, uattr, entry: netkit_entry_fetch(dev, bundle_fallback: false));
584out:
585 rtnl_unlock();
586 return ret;
587}
588
589static struct netkit_link *netkit_link(const struct bpf_link *link)
590{
591 return container_of(link, struct netkit_link, link);
592}
593
594static int netkit_link_prog_attach(struct bpf_link *link, u32 flags,
595 u32 id_or_fd, u64 revision)
596{
597 struct netkit_link *nkl = netkit_link(link);
598 struct bpf_mprog_entry *entry, *entry_new;
599 struct net_device *dev = nkl->dev;
600 int ret;
601
602 ASSERT_RTNL();
603 entry = netkit_entry_fetch(dev, bundle_fallback: true);
604 ret = bpf_mprog_attach(entry, entry_new: &entry_new, prog_new: link->prog, link, NULL, flags,
605 id_or_fd, revision);
606 if (!ret) {
607 if (entry != entry_new) {
608 netkit_entry_update(dev, entry: entry_new);
609 netkit_entry_sync();
610 }
611 bpf_mprog_commit(entry);
612 }
613 return ret;
614}
615
616static void netkit_link_release(struct bpf_link *link)
617{
618 struct netkit_link *nkl = netkit_link(link);
619 struct bpf_mprog_entry *entry, *entry_new;
620 struct net_device *dev;
621 int ret = 0;
622
623 rtnl_lock();
624 dev = nkl->dev;
625 if (!dev)
626 goto out;
627 entry = netkit_entry_fetch(dev, bundle_fallback: false);
628 if (!entry) {
629 ret = -ENOENT;
630 goto out;
631 }
632 ret = bpf_mprog_detach(entry, entry_new: &entry_new, prog: link->prog, link, flags: 0, id_or_fd: 0, revision: 0);
633 if (!ret) {
634 if (!bpf_mprog_total(entry: entry_new))
635 entry_new = NULL;
636 netkit_entry_update(dev, entry: entry_new);
637 netkit_entry_sync();
638 bpf_mprog_commit(entry);
639 nkl->dev = NULL;
640 }
641out:
642 WARN_ON_ONCE(ret);
643 rtnl_unlock();
644}
645
646static int netkit_link_update(struct bpf_link *link, struct bpf_prog *nprog,
647 struct bpf_prog *oprog)
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 ret = -ENOLINK;
658 goto out;
659 }
660 if (oprog && link->prog != oprog) {
661 ret = -EPERM;
662 goto out;
663 }
664 oprog = link->prog;
665 if (oprog == nprog) {
666 bpf_prog_put(prog: nprog);
667 goto out;
668 }
669 entry = netkit_entry_fetch(dev, bundle_fallback: false);
670 if (!entry) {
671 ret = -ENOENT;
672 goto out;
673 }
674 ret = bpf_mprog_attach(entry, entry_new: &entry_new, prog_new: nprog, link, prog_old: oprog,
675 BPF_F_REPLACE | BPF_F_ID,
676 id_or_fd: link->prog->aux->id, revision: 0);
677 if (!ret) {
678 WARN_ON_ONCE(entry != entry_new);
679 oprog = xchg(&link->prog, nprog);
680 bpf_prog_put(prog: oprog);
681 bpf_mprog_commit(entry);
682 }
683out:
684 rtnl_unlock();
685 return ret;
686}
687
688static void netkit_link_dealloc(struct bpf_link *link)
689{
690 kfree(objp: netkit_link(link));
691}
692
693static void netkit_link_fdinfo(const struct bpf_link *link, struct seq_file *seq)
694{
695 const struct netkit_link *nkl = netkit_link(link);
696 u32 ifindex = 0;
697
698 rtnl_lock();
699 if (nkl->dev)
700 ifindex = nkl->dev->ifindex;
701 rtnl_unlock();
702
703 seq_printf(m: seq, fmt: "ifindex:\t%u\n", ifindex);
704 seq_printf(m: seq, fmt: "attach_type:\t%u (%s)\n",
705 nkl->location,
706 nkl->location == BPF_NETKIT_PRIMARY ? "primary" : "peer");
707}
708
709static int netkit_link_fill_info(const struct bpf_link *link,
710 struct bpf_link_info *info)
711{
712 const struct netkit_link *nkl = netkit_link(link);
713 u32 ifindex = 0;
714
715 rtnl_lock();
716 if (nkl->dev)
717 ifindex = nkl->dev->ifindex;
718 rtnl_unlock();
719
720 info->netkit.ifindex = ifindex;
721 info->netkit.attach_type = nkl->location;
722 return 0;
723}
724
