gro.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2#include <net/psp.h>
  3#include <net/gro.h>
  4#include <net/dst_metadata.h>
  5#include <net/busy_poll.h>
  6#include <trace/events/net.h>
  7#include <linux/skbuff_ref.h>
  8
  9#define MAX_GRO_SKBS 8
 10
 11static DEFINE_SPINLOCK(offload_lock);
 12
 13/**
 14 *	dev_add_offload - register offload handlers
 15 *	@po: protocol offload declaration
 16 *
 17 *	Add protocol offload handlers to the networking stack. The passed
 18 *	&proto_offload is linked into kernel lists and may not be freed until
 19 *	it has been removed from the kernel lists.
 20 *
 21 *	This call does not sleep therefore it can not
 22 *	guarantee all CPU's that are in middle of receiving packets
 23 *	will see the new offload handlers (until the next received packet).
 24 */
 25void dev_add_offload(struct packet_offload *po)
 26{
 27	struct packet_offload *elem;
 28
 29	spin_lock(&offload_lock);
 30	list_for_each_entry(elem, &net_hotdata.offload_base, list) {
 31		if (po->priority < elem->priority)
 32			break;
 33	}
 34	list_add_rcu(&po->list, elem->list.prev);
 35	spin_unlock(&offload_lock);
 36}
 37EXPORT_SYMBOL(dev_add_offload);
 38
 39/**
 40 *	__dev_remove_offload	 - remove offload handler
 41 *	@po: packet offload declaration
 42 *
 43 *	Remove a protocol offload handler that was previously added to the
 44 *	kernel offload handlers by dev_add_offload(). The passed &offload_type
 45 *	is removed from the kernel lists and can be freed or reused once this
 46 *	function returns.
 47 *
 48 *      The packet type might still be in use by receivers
 49 *	and must not be freed until after all the CPU's have gone
 50 *	through a quiescent state.
 51 */
 52static void __dev_remove_offload(struct packet_offload *po)
 53{
 54	struct list_head *head = &net_hotdata.offload_base;
 55	struct packet_offload *po1;
 56
 57	spin_lock(&offload_lock);
 58
 59	list_for_each_entry(po1, head, list) {
 60		if (po == po1) {
 61			list_del_rcu(&po->list);
 62			goto out;
 63		}
 64	}
 65
 66	pr_warn("dev_remove_offload: %p not found\n", po);
 67out:
 68	spin_unlock(&offload_lock);
 69}
 70
 71/**
 72 *	dev_remove_offload	 - remove packet offload handler
 73 *	@po: packet offload declaration
 74 *
 75 *	Remove a packet offload handler that was previously added to the kernel
 76 *	offload handlers by dev_add_offload(). The passed &offload_type is
 77 *	removed from the kernel lists and can be freed or reused once this
 78 *	function returns.
 79 *
 80 *	This call sleeps to guarantee that no CPU is looking at the packet
 81 *	type after return.
 82 */
 83void dev_remove_offload(struct packet_offload *po)
 84{
 85	__dev_remove_offload(po);
 86
 87	synchronize_net();
 88}
 89EXPORT_SYMBOL(dev_remove_offload);
 90
 91
 92int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb)
 93{
 94	struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb);
 95	unsigned int offset = skb_gro_offset(skb);
 96	unsigned int headlen = skb_headlen(skb);
 97	unsigned int len = skb_gro_len(skb);
 98	unsigned int delta_truesize;
 99	unsigned int new_truesize;
100	struct sk_buff *lp;
101	int segs;
102
103	/* Do not splice page pool based packets w/ non-page pool
104	 * packets. This can result in reference count issues as page
105	 * pool pages will not decrement the reference count and will
106	 * instead be immediately returned to the pool or have frag
107	 * count decremented.
