[linux-2.6-block.git] / net / ipv4 / tcp_offload.c

/*
 *	IPV4 GSO/GRO offload support
 *	Linux INET implementation
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 *
 *	TCPv4 GSO/GRO support
 */

#include <linux/indirect_call_wrapper.h>
#include <linux/skbuff.h>
#include <net/tcp.h>
#include <net/protocol.h>

static void tcp_gso_tstamp(struct sk_buff *skb, unsigned int ts_seq,
			   unsigned int seq, unsigned int mss)
{
	while (skb) {
		if (before(ts_seq, seq + mss)) {
			skb_shinfo(skb)->tx_flags |= SKBTX_SW_TSTAMP;
			skb_shinfo(skb)->tskey = ts_seq;
			return;
		}

		skb = skb->next;
		seq += mss;
	}
}

static struct sk_buff *tcp4_gso_segment(struct sk_buff *skb,
					netdev_features_t features)
{
	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4))
		return ERR_PTR(-EINVAL);

	if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
		return ERR_PTR(-EINVAL);

	if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
		const struct iphdr *iph = ip_hdr(skb);
		struct tcphdr *th = tcp_hdr(skb);

		/* Set up checksum pseudo header, usually expect stack to
		 * have done this already.
		 */

		th->check = 0;
		skb->ip_summed = CHECKSUM_PARTIAL;
		__tcp_v4_send_check(skb, iph->saddr, iph->daddr);
	}

	return tcp_gso_segment(skb, features);
}

struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
				netdev_features_t features)
{
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	unsigned int sum_truesize = 0;
	struct tcphdr *th;
	unsigned int thlen;
	unsigned int seq;
	__be32 delta;
	unsigned int oldlen;
	unsigned int mss;
	struct sk_buff *gso_skb = skb;
	__sum16 newcheck;
	bool ooo_okay, copy_destructor;

	th = tcp_hdr(skb);
	thlen = th->doff * 4;
	if (thlen < sizeof(*th))
		goto out;

	if (!pskb_may_pull(skb, thlen))
		goto out;

	oldlen = (u16)~skb->len;
	__skb_pull(skb, thlen);

	mss = skb_shinfo(skb)->gso_size;
	if (unlikely(skb->len <= mss))
		goto out;

	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
		/* Packet is from an untrusted source, reset gso_segs. */

		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);

		segs = NULL;
		goto out;
	}

	copy_destructor = gso_skb->destructor == tcp_wfree;
	ooo_okay = gso_skb->ooo_okay;
	/* All segments but the first should have ooo_okay cleared */
	skb->ooo_okay = 0;

	segs = skb_segment(skb, features);
	if (IS_ERR(segs))
		goto out;

	/* Only first segment might have ooo_okay set */
	segs->ooo_okay = ooo_okay;

	/* GSO partial and frag_list segmentation only requires splitting
	 * the frame into an MSS multiple and possibly a remainder, both
	 * cases return a GSO skb. So update the mss now.
	 */
	if (skb_is_gso(segs))
		mss *= skb_shinfo(segs)->gso_segs;

	delta = htonl(oldlen + (thlen + mss));

	skb = segs;
	th = tcp_hdr(skb);
	seq = ntohl(th->seq);

	if (unlikely(skb_shinfo(gso_skb)->tx_flags & SKBTX_SW_TSTAMP))
		tcp_gso_tstamp(segs, skb_shinfo(gso_skb)->tskey, seq, mss);

	newcheck = ~csum_fold((__force __wsum)((__force u32)th->check +
					       (__force u32)delta));

	while (skb->next) {
		th->fin = th->psh = 0;
		th->check = newcheck;

		if (skb->ip_summed == CHECKSUM_PARTIAL)
			gso_reset_checksum(skb, ~th->check);
		else
			th->check = gso_make_checksum(skb, ~th->check);

		seq += mss;
		if (copy_destructor) {
			skb->destructor = gso_skb->destructor;
			skb->sk = gso_skb->sk;
			sum_truesize += skb->truesize;
		}
		skb = skb->next;
		th = tcp_hdr(skb);

