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 #include <net/gso.h>
20
21 #include "ip6_offload.h"
22
23 /* All GRO functions are always builtin, except UDP over ipv6, which lays in
24 * ipv6 module, as it depends on UDPv6 lookup function, so we need special care
25 * when ipv6 is built as a module
26 */
27 #if IS_BUILTIN(CONFIG_IPV6)
28 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__)
29 #else
30 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_1(f, f2, __VA_ARGS__)
31 #endif
32
33 #define indirect_call_gro_receive_l4(f2, f1, cb, head, skb) \
34 ({ \
35 unlikely(gro_recursion_inc_test(skb)) ? \
36 NAPI_GRO_CB(skb)->flush |= 1, NULL : \
37 INDIRECT_CALL_L4(cb, f2, f1, head, skb); \
38 })
39
ipv6_gro_pull_exthdrs(struct sk_buff * skb,int off,int proto)40 static int ipv6_gro_pull_exthdrs(struct sk_buff *skb, int off, int proto)
41 {
42 const struct net_offload *ops = NULL;
43 struct ipv6_opt_hdr *opth;
44
45 for (;;) {
46 int len;
47
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 opth = skb_gro_header(skb, off + sizeof(*opth), off);
57 if (unlikely(!opth))
58 break;
59
60 len = ipv6_optlen(opth);
61
62 opth = skb_gro_header(skb, off + len, off);
63 if (unlikely(!opth))
64 break;
65 proto = opth->nexthdr;
66
67 off += len;
68 }
69
70 skb_gro_pull(skb, off - skb_gro_receive_network_offset(skb));
71 return proto;
72 }
73
ipv6_gso_pull_exthdrs(struct sk_buff * skb,int proto)74 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
75 {
76 const struct net_offload *ops = NULL;
77
78 for (;;) {
79 struct ipv6_opt_hdr *opth;
80 int len;
81
82 ops = rcu_dereference(inet6_offloads[proto]);
83
84 if (unlikely(!ops))
85 break;
86
87 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
88 break;
89
90 if (unlikely(!pskb_may_pull(skb, 8)))
91 break;
92
93 opth = (void *)skb->data;
94 len = ipv6_optlen(opth);
95
96 if (unlikely(!pskb_may_pull(skb, len)))
97 break;
98
99 opth = (void *)skb->data;
100 proto = opth->nexthdr;
101 __skb_pull(skb, len);
102 }
103
104 return proto;
105 }
106
ipv6_gso_segment(struct sk_buff * skb,netdev_features_t features)107 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
108 netdev_features_t features)
109 {
110 struct sk_buff *segs = ERR_PTR(-EINVAL);
111 struct ipv6hdr *ipv6h;
112 const struct net_offload *ops;
113 int proto, err;
114 struct frag_hdr *fptr;
115 unsigned int payload_len;
116 u8 *prevhdr;
117 int offset = 0;
118 bool encap, udpfrag;
119 int nhoff;
120 bool gso_partial;
121
122 skb_reset_network_header(skb);
123 err = ipv6_hopopt_jumbo_remove(skb);
124 if (err)
125 return ERR_PTR(err);
126 nhoff = skb_network_header(skb) - skb_mac_header(skb);
127 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
128 goto out;
129
130 encap = SKB_GSO_CB(skb)->encap_level > 0;
131 if (encap)
132 features &= skb->dev->hw_enc_features;
133 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
134
135 ipv6h = ipv6_hdr(skb);
136 __skb_pull(skb, sizeof(*ipv6h));
137 segs = ERR_PTR(-EPROTONOSUPPORT);
138
139 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
140
141 if (skb->encapsulation &&
142 skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
143 udpfrag = proto == IPPROTO_UDP && encap &&
144 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
145 else
146 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
147 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
148
149 ops = rcu_dereference(inet6_offloads[proto]);
150 if (likely(ops && ops->callbacks.gso_segment)) {
151 if (!skb_reset_transport_header_careful(skb))
