[deliverable/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 struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
	netdev_features_t features,
	struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
					     netdev_features_t features),
	__be16 new_protocol)
{
	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 = new_protocol;

	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 = gso_inner_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;
}

struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
				       netdev_features_t features,
				       bool is_ipv6)
{
	__be16 protocol = skb->protocol;
	const struct net_offload **offloads;
	const struct net_offload *ops;
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
					     netdev_features_t features);

	rcu_read_lock();

	switch (skb->inner_protocol_type) {
	case ENCAP_TYPE_ETHER:
		protocol = skb->inner_protocol;
		gso_inner_segment = skb_mac_gso_segment;
		break;
	case ENCAP_TYPE_IPPROTO:
		offloads = is_ipv6 ? inet6_offloads : inet_offloads;
		ops = rcu_dereference(offloads[skb->inner_ipproto]);
		if (!ops || !ops->callbacks.gso_segment)
			goto out_unlock;
		gso_inner_segment = ops->callbacks.gso_segment;
		break;
	default:
		goto out_unlock;
	}

	segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
					protocol);

out_unlock:
	rcu_read_unlock();

	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;
	__wsum csum;
	struct udphdr *uh;
	struct iphdr *iph;

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

	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
		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.
	 */

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

	uh->check = 0;
	csum = skb_checksum(skb, 0, skb->len, 0);
	uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
	if (uh->check == 0)
		uh->check = CSUM_MANGLED_0;

	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));
	NAPI_GRO_CB(skb)->proto = uo_priv->offload->ipproto;
	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);

	if (unlikely(!uh))
		goto flush;

	/* Don't bother verifying checksum if we're going to flush anyway. */
	if (NAPI_GRO_CB(skb)->flush)
		goto skip;

	if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
						 inet_gro_compute_pseudo))
		goto flush;
	else if (uh->check)
		skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
					     inet_gro_compute_pseudo);
skip:
	return udp_gro_receive(head, skb, uh);

flush:
	NAPI_GRO_CB(skb)->flush = 1;
	return NULL;
}

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) {
		NAPI_GRO_CB(skb)->proto = uo_priv->offload->ipproto;
		err = uo_priv->offload->callbacks.gro_complete(skb, nhoff + sizeof(struct udphdr));
	}

