Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
[platform/kernel/linux-rpi.git] / net / ipv6 / ip6_offload.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *      IPV6 GSO/GRO offload support
4  *      Linux INET6 implementation
5  */
6
7 #include <linux/kernel.h>
8 #include <linux/socket.h>
9 #include <linux/netdevice.h>
10 #include <linux/skbuff.h>
11 #include <linux/printk.h>
12
13 #include <net/protocol.h>
14 #include <net/ipv6.h>
15 #include <net/inet_common.h>
16 #include <net/tcp.h>
17 #include <net/udp.h>
18 #include <net/gro.h>
19
20 #include "ip6_offload.h"
21
22 /* All GRO functions are always builtin, except UDP over ipv6, which lays in
23  * ipv6 module, as it depends on UDPv6 lookup function, so we need special care
24  * when ipv6 is built as a module
25  */
26 #if IS_BUILTIN(CONFIG_IPV6)
27 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__)
28 #else
29 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_1(f, f2, __VA_ARGS__)
30 #endif
31
32 #define indirect_call_gro_receive_l4(f2, f1, cb, head, skb)     \
33 ({                                                              \
34         unlikely(gro_recursion_inc_test(skb)) ?                 \
35                 NAPI_GRO_CB(skb)->flush |= 1, NULL :            \
36                 INDIRECT_CALL_L4(cb, f2, f1, head, skb);        \
37 })
38
39 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
40 {
41         const struct net_offload *ops = NULL;
42
43         for (;;) {
44                 struct ipv6_opt_hdr *opth;
45                 int len;
46
47                 if (proto != NEXTHDR_HOP) {
48                         ops = rcu_dereference(inet6_offloads[proto]);
49
50                         if (unlikely(!ops))
51                                 break;
52
53                         if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
54                                 break;
55                 }
56
57                 if (unlikely(!pskb_may_pull(skb, 8)))
58                         break;
59
60                 opth = (void *)skb->data;
61                 len = ipv6_optlen(opth);
62
63                 if (unlikely(!pskb_may_pull(skb, len)))
64                         break;
65
66                 opth = (void *)skb->data;
67                 proto = opth->nexthdr;
68                 __skb_pull(skb, len);
69         }
70
71         return proto;
72 }
73
74 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
75         netdev_features_t features)
76 {
77         struct sk_buff *segs = ERR_PTR(-EINVAL);
78         struct ipv6hdr *ipv6h;
79         const struct net_offload *ops;
80         int proto;
81         struct frag_hdr *fptr;
82         unsigned int payload_len;
83         u8 *prevhdr;
84         int offset = 0;
85         bool encap, udpfrag;
86         int nhoff;
87         bool gso_partial;
88
89         skb_reset_network_header(skb);
90         nhoff = skb_network_header(skb) - skb_mac_header(skb);
91         if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
92                 goto out;
93
94         encap = SKB_GSO_CB(skb)->encap_level > 0;
95         if (encap)
96                 features &= skb->dev->hw_enc_features;
97         SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
98
99         ipv6h = ipv6_hdr(skb);
100         __skb_pull(skb, sizeof(*ipv6h));
101         segs = ERR_PTR(-EPROTONOSUPPORT);
102
103         proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
104
105         if (skb->encapsulation &&
106             skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
107                 udpfrag = proto == IPPROTO_UDP && encap &&
108                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
109         else
110                 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
111                           (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
112
113         ops = rcu_dereference(inet6_offloads[proto]);
114         if (likely(ops && ops->callbacks.gso_segment)) {
115                 skb_reset_transport_header(skb);
116                 segs = ops->callbacks.gso_segment(skb, features);
117         }
118
119         if (IS_ERR_OR_NULL(segs))
120                 goto out;
121
122         gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
123
124         for (skb = segs; skb; skb = skb->next) {
125                 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
126                 if (gso_partial && skb_is_gso(skb))
127                         payload_len = skb_shinfo(skb)->gso_size +
128                                       SKB_GSO_CB(skb)->data_offset +
129                                       skb->head - (unsigned char *)(ipv6h + 1);
130                 else
131                         payload_len = skb->len - nhoff - sizeof(*ipv6h);
132                 ipv6h->payload_len = htons(payload_len);
133                 skb->network_header = (u8 *)ipv6h - skb->head;
134                 skb_reset_mac_len(skb);
135
136                 if (udpfrag) {
137                         int err = ip6_find_1stfragopt(skb, &prevhdr);
138                         if (err < 0) {
139                                 kfree_skb_list(segs);
140                                 return ERR_PTR(err);
141                         }
