[linux.git] / net / ipv4 / xfrm4_output.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * xfrm4_output.c - Common IPsec encapsulation code for IPv4.
 * Copyright (c) 2004 Herbert Xu <[email protected]>
 */

#include <linux/if_ether.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netfilter_ipv4.h>
#include <net/dst.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/icmp.h>

static int xfrm4_tunnel_check_size(struct sk_buff *skb)
{
	int mtu, ret = 0;

	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
		goto out;

	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
		goto out;

	mtu = dst_mtu(skb_dst(skb));
	if ((!skb_is_gso(skb) && skb->len > mtu) ||
	    (skb_is_gso(skb) &&
	     !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
		skb->protocol = htons(ETH_P_IP);

		if (skb->sk)
			xfrm_local_error(skb, mtu);
		else
			icmp_send(skb, ICMP_DEST_UNREACH,
				  ICMP_FRAG_NEEDED, htonl(mtu));
		ret = -EMSGSIZE;
	}
out:
	return ret;
}

int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;

	err = xfrm4_tunnel_check_size(skb);
	if (err)
		return err;

	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;

	return xfrm4_extract_header(skb);
}

int xfrm4_output_finish(struct sock *sk, struct sk_buff *skb)
{
	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));

#ifdef CONFIG_NETFILTER
	IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
#endif

	return xfrm_output(sk, skb);
}

static int __xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	struct xfrm_state *x = skb_dst(skb)->xfrm;
	const struct xfrm_state_afinfo *afinfo;
	int ret = -EAFNOSUPPORT;

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

	rcu_read_lock();
	afinfo = xfrm_state_afinfo_get_rcu(x->outer_mode.family);
	if (likely(afinfo))
		ret = afinfo->output_finish(sk, skb);
	else
		kfree_skb(skb);
	rcu_read_unlock();

	return ret;
}

int xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
			    net, sk, skb, NULL, skb_dst(skb)->dev,
			    __xfrm4_output,
			    !(IPCB(skb)->flags & IPSKB_REROUTED));
}

void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
{
	struct iphdr *hdr;

	hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
	ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
		       inet_sk(skb->sk)->inet_dport, mtu);
}
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* xfrm4_output.c - Common IPsec encapsulation code for IPv4.
	4	* Copyright (c) 2004 Herbert Xu <[email protected]>
1da177e4 LT	5	*/
1da177e4 LT	6
09b8f7a9 HX	7	#include <linux/if_ether.h>
09b8f7a9 HX	8	#include <linux/kernel.h>
36cf9acf	9	#include <linux/module.h>
1da177e4	10	#include <linux/skbuff.h>
16a6677f	11	#include <linux/netfilter_ipv4.h>
36cf9acf	12	#include <net/dst.h>
1da177e4 LT	13	#include <net/ip.h>
	14	#include <net/xfrm.h>
	15	#include <net/icmp.h>
	16
1da177e4 LT	17	static int xfrm4_tunnel_check_size(struct sk_buff *skb)
	18	{
	19	int mtu, ret = 0;
1da177e4 LT	20
	21	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
	22	goto out;
	23
60ff7467	24	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) \|\| skb->ignore_df)
1da177e4 LT	25	goto out;
1da177e4 LT	26
5a25cf1e	27	mtu = dst_mtu(skb_dst(skb));
d77e38e6	28	if ((!skb_is_gso(skb) && skb->len > mtu) \|\|
80f5974d DA	29	(skb_is_gso(skb) &&
80f5974d DA	30	!skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
ca064bd8 SK	31	skb->protocol = htons(ETH_P_IP);
ca064bd8 SK	32
b00897b8	33	if (skb->sk)
628e341f	34	xfrm_local_error(skb, mtu);
b00897b8 SK	35	else
	36	icmp_send(skb, ICMP_DEST_UNREACH,
	37	ICMP_FRAG_NEEDED, htonl(mtu));
1da177e4 LT	38	ret = -EMSGSIZE;
	39	}
	40	out:
	41	return ret;
	42	}
	43
36cf9acf HX	44	int xfrm4_extract_output(struct xfrm_state x, struct sk_buff skb)
	45	{
	46	int err;
	47
	48	err = xfrm4_tunnel_check_size(skb);
	49	if (err)
	50	return err;
	51
60d5fcfb HX	52	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
60d5fcfb HX	53
36cf9acf HX	54	return xfrm4_extract_header(skb);
	55	}
	56
7026b1dd	57	int xfrm4_output_finish(struct sock sk, struct sk_buff skb)
09b8f7a9	58	{
5596732f	59	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
5596732f SK	60
	61	#ifdef CONFIG_NETFILTER
	62	IPCB(skb)->flags \|= IPSKB_XFRM_TRANSFORMED;
	63	#endif
	64
7026b1dd	65	return xfrm_output(sk, skb);
5596732f SK	66	}
5596732f SK	67
0c4b51f0	68	static int __xfrm4_output(struct net net, struct sock sk, struct sk_buff *skb)
5596732f SK	69	{
5596732f SK	70	struct xfrm_state *x = skb_dst(skb)->xfrm;
733a5fac FW	71	const struct xfrm_state_afinfo *afinfo;
733a5fac FW	72	int ret = -EAFNOSUPPORT;
5596732f	73
09b8f7a9	74	#ifdef CONFIG_NETFILTER
5596732f	75	if (!x) {
09b8f7a9	76	IPCB(skb)->flags \|= IPSKB_REROUTED;
13206b6b	77	return dst_output(net, sk, skb);
09b8f7a9	78	}
862b82c6	79	#endif
09b8f7a9	80
733a5fac	81	rcu_read_lock();
c9500d7b	82	afinfo = xfrm_state_afinfo_get_rcu(x->outer_mode.family);
733a5fac FW	83	if (likely(afinfo))
	84	ret = afinfo->output_finish(sk, skb);
	85	else
	86	kfree_skb(skb);
	87	rcu_read_unlock();
	88
	89	return ret;
09b8f7a9 HX	90	}
09b8f7a9 HX	91
ede2059d	92	int xfrm4_output(struct net net, struct sock sk, struct sk_buff *skb)
16a6677f	93	{
29a26a56 EB	94	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
	95	net, sk, skb, NULL, skb_dst(skb)->dev,
	96	__xfrm4_output,
48d5cad8	97	!(IPCB(skb)->flags & IPSKB_REROUTED));
16a6677f	98	}
628e341f HFS	99
	100	void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
	101	{
	102	struct iphdr *hdr;
	103
	104	hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
	105	ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
	106	inet_sk(skb->sk)->inet_dport, mtu);
	107	}