/* * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173 * * Copyright (C)2003 USAGI/WIDE Project * * Author	Mitsuru KANDA  <mk@linux-ipv6.org> * * 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. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA *//* * [Memo] * * Outbound: *  The compression of IP datagram MUST be done before AH/ESP processing, *  fragmentation, and the addition of Hop-by-Hop/Routing header. * * Inbound: *  The decompression of IP datagram MUST be done after the reassembly, *  AH/ESP processing. */#include <linux/module.h>#include <net/ip.h>#include <net/xfrm.h>#include <net/ipcomp.h>#include <asm/scatterlist.h>#include <asm/semaphore.h>#include <linux/crypto.h>#include <linux/pfkeyv2.h>#include <linux/random.h>#include <linux/percpu.h>#include <linux/smp.h>#include <linux/list.h>#include <linux/vmalloc.h>#include <linux/rtnetlink.h>#include <net/icmp.h>#include <net/ipv6.h>#include <net/protocol.h>#include <linux/ipv6.h>#include <linux/icmpv6.h>#include <linux/mutex.h> struct ipcomp6_tfms {	struct list_head list;	struct crypto_comp **tfms;	int users;}; static DEFINE_MUTEX(ipcomp6_resource_mutex);static void **ipcomp6_scratches;static int ipcomp6_scratch_users;static LIST_HEAD(ipcomp6_tfms_list); static int ipcomp6_input(struct xfrm_state *x, struct sk_buff *skb){	int err = -ENOMEM;	struct ipv6hdr *iph;	struct ipv6_comp_hdr *ipch;	int plen, dlen;	struct ipcomp_data *ipcd = x->data;	u8 *start, *scratch;	struct crypto_comp *tfm;	int cpu; 	if (skb_linearize_cow(skb))		goto out; 	skb->ip_summed = CHECKSUM_NONE; 	/* Remove ipcomp header and decompress original payload */	iph = skb->nh.ipv6h;	ipch = (void *)skb->data;	skb->h.raw = skb->nh.raw + sizeof(*ipch);	__skb_pull(skb, sizeof(*ipch)); 	/* decompression */	plen = skb->len;	dlen = IPCOMP_SCRATCH_SIZE;	start = skb->data; 	cpu = get_cpu();	scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);	tfm = *per_cpu_ptr(ipcd->tfms, cpu); 	err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);	if (err) {		err = -EINVAL;		goto out_put_cpu;	} 	if (dlen < (plen + sizeof(struct ipv6_comp_hdr))) {		err = -EINVAL;		goto out_put_cpu;	} 	err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);	if (err) {		goto out_put_cpu;	} 	skb->truesize += dlen - plen;	__skb_put(skb, dlen - plen);	memcpy(skb->data, scratch, dlen);	err = ipch->nexthdr; out_put_cpu:	put_cpu();out:	return err;} static int ipcomp6_output(struct xfrm_state *x, struct sk_buff *skb){	int err;	struct ipv6hdr *top_iph;	int hdr_len;	struct ipv6_comp_hdr *ipch;	struct ipcomp_data *ipcd = x->data;	int plen, dlen;	u8 *start, *scratch;	struct crypto_comp *tfm;	int cpu; 	hdr_len = skb->h.raw - skb->data; 	/* check whether datagram len is larger than threshold */	if ((skb->len - hdr_len) < ipcd->threshold) {		goto out_ok;	} 	if (skb_linearize_cow(skb))		goto out_ok; 	/* compression */	plen = skb->len - hdr_len;	dlen = IPCOMP_SCRATCH_SIZE;	start = skb->h.raw; 	cpu = get_cpu();	scratch = *per_cpu_ptr(ipcomp6_scratches, cpu);	tfm = *per_cpu_ptr(ipcd->tfms, cpu); 	err = crypto_comp_compress(tfm, start, plen, scratch, &dlen);	if (err || (dlen + sizeof(struct ipv6_comp_hdr)) >= plen) {		put_cpu();		goto out_ok;	}	memcpy(start + sizeof(struct ip_comp_hdr), scratch, dlen);	put_cpu();	pskb_trim(skb, hdr_len + dlen + sizeof(struct ip_comp_hdr)); 	/* insert ipcomp