xref: /linux/net/ipv6/ip6_offload.c (revision 259c4a519100e9182f264f8009ee212b32774277) 
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 #include <net/ip_tunnels.h>
21 
22 #include "ip6_offload.h"
23 #include "tcpv6_offload.c"
24 
25 static int ipv6_gro_pull_exthdrs(struct sk_buff *skb, int off, int proto)
26 {
27 	const struct net_offload *ops = NULL;
28 	struct ipv6_opt_hdr *opth;
29 
30 	for (;;) {
31 		int len;
32 
33 		ops = rcu_dereference(inet6_offloads[proto]);
34 
35 		if (unlikely(!ops))
36 			break;
37 
38 		if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
39 			break;
40 
41 		opth = skb_gro_header(skb, off + sizeof(*opth), off);
42 		if (unlikely(!opth))
43 			break;
44 
45 		len = ipv6_optlen(opth);
46 
47 		opth = skb_gro_header(skb, off + len, off);
48 		if (unlikely(!opth))
49 			break;
50 		proto = opth->nexthdr;
51 
52 		off += len;
53 	}
54 
55 	skb_gro_pull(skb, off - skb_gro_receive_network_offset(skb));
56 	return proto;
57 }
58 
59 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
60 {
61 	const struct net_offload *ops = NULL;
62 
63 	for (;;) {
64 		struct ipv6_opt_hdr *opth;
65 		int len;
66 
67 		ops = rcu_dereference(inet6_offloads[proto]);
68 
69 		if (unlikely(!ops))
70 			break;
71 
72 		if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
73 			break;
74 
75 		if (unlikely(!pskb_may_pull(skb, 8)))
76 			break;
77 
78 		opth = (void *)skb->data;
79 		len = ipv6_optlen(opth);
80 
81 		if (unlikely(!pskb_may_pull(skb, len)))
82 			break;
83 
84 		opth = (void *)skb->data;
85 		proto = opth->nexthdr;
86 		__skb_pull(skb, len);
87 	}
88 
89 	return proto;
90 }
91 
92 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
93 	netdev_features_t features)
94 {
95 	struct sk_buff *segs = ERR_PTR(-EINVAL);
96 	struct ipv6hdr *ipv6h;
97 	const struct net_offload *ops;
98 	int proto;
99 	struct frag_hdr *fptr;
100 	unsigned int payload_len;
101 	u8 *prevhdr;
102 	int offset = 0;
103 	bool encap, udpfrag;
104 	int nhoff;
105 	bool gso_partial;
106 
107 	skb_reset_network_header(skb);
108 	if (unlikely(gso_recursion_inc_test(skb,
109 					   IP_TUNNEL_RECURSION_LIMIT)))
110 		goto out;
111 	nhoff = skb_network_header(skb) - skb_mac_header(skb);
112 	if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
113 		goto out;
114 
115 	encap = SKB_GSO_CB(skb)->encap_level > 0;
116 	if (encap)
117 		features &= skb->dev->hw_enc_features;
118 	SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
119 
120 	ipv6h = ipv6_hdr(skb);
121 	__skb_pull(skb, sizeof(*ipv6h));
122 	segs = ERR_PTR(-EPROTONOSUPPORT);
123 
124 	proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
125 
126 	if (skb->encapsulation &&
127 	    skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
128 		udpfrag = proto == IPPROTO_UDP && encap &&
129 			  (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
130 	else
131 		udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
132 			  (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
133 
134 	ops = rcu_dereference(inet6_offloads[proto]);
135 	if (likely(ops && ops->callbacks.gso_segment)) {
136 		if (!skb_reset_transport_header_careful(skb))
137 			goto out;
138 
139 		segs = ops->callbacks.gso_segment(skb, features);
140 		if (!segs)
141 			skb->network_header = skb_mac_header(skb) + nhoff - skb->head;
142 	}
143 
144 	if (IS_ERR_OR_NULL(segs))
145 		goto out;
146 
147 	gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
148 
149 	for (skb = segs; skb; skb = skb->next) {