	rcu_read_unlock();
	return err;
}

static 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_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
8bce6d7d TH	28	static struct sk_buff __skb_udp_tunnel_segment(struct sk_buff skb,
	29	netdev_features_t features,
	30	struct sk_buff (gso_inner_segment)(struct sk_buff *skb,
	31	netdev_features_t features),
	32	__be16 new_protocol)
155e010e TH	33	{
	34	struct sk_buff *segs = ERR_PTR(-EINVAL);
	35	u16 mac_offset = skb->mac_header;
	36	int mac_len = skb->mac_len;
	37	int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
	38	__be16 protocol = skb->protocol;
	39	netdev_features_t enc_features;
	40	int udp_offset, outer_hlen;
	41	unsigned int oldlen;
	42	bool need_csum;
	43
	44	oldlen = (u16)~skb->len;
	45
	46	if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
	47	goto out;
	48
	49	skb->encapsulation = 0;
	50	__skb_pull(skb, tnl_hlen);
	51	skb_reset_mac_header(skb);
	52	skb_set_network_header(skb, skb_inner_network_offset(skb));
	53	skb->mac_len = skb_inner_network_offset(skb);
8bce6d7d	54	skb->protocol = new_protocol;
155e010e TH	55
	56	need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
	57	if (need_csum)
	58	skb->encap_hdr_csum = 1;
	59
	60	/* segment inner packet. */
	61	enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
8bce6d7d	62	segs = gso_inner_segment(skb, enc_features);
27446442	63	if (IS_ERR_OR_NULL(segs)) {
155e010e TH	64	skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
	65	mac_len);
	66	goto out;
	67	}
	68
	69	outer_hlen = skb_tnl_header_len(skb);
	70	udp_offset = outer_hlen - tnl_hlen;
	71	skb = segs;
	72	do {
	73	struct udphdr *uh;
	74	int len;
	75
	76	skb_reset_inner_headers(skb);
	77	skb->encapsulation = 1;
	78
	79	skb->mac_len = mac_len;
	80
	81	skb_push(skb, outer_hlen);
	82	skb_reset_mac_header(skb);
	83	skb_set_network_header(skb, mac_len);
	84	skb_set_transport_header(skb, udp_offset);
	85	len = skb->len - udp_offset;
	86	uh = udp_hdr(skb);
	87	uh->len = htons(len);
	88
	89	if (need_csum) {
	90	__be32 delta = htonl(oldlen + len);
	91
	92	uh->check = ~csum_fold((__force __wsum)
	93	((__force u32)uh->check +
	94	(__force u32)delta));
	95	uh->check = gso_make_checksum(skb, ~uh->check);
	96
	97	if (uh->check == 0)
	98	uh->check = CSUM_MANGLED_0;
	99	}
	100
	101	skb->protocol = protocol;
	102	} while ((skb = skb->next));
	103	out:
	104	return segs;
	105	}
	106
8bce6d7d TH	107	struct sk_buff skb_udp_tunnel_segment(struct sk_buff skb,
	108	netdev_features_t features,
	109	bool is_ipv6)
	110	{
	111	__be16 protocol = skb->protocol;
	112	const struct net_offload **offloads;
	113	const struct net_offload *ops;
	114	struct sk_buff *segs = ERR_PTR(-EINVAL);
	115	struct sk_buff (gso_inner_segment)(struct sk_buff *skb,
	116	netdev_features_t features);
	117
	118	rcu_read_lock();
	119
	120	switch (skb->inner_protocol_type) {
	121	case ENCAP_TYPE_ETHER:
	122	protocol = skb->inner_protocol;
	123	gso_inner_segment = skb_mac_gso_segment;
	124	break;
	125	case ENCAP_TYPE_IPPROTO:
	126	offloads = is_ipv6 ? inet6_offloads : inet_offloads;
	127	ops = rcu_dereference(offloads[skb->inner_ipproto]);
	128	if (!ops \|\| !ops->callbacks.gso_segment)
	129	goto out_unlock;
	130	gso_inner_segment = ops->callbacks.gso_segment;
	131	break;
	132	default:
	133	goto out_unlock;
	134	}
	135
	136	segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
	137	protocol);
	138
	139	out_unlock:
	140	rcu_read_unlock();
	141
	142	return segs;
	143	}
	144
da5bab07 DB	145	static struct sk_buff udp4_ufo_fragment(struct sk_buff skb,
	146	netdev_features_t features)
	147	{
	148	struct sk_buff *segs = ERR_PTR(-EINVAL);
	149	unsigned int mss;
7a7ffbab	150	__wsum csum;
f71470b3 TH	151	struct udphdr *uh;
f71470b3 TH	152	struct iphdr *iph;
7a7ffbab WCC	153
