1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *	IPV4 GSO/GRO offload support
  4 *	Linux INET implementation
  5 *
  6 *	UDPv4 GSO support
  7 */
  8
  9#include <linux/skbuff.h>
 10#include <net/udp.h>
 11#include <net/protocol.h>
 12#include <net/inet_common.h>
 13
 14static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
 15	netdev_features_t features,
 16	struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
 17					     netdev_features_t features),
 18	__be16 new_protocol, bool is_ipv6)
 19{
 20	int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
 21	bool remcsum, need_csum, offload_csum, gso_partial;
 22	struct sk_buff *segs = ERR_PTR(-EINVAL);
 23	struct udphdr *uh = udp_hdr(skb);
 24	u16 mac_offset = skb->mac_header;
 25	__be16 protocol = skb->protocol;
 26	u16 mac_len = skb->mac_len;
 27	int udp_offset, outer_hlen;
 28	__wsum partial;
 29	bool need_ipsec;
 30
 31	if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
 32		goto out;
 33
 34	/* Adjust partial header checksum to negate old length.
 35	 * We cannot rely on the value contained in uh->len as it is
 36	 * possible that the actual value exceeds the boundaries of the
 37	 * 16 bit length field due to the header being added outside of an
 38	 * IP or IPv6 frame that was already limited to 64K - 1.
 39	 */
 40	if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
 41		partial = (__force __wsum)uh->len;
 42	else
 43		partial = (__force __wsum)htonl(skb->len);
 44	partial = csum_sub(csum_unfold(uh->check), partial);
 45
 46	/* setup inner skb. */
 47	skb->encapsulation = 0;
 48	SKB_GSO_CB(skb)->encap_level = 0;
 49	__skb_pull(skb, tnl_hlen);
 50	skb_reset_mac_header(skb);
 51	skb_set_network_header(skb, skb_inner_network_offset(skb));
 52	skb_set_transport_header(skb, skb_inner_transport_offset(skb));
 53	skb->mac_len = skb_inner_network_offset(skb);
 54	skb->protocol = new_protocol;
 55
 56	need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
 57	skb->encap_hdr_csum = need_csum;
 58
 59	remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
 60	skb->remcsum_offload = remcsum;
 61
 62	need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb));
 63	/* Try to offload checksum if possible */
 64	offload_csum = !!(need_csum &&
 65			  !need_ipsec &&
 66			  (skb->dev->features &
 67			   (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
 68				      (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
 69
 70	features &= skb->dev->hw_enc_features;
 71	if (need_csum)
 72		features &= ~NETIF_F_SCTP_CRC;
 73
 74	/* The only checksum offload we care about from here on out is the
 75	 * outer one so strip the existing checksum feature flags and
 76	 * instead set the flag based on our outer checksum offload value.
 77	 */
 78	if (remcsum) {
 79		features &= ~NETIF_F_CSUM_MASK;
 80		if (!need_csum || offload_csum)
 81			features |= NETIF_F_HW_CSUM;
 82	}
 83
 84	/* segment inner packet. */
 85	segs = gso_inner_segment(skb, features);
 86	if (IS_ERR_OR_NULL(segs)) {
 87		skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
 88				     mac_len);
 89		goto out;
 90	}
 91
 92	gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
 93
 94	outer_hlen = skb_tnl_header_len(skb);
 95	udp_offset = outer_hlen - tnl_hlen;
 96	skb = segs;
 97	do {
 98		unsigned int len;
 99
100		if (remcsum)
101			skb->ip_summed = CHECKSUM_NONE;
102
103		/* Set up inner headers if we are offloading inner checksum */
104		if (skb->ip_summed == CHECKSUM_PARTIAL) {
105			skb_reset_inner_headers(skb);
106			skb->encapsulation = 1;
107		}
108
109		skb->mac_len = mac_len;
110		skb->protocol = protocol;
111
112		__skb_push(skb, outer_hlen);
113		skb_reset_mac_header(skb);
114		skb_set_network_header(skb, mac_len);
115		skb_set_transport_header(skb, udp_offset);
116		len = skb->len - udp_offset;
117		uh = udp_hdr(skb);
118
119		/* If we are only performing partial GSO the inner header
120		 * will be using a length value equal to only one MSS sized
121		 * segment instead of the entire frame.
