Contributors: 23
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Patrick McHardy |
700 |
40.05% |
8 |
11.94% |
| Florian Westphal |
414 |
23.68% |
15 |
22.39% |
| Pablo Neira Ayuso |
288 |
16.48% |
8 |
11.94% |
| Gao Feng |
113 |
6.46% |
4 |
5.97% |
| Alexey Dobriyan |
68 |
3.89% |
2 |
2.99% |
| Yasuyuki Kozakai |
54 |
3.09% |
1 |
1.49% |
| Harald Welte |
23 |
1.32% |
4 |
5.97% |
| Linus Torvalds (pre-git) |
20 |
1.14% |
8 |
11.94% |
| Jan Engelhardt |
15 |
0.86% |
3 |
4.48% |
| Thomas Graf |
13 |
0.74% |
1 |
1.49% |
| David S. Miller |
9 |
0.51% |
1 |
1.49% |
| Eric W. Biedermann |
5 |
0.29% |
1 |
1.49% |
| Holger Eitzenberger |
5 |
0.29% |
1 |
1.49% |
| Faicker Mo |
5 |
0.29% |
1 |
1.49% |
| Cyrill V. Gorcunov |
4 |
0.23% |
1 |
1.49% |
| Rusty Russell |
4 |
0.23% |
1 |
1.49% |
| Steven Rostedt |
2 |
0.11% |
1 |
1.49% |
| Thomas Gleixner |
1 |
0.06% |
1 |
1.49% |
| Igor Maravić |
1 |
0.06% |
1 |
1.49% |
| Yonatan Goldschmidt |
1 |
0.06% |
1 |
1.49% |
| Martin Josefsson |
1 |
0.06% |
1 |
1.49% |
| Kees Cook |
1 |
0.06% |
1 |
1.49% |
| Linus Torvalds |
1 |
0.06% |
1 |
1.49% |
| Total |
1748 |
|
67 |
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* 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/)
*
* (C) 2006-2012 Patrick McHardy <kaber@trash.net>
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/list.h>
#include <linux/seq_file.h>
#include <linux/in.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <net/dst.h>
#include <net/gre.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_timeout.h>
#include <net/pptp.h>
#include <linux/netfilter/nf_conntrack_proto_gre.h>
#include <linux/netfilter/nf_conntrack_pptp.h>
static const unsigned int gre_timeouts[GRE_CT_MAX] = {
[GRE_CT_UNREPLIED] = 30*HZ,
[GRE_CT_REPLIED] = 180*HZ,
};
/* used when expectation is added */
static DEFINE_SPINLOCK(keymap_lock);
static inline struct nf_gre_net *gre_pernet(struct net *net)
{
return &net->ct.nf_ct_proto.gre;
}
static inline int gre_key_cmpfn(const struct nf_ct_gre_keymap *km,
const struct nf_conntrack_tuple *t)
{
return km->tuple.src.l3num == t->src.l3num &&
!memcmp(&km->tuple.src.u3, &t->src.u3, sizeof(t->src.u3)) &&
!memcmp(&km->tuple.dst.u3, &t->dst.u3, sizeof(t->dst.u3)) &&
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 net *net, struct nf_conntrack_tuple *t)
{
struct nf_gre_net *net_gre = gre_pernet(net);
struct nf_ct_gre_keymap *km;
__be16 key = 0;
list_for_each_entry_rcu(km, &net_gre->keymap_list, list) {
if (gre_key_cmpfn(km, t)) {
key = km->tuple.src.u.gre.key;
break;
}
}
pr_debug("lookup src key 0x%x for ", key);
nf_ct_dump_tuple(t);
return key;
}
enum nf_ct_gre_km_act {
NF_CT_GRE_KM_NEW,
NF_CT_GRE_KM_BAD,
NF_CT_GRE_KM_DUP
};
static enum nf_ct_gre_km_act
nf_ct_gre_km_acceptable(const struct nf_ct_pptp_master *ct_pptp_info,
const struct nf_conntrack_tuple *orig,
const struct nf_conntrack_tuple *repl)
{
struct nf_ct_gre_keymap *km_orig, *km_repl;
lockdep_assert_held(&keymap_lock);
km_orig = ct_pptp_info->keymap[IP_CT_DIR_ORIGINAL];
km_repl = ct_pptp_info->keymap[IP_CT_DIR_REPLY];
if (km_orig && km_repl) {
if (!gre_key_cmpfn(km_orig, orig))
return NF_CT_GRE_KM_BAD;
if (!gre_key_cmpfn(km_repl, repl))
return NF_CT_GRE_KM_BAD;
return NF_CT_GRE_KM_DUP;
}
DEBUG_NET_WARN_ON_ONCE(km_orig);
DEBUG_NET_WARN_ON_ONCE(km_repl);
return NF_CT_GRE_KM_NEW;
}
/* add keymap entries, associate with specified master ct */