		th->seq = htonl(seq);
		th->cwr = 0;
	}

	/* Following permits TCP Small Queues to work well with GSO :
	 * The callback to TCP stack will be called at the time last frag
	 * is freed at TX completion, and not right now when gso_skb
	 * is freed by GSO engine
	 */
	if (copy_destructor) {
		int delta;

		swap(gso_skb->sk, skb->sk);
		swap(gso_skb->destructor, skb->destructor);
		sum_truesize += skb->truesize;
		delta = sum_truesize - gso_skb->truesize;
		/* In some pathological cases, delta can be negative.
		 * We need to either use refcount_add() or refcount_sub_and_test()
		 */
		if (likely(delta >= 0))
			refcount_add(delta, &skb->sk->sk_wmem_alloc);
		else
			WARN_ON_ONCE(refcount_sub_and_test(-delta, &skb->sk->sk_wmem_alloc));
	}

	delta = htonl(oldlen + (skb_tail_pointer(skb) -
				skb_transport_header(skb)) +
		      skb->data_len);
	th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
				(__force u32)delta));
	if (skb->ip_summed == CHECKSUM_PARTIAL)
		gso_reset_checksum(skb, ~th->check);
	else
		th->check = gso_make_checksum(skb, ~th->check);
out:
	return segs;
}

struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb)
{
	struct sk_buff *pp = NULL;
	struct sk_buff *p;
	struct tcphdr *th;
	struct tcphdr *th2;
	unsigned int len;
	unsigned int thlen;
	__be32 flags;
	unsigned int mss = 1;
	unsigned int hlen;
	unsigned int off;
	int flush = 1;
	int i;

	off = skb_gro_offset(skb);
	hlen = off + sizeof(*th);
	th = skb_gro_header_fast(skb, off);
	if (skb_gro_header_hard(skb, hlen)) {
		th = skb_gro_header_slow(skb, hlen, off);
		if (unlikely(!th))
			goto out;
	}

	thlen = th->doff * 4;
	if (thlen < sizeof(*th))
		goto out;

	hlen = off + thlen;
	if (skb_gro_header_hard(skb, hlen)) {
		th = skb_gro_header_slow(skb, hlen, off);
		if (unlikely(!th))
			goto out;
	}

	skb_gro_pull(skb, thlen);

	len = skb_gro_len(skb);
	flags = tcp_flag_word(th);

	list_for_each_entry(p, head, list) {
		if (!NAPI_GRO_CB(p)->same_flow)
			continue;

		th2 = tcp_hdr(p);

		if (*(u32 *)&th->source ^ *(u32 *)&th2->source) {
			NAPI_GRO_CB(p)->same_flow = 0;
			continue;
		}

		goto found;
	}
	p = NULL;
	goto out_check_final;

found:
	/* Include the IP ID check below from the inner most IP hdr */
	flush = NAPI_GRO_CB(p)->flush;
	flush |= (__force int)(flags & TCP_FLAG_CWR);
	flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
		  ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
	flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
	for (i = sizeof(*th); i < thlen; i += 4)
		flush |= *(u32 *)((u8 *)th + i) ^
			 *(u32 *)((u8 *)th2 + i);

	/* When we receive our second frame we can made a decision on if we
	 * continue this flow as an atomic flow with a fixed ID or if we use
	 * an incrementing ID.
	 */
	if (NAPI_GRO_CB(p)->flush_id != 1 ||
	    NAPI_GRO_CB(p)->count != 1 ||
	    !NAPI_GRO_CB(p)->is_atomic)
		flush |= NAPI_GRO_CB(p)->flush_id;
	else
		NAPI_GRO_CB(p)->is_atomic = false;

	mss = skb_shinfo(p)->gso_size;

	flush |= (len - 1) >= mss;
	flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
#ifdef CONFIG_TLS_DEVICE
	flush |= p->decrypted ^ skb->decrypted;
#endif

	if (flush || skb_gro_receive(p, skb)) {
		mss = 1;
		goto out_check_final;
	}

	tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH);

out_check_final:
	flush = len < mss;
	flush |= (__force int)(flags & (TCP_FLAG_URG | TCP_FLAG_PSH |
					TCP_FLAG_RST | TCP_FLAG_SYN |
					TCP_FLAG_FIN));

	if (p && (!NAPI_GRO_CB(skb)->same_flow || flush))
		pp = p;

out:
	NAPI_GRO_CB(skb)->flush |= (flush != 0);

	return pp;
}

int tcp_gro_complete(struct sk_buff *skb)
{
	struct tcphdr *th = tcp_hdr(skb);

	skb->csum_start = (unsigned char *)th - skb->head;
	skb->csum_offset = offsetof(struct tcphdr, check);
	skb->ip_summed = CHECKSUM_PARTIAL;

	skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;

	if (th->cwr)
		skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;

	return 0;
}
EXPORT_SYMBOL(tcp_gro_complete);

