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
17 #include "ip6_offload.h"
18
19 /* All GRO functions are always builtin, except UDP over ipv6, which lays in
20 * ipv6 module, as it depends on UDPv6 lookup function, so we need special care
21 * when ipv6 is built as a module
22 */
23 #if IS_BUILTIN(CONFIG_IPV6)
24 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__)
25 #else
26 #define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_1(f, f2, __VA_ARGS__)
27 #endif
28
29 #define indirect_call_gro_receive_l4(f2, f1, cb, head, skb) \
30 ({ \
31 unlikely(gro_recursion_inc_test(skb)) ? \
32 NAPI_GRO_CB(skb)->flush |= 1, NULL : \
33 INDIRECT_CALL_L4(cb, f2, f1, head, skb); \
34 })
35
36 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
37 {
38 const struct net_offload *ops = NULL;
39
40 for (;;) {
41 struct ipv6_opt_hdr *opth;
42 int len;
43
44 if (proto != NEXTHDR_HOP) {
45 ops = rcu_dereference(inet6_offloads[proto]);
46
47 if (unlikely(!ops))
48 break;
49
50 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
51 break;
52 }
53
54 if (unlikely(!pskb_may_pull(skb, 8)))
55 break;
56
57 opth = (void *)skb->data;
58 len = ipv6_optlen(opth);
59
60 if (unlikely(!pskb_may_pull(skb, len)))
61 break;
62
63 opth = (void *)skb->data;
64 proto = opth->nexthdr;
65 __skb_pull(skb, len);
66 }
67
68 return proto;
69 }
70
71 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
72 netdev_features_t features)
73 {
74 struct sk_buff *segs = ERR_PTR(-EINVAL);
75 struct ipv6hdr *ipv6h;
76 const struct net_offload *ops;
77 int proto;
78 struct frag_hdr *fptr;
79 unsigned int payload_len;
80 u8 *prevhdr;
81 int offset = 0;
82 bool encap, udpfrag;
83 int nhoff;
84 bool gso_partial;
85
86 skb_reset_network_header(skb);
87 nhoff = skb_network_header(skb) - skb_mac_header(skb);
88 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
89 goto out;
90
91 encap = SKB_GSO_CB(skb)->encap_level > 0;
92 if (encap)
93 features &= skb->dev->hw_enc_features;
94 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
95
96 ipv6h = ipv6_hdr(skb);
97 __skb_pull(skb, sizeof(*ipv6h));
98 segs = ERR_PTR(-EPROTONOSUPPORT);
99
100 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
101
102 if (skb->encapsulation &&
103 skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
104 udpfrag = proto == IPPROTO_UDP && encap &&
105 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
106 else
107 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
108 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
109
110 ops = rcu_dereference(inet6_offloads[proto]);
111 if (likely(ops && ops->callbacks.gso_segment)) {
112 skb_reset_transport_header(skb);
113 segs = ops->callbacks.gso_segment(skb, features);
114 }
115
116 if (IS_ERR_OR_NULL(segs))
117 goto out;
118
119 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
120
121 for (skb = segs; skb; skb = skb->next) {
122 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
123 if (gso_partial && skb_is_gso(skb))
124 payload_len = skb_shinfo(skb)->gso_size +
125 SKB_GSO_CB(skb)->data_offset +
126 skb->head - (unsigned char *)(ipv6h + 1);
127 else
128 payload_len = skb->len - nhoff - sizeof(*ipv6h);
129 ipv6h->payload_len = htons(payload_len);
130 skb->network_header = (u8 *)ipv6h - skb->head;
131 skb_reset_mac_len(skb);
132
133 if (udpfrag) {
134 int err = ip6_find_1stfragopt(skb, &prevhdr);
135 if (err < 0) {
136 kfree_skb_list(segs);
137 return ERR_PTR(err);
138 }
139 fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
140 fptr->frag_off = htons(offset);
141 if (skb->next)
142 fptr->frag_off |= htons(IP6_MF);
143 offset += (ntohs(ipv6h->payload_len) -
144 sizeof(struct frag_hdr));
145 }
146 if (encap)
