Release 4.11 net/ipv4/gre_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.
 *
 *      GRE GSO support
 */

#include <linux/skbuff.h>
#include <linux/init.h>
#include <net/protocol.h>
#include <net/gre.h>



static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
				       netdev_features_t features)
{
	int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	u16 mac_offset = skb->mac_header;
	__be16 protocol = skb->protocol;
	u16 mac_len = skb->mac_len;
	int gre_offset, outer_hlen;
	bool need_csum, ufo, gso_partial;

	if (!skb->encapsulation)
		goto out;

	if (unlikely(tnl_hlen < sizeof(struct gre_base_hdr)))
		goto out;

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

	/* setup inner skb. */
	skb->encapsulation = 0;
	SKB_GSO_CB(skb)->encap_level = 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 = skb->inner_protocol;

	need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_GRE_CSUM);
	skb->encap_hdr_csum = need_csum;

	ufo = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);

	features &= skb->dev->hw_enc_features;

	/* The only checksum offload we care about from here on out is the
         * outer one so strip the existing checksum feature flags based
         * on the fact that we will be computing our checksum in software.
         */
	if (ufo) {
		features &= ~NETIF_F_CSUM_MASK;
		if (!need_csum)
			features |= NETIF_F_HW_CSUM;
	}

	/* segment inner packet. */
	segs = skb_mac_gso_segment(skb, features);
	if (IS_ERR_OR_NULL(segs)) {
		skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
				     mac_len);
		goto out;
	}

	gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);

	outer_hlen = skb_tnl_header_len(skb);
	gre_offset = outer_hlen - tnl_hlen;
	skb = segs;
	do {
		struct gre_base_hdr *greh;
		__sum16 *pcsum;

		/* Set up inner headers if we are offloading inner checksum */
		if (skb->ip_summed == CHECKSUM_PARTIAL) {
			skb_reset_inner_headers(skb);
			skb->encapsulation = 1;
		}

		skb->mac_len = mac_len;
		skb->protocol = protocol;

		__skb_push(skb, outer_hlen);
		skb_reset_mac_header(skb);
		skb_set_network_header(skb, mac_len);
		skb_set_transport_header(skb, gre_offset);

		if (!need_csum)
			continue;

		greh = (struct gre_base_hdr *)skb_transport_header(skb);
		pcsum = (__sum16 *)(greh + 1);

		if (gso_partial) {
			unsigned int partial_adj;

			/* Adjust checksum to account for the fact that
                         * the partial checksum is based on actual size
                         * whereas headers should be based on MSS size.
                         */
			partial_adj = skb->len + skb_headroom(skb) -
				      SKB_GSO_CB(skb)->data_offset -
				      skb_shinfo(skb)->gso_size;
			*pcsum = ~csum_fold((__force __wsum)htonl(partial_adj));
		} else {
			*pcsum = 0;
		}

		*(pcsum + 1) = 0;
		*pcsum = gso_make_checksum(skb, 0);
	} while ((skb = skb->next));
out:
	return segs;
}

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Alexander Duyck
252
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Daniel Borkmann
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34.87%
1
7.14%
Wei-Chun Chao
21
4.21%
1
7.14%
Steffen Klassert
18
3.61%
1
7.14%
Tom Herbert
18
3.61%
2
14.29%
Neal Cardwell
8
1.60%
1
7.14%
Li RongQing
7
1.40%
1
7.14%
Himangi Saraogi
1
0.20%
1
7.14%
Total
499
100.00%
14
100.00%



static struct sk_buff **gre_gro_receive(struct sk_buff **head,
					struct sk_buff *skb)
{
	struct sk_buff **pp = NULL;
	struct sk_buff *p;
	const struct gre_base_hdr *greh;
	unsigned int hlen, grehlen;
	unsigned int off;
	int flush = 1;
	struct packet_offload *ptype;
	__be16 type;

	if (NAPI_GRO_CB(skb)->encap_mark)
		goto out;

	NAPI_GRO_CB(skb)->encap_mark = 1;

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

	/* Only support version 0 and K (key), C (csum) flags. Note that
         * although the support for the S (seq#) flag can be added easily
         * for GRO, this is problematic for GSO hence can not be enabled
         * here because a GRO pkt may end up in the forwarding path, thus
         * requiring GSO support to break it up correctly.
         */
	if ((greh->flags & ~(GRE_KEY|GRE_CSUM)) != 0)
		goto out;

	/* We can only support GRE_CSUM if we can track the location of
         * the GRE header.  In the case of FOU/GUE we cannot because the
         * outer UDP header displaces the GRE header leaving us in a state
         * of limbo.
         */
	if ((greh->flags & GRE_CSUM) && NAPI_GRO_CB(skb)->is_fou)
		goto out;

	type = greh->protocol;

	rcu_read_lock();
	ptype = gro_find_receive_by_type(type);
	if (!ptype)
		goto out_unlock;

	grehlen = GRE_HEADER_SECTION;

	if (greh->flags & GRE_KEY)
		grehlen += GRE_HEADER_SECTION;

	if (greh->flags & GRE_CSUM)
		grehlen += GRE_HEADER_SECTION;

	hlen = off + grehlen;
	if (skb_gro_header_hard(skb, hlen)) {
		greh = skb_gro_header_slow(skb, hlen, off);
		if (unlikely(!greh))
			goto out_unlock;
	}

