[net-next-2.6.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/if_ether.h>
#include <linux/kernel.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;

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

	IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;

	if (!(ip_hdr(skb)->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_PARTIAL) {
		err = skb_checksum_help(skb);
		if (err)
			goto error_nolock;
	}

	if (x->props.mode == XFRM_MODE_TUNNEL) {
		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(x, 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 != XFRM_MODE_TUNNEL));

	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_finish2(struct sk_buff *skb)
{
	int err;

	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_finish2);
		if (unlikely(err != 1))
			break;
	}

	return err;
}

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

#ifdef CONFIG_NETFILTER
	if (!skb->dst->xfrm) {
		IPCB(skb)->flags |= IPSKB_REROUTED;
		return dst_output(skb);
	}
#endif

	if (!skb_is_gso(skb))
		return xfrm4_output_finish2(skb);

	skb->protocol = htons(ETH_P_IP);
	segs = skb_gso_segment(skb, 0);
	kfree_skb(skb);
	if (unlikely(IS_ERR(segs)))
		return PTR_ERR(segs);

	do {
		struct sk_buff *nskb = segs->next;
		int err;

		segs->next = NULL;
		err = xfrm4_output_finish2(segs);

		if (unlikely(err)) {
			while ((segs = nskb)) {
				nskb = segs->next;
				segs->next = NULL;
				kfree_skb(segs);
			}
			return err;
		}

		segs = nskb;
	} while (segs);

	return 0;
}

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>
e905a9ed	4	*
1da177e4 LT	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>
09b8f7a9 HX	12	#include <linux/if_ether.h>
09b8f7a9 HX	13	#include <linux/kernel.h>
1da177e4 LT	14	#include <linux/skbuff.h>
1da177e4 LT	15	#include <linux/spinlock.h>
16a6677f	16	#include <linux/netfilter_ipv4.h>
1da177e4 LT	17	#include <net/ip.h>
	18	#include <net/xfrm.h>
	19	#include <net/icmp.h>
	20
1da177e4 LT	21	static int xfrm4_tunnel_check_size(struct sk_buff *skb)
	22	{
	23	int mtu, ret = 0;
	24	struct dst_entry *dst;
1da177e4 LT	25
	26	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
	27	goto out;
	28
	29	IPCB(skb)->flags \|= IPSKB_XFRM_TUNNEL_SIZE;
e905a9ed	30
eddc9ec5	31	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) \|\| skb->local_df)
1da177e4 LT	32	goto out;
	33
	34	dst = skb->dst;
	35	mtu = dst_mtu(dst);
	36	if (skb->len > mtu) {
	37	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
	38	ret = -EMSGSIZE;
	39	}
	40	out:
	41	return ret;
	42	}
	43
16a6677f	44	static int xfrm4_output_one(struct sk_buff *skb)
1da177e4 LT	45	{
	46	struct dst_entry *dst = skb->dst;
	47	struct xfrm_state *x = dst->xfrm;
	48	int err;
e905a9ed	49
84fa7933 PM	50	if (skb->ip_summed == CHECKSUM_PARTIAL) {
84fa7933 PM	51	err = skb_checksum_help(skb);
1da177e4 LT	52	if (err)
	53	goto error_nolock;
	54	}
	55
7e49e6de	56	if (x->props.mode == XFRM_MODE_TUNNEL) {
1da177e4 LT	57	err = xfrm4_tunnel_check_size(skb);
	58	if (err)
	59	goto error_nolock;
	60	}
	61
16a6677f PM	62	do {
	63	spin_lock_bh(&x->lock);
	64	err = xfrm_state_check(x, skb);
	65	if (err)
	66	goto error;
1da177e4	67
eb878e84	68	err = x->mode->output(x, skb);
b59f45d0 HX	69	if (err)
b59f45d0 HX	70	goto error;
1da177e4	71
16a6677f PM	72	err = x->type->output(x, skb);
	73	if (err)
	74	goto error;
1da177e4	75
16a6677f PM	76	x->curlft.bytes += skb->len;
16a6677f PM	77	x->curlft.packets++;
1da177e4	78
16a6677f	79	spin_unlock_bh(&x->lock);
e905a9ed	80
16a6677f PM	81	if (!(skb->dst = dst_pop(dst))) {
	82	err = -EHOSTUNREACH;
	83	goto error_nolock;
	84	}
	85	dst = skb->dst;
	86	x = dst->xfrm;
7e49e6de	87	} while (x && (x->props.mode != XFRM_MODE_TUNNEL));
16a6677f	88
3e3850e9	89	IPCB(skb)->flags \|= IPSKB_XFRM_TRANSFORMED;
16a6677f	90	err = 0;
1da177e4 LT	91
	92	out_exit:
	93	return err;
	94	error:
	95	spin_unlock_bh(&x->lock);
	96	error_nolock:
	97	kfree_skb(skb);
	98	goto out_exit;
	99	}
16a6677f	100
09b8f7a9	101	static int xfrm4_output_finish2(struct sk_buff *skb)
16a6677f PM	102	{
	103	int err;
	104
	105	while (likely((err = xfrm4_output_one(skb)) == 0)) {
	106	nf_reset(skb);
	107
	108	err = nf_hook(PF_INET, NF_IP_LOCAL_OUT, &skb, NULL,
	109	skb->dst->dev, dst_output);
	110	if (unlikely(err != 1))
	111	break;
	112
	113	if (!skb->dst->xfrm)
	114	return dst_output(skb);
	115
	116	err = nf_hook(PF_INET, NF_IP_POST_ROUTING, &skb, NULL,
09b8f7a9	117	skb->dst->dev, xfrm4_output_finish2);
16a6677f PM	118	if (unlikely(err != 1))
	119	break;
	120	}
	121
	122	return err;
	123	}
	124
09b8f7a9 HX	125	static int xfrm4_output_finish(struct sk_buff *skb)
	126	{
	127	struct sk_buff *segs;
	128
	129	#ifdef CONFIG_NETFILTER
	130	if (!skb->dst->xfrm) {
	131	IPCB(skb)->flags \|= IPSKB_REROUTED;
	132	return dst_output(skb);
	133	}
	134	#endif
	135
89114afd	136	if (!skb_is_gso(skb))
09b8f7a9 HX	137	return xfrm4_output_finish2(skb);
	138
	139	skb->protocol = htons(ETH_P_IP);
	140	segs = skb_gso_segment(skb, 0);
	141	kfree_skb(skb);
	142	if (unlikely(IS_ERR(segs)))
	143	return PTR_ERR(segs);
	144
	145	do {
	146	struct sk_buff *nskb = segs->next;
	147	int err;
	148
	149	segs->next = NULL;
	150	err = xfrm4_output_finish2(segs);
	151
	152	if (unlikely(err)) {
	153	while ((segs = nskb)) {
	154	nskb = segs->next;
	155	segs->next = NULL;
	156	kfree_skb(segs);
	157	}
	158	return err;
	159	}
	160
	161	segs = nskb;
	162	} while (segs);
	163
	164	return 0;
	165	}
	166
16a6677f PM	167	int xfrm4_output(struct sk_buff *skb)
16a6677f PM	168	{
48d5cad8 PM	169	return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dst->dev,
	170	xfrm4_output_finish,
	171	!(IPCB(skb)->flags & IPSKB_REROUTED));
16a6677f	172	}