header and replace datagram */	top_iph = (struct ipv6hdr *)skb->data; 	top_iph->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); 	ipch = (struct ipv6_comp_hdr *)start;	ipch->nexthdr = *skb->nh.raw;	ipch->flags = 0;	ipch->cpi = htons((u16 )ntohl(x->id.spi));	*skb->nh.raw = IPPROTO_COMP; out_ok:	return 0;} static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,				int type, int code, int offset, __be32 info){	__be32 spi;	struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;	struct ipv6_comp_hdr *ipcomph = (struct ipv6_comp_hdr*)(skb->data+offset);	struct xfrm_state *x; 	if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)		return; 	spi = htonl(ntohs(ipcomph->cpi));	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);	if (!x)		return; 	printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/" NIP6_FMT "\n",			spi, NIP6(iph->daddr));	xfrm_state_put(x);} static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x){	struct xfrm_state *t = NULL;	u8 mode = XFRM_MODE_TUNNEL; 	t = xfrm_state_alloc();	if (!t)		goto out; 	t->id.proto = IPPROTO_IPV6;	t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);	if (!t->id.spi)		goto error; 	memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));	memcpy(&t->sel, &x->sel, sizeof(t->sel));	t->props.family = AF_INET6;	if (x->props.mode == XFRM_MODE_BEET)		mode = x->props.mode;	t->props.mode = mode;	memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr)); 	if (xfrm_init_state(t))		goto error; 	atomic_set(&t->tunnel_users, 1); out:	return t; error:	t->km.state = XFRM_STATE_DEAD;	xfrm_state_put(t);	t = NULL;	goto out;} static int ipcomp6_tunnel_attach(struct xfrm_state *x){	int err = 0;	struct xfrm_state *t = NULL;	__be32 spi; 	spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);	if (spi)		t = xfrm_state_lookup((xfrm_address_t *)&x->id.daddr,					      spi, IPPROTO_IPV6, AF_INET6);	if (!t) {		t = ipcomp6_tunnel_create(x);		if (!t) {			err = -EINVAL;			goto out;		}		xfrm_state_insert(t);		xfrm_state_hold(t);	}	x->tunnel = t;	atomic_inc(&t->tunnel_users); out:	return err;} static void ipcomp6_free_scratches(void){	int i;	void **scratches; 	if (--ipcomp6_scratch_users)		return; 	scratches = ipcomp6_scratches;	if (!scratches)		return; 	for_each_possible_cpu(i) {		void *scratch = *per_cpu_ptr(scratches, i); 		vfree(scratch);	} 	free_percpu(scratches);} static void **ipcomp6_alloc_scratches(void){	int i;	void **scratches; 	if (ipcomp6_scratch_users++)		return ipcomp6_scratches; 	scratches = alloc_percpu(void *);	if (!scratches)		return NULL; 	ipcomp6_scratches = scratches; 	for_each_possible_cpu(i) {		void *scratch = vmalloc(IPCOMP_SCRATCH_SIZE);		if (!scratch)			return NULL;		*per_cpu_ptr(scratches, i) = scratch;	} 	return scratches;} static void ipcomp6_free_tfms(struct crypto_comp **tfms){	struct ipcomp6_tfms *pos;	int cpu; 	list_for_each_entry(pos, &ipcomp6_tfms_list, list) {		if (pos->tfms == tfms)			break;	} 	BUG_TRAP(pos); 	if (--pos->users)		return; 	list_del(&pos->list);	kfree(pos); 	if (!tfms)		return; 	for_each_possible_cpu(cpu) {		struct crypto_comp *tfm = *per_cpu_ptr(tfms, cpu);		crypto_free_comp(tfm);	}	free_percpu(tfms);} static struct crypto_comp **ipcomp6_alloc_tfms(const char *alg_name){	struct ipcomp6_tfms *pos;	struct crypto_comp **tfms;	int cpu; 	/* This can be any valid CPU ID so we don't need