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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/net/mpls/mpls_gso.c
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// SPDX-License-Identifier: GPL-2.0-or-later

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/*

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 *	MPLS GSO Support

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 *

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 *	Authors: Simon Horman ([email protected])

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 *

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 *	Based on: GSO portions of net/ipv4/gre.c

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 */

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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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#include <linux/err.h>

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#include <linux/module.h>

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#include <linux/netdev_features.h>

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#include <linux/netdevice.h>

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#include <linux/skbuff.h>

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#include <net/gso.h>

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#include <net/mpls.h>

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static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,

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				       netdev_features_t features)

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{

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	struct sk_buff *segs = ERR_PTR(-EINVAL);

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	u16 mac_offset = skb->mac_header;

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	netdev_features_t mpls_features;

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	u16 mac_len = skb->mac_len;

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	__be16 mpls_protocol;

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	unsigned int mpls_hlen;

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	if (!skb_inner_network_header_was_set(skb))

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		goto out;

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	skb_reset_network_header(skb);

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	mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb);

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	if (unlikely(!mpls_hlen || mpls_hlen % MPLS_HLEN))

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		goto out;

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	if (unlikely(!pskb_may_pull(skb, mpls_hlen)))

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		goto out;

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	/* Setup inner SKB. */

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	mpls_protocol = skb->protocol;

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	skb->protocol = skb->inner_protocol;

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	__skb_pull(skb, mpls_hlen);

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	skb->mac_len = 0;

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	skb_reset_mac_header(skb);

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	/* Segment inner packet. */

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	mpls_features = skb->dev->mpls_features & features;

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	segs = skb_mac_gso_segment(skb, mpls_features);

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	if (IS_ERR_OR_NULL(segs)) {

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		skb_gso_error_unwind(skb, mpls_protocol, mpls_hlen, mac_offset,

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				     mac_len);

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		goto out;

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	}

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	skb = segs;

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	mpls_hlen += mac_len;

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	do {

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		skb->mac_len = mac_len;

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		skb->protocol = mpls_protocol;

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		skb_reset_inner_network_header(skb);

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		__skb_push(skb, mpls_hlen);

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		skb_reset_mac_header(skb);

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		skb_set_network_header(skb, mac_len);

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	} while ((skb = skb->next));

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out:

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	return segs;

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}

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static struct packet_offload mpls_mc_offload __read_mostly = {

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	.type = cpu_to_be16(ETH_P_MPLS_MC),

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	.priority = 15,

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	.callbacks = {

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		.gso_segment    =	mpls_gso_segment,

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	},

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};

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static struct packet_offload mpls_uc_offload __read_mostly = {

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	.type = cpu_to_be16(ETH_P_MPLS_UC),

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	.priority = 15,

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	.callbacks = {

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		.gso_segment    =	mpls_gso_segment,

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	},

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};

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static int __init mpls_gso_init(void)

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{

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	pr_info("MPLS GSO support\n");

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	dev_add_offload(&mpls_uc_offload);

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	dev_add_offload(&mpls_mc_offload);

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	return 0;

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}

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static void __exit mpls_gso_exit(void)

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{

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	dev_remove_offload(&mpls_uc_offload);

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	dev_remove_offload(&mpls_mc_offload);

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}

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module_init(mpls_gso_init);

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module_exit(mpls_gso_exit);

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MODULE_DESCRIPTION("MPLS GSO support");

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MODULE_AUTHOR("Simon Horman <[email protected]>");

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MODULE_LICENSE("GPL");

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