152 goto out;
153
154 segs = ops->callbacks.gso_segment(skb, features);
155 if (!segs)
156 skb->network_header = skb_mac_header(skb) + nhoff - skb->head;
157 }
158
159 if (IS_ERR_OR_NULL(segs))
160 goto out;
161
162 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
163
164 for (skb = segs; skb; skb = skb->next) {
165 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
166 if (gso_partial && skb_is_gso(skb))
167 payload_len = skb_shinfo(skb)->gso_size +
168 SKB_GSO_CB(skb)->data_offset +
169 skb->head - (unsigned char *)(ipv6h + 1);
170 else
171 payload_len = skb->len - nhoff - sizeof(*ipv6h);
172 ipv6h->payload_len = htons(payload_len);
173 skb->network_header = (u8 *)ipv6h - skb->head;
174 skb_reset_mac_len(skb);
175
176 if (udpfrag) {
177 int err = ip6_find_1stfragopt(skb, &prevhdr);
178 if (err < 0) {
179 kfree_skb_list(segs);
180 return ERR_PTR(err);
181 }
182 fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
183 fptr->frag_off = htons(offset);
184 if (skb->next)
185 fptr->frag_off |= htons(IP6_MF);
186 offset += (ntohs(ipv6h->payload_len) -
187 sizeof(struct frag_hdr));
188 }
189 if (encap)
190 skb_reset_inner_headers(skb);
191 }
192
193 out:
194 return segs;
195 }
196
197 /* Return the total length of all the extension hdrs, following the same
198 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
199 */
ipv6_exthdrs_len(struct ipv6hdr * iph,const struct net_offload ** opps)200 static int ipv6_exthdrs_len(struct ipv6hdr *iph,
201 const struct net_offload **opps)
202 {
203 struct ipv6_opt_hdr *opth = (void *)iph;
204 int len = 0, proto, optlen = sizeof(*iph);
205
206 proto = iph->nexthdr;
207 for (;;) {
208 *opps = rcu_dereference(inet6_offloads[proto]);
209 if (unlikely(!(*opps)))
210 break;
211 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
212 break;
213
214 opth = (void *)opth + optlen;
215 optlen = ipv6_optlen(opth);
216 len += optlen;
217 proto = opth->nexthdr;
218 }
219 return len;
220 }
221
ipv6_gro_receive(struct list_head * head,struct sk_buff * skb)222 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
223 struct sk_buff *skb)
224 {
225 const struct net_offload *ops;
226 struct sk_buff *pp = NULL;
227 struct sk_buff *p;
228 struct ipv6hdr *iph;
229 unsigned int nlen;
230 unsigned int hlen;
231 unsigned int off;
232 u16 flush = 1;
233 int proto;
234
235 off = skb_gro_offset(skb);
236 hlen = off + sizeof(*iph);
237 iph = skb_gro_header(skb, hlen, off);
238 if (unlikely(!iph))
239 goto out;
240
241 NAPI_GRO_CB(skb)->network_offsets[NAPI_GRO_CB(skb)->encap_mark] = off;
242
243 flush += ntohs(iph->payload_len) != skb->len - hlen;
244
245 proto = iph->nexthdr;
246 ops = rcu_dereference(inet6_offloads[proto]);
247 if (!ops || !ops->callbacks.gro_receive) {
248 proto = ipv6_gro_pull_exthdrs(skb, hlen, proto);
249
250 ops = rcu_dereference(inet6_offloads[proto]);
251 if (!ops || !ops->callbacks.gro_receive)
252 goto out;
253
254 iph = skb_gro_network_header(skb);
255 } else {
256 skb_gro_pull(skb, sizeof(*iph));
257 }
258
259 skb_set_transport_header(skb, skb_gro_offset(skb));
260
261 NAPI_GRO_CB(skb)->proto = proto;
262
263 flush--;
264 nlen = skb_gro_offset(skb) - off;
265
266 list_for_each_entry(p, head, list) {
267 const struct ipv6hdr *iph2;
268 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
269
270 if (!NAPI_GRO_CB(p)->same_flow)
271 continue;
272
273 iph2 = (struct ipv6hdr *)(p->data + off);
274 first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
275
276 /* All fields must match except length and Traffic Class.