147 skb_reset_inner_headers(skb);
148 }
149
150 out:
151 return segs;
152 }
153
154 /* Return the total length of all the extension hdrs, following the same
155 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
156 */
157 static int ipv6_exthdrs_len(struct ipv6hdr *iph,
158 const struct net_offload **opps)
159 {
160 struct ipv6_opt_hdr *opth = (void *)iph;
161 int len = 0, proto, optlen = sizeof(*iph);
162
163 proto = iph->nexthdr;
164 for (;;) {
165 if (proto != NEXTHDR_HOP) {
166 *opps = rcu_dereference(inet6_offloads[proto]);
167 if (unlikely(!(*opps)))
168 break;
169 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
170 break;
171 }
172 opth = (void *)opth + optlen;
173 optlen = ipv6_optlen(opth);
174 len += optlen;
175 proto = opth->nexthdr;
176 }
177 return len;
178 }
179
180 INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *,
181 struct sk_buff *));
182 INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp6_gro_receive(struct list_head *,
183 struct sk_buff *));
184 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
185 struct sk_buff *skb)
186 {
187 const struct net_offload *ops;
188 struct sk_buff *pp = NULL;
189 struct sk_buff *p;
190 struct ipv6hdr *iph;
191 unsigned int nlen;
192 unsigned int hlen;
193 unsigned int off;
194 u16 flush = 1;
195 int proto;
196
197 off = skb_gro_offset(skb);
198 hlen = off + sizeof(*iph);
199 iph = skb_gro_header_fast(skb, off);
200 if (skb_gro_header_hard(skb, hlen)) {
201 iph = skb_gro_header_slow(skb, hlen, off);
202 if (unlikely(!iph))
203 goto out;
204 }
205
206 skb_set_network_header(skb, off);
207 skb_gro_pull(skb, sizeof(*iph));
208 skb_set_transport_header(skb, skb_gro_offset(skb));
209
210 flush += ntohs(iph->payload_len) != skb_gro_len(skb);
211
212 rcu_read_lock();
213 proto = iph->nexthdr;
214 ops = rcu_dereference(inet6_offloads[proto]);
215 if (!ops || !ops->callbacks.gro_receive) {
216 __pskb_pull(skb, skb_gro_offset(skb));
217 skb_gro_frag0_invalidate(skb);
218 proto = ipv6_gso_pull_exthdrs(skb, proto);
219 skb_gro_pull(skb, -skb_transport_offset(skb));
220 skb_reset_transport_header(skb);
221 __skb_push(skb, skb_gro_offset(skb));
222
223 ops = rcu_dereference(inet6_offloads[proto]);
224 if (!ops || !ops->callbacks.gro_receive)
225 goto out_unlock;
226
227 iph = ipv6_hdr(skb);
228 }
229
230 NAPI_GRO_CB(skb)->proto = proto;
231
232 flush--;
233 nlen = skb_network_header_len(skb);
234
235 list_for_each_entry(p, head, list) {
236 const struct ipv6hdr *iph2;
237 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
238
239 if (!NAPI_GRO_CB(p)->same_flow)
240 continue;
241
242 iph2 = (struct ipv6hdr *)(p->data + off);
243 first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
244
245 /* All fields must match except length and Traffic Class.
246 * XXX skbs on the gro_list have all been parsed and pulled
247 * already so we don't need to compare nlen
248 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
249 * memcmp() alone below is sufficient, right?
250 */
251 if ((first_word & htonl(0xF00FFFFF)) ||
252 !ipv6_addr_equal(&iph->saddr, &iph2->saddr) ||
253 !ipv6_addr_equal(&iph->daddr, &iph2->daddr) ||
254 *(u16 *)&iph->nexthdr != *(u16 *)&iph2->nexthdr) {
255 not_same_flow:
256 NAPI_GRO_CB(p)->same_flow = 0;
257 continue;
258 }
259 if (unlikely(nlen > sizeof(struct ipv6hdr))) {
260 if (memcmp(iph + 1, iph2 + 1,
261 nlen - sizeof(struct ipv6hdr)))
262 goto not_same_flow;
263 }
264 /* flush if Traffic Class fields are different */
265 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000));
266 NAPI_GRO_CB(p)->flush |= flush;
267
268 /* If the previous IP ID value was based on an atomic
269 * datagram we can overwrite the value and ignore it.