INDIRECT_CALLABLE_SCOPE
struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb)
{
	/* Don't bother verifying checksum if we're going to flush anyway. */
	if (!NAPI_GRO_CB(skb)->flush &&
	    skb_gro_checksum_validate(skb, IPPROTO_TCP,
				      inet_gro_compute_pseudo)) {
		NAPI_GRO_CB(skb)->flush = 1;
		return NULL;
	}

	return tcp_gro_receive(head, skb);
}

INDIRECT_CALLABLE_SCOPE int tcp4_gro_complete(struct sk_buff *skb, int thoff)
{
	const struct iphdr *iph = ip_hdr(skb);
	struct tcphdr *th = tcp_hdr(skb);

	th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr,
				  iph->daddr, 0);
	skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;

	if (NAPI_GRO_CB(skb)->is_atomic)
		skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_FIXEDID;

	return tcp_gro_complete(skb);
}

static const struct net_offload tcpv4_offload = {
	.callbacks = {
		.gso_segment	=	tcp4_gso_segment,
		.gro_receive	=	tcp4_gro_receive,
		.gro_complete	=	tcp4_gro_complete,
	},
};

int __init tcpv4_offload_init(void)
{
	return inet_add_offload(&tcpv4_offload, IPPROTO_TCP);
}
Commit	Line	Data
28850dc7 DB	1	/*
	2	* IPV4 GSO/GRO offload support
	3	* Linux INET implementation
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License
	7	* as published by the Free Software Foundation; either version
	8	* 2 of the License, or (at your option) any later version.
	9	*
	10	* TCPv4 GSO/GRO support
	11	*/
	12
028e0a47	13	#include <linux/indirect_call_wrapper.h>
28850dc7 DB	14	#include <linux/skbuff.h>
	15	#include <net/tcp.h>
	16	#include <net/protocol.h>
	17
f066e2b0 WB	18	static void tcp_gso_tstamp(struct sk_buff *skb, unsigned int ts_seq,
f066e2b0 WB	19	unsigned int seq, unsigned int mss)
4ed2d765 WB	20	{
4ed2d765 WB	21	while (skb) {
f066e2b0 WB	22	if (before(ts_seq, seq + mss)) {
f066e2b0 WB	23	skb_shinfo(skb)->tx_flags \|= SKBTX_SW_TSTAMP;
4ed2d765 WB	24	skb_shinfo(skb)->tskey = ts_seq;
	25	return;
	26	}
	27
	28	skb = skb->next;
	29	seq += mss;
	30	}
	31	}
	32
74abc20c ED	33	static struct sk_buff tcp4_gso_segment(struct sk_buff skb,
74abc20c ED	34	netdev_features_t features)
d020f8f7	35	{
121d57af WB	36	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4))
	37	return ERR_PTR(-EINVAL);
	38
d020f8f7 TH	39	if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
	40	return ERR_PTR(-EINVAL);
	41
	42	if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
	43	const struct iphdr *iph = ip_hdr(skb);
	44	struct tcphdr *th = tcp_hdr(skb);
	45
	46	/* Set up checksum pseudo header, usually expect stack to
	47	* have done this already.
	48	*/
	49
	50	th->check = 0;
	51	skb->ip_summed = CHECKSUM_PARTIAL;
	52	__tcp_v4_send_check(skb, iph->saddr, iph->daddr);
	53	}
	54
	55	return tcp_gso_segment(skb, features);
	56	}
	57
28be6e07	58	struct sk_buff tcp_gso_segment(struct sk_buff skb,
28850dc7 DB	59	netdev_features_t features)
	60	{
	61	struct sk_buff *segs = ERR_PTR(-EINVAL);
