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/gro.h>
 11#include <net/gso.h>
 12#include <net/udp.h>
 13#include <net/protocol.h>
 14#include <net/inet_common.h>
 15
 16static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
 17	netdev_features_t features,
 18	struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
 19					     netdev_features_t features),
 20	__be16 new_protocol, bool is_ipv6)
 21{
 22	int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
 23	bool remcsum, need_csum, offload_csum, gso_partial;
 24	struct sk_buff *segs = ERR_PTR(-EINVAL);
 25	struct udphdr *uh = udp_hdr(skb);
 26	u16 mac_offset = skb->mac_header;
 27	__be16 protocol = skb->protocol;
 28	u16 mac_len = skb->mac_len;
 29	int udp_offset, outer_hlen;
 30	__wsum partial;
 31	bool need_ipsec;
 32
 33	if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
 34		goto out;
 35
 36	/* Adjust partial header checksum to negate old length.
 37	 * We cannot rely on the value contained in uh->len as it is
 38	 * possible that the actual value exceeds the boundaries of the
 39	 * 16 bit length field due to the header being added outside of an
 40	 * IP or IPv6 frame that was already limited to 64K - 1.
 41	 */
 42	if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
 43		partial = (__force __wsum)uh->len;
 44	else
 45		partial = (__force __wsum)htonl(skb->len);
 46	partial = csum_sub(csum_unfold(uh->check), partial);
 47
 48	/* setup inner skb. */
 49	skb->encapsulation = 0;
 50	SKB_GSO_CB(skb)->encap_level = 0;
 51	__skb_pull(skb, tnl_hlen);
 52	skb_reset_mac_header(skb);
 53	skb_set_network_header(skb, skb_inner_network_offset(skb));
 54	skb_set_transport_header(skb, skb_inner_transport_offset(skb));
 55	skb->mac_len = skb_inner_network_offset(skb);
 56	skb->protocol = new_protocol;
 57
 58	need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
 59	skb->encap_hdr_csum = need_csum;
 60
 61	remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
 62	skb->remcsum_offload = remcsum;
 63
 64	need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb));
 65	/* Try to offload checksum if possible */
 66	offload_csum = !!(need_csum &&
 67			  !need_ipsec &&
 68			  (skb->dev->features &
 69			   (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
 70				      (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
 71
 72	features &= skb->dev->hw_enc_features;
 73	if (need_csum)
 74		features &= ~NETIF_F_SCTP_CRC;
 75
 76	/* The only checksum offload we care about from here on out is the
 77	 * outer one so strip the existing checksum feature flags and
 78	 * instead set the flag based on our outer checksum offload value.
 79	 */
 80	if (remcsum) {
 81		features &= ~NETIF_F_CSUM_MASK;
 82		if (!need_csum || offload_csum)
 83			features |= NETIF_F_HW_CSUM;
 84	}
 85
 86	/* segment inner packet. */
 87	segs = gso_inner_segment(skb, features);
 88	if (IS_ERR_OR_NULL(segs)) {
 89		skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
 90				     mac_len);
 91		goto out;
 92	}
 93
 94	gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
 95
 96	outer_hlen = skb_tnl_header_len(skb);
 97	udp_offset = outer_hlen - tnl_hlen;
 98	skb = segs;
 99	do {
100		unsigned int len;
101
102		if (remcsum)
103			skb->ip_summed = CHECKSUM_NONE;
104
105		/* Set up inner headers if we are offloading inner checksum */
106		if (skb->ip_summed == CHECKSUM_PARTIAL) {
107			skb_reset_inner_headers(skb);
108			skb->encapsulation = 1;
109		}
110
111		skb->mac_len = mac_len;
112		skb->protocol = protocol;
113
114		__skb_push(skb, outer_hlen);
115		skb_reset_mac_header(skb);
116		skb_set_network_header(skb, mac_len);
117		skb_set_transport_header(skb, udp_offset);
118		len = skb->len - udp_offset;
119		uh = udp_hdr(skb);
120
121		/* If we are only performing partial GSO the inner header
122		 * will be using a length value equal to only one MSS sized
123		 * segment instead of the entire frame.
