mirror of
https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
synced 2024-10-19 09:59:04 +00:00
65195686ff
Signed-off-by: Patrick McHardy <kaber@trash.net>
328 lines
8.9 KiB
C
328 lines
8.9 KiB
C
/*
|
|
* ip_conntrack_proto_gre.c - Version 3.0
|
|
*
|
|
* Connection tracking protocol helper module for GRE.
|
|
*
|
|
* GRE is a generic encapsulation protocol, which is generally not very
|
|
* suited for NAT, as it has no protocol-specific part as port numbers.
|
|
*
|
|
* It has an optional key field, which may help us distinguishing two
|
|
* connections between the same two hosts.
|
|
*
|
|
* GRE is defined in RFC 1701 and RFC 1702, as well as RFC 2784
|
|
*
|
|
* PPTP is built on top of a modified version of GRE, and has a mandatory
|
|
* field called "CallID", which serves us for the same purpose as the key
|
|
* field in plain GRE.
|
|
*
|
|
* Documentation about PPTP can be found in RFC 2637
|
|
*
|
|
* (C) 2000-2005 by Harald Welte <laforge@gnumonks.org>
|
|
*
|
|
* Development of this code funded by Astaro AG (http://www.astaro.com/)
|
|
*
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/types.h>
|
|
#include <linux/timer.h>
|
|
#include <linux/netfilter.h>
|
|
#include <linux/ip.h>
|
|
#include <linux/in.h>
|
|
#include <linux/list.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/interrupt.h>
|
|
|
|
static DEFINE_RWLOCK(ip_ct_gre_lock);
|
|
|
|
#include <linux/netfilter_ipv4/ip_conntrack_protocol.h>
|
|
#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
|
|
#include <linux/netfilter_ipv4/ip_conntrack_core.h>
|
|
|
|
#include <linux/netfilter_ipv4/ip_conntrack_proto_gre.h>
|
|
#include <linux/netfilter_ipv4/ip_conntrack_pptp.h>
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
|
|
MODULE_DESCRIPTION("netfilter connection tracking protocol helper for GRE");
|
|
|
|
/* shamelessly stolen from ip_conntrack_proto_udp.c */
|
|
#define GRE_TIMEOUT (30*HZ)
|
|
#define GRE_STREAM_TIMEOUT (180*HZ)
|
|
|
|
#if 0
|
|
#define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s: " format, __FILE__, __FUNCTION__, ## args)
|
|
#define DUMP_TUPLE_GRE(x) printk("%u.%u.%u.%u:0x%x -> %u.%u.%u.%u:0x%x\n", \
|
|
NIPQUAD((x)->src.ip), ntohs((x)->src.u.gre.key), \
|
|
NIPQUAD((x)->dst.ip), ntohs((x)->dst.u.gre.key))
|
|
#else
|
|
#define DEBUGP(x, args...)
|
|
#define DUMP_TUPLE_GRE(x)
|
|
#endif
|
|
|
|
/* GRE KEYMAP HANDLING FUNCTIONS */
|
|
static LIST_HEAD(gre_keymap_list);
|
|
|
|
static inline int gre_key_cmpfn(const struct ip_ct_gre_keymap *km,
|
|
const struct ip_conntrack_tuple *t)
|
|
{
|
|
return ((km->tuple.src.ip == t->src.ip) &&
|
|
(km->tuple.dst.ip == t->dst.ip) &&
|
|
(km->tuple.dst.protonum == t->dst.protonum) &&
|
|
(km->tuple.dst.u.all == t->dst.u.all));
|
|
}
|
|
|
|
/* look up the source key for a given tuple */
|
|
static __be16 gre_keymap_lookup(struct ip_conntrack_tuple *t)
|
|
{
|
|
struct ip_ct_gre_keymap *km;
|
|
__be16 key = 0;
|
|
|
|
read_lock_bh(&ip_ct_gre_lock);
|
|
list_for_each_entry(km, &gre_keymap_list, list) {
|
|
if (gre_key_cmpfn(km, t)) {
|
|
key = km->tuple.src.u.gre.key;
|
|
break;
|
|
}
|
|
}
|
|
read_unlock_bh(&ip_ct_gre_lock);
|
|
|
|
DEBUGP("lookup src key 0x%x up key for ", key);
|
|
DUMP_TUPLE_GRE(t);
|
|
|
|
return key;
|
|
}
|
|
|
|
/* add a single keymap entry, associate with specified master ct */
|
|
int
|
|
ip_ct_gre_keymap_add(struct ip_conntrack *ct,
|
|
struct ip_conntrack_tuple *t, int reply)
|
|
{
|
|
struct ip_ct_gre_keymap **exist_km, *km;
|
|
|
|
if (!ct->helper || strcmp(ct->helper->name, "pptp")) {
|
|
DEBUGP("refusing to add GRE keymap to non-pptp session\n");
|
|
return -1;
|
|
}
|
|
|
|
if (!reply)
|
|
exist_km = &ct->help.ct_pptp_info.keymap_orig;
|
|
else
|
|
exist_km = &ct->help.ct_pptp_info.keymap_reply;
|
|
|
|
if (*exist_km) {
|
|
/* check whether it's a retransmission */