0d08c42c	62	unsigned int sum_truesize = 0;
28850dc7 DB	63	struct tcphdr *th;
	64	unsigned int thlen;
	65	unsigned int seq;
	66	__be32 delta;
	67	unsigned int oldlen;
	68	unsigned int mss;
	69	struct sk_buff *gso_skb = skb;
	70	__sum16 newcheck;
	71	bool ooo_okay, copy_destructor;
	72
28850dc7 DB	73	th = tcp_hdr(skb);
	74	thlen = th->doff * 4;
	75	if (thlen < sizeof(*th))
	76	goto out;
	77
	78	if (!pskb_may_pull(skb, thlen))
	79	goto out;
	80
	81	oldlen = (u16)~skb->len;
	82	__skb_pull(skb, thlen);
	83
a7eea416	84	mss = skb_shinfo(skb)->gso_size;
28850dc7 DB	85	if (unlikely(skb->len <= mss))
	86	goto out;
	87
	88	if (skb_gso_ok(skb, features \| NETIF_F_GSO_ROBUST)) {
	89	/* Packet is from an untrusted source, reset gso_segs. */
28850dc7 DB	90
	91	skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
	92
	93	segs = NULL;
	94	goto out;
	95	}
	96
	97	copy_destructor = gso_skb->destructor == tcp_wfree;
	98	ooo_okay = gso_skb->ooo_okay;
	99	/* All segments but the first should have ooo_okay cleared */
	100	skb->ooo_okay = 0;
	101
	102	segs = skb_segment(skb, features);
	103	if (IS_ERR(segs))
	104	goto out;
	105
	106	/* Only first segment might have ooo_okay set */
	107	segs->ooo_okay = ooo_okay;
	108
07b26c94 SK	109	/* GSO partial and frag_list segmentation only requires splitting
	110	* the frame into an MSS multiple and possibly a remainder, both
	111	* cases return a GSO skb. So update the mss now.
	112	*/
	113	if (skb_is_gso(segs))
	114	mss *= skb_shinfo(segs)->gso_segs;
	115
28850dc7 DB	116	delta = htonl(oldlen + (thlen + mss));
	117
	118	skb = segs;
	119	th = tcp_hdr(skb);
	120	seq = ntohl(th->seq);
	121
4ed2d765 WB	122	if (unlikely(skb_shinfo(gso_skb)->tx_flags & SKBTX_SW_TSTAMP))
	123	tcp_gso_tstamp(segs, skb_shinfo(gso_skb)->tskey, seq, mss);
	124
28850dc7 DB	125	newcheck = ~csum_fold((__force __wsum)((__force u32)th->check +
	126	(__force u32)delta));
	127
802ab55a	128	while (skb->next) {
28850dc7 DB	129	th->fin = th->psh = 0;
	130	th->check = newcheck;
	131
08b64fcc AD	132	if (skb->ip_summed == CHECKSUM_PARTIAL)
	133	gso_reset_checksum(skb, ~th->check);
	134	else
e9c3a24b	135	th->check = gso_make_checksum(skb, ~th->check);
28850dc7 DB	136
	137	seq += mss;
	138	if (copy_destructor) {
	139	skb->destructor = gso_skb->destructor;
	140	skb->sk = gso_skb->sk;
0d08c42c	141	sum_truesize += skb->truesize;
28850dc7 DB	142	}
	143	skb = skb->next;
	144	th = tcp_hdr(skb);
	145
	146	th->seq = htonl(seq);
	147	th->cwr = 0;
802ab55a	148	}
28850dc7 DB	149
	150	/* Following permits TCP Small Queues to work well with GSO :
	151	* The callback to TCP stack will be called at the time last frag
	152	* is freed at TX completion, and not right now when gso_skb
	153	* is freed by GSO engine
	154	*/
	155	if (copy_destructor) {
7ec318fe ED	156	int delta;
7ec318fe ED	157
28850dc7 DB	158	swap(gso_skb->sk, skb->sk);
28850dc7 DB	159	swap(gso_skb->destructor, skb->destructor);
