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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/net/ipv6/xfrm6_mode_tunnel.c
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/*

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 * xfrm6_mode_tunnel.c - Tunnel mode encapsulation for IPv6.

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 *

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 * Copyright (C) 2002 USAGI/WIDE Project

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 * Copyright (c) 2004-2006 Herbert Xu <[email protected]>

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 */

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#include <linux/gfp.h>

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#include <linux/init.h>

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#include <linux/kernel.h>

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#include <linux/module.h>

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#include <linux/skbuff.h>

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#include <linux/stringify.h>

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#include <net/dsfield.h>

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#include <net/dst.h>

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#include <net/inet_ecn.h>

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#include <net/ip6_route.h>

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#include <net/ipv6.h>

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#include <net/xfrm.h>

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static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)

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{

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	const struct ipv6hdr *outer_iph = ipv6_hdr(skb);

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	struct ipv6hdr *inner_iph = ipipv6_hdr(skb);

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	if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))

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		IP6_ECN_set_ce(inner_iph);

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}

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/* Add encapsulation header.

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 *

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 * The top IP header will be constructed per RFC 2401.

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 */

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static int xfrm6_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)

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{

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	struct dst_entry *dst = skb_dst(skb);

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	struct ipv6hdr *top_iph;

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	int dsfield;

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	skb_set_network_header(skb, -x->props.header_len);

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	skb->mac_header = skb->network_header +

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			  offsetof(struct ipv6hdr, nexthdr);

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	skb->transport_header = skb->network_header + sizeof(*top_iph);

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	top_iph = ipv6_hdr(skb);

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	top_iph->version = 6;

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	memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,

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	       sizeof(top_iph->flow_lbl));

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	top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);

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	dsfield = XFRM_MODE_SKB_CB(skb)->tos;

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	dsfield = INET_ECN_encapsulate(dsfield, dsfield);

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	if (x->props.flags & XFRM_STATE_NOECN)

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		dsfield &= ~INET_ECN_MASK;

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	ipv6_change_dsfield(top_iph, 0, dsfield);

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	top_iph->hop_limit = ip6_dst_hoplimit(dst->child);

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	ipv6_addr_copy(&top_iph->saddr, (const struct in6_addr *)&x->props.saddr);

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	ipv6_addr_copy(&top_iph->daddr, (const struct in6_addr *)&x->id.daddr);

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	return 0;

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}

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static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)

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{

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	int err = -EINVAL;

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	const unsigned char *old_mac;

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	if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPV6)

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		goto out;

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	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))

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		goto out;

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	if (skb_cloned(skb) &&

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	    (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))

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		goto out;

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	if (x->props.flags & XFRM_STATE_DECAP_DSCP)

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		ipv6_copy_dscp(ipv6_get_dsfield(ipv6_hdr(skb)),

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			       ipipv6_hdr(skb));

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	if (!(x->props.flags & XFRM_STATE_NOECN))

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		ipip6_ecn_decapsulate(skb);

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	old_mac = skb_mac_header(skb);

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	skb_set_mac_header(skb, -skb->mac_len);

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	memmove(skb_mac_header(skb), old_mac, skb->mac_len);

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	skb_reset_network_header(skb);

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	err = 0;

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out:

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	return err;

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}

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static struct xfrm_mode xfrm6_tunnel_mode = {

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	.input2 = xfrm6_mode_tunnel_input,

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	.input = xfrm_prepare_input,

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	.output2 = xfrm6_mode_tunnel_output,

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	.output = xfrm6_prepare_output,

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	.owner = THIS_MODULE,

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	.encap = XFRM_MODE_TUNNEL,

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	.flags = XFRM_MODE_FLAG_TUNNEL,

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};

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static int __init xfrm6_mode_tunnel_init(void)

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{

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	return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);

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}

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static void __exit xfrm6_mode_tunnel_exit(void)

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{

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	int err;

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	err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);

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	BUG_ON(err);

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}

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module_init(xfrm6_mode_tunnel_init);

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module_exit(xfrm6_mode_tunnel_exit);

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MODULE_LICENSE("GPL");

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MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);

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