108	 */
109	if (p->pp_recycle != skb->pp_recycle)
110		return -ETOOMANYREFS;
111
112	if (unlikely(p->len + len >= netif_get_gro_max_size(p->dev, p) ||
113		     NAPI_GRO_CB(skb)->flush))
114		return -E2BIG;
115
116	if (unlikely(p->len + len >= GRO_LEGACY_MAX_SIZE)) {
117		if (NAPI_GRO_CB(skb)->proto != IPPROTO_TCP ||
118		    (p->protocol == htons(ETH_P_IPV6) &&
119		     skb_headroom(p) < sizeof(struct hop_jumbo_hdr)) ||
120		    p->encapsulation)
121			return -E2BIG;
122	}
123
124	segs = NAPI_GRO_CB(skb)->count;
125	lp = NAPI_GRO_CB(p)->last;
126	pinfo = skb_shinfo(lp);
127
128	if (headlen <= offset) {
129		skb_frag_t *frag;
130		skb_frag_t *frag2;
131		int i = skbinfo->nr_frags;
132		int nr_frags = pinfo->nr_frags + i;
133
134		if (nr_frags > MAX_SKB_FRAGS)
135			goto merge;
136
137		offset -= headlen;
138		pinfo->nr_frags = nr_frags;
139		skbinfo->nr_frags = 0;
140
141		frag = pinfo->frags + nr_frags;
142		frag2 = skbinfo->frags + i;
143		do {
144			*--frag = *--frag2;
145		} while (--i);
146
147		skb_frag_off_add(frag, offset);
148		skb_frag_size_sub(frag, offset);
149
150		/* all fragments truesize : remove (head size + sk_buff) */
151		new_truesize = SKB_TRUESIZE(skb_end_offset(skb));
152		delta_truesize = skb->truesize - new_truesize;
153
154		skb->truesize = new_truesize;
155		skb->len -= skb->data_len;
156		skb->data_len = 0;
157
158		NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE;
159		goto done;
160	} else if (skb->head_frag) {
161		int nr_frags = pinfo->nr_frags;
162		skb_frag_t *frag = pinfo->frags + nr_frags;
163		struct page *page = virt_to_head_page(skb->head);
164		unsigned int first_size = headlen - offset;
165		unsigned int first_offset;
166
167		if (nr_frags + 1 + skbinfo->nr_frags > MAX_SKB_FRAGS)
168			goto merge;
169
170		first_offset = skb->data -
171			       (unsigned char *)page_address(page) +
172			       offset;
173
174		pinfo->nr_frags = nr_frags + 1 + skbinfo->nr_frags;
175
176		skb_frag_fill_page_desc(frag, page, first_offset, first_size);
177
178		memcpy(frag + 1, skbinfo->frags, sizeof(*frag) * skbinfo->nr_frags);
179		/* We dont need to clear skbinfo->nr_frags here */
180
181		new_truesize = SKB_DATA_ALIGN(sizeof(struct sk_buff));
182		delta_truesize = skb->truesize - new_truesize;
183		skb->truesize = new_truesize;
184		NAPI_GRO_CB(skb)->free = NAPI_GRO_FREE_STOLEN_HEAD;
185		goto done;
186	}
187
188merge:
189	/* sk ownership - if any - completely transferred to the aggregated packet */
190	skb->destructor = NULL;
191	skb->sk = NULL;
192	delta_truesize = skb->truesize;
193	if (offset > headlen) {
194		unsigned int eat = offset - headlen;
195
196		skb_frag_off_add(&skbinfo->frags[0], eat);
197		skb_frag_size_sub(&skbinfo->frags[0], eat);
198		skb->data_len -= eat;
199		skb->len -= eat;
200		offset = headlen;
201	}
202
203	__skb_pull(skb, offset);
204
205	if (NAPI_GRO_CB(p)->last == p)
206		skb_shinfo(p)->frag_list = skb;
207	else
208		NAPI_GRO_CB(p)->last->next = skb;
209	NAPI_GRO_CB(p)->last = skb;
210	__skb_header_release(skb);
211	lp = p;
212
213done:
214	NAPI_GRO_CB(p)->count += segs;
215	p->data_len += len;
216	p->truesize += delta_truesize;
217	p->len += len;
218	if (lp != p) {
219		lp->data_len += len;
220		lp->truesize += delta_truesize;
221		lp->len += len;
222	}
223	NAPI_GRO_CB(skb)->same_flow = 1;
