[people/ms/linux.git] / net / ipv4 / udp_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.
 *
 *	UDPv4 GSO support
 */

#include <linux/skbuff.h>
#include <net/udp.h>
#include <net/protocol.h>

static DEFINE_SPINLOCK(udp_offload_lock);
static struct udp_offload_priv __rcu *udp_offload_base __read_mostly;

#define udp_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&udp_offload_lock))

struct udp_offload_priv {
	struct udp_offload	*offload;
	struct rcu_head		rcu;
	struct udp_offload_priv __rcu *next;
};

static int udp4_ufo_send_check(struct sk_buff *skb)
{
	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
		return -EINVAL;

	if (likely(!skb->encapsulation)) {
		const struct iphdr *iph;
		struct udphdr *uh;

		iph = ip_hdr(skb);
		uh = udp_hdr(skb);

		uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
				IPPROTO_UDP, 0);
		skb->csum_start = skb_transport_header(skb) - skb->head;
		skb->csum_offset = offsetof(struct udphdr, check);
		skb->ip_summed = CHECKSUM_PARTIAL;
	}

	return 0;
}

struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
				       netdev_features_t features)
{
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	u16 mac_offset = skb->mac_header;
	int mac_len = skb->mac_len;
	int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
	__be16 protocol = skb->protocol;
	netdev_features_t enc_features;
	int udp_offset, outer_hlen;
	unsigned int oldlen;
	bool need_csum;

	oldlen = (u16)~skb->len;

	if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
		goto out;

	skb->encapsulation = 0;
	__skb_pull(skb, tnl_hlen);
	skb_reset_mac_header(skb);
	skb_set_network_header(skb, skb_inner_network_offset(skb));
	skb->mac_len = skb_inner_network_offset(skb);
	skb->protocol = htons(ETH_P_TEB);

	need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
	if (need_csum)
		skb->encap_hdr_csum = 1;

	/* segment inner packet. */
	enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
	segs = skb_mac_gso_segment(skb, enc_features);
	if (IS_ERR_OR_NULL(segs)) {
		skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
				     mac_len);
		goto out;
	}

	outer_hlen = skb_tnl_header_len(skb);
	udp_offset = outer_hlen - tnl_hlen;
	skb = segs;
	do {
		struct udphdr *uh;
		int len;

		skb_reset_inner_headers(skb);
		skb->encapsulation = 1;

		skb->mac_len = mac_len;

		skb_push(skb, outer_hlen);
		skb_reset_mac_header(skb);
		skb_set_network_header(skb, mac_len);
		skb_set_transport_header(skb, udp_offset);
		len = skb->len - udp_offset;
		uh = udp_hdr(skb);
		uh->len = htons(len);

		if (need_csum) {
			__be32 delta = htonl(oldlen + len);

			uh->check = ~csum_fold((__force __wsum)
					       ((__force u32)uh->check +
						(__force u32)delta));
			uh->check = gso_make_checksum(skb, ~uh->check);

			if (uh->check == 0)
				uh->check = CSUM_MANGLED_0;
		}

		skb->protocol = protocol;
	} while ((skb = skb->next));
out:
	return segs;
}

static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
					 netdev_features_t features)
{
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	unsigned int mss;
	int offset;
	__wsum csum;

	if (skb->encapsulation &&
	    (skb_shinfo(skb)->gso_type &
	     (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
		segs = skb_udp_tunnel_segment(skb, features);
		goto out;
	}

	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. */
		int type = skb_shinfo(skb)->gso_type;

		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
				      SKB_GSO_UDP_TUNNEL |
				      SKB_GSO_UDP_TUNNEL_CSUM |
				      SKB_GSO_IPIP |
				      SKB_GSO_GRE | SKB_GSO_GRE_CSUM |
				      SKB_GSO_MPLS) ||
			     !(type & (SKB_GSO_UDP))))
			goto out;

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

		segs = NULL;
		goto out;
	}

	/* Do software UFO. Complete and fill in the UDP checksum as
	 * HW cannot do checksum of UDP packets sent as multiple
	 * IP fragments.
	 */
	offset = skb_checksum_start_offset(skb);
	csum = skb_checksum(skb, offset, skb->len - offset, 0);
	offset += skb->csum_offset;
	*(__sum16 *)(skb->data + offset) = csum_fold(csum);
	skb->ip_summed = CHECKSUM_NONE;

