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linux-sg2042/net/ipv6/ipcomp6.c

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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 <linux/ipv6.h>
#include <linux/icmpv6.h>
struct ipcomp6_tfms {
struct list_head list;
struct crypto_tfm **tfms;
int users;
};
static DECLARE_MUTEX(ipcomp6_resource_sem);
static void **ipcomp6_scratches;
static int ipcomp6_scratch_users;
static LIST_HEAD(ipcomp6_tfms_list);
static int ipcomp6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
{
int err = 0;
u8 nexthdr = 0;
int hdr_len = skb->h.raw - skb->nh.raw;
unsigned char *tmp_hdr = NULL;
struct ipv6hdr *iph;
int plen, dlen;
struct ipcomp_data *ipcd = x->data;
u8 *start, *scratch;
struct crypto_tfm *tfm;
int cpu;
if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
skb_linearize(skb, GFP_ATOMIC) != 0) {
err = -ENOMEM;
goto out;
}
skb->ip_summed = CHECKSUM_NONE;
/* Remove ipcomp header and decompress original payload */
iph = skb->nh.ipv6h;
tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC);
if (!tmp_hdr)
goto out;
memcpy(tmp_hdr, iph, hdr_len);
nexthdr = *(u8 *)skb->data;
skb_pull(skb, sizeof(struct ipv6_comp_hdr));
skb->nh.raw += sizeof(struct ipv6_comp_hdr);
memcpy(skb->nh.raw, tmp_hdr, hdr_len);
iph = skb->nh.ipv6h;
iph->payload_len = htons(ntohs(iph->payload_len) - sizeof(struct ipv6_comp_hdr));
skb->h.raw = skb->data;
/* 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);
iph = skb->nh.ipv6h;
iph->payload_len = htons(skb->len);
out_put_cpu:
put_cpu();
out:
if (tmp_hdr)
kfree(tmp_hdr);
if (err)
goto error_out;
return nexthdr;
error_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_is_nonlinear(skb) || skb_cloned(skb)) &&
skb_linearize(skb, GFP_ATOMIC) != 0) {
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 = ntohl(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/"
"%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\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);
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:
xfrm_state_put(t);
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_cpu(i) {
void *scratch = *per_cpu_ptr(scratches, i);
if (scratch)
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_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_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_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);
down(&ipcomp6_resource_sem);
ipcomp6_free_data(ipcd);
up(&ipcomp6_resource_sem);
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 = kmalloc(sizeof(*ipcd), GFP_KERNEL);
if (!ipcd)
goto out;
memset(ipcd, 0, sizeof(*ipcd));
x->props.header_len = 0;
if (x->props.mode)
x->props.header_len += sizeof(struct ipv6hdr);
down(&ipcomp6_resource_sem);
if (!ipcomp6_alloc_scratches())
goto error;
ipcd->tfms = ipcomp6_alloc_tfms(x->calg->alg_name);
if (!ipcd->tfms)
goto error;
up(&ipcomp6_resource_sem);
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:
down(&ipcomp6_resource_sem);
error:
ipcomp6_free_data(ipcd);
up(&ipcomp6_resource_sem);
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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