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kernel-ark/net/ipv6/ipcomp6.c
Herbert Xu 364c6badde [NET]: Clean up skb_linearize 
The linearisation operation doesn't need to be super-optimised.  So we can
replace __skb_linearize with __pskb_pull_tail which does the same thing but
is more general.

Also, most users of skb_linearize end up testing whether the skb is linear
or not so it helps to make skb_linearize do just that.

Some callers of skb_linearize also use it to copy cloned data, so it's
useful to have a new function skb_linearize_cow to copy the data if it's
either non-linear or cloned.

Last but not least, I've removed the gfp argument since nobody uses it
anymore.  If it's ever needed we can easily add it back.

Misc bugs fixed by this patch:

* via-velocity error handling (also, no SG => no frags)

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:30:16 -07:00

501 lines
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/*
* 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/config.h>
#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_tfm **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_tfm *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_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_tfm *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, __u32 info)
{
u32 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;
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;
t->props.mode = 1;
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;
u32 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_tfm **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_tfm *tfm = *per_cpu_ptr(tfms, cpu);
crypto_free_tfm(tfm);
}
free_percpu(tfms);
}
static struct crypto_tfm **ipcomp6_alloc_tfms(const char *alg_name)
{
struct ipcomp6_tfms *pos;
struct crypto_tfm **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_tfm *tfm;
tfms = pos->tfms;
tfm = *per_cpu_ptr(tfms, cpu);
if (!strcmp(crypto_tfm_alg_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_tfm *);
if (!tfms)
goto error;
for_each_possible_cpu(cpu) {
struct crypto_tfm *tfm = crypto_alloc_tfm(alg_name, 0);
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)
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) {
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,
};
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);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
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