	/* Fragment the skb. IP headers of the fragments are updated in
	 * inet_gso_segment()
	 */
	segs = skb_segment(skb, features);
out:
	return segs;
}

int udp_add_offload(struct udp_offload *uo)
{
	struct udp_offload_priv *new_offload = kzalloc(sizeof(*new_offload), GFP_ATOMIC);

	if (!new_offload)
		return -ENOMEM;

	new_offload->offload = uo;

	spin_lock(&udp_offload_lock);
	new_offload->next = udp_offload_base;
	rcu_assign_pointer(udp_offload_base, new_offload);
	spin_unlock(&udp_offload_lock);

	return 0;
}
EXPORT_SYMBOL(udp_add_offload);

static void udp_offload_free_routine(struct rcu_head *head)
{
	struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu);
	kfree(ou_priv);
}

void udp_del_offload(struct udp_offload *uo)
{
	struct udp_offload_priv __rcu **head = &udp_offload_base;
	struct udp_offload_priv *uo_priv;

	spin_lock(&udp_offload_lock);

	uo_priv = udp_deref_protected(*head);
	for (; uo_priv != NULL;
	     uo_priv = udp_deref_protected(*head)) {
		if (uo_priv->offload == uo) {
			rcu_assign_pointer(*head,
					   udp_deref_protected(uo_priv->next));
			goto unlock;
		}
		head = &uo_priv->next;
	}
	pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port));
unlock:
	spin_unlock(&udp_offload_lock);
	if (uo_priv != NULL)
		call_rcu(&uo_priv->rcu, udp_offload_free_routine);
}
EXPORT_SYMBOL(udp_del_offload);

struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,
				 struct udphdr *uh)
{
	struct udp_offload_priv *uo_priv;
	struct sk_buff *p, **pp = NULL;
	struct udphdr *uh2;
	unsigned int off = skb_gro_offset(skb);
	int flush = 1;

	if (NAPI_GRO_CB(skb)->udp_mark ||
	    (skb->ip_summed != CHECKSUM_PARTIAL &&
	     NAPI_GRO_CB(skb)->csum_cnt == 0 &&
	     !NAPI_GRO_CB(skb)->csum_valid))
		goto out;

	/* mark that this skb passed once through the udp gro layer */
	NAPI_GRO_CB(skb)->udp_mark = 1;

	rcu_read_lock();
	uo_priv = rcu_dereference(udp_offload_base);
	for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
		if (uo_priv->offload->port == uh->dest &&
		    uo_priv->offload->callbacks.gro_receive)
			goto unflush;
	}
	goto out_unlock;

unflush:
	flush = 0;

	for (p = *head; p; p = p->next) {
		if (!NAPI_GRO_CB(p)->same_flow)
			continue;

		uh2 = (struct udphdr   *)(p->data + off);

		/* Match ports and either checksums are either both zero
		 * or nonzero.
		 */
		if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
		    (!uh->check ^ !uh2->check)) {
			NAPI_GRO_CB(p)->same_flow = 0;
			continue;
		}
	}

	skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
	skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
	pp = uo_priv->offload->callbacks.gro_receive(head, skb);

out_unlock:
	rcu_read_unlock();
out:
	NAPI_GRO_CB(skb)->flush |= flush;
	return pp;
}

static struct sk_buff **udp4_gro_receive(struct sk_buff **head,
					 struct sk_buff *skb)
{
	struct udphdr *uh = udp_gro_udphdr(skb);

	/* Don't bother verifying checksum if we're going to flush anyway. */
	if (unlikely(!uh) ||
	    (!NAPI_GRO_CB(skb)->flush &&
	     skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
						  inet_gro_compute_pseudo))) {
		NAPI_GRO_CB(skb)->flush = 1;
		return NULL;
	}

	return udp_gro_receive(head, skb, uh);
}

int udp_gro_complete(struct sk_buff *skb, int nhoff)
{
	struct udp_offload_priv *uo_priv;
	__be16 newlen = htons(skb->len - nhoff);
	struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
	int err = -ENOSYS;

	uh->len = newlen;

	rcu_read_lock();

	uo_priv = rcu_dereference(udp_offload_base);
	for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
		if (uo_priv->offload->port == uh->dest &&
		    uo_priv->offload->callbacks.gro_complete)
			break;
	}

	if (uo_priv != NULL)
		err = uo_priv->offload->callbacks.gro_complete(skb, nhoff + sizeof(struct udphdr));

	rcu_read_unlock();
	return err;
}

int udp4_gro_complete(struct sk_buff *skb, int nhoff)
{
	const struct iphdr *iph = ip_hdr(skb);
	struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);

	if (uh->check)
		uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
					  iph->daddr, 0);

