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
40static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
41{
42 const struct net_offload *ops = NULL;
43
44 for (;;) {
45 struct ipv6_opt_hdr *opth;
46 int len;
47
48 if (proto != NEXTHDR_HOP) {
49 ops = rcu_dereference(inet6_offloads[proto]);
50
51 if (unlikely(!ops))
52 break;
53
54 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
55 break;
56 }
57
58 if (unlikely(!pskb_may_pull(skb, 8)))
59 break;
60
61 opth = (void *)skb->data;
62 len = ipv6_optlen(opth);
63
64 if (unlikely(!pskb_may_pull(skb, len)))
65 break;
66
67 opth = (void *)skb->data;
68 proto = opth->nexthdr;
69 __skb_pull(skb, len);
70 }
71
72 return proto;
73}
74
75static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
76 netdev_features_t features)
77{
78 struct sk_buff *segs = ERR_PTR(error: -EINVAL);
79 struct ipv6hdr *ipv6h;
80 const struct net_offload *ops;
81 int proto, err;
82 struct frag_hdr *fptr;
83 unsigned int payload_len;
84 u8 *prevhdr;
85 int offset = 0;
86 bool encap, udpfrag;
87 int nhoff;
88 bool gso_partial;
89
90 skb_reset_network_header(skb);
91 err = ipv6_hopopt_jumbo_remove(skb);
92 if (err)
93 return ERR_PTR(error: err);
94 nhoff = skb_network_header(skb) - skb_mac_header(skb);
95 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
96 goto out;
97
98 encap = SKB_GSO_CB(skb)->encap_level > 0;
99 if (encap)
100 features &= skb->dev->hw_enc_features;
101 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
102
103 ipv6h = ipv6_hdr(skb);
104 __skb_pull(skb, len: sizeof(*ipv6h));
105 segs = ERR_PTR(error: -EPROTONOSUPPORT);
106
107 proto = ipv6_gso_pull_exthdrs(skb, proto: ipv6h->nexthdr);
108
109 if (skb->encapsulation &&
110 skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
111 udpfrag = proto == IPPROTO_UDP && encap &&
112 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
113 else
114 udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
115 (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
116
117 ops = rcu_dereference(inet6_offloads[proto]);
118 if (likely(ops && ops->callbacks.gso_segment)) {
119 skb_reset_transport_header(skb);
120 segs = ops->callbacks.gso_segment(skb, features);
121 if (!segs)
122 skb->network_header = skb_mac_header(skb) + nhoff - skb->head;
123 }
124
125 if (IS_ERR_OR_NULL(ptr: segs))
126 goto out;
127
128 gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
129
130 for (skb = segs; skb; skb = skb->next) {
131 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
132 if (gso_partial && skb_is_gso(skb))
133 payload_len = skb_shinfo(skb)->gso_size +
134 SKB_GSO_CB(skb)->data_offset +
135 skb->head - (unsigned char *)(ipv6h + 1);
136 else
137 payload_len = skb->len - nhoff - sizeof(*ipv6h);
138 ipv6h->payload_len = htons(payload_len);
139 skb->network_header = (u8 *)ipv6h - skb->head;
140 skb_reset_mac_len(skb);
141
142 if (udpfrag) {
143 int err = ip6_find_1stfragopt(skb, nexthdr: &prevhdr);
144 if (err < 0) {
145 kfree_skb_list(segs);
146 return ERR_PTR(error: err);
147 }
148 fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
149 fptr->frag_off = htons(offset);
150 if (skb->next)
151 fptr->frag_off |= htons(IP6_MF);
152 offset += (ntohs(ipv6h->payload_len) -
153 sizeof(struct frag_hdr));
154 }
155 if (encap)
156 skb_reset_inner_headers(skb);
157 }
158
159out:
160 return segs;
161}
162