224	return 0;
225}
226
227int skb_gro_receive_list(struct sk_buff *p, struct sk_buff *skb)
228{
229	if (unlikely(p->len + skb->len >= 65536))
230		return -E2BIG;
231
232	if (NAPI_GRO_CB(p)->last == p)
233		skb_shinfo(p)->frag_list = skb;
234	else
235		NAPI_GRO_CB(p)->last->next = skb;
236
237	skb_pull(skb, skb_gro_offset(skb));
238
239	NAPI_GRO_CB(p)->last = skb;
240	NAPI_GRO_CB(p)->count++;
241	p->data_len += skb->len;
242
243	/* sk ownership - if any - completely transferred to the aggregated packet */
244	skb->destructor = NULL;
245	skb->sk = NULL;
246	p->truesize += skb->truesize;
247	p->len += skb->len;
248
249	NAPI_GRO_CB(skb)->same_flow = 1;
250
251	return 0;
252}
253
254static void gro_complete(struct gro_node *gro, struct sk_buff *skb)
255{
256	struct list_head *head = &net_hotdata.offload_base;
257	struct packet_offload *ptype;
258	__be16 type = skb->protocol;
259	int err = -ENOENT;
260
261	BUILD_BUG_ON(sizeof(struct napi_gro_cb) > sizeof(skb->cb));
262
263	if (NAPI_GRO_CB(skb)->count == 1) {
264		skb_shinfo(skb)->gso_size = 0;
265		goto out;
266	}
267
268	/* NICs can feed encapsulated packets into GRO */
269	skb->encapsulation = 0;
270	rcu_read_lock();
271	list_for_each_entry_rcu(ptype, head, list) {
272		if (ptype->type != type || !ptype->callbacks.gro_complete)
273			continue;
274
275		err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
276					 ipv6_gro_complete, inet_gro_complete,
277					 skb, 0);
278		break;
279	}
280	rcu_read_unlock();
281
282	if (err) {
283		WARN_ON(&ptype->list == head);
284		kfree_skb(skb);
285		return;
286	}
287
288out:
289	gro_normal_one(gro, skb, NAPI_GRO_CB(skb)->count);
290}
291
292static void __gro_flush_chain(struct gro_node *gro, u32 index, bool flush_old)
293{
294	struct list_head *head = &gro->hash[index].list;
295	struct sk_buff *skb, *p;
296
297	list_for_each_entry_safe_reverse(skb, p, head, list) {
298		if (flush_old && NAPI_GRO_CB(skb)->age == jiffies)
299			return;
300		skb_list_del_init(skb);
301		gro_complete(gro, skb);
302		gro->hash[index].count--;
303	}
304
305	if (!gro->hash[index].count)
306		__clear_bit(index, &gro->bitmask);
307}
308
309/*
310 * gro->hash[].list contains packets ordered by age.
311 * youngest packets at the head of it.
312 * Complete skbs in reverse order to reduce latencies.
313 */
314void __gro_flush(struct gro_node *gro, bool flush_old)
315{
316	unsigned long bitmask = gro->bitmask;
317	unsigned int i, base = ~0U;
318
319	while ((i = ffs(bitmask)) != 0) {
320		bitmask >>= i;
321		base += i;
322		__gro_flush_chain(gro, base, flush_old);
323	}
324}
325EXPORT_SYMBOL(__gro_flush);
326
327static unsigned long gro_list_prepare_tc_ext(const struct sk_buff *skb,
328					     const struct sk_buff *p,
329					     unsigned long diffs)
330{
331#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
332	struct tc_skb_ext *skb_ext;
333	struct tc_skb_ext *p_ext;
334
335	skb_ext = skb_ext_find(skb, TC_SKB_EXT);
336	p_ext = skb_ext_find(p, TC_SKB_EXT);
337
338	diffs |= (!!p_ext) ^ (!!skb_ext);
339	if (!diffs && unlikely(skb_ext))
340		diffs |= p_ext->chain ^ skb_ext->chain;
341#endif
342	return diffs;
343}
344
345static void gro_list_prepare(const struct list_head *head,
346			     const struct sk_buff *skb)
347{
348	unsigned int maclen = skb->dev->hard_header_len;