0d08c42c	160	sum_truesize += skb->truesize;
7ec318fe ED	161	delta = sum_truesize - gso_skb->truesize;
	162	/* In some pathological cases, delta can be negative.
	163	* We need to either use refcount_add() or refcount_sub_and_test()
	164	*/
	165	if (likely(delta >= 0))
	166	refcount_add(delta, &skb->sk->sk_wmem_alloc);
	167	else
	168	WARN_ON_ONCE(refcount_sub_and_test(-delta, &skb->sk->sk_wmem_alloc));
28850dc7 DB	169	}
	170
	171	delta = htonl(oldlen + (skb_tail_pointer(skb) -
	172	skb_transport_header(skb)) +
	173	skb->data_len);
	174	th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
	175	(__force u32)delta));
08b64fcc AD	176	if (skb->ip_summed == CHECKSUM_PARTIAL)
	177	gso_reset_checksum(skb, ~th->check);
	178	else
e9c3a24b	179	th->check = gso_make_checksum(skb, ~th->check);
28850dc7 DB	180	out:
	181	return segs;
	182	}
28850dc7	183
d4546c25	184	struct sk_buff tcp_gro_receive(struct list_head head, struct sk_buff *skb)
28850dc7	185	{
d4546c25	186	struct sk_buff *pp = NULL;
28850dc7 DB	187	struct sk_buff *p;
	188	struct tcphdr *th;
	189	struct tcphdr *th2;
	190	unsigned int len;
	191	unsigned int thlen;
	192	__be32 flags;
	193	unsigned int mss = 1;
	194	unsigned int hlen;
	195	unsigned int off;
	196	int flush = 1;
	197	int i;
	198
	199	off = skb_gro_offset(skb);
	200	hlen = off + sizeof(*th);
	201	th = skb_gro_header_fast(skb, off);
	202	if (skb_gro_header_hard(skb, hlen)) {
	203	th = skb_gro_header_slow(skb, hlen, off);
	204	if (unlikely(!th))
	205	goto out;
	206	}
	207
	208	thlen = th->doff * 4;
	209	if (thlen < sizeof(*th))
	210	goto out;
	211
	212	hlen = off + thlen;
	213	if (skb_gro_header_hard(skb, hlen)) {
	214	th = skb_gro_header_slow(skb, hlen, off);
	215	if (unlikely(!th))
	216	goto out;
	217	}
	218
	219	skb_gro_pull(skb, thlen);
	220
	221	len = skb_gro_len(skb);
	222	flags = tcp_flag_word(th);
	223
d4546c25	224	list_for_each_entry(p, head, list) {
28850dc7 DB	225	if (!NAPI_GRO_CB(p)->same_flow)
	226	continue;
	227
	228	th2 = tcp_hdr(p);
	229
	230	if ((u32 )&th->source ^ (u32 )&th2->source) {
	231	NAPI_GRO_CB(p)->same_flow = 0;
	232	continue;
	233	}
	234
	235	goto found;
	236	}
d4546c25	237	p = NULL;
28850dc7 DB	238	goto out_check_final;
	239
	240	found:
bf5a755f	241	/* Include the IP ID check below from the inner most IP hdr */
1530545e	242	flush = NAPI_GRO_CB(p)->flush;
28850dc7 DB	243	flush \|= (__force int)(flags & TCP_FLAG_CWR);
	244	flush \|= (__force int)((flags ^ tcp_flag_word(th2)) &
	245	~(TCP_FLAG_CWR \| TCP_FLAG_FIN \| TCP_FLAG_PSH));
	246	flush \|= (__force int)(th->ack_seq ^ th2->ack_seq);
	247	for (i = sizeof(*th); i < thlen; i += 4)
	248	flush \|= (u32 )((u8 *)th + i) ^
	249	(u32 )((u8 *)th2 + i);
	250
1530545e AD	251	/* When we receive our second frame we can made a decision on if we
	252	* continue this flow as an atomic flow with a fixed ID or if we use
	253	* an incrementing ID.
	254	*/
	255	if (NAPI_GRO_CB(p)->flush_id != 1 \|\|