124		 */
125		if (gso_partial && skb_is_gso(skb)) {
126			uh->len = htons(skb_shinfo(skb)->gso_size +
127					SKB_GSO_CB(skb)->data_offset +
128					skb->head - (unsigned char *)uh);
129		} else {
130			uh->len = htons(len);
131		}
132
133		if (!need_csum)
134			continue;
135
136		uh->check = ~csum_fold(csum_add(partial,
137				       (__force __wsum)htonl(len)));
138
139		if (skb->encapsulation || !offload_csum) {
140			uh->check = gso_make_checksum(skb, ~uh->check);
141			if (uh->check == 0)
142				uh->check = CSUM_MANGLED_0;
143		} else {
144			skb->ip_summed = CHECKSUM_PARTIAL;
145			skb->csum_start = skb_transport_header(skb) - skb->head;
146			skb->csum_offset = offsetof(struct udphdr, check);
147		}
148	} while ((skb = skb->next));
149out:
150	return segs;
151}
152
153struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
154				       netdev_features_t features,
155				       bool is_ipv6)
156{
157	const struct net_offload __rcu **offloads;
158	__be16 protocol = skb->protocol;
159	const struct net_offload *ops;
160	struct sk_buff *segs = ERR_PTR(-EINVAL);
161	struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
162					     netdev_features_t features);
163
164	rcu_read_lock();
165
166	switch (skb->inner_protocol_type) {
167	case ENCAP_TYPE_ETHER:
168		protocol = skb->inner_protocol;
169		gso_inner_segment = skb_mac_gso_segment;
170		break;
171	case ENCAP_TYPE_IPPROTO:
172		offloads = is_ipv6 ? inet6_offloads : inet_offloads;
173		ops = rcu_dereference(offloads[skb->inner_ipproto]);
174		if (!ops || !ops->callbacks.gso_segment)
175			goto out_unlock;
176		gso_inner_segment = ops->callbacks.gso_segment;
177		break;
178	default:
179		goto out_unlock;
180	}
181
182	segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
183					protocol, is_ipv6);
184
185out_unlock:
186	rcu_read_unlock();
187
188	return segs;
189}
190EXPORT_SYMBOL(skb_udp_tunnel_segment);
191
192static void __udpv4_gso_segment_csum(struct sk_buff *seg,
193				     __be32 *oldip, __be32 *newip,
194				     __be16 *oldport, __be16 *newport)
195{
196	struct udphdr *uh;
197	struct iphdr *iph;
198
199	if (*oldip == *newip && *oldport == *newport)
200		return;
201
202	uh = udp_hdr(seg);
203	iph = ip_hdr(seg);
204
205	if (uh->check) {
206		inet_proto_csum_replace4(&uh->check, seg, *oldip, *newip,
207					 true);
208		inet_proto_csum_replace2(&uh->check, seg, *oldport, *newport,
209					 false);
210		if (!uh->check)
211			uh->check = CSUM_MANGLED_0;
212	}
213	*oldport = *newport;
214
215	csum_replace4(&iph->check, *oldip, *newip);
216	*oldip = *newip;
217}
218
219static struct sk_buff *__udpv4_gso_segment_list_csum(struct sk_buff *segs)
220{
221	struct sk_buff *seg;
222	struct udphdr *uh, *uh2;
223	struct iphdr *iph, *iph2;
224
225	seg = segs;
226	uh = udp_hdr(seg);
227	iph = ip_hdr(seg);
228
229	if ((udp_hdr(seg)->dest == udp_hdr(seg->next)->dest) &&
230	    (udp_hdr(seg)->source == udp_hdr(seg->next)->source) &&
231	    (ip_hdr(seg)->daddr == ip_hdr(seg->next)->daddr) &&
232	    (ip_hdr(seg)->saddr == ip_hdr(seg->next)->saddr))
233		return segs;
234
235	while ((seg = seg->next)) {
236		uh2 = udp_hdr(seg);
237		iph2 = ip_hdr(seg);
238
239		__udpv4_gso_segment_csum(seg,
240					 &iph2->saddr, &iph->saddr,
241					 &uh2->source, &uh->source);
242		__udpv4_gso_segment_csum(seg,
243					 &iph2->daddr, &iph->daddr,
244					 &uh2->dest, &uh->dest);
245	}
246
247	return segs;
248}
249
250static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
251					      netdev_features_t features,
252					      bool is_ipv6)
253{
254	unsigned int mss = skb_shinfo(skb)->gso_size;
255
256	skb = skb_segment_list(skb, features, skb_mac_header_len(skb));
257	if (IS_ERR(skb))
258		return skb;
259
260	udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss);
261
262	return is_ipv6 ? skb : __udpv4_gso_segment_list_csum(skb);
263}
264
265struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
266				  netdev_features_t features, bool is_ipv6)
267{
268	struct sock *sk = gso_skb->sk;
269	unsigned int sum_truesize = 0;
270	struct sk_buff *segs, *seg;
271	struct udphdr *uh;
272	unsigned int mss;
273	bool copy_dtor;
274	__sum16 check;
275	__be16 newlen;
276
277	mss = skb_shinfo(gso_skb)->gso_size;
278	if (gso_skb->len <= sizeof(*uh) + mss)
279		return ERR_PTR(-EINVAL);
280
281	if (unlikely(skb_checksum_start(gso_skb) !=
282		     skb_transport_header(gso_skb) &&
283		     !(skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)))
284		return ERR_PTR(-EINVAL);
285
286	/* We don't know if egress device can segment and checksum the packet
287	 * when IPv6 extension headers are present. Fall back to software GSO.