	return udp_gro_complete(skb, nhoff);
}

static const struct net_offload udpv4_offload = {
	.callbacks = {
		.gso_send_check = udp4_ufo_send_check,
		.gso_segment = udp4_ufo_fragment,
		.gro_receive  =	udp4_gro_receive,
		.gro_complete =	udp4_gro_complete,
	},
};

int __init udpv4_offload_init(void)
{
	return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
}
Commit	Line	Data
da5bab07 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	* UDPv4 GSO support
	11	*/
	12
	13	#include <linux/skbuff.h>
	14	#include <net/udp.h>
	15	#include <net/protocol.h>
	16
b582ef09	17	static DEFINE_SPINLOCK(udp_offload_lock);
a1d0cd8e	18	static struct udp_offload_priv __rcu *udp_offload_base __read_mostly;
b582ef09	19
a664a4f7 SP	20	#define udp_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&udp_offload_lock))
a664a4f7 SP	21
b582ef09 OG	22	struct udp_offload_priv {
	23	struct udp_offload *offload;
	24	struct rcu_head rcu;
	25	struct udp_offload_priv __rcu *next;
	26	};
	27
da5bab07 DB	28	static int udp4_ufo_send_check(struct sk_buff *skb)
	29	{
	30	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
	31	return -EINVAL;
	32
	33	if (likely(!skb->encapsulation)) {
	34	const struct iphdr *iph;
	35	struct udphdr *uh;
	36
	37	iph = ip_hdr(skb);
	38	uh = udp_hdr(skb);
	39
	40	uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
	41	IPPROTO_UDP, 0);
	42	skb->csum_start = skb_transport_header(skb) - skb->head;
	43	skb->csum_offset = offsetof(struct udphdr, check);
	44	skb->ip_summed = CHECKSUM_PARTIAL;
	45	}
	46
	47	return 0;
	48	}
	49
155e010e TH	50	struct sk_buff skb_udp_tunnel_segment(struct sk_buff skb,
	51	netdev_features_t features)
	52	{
	53	struct sk_buff *segs = ERR_PTR(-EINVAL);
	54	u16 mac_offset = skb->mac_header;
	55	int mac_len = skb->mac_len;
	56	int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
	57	__be16 protocol = skb->protocol;
	58	netdev_features_t enc_features;
	59	int udp_offset, outer_hlen;
	60	unsigned int oldlen;
	61	bool need_csum;
	62
	63	oldlen = (u16)~skb->len;
	64
	65	if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
	66	goto out;
	67
	68	skb->encapsulation = 0;
	69	__skb_pull(skb, tnl_hlen);
	70	skb_reset_mac_header(skb);
	71	skb_set_network_header(skb, skb_inner_network_offset(skb));
	72	skb->mac_len = skb_inner_network_offset(skb);
	73	skb->protocol = htons(ETH_P_TEB);
	74
	75	need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
	76	if (need_csum)
	77	skb->encap_hdr_csum = 1;
	78
	79	/* segment inner packet. */
	80	enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
	81	segs = skb_mac_gso_segment(skb, enc_features);
27446442	82	if (IS_ERR_OR_NULL(segs)) {
155e010e TH	83	skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
	84	mac_len);
	85	goto out;
	86	}
	87
	88	outer_hlen = skb_tnl_header_len(skb);
	89	udp_offset = outer_hlen - tnl_hlen;
	90	skb = segs;
	91	do {
	92	struct udphdr *uh;
	93	int len;
	94
	95	skb_reset_inner_headers(skb);
	96	skb->encapsulation = 1;
	97
	98	skb->mac_len = mac_len;
	99
	100	skb_push(skb, outer_hlen);
	101	skb_reset_mac_header(skb);
	102	skb_set_network_header(skb, mac_len);
	103	skb_set_transport_header(skb, udp_offset);
	104	len = skb->len - udp_offset;
	105	uh = udp_hdr(skb);
	106	uh->len = htons(len);
	107
	108	if (need_csum) {
	109	__be32 delta = htonl(oldlen + len);
	110
	111	uh->check = ~csum_fold((__force __wsum)
	112	((__force u32)uh->check +
	113	(__force u32)delta));
	114	uh->check = gso_make_checksum(skb, ~uh->check);
	115
	116	if (uh->check == 0)
	117	uh->check = CSUM_MANGLED_0;
	118	}
	119
	120	skb->protocol = protocol;