	256	NAPI_GRO_CB(p)->count != 1 \|\|
	257	!NAPI_GRO_CB(p)->is_atomic)
	258	flush \|= NAPI_GRO_CB(p)->flush_id;
	259	else
	260	NAPI_GRO_CB(p)->is_atomic = false;
	261
a7eea416	262	mss = skb_shinfo(p)->gso_size;
28850dc7 DB	263
	264	flush \|= (len - 1) >= mss;
	265	flush \|= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
41ed9c04 BP	266	#ifdef CONFIG_TLS_DEVICE
	267	flush \|= p->decrypted ^ skb->decrypted;
	268	#endif
28850dc7	269
d4546c25	270	if (flush \|\| skb_gro_receive(p, skb)) {
28850dc7 DB	271	mss = 1;
	272	goto out_check_final;
	273	}
	274
28850dc7 DB	275	tcp_flag_word(th2) \|= flags & (TCP_FLAG_FIN \| TCP_FLAG_PSH);
	276
	277	out_check_final:
	278	flush = len < mss;
	279	flush \|= (__force int)(flags & (TCP_FLAG_URG \| TCP_FLAG_PSH \|
	280	TCP_FLAG_RST \| TCP_FLAG_SYN \|
	281	TCP_FLAG_FIN));
	282
	283	if (p && (!NAPI_GRO_CB(skb)->same_flow \|\| flush))
d4546c25	284	pp = p;
28850dc7 DB	285
28850dc7 DB	286	out:
bf5a755f	287	NAPI_GRO_CB(skb)->flush \|= (flush != 0);
28850dc7 DB	288
	289	return pp;
	290	}
28850dc7 DB	291
	292	int tcp_gro_complete(struct sk_buff *skb)
	293	{
	294	struct tcphdr *th = tcp_hdr(skb);
	295
299603e8	296	skb->csum_start = (unsigned char *)th - skb->head;
28850dc7 DB	297	skb->csum_offset = offsetof(struct tcphdr, check);
	298	skb->ip_summed = CHECKSUM_PARTIAL;
	299
	300	skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
	301
	302	if (th->cwr)
	303	skb_shinfo(skb)->gso_type \|= SKB_GSO_TCP_ECN;
	304
	305	return 0;
	306	}
	307	EXPORT_SYMBOL(tcp_gro_complete);
	308
028e0a47 PA	309	INDIRECT_CALLABLE_SCOPE
028e0a47 PA	310	struct sk_buff tcp4_gro_receive(struct list_head head, struct sk_buff *skb)
28850dc7	311	{
cc5c00bb	312	/* Don't bother verifying checksum if we're going to flush anyway. */
149d0774 TH	313	if (!NAPI_GRO_CB(skb)->flush &&
	314	skb_gro_checksum_validate(skb, IPPROTO_TCP,
	315	inet_gro_compute_pseudo)) {
28850dc7 DB	316	NAPI_GRO_CB(skb)->flush = 1;
28850dc7 DB	317	return NULL;
28850dc7 DB	318	}
	319
	320	return tcp_gro_receive(head, skb);
	321	}
	322
028e0a47	323	INDIRECT_CALLABLE_SCOPE int tcp4_gro_complete(struct sk_buff *skb, int thoff)
28850dc7 DB	324	{
	325	const struct iphdr *iph = ip_hdr(skb);
	326	struct tcphdr *th = tcp_hdr(skb);
	327
299603e8 JC	328	th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr,
299603e8 JC	329	iph->daddr, 0);
c3caf119	330	skb_shinfo(skb)->gso_type \|= SKB_GSO_TCPV4;
28850dc7	331
1530545e AD	332	if (NAPI_GRO_CB(skb)->is_atomic)
	333	skb_shinfo(skb)->gso_type \|= SKB_GSO_TCP_FIXEDID;
	334
28850dc7 DB	335	return tcp_gro_complete(skb);
	336	}
	337
	338	static const struct net_offload tcpv4_offload = {
	339	.callbacks = {
d020f8f7	340	.gso_segment = tcp4_gso_segment,
28850dc7 DB	341	.gro_receive = tcp4_gro_receive,
	342	.gro_complete = tcp4_gro_complete,
	343	},
	344	};
	345
	346	int __init tcpv4_offload_init(void)
	347	{
	348	return inet_add_offload(&tcpv4_offload, IPPROTO_TCP);
	349	}