288	 */
289	if (gso_skb->ip_summed != CHECKSUM_PARTIAL)
290		features &= ~(NETIF_F_GSO_UDP_L4 | NETIF_F_CSUM_MASK);
291
292	if (skb_gso_ok(gso_skb, features | NETIF_F_GSO_ROBUST)) {
293		/* Packet is from an untrusted source, reset gso_segs. */
294		skb_shinfo(gso_skb)->gso_segs = DIV_ROUND_UP(gso_skb->len - sizeof(*uh),
295							     mss);
296		return NULL;
297	}
298
299	if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST) {
300		 /* Detect modified geometry and pass those to skb_segment. */
301		if (skb_pagelen(gso_skb) - sizeof(*uh) == skb_shinfo(gso_skb)->gso_size)
302			return __udp_gso_segment_list(gso_skb, features, is_ipv6);
303
304		 /* Setup csum, as fraglist skips this in udp4_gro_receive. */
305		gso_skb->csum_start = skb_transport_header(gso_skb) - gso_skb->head;
306		gso_skb->csum_offset = offsetof(struct udphdr, check);
307		gso_skb->ip_summed = CHECKSUM_PARTIAL;
308
309		uh = udp_hdr(gso_skb);
310		if (is_ipv6)
311			uh->check = ~udp_v6_check(gso_skb->len,
312						  &ipv6_hdr(gso_skb)->saddr,
313						  &ipv6_hdr(gso_skb)->daddr, 0);
314		else
315			uh->check = ~udp_v4_check(gso_skb->len,
316						  ip_hdr(gso_skb)->saddr,
317						  ip_hdr(gso_skb)->daddr, 0);
318	}
319
320	skb_pull(gso_skb, sizeof(*uh));
321
322	/* clear destructor to avoid skb_segment assigning it to tail */
323	copy_dtor = gso_skb->destructor == sock_wfree;
324	if (copy_dtor) {
325		gso_skb->destructor = NULL;
326		gso_skb->sk = NULL;
327	}
328
329	segs = skb_segment(gso_skb, features);
330	if (IS_ERR_OR_NULL(segs)) {
331		if (copy_dtor) {
332			gso_skb->destructor = sock_wfree;
333			gso_skb->sk = sk;
334		}
335		return segs;
336	}
337
338	/* GSO partial and frag_list segmentation only requires splitting
339	 * the frame into an MSS multiple and possibly a remainder, both
340	 * cases return a GSO skb. So update the mss now.
