[mirror_ubuntu-focal-kernel.git] / net / ipv4 / xfrm4_output.c

/*
 * xfrm4_output.c - Common IPsec encapsulation code for IPv4.
 * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
 * 
 * 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.
 */

#include <linux/compiler.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/netfilter_ipv4.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;
	struct dst_entry *dst;
	struct iphdr *iph = skb->nh.iph;

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

	IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
	
	if (!(iph->frag_off & htons(IP_DF)) || skb->local_df)
		goto out;

	dst = skb->dst;
	mtu = dst_mtu(dst);
	if (skb->len > mtu) {
		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
		ret = -EMSGSIZE;
	}
out:
	return ret;
}

static int xfrm4_output_one(struct sk_buff *skb)
{
	struct dst_entry *dst = skb->dst;
	struct xfrm_state *x = dst->xfrm;
	int err;
	
	if (skb->ip_summed == CHECKSUM_HW) {
		err = skb_checksum_help(skb, 0);
		if (err)
			goto error_nolock;
	}

	if (x->props.mode) {
		err = xfrm4_tunnel_check_size(skb);
		if (err)
			goto error_nolock;
	}

	do {
		spin_lock_bh(&x->lock);
		err = xfrm_state_check(x, skb);
		if (err)
			goto error;

		err = x->mode->output(skb);
		if (err)
			goto error;

		err = x->type->output(x, skb);
		if (err)
			goto error;

		x->curlft.bytes += skb->len;
		x->curlft.packets++;

		spin_unlock_bh(&x->lock);
	
		if (!(skb->dst = dst_pop(dst))) {
			err = -EHOSTUNREACH;
			goto error_nolock;
		}
		dst = skb->dst;
		x = dst->xfrm;
	} while (x && !x->props.mode);

	IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
	err = 0;

out_exit:
	return err;
error:
	spin_unlock_bh(&x->lock);
error_nolock:
	kfree_skb(skb);
	goto out_exit;
}

static int xfrm4_output_finish(struct sk_buff *skb)
{
	int err;

#ifdef CONFIG_NETFILTER
	if (!skb->dst->xfrm) {
		IPCB(skb)->flags |= IPSKB_REROUTED;
		return dst_output(skb);
	}
#endif
	while (likely((err = xfrm4_output_one(skb)) == 0)) {
		nf_reset(skb);

		err = nf_hook(PF_INET, NF_IP_LOCAL_OUT, &skb, NULL,
			      skb->dst->dev, dst_output);
		if (unlikely(err != 1))
			break;

		if (!skb->dst->xfrm)
			return dst_output(skb);

		err = nf_hook(PF_INET, NF_IP_POST_ROUTING, &skb, NULL,
			      skb->dst->dev, xfrm4_output_finish);
		if (unlikely(err != 1))
			break;
	}

	return err;
}

int xfrm4_output(struct sk_buff *skb)
{
	return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dst->dev,
			    xfrm4_output_finish,
			    !(IPCB(skb)->flags & IPSKB_REROUTED));
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* xfrm4_output.c - Common IPsec encapsulation code for IPv4.
	3	* Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License
	7	* as published by the Free Software Foundation; either version
	8	* 2 of the License, or (at your option) any later version.
	9	*/
	10
16a6677f	11	#include <linux/compiler.h>
1da177e4 LT	12	#include <linux/skbuff.h>
1da177e4 LT	13	#include <linux/spinlock.h>
16a6677f	14	#include <linux/netfilter_ipv4.h>
1da177e4 LT	15	#include <net/ip.h>
	16	#include <net/xfrm.h>
	17	#include <net/icmp.h>
	18
1da177e4 LT	19	static int xfrm4_tunnel_check_size(struct sk_buff *skb)
	20	{
	21	int mtu, ret = 0;
	22	struct dst_entry *dst;
	23	struct iphdr *iph = skb->nh.iph;
	24
	25	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
	26	goto out;
	27
	28	IPCB(skb)->flags \|= IPSKB_XFRM_TUNNEL_SIZE;
	29
	30	if (!(iph->frag_off & htons(IP_DF)) \|\| skb->local_df)
	31	goto out;
	32
	33	dst = skb->dst;
	34	mtu = dst_mtu(dst);
	35	if (skb->len > mtu) {
	36	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
	37	ret = -EMSGSIZE;
	38	}
	39	out:
	40	return ret;
	41	}
	42
16a6677f	43	static int xfrm4_output_one(struct sk_buff *skb)
1da177e4 LT	44	{
	45	struct dst_entry *dst = skb->dst;
	46	struct xfrm_state *x = dst->xfrm;
	47	int err;
	48
	49	if (skb->ip_summed == CHECKSUM_HW) {
	50	err = skb_checksum_help(skb, 0);
	51	if (err)
	52	goto error_nolock;
	53	}
	54
	55	if (x->props.mode) {
	56	err = xfrm4_tunnel_check_size(skb);
	57	if (err)
	58	goto error_nolock;
	59	}
	60
16a6677f PM	61	do {
	62	spin_lock_bh(&x->lock);
	63	err = xfrm_state_check(x, skb);
	64	if (err)
	65	goto error;
1da177e4	66
b59f45d0 HX	67	err = x->mode->output(skb);
	68	if (err)
	69	goto error;
1da177e4	70
16a6677f PM	71	err = x->type->output(x, skb);
	72	if (err)
	73	goto error;
1da177e4	74
16a6677f PM	75	x->curlft.bytes += skb->len;
16a6677f PM	76	x->curlft.packets++;
1da177e4	77
16a6677f	78	spin_unlock_bh(&x->lock);
1da177e4	79
16a6677f PM	80	if (!(skb->dst = dst_pop(dst))) {
	81	err = -EHOSTUNREACH;
	82	goto error_nolock;
	83	}
	84	dst = skb->dst;
	85	x = dst->xfrm;
	86	} while (x && !x->props.mode);
	87
3e3850e9	88	IPCB(skb)->flags \|= IPSKB_XFRM_TRANSFORMED;
16a6677f	89	err = 0;
1da177e4 LT	90
	91	out_exit:
	92	return err;
	93	error:
	94	spin_unlock_bh(&x->lock);
	95	error_nolock:
	96	kfree_skb(skb);
	97	goto out_exit;
	98	}
16a6677f	99
48d5cad8	100	static int xfrm4_output_finish(struct sk_buff *skb)
16a6677f PM	101	{
	102	int err;
	103
48d5cad8 PM	104	#ifdef CONFIG_NETFILTER
	105	if (!skb->dst->xfrm) {
	106	IPCB(skb)->flags \|= IPSKB_REROUTED;
	107	return dst_output(skb);
	108	}
	109	#endif
16a6677f PM	110	while (likely((err = xfrm4_output_one(skb)) == 0)) {
	111	nf_reset(skb);
	112
	113	err = nf_hook(PF_INET, NF_IP_LOCAL_OUT, &skb, NULL,
	114	skb->dst->dev, dst_output);
	115	if (unlikely(err != 1))
	116	break;
	117
	118	if (!skb->dst->xfrm)
	119	return dst_output(skb);
	120
	121	err = nf_hook(PF_INET, NF_IP_POST_ROUTING, &skb, NULL,
	122	skb->dst->dev, xfrm4_output_finish);
	123	if (unlikely(err != 1))
	124	break;
	125	}
	126
	127	return err;
	128	}
	129
	130	int xfrm4_output(struct sk_buff *skb)
	131	{
48d5cad8 PM	132	return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dst->dev,
	133	xfrm4_output_finish,
	134	!(IPCB(skb)->flags & IPSKB_REROUTED));
16a6677f	135	}