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
ipv6_gso_pull_exthdrs(struct sk_buff * skb,int proto)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
ipv6_gso_segment(struct sk_buff * skb,netdev_features_t features)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 */
ipv6_exthdrs_len(struct ipv6hdr * iph,const struct net_offload ** opps)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
ipv6_gro_receive(struct list_head * head,struct sk_buff * skb)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
sit_ip6ip6_gro_receive(struct list_head * head,struct sk_buff * skb)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
ip4ip6_gro_receive(struct list_head * head,struct sk_buff * skb)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
ipv6_gro_complete(struct sk_buff * skb,int nhoff)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
sit_gro_complete(struct sk_buff * skb,int nhoff)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
ip6ip6_gro_complete(struct sk_buff * skb,int nhoff)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
ip4ip6_gro_complete(struct sk_buff * skb,int nhoff)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
sit_gso_segment(struct sk_buff * skb,netdev_features_t features)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
ip4ip6_gso_segment(struct sk_buff * skb,netdev_features_t features)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
ip6ip6_gso_segment(struct sk_buff * skb,netdev_features_t features)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 };
ipv6_offload_init(void)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);
447