341	 */
342	if (skb_is_gso(segs))
343		mss *= skb_shinfo(segs)->gso_segs;
344
345	seg = segs;
346	uh = udp_hdr(seg);
347
348	/* preserve TX timestamp flags and TS key for first segment */
349	skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey;
350	skb_shinfo(seg)->tx_flags |=
351			(skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP);
352
353	/* compute checksum adjustment based on old length versus new */
354	newlen = htons(sizeof(*uh) + mss);
355	check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
356
357	for (;;) {
358		if (copy_dtor) {
359			seg->destructor = sock_wfree;
360			seg->sk = sk;
361			sum_truesize += seg->truesize;
362		}
363
364		if (!seg->next)
365			break;
366
367		uh->len = newlen;
368		uh->check = check;
369
370		if (seg->ip_summed == CHECKSUM_PARTIAL)
371			gso_reset_checksum(seg, ~check);
372		else
373			uh->check = gso_make_checksum(seg, ~check) ? :
374				    CSUM_MANGLED_0;
375
376		seg = seg->next;
377		uh = udp_hdr(seg);
378	}
379
380	/* last packet can be partial gso_size, account for that in checksum */
381	newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
382		       seg->data_len);
383	check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
384
385	uh->len = newlen;
386	uh->check = check;
387
388	if (seg->ip_summed == CHECKSUM_PARTIAL)
389		gso_reset_checksum(seg, ~check);
390	else
391		uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
392
393	/* On the TX path, CHECKSUM_NONE and CHECKSUM_UNNECESSARY have the same
394	 * meaning. However, check for bad offloads in the GSO stack expects the
395	 * latter, if the checksum was calculated in software. To vouch for the
396	 * segment skbs we actually need to set it on the gso_skb.
397	 */
398	if (gso_skb->ip_summed == CHECKSUM_NONE)
399		gso_skb->ip_summed = CHECKSUM_UNNECESSARY;
400
401	/* update refcount for the packet */
402	if (copy_dtor) {
403		int delta = sum_truesize - gso_skb->truesize;
404
405		/* In some pathological cases, delta can be negative.
406		 * We need to either use refcount_add() or refcount_sub_and_test()
407		 */
408		if (likely(delta >= 0))
409			refcount_add(delta, &sk->sk_wmem_alloc);
410		else
411			WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
412	}
413	return segs;
414}
415EXPORT_SYMBOL_GPL(__udp_gso_segment);
416
417static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
418					 netdev_features_t features)
419{
420	struct sk_buff *segs = ERR_PTR(-EINVAL);
421	unsigned int mss;
422	__wsum csum;
423	struct udphdr *uh;
424	struct iphdr *iph;
425
426	if (skb->encapsulation &&
427	    (skb_shinfo(skb)->gso_type &
428	     (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
429		segs = skb_udp_tunnel_segment(skb, features, false);
430		goto out;
431	}
432
433	if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
434		goto out;
435
436	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
437		goto out;
438
439	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
440		return __udp_gso_segment(skb, features, false);
441
442	mss = skb_shinfo(skb)->gso_size;
443	if (unlikely(skb->len <= mss))
444		goto out;
445
446	/* Do software UFO. Complete and fill in the UDP checksum as
447	 * HW cannot do checksum of UDP packets sent as multiple
448	 * IP fragments.
449	 */
450
451	uh = udp_hdr(skb);
452	iph = ip_hdr(skb);
453
454	uh->check = 0;
455	csum = skb_checksum(skb, 0, skb->len, 0);
456	uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
457	if (uh->check == 0)
458		uh->check = CSUM_MANGLED_0;
459
460	skb->ip_summed = CHECKSUM_UNNECESSARY;
461
462	/* If there is no outer header we can fake a checksum offload
463	 * due to the fact that we have already done the checksum in
464	 * software prior to segmenting the frame.
465	 */
466	if (!skb->encap_hdr_csum)
467		features |= NETIF_F_HW_CSUM;
468
469	/* Fragment the skb. IP headers of the fragments are updated in
470	 * inet_gso_segment()
471	 */
472	segs = skb_segment(skb, features);
473out:
474	return segs;
475}
476
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
477
478#define UDP_GRO_CNT_MAX 64
479static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
480					       struct sk_buff *skb)
481{
482	struct udphdr *uh = udp_gro_udphdr(skb);
483	struct sk_buff *pp = NULL;
484	struct udphdr *uh2;
485	struct sk_buff *p;
486	unsigned int ulen;
487	int ret = 0;
488	int flush;
489
490	/* requires non zero csum, for symmetry with GSO */
491	if (!uh->check) {
492		NAPI_GRO_CB(skb)->flush = 1;
493		return NULL;
494	}
495
496	/* Do not deal with padded or malicious packets, sorry ! */
497	ulen = ntohs(uh->len);
498	if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) {
499		NAPI_GRO_CB(skb)->flush = 1;
500		return NULL;
501	}
502	/* pull encapsulating udp header */
503	skb_gro_pull(skb, sizeof(struct udphdr));
504
505	list_for_each_entry(p, head, list) {
506		if (!NAPI_GRO_CB(p)->same_flow)
507			continue;
508
509		uh2 = udp_hdr(p);
510
511		/* Match ports only, as csum is always non zero */
512		if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
513			NAPI_GRO_CB(p)->same_flow = 0;
514			continue;
515		}
516
517		if (NAPI_GRO_CB(skb)->is_flist != NAPI_GRO_CB(p)->is_flist) {
518			NAPI_GRO_CB(skb)->flush = 1;
519			return p;
520		}
521
522		flush = gro_receive_network_flush(uh, uh2, p);
523
524		/* Terminate the flow on len mismatch or if it grow "too much".