270 */
271 if (NAPI_GRO_CB(skb)->is_atomic)
272 NAPI_GRO_CB(p)->flush_id = 0;
273 }
274
275 NAPI_GRO_CB(skb)->is_atomic = true;
276 NAPI_GRO_CB(skb)->flush |= flush;
277
278 skb_gro_postpull_rcsum(skb, iph, nlen);
279
280 pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive,
281 ops->callbacks.gro_receive, head, skb);
282
283 out_unlock:
284 rcu_read_unlock();
285
286 out:
287 skb_gro_flush_final(skb, pp, flush);
288
289 return pp;
290 }
291
292 static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
293 struct sk_buff *skb)
294 {
295 /* Common GRO receive for SIT and IP6IP6 */
296
297 if (NAPI_GRO_CB(skb)->encap_mark) {
298 NAPI_GRO_CB(skb)->flush = 1;
299 return NULL;
300 }
301
302 NAPI_GRO_CB(skb)->encap_mark = 1;
303
304 return ipv6_gro_receive(head, skb);
305 }
306
307 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
308 struct sk_buff *skb)
309 {
310 /* Common GRO receive for SIT and IP6IP6 */
311
312 if (NAPI_GRO_CB(skb)->encap_mark) {
313 NAPI_GRO_CB(skb)->flush = 1;
314 return NULL;
315 }
316
317 NAPI_GRO_CB(skb)->encap_mark = 1;
318
319 return inet_gro_receive(head, skb);
320 }
321
322 INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *, int));
323 INDIRECT_CALLABLE_DECLARE(int udp6_gro_complete(struct sk_buff *, int));
324 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
325 {
326 const struct net_offload *ops;
327 struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
328 int err = -ENOSYS;
329
330 if (skb->encapsulation) {
331 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
332 skb_set_inner_network_header(skb, nhoff);
333 }
334
335 iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
336
337 rcu_read_lock();
338
339 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
340 if (WARN_ON(!ops || !ops->callbacks.gro_complete))
341 goto out_unlock;
342
343 err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
344 udp6_gro_complete, skb, nhoff);
345
346 out_unlock:
347 rcu_read_unlock();
348
349 return err;
350 }
351
352 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
353 {
354 skb->encapsulation = 1;
355 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
356 return ipv6_gro_complete(skb, nhoff);
357 }
358
359 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
360 {
361 skb->encapsulation = 1;
362 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
363 return ipv6_gro_complete(skb, nhoff);
364 }
365
366 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
367 {
368 skb->encapsulation = 1;
369 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
370 return inet_gro_complete(skb, nhoff);
371 }
372
373 static struct packet_offload ipv6_packet_offload __read_mostly = {
374 .type = cpu_to_be16(ETH_P_IPV6),
375 .callbacks = {
376 .gso_segment = ipv6_gso_segment,
377 .gro_receive = ipv6_gro_receive,
378 .gro_complete = ipv6_gro_complete,
379 },
380 };
381
382 static struct sk_buff *sit_gso_segment(struct sk_buff *skb,
383 netdev_features_t features)
384 {
385 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
386 return ERR_PTR(-EINVAL);
387
388 return ipv6_gso_segment(skb, features);
389 }
390
391 static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb,
392 netdev_features_t features)
393 {
394 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
395 return ERR_PTR(-EINVAL);
396
397 return inet_gso_segment(skb, features);
398 }
399
400 static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb,
401 netdev_features_t features)
402 {
403 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
404 return ERR_PTR(-EINVAL);
405
406 return ipv6_gso_segment(skb, features);
407 }
408
409 static const struct net_offload sit_offload = {
410 .callbacks = {
411 .gso_segment = sit_gso_segment,
412 .gro_receive = sit_ip6ip6_gro_receive,
413 .gro_complete = sit_gro_complete,
414 },
415 };
416
417 static const struct net_offload ip4ip6_offload = {
418 .callbacks = {
419 .gso_segment = ip4ip6_gso_segment,
420 .gro_receive = ip4ip6_gro_receive,
421 .gro_complete = ip4ip6_gro_complete,
422 },
423 };
424
425 static const struct net_offload ip6ip6_offload = {
426 .callbacks = {
427 .gso_segment = ip6ip6_gso_segment,
428 .gro_receive = sit_ip6ip6_gro_receive,
429 .gro_complete = ip6ip6_gro_complete,
430 },
431 };
432 static int __init ipv6_offload_init(void)
433 {
434
435 if (tcpv6_offload_init() < 0)
436 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
437 if (ipv6_exthdrs_offload_init() < 0)
438 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
439
440 dev_add_offload(&ipv6_packet_offload);
441
442 inet_add_offload(&sit_offload, IPPROTO_IPV6);
443 inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
444 inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
445
446 return 0;
447 }
448
449 fs_initcall(ipv6_offload_init);
450
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