122		 */
123		if (gso_partial && skb_is_gso(skb)) {
124			uh->len = htons(skb_shinfo(skb)->gso_size +
125					SKB_GSO_CB(skb)->data_offset +
126					skb->head - (unsigned char *)uh);
127		} else {
128			uh->len = htons(len);
129		}
130
131		if (!need_csum)
132			continue;
133
134		uh->check = ~csum_fold(csum_add(partial,
135				       (__force __wsum)htonl(len)));
136
137		if (skb->encapsulation || !offload_csum) {
138			uh->check = gso_make_checksum(skb, ~uh->check);
139			if (uh->check == 0)
140				uh->check = CSUM_MANGLED_0;
141		} else {
142			skb->ip_summed = CHECKSUM_PARTIAL;
143			skb->csum_start = skb_transport_header(skb) - skb->head;
144			skb->csum_offset = offsetof(struct udphdr, check);
145		}
146	} while ((skb = skb->next));
147out:
148	return segs;
149}
150
151struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
152				       netdev_features_t features,
153				       bool is_ipv6)
154{
155	__be16 protocol = skb->protocol;
156	const struct net_offload **offloads;
157	const struct net_offload *ops;
158	struct sk_buff *segs = ERR_PTR(-EINVAL);
159	struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
160					     netdev_features_t features);
161
162	rcu_read_lock();
163
164	switch (skb->inner_protocol_type) {
165	case ENCAP_TYPE_ETHER:
166		protocol = skb->inner_protocol;
167		gso_inner_segment = skb_mac_gso_segment;
168		break;
169	case ENCAP_TYPE_IPPROTO:
170		offloads = is_ipv6 ? inet6_offloads : inet_offloads;
171		ops = rcu_dereference(offloads[skb->inner_ipproto]);
172		if (!ops || !ops->callbacks.gso_segment)
173			goto out_unlock;
174		gso_inner_segment = ops->callbacks.gso_segment;
175		break;
176	default:
177		goto out_unlock;
178	}
179
180	segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
181					protocol, is_ipv6);
182
183out_unlock:
184	rcu_read_unlock();
185
186	return segs;
187}
188EXPORT_SYMBOL(skb_udp_tunnel_segment);
189
190static void __udpv4_gso_segment_csum(struct sk_buff *seg,
191				     __be32 *oldip, __be32 *newip,
192				     __be16 *oldport, __be16 *newport)
193{
194	struct udphdr *uh;
195	struct iphdr *iph;
196
197	if (*oldip == *newip && *oldport == *newport)
198		return;
199
200	uh = udp_hdr(seg);
201	iph = ip_hdr(seg);
202
203	if (uh->check) {
204		inet_proto_csum_replace4(&uh->check, seg, *oldip, *newip,
205					 true);
206		inet_proto_csum_replace2(&uh->check, seg, *oldport, *newport,
207					 false);
208		if (!uh->check)
209			uh->check = CSUM_MANGLED_0;
210	}
211	*oldport = *newport;
212
213	csum_replace4(&iph->check, *oldip, *newip);
214	*oldip = *newip;
215}
216
217static struct sk_buff *__udpv4_gso_segment_list_csum(struct sk_buff *segs)
218{
219	struct sk_buff *seg;
220	struct udphdr *uh, *uh2;
221	struct iphdr *iph, *iph2;
222
223	seg = segs;
224	uh = udp_hdr(seg);
225	iph = ip_hdr(seg);
226
227	if ((udp_hdr(seg)->dest == udp_hdr(seg->next)->dest) &&
228	    (udp_hdr(seg)->source == udp_hdr(seg->next)->source) &&
229	    (ip_hdr(seg)->daddr == ip_hdr(seg->next)->daddr) &&
230	    (ip_hdr(seg)->saddr == ip_hdr(seg->next)->saddr))
231		return segs;
232
233	while ((seg = seg->next)) {
234		uh2 = udp_hdr(seg);
235		iph2 = ip_hdr(seg);
236
237		__udpv4_gso_segment_csum(seg,
238					 &iph2->saddr, &iph->saddr,
239					 &uh2->source, &uh->source);
240		__udpv4_gso_segment_csum(seg,
241					 &iph2->daddr, &iph->daddr,
242					 &uh2->dest, &uh->dest);
243	}
244
245	return segs;
246}
247
248static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
249					      netdev_features_t features,
250					      bool is_ipv6)
251{
252	unsigned int mss = skb_shinfo(skb)->gso_size;
253
254	skb = skb_segment_list(skb, features, skb_mac_header_len(skb));
255	if (IS_ERR(skb))
256		return skb;
257
258	udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss);
259
260	return is_ipv6 ? skb : __udpv4_gso_segment_list_csum(skb);
261}
262
263struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
264				  netdev_features_t features, bool is_ipv6)
265{
266	struct sock *sk = gso_skb->sk;
267	unsigned int sum_truesize = 0;
268	struct sk_buff *segs, *seg;
269	struct udphdr *uh;
270	unsigned int mss;
271	bool copy_dtor;
272	__sum16 check;
273	__be16 newlen;
274
275	if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)
276		return __udp_gso_segment_list(gso_skb, features, is_ipv6);
277
278	mss = skb_shinfo(gso_skb)->gso_size;
279	if (gso_skb->len <= sizeof(*uh) + mss)
280		return ERR_PTR(-EINVAL);
281
282	skb_pull(gso_skb, sizeof(*uh));
283
284	/* clear destructor to avoid skb_segment assigning it to tail */
285	copy_dtor = gso_skb->destructor == sock_wfree;
286	if (copy_dtor)
287		gso_skb->destructor = NULL;
288
289	segs = skb_segment(gso_skb, features);
290	if (IS_ERR_OR_NULL(segs)) {
291		if (copy_dtor)
292			gso_skb->destructor = sock_wfree;
293		return segs;
294	}
295
296	/* GSO partial and frag_list segmentation only requires splitting
297	 * the frame into an MSS multiple and possibly a remainder, both
298	 * cases return a GSO skb. So update the mss now.