525		 * Under small packet flood GRO count could elsewhere grow a lot
526		 * leading to excessive truesize values.
527		 * On len mismatch merge the first packet shorter than gso_size,
528		 * otherwise complete the GRO packet.
529		 */
530		if (ulen > ntohs(uh2->len) || flush) {
531			pp = p;
532		} else {
533			if (NAPI_GRO_CB(skb)->is_flist) {
534				if (!pskb_may_pull(skb, skb_gro_offset(skb))) {
535					NAPI_GRO_CB(skb)->flush = 1;
536					return NULL;
537				}
538				if ((skb->ip_summed != p->ip_summed) ||
539				    (skb->csum_level != p->csum_level)) {
540					NAPI_GRO_CB(skb)->flush = 1;
541					return NULL;
542				}
543				ret = skb_gro_receive_list(p, skb);
544			} else {
545				skb_gro_postpull_rcsum(skb, uh,
546						       sizeof(struct udphdr));
547
548				ret = skb_gro_receive(p, skb);
549			}
550		}
551
552		if (ret || ulen != ntohs(uh2->len) ||
553		    NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
554			pp = p;
555
556		return pp;
557	}
558
559	/* mismatch, but we never need to flush */
560	return NULL;
561}
562
563struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
564				struct udphdr *uh, struct sock *sk)
565{
566	struct sk_buff *pp = NULL;
567	struct sk_buff *p;
568	struct udphdr *uh2;
569	unsigned int off = skb_gro_offset(skb);
570	int flush = 1;
571
572	/* We can do L4 aggregation only if the packet can't land in a tunnel
573	 * otherwise we could corrupt the inner stream. Detecting such packets
574	 * cannot be foolproof and the aggregation might still happen in some
575	 * cases. Such packets should be caught in udp_unexpected_gso later.
576	 */
577	NAPI_GRO_CB(skb)->is_flist = 0;
578	if (!sk || !udp_sk(sk)->gro_receive) {
579		/* If the packet was locally encapsulated in a UDP tunnel that
580		 * wasn't detected above, do not GRO.
581		 */
582		if (skb->encapsulation)
583			goto out;
584
585		if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
586			NAPI_GRO_CB(skb)->is_flist = sk ? !udp_test_bit(GRO_ENABLED, sk) : 1;
587
588		if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
589		    (sk && udp_test_bit(GRO_ENABLED, sk)) || NAPI_GRO_CB(skb)->is_flist)
590			return call_gro_receive(udp_gro_receive_segment, head, skb);
591
592		/* no GRO, be sure flush the current packet */
593		goto out;
594	}
595
596	if (NAPI_GRO_CB(skb)->encap_mark ||
597	    (uh->check && skb->ip_summed != CHECKSUM_PARTIAL &&
598	     NAPI_GRO_CB(skb)->csum_cnt == 0 &&
599	     !NAPI_GRO_CB(skb)->csum_valid))
600		goto out;
601
602	/* mark that this skb passed once through the tunnel gro layer */
603	NAPI_GRO_CB(skb)->encap_mark = 1;
604
605	flush = 0;
606
607	list_for_each_entry(p, head, list) {
608		if (!NAPI_GRO_CB(p)->same_flow)
609			continue;
610
611		uh2 = (struct udphdr   *)(p->data + off);
612
613		/* Match ports and either checksums are either both zero
614		 * or nonzero.