163/* Return the total length of all the extension hdrs, following the same
164 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
165 */
166static int ipv6_exthdrs_len(struct ipv6hdr *iph,
167 const struct net_offload **opps)
168{
169 struct ipv6_opt_hdr *opth = (void *)iph;
170 int len = 0, proto, optlen = sizeof(*iph);
171
172 proto = iph->nexthdr;
173 for (;;) {
174 if (proto != NEXTHDR_HOP) {
175 *opps = rcu_dereference(inet6_offloads[proto]);
176 if (unlikely(!(*opps)))
177 break;
178 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
179 break;
180 }
181 opth = (void *)opth + optlen;
182 optlen = ipv6_optlen(opth);
183 len += optlen;
184 proto = opth->nexthdr;
185 }
186 return len;
187}
188
189INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
190 struct sk_buff *skb)
191{
192 const struct net_offload *ops;
193 struct sk_buff *pp = NULL;
194 struct sk_buff *p;
195 struct ipv6hdr *iph;
196 unsigned int nlen;
197 unsigned int hlen;
198 unsigned int off;
199 u16 flush = 1;
200 int proto;
201
202 off = skb_gro_offset(skb);
203 hlen = off + sizeof(*iph);
204 iph = skb_gro_header(skb, hlen, offset: off);
205 if (unlikely(!iph))
206 goto out;
207
208 skb_set_network_header(skb, offset: off);
209 skb_gro_pull(skb, len: sizeof(*iph));
210 skb_set_transport_header(skb, offset: skb_gro_offset(skb));
211
212 flush += ntohs(iph->payload_len) != skb_gro_len(skb);
213
214 proto = iph->nexthdr;
215 ops = rcu_dereference(inet6_offloads[proto]);
216 if (!ops || !ops->callbacks.gro_receive) {
217 pskb_pull(skb, len: skb_gro_offset(skb));
218 skb_gro_frag0_invalidate(skb);
219 proto = ipv6_gso_pull_exthdrs(skb, proto);
220 skb_gro_pull(skb, len: -skb_transport_offset(skb));
221 skb_reset_transport_header(skb);
222 __skb_push(skb, len: skb_gro_offset(skb));
223
224 ops = rcu_dereference(inet6_offloads[proto]);
225 if (!ops || !ops->callbacks.gro_receive)
226 goto out;
227
228 iph = ipv6_hdr(skb);
229 }
230
231 NAPI_GRO_CB(skb)->proto = proto;
232
233 flush--;
234 nlen = skb_network_header_len(skb);
235
236 list_for_each_entry(p, head, list) {
237 const struct ipv6hdr *iph2;
238 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
239
240 if (!NAPI_GRO_CB(p)->same_flow)
241 continue;
242
243 iph2 = (struct ipv6hdr *)(p->data + off);
244 first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
245
246 /* All fields must match except length and Traffic Class.
247 * XXX skbs on the gro_list have all been parsed and pulled
248 * already so we don't need to compare nlen
249 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
250 * memcmp() alone below is sufficient, right?
251 */
252 if ((first_word & htonl(0xF00FFFFF)) ||
253 !ipv6_addr_equal(a1: &iph->saddr, a2: &iph2->saddr) ||
254 !ipv6_addr_equal(a1: &iph->daddr, a2: &iph2->daddr) ||
255 iph->nexthdr != iph2->nexthdr) {
256not_same_flow:
257 NAPI_GRO_CB(p)->same_flow = 0;
258 continue;
259 }
260 if (unlikely(nlen > sizeof(struct ipv6hdr))) {
261 if (memcmp(p: iph + 1, q: iph2 + 1,
262 size: nlen - sizeof(struct ipv6hdr)))
263 goto not_same_flow;
264 }
265 /* flush if Traffic Class fields are different */
266 NAPI_GRO_CB(p)->flush |= !!((first_word & htonl(0x0FF00000)) |
267 (__force __be32)(iph->hop_limit ^ iph2->hop_limit));
268 NAPI_GRO_CB(p)->flush |= flush;
269
270 /* If the previous IP ID value was based on an atomic
271 * datagram we can overwrite the value and ignore it.