299	 */
300	if (skb_is_gso(segs))
301		mss *= skb_shinfo(segs)->gso_segs;
302
303	seg = segs;
304	uh = udp_hdr(seg);
305
306	/* preserve TX timestamp flags and TS key for first segment */
307	skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey;
308	skb_shinfo(seg)->tx_flags |=
309			(skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP);
310
311	/* compute checksum adjustment based on old length versus new */
312	newlen = htons(sizeof(*uh) + mss);
313	check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
314
315	for (;;) {
316		if (copy_dtor) {
317			seg->destructor = sock_wfree;
318			seg->sk = sk;
319			sum_truesize += seg->truesize;
320		}
321
322		if (!seg->next)
323			break;
324
325		uh->len = newlen;
326		uh->check = check;
327
328		if (seg->ip_summed == CHECKSUM_PARTIAL)
329			gso_reset_checksum(seg, ~check);
330		else
331			uh->check = gso_make_checksum(seg, ~check) ? :
332				    CSUM_MANGLED_0;
333
334		seg = seg->next;
335		uh = udp_hdr(seg);
336	}
337
338	/* last packet can be partial gso_size, account for that in checksum */
339	newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
340		       seg->data_len);
341	check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
342
343	uh->len = newlen;
344	uh->check = check;
345
346	if (seg->ip_summed == CHECKSUM_PARTIAL)
347		gso_reset_checksum(seg, ~check);
348	else
349		uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
350
351	/* update refcount for the packet */
352	if (copy_dtor) {
353		int delta = sum_truesize - gso_skb->truesize;
354
355		/* In some pathological cases, delta can be negative.
356		 * We need to either use refcount_add() or refcount_sub_and_test()
357		 */
358		if (likely(delta >= 0))
359			refcount_add(delta, &sk->sk_wmem_alloc);
360		else
361			WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
362	}
363	return segs;
364}
365EXPORT_SYMBOL_GPL(__udp_gso_segment);
366
367static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
368					 netdev_features_t features)
369{
370	struct sk_buff *segs = ERR_PTR(-EINVAL);
371	unsigned int mss;
372	__wsum csum;
373	struct udphdr *uh;
374	struct iphdr *iph;
375
376	if (skb->encapsulation &&
377	    (skb_shinfo(skb)->gso_type &
378	     (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
379		segs = skb_udp_tunnel_segment(skb, features, false);
380		goto out;
381	}
382
383	if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
384		goto out;
385
386	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
387		goto out;
388
389	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
390		return __udp_gso_segment(skb, features, false);
391
392	mss = skb_shinfo(skb)->gso_size;
393	if (unlikely(skb->len <= mss))
394		goto out;
395
396	/* Do software UFO. Complete and fill in the UDP checksum as
397	 * HW cannot do checksum of UDP packets sent as multiple
398	 * IP fragments.
399	 */
400
401	uh = udp_hdr(skb);
402	iph = ip_hdr(skb);
403
404	uh->check = 0;
405	csum = skb_checksum(skb, 0, skb->len, 0);
406	uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
407	if (uh->check == 0)
408		uh->check = CSUM_MANGLED_0;
409
410	skb->ip_summed = CHECKSUM_UNNECESSARY;
411
412	/* If there is no outer header we can fake a checksum offload
413	 * due to the fact that we have already done the checksum in
414	 * software prior to segmenting the frame.
