Commit af4f80fe authored by James Morris's avatar James Morris Committed by David S. Miller

[IPSEC]: Add initial IPCOMP support.

parent de2d745b
......@@ -362,5 +362,13 @@ config INET_ESP
If unsure, say Y.
config INET_IPCOMP
tristate "IP: IPComp transformation"
---help---
Support for IP Paylod Compression (RFC3173), typically needed
for IPsec.
If unsure, say Y.
source "net/ipv4/netfilter/Kconfig"
......@@ -18,6 +18,7 @@ obj-$(CONFIG_NET_IPGRE) += ip_gre.o
obj-$(CONFIG_SYN_COOKIES) += syncookies.o
obj-$(CONFIG_INET_AH) += ah.o
obj-$(CONFIG_INET_ESP) += esp.o
obj-$(CONFIG_INET_IPCOMP) += ipcomp.o
obj-$(CONFIG_IP_PNP) += ipconfig.o
obj-$(CONFIG_NETFILTER) += netfilter/
......
/*
* IP Payload Compression Protocol (IPComp) - RFC3713.
*
* Copyright (c) 2003 James Morris <jmorris@intercode.com.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.
*
* Todo:
* - Tunable compression parameters.
* - Compression stats.
* - Adaptive compression.
*/
#include <linux/config.h>
#include <linux/module.h>
#include <asm/scatterlist.h>
#include <linux/crypto.h>
#include <linux/pfkeyv2.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/icmp.h>
#include <net/esp.h>
#define IPCOMP_SCRATCH_SIZE 65400
struct ipcomp_hdr {
u8 nexthdr;
u8 flags;
u16 cpi;
};
struct ipcomp_data {
u16 threshold;
u8 *scratch;
struct crypto_tfm *tfm;
};
static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
{
int err, plen, dlen;
struct iphdr *iph;
struct ipcomp_data *ipcd = x->data;
u8 *start, *scratch = ipcd->scratch;
plen = skb->len;
dlen = IPCOMP_SCRATCH_SIZE;
start = skb->data;
err = crypto_comp_decompress(ipcd->tfm, start, plen, scratch, &dlen);
if (err)
goto out;
if (dlen < (plen + sizeof(struct ipcomp_hdr))) {
err = -EINVAL;
goto out;
}
err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
if (err)
goto out;
skb_put(skb, dlen - plen);
memcpy(skb->data, scratch, dlen);
iph = skb->nh.iph;
iph->tot_len = htons(dlen + iph->ihl * 4);
out:
return err;
}
static int ipcomp_input(struct xfrm_state *x,
struct xfrm_decap_state *decap, struct sk_buff *skb)
{
u8 nexthdr;
int err = 0;
struct iphdr *iph;
union {
struct iphdr iph;
char buf[60];
} tmp_iph;
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.iph;
memcpy(&tmp_iph, iph, iph->ihl * 4);
nexthdr = *(u8 *)skb->data;
skb_pull(skb, sizeof(struct ipcomp_hdr));
memcpy(skb->nh.raw, &tmp_iph, tmp_iph.iph.ihl * 4);
iph->tot_len = htons(ntohs(iph->tot_len) - sizeof(struct ipcomp_hdr));
iph->protocol = nexthdr;
skb->h.raw = skb->data;
err = ipcomp_decompress(x, skb);
out:
return err;
}
static int ipcomp_compress(struct xfrm_state *x, struct sk_buff *skb)
{
int err, plen, dlen, ihlen;
struct iphdr *iph = skb->nh.iph;
struct ipcomp_data *ipcd = x->data;
u8 *start, *scratch = ipcd->scratch;
ihlen = iph->ihl * 4;
plen = skb->len - ihlen;
dlen = IPCOMP_SCRATCH_SIZE;
start = skb->data + ihlen;
err = crypto_comp_compress(ipcd->tfm, start, plen, scratch, &dlen);
if (err)
goto out;
if ((dlen + sizeof(struct ipcomp_hdr)) >= plen) {