|
|
list_for_each_entry(km, &gre_keymap_list, list) {
|
|
if (gre_key_cmpfn(km, t) && km == *exist_km)
|
|
return 0;
|
|
}
|
|
DEBUGP("trying to override keymap_%s for ct %p\n",
|
|
reply? "reply":"orig", ct);
|
|
return -EEXIST;
|
|
}
|
|
|
|
km = kmalloc(sizeof(*km), GFP_ATOMIC);
|
|
if (!km)
|
|
return -ENOMEM;
|
|
|
|
memcpy(&km->tuple, t, sizeof(*t));
|
|
*exist_km = km;
|
|
|
|
DEBUGP("adding new entry %p: ", km);
|
|
DUMP_TUPLE_GRE(&km->tuple);
|
|
|
|
write_lock_bh(&ip_ct_gre_lock);
|
|
list_add_tail(&km->list, &gre_keymap_list);
|
|
write_unlock_bh(&ip_ct_gre_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* destroy the keymap entries associated with specified master ct */
|
|
void ip_ct_gre_keymap_destroy(struct ip_conntrack *ct)
|
|
{
|
|
DEBUGP("entering for ct %p\n", ct);
|
|
|
|
if (!ct->helper || strcmp(ct->helper->name, "pptp")) {
|
|
DEBUGP("refusing to destroy GRE keymap to non-pptp session\n");
|
|
return;
|
|
}
|
|
|
|
write_lock_bh(&ip_ct_gre_lock);
|
|
if (ct->help.ct_pptp_info.keymap_orig) {
|
|
DEBUGP("removing %p from list\n",
|
|
ct->help.ct_pptp_info.keymap_orig);
|
|
list_del(&ct->help.ct_pptp_info.keymap_orig->list);
|
|
kfree(ct->help.ct_pptp_info.keymap_orig);
|
|
ct->help.ct_pptp_info.keymap_orig = NULL;
|
|
}
|
|
if (ct->help.ct_pptp_info.keymap_reply) {
|
|
DEBUGP("removing %p from list\n",
|
|
ct->help.ct_pptp_info.keymap_reply);
|
|
list_del(&ct->help.ct_pptp_info.keymap_reply->list);
|
|
kfree(ct->help.ct_pptp_info.keymap_reply);
|
|
ct->help.ct_pptp_info.keymap_reply = NULL;
|
|
}
|
|
write_unlock_bh(&ip_ct_gre_lock);
|
|
}
|
|
|
|
|
|
/* PUBLIC CONNTRACK PROTO HELPER FUNCTIONS */
|
|
|
|
/* invert gre part of tuple */
|
|
static int gre_invert_tuple(struct ip_conntrack_tuple *tuple,
|
|
const struct ip_conntrack_tuple *orig)
|
|
{
|
|
tuple->dst.u.gre.key = orig->src.u.gre.key;
|
|
tuple->src.u.gre.key = orig->dst.u.gre.key;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* gre hdr info to tuple */
|
|
static int gre_pkt_to_tuple(const struct sk_buff *skb,
|
|
unsigned int dataoff,
|
|
struct ip_conntrack_tuple *tuple)
|
|
{
|
|
struct gre_hdr_pptp _pgrehdr, *pgrehdr;
|
|
__be16 srckey;
|
|
struct gre_hdr _grehdr, *grehdr;
|
|
|
|
/* first only delinearize old RFC1701 GRE header */
|
|
grehdr = skb_header_pointer(skb, dataoff, sizeof(_grehdr), &_grehdr);
|
|
if (!grehdr || grehdr->version != GRE_VERSION_PPTP) {
|
|
/* try to behave like "ip_conntrack_proto_generic" */
|
|
tuple->src.u.all = 0;
|
|
tuple->dst.u.all = 0;
|
|
return 1;
|
|
}
|
|
|
|
/* PPTP header is variable length, only need up to the call_id field */
|
|
pgrehdr = skb_header_pointer(skb, dataoff, 8, &_pgrehdr);
|
|
if (!pgrehdr)
|
|
return 1;
|
|
|
|
if (ntohs(grehdr->protocol) != GRE_PROTOCOL_PPTP) {
|
|
DEBUGP("GRE_VERSION_PPTP but unknown proto\n");
|
|
return 0;
|
|
}
|
|
|
|
tuple->dst.u.gre.key = pgrehdr->call_id;
|
|
srckey = gre_keymap_lookup(tuple);
|
|
tuple->src.u.gre.key = srckey;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* print gre part of tuple */
|
|
static int gre_print_tuple(struct seq_file *s,
|
|
const struct ip_conntrack_tuple *tuple)
|
|
{
|
|
return seq_printf(s, "srckey=0x%x dstkey=0x%x ",
|
|
ntohs(tuple->src.u.gre.key),
|
|
ntohs(tuple->dst.u.gre.key));
|
|
}
|
|
|
|
/* print private data for conntrack */
|
|
static int gre_print_conntrack(struct seq_file *s,
|
|
const struct ip_conntrack *ct)
|
|
{
|
|
return seq_printf(s, "timeout=%u, stream_timeout=%u ",
|
|
(ct->proto.gre.timeout / HZ),
|
|
(ct->proto.gre.stream_timeout / HZ));
|
|
}
|
|
|
|
/* Returns verdict for packet, and may modify conntrack */
|
|
static int gre_packet(struct ip_conntrack *ct,
|
|
const struct sk_buff *skb,
|
|
enum ip_conntrack_info conntrackinfo)
|
|
{
|
|
/* If we've seen traffic both ways, this is a GRE connection.