	/* Don't bother verifying checksum if we're going to flush anyway. */
	if ((greh->flags & GRE_CSUM) && !NAPI_GRO_CB(skb)->flush) {
		if (skb_gro_checksum_simple_validate(skb))
			goto out_unlock;

		skb_gro_checksum_try_convert(skb, IPPROTO_GRE, 0,
					     null_compute_pseudo);
	}

	for (p = *head; p; p = p->next) {
		const struct gre_base_hdr *greh2;

		if (!NAPI_GRO_CB(p)->same_flow)
			continue;

		/* The following checks are needed to ensure only pkts
                 * from the same tunnel are considered for aggregation.
                 * The criteria for "the same tunnel" includes:
                 * 1) same version (we only support version 0 here)
                 * 2) same protocol (we only support ETH_P_IP for now)
                 * 3) same set of flags
                 * 4) same key if the key field is present.
                 */
		greh2 = (struct gre_base_hdr *)(p->data + off);

		if (greh2->flags != greh->flags ||
		    greh2->protocol != greh->protocol) {
			NAPI_GRO_CB(p)->same_flow = 0;
			continue;
		}
		if (greh->flags & GRE_KEY) {
			/* compare keys */
			if (*(__be32 *)(greh2+1) != *(__be32 *)(greh+1)) {
				NAPI_GRO_CB(p)->same_flow = 0;
				continue;
			}
		}
	}

	skb_gro_pull(skb, grehlen);

	/* Adjusted NAPI_GRO_CB(skb)->csum after skb_gro_pull()*/
	skb_gro_postpull_rcsum(skb, greh, grehlen);

	pp = call_gro_receive(ptype->callbacks.gro_receive, head, skb);
	flush = 0;

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

	return pp;
}

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Jerry Chu
426
85.37%
1
11.11%
Alexander Duyck
25
5.01%
2
22.22%
Tom Herbert
23
4.61%
3
33.33%
Jesse Gross
21
4.21%
1
11.11%
Sabrina Dubroca
3
0.60%
1
11.11%
Ian Morris
1
0.20%
1
11.11%
Total
499
100.00%
9
100.00%



static int gre_gro_complete(struct sk_buff *skb, int nhoff)
{
	struct gre_base_hdr *greh = (struct gre_base_hdr *)(skb->data + nhoff);
	struct packet_offload *ptype;
	unsigned int grehlen = sizeof(*greh);
	int err = -ENOENT;
	__be16 type;

	skb->encapsulation = 1;
	skb_shinfo(skb)->gso_type = SKB_GSO_GRE;

	type = greh->protocol;
	if (greh->flags & GRE_KEY)
		grehlen += GRE_HEADER_SECTION;

	if (greh->flags & GRE_CSUM)
		grehlen += GRE_HEADER_SECTION;

	rcu_read_lock();
	ptype = gro_find_complete_by_type(type);
	if (ptype)
		err = ptype->callbacks.gro_complete(skb, nhoff + grehlen);

	rcu_read_unlock();

	skb_set_inner_mac_header(skb, nhoff + grehlen);

	return err;
}

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25.00%
Wei Yongjun
1
0.69%
1
25.00%
Total
145
100.00%
4
100.00%


static const struct net_offload gre_offload = {
	.callbacks = {
		.gso_segment = gre_gso_segment,
		.gro_receive = gre_gro_receive,
		.gro_complete = gre_gro_complete,
        },
};



static int __init gre_offload_init(void)
{
	int err;

	err = inet_add_offload(&gre_offload, IPPROTO_GRE);
#if IS_ENABLED(CONFIG_IPV6)
	if (err)
		return err;

	err = inet6_add_offload(&gre_offload, IPPROTO_GRE);
	if (err)
		inet_del_offload(&gre_offload, IPPROTO_GRE);
#endif

	return err;
}
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Eric Dumazet
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1.61%
1
33.33%
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3
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device_initcall(gre_offload_init);
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322
25.74%
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31.03%
Daniel Borkmann
218
17.43%
1
3.45%
Tom Herbert
50
4.00%
6
20.69%
Jesse Gross
21
1.68%
1
3.45%
Wei-Chun Chao
21
1.68%
1
3.45%
Steffen Klassert
18
1.44%
1
3.45%
Neal Cardwell
8
0.64%
1
3.45%
Li RongQing
7
0.56%
1
3.45%
Eric Dumazet
5
0.40%
1
3.45%
Paul Gortmaker
4
0.32%
1
3.45%
Sabrina Dubroca
3
0.24%
1
3.45%
Wei Yongjun
1
0.08%
1
3.45%
Himangi Saraogi
1
0.08%
1
3.45%
Ian Morris
1
0.08%
1
3.45%
Total
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29
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Directory: net/ipv4

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