err = -EMSGSIZE;
goto out;
}
memcpy(start, scratch, dlen);
pskb_trim(skb, ihlen + dlen);
out:
return err;
}
static void ipcomp_tunnel_encap(struct xfrm_state *x,
struct sk_buff *skb, int compress)
{
struct dst_entry *dst = skb->dst;
struct iphdr *iph, *top_iph;
iph = skb->nh.iph;
top_iph = (struct iphdr *)skb_push(skb, sizeof(struct iphdr));
top_iph->ihl = 5;
top_iph->version = 4;
top_iph->tos = iph->tos;
top_iph->tot_len = htons(skb->len);
if (!(iph->frag_off&htons(IP_DF)))
__ip_select_ident(top_iph, dst, 0);
top_iph->ttl = iph->ttl;
top_iph->protocol = compress ? IPPROTO_COMP : IPPROTO_IPIP;
top_iph->check = 0;
top_iph->saddr = x->props.saddr.a4;
top_iph->daddr = x->id.daddr.a4;
top_iph->frag_off = iph->frag_off&~htons(IP_MF|IP_OFFSET);
memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
skb->nh.raw = skb->data;
}
static int ipcomp_output(struct sk_buff *skb)
{
int err;
struct dst_entry *dst = skb->dst;
struct xfrm_state *x = dst->xfrm;
struct iphdr *iph, *top_iph;
struct ipcomp_hdr *ipch;
struct ipcomp_data *ipcd = x->data;
union {
struct iphdr iph;
char buf[60];
} tmp_iph;
if (skb->ip_summed == CHECKSUM_HW && skb_checksum_help(skb) == NULL) {
err = -EINVAL;
goto error_nolock;
}
spin_lock_bh(&x->lock);
if ((err = xfrm_state_check_expire(x)) != 0)
goto error;
if ((err = xfrm_state_check_space(x, skb)) != 0)
goto error;
/* Don't bother compressing */
if (skb->len < ipcd->threshold) {
if (x->props.mode) {
ipcomp_tunnel_encap(x, skb, 0);
iph = skb->nh.iph;
ip_send_check(iph);
}
goto out_ok;
}
if (x->props.mode)
ipcomp_tunnel_encap(x, skb, 1);
if ((skb_is_nonlinear(skb) || skb_cloned(skb)) &&
skb_linearize(skb, GFP_ATOMIC) != 0) {
err = -ENOMEM;
goto error;
}
err = ipcomp_compress(x, skb);
if (err) {
if (err == -EMSGSIZE)
goto out_ok;
goto error;
}
/* Install ipcomp header, convert into ipcomp datagram. */
iph = skb->nh.iph;
memcpy(&tmp_iph, iph, iph->ihl * 4);
top_iph = (struct iphdr *)skb_push(skb, sizeof(struct ipcomp_hdr));
memcpy(top_iph, &tmp_iph, iph->ihl * 4);
iph = top_iph;
iph->tot_len = htons(skb->len);
iph->protocol = IPPROTO_COMP;
iph->check = 0;
ipch = (struct ipcomp_hdr *)((char *)iph + iph->ihl * 4);
ipch->nexthdr = x->props.mode ? IPPROTO_IPIP : tmp_iph.iph.protocol;
ipch->flags = 0;
ipch->cpi = htons((u16 )ntohl(x->id.spi));
ip_send_check(iph);
skb->nh.raw = skb->data;
out_ok:
x->curlft.bytes += skb->len;
x->curlft.packets++;
spin_unlock_bh(&x->lock);
if ((skb->dst = dst_pop(dst)) == NULL) {
err = -EHOSTUNREACH;
goto error_nolock;
}
err = NET_XMIT_BYPASS;
out_exit:
return err;
error:
spin_unlock_bh(&x->lock);
error_nolock:
kfree_skb(skb);
goto out_exit;
}
static void ipcomp4_err(struct sk_buff *skb, u32 info)
{
u32 spi;
struct iphdr *iph = (struct iphdr *)skb->data;
struct ipcomp_hdr *ipch = (struct ipcomp_hdr *)(skb->data+(iph->ihl<<2));
struct xfrm_state *x;
if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
skb->h.icmph->code != ICMP_FRAG_NEEDED)
return;
spi = ntohl(ntohs(ipch->cpi));