349	u32 hash = skb_get_hash_raw(skb);
350	struct sk_buff *p;
351
352	list_for_each_entry(p, head, list) {
353		unsigned long diffs;
354
355		if (hash != skb_get_hash_raw(p)) {
356			NAPI_GRO_CB(p)->same_flow = 0;
357			continue;
358		}
359
360		diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev;
361		diffs |= p->vlan_all ^ skb->vlan_all;
362		diffs |= skb_metadata_differs(p, skb);
363		if (maclen == ETH_HLEN)
364			diffs |= compare_ether_header(skb_mac_header(p),
365						      skb_mac_header(skb));
366		else if (!diffs)
367			diffs = memcmp(skb_mac_header(p),
368				       skb_mac_header(skb),
369				       maclen);
370
371		/* in most common scenarios 'slow_gro' is 0
372		 * otherwise we are already on some slower paths
373		 * either skip all the infrequent tests altogether or
374		 * avoid trying too hard to skip each of them individually
375		 */
376		if (!diffs && unlikely(skb->slow_gro | p->slow_gro)) {
377			diffs |= p->sk != skb->sk;
378			diffs |= skb_metadata_dst_cmp(p, skb);
379			diffs |= skb_get_nfct(p) ^ skb_get_nfct(skb);
380
381			diffs |= gro_list_prepare_tc_ext(skb, p, diffs);
382			diffs |= __psp_skb_coalesce_diff(skb, p, diffs);
383		}
384
385		NAPI_GRO_CB(p)->same_flow = !diffs;
386	}
387}
388
389static inline void skb_gro_reset_offset(struct sk_buff *skb, u32 nhoff)
390{
391	const struct skb_shared_info *pinfo;
392	const skb_frag_t *frag0;
393	unsigned int headlen;
394
395	NAPI_GRO_CB(skb)->network_offset = 0;
396	NAPI_GRO_CB(skb)->data_offset = 0;
397	headlen = skb_headlen(skb);
398	NAPI_GRO_CB(skb)->frag0 = skb->data;
399	NAPI_GRO_CB(skb)->frag0_len = headlen;
400	if (headlen)
401		return;
402
403	pinfo = skb_shinfo(skb);
404	frag0 = &pinfo->frags[0];
405
406	if (pinfo->nr_frags && skb_frag_page(frag0) &&
407	    !PageHighMem(skb_frag_page(frag0)) &&
408	    (!NET_IP_ALIGN || !((skb_frag_off(frag0) + nhoff) & 3))) {
409		NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0);
410		NAPI_GRO_CB(skb)->frag0_len = min_t(unsigned int,
411						    skb_frag_size(frag0),
412						    skb->end - skb->tail);
413	}
414}
415
416static void gro_pull_from_frag0(struct sk_buff *skb, int grow)
417{
418	struct skb_shared_info *pinfo = skb_shinfo(skb);
419
420	DEBUG_NET_WARN_ON_ONCE(skb->end - skb->tail < grow);
421
422	memcpy(skb_tail_pointer(skb), NAPI_GRO_CB(skb)->frag0, grow);
423
424	skb->data_len -= grow;
425	skb->tail += grow;
426
427	skb_frag_off_add(&pinfo->frags[0], grow);
428	skb_frag_size_sub(&pinfo->frags[0], grow);
429
430	if (unlikely(!skb_frag_size(&pinfo->frags[0]))) {
431		skb_frag_unref(skb, 0);
432		memmove(pinfo->frags, pinfo->frags + 1,
433			--pinfo->nr_frags * sizeof(pinfo->frags[0]));
434	}
435}
436
437static void gro_try_pull_from_frag0(struct sk_buff *skb)
438{
439	int grow = skb_gro_offset(skb) - skb_headlen(skb);
440
441	if (grow > 0)
442		gro_pull_from_frag0(skb, grow);
443}
444
445static void gro_flush_oldest(struct gro_node *gro, struct list_head *head)
446{
447	struct sk_buff *oldest;
448
449	oldest = list_last_entry(head, struct sk_buff, list);
450
451	/* We are called with head length >= MAX_GRO_SKBS, so this is
452	 * impossible.
453	 */
454	if (WARN_ON_ONCE(!oldest))
455		return;
456
457	/* Do not adjust napi->gro_hash[].count, caller is adding a new
458	 * SKB to the chain.