7a7ffbab WCC	154	if (skb->encapsulation &&
0f4f4ffa TH	155	(skb_shinfo(skb)->gso_type &
0f4f4ffa TH	156	(SKB_GSO_UDP_TUNNEL\|SKB_GSO_UDP_TUNNEL_CSUM))) {
8bce6d7d	157	segs = skb_udp_tunnel_segment(skb, features, false);
7a7ffbab WCC	158	goto out;
7a7ffbab WCC	159	}
da5bab07	160
f71470b3 TH	161	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
	162	goto out;
	163
da5bab07 DB	164	mss = skb_shinfo(skb)->gso_size;
	165	if (unlikely(skb->len <= mss))
	166	goto out;
	167
	168	if (skb_gso_ok(skb, features \| NETIF_F_GSO_ROBUST)) {
	169	/* Packet is from an untrusted source, reset gso_segs. */
	170	int type = skb_shinfo(skb)->gso_type;
	171
	172	if (unlikely(type & ~(SKB_GSO_UDP \| SKB_GSO_DODGY \|
	173	SKB_GSO_UDP_TUNNEL \|
0f4f4ffa	174	SKB_GSO_UDP_TUNNEL_CSUM \|
cb32f511	175	SKB_GSO_IPIP \|
4749c09c TH	176	SKB_GSO_GRE \| SKB_GSO_GRE_CSUM \|
4749c09c TH	177	SKB_GSO_MPLS) \|\|
da5bab07 DB	178	!(type & (SKB_GSO_UDP))))
	179	goto out;
	180
	181	skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
	182
	183	segs = NULL;
	184	goto out;
	185	}
	186
7a7ffbab WCC	187	/* Do software UFO. Complete and fill in the UDP checksum as
	188	* HW cannot do checksum of UDP packets sent as multiple
	189	* IP fragments.
	190	*/
f71470b3 TH	191
	192	uh = udp_hdr(skb);
	193	iph = ip_hdr(skb);
	194
	195	uh->check = 0;
	196	csum = skb_checksum(skb, 0, skb->len, 0);
	197	uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
	198	if (uh->check == 0)
	199	uh->check = CSUM_MANGLED_0;
	200
7a7ffbab WCC	201	skb->ip_summed = CHECKSUM_NONE;
7a7ffbab WCC	202
da5bab07 DB	203	/* Fragment the skb. IP headers of the fragments are updated in
	204	* inet_gso_segment()
	205	*/
7a7ffbab	206	segs = skb_segment(skb, features);
da5bab07 DB	207	out:
	208	return segs;
	209	}
	210
b582ef09 OG	211	int udp_add_offload(struct udp_offload *uo)
b582ef09 OG	212	{
b5aaab12	213	struct udp_offload_priv new_offload = kzalloc(sizeof(new_offload), GFP_ATOMIC);
b582ef09 OG	214
	215	if (!new_offload)
	216	return -ENOMEM;
	217
	218	new_offload->offload = uo;
	219
	220	spin_lock(&udp_offload_lock);
a664a4f7 SP	221	new_offload->next = udp_offload_base;
a664a4f7 SP	222	rcu_assign_pointer(udp_offload_base, new_offload);
b582ef09 OG	223	spin_unlock(&udp_offload_lock);
	224
	225	return 0;
	226	}
	227	EXPORT_SYMBOL(udp_add_offload);
	228
	229	static void udp_offload_free_routine(struct rcu_head *head)
	230	{
	231	struct udp_offload_priv *ou_priv = container_of(head, struct udp_offload_priv, rcu);
	232	kfree(ou_priv);
	233	}
	234
	235	void udp_del_offload(struct udp_offload *uo)
	236	{
	237	struct udp_offload_priv __rcu **head = &udp_offload_base;
	238	struct udp_offload_priv *uo_priv;
	239
	240	spin_lock(&udp_offload_lock);
	241
a664a4f7	242	uo_priv = udp_deref_protected(*head);
b582ef09	243	for (; uo_priv != NULL;
a664a4f7	244	uo_priv = udp_deref_protected(*head)) {
b582ef09	245	if (uo_priv->offload == uo) {
a664a4f7 SP	246	rcu_assign_pointer(*head,
a664a4f7 SP	247	udp_deref_protected(uo_priv->next));
b582ef09 OG	248	goto unlock;
	249	}
	250	head = &uo_priv->next;
	251	}
a1d0cd8e	252	pr_warn("udp_del_offload: didn't find offload for port %d\n", ntohs(uo->port));
b582ef09 OG	253	unlock:
	254	spin_unlock(&udp_offload_lock);
	255	if (uo_priv != NULL)
	256	call_rcu(&uo_priv->rcu, udp_offload_free_routine);
	257	}
	258	EXPORT_SYMBOL(udp_del_offload);
	259
57c67ff4 TH	260	struct sk_buff udp_gro_receive(struct sk_buff head, struct sk_buff *skb,
57c67ff4 TH	261	struct udphdr *uh)
b582ef09 OG	262	{
	263	struct udp_offload_priv *uo_priv;
	264	struct sk_buff p, *pp = NULL;
57c67ff4 TH	265	struct udphdr *uh2;
57c67ff4 TH	266	unsigned int off = skb_gro_offset(skb);
b582ef09 OG	267	int flush = 1;
	268
	269	if (NAPI_GRO_CB(skb)->udp_mark \|\|
662880f4 TH	270	(skb->ip_summed != CHECKSUM_PARTIAL &&