150 		ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
151 		if (gso_partial && skb_is_gso(skb))
152 			payload_len = skb_shinfo(skb)->gso_size +
153 				      SKB_GSO_CB(skb)->data_offset +
154 				      skb->head - (unsigned char *)(ipv6h + 1);
155 		else
156 			payload_len = skb->len - nhoff - sizeof(*ipv6h);
157 		ipv6h->payload_len = htons(payload_len);
158 		skb->network_header = (u8 *)ipv6h - skb->head;
159 		skb_reset_mac_len(skb);
160 
161 		if (udpfrag) {
162 			int err = ip6_find_1stfragopt(skb, &prevhdr);
163 			if (err < 0) {
164 				kfree_skb_list(segs);
165 				return ERR_PTR(err);
166 			}
167 			fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
168 			fptr->frag_off = htons(offset);
169 			if (skb->next)
170 				fptr->frag_off |= htons(IP6_MF);
171 			offset += (ntohs(ipv6h->payload_len) -
172 				   sizeof(struct frag_hdr));
173 		}
174 		if (encap)
175 			skb_reset_inner_headers(skb);
176 	}
177 
178 out:
179 	return segs;
180 }
181 
182 /* Return the total length of all the extension hdrs, following the same
183  * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
184  */
185 static int ipv6_exthdrs_len(struct ipv6hdr *iph,
186 			    const struct net_offload **opps)
187 {
188 	struct ipv6_opt_hdr *opth = (void *)iph;
189 	int len = 0, proto, optlen = sizeof(*iph);
190 
191 	proto = iph->nexthdr;
192 	for (;;) {
193 		*opps = rcu_dereference(inet6_offloads[proto]);
194 		if (unlikely(!(*opps)))
195 			break;
196 		if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
197 			break;
198 
199 		opth = (void *)opth + optlen;
200 		optlen = ipv6_optlen(opth);
201 		len += optlen;
202 		proto = opth->nexthdr;
203 	}
204 	return len;
205 }
206 
207 INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
208 							 struct sk_buff *skb)
209 {
210 	const struct net_offload *ops;
211 	struct sk_buff *pp = NULL;
212 	struct sk_buff *p;
213 	struct ipv6hdr *iph;
214 	unsigned int nlen;
215 	unsigned int hlen;
216 	unsigned int off;
217 	u16 flush = 1;
218 	int proto;
219 
220 	off = skb_gro_offset(skb);
221 	hlen = off + sizeof(*iph);
222 	iph = skb_gro_header(skb, hlen, off);
223 	if (unlikely(!iph))
224 		goto out;
225 
226 	NAPI_GRO_CB(skb)->network_offsets[NAPI_GRO_CB(skb)->encap_mark] = off;
227 
228 	flush += ntohs(iph->payload_len) != skb->len - hlen;
229 
230 	proto = iph->nexthdr;
231 	ops = rcu_dereference(inet6_offloads[proto]);
232 	if (!ops || !ops->callbacks.gro_receive) {
233 		proto = ipv6_gro_pull_exthdrs(skb, hlen, proto);
234 
235 		ops = rcu_dereference(inet6_offloads[proto]);
236 		if (!ops || !ops->callbacks.gro_receive)
237 			goto out;
238 
239 		iph = skb_gro_network_header(skb);
240 	} else {
241 		skb_gro_pull(skb, sizeof(*iph));
242 	}
243 
244 	skb_set_transport_header(skb, skb_gro_offset(skb));
245 
246 	NAPI_GRO_CB(skb)->proto = proto;
247 
248 	flush--;
249 	nlen = skb_gro_offset(skb) - off;
250 
251 	list_for_each_entry(p, head, list) {
252 		const struct ipv6hdr *iph2;
253 		__be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
254 
255 		if (!NAPI_GRO_CB(p)->same_flow)
256 			continue;
257 
258 		iph2 = (struct ipv6hdr *)(p->data + off);
259 		first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
260 
261 		/* All fields must match except length and Traffic Class.
262 		 * XXX skbs on the gro_list have all been parsed and pulled
263 		 * already so we don't need to compare nlen
264 		 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
265 		 * memcmp() alone below is sufficient, right?