272 */
273 if (NAPI_GRO_CB(skb)->is_atomic)
274 NAPI_GRO_CB(p)->flush_id = 0;
275 }
276
277 NAPI_GRO_CB(skb)->is_atomic = true;
278 NAPI_GRO_CB(skb)->flush |= flush;
279
280 skb_gro_postpull_rcsum(skb, start: iph, len: nlen);
281
282 pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive,
283 ops->callbacks.gro_receive, head, skb);
284
285out:
286 skb_gro_flush_final(skb, pp, flush);
287
288 return pp;
289}
290
291static 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
306static 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
321INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
322{
323 const struct net_offload *ops;
324 struct ipv6hdr *iph;
325 int err = -ENOSYS;
326 u32 payload_len;
327
328 if (skb->encapsulation) {
329 skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
330 skb_set_inner_network_header(skb, offset: nhoff);
331 }
332
333 payload_len = skb->len - nhoff - sizeof(*iph);
334 if (unlikely(payload_len > IPV6_MAXPLEN)) {
335 struct hop_jumbo_hdr *hop_jumbo;
336 int hoplen = sizeof(*hop_jumbo);
337
338 /* Move network header left */
339 memmove(skb_mac_header(skb) - hoplen, skb_mac_header(skb),
340 skb->transport_header - skb->mac_header);
341 skb->data -= hoplen;
342 skb->len += hoplen;
343 skb->mac_header -= hoplen;
344 skb->network_header -= hoplen;
345 iph = (struct ipv6hdr *)(skb->data + nhoff);
346 hop_jumbo = (struct hop_jumbo_hdr *)(iph + 1);
347
348 /* Build hop-by-hop options */
349 hop_jumbo->nexthdr = iph->nexthdr;
350 hop_jumbo->hdrlen = 0;
351 hop_jumbo->tlv_type = IPV6_TLV_JUMBO;
352 hop_jumbo->tlv_len = 4;
353 hop_jumbo->jumbo_payload_len = htonl(payload_len + hoplen);
354
355 iph->nexthdr = NEXTHDR_HOP;
356 iph->payload_len = 0;
357 } else {
358 iph = (struct ipv6hdr *)(skb->data + nhoff);
359 iph->payload_len = htons(payload_len);
360 }
361
362 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, opps: &ops);
363 if (WARN_ON(!ops || !ops->callbacks.gro_complete))
364 goto out;
365
366 err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
367 udp6_gro_complete, skb, nhoff);
368
369out:
370 return err;
371}
372
373static int sit_gro_complete(struct sk_buff *skb, int nhoff)
374{
375 skb->encapsulation = 1;
376 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
377 return ipv6_gro_complete(skb, nhoff);
378}
379
380static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
381{
382 skb->encapsulation = 1;
383 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
384 return ipv6_gro_complete(skb, nhoff);
385}
386
387static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
388{
389 skb->encapsulation = 1;
390 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
391 return inet_gro_complete(skb, nhoff);
392}
393
394static struct packet_offload ipv6_packet_offload __read_mostly = {
395 .type = cpu_to_be16(ETH_P_IPV6),
396 .callbacks = {
397 .gso_segment = ipv6_gso_segment,
398 .gro_receive = ipv6_gro_receive,
399 .gro_complete = ipv6_gro_complete,
400 },
401};
402
403static struct sk_buff *sit_gso_segment(struct sk_buff *skb,
404 netdev_features_t features)
405{
406 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
407 return ERR_PTR(error: -EINVAL);
408
409 return ipv6_gso_segment(skb, features);
410}
411
412static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb,
413 netdev_features_t features)
414{
415 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
416 return ERR_PTR(error: -EINVAL);
417
418 return inet_gso_segment(skb, features);
419}
420
421static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb,
422 netdev_features_t features)
423{
424 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
425 return ERR_PTR(error: -EINVAL);
426
427 return ipv6_gso_segment(skb, features);
428}
429
430static const struct net_offload sit_offload = {
431 .callbacks = {
432 .gso_segment = sit_gso_segment,
433 .gro_receive = sit_ip6ip6_gro_receive,
434 .gro_complete = sit_gro_complete,
435 },
436};
437
438static const struct net_offload ip4ip6_offload = {
439 .callbacks = {
440 .gso_segment = ip4ip6_gso_segment,
441 .gro_receive = ip4ip6_gro_receive,
442 .gro_complete = ip4ip6_gro_complete,
443 },
444};
445
446static const struct net_offload ip6ip6_offload = {
447 .callbacks = {
448 .gso_segment = ip6ip6_gso_segment,
449 .gro_receive = sit_ip6ip6_gro_receive,
450 .gro_complete = ip6ip6_gro_complete,
451 },
452};
453static int __init ipv6_offload_init(void)
454{
455
456 if (tcpv6_offload_init() < 0)
457 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
458 if (ipv6_exthdrs_offload_init() < 0)
459 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
460
461 dev_add_offload(po: &ipv6_packet_offload);
462
463 inet_add_offload(prot: &sit_offload, IPPROTO_IPV6);
464 inet6_add_offload(prot: &ip6ip6_offload, IPPROTO_IPV6);
465 inet6_add_offload(prot: &ip4ip6_offload, IPPROTO_IPIP);
466
467 return 0;
468}
469
470fs_initcall(ipv6_offload_init);
471

source code of linux/net/ipv6/ip6_offload.c