615		 */
616		if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
617		    (!uh->check ^ !uh2->check)) {
618			NAPI_GRO_CB(p)->same_flow = 0;
619			continue;
620		}
621	}
622
623	skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
624	skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
625	pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
626
627out:
628	skb_gro_flush_final(skb, pp, flush);
629	return pp;
630}
631EXPORT_SYMBOL(udp_gro_receive);
632
633static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport,
634					__be16 dport)
635{
636	const struct iphdr *iph = skb_gro_network_header(skb);
637	struct net *net = dev_net(skb->dev);
638	int iif, sdif;
639
640	inet_get_iif_sdif(skb, &iif, &sdif);
641
642	return __udp4_lib_lookup(net, iph->saddr, sport,
643				 iph->daddr, dport, iif,
644				 sdif, net->ipv4.udp_table, NULL);
645}
646
647INDIRECT_CALLABLE_SCOPE
648struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
649{
650	struct udphdr *uh = udp_gro_udphdr(skb);
651	struct sock *sk = NULL;
652	struct sk_buff *pp;
653
654	if (unlikely(!uh))
655		goto flush;
656
657	/* Don't bother verifying checksum if we're going to flush anyway. */
658	if (NAPI_GRO_CB(skb)->flush)
659		goto skip;
660
661	if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
662						 inet_gro_compute_pseudo))
663		goto flush;
664	else if (uh->check)
665		skb_gro_checksum_try_convert(skb, IPPROTO_UDP,
666					     inet_gro_compute_pseudo);
667skip:
668	NAPI_GRO_CB(skb)->is_ipv6 = 0;
669
670	if (static_branch_unlikely(&udp_encap_needed_key))
671		sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest);
672
673	pp = udp_gro_receive(head, skb, uh, sk);
674	return pp;
675
676flush:
677	NAPI_GRO_CB(skb)->flush = 1;
678	return NULL;
679}
680
681static int udp_gro_complete_segment(struct sk_buff *skb)
682{
683	struct udphdr *uh = udp_hdr(skb);
684
685	skb->csum_start = (unsigned char *)uh - skb->head;
686	skb->csum_offset = offsetof(struct udphdr, check);
687	skb->ip_summed = CHECKSUM_PARTIAL;
688
689	skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
690	skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
691
692	if (skb->encapsulation)
693		skb->inner_transport_header = skb->transport_header;
694
695	return 0;
696}
697
698int udp_gro_complete(struct sk_buff *skb, int nhoff,
699		     udp_lookup_t lookup)
700{
701	__be16 newlen = htons(skb->len - nhoff);
702	struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
703	struct sock *sk;
704	int err;
705
706	uh->len = newlen;
707
708	sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
709				udp4_lib_lookup_skb, skb, uh->source, uh->dest);
710	if (sk && udp_sk(sk)->gro_complete) {
711		skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
712					: SKB_GSO_UDP_TUNNEL;
713
714		/* clear the encap mark, so that inner frag_list gro_complete
715		 * can take place
716		 */
717		NAPI_GRO_CB(skb)->encap_mark = 0;
718
719		/* Set encapsulation before calling into inner gro_complete()
720		 * functions to make them set up the inner offsets.
721		 */
722		skb->encapsulation = 1;
723		err = udp_sk(sk)->gro_complete(sk, skb,
724				nhoff + sizeof(struct udphdr));
725	} else {
726		err = udp_gro_complete_segment(skb);
727	}
728
729	if (skb->remcsum_offload)
730		skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
731
732	return err;
733}
734EXPORT_SYMBOL(udp_gro_complete);
735
736INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
737{
738	const u16 offset = NAPI_GRO_CB(skb)->network_offsets[skb->encapsulation];
739	const struct iphdr *iph = (struct iphdr *)(skb->data + offset);
740	struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
741
742	/* do fraglist only if there is no outer UDP encap (or we already processed it) */
743	if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) {
744		uh->len = htons(skb->len - nhoff);
745
746		skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
747		skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
748
749		__skb_incr_checksum_unnecessary(skb);
 
 
 
 
 
 
750
751		return 0;
752	}
753
754	if (uh->check)
755		uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
756					  iph->daddr, 0);
757
758	return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
759}
760
 
 
 
 
 
 
 
 
761int __init udpv4_offload_init(void)
762{
763	net_hotdata.udpv4_offload = (struct net_offload) {
764		.callbacks = {
765			.gso_segment = udp4_ufo_fragment,
766			.gro_receive  =	udp4_gro_receive,
767			.gro_complete =	udp4_gro_complete,
768		},
769	};
770	return inet_add_offload(&net_hotdata.udpv4_offload, IPPROTO_UDP);
771}