locking. */	cpu = raw_smp_processor_id(); 	list_for_each_entry(pos, &ipcomp6_tfms_list, list) {		struct crypto_comp *tfm; 		tfms = pos->tfms;		tfm = *per_cpu_ptr(tfms, cpu); 		if (!strcmp(crypto_comp_name(tfm), alg_name)) {			pos->users++;			return tfms;		}	} 	pos = kmalloc(sizeof(*pos), GFP_KERNEL);	if (!pos)		return NULL; 	pos->users = 1;	INIT_LIST_HEAD(&pos->list);	list_add(&pos->list, &ipcomp6_tfms_list); 	pos->tfms = tfms = alloc_percpu(struct crypto_comp *);	if (!tfms)		goto error; 	for_each_possible_cpu(cpu) {		struct crypto_comp *tfm = crypto_alloc_comp(alg_name, 0,							    CRYPTO_ALG_ASYNC);		if (!tfm)			goto error;		*per_cpu_ptr(tfms, cpu) = tfm;	} 	return tfms; error:	ipcomp6_free_tfms(tfms);	return NULL;} static void ipcomp6_free_data(struct ipcomp_data *ipcd){	if (ipcd->tfms)		ipcomp6_free_tfms(ipcd->tfms);	ipcomp6_free_scratches();} static void ipcomp6_destroy(struct xfrm_state *x){	struct ipcomp_data *ipcd = x->data;	if (!ipcd)		return;	xfrm_state_delete_tunnel(x);	mutex_lock(&ipcomp6_resource_mutex);	ipcomp6_free_data(ipcd);	mutex_unlock(&ipcomp6_resource_mutex);	kfree(ipcd); 	xfrm6_tunnel_free_spi((xfrm_address_t *)&x->props.saddr);} static int ipcomp6_init_state(struct xfrm_state *x){	int err;	struct ipcomp_data *ipcd;	struct xfrm_algo_desc *calg_desc; 	err = -EINVAL;	if (!x->calg)		goto out; 	if (x->encap)		goto out; 	err = -ENOMEM;	ipcd = kzalloc(sizeof(*ipcd), GFP_KERNEL);	if (!ipcd)		goto out; 	x->props.header_len = 0;	if (x->props.mode == XFRM_MODE_TUNNEL)		x->props.header_len += sizeof(struct ipv6hdr); 	mutex_lock(&ipcomp6_resource_mutex);	if (!ipcomp6_alloc_scratches())		goto error; 	ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);	if (!ipcd->tfms)		goto error;	mutex_unlock(&ipcomp6_resource_mutex); 	if (x->props.mode == XFRM_MODE_TUNNEL) {		err = ipcomp6_tunnel_attach(x);		if (err)			goto error_tunnel;	} 	calg_desc = xfrm_calg_get_byname(x->calg->alg_name, 0);	BUG_ON(!calg_desc);	ipcd->threshold = calg_desc->uinfo.comp.threshold;	x->data = ipcd;	err = 0;out:	return err;error_tunnel:	mutex_lock(&ipcomp6_resource_mutex);error:	ipcomp6_free_data(ipcd);	mutex_unlock(&ipcomp6_resource_mutex);	kfree(ipcd); 	goto out;} static struct xfrm_type ipcomp6_type ={	.description	= "IPCOMP6",	.owner		= THIS_MODULE,	.proto		= IPPROTO_COMP,	.init_state	= ipcomp6_init_state,	.destructor	= ipcomp6_destroy,	.input		= ipcomp6_input,	.output		= ipcomp6_output,	.hdr_offset	= xfrm6_find_1stfragopt,}; static struct inet6_protocol ipcomp6_protocol ={	.handler	= xfrm6_rcv,	.err_handler	= ipcomp6_err,	.flags		= INET6_PROTO_NOPOLICY,}; static int __init ipcomp6_init(void){	if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {		printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");		return -EAGAIN;	}	if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {		printk(KERN_INFO "ipcomp6 init: can't add protocol\n");		xfrm_unregister_type(&ipcomp6_type, AF_INET6);		return -EAGAIN;	}	return 0;} static void __exit ipcomp6_fini(void){	if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)		printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");	if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)		printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");} module_init(ipcomp6_init);module_exit(ipcomp6_fini);

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