[linux-block.git] / net / ipv6 / xfrm6_output.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * xfrm6_output.c - Common IPsec encapsulation code for IPv6.
 * Copyright (C) 2002 USAGI/WIDE Project
 * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
 */

#include <linux/if_ether.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/icmpv6.h>
#include <linux/netfilter_ipv6.h>
#include <net/dst.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/xfrm.h>

void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
{
	struct flowi6 fl6;
	struct sock *sk = skb->sk;

	fl6.flowi6_oif = sk->sk_bound_dev_if;
	fl6.daddr = ipv6_hdr(skb)->daddr;

	ipv6_local_rxpmtu(sk, &fl6, mtu);
}

void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
{
	struct flowi6 fl6;
	const struct ipv6hdr *hdr;
	struct sock *sk = skb->sk;

	hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
	fl6.fl6_dport = inet_sk(sk)->inet_dport;
	fl6.daddr = hdr->daddr;

	ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
}

static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	return xfrm_output(sk, skb);
}

static int xfrm6_noneed_fragment(struct sk_buff *skb)
{
	struct frag_hdr *fh;
	u8 prevhdr = ipv6_hdr(skb)->nexthdr;

	if (prevhdr != NEXTHDR_FRAGMENT)
		return 0;
	fh = (struct frag_hdr *)(skb->data + sizeof(struct ipv6hdr));
	if (fh->nexthdr == NEXTHDR_ESP || fh->nexthdr == NEXTHDR_AUTH)
		return 1;
	return 0;
}

static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	struct dst_entry *dst = skb_dst(skb);
	struct xfrm_state *x = dst->xfrm;
	unsigned int mtu;
	bool toobig;

#ifdef CONFIG_NETFILTER
	if (!x) {
		IP6CB(skb)->flags |= IP6SKB_REROUTED;
		return dst_output(net, sk, skb);
	}
#endif

	if (x->props.mode != XFRM_MODE_TUNNEL)
		goto skip_frag;

	if (skb->protocol == htons(ETH_P_IPV6))
		mtu = ip6_skb_dst_mtu(skb);
	else
		mtu = dst_mtu(skb_dst(skb));

	toobig = skb->len > mtu && !skb_is_gso(skb);

	if (toobig && xfrm6_local_dontfrag(skb->sk)) {
		xfrm6_local_rxpmtu(skb, mtu);
		kfree_skb(skb);
		return -EMSGSIZE;
	} else if (toobig && xfrm6_noneed_fragment(skb)) {
		skb->ignore_df = 1;
		goto skip_frag;
	} else if (!skb->ignore_df && toobig && skb->sk) {
		xfrm_local_error(skb, mtu);
		kfree_skb(skb);
		return -EMSGSIZE;
	}

	if (toobig || dst_allfrag(skb_dst(skb)))
		return ip6_fragment(net, sk, skb,
				    __xfrm6_output_finish);