|
|
* Extend timeout. */
|
|
if (ct->status & IPS_SEEN_REPLY) {
|
|
ip_ct_refresh_acct(ct, conntrackinfo, skb,
|
|
ct->proto.gre.stream_timeout);
|
|
/* Also, more likely to be important, and not a probe. */
|
|
set_bit(IPS_ASSURED_BIT, &ct->status);
|
|
ip_conntrack_event_cache(IPCT_STATUS, skb);
|
|
} else
|
|
ip_ct_refresh_acct(ct, conntrackinfo, skb,
|
|
ct->proto.gre.timeout);
|
|
|
|
return NF_ACCEPT;
|
|
}
|
|
|
|
/* Called when a new connection for this protocol found. */
|
|
static int gre_new(struct ip_conntrack *ct,
|
|
const struct sk_buff *skb)
|
|
{
|
|
DEBUGP(": ");
|
|
DUMP_TUPLE_GRE(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
|
|
|
|
/* initialize to sane value. Ideally a conntrack helper
|
|
* (e.g. in case of pptp) is increasing them */
|
|
ct->proto.gre.stream_timeout = GRE_STREAM_TIMEOUT;
|
|
ct->proto.gre.timeout = GRE_TIMEOUT;
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* Called when a conntrack entry has already been removed from the hashes
|
|
* and is about to be deleted from memory */
|
|
static void gre_destroy(struct ip_conntrack *ct)
|
|
{
|
|
struct ip_conntrack *master = ct->master;
|
|
DEBUGP(" entering\n");
|
|
|
|
if (!master)
|
|
DEBUGP("no master !?!\n");
|
|
else
|
|
ip_ct_gre_keymap_destroy(master);
|
|
}
|
|
|
|
/* protocol helper struct */
|
|
static struct ip_conntrack_protocol gre = {
|
|
.proto = IPPROTO_GRE,
|
|
.name = "gre",
|
|
.pkt_to_tuple = gre_pkt_to_tuple,
|
|
.invert_tuple = gre_invert_tuple,
|
|
.print_tuple = gre_print_tuple,
|
|
.print_conntrack = gre_print_conntrack,
|
|
.packet = gre_packet,
|
|
.new = gre_new,
|
|
.destroy = gre_destroy,
|
|
.me = THIS_MODULE,
|
|
#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
|
|
defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
|
|
.tuple_to_nfattr = ip_ct_port_tuple_to_nfattr,
|
|
.nfattr_to_tuple = ip_ct_port_nfattr_to_tuple,
|
|
#endif
|
|
};
|
|
|
|
/* ip_conntrack_proto_gre initialization */
|
|
int __init ip_ct_proto_gre_init(void)
|
|
{
|
|
return ip_conntrack_protocol_register(&gre);
|
|
}
|
|
|
|
/* This cannot be __exit, as it is invoked from ip_conntrack_helper_pptp.c's
|
|
* init() code on errors.
|
|
*/
|
|
void ip_ct_proto_gre_fini(void)
|
|
{
|
|
struct list_head *pos, *n;
|
|
|
|
/* delete all keymap entries */
|
|
write_lock_bh(&ip_ct_gre_lock);
|
|
list_for_each_safe(pos, n, &gre_keymap_list) {
|
|
DEBUGP("deleting keymap %p at module unload time\n", pos);
|
|
list_del(pos);
|
|
kfree(pos);
|
|
}
|
|
write_unlock_bh(&ip_ct_gre_lock);
|
|
|
|
ip_conntrack_protocol_unregister(&gre);
|
|
}
|
|
|
|
EXPORT_SYMBOL(ip_ct_gre_keymap_add);
|
|
EXPORT_SYMBOL(ip_ct_gre_keymap_destroy);
|