	121	} while ((skb = skb->next));
	122	out:
	123	return segs;
	124	}
	125
da5bab07 DB	126	static struct sk_buff udp4_ufo_fragment(struct sk_buff skb,
	127	netdev_features_t features)
	128	{
	129	struct sk_buff *segs = ERR_PTR(-EINVAL);
	130	unsigned int mss;
7a7ffbab WCC	131	int offset;
	132	__wsum csum;
	133
	134	if (skb->encapsulation &&
0f4f4ffa TH	135	(skb_shinfo(skb)->gso_type &
0f4f4ffa TH	136	(SKB_GSO_UDP_TUNNEL\|SKB_GSO_UDP_TUNNEL_CSUM))) {
7a7ffbab WCC	137	segs = skb_udp_tunnel_segment(skb, features);
	138	goto out;
	139	}
da5bab07 DB	140
	141	mss = skb_shinfo(skb)->gso_size;
	142	if (unlikely(skb->len <= mss))
	143	goto out;
	144
	145	if (skb_gso_ok(skb, features \| NETIF_F_GSO_ROBUST)) {
	146	/* Packet is from an untrusted source, reset gso_segs. */
	147	int type = skb_shinfo(skb)->gso_type;
	148
	149	if (unlikely(type & ~(SKB_GSO_UDP \| SKB_GSO_DODGY \|
	150	SKB_GSO_UDP_TUNNEL \|
0f4f4ffa	151	SKB_GSO_UDP_TUNNEL_CSUM \|
cb32f511	152	SKB_GSO_IPIP \|
4749c09c TH	153	SKB_GSO_GRE \| SKB_GSO_GRE_CSUM \|
4749c09c TH	154	SKB_GSO_MPLS) \|\|
da5bab07 DB	155	!(type & (SKB_GSO_UDP))))
	156	goto out;
	157
	158	skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
	159
	160	segs = NULL;
	161	goto out;
	162	}
	163
7a7ffbab WCC	164	/* Do software UFO. Complete and fill in the UDP checksum as
	165	* HW cannot do checksum of UDP packets sent as multiple
	166	* IP fragments.
	167	*/
	168	offset = skb_checksum_start_offset(skb);
	169	csum = skb_checksum(skb, offset, skb->len - offset, 0);
	170	offset += skb->csum_offset;
	171	(__sum16 )(skb->data + offset) = csum_fold(csum);
	172	skb->ip_summed = CHECKSUM_NONE;
	173
da5bab07 DB	174	/* Fragment the skb. IP headers of the fragments are updated in
	175	* inet_gso_segment()
	176	*/
7a7ffbab	177	segs = skb_segment(skb, features);
da5bab07 DB	178	out:
	179	return segs;
	180	}
	181
b582ef09 OG	182	int udp_add_offload(struct udp_offload *uo)
b582ef09 OG	183	{
b5aaab12	184	struct udp_offload_priv new_offload = kzalloc(sizeof(new_offload), GFP_ATOMIC);
b582ef09 OG	185
	186	if (!new_offload)
	187	return -ENOMEM;
	188
	189	new_offload->offload = uo;
	190
	191	spin_lock(&udp_offload_lock);
a664a4f7 SP	192	new_offload->next = udp_offload_base;
a664a4f7 SP	193	rcu_assign_pointer(udp_offload_base, new_offload);
b582ef09 OG	194	spin_unlock(&udp_offload_lock);
	195
	196	return 0;
	197	}
	198	EXPORT_SYMBOL(udp_add_offload);
	199
	200	static void udp_offload_free_routine(struct rcu_head *head)
	201	{
	202	struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu);
	203	kfree(ou_priv);
	204	}
	205
	206	void udp_del_offload(struct udp_offload *uo)
	207	{
	208	struct udp_offload_priv __rcu **head = &udp_offload_base;
	209	struct udp_offload_priv *uo_priv;
	210
	211	spin_lock(&udp_offload_lock);
	212
a664a4f7	213	uo_priv = udp_deref_protected(*head);
b582ef09	214	for (; uo_priv != NULL;
a664a4f7	215	uo_priv = udp_deref_protected(*head)) {
b582ef09	216	if (uo_priv->offload == uo) {
a664a4f7 SP	217	rcu_assign_pointer(*head,
a664a4f7 SP	218	udp_deref_protected(uo_priv->next));
b582ef09 OG	219	goto unlock;
	220	}
	221	head = &uo_priv->next;
	222	}
a1d0cd8e	223	pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port));
b582ef09 OG	224	unlock:
	225	spin_unlock(&udp_offload_lock);
	226	if (uo_priv != NULL)
	227	call_rcu(&uo_priv->rcu, udp_offload_free_routine);
	228	}
	229	EXPORT_SYMBOL(udp_del_offload);
	230
57c67ff4 TH	231	struct sk_buff udp_gro_receive(struct sk_buff head, struct sk_buff *skb,
57c67ff4 TH	232	struct udphdr *uh)
b582ef09 OG	233	{