skip_frag:
	return xfrm_output(sk, skb);
}

int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
			    net, sk, skb,  skb->dev, skb_dst(skb)->dev,
			    __xfrm6_output,
			    !(IP6CB(skb)->flags & IP6SKB_REROUTED));
}
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* xfrm6_output.c - Common IPsec encapsulation code for IPv6.
	4	* Copyright (C) 2002 USAGI/WIDE Project
	5	* Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
1da177e4 LT	6	*/
1da177e4 LT	7
406ef77c	8	#include <linux/if_ether.h>
36cf9acf HX	9	#include <linux/kernel.h>
36cf9acf HX	10	#include <linux/module.h>
1da177e4	11	#include <linux/skbuff.h>
1da177e4	12	#include <linux/icmpv6.h>
16a6677f	13	#include <linux/netfilter_ipv6.h>
36cf9acf	14	#include <net/dst.h>
1da177e4	15	#include <net/ipv6.h>
ad0081e4	16	#include <net/ip6_route.h>
1da177e4 LT	17	#include <net/xfrm.h>
1da177e4 LT	18
3e50ddd8	19	void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
dd767856 SK	20	{
	21	struct flowi6 fl6;
	22	struct sock *sk = skb->sk;
	23
	24	fl6.flowi6_oif = sk->sk_bound_dev_if;
4e3fd7a0	25	fl6.daddr = ipv6_hdr(skb)->daddr;
dd767856 SK	26
	27	ipv6_local_rxpmtu(sk, &fl6, mtu);
	28	}
	29
628e341f	30	void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
dd767856 SK	31	{
dd767856 SK	32	struct flowi6 fl6;
5d0ff542	33	const struct ipv6hdr *hdr;
dd767856 SK	34	struct sock *sk = skb->sk;
dd767856 SK	35
5d0ff542	36	hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
dd767856	37	fl6.fl6_dport = inet_sk(sk)->inet_dport;
5d0ff542	38	fl6.daddr = hdr->daddr;
dd767856 SK	39
	40	ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
	41	}
	42
7d8c6e39 EB	43	static int __xfrm6_output_finish(struct net net, struct sock sk, struct sk_buff *skb)
7d8c6e39 EB	44	{
2ab6096d	45	return xfrm_output(sk, skb);
7d8c6e39 EB	46	}
7d8c6e39 EB	47
4ff2980b LW	48	static int xfrm6_noneed_fragment(struct sk_buff *skb)
	49	{
	50	struct frag_hdr *fh;
	51	u8 prevhdr = ipv6_hdr(skb)->nexthdr;
	52
	53	if (prevhdr != NEXTHDR_FRAGMENT)
	54	return 0;
	55	fh = (struct frag_hdr *)(skb->data + sizeof(struct ipv6hdr));
	56	if (fh->nexthdr == NEXTHDR_ESP \|\| fh->nexthdr == NEXTHDR_AUTH)
	57	return 1;
	58	return 0;
	59	}
	60
0c4b51f0	61	static int __xfrm6_output(struct net net, struct sock sk, struct sk_buff *skb)
ad0081e4 DS	62	{
	63	struct dst_entry *dst = skb_dst(skb);
	64	struct xfrm_state *x = dst->xfrm;
40fc3054	65	unsigned int mtu;
93efac3f	66	bool toobig;
0ea9d5e3	67
5596732f SK	68	#ifdef CONFIG_NETFILTER
	69	if (!x) {
	70	IP6CB(skb)->flags \|= IP6SKB_REROUTED;
13206b6b	71	return dst_output(net, sk, skb);
5596732f SK	72	}
	73	#endif
	74
93efac3f HX	75	if (x->props.mode != XFRM_MODE_TUNNEL)
	76	goto skip_frag;
	77
5a25cf1e HFS	78	if (skb->protocol == htons(ETH_P_IPV6))
	79	mtu = ip6_skb_dst_mtu(skb);
	80	else
	81	mtu = dst_mtu(skb_dst(skb));
dd767856	82
93efac3f HX	83	toobig = skb->len > mtu && !skb_is_gso(skb);
93efac3f HX	84
ede64dd2	85	if (toobig && xfrm6_local_dontfrag(skb->sk)) {
dd767856	86	xfrm6_local_rxpmtu(skb, mtu);
215ab0f0	87	kfree_skb(skb);
dd767856	88	return -EMSGSIZE;
4ff2980b LW	89	} else if (toobig && xfrm6_noneed_fragment(skb)) {
	90	skb->ignore_df = 1;
	91	goto skip_frag;
93efac3f	92	} else if (!skb->ignore_df && toobig && skb->sk) {
628e341f	93	xfrm_local_error(skb, mtu);
215ab0f0	94	kfree_skb(skb);
dd767856 SK	95	return -EMSGSIZE;
dd767856 SK	96	}
ad0081e4	97
93efac3f	98	if (toobig \|\| dst_allfrag(skb_dst(skb)))
7d8c6e39 EB	99	return ip6_fragment(net, sk, skb,
7d8c6e39 EB	100	__xfrm6_output_finish);
93efac3f HX	101
93efac3f HX	102	skip_frag:
2ab6096d	103	return xfrm_output(sk, skb);
ad0081e4 DS	104	}
ad0081e4 DS	105
ede2059d	106	int xfrm6_output(struct net net, struct sock sk, struct sk_buff *skb)
16a6677f	107	{
29a26a56	108	return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
28f8bfd1	109	net, sk, skb, skb->dev, skb_dst(skb)->dev,
29a26a56	110	__xfrm6_output,
5596732f	111	!(IP6CB(skb)->flags & IP6SKB_REROUTED));
16a6677f	112	}