142                         fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
143                         fptr->frag_off = htons(offset);
144                         if (skb->next)
145                                 fptr->frag_off |= htons(IP6_MF);
146                         offset += (ntohs(ipv6h->payload_len) -
147                                    sizeof(struct frag_hdr));
148                 }
149                 if (encap)
150                         skb_reset_inner_headers(skb);
151         }
152
153 out:
154         return segs;
155 }
156
157 /* Return the total length of all the extension hdrs, following the same
158  * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
159  */
160 static int ipv6_exthdrs_len(struct ipv6hdr *iph,
161                             const struct net_offload **opps)
162 {
163         struct ipv6_opt_hdr *opth = (void *)iph;
164         int len = 0, proto, optlen = sizeof(*iph);
165
166         proto = iph->nexthdr;
167         for (;;) {
168                 if (proto != NEXTHDR_HOP) {
169                         *opps = rcu_dereference(inet6_offloads[proto]);
170                         if (unlikely(!(*opps)))
171                                 break;
172                         if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
173                                 break;
174                 }
175                 opth = (void *)opth + optlen;
176                 optlen = ipv6_optlen(opth);
177                 len += optlen;
178                 proto = opth->nexthdr;
179         }
180         return len;
181 }
182
183 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
184                                                          struct sk_buff *skb)
185 {
186         const struct net_offload *ops;
187         struct sk_buff *pp = NULL;
188         struct sk_buff *p;
189         struct ipv6hdr *iph;
190         unsigned int nlen;
191         unsigned int hlen;
192         unsigned int off;
193         u16 flush = 1;
194         int proto;
195
196         off = skb_gro_offset(skb);
197         hlen = off + sizeof(*iph);
198         iph = skb_gro_header_fast(skb, off);
199         if (skb_gro_header_hard(skb, hlen)) {
200                 iph = skb_gro_header_slow(skb, hlen, off);
201                 if (unlikely(!iph))
202                         goto out;
203         }
204
205         skb_set_network_header(skb, off);
206         skb_gro_pull(skb, sizeof(*iph));
207         skb_set_transport_header(skb, skb_gro_offset(skb));
208
209         flush += ntohs(iph->payload_len) != skb_gro_len(skb);
210
211         rcu_read_lock();
212         proto = iph->nexthdr;
213         ops = rcu_dereference(inet6_offloads[proto]);
214         if (!ops || !ops->callbacks.gro_receive) {
215                 __pskb_pull(skb, skb_gro_offset(skb));
216                 skb_gro_frag0_invalidate(skb);
217                 proto = ipv6_gso_pull_exthdrs(skb, proto);
218                 skb_gro_pull(skb, -skb_transport_offset(skb));
219                 skb_reset_transport_header(skb);
220                 __skb_push(skb, skb_gro_offset(skb));
221
222                 ops = rcu_dereference(inet6_offloads[proto]);
223                 if (!ops || !ops->callbacks.gro_receive)
224                         goto out_unlock;
225
226                 iph = ipv6_hdr(skb);
227         }
228
229         NAPI_GRO_CB(skb)->proto = proto;
230
231         flush--;
232         nlen = skb_network_header_len(skb);
233
234         list_for_each_entry(p, head, list) {
235                 const struct ipv6hdr *iph2;
236                 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
237
238                 if (!NAPI_GRO_CB(p)->same_flow)
239                         continue;
240
241                 iph2 = (struct ipv6hdr *)(p->data + off);
242                 first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
243
244                 /* All fields must match except length and Traffic Class.
245                  * XXX skbs on the gro_list have all been parsed and pulled
246                  * already so we don't need to compare nlen
247                  * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
248                  * memcmp() alone below is sufficient, right?
249                  */
250                  if ((first_word & htonl(0xF00FFFFF)) ||
251                     !ipv6_addr_equal(&iph->saddr, &iph2->saddr) ||
252                     !ipv6_addr_equal(&iph->daddr, &iph2->daddr) ||
253                     *(u16 *)&iph->nexthdr != *(u16 *)&iph2->nexthdr) {
254 not_same_flow:
255                         NAPI_GRO_CB(p)->same_flow = 0;
256                         continue;
257                 }
258                 if (unlikely(nlen > sizeof(struct ipv6hdr))) {
259                         if (memcmp(iph + 1, iph2 + 1,
260                                    nlen - sizeof(struct ipv6hdr)))
261                                 goto not_same_flow;
262                 }
263                 /* flush if Traffic Class fields are different */
264                 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000));
265                 NAPI_GRO_CB(p)->flush |= flush;
266
267                 /* If the previous IP ID value was based on an atomic
268                  * datagram we can overwrite the value and ignore it.