415	 */
416	if (!skb->encap_hdr_csum)
417		features |= NETIF_F_HW_CSUM;
418
419	/* Fragment the skb. IP headers of the fragments are updated in
420	 * inet_gso_segment()
421	 */
422	segs = skb_segment(skb, features);
423out:
424	return segs;
425}
426
427#define UDP_GRO_CNT_MAX 64
428static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
429					       struct sk_buff *skb)
430{
431	struct udphdr *uh = udp_gro_udphdr(skb);
432	struct sk_buff *pp = NULL;
433	struct udphdr *uh2;
434	struct sk_buff *p;
435	unsigned int ulen;
436	int ret = 0;
437
438	/* requires non zero csum, for symmetry with GSO */
439	if (!uh->check) {
440		NAPI_GRO_CB(skb)->flush = 1;
441		return NULL;
442	}
443
444	/* Do not deal with padded or malicious packets, sorry ! */
445	ulen = ntohs(uh->len);
446	if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) {
447		NAPI_GRO_CB(skb)->flush = 1;
448		return NULL;
449	}
450	/* pull encapsulating udp header */
451	skb_gro_pull(skb, sizeof(struct udphdr));
452
453	list_for_each_entry(p, head, list) {
454		if (!NAPI_GRO_CB(p)->same_flow)
455			continue;
456
457		uh2 = udp_hdr(p);
458
459		/* Match ports only, as csum is always non zero */
460		if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
461			NAPI_GRO_CB(p)->same_flow = 0;
462			continue;
463		}
464
465		if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) {
466			NAPI_GRO_CB(skb)->flush = 1;
467			return p;
468		}
469
470		/* Terminate the flow on len mismatch or if it grow "too much".
471		 * Under small packet flood GRO count could elsewhere grow a lot
472		 * leading to excessive truesize values.
473		 * On len mismatch merge the first packet shorter than gso_size,
474		 * otherwise complete the GRO packet.
475		 */
476		if (ulen > ntohs(uh2->len)) {
477			pp = p;
478		} else {
479			if (NAPI_GRO_CB(skb)->is_flist) {
480				if (!pskb_may_pull(skb, skb_gro_offset(skb))) {
481					NAPI_GRO_CB(skb)->flush = 1;
482					return NULL;
483				}
484				if ((skb->ip_summed != p->ip_summed) ||
485				    (skb->csum_level != p->csum_level)) {
486					NAPI_GRO_CB(skb)->flush = 1;
487					return NULL;
488				}
489				ret = skb_gro_receive_list(p, skb);
490			} else {
491				skb_gro_postpull_rcsum(skb, uh,
492						       sizeof(struct udphdr));
493
494				ret = skb_gro_receive(p, skb);
495			}
496		}
497
498		if (ret || ulen != ntohs(uh2->len) ||
499		    NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
500			pp = p;
501
502		return pp;
503	}
504
505	/* mismatch, but we never need to flush */
506	return NULL;
507}
508
509struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
510				struct udphdr *uh, struct sock *sk)
511{
512	struct sk_buff *pp = NULL;
513	struct sk_buff *p;
514	struct udphdr *uh2;
515	unsigned int off = skb_gro_offset(skb);
516	int flush = 1;
517
518	/* we can do L4 aggregation only if the packet can't land in a tunnel
519	 * otherwise we could corrupt the inner stream
520	 */
521	NAPI_GRO_CB(skb)->is_flist = 0;
522	if (!sk || !udp_sk(sk)->gro_receive) {
523		if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
524			NAPI_GRO_CB(skb)->is_flist = sk ? !udp_sk(sk)->gro_enabled : 1;
525
526		if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
527		    (sk && udp_sk(sk)->gro_enabled) || NAPI_GRO_CB(skb)->is_flist)
528			return call_gro_receive(udp_gro_receive_segment, head, skb);
529
530		/* no GRO, be sure flush the current packet */
531		goto out;
 
532	}
533
534	if (NAPI_GRO_CB(skb)->encap_mark ||
535	    (uh->check && skb->ip_summed != CHECKSUM_PARTIAL &&
536	     NAPI_GRO_CB(skb)->csum_cnt == 0 &&
537	     !NAPI_GRO_CB(skb)->csum_valid))
 
538		goto out;
539
540	/* mark that this skb passed once through the tunnel gro layer */
541	NAPI_GRO_CB(skb)->encap_mark = 1;
542
543	flush = 0;
544
545	list_for_each_entry(p, head, list) {
546		if (!NAPI_GRO_CB(p)->same_flow)
547			continue;
548
549		uh2 = (struct udphdr   *)(p->data + off);
550
551		/* Match ports and either checksums are either both zero
552		 * or nonzero.