459	 */
460	skb_list_del_init(oldest);
461	gro_complete(gro, oldest);
462}
463
464static enum gro_result dev_gro_receive(struct gro_node *gro,
465				       struct sk_buff *skb)
466{
467	u32 bucket = skb_get_hash_raw(skb) & (GRO_HASH_BUCKETS - 1);
468	struct list_head *head = &net_hotdata.offload_base;
469	struct gro_list *gro_list = &gro->hash[bucket];
470	struct packet_offload *ptype;
471	__be16 type = skb->protocol;
472	struct sk_buff *pp = NULL;
473	enum gro_result ret;
474	int same_flow;
475
476	if (netif_elide_gro(skb->dev))
477		goto normal;
478
479	gro_list_prepare(&gro_list->list, skb);
480
481	rcu_read_lock();
482	list_for_each_entry_rcu(ptype, head, list) {
483		if (ptype->type == type && ptype->callbacks.gro_receive)
484			goto found_ptype;
485	}
486	rcu_read_unlock();
487	goto normal;
488
489found_ptype:
490	skb_set_network_header(skb, skb_gro_offset(skb));
491	skb_reset_mac_len(skb);
492	BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32));
493	BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed),
494					sizeof(u32))); /* Avoid slow unaligned acc */
495	*(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0;
496	NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb);
497	NAPI_GRO_CB(skb)->count = 1;
498	if (unlikely(skb_is_gso(skb))) {
499		NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs;
500		/* Only support TCP and non DODGY users. */
501		if (!skb_is_gso_tcp(skb) ||
502		    (skb_shinfo(skb)->gso_type & SKB_GSO_DODGY))
503			NAPI_GRO_CB(skb)->flush = 1;
504	}
505
506	/* Setup for GRO checksum validation */
507	switch (skb->ip_summed) {
508	case CHECKSUM_COMPLETE:
509		NAPI_GRO_CB(skb)->csum = skb->csum;
510		NAPI_GRO_CB(skb)->csum_valid = 1;
511		break;
512	case CHECKSUM_UNNECESSARY:
513		NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1;
514		break;
515	}
516
517	pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive,
518				ipv6_gro_receive, inet_gro_receive,
519				&gro_list->list, skb);
520
521	rcu_read_unlock();
522
523	if (PTR_ERR(pp) == -EINPROGRESS) {
524		ret = GRO_CONSUMED;
525		goto ok;
526	}
527
528	same_flow = NAPI_GRO_CB(skb)->same_flow;
529	ret = NAPI_GRO_CB(skb)->free ? GRO_MERGED_FREE : GRO_MERGED;
530
531	if (pp) {
532		skb_list_del_init(pp);
533		gro_complete(gro, pp);
534		gro_list->count--;
535	}
536
537	if (same_flow)
538		goto ok;
539
540	if (NAPI_GRO_CB(skb)->flush)
541		goto normal;
542
543	if (unlikely(gro_list->count >= MAX_GRO_SKBS))
544		gro_flush_oldest(gro, &gro_list->list);
545	else
546		gro_list->count++;
547
548	/* Must be called before setting NAPI_GRO_CB(skb)->{age|last} */
549	gro_try_pull_from_frag0(skb);
550	NAPI_GRO_CB(skb)->age = jiffies;
551	NAPI_GRO_CB(skb)->last = skb;
552	if (!skb_is_gso(skb))
553		skb_shinfo(skb)->gso_size = skb_gro_len(skb);
554	list_add(&skb->list, &gro_list->list);
555	ret = GRO_HELD;
556ok:
557	if (gro_list->count) {
558		if (!test_bit(bucket, &gro->bitmask))
559			__set_bit(bucket, &gro->bitmask);
560	} else if (test_bit(bucket, &gro->bitmask)) {
561		__clear_bit(bucket, &gro->bitmask);
562	}
563
564	return ret;
565
566normal:
567	ret = GRO_NORMAL;
568	gro_try_pull_from_frag0(skb);
569	goto ok;
570}
571
572struct packet_offload *gro_find_receive_by_type(__be16 type)
573{
574	struct list_head *offload_head = &net_hotdata.offload_base;
575	struct packet_offload *ptype;
576
577	list_for_each_entry_rcu(ptype, offload_head, list) {
578		if (ptype->type != type || !ptype->callbacks.gro_receive)
579			continue;
580		return ptype;
581	}
582	return NULL;