269                  */
270                 if (NAPI_GRO_CB(skb)->is_atomic)
271                         NAPI_GRO_CB(p)->flush_id = 0;
272         }
273
274         NAPI_GRO_CB(skb)->is_atomic = true;
275         NAPI_GRO_CB(skb)->flush |= flush;
276
277         skb_gro_postpull_rcsum(skb, iph, nlen);
278
279         pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive,
280                                          ops->callbacks.gro_receive, head, skb);
281
282 out_unlock:
283         rcu_read_unlock();
284
285 out:
286         skb_gro_flush_final(skb, pp, flush);
287
288         return pp;
289 }
290
291 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
292                                               struct sk_buff *skb)
293 {
294         /* Common GRO receive for SIT and IP6IP6 */
295
296         if (NAPI_GRO_CB(skb)->encap_mark) {
297                 NAPI_GRO_CB(skb)->flush = 1;
298                 return NULL;
299         }
300
301         NAPI_GRO_CB(skb)->encap_mark = 1;
302
303         return ipv6_gro_receive(head, skb);
304 }
305
306 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
307                                           struct sk_buff *skb)
308 {
309         /* Common GRO receive for SIT and IP6IP6 */
310
311         if (NAPI_GRO_CB(skb)->encap_mark) {
312                 NAPI_GRO_CB(skb)->flush = 1;
313                 return NULL;
314         }
315
316         NAPI_GRO_CB(skb)->encap_mark = 1;
317
318         return inet_gro_receive(head, skb);
319 }
320
321 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
322 {
323         const struct net_offload *ops;
324         struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
325         int err = -ENOSYS;
326
327         if (skb->encapsulation) {
328                 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
329                 skb_set_inner_network_header(skb, nhoff);
330         }
331
332         iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
333
334         rcu_read_lock();
335
336         nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
337         if (WARN_ON(!ops || !ops->callbacks.gro_complete))
338                 goto out_unlock;
339
340         err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
341                                udp6_gro_complete, skb, nhoff);
342
343 out_unlock:
344         rcu_read_unlock();
345
346         return err;
347 }
348
349 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
350 {
351         skb->encapsulation = 1;
352         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
353         return ipv6_gro_complete(skb, nhoff);
354 }
355
356 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
357 {
358         skb->encapsulation = 1;
359         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
360         return ipv6_gro_complete(skb, nhoff);
361 }
362
363 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
364 {
365         skb->encapsulation = 1;
366         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
367         return inet_gro_complete(skb, nhoff);
368 }
369
370 static struct packet_offload ipv6_packet_offload __read_mostly = {
371         .type = cpu_to_be16(ETH_P_IPV6),
372         .callbacks = {
373                 .gso_segment = ipv6_gso_segment,
374                 .gro_receive = ipv6_gro_receive,
375                 .gro_complete = ipv6_gro_complete,
376         },
377 };
378
379 static struct sk_buff *sit_gso_segment(struct sk_buff *skb,
380                                        netdev_features_t features)
381 {
382         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
383                 return ERR_PTR(-EINVAL);
384
385         return ipv6_gso_segment(skb, features);
386 }
387
388 static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb,
389                                           netdev_features_t features)
390 {
391         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
392                 return ERR_PTR(-EINVAL);
393
394         return inet_gso_segment(skb, features);
395 }
396
397 static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb,
398                                           netdev_features_t features)
399 {
400         if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
401                 return ERR_PTR(-EINVAL);
402
403         return ipv6_gso_segment(skb, features);
404 }
405
406 static const struct net_offload sit_offload = {
407         .callbacks = {
408                 .gso_segment    = sit_gso_segment,
409                 .gro_receive    = sit_ip6ip6_gro_receive,
410                 .gro_complete   = sit_gro_complete,
411         },
412 };
413
414 static const struct net_offload ip4ip6_offload = {
415         .callbacks = {
416                 .gso_segment    = ip4ip6_gso_segment,
417                 .gro_receive    = ip4ip6_gro_receive,
418                 .gro_complete   = ip4ip6_gro_complete,
419         },
420 };
421
422 static const struct net_offload ip6ip6_offload = {
423         .callbacks = {
424                 .gso_segment    = ip6ip6_gso_segment,
425                 .gro_receive    = sit_ip6ip6_gro_receive,
426                 .gro_complete   = ip6ip6_gro_complete,
427         },
428 };
429 static int __init ipv6_offload_init(void)
430 {
431
432         if (tcpv6_offload_init() < 0)
433                 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
434         if (ipv6_exthdrs_offload_init() < 0)
435                 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
436
437         dev_add_offload(&ipv6_packet_offload);
438
439         inet_add_offload(&sit_offload, IPPROTO_IPV6);
440         inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
441         inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
442
443         return 0;
444 }
445
446 fs_initcall(ipv6_offload_init);