725static int netkit_link_detach(struct bpf_link *link)
726{
727 netkit_link_release(link);
728 return 0;
729}
730
731static const struct bpf_link_ops netkit_link_lops = {
732 .release = netkit_link_release,
733 .detach = netkit_link_detach,
734 .dealloc = netkit_link_dealloc,
735 .update_prog = netkit_link_update,
736 .show_fdinfo = netkit_link_fdinfo,
737 .fill_link_info = netkit_link_fill_info,
738};
739
740static int netkit_link_init(struct netkit_link *nkl,
741 struct bpf_link_primer *link_primer,
742 const union bpf_attr *attr,
743 struct net_device *dev,
744 struct bpf_prog *prog)
745{
746 bpf_link_init(link: &nkl->link, type: BPF_LINK_TYPE_NETKIT,
747 ops: &netkit_link_lops, prog);
748 nkl->location = attr->link_create.attach_type;
749 nkl->dev = dev;
750 return bpf_link_prime(link: &nkl->link, primer: link_primer);
751}
752
753int netkit_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
754{
755 struct bpf_link_primer link_primer;
756 struct netkit_link *nkl;
757 struct net_device *dev;
758 int ret;
759
760 rtnl_lock();
761 dev = netkit_dev_fetch(current->nsproxy->net_ns,
762 ifindex: attr->link_create.target_ifindex,
763 which: attr->link_create.attach_type);
764 if (IS_ERR(ptr: dev)) {
765 ret = PTR_ERR(ptr: dev);
766 goto out;
767 }
768 nkl = kzalloc(size: sizeof(*nkl), GFP_KERNEL_ACCOUNT);
769 if (!nkl) {
770 ret = -ENOMEM;
771 goto out;
772 }
773 ret = netkit_link_init(nkl, link_primer: &link_primer, attr, dev, prog);
774 if (ret) {
775 kfree(objp: nkl);
776 goto out;
777 }
778 ret = netkit_link_prog_attach(link: &nkl->link,
779 flags: attr->link_create.flags,
780 id_or_fd: attr->link_create.netkit.relative_fd,
781 revision: attr->link_create.netkit.expected_revision);
782 if (ret) {
783 nkl->dev = NULL;
784 bpf_link_cleanup(primer: &link_primer);
785 goto out;
786 }
787 ret = bpf_link_settle(primer: &link_primer);
788out:
789 rtnl_unlock();
790 return ret;
791}
792
793static void netkit_release_all(struct net_device *dev)
794{
795 struct bpf_mprog_entry *entry;
796 struct bpf_tuple tuple = {};
797 struct bpf_mprog_fp *fp;
798 struct bpf_mprog_cp *cp;
799
800 entry = netkit_entry_fetch(dev, bundle_fallback: false);
801 if (!entry)
802 return;
803 netkit_entry_update(dev, NULL);
804 netkit_entry_sync();
805 bpf_mprog_foreach_tuple(entry, fp, cp, tuple) {
806 if (tuple.link)
807 netkit_link(link: tuple.link)->dev = NULL;
808 else
809 bpf_prog_put(prog: tuple.prog);
810 }
811}
812
813static void netkit_uninit(struct net_device *dev)
814{
815 netkit_release_all(dev);
816}
817
818static void netkit_del_link(struct net_device *dev, struct list_head *head)
819{
820 struct netkit *nk = netkit_priv(dev);
821 struct net_device *peer = rtnl_dereference(nk->peer);
822
823 RCU_INIT_POINTER(nk->peer, NULL);
824 unregister_netdevice_queue(dev, head);
825 if (peer) {
826 nk = netkit_priv(dev: peer);
827 RCU_INIT_POINTER(nk->peer, NULL);
828 unregister_netdevice_queue(dev: peer, head);
829 }
830}
831
832static int netkit_change_link(struct net_device *dev, struct nlattr *tb[],
833 struct nlattr *data[],
834 struct netlink_ext_ack *extack)
835{
836 struct netkit *nk = netkit_priv(dev);
837 struct net_device *peer = rtnl_dereference(nk->peer);
838 enum netkit_action policy;
839 struct nlattr *attr;
840 int err;
841
842 if (!nk->primary) {
843 NL_SET_ERR_MSG(extack,
844 "netkit link settings can be changed only through the primary device");
845 return -EACCES;
846 }
847
848 if (data[IFLA_NETKIT_MODE]) {
849 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_MODE],