277 * XXX skbs on the gro_list have all been parsed and pulled
278 * already so we don't need to compare nlen
279 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
280 * memcmp() alone below is sufficient, right?
281 */
282 if ((first_word & htonl(0xF00FFFFF)) ||
283 !ipv6_addr_equal(&iph->saddr, &iph2->saddr) ||
284 !ipv6_addr_equal(&iph->daddr, &iph2->daddr) ||
285 iph->nexthdr != iph2->nexthdr) {
286 not_same_flow:
287 NAPI_GRO_CB(p)->same_flow = 0;
288 continue;
289 }
290 if (unlikely(nlen > sizeof(struct ipv6hdr))) {
291 if (memcmp(iph + 1, iph2 + 1,
292 nlen - sizeof(struct ipv6hdr)))
293 goto not_same_flow;
294 }
295 }
296
297 NAPI_GRO_CB(skb)->flush |= flush;
298
299 skb_gro_postpull_rcsum(skb, iph, nlen);
300
301 pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive,
302 ops->callbacks.gro_receive, head, skb);
303
304 out:
305 skb_gro_flush_final(skb, pp, flush);
306
307 return pp;
308 }
309
sit_ip6ip6_gro_receive(struct list_head * head,struct sk_buff * skb)310 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
311 struct sk_buff *skb)
312 {
313 /* Common GRO receive for SIT and IP6IP6 */
314
315 if (NAPI_GRO_CB(skb)->encap_mark) {
316 NAPI_GRO_CB(skb)->flush = 1;
317 return NULL;
318 }
319
320 NAPI_GRO_CB(skb)->encap_mark = 1;
321
322 return ipv6_gro_receive(head, skb);
323 }
324
ip4ip6_gro_receive(struct list_head * head,struct sk_buff * skb)325 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
326 struct sk_buff *skb)
327 {
328 /* Common GRO receive for SIT and IP6IP6 */
329
330 if (NAPI_GRO_CB(skb)->encap_mark) {
331 NAPI_GRO_CB(skb)->flush = 1;
332 return NULL;
333 }
334
335 NAPI_GRO_CB(skb)->encap_mark = 1;
336
337 return inet_gro_receive(head, skb);
338 }
339
ipv6_gro_complete(struct sk_buff * skb,int nhoff)340 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
341 {
342 const struct net_offload *ops;
343 struct ipv6hdr *iph;
344 int err = -ENOSYS;
345 u32 payload_len;
346
347 if (skb->encapsulation) {
348 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
349 skb_set_inner_network_header(skb, nhoff);
350 }
351
352 payload_len = skb->len - nhoff - sizeof(*iph);
353 if (unlikely(payload_len > IPV6_MAXPLEN)) {
354 struct hop_jumbo_hdr *hop_jumbo;
355 int hoplen = sizeof(*hop_jumbo);
356
357 /* Move network header left */
358 memmove(skb_mac_header(skb) - hoplen, skb_mac_header(skb),
359 skb->transport_header - skb->mac_header);
360 skb->data -= hoplen;
361 skb->len += hoplen;
362 skb->mac_header -= hoplen;
363 skb->network_header -= hoplen;
364 iph = (struct ipv6hdr *)(skb->data + nhoff);
365 hop_jumbo = (struct hop_jumbo_hdr *)(iph + 1);
366
367 /* Build hop-by-hop options */
368 hop_jumbo->nexthdr = iph->nexthdr;
369 hop_jumbo->hdrlen = 0;
370 hop_jumbo->tlv_type = IPV6_TLV_JUMBO;
371 hop_jumbo->tlv_len = 4;
372 hop_jumbo->jumbo_payload_len = htonl(payload_len + hoplen);
373
374 iph->nexthdr = NEXTHDR_HOP;
375 iph->payload_len = 0;
376 } else {
377 iph = (struct ipv6hdr *)(skb->data + nhoff);
378 iph->payload_len = htons(payload_len);
379 }
380
381 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
382 if (WARN_ON(!ops || !ops->callbacks.gro_complete))
383 goto out;
384
385 err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