583}
584EXPORT_SYMBOL(gro_find_receive_by_type);
585
586struct packet_offload *gro_find_complete_by_type(__be16 type)
587{
588	struct list_head *offload_head = &net_hotdata.offload_base;
589	struct packet_offload *ptype;
590
591	list_for_each_entry_rcu(ptype, offload_head, list) {
592		if (ptype->type != type || !ptype->callbacks.gro_complete)
593			continue;
594		return ptype;
595	}
596	return NULL;
597}
598EXPORT_SYMBOL(gro_find_complete_by_type);
599
600static gro_result_t gro_skb_finish(struct gro_node *gro, struct sk_buff *skb,
601				   gro_result_t ret)
602{
603	switch (ret) {
604	case GRO_NORMAL:
605		gro_normal_one(gro, skb, 1);
606		break;
607
608	case GRO_MERGED_FREE:
609		if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD)
610			napi_skb_free_stolen_head(skb);
611		else if (skb->fclone != SKB_FCLONE_UNAVAILABLE)
612			__kfree_skb(skb);
613		else
614			__napi_kfree_skb(skb, SKB_CONSUMED);
615		break;
616
617	case GRO_HELD:
618	case GRO_MERGED:
619	case GRO_CONSUMED:
620		break;
621	}
622
623	return ret;
624}
625
626gro_result_t gro_receive_skb(struct gro_node *gro, struct sk_buff *skb)
627{
628	gro_result_t ret;
629
630	__skb_mark_napi_id(skb, gro);
631	trace_napi_gro_receive_entry(skb);
632
633	skb_gro_reset_offset(skb, 0);
634
635	ret = gro_skb_finish(gro, skb, dev_gro_receive(gro, skb));
636	trace_napi_gro_receive_exit(ret);
637
638	return ret;
639}
640EXPORT_SYMBOL(gro_receive_skb);
641
642static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
643{
644	struct skb_shared_info *shinfo;
645
646	if (unlikely(skb->pfmemalloc)) {
647		consume_skb(skb);
648		return;
649	}
650	__skb_pull(skb, skb_headlen(skb));
651	/* restore the reserve we had after netdev_alloc_skb_ip_align() */
652	skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN - skb_headroom(skb));
653	__vlan_hwaccel_clear_tag(skb);
654	skb->dev = napi->dev;
655	skb->skb_iif = 0;
656
657	/* eth_type_trans() assumes pkt_type is PACKET_HOST */
658	skb->pkt_type = PACKET_HOST;
659
660	skb->encapsulation = 0;
661	skb->ip_summed = CHECKSUM_NONE;
662
663	shinfo = skb_shinfo(skb);
664	shinfo->gso_type = 0;
665	shinfo->gso_size = 0;
666	shinfo->hwtstamps.hwtstamp = 0;
667
668	if (unlikely(skb->slow_gro)) {
669		skb_orphan(skb);
670		skb_ext_reset(skb);
671		nf_reset_ct(skb);
672		skb->slow_gro = 0;
673	}
674
675	napi->skb = skb;
676}
677
678struct sk_buff *napi_get_frags(struct napi_struct *napi)
679{
680	struct sk_buff *skb = napi->skb;
681
682	if (!skb) {
683		skb = napi_alloc_skb(napi, GRO_MAX_HEAD);
684		if (skb) {
685			napi->skb = skb;
686			skb_mark_napi_id(skb, napi);
687		}
688	}
689	return skb;
690}
691EXPORT_SYMBOL(napi_get_frags);
692
693static gro_result_t napi_frags_finish(struct napi_struct *napi,
694				      struct sk_buff *skb,
695				      gro_result_t ret)
696{
697	switch (ret) {
698	case GRO_NORMAL:
699	case GRO_HELD:
700		__skb_push(skb, ETH_HLEN);
701		skb->protocol = eth_type_trans(skb, skb->dev);
702		if (ret == GRO_NORMAL)
703			gro_normal_one(&napi->gro, skb, 1);
704		break;
705
706	case GRO_MERGED_FREE:
707		if (NAPI_GRO_CB(skb)->free == NAPI_GRO_FREE_STOLEN_HEAD)
708			napi_skb_free_stolen_head(skb);
709		else
710			napi_reuse_skb(napi, skb);
711		break;
712
713	case GRO_MERGED:
714	case GRO_CONSUMED:
715		break;
716	}
717
718	return ret;
719}
720
721/* Upper GRO stack assumes network header starts at gro_offset=0
722 * Drivers could call both napi_gro_frags() and napi_gro_receive()
723 * We copy ethernet header into skb->data to have a common layout.