850 "netkit link operating mode cannot be changed after device creation");
851 return -EACCES;
852 }
853
854 if (data[IFLA_NETKIT_PEER_INFO]) {
855 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_PEER_INFO],
856 "netkit peer info cannot be changed after device creation");
857 return -EINVAL;
858 }
859
860 if (data[IFLA_NETKIT_POLICY]) {
861 attr = data[IFLA_NETKIT_POLICY];
862 policy = nla_get_u32(nla: attr);
863 err = netkit_check_policy(policy, tb: attr, extack);
864 if (err)
865 return err;
866 WRITE_ONCE(nk->policy, policy);
867 }
868
869 if (data[IFLA_NETKIT_PEER_POLICY]) {
870 err = -EOPNOTSUPP;
871 attr = data[IFLA_NETKIT_PEER_POLICY];
872 policy = nla_get_u32(nla: attr);
873 if (peer)
874 err = netkit_check_policy(policy, tb: attr, extack);
875 if (err)
876 return err;
877 nk = netkit_priv(dev: peer);
878 WRITE_ONCE(nk->policy, policy);
879 }
880
881 return 0;
882}
883
884static size_t netkit_get_size(const struct net_device *dev)
885{
886 return nla_total_size(payload: sizeof(u32)) + /* IFLA_NETKIT_POLICY */
887 nla_total_size(payload: sizeof(u32)) + /* IFLA_NETKIT_PEER_POLICY */
888 nla_total_size(payload: sizeof(u8)) + /* IFLA_NETKIT_PRIMARY */
889 nla_total_size(payload: sizeof(u32)) + /* IFLA_NETKIT_MODE */
890 0;
891}
892
893static int netkit_fill_info(struct sk_buff *skb, const struct net_device *dev)
894{
895 struct netkit *nk = netkit_priv(dev);
896 struct net_device *peer = rtnl_dereference(nk->peer);
897
898 if (nla_put_u8(skb, attrtype: IFLA_NETKIT_PRIMARY, value: nk->primary))
899 return -EMSGSIZE;
900 if (nla_put_u32(skb, attrtype: IFLA_NETKIT_POLICY, value: nk->policy))
901 return -EMSGSIZE;
902 if (nla_put_u32(skb, attrtype: IFLA_NETKIT_MODE, value: nk->mode))
903 return -EMSGSIZE;
904
905 if (peer) {
906 nk = netkit_priv(dev: peer);
907 if (nla_put_u32(skb, attrtype: IFLA_NETKIT_PEER_POLICY, value: nk->policy))
908 return -EMSGSIZE;
909 }
910
911 return 0;
912}
913
914static const struct nla_policy netkit_policy[IFLA_NETKIT_MAX + 1] = {
915 [IFLA_NETKIT_PEER_INFO] = { .len = sizeof(struct ifinfomsg) },
916 [IFLA_NETKIT_POLICY] = { .type = NLA_U32 },
917 [IFLA_NETKIT_MODE] = { .type = NLA_U32 },
918 [IFLA_NETKIT_PEER_POLICY] = { .type = NLA_U32 },
919 [IFLA_NETKIT_PRIMARY] = { .type = NLA_REJECT,
920 .reject_message = "Primary attribute is read-only" },
921};
922
923static struct rtnl_link_ops netkit_link_ops = {
924 .kind = DRV_NAME,
925 .priv_size = sizeof(struct netkit),
926 .setup = netkit_setup,
927 .newlink = netkit_new_link,
928 .dellink = netkit_del_link,
929 .changelink = netkit_change_link,
930 .get_link_net = netkit_get_link_net,
931 .get_size = netkit_get_size,
932 .fill_info = netkit_fill_info,
933 .policy = netkit_policy,
934 .validate = netkit_validate,
935 .maxtype = IFLA_NETKIT_MAX,
936};
937
938static __init int netkit_init(void)
939{
940 BUILD_BUG_ON((int)NETKIT_NEXT != (int)TCX_NEXT ||
941 (int)NETKIT_PASS != (int)TCX_PASS ||
942 (int)NETKIT_DROP != (int)TCX_DROP ||
943 (int)NETKIT_REDIRECT != (int)TCX_REDIRECT);
944
945 return rtnl_link_register(ops: &netkit_link_ops);
946}
947
948static __exit void netkit_exit(void)
949{
950 rtnl_link_unregister(ops: &netkit_link_ops);
951}
952
953module_init(netkit_init);
954module_exit(netkit_exit);
955
956MODULE_DESCRIPTION("BPF-programmable network device");
957MODULE_AUTHOR("Daniel Borkmann <daniel@iogearbox.net>");
958MODULE_AUTHOR("Nikolay Aleksandrov <razor@blackwall.org>");
959MODULE_LICENSE("GPL");
960MODULE_ALIAS_RTNL_LINK(DRV_NAME);
961

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