x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr,
spi, IPPROTO_COMP, AF_INET);
if (!x)
return;
printk(KERN_DEBUG "pmtu discvovery on SA IPCOMP/%08x/%u.%u.%u.%u\n",
spi, NIPQUAD(iph->daddr));
xfrm_state_put(x);
}
static void ipcomp_free_data(struct ipcomp_data *ipcd)
{
if (ipcd->tfm)
crypto_free_tfm(ipcd->tfm);
if (ipcd->scratch)
kfree(ipcd->scratch);
}
static void ipcomp_destroy(struct xfrm_state *x)
{
struct ipcomp_data *ipcd = x->data;
ipcomp_free_data(ipcd);
kfree(ipcd);
}
static int ipcomp_init_state(struct xfrm_state *x, void *args)
{
int err = -ENOMEM;
struct ipcomp_data *ipcd;
struct xfrm_algo_desc *calg_desc;
ipcd = kmalloc(sizeof(*ipcd), GFP_KERNEL);
if (!ipcd)
goto error;
memset(ipcd, 0, sizeof(*ipcd));
x->props.header_len = sizeof(struct ipcomp_hdr);
if (x->props.mode)
x->props.header_len += sizeof(struct iphdr);
x->data = ipcd;
ipcd->scratch = kmalloc(IPCOMP_SCRATCH_SIZE, GFP_KERNEL);
if (!ipcd->scratch)
goto error;
ipcd->tfm = crypto_alloc_tfm(x->calg->alg_name, 0);
if (!ipcd->tfm)
goto error;
calg_desc = xfrm_calg_get_byname(x->calg->alg_name);
BUG_ON(!calg_desc);
ipcd->threshold = calg_desc->uinfo.comp.threshold;
err = 0;
out:
return err;
error:
if (ipcd) {
ipcomp_free_data(ipcd);
kfree(ipcd);
}
goto out;
}
static struct xfrm_type ipcomp_type =
{
.description = "IPCOMP4",
.proto = IPPROTO_COMP,
.init_state = ipcomp_init_state,
.destructor = ipcomp_destroy,
.input = ipcomp_input,
.output = ipcomp_output
};
static struct inet_protocol ipcomp4_protocol = {
.handler = xfrm4_rcv,
.err_handler = ipcomp4_err,
.no_policy = 1,
};
static int __init ipcomp4_init(void)
{
SET_MODULE_OWNER(&ipcomp_type);
if (xfrm_register_type(&ipcomp_type, AF_INET) < 0) {
printk(KERN_INFO "ipcomp init: can't add xfrm type\n");
return -EAGAIN;
}
if (inet_add_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0) {
printk(KERN_INFO "ipcomp init: can't add protocol\n");
xfrm_unregister_type(&ipcomp_type, AF_INET);
return -EAGAIN;
}
return 0;
}
static void __exit ipcomp4_fini(void)
{
if (inet_del_protocol(&ipcomp4_protocol, IPPROTO_COMP) < 0)
printk(KERN_INFO "ip ipcomp close: can't remove protocol\n");
if (xfrm_unregister_type(&ipcomp_type, AF_INET) < 0)
printk(KERN_INFO "ip ipcomp close: can't remove xfrm type\n");
}
module_init(ipcomp4_init);
module_exit(ipcomp4_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) - RFC3713");
MODULE_AUTHOR("James Morris <jmorris@intercode.com.au>");
......@@ -201,6 +201,13 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl)
}
break;
case IPPROTO_COMP:
if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
u16 *ipcomp_hdr = (u16 *)xprth;
fl->uli_u.spi = ntohl(ntohs(ipcomp_hdr[1]));
}
break;
default:
fl->uli_u.spi = 0;
break;
......
......@@ -203,6 +203,7 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl)
/* XXX Why are there these headers? */
case IPPROTO_AH:
case IPPROTO_ESP:
case IPPROTO_COMP:
default:
fl->uli_u.spi = 0;
return;
......
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