724 */
725static struct sk_buff *napi_frags_skb(struct napi_struct *napi)
726{
727	struct sk_buff *skb = napi->skb;
728	const struct ethhdr *eth;
729	unsigned int hlen = sizeof(*eth);
730
731	napi->skb = NULL;
732
733	skb_reset_mac_header(skb);
734	skb_gro_reset_offset(skb, hlen);
735
736	if (unlikely(!skb_gro_may_pull(skb, hlen))) {
737		eth = skb_gro_header_slow(skb, hlen, 0);
738		if (unlikely(!eth)) {
739			net_warn_ratelimited("%s: dropping impossible skb from %s\n",
740					     __func__, napi->dev->name);
741			napi_reuse_skb(napi, skb);
742			return NULL;
743		}
744	} else {
745		eth = (const struct ethhdr *)skb->data;
746
747		if (NAPI_GRO_CB(skb)->frag0 != skb->data)
748			gro_pull_from_frag0(skb, hlen);
749
750		NAPI_GRO_CB(skb)->frag0 += hlen;
751		NAPI_GRO_CB(skb)->frag0_len -= hlen;
752	}
753	__skb_pull(skb, hlen);
754
755	/*
756	 * This works because the only protocols we care about don't require
757	 * special handling.
758	 * We'll fix it up properly in napi_frags_finish()
759	 */
760	skb->protocol = eth->h_proto;
761
762	return skb;
763}
764
765gro_result_t napi_gro_frags(struct napi_struct *napi)
766{
767	gro_result_t ret;
768	struct sk_buff *skb = napi_frags_skb(napi);
769
770	trace_napi_gro_frags_entry(skb);
771
772	ret = napi_frags_finish(napi, skb, dev_gro_receive(&napi->gro, skb));
773	trace_napi_gro_frags_exit(ret);
774
775	return ret;
776}
777EXPORT_SYMBOL(napi_gro_frags);
778
779/* Compute the checksum from gro_offset and return the folded value
780 * after adding in any pseudo checksum.
781 */
782__sum16 __skb_gro_checksum_complete(struct sk_buff *skb)
783{
784	__wsum wsum;
785	__sum16 sum;
786
787	wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), 0);
788
789	/* NAPI_GRO_CB(skb)->csum holds pseudo checksum */
790	sum = csum_fold(csum_add(NAPI_GRO_CB(skb)->csum, wsum));
791	/* See comments in __skb_checksum_complete(). */
792	if (likely(!sum)) {
793		if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
794		    !skb->csum_complete_sw)
795			netdev_rx_csum_fault(skb->dev, skb);
796	}
797
798	NAPI_GRO_CB(skb)->csum = wsum;
799	NAPI_GRO_CB(skb)->csum_valid = 1;
800
801	return sum;
802}
803EXPORT_SYMBOL(__skb_gro_checksum_complete);
804
805void gro_init(struct gro_node *gro)
806{
807	for (u32 i = 0; i < GRO_HASH_BUCKETS; i++) {
808		INIT_LIST_HEAD(&gro->hash[i].list);
809		gro->hash[i].count = 0;
810	}
811
812	gro->bitmask = 0;
813	gro->cached_napi_id = 0;
814
815	INIT_LIST_HEAD(&gro->rx_list);
816	gro->rx_count = 0;
817}
818
819void gro_cleanup(struct gro_node *gro)
820{
821	struct sk_buff *skb, *n;
822
823	for (u32 i = 0; i < GRO_HASH_BUCKETS; i++) {
824		list_for_each_entry_safe(skb, n, &gro->hash[i].list, list)
825			kfree_skb(skb);
826
827		gro->hash[i].count = 0;
828	}
829
830	gro->bitmask = 0;
831	gro->cached_napi_id = 0;
832
833	list_for_each_entry_safe(skb, n, &gro->rx_list, list)
834		kfree_skb(skb);
835
836	gro->rx_count = 0;
837}