386 udp6_gro_complete, skb, nhoff);
387
388 out:
389 return err;
390 }
391
sit_gro_complete(struct sk_buff * skb,int nhoff)392 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
393 {
394 skb->encapsulation = 1;
395 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
396 return ipv6_gro_complete(skb, nhoff);
397 }
398
ip6ip6_gro_complete(struct sk_buff * skb,int nhoff)399 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
400 {
401 skb->encapsulation = 1;
402 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
403 return ipv6_gro_complete(skb, nhoff);
404 }
405
ip4ip6_gro_complete(struct sk_buff * skb,int nhoff)406 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
407 {
408 skb->encapsulation = 1;
409 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
410 return inet_gro_complete(skb, nhoff);
411 }
412
413
sit_gso_segment(struct sk_buff * skb,netdev_features_t features)414 static struct sk_buff *sit_gso_segment(struct sk_buff *skb,
415 netdev_features_t features)
416 {
417 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
418 return ERR_PTR(-EINVAL);
419
420 return ipv6_gso_segment(skb, features);
421 }
422
ip4ip6_gso_segment(struct sk_buff * skb,netdev_features_t features)423 static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb,
424 netdev_features_t features)
425 {
426 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
427 return ERR_PTR(-EINVAL);
428
429 return inet_gso_segment(skb, features);
430 }
431
ip6ip6_gso_segment(struct sk_buff * skb,netdev_features_t features)432 static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb,
433 netdev_features_t features)
434 {
435 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
436 return ERR_PTR(-EINVAL);
437
438 return ipv6_gso_segment(skb, features);
439 }
440
441 static const struct net_offload sit_offload = {
442 .callbacks = {
443 .gso_segment = sit_gso_segment,
444 .gro_receive = sit_ip6ip6_gro_receive,
445 .gro_complete = sit_gro_complete,
446 },
447 };
448
449 static const struct net_offload ip4ip6_offload = {
450 .callbacks = {
451 .gso_segment = ip4ip6_gso_segment,
452 .gro_receive = ip4ip6_gro_receive,
453 .gro_complete = ip4ip6_gro_complete,
454 },
455 };
456
457 static const struct net_offload ip6ip6_offload = {
458 .callbacks = {
459 .gso_segment = ip6ip6_gso_segment,
460 .gro_receive = sit_ip6ip6_gro_receive,
461 .gro_complete = ip6ip6_gro_complete,
462 },
463 };
ipv6_offload_init(void)464 static int __init ipv6_offload_init(void)
465 {
466
467 if (tcpv6_offload_init() < 0)
468 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
469 if (ipv6_exthdrs_offload_init() < 0)
470 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
471
472 net_hotdata.ipv6_packet_offload = (struct packet_offload) {
473 .type = cpu_to_be16(ETH_P_IPV6),
474 .callbacks = {
475 .gso_segment = ipv6_gso_segment,
476 .gro_receive = ipv6_gro_receive,
477 .gro_complete = ipv6_gro_complete,
478 },
479 };
480 dev_add_offload(&net_hotdata.ipv6_packet_offload);
481
482 inet_add_offload(&sit_offload, IPPROTO_IPV6);
483 inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
484 inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
485
486 return 0;
487 }
488
489 fs_initcall(ipv6_offload_init);
490