	234	struct udp_offload_priv *uo_priv;
	235	struct sk_buff p, *pp = NULL;
57c67ff4 TH	236	struct udphdr *uh2;
57c67ff4 TH	237	unsigned int off = skb_gro_offset(skb);
b582ef09 OG	238	int flush = 1;
	239
	240	if (NAPI_GRO_CB(skb)->udp_mark \|\|
662880f4 TH	241	(skb->ip_summed != CHECKSUM_PARTIAL &&
	242	NAPI_GRO_CB(skb)->csum_cnt == 0 &&
	243	!NAPI_GRO_CB(skb)->csum_valid))
b582ef09 OG	244	goto out;
	245
	246	/* mark that this skb passed once through the udp gro layer */
	247	NAPI_GRO_CB(skb)->udp_mark = 1;
b582ef09 OG	248
	249	rcu_read_lock();
	250	uo_priv = rcu_dereference(udp_offload_base);
	251	for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
	252	if (uo_priv->offload->port == uh->dest &&
	253	uo_priv->offload->callbacks.gro_receive)
	254	goto unflush;
	255	}
	256	goto out_unlock;
	257
	258	unflush:
	259	flush = 0;
	260
	261	for (p = *head; p; p = p->next) {
	262	if (!NAPI_GRO_CB(p)->same_flow)
	263	continue;
	264
	265	uh2 = (struct udphdr *)(p->data + off);
57c67ff4 TH	266
	267	/* Match ports and either checksums are either both zero
	268	* or nonzero.
	269	*/
	270	if (((u32 )&uh->source != (u32 )&uh2->source) \|\|
	271	(!uh->check ^ !uh2->check)) {
b582ef09 OG	272	NAPI_GRO_CB(p)->same_flow = 0;
	273	continue;
	274	}
	275	}
	276
	277	skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
6bae1d4c	278	skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
b582ef09 OG	279	pp = uo_priv->offload->callbacks.gro_receive(head, skb);
	280
	281	out_unlock:
	282	rcu_read_unlock();
	283	out:
	284	NAPI_GRO_CB(skb)->flush \|= flush;
	285	return pp;
	286	}
	287
57c67ff4 TH	288	static struct sk_buff udp4_gro_receive(struct sk_buff head,
	289	struct sk_buff *skb)
	290	{
	291	struct udphdr *uh = udp_gro_udphdr(skb);
	292
	293	/* Don't bother verifying checksum if we're going to flush anyway. */
	294	if (unlikely(!uh) \|\|
	295	(!NAPI_GRO_CB(skb)->flush &&
	296	skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
	297	inet_gro_compute_pseudo))) {
	298	NAPI_GRO_CB(skb)->flush = 1;
	299	return NULL;
	300	}
	301
	302	return udp_gro_receive(head, skb, uh);
	303	}
	304
	305	int udp_gro_complete(struct sk_buff *skb, int nhoff)
b582ef09 OG	306	{
	307	struct udp_offload_priv *uo_priv;
	308	__be16 newlen = htons(skb->len - nhoff);
	309	struct udphdr uh = (struct udphdr )(skb->data + nhoff);
	310	int err = -ENOSYS;
	311
	312	uh->len = newlen;
	313
	314	rcu_read_lock();
	315
	316	uo_priv = rcu_dereference(udp_offload_base);
	317	for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
	318	if (uo_priv->offload->port == uh->dest &&
	319	uo_priv->offload->callbacks.gro_complete)
	320	break;
	321	}
	322
	323	if (uo_priv != NULL)
	324	err = uo_priv->offload->callbacks.gro_complete(skb, nhoff + sizeof(struct udphdr));
	325
	326	rcu_read_unlock();
	327	return err;
	328	}
	329
57c67ff4 TH	330	int udp4_gro_complete(struct sk_buff *skb, int nhoff)
	331	{
	332	const struct iphdr *iph = ip_hdr(skb);
	333	struct udphdr uh = (struct udphdr )(skb->data + nhoff);
	334
	335	if (uh->check)
	336	uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
	337	iph->daddr, 0);
	338
	339	return udp_gro_complete(skb, nhoff);
	340	}
	341
da5bab07 DB	342	static const struct net_offload udpv4_offload = {
	343	.callbacks = {
	344	.gso_send_check = udp4_ufo_send_check,
	345	.gso_segment = udp4_ufo_fragment,
57c67ff4 TH	346	.gro_receive = udp4_gro_receive,
57c67ff4 TH	347	.gro_complete = udp4_gro_complete,
da5bab07 DB	348	},
	349	};
	350
	351	int __init udpv4_offload_init(void)
	352	{
	353	return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
	354	}