266 		 */
267 		 if ((first_word & htonl(0xF00FFFFF)) ||
268 		     !ipv6_addr_equal(&iph->saddr, &iph2->saddr) ||
269 		     !ipv6_addr_equal(&iph->daddr, &iph2->daddr) ||
270 		     iph->nexthdr != iph2->nexthdr) {
271 not_same_flow:
272 			NAPI_GRO_CB(p)->same_flow = 0;
273 			continue;
274 		}
275 		if (unlikely(nlen > sizeof(struct ipv6hdr))) {
276 			if (memcmp(iph + 1, iph2 + 1,
277 				   nlen - sizeof(struct ipv6hdr)))
278 				goto not_same_flow;
279 		}
280 	}
281 
282 	NAPI_GRO_CB(skb)->flush |= flush;
283 
284 	skb_gro_postpull_rcsum(skb, iph, nlen);
285 
286 	if (unlikely(gro_recursion_inc_test(skb))) {
287 		flush = 1;
288 		goto out;
289 	}
290 
291 	if (likely(proto == IPPROTO_TCP))
292 		pp = tcp6_gro_receive(head, skb);
293 #if IS_ENABLED(CONFIG_IPV6)
294 	else if (likely(proto == IPPROTO_UDP))
295 		pp = udp6_gro_receive(head, skb);
296 #endif
297 	else
298 		pp = ops->callbacks.gro_receive(head, skb);
299 out:
300 	skb_gro_flush_final(skb, pp, flush);
301 
302 	return pp;
303 }
304 EXPORT_INDIRECT_CALLABLE(ipv6_gro_receive);
305 
306 static struct sk_buff *sit_ip6ip6_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 ipv6_gro_receive(head, skb);
319 }
320 
321 static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
322 					  struct sk_buff *skb)
323 {
324 	/* Common GRO receive for SIT and IP6IP6 */
325 
326 	if (NAPI_GRO_CB(skb)->encap_mark) {
327 		NAPI_GRO_CB(skb)->flush = 1;
328 		return NULL;
329 	}
330 
331 	NAPI_GRO_CB(skb)->encap_mark = 1;
332 
333 	return inet_gro_receive(head, skb);
334 }
335 
336 INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
337 {
338 	const struct net_offload *ops;
339 	struct ipv6hdr *iph;
340 	int err = -ENOSYS;
341 
342 	if (skb->encapsulation) {
343 		skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
344 		skb_set_inner_network_header(skb, nhoff);
345 	}
346 
347 	iph = (struct ipv6hdr *)(skb->data + nhoff);
348 	ipv6_set_payload_len(iph, skb->len - nhoff - sizeof(*iph));
349 
350 	nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
351 
352 	if (likely(ops == &net_hotdata.tcpv6_offload))
353 		return tcp6_gro_complete(skb, nhoff);
354 #if IS_ENABLED(CONFIG_IPV6)
355 	if (ops == &net_hotdata.udpv6_offload)
356 		return udp6_gro_complete(skb, nhoff);
357 #endif
358 
359 	if (WARN_ON(!ops || !ops->callbacks.gro_complete))
360 		goto out;
361 
362 	err = ops->callbacks.gro_complete(skb, nhoff);
363 
364 out:
365 	return err;
366 }
367 EXPORT_INDIRECT_CALLABLE(ipv6_gro_complete);
368 
369 static int sit_gro_complete(struct sk_buff *skb, int nhoff)
370 {
371 	skb->encapsulation = 1;
372 	skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
373 	return ipv6_gro_complete(skb, nhoff);
374 }
375 
376 static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
377 {
378 	skb->encapsulation = 1;
379 	skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
380 	return ipv6_gro_complete(skb, nhoff);
381 }
382 
383 static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
384 {
385 	skb->encapsulation = 1;
386 	skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
387 	return inet_gro_complete(skb, nhoff);
388 }
389 
390 
391 static struct sk_buff *sit_gso_segment(struct sk_buff *skb,
392 				       netdev_features_t features)
393 {
394 	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
395 		return ERR_PTR(-EINVAL);
396 
397 	return ipv6_gso_segment(skb, features);
398 }
399 
400 static struct sk_buff *ip4ip6_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 inet_gso_segment(skb, features);
407 }
408 
409 static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb,
410 					  netdev_features_t features)
411 {
412 	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
413 		return ERR_PTR(-EINVAL);
414 
415 	return ipv6_gso_segment(skb, features);
416 }
417 
418 static const struct net_offload sit_offload = {
419 	.callbacks = {
420 		.gso_segment	= sit_gso_segment,
421 		.gro_receive    = sit_ip6ip6_gro_receive,
422 		.gro_complete   = sit_gro_complete,
423 	},
424 };
425 
426 static const struct net_offload ip4ip6_offload = {
427 	.callbacks = {
428 		.gso_segment	= ip4ip6_gso_segment,
429 		.gro_receive    = ip4ip6_gro_receive,
430 		.gro_complete   = ip4ip6_gro_complete,
431 	},
432 };
433 
434 static const struct net_offload ip6ip6_offload = {
435 	.callbacks = {
436 		.gso_segment	= ip6ip6_gso_segment,
437 		.gro_receive    = sit_ip6ip6_gro_receive,
438 		.gro_complete   = ip6ip6_gro_complete,
439 	},
440 };
441 static int __init ipv6_offload_init(void)
442 {
443 
444 	if (tcpv6_offload_init() < 0)
445 		pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
446 	if (ipv6_exthdrs_offload_init() < 0)
447 		pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
448 
449 	net_hotdata.ipv6_packet_offload = (struct packet_offload) {
450 		.type = cpu_to_be16(ETH_P_IPV6),
451 		.callbacks = {
452 			.gso_segment = ipv6_gso_segment,
453 			.gro_receive = ipv6_gro_receive,
454 			.gro_complete = ipv6_gro_complete,
455 		},
456 	};
457 	dev_add_offload(&net_hotdata.ipv6_packet_offload);
458 
459 	inet_add_offload(&sit_offload, IPPROTO_IPV6);
460 	inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
461 	inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
462 
463 	return 0;
464 }
465 
466 fs_initcall(ipv6_offload_init);
467