553		 */
554		if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
555		    (!uh->check ^ !uh2->check)) {
556			NAPI_GRO_CB(p)->same_flow = 0;
557			continue;
558		}
559	}
560
561	skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
562	skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
563	pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
564
565out:
566	skb_gro_flush_final(skb, pp, flush);
567	return pp;
568}
569EXPORT_SYMBOL(udp_gro_receive);
570
571static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport,
572					__be16 dport)
573{
574	const struct iphdr *iph = skb_gro_network_header(skb);
575
576	return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
577				 iph->daddr, dport, inet_iif(skb),
578				 inet_sdif(skb), &udp_table, NULL);
579}
580
581INDIRECT_CALLABLE_SCOPE
582struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
583{
584	struct udphdr *uh = udp_gro_udphdr(skb);
585	struct sock *sk = NULL;
586	struct sk_buff *pp;
 
587
588	if (unlikely(!uh))
589		goto flush;
590
591	/* Don't bother verifying checksum if we're going to flush anyway. */
592	if (NAPI_GRO_CB(skb)->flush)
593		goto skip;
594
595	if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
596						 inet_gro_compute_pseudo))
597		goto flush;
598	else if (uh->check)
599		skb_gro_checksum_try_convert(skb, IPPROTO_UDP,
600					     inet_gro_compute_pseudo);
601skip:
602	NAPI_GRO_CB(skb)->is_ipv6 = 0;
603	rcu_read_lock();
604
605	if (static_branch_unlikely(&udp_encap_needed_key))
606		sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest);
607
608	pp = udp_gro_receive(head, skb, uh, sk);
609	rcu_read_unlock();
610	return pp;
611
612flush:
613	NAPI_GRO_CB(skb)->flush = 1;
614	return NULL;
615}
616
617static int udp_gro_complete_segment(struct sk_buff *skb)
618{
619	struct udphdr *uh = udp_hdr(skb);
620
621	skb->csum_start = (unsigned char *)uh - skb->head;
622	skb->csum_offset = offsetof(struct udphdr, check);
623	skb->ip_summed = CHECKSUM_PARTIAL;
624
625	skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
626	skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
627
628	if (skb->encapsulation)
629		skb->inner_transport_header = skb->transport_header;
630
631	return 0;
632}
633
634int udp_gro_complete(struct sk_buff *skb, int nhoff,
635		     udp_lookup_t lookup)
636{
637	__be16 newlen = htons(skb->len - nhoff);
638	struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
 
639	struct sock *sk;
640	int err;
641
642	uh->len = newlen;
643
644	rcu_read_lock();
645	sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
646				udp4_lib_lookup_skb, skb, uh->source, uh->dest);
647	if (sk && udp_sk(sk)->gro_complete) {
648		skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
649					: SKB_GSO_UDP_TUNNEL;
650
651		/* clear the encap mark, so that inner frag_list gro_complete
652		 * can take place
653		 */
654		NAPI_GRO_CB(skb)->encap_mark = 0;
655
656		/* Set encapsulation before calling into inner gro_complete()
657		 * functions to make them set up the inner offsets.
658		 */
659		skb->encapsulation = 1;
660		err = udp_sk(sk)->gro_complete(sk, skb,
661				nhoff + sizeof(struct udphdr));
662	} else {
663		err = udp_gro_complete_segment(skb);
664	}
665	rcu_read_unlock();
666
667	if (skb->remcsum_offload)
668		skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
669
670	return err;
671}
672EXPORT_SYMBOL(udp_gro_complete);
673
674INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
675{
676	const struct iphdr *iph = ip_hdr(skb);
677	struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
678
679	/* do fraglist only if there is no outer UDP encap (or we already processed it) */
680	if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) {
681		uh->len = htons(skb->len - nhoff);
682
683		skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
684		skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
685
686		if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
687			if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
688				skb->csum_level++;
689		} else {
690			skb->ip_summed = CHECKSUM_UNNECESSARY;
691			skb->csum_level = 0;
692		}
693
694		return 0;
695	}
696
697	if (uh->check)
698		uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
699					  iph->daddr, 0);
700
701	return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
702}
703
704static const struct net_offload udpv4_offload = {
705	.callbacks = {
706		.gso_segment = udp4_ufo_fragment,
707		.gro_receive  =	udp4_gro_receive,
708		.gro_complete =	udp4_gro_complete,
709	},
710};
711
712int __init udpv4_offload_init(void)
713{
714	return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
715}