	271	NAPI_GRO_CB(skb)->csum_cnt == 0 &&
	272	!NAPI_GRO_CB(skb)->csum_valid))
b582ef09 OG	273	goto out;
	274
	275	/* mark that this skb passed once through the udp gro layer */
	276	NAPI_GRO_CB(skb)->udp_mark = 1;
b582ef09 OG	277
	278	rcu_read_lock();
	279	uo_priv = rcu_dereference(udp_offload_base);
	280	for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
	281	if (uo_priv->offload->port == uh->dest &&
	282	uo_priv->offload->callbacks.gro_receive)
	283	goto unflush;
	284	}
	285	goto out_unlock;
	286
	287	unflush:
	288	flush = 0;
	289
	290	for (p = *head; p; p = p->next) {
	291	if (!NAPI_GRO_CB(p)->same_flow)
	292	continue;
	293
	294	uh2 = (struct udphdr *)(p->data + off);
57c67ff4 TH	295
	296	/* Match ports and either checksums are either both zero
	297	* or nonzero.
	298	*/
	299	if (((u32 )&uh->source != (u32 )&uh2->source) \|\|
	300	(!uh->check ^ !uh2->check)) {
b582ef09 OG	301	NAPI_GRO_CB(p)->same_flow = 0;
	302	continue;
	303	}
	304	}
	305
	306	skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
6bae1d4c	307	skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
afe93325	308	NAPI_GRO_CB(skb)->proto = uo_priv->offload->ipproto;
b582ef09 OG	309	pp = uo_priv->offload->callbacks.gro_receive(head, skb);
	310
	311	out_unlock:
	312	rcu_read_unlock();
	313	out:
	314	NAPI_GRO_CB(skb)->flush \|= flush;
	315	return pp;
	316	}
	317
57c67ff4 TH	318	static struct sk_buff udp4_gro_receive(struct sk_buff head,
	319	struct sk_buff *skb)
	320	{
	321	struct udphdr *uh = udp_gro_udphdr(skb);
	322
2abb7cdc TH	323	if (unlikely(!uh))
2abb7cdc TH	324	goto flush;
57c67ff4	325
2abb7cdc	326	/* Don't bother verifying checksum if we're going to flush anyway. */
2d8f7e2c	327	if (NAPI_GRO_CB(skb)->flush)
2abb7cdc TH	328	goto skip;
	329
	330	if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
	331	inet_gro_compute_pseudo))
	332	goto flush;
	333	else if (uh->check)
	334	skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
	335	inet_gro_compute_pseudo);
	336	skip:
57c67ff4	337	return udp_gro_receive(head, skb, uh);
2abb7cdc TH	338
	339	flush:
	340	NAPI_GRO_CB(skb)->flush = 1;
	341	return NULL;
57c67ff4 TH	342	}
	343
	344	int udp_gro_complete(struct sk_buff *skb, int nhoff)
b582ef09 OG	345	{
	346	struct udp_offload_priv *uo_priv;
	347	__be16 newlen = htons(skb->len - nhoff);
	348	struct udphdr uh = (struct udphdr )(skb->data + nhoff);
	349	int err = -ENOSYS;
	350
	351	uh->len = newlen;
	352
	353	rcu_read_lock();
	354
	355	uo_priv = rcu_dereference(udp_offload_base);
	356	for (; uo_priv != NULL; uo_priv = rcu_dereference(uo_priv->next)) {
	357	if (uo_priv->offload->port == uh->dest &&
	358	uo_priv->offload->callbacks.gro_complete)
	359	break;
	360	}
	361
afe93325 TH	362	if (uo_priv != NULL) {
afe93325 TH	363	NAPI_GRO_CB(skb)->proto = uo_priv->offload->ipproto;
b582ef09	364	err = uo_priv->offload->callbacks.gro_complete(skb, nhoff + sizeof(struct udphdr));
afe93325	365	}
b582ef09 OG	366
	367	rcu_read_unlock();
	368	return err;
	369	}
	370
72bb17b3	371	static int udp4_gro_complete(struct sk_buff *skb, int nhoff)
57c67ff4 TH	372	{
	373	const struct iphdr *iph = ip_hdr(skb);
	374	struct udphdr uh = (struct udphdr )(skb->data + nhoff);
	375
	376	if (uh->check)
	377	uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
	378	iph->daddr, 0);
	379
	380	return udp_gro_complete(skb, nhoff);
	381	}
	382
da5bab07 DB	383	static const struct net_offload udpv4_offload = {
da5bab07 DB	384	.callbacks = {
da5bab07	385	.gso_segment = udp4_ufo_fragment,
57c67ff4 TH	386	.gro_receive = udp4_gro_receive,
57c67ff4 TH	387	.gro_complete = udp4_gro_complete,
da5bab07 DB	388	},
	389	};
	390
	391	int __init udpv4_offload_init(void)
	392	{
	393	return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
	394	}