bool nf_ct_gre_keymap_add(struct nf_conn *ct,
const struct nf_conntrack_tuple *orig,
const struct nf_conntrack_tuple *repl)
{
struct net *net = nf_ct_net(ct);
struct nf_gre_net *net_gre = gre_pernet(net);
struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
struct nf_ct_gre_keymap *km_orig, *km_repl;
bool ret = false;
km_orig = kmalloc_obj(*km_orig, GFP_ATOMIC);
if (!km_orig)
return false;
km_repl = kmalloc_obj(*km_repl, GFP_ATOMIC);
if (!km_repl)
goto km_free;
memcpy(&km_orig->tuple, orig, sizeof(*orig));
memcpy(&km_repl->tuple, repl, sizeof(*repl));
spin_lock_bh(&keymap_lock);
if (nf_ct_is_dying(ct))
goto unlock_free;
switch (nf_ct_gre_km_acceptable(ct_pptp_info, orig, repl)) {
case NF_CT_GRE_KM_NEW:
break;
case NF_CT_GRE_KM_DUP:
ret = true;
goto unlock_free;
case NF_CT_GRE_KM_BAD:
pr_debug("trying to override keymap for ct %p\n", ct);
goto unlock_free;
}
if (ct_pptp_info->keymap[IP_CT_DIR_ORIGINAL] ||
ct_pptp_info->keymap[IP_CT_DIR_REPLY])
goto unlock_free;
pr_debug("adding new entries %p,%p: ", km_orig, km_repl);
nf_ct_dump_tuple(&km_orig->tuple);
nf_ct_dump_tuple(&km_repl->tuple);
list_add_tail_rcu(&km_orig->list, &net_gre->keymap_list);
list_add_tail_rcu(&km_repl->list, &net_gre->keymap_list);
ct_pptp_info->keymap[IP_CT_DIR_ORIGINAL] = km_orig;
ct_pptp_info->keymap[IP_CT_DIR_REPLY] = km_repl;
spin_unlock_bh(&keymap_lock);
return true;
unlock_free:
spin_unlock_bh(&keymap_lock);
km_free:
kfree(km_orig);
kfree(km_repl);
return ret;
}
EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_add);
/* destroy the keymap entries associated with specified master ct */
void nf_ct_gre_keymap_destroy(struct nf_conn *ct)
{
struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
enum ip_conntrack_dir dir;
pr_debug("entering for ct %p\n", ct);
spin_lock_bh(&keymap_lock);
for (dir = IP_CT_DIR_ORIGINAL; dir < IP_CT_DIR_MAX; dir++) {
if (ct_pptp_info->keymap[dir]) {
pr_debug("removing %p from list\n",
ct_pptp_info->keymap[dir]);
list_del_rcu(&ct_pptp_info->keymap[dir]->list);
kfree_rcu(ct_pptp_info->keymap[dir], rcu);
ct_pptp_info->keymap[dir] = NULL;
}
}
spin_unlock_bh(&keymap_lock);
}
EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_destroy);
/* PUBLIC CONNTRACK PROTO HELPER FUNCTIONS */
/* gre hdr info to tuple */
bool gre_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
struct net *net, struct nf_conntrack_tuple *tuple)
{
const struct pptp_gre_header *pgrehdr;
struct pptp_gre_header _pgrehdr;
__be16 srckey;
const struct gre_base_hdr *grehdr;
struct gre_base_hdr _grehdr;
/* first only delinearize old RFC1701 GRE header */
grehdr = skb_header_pointer(skb, dataoff, sizeof(_grehdr), &_grehdr);
if (!grehdr || (grehdr->flags & GRE_VERSION) != GRE_VERSION_1) {
/* try to behave like "nf_conntrack_proto_generic" */
tuple->src.u.all = 0;
tuple->dst.u.all = 0;
return true;
}
/* PPTP header is variable length, only need up to the call_id field */
pgrehdr = skb_header_pointer(skb, dataoff, 8, &_pgrehdr);
if (!pgrehdr)
return true;
if (grehdr->protocol != GRE_PROTO_PPP) {
pr_debug("Unsupported GRE proto(0x%x)\n", ntohs(grehdr->protocol));
return false;
}
tuple->dst.u.gre.key = pgrehdr->call_id;
srckey = gre_keymap_lookup(net, tuple);
tuple->src.u.gre.key = srckey;
return true;
}
#ifdef CONFIG_NF_CONNTRACK_PROCFS
/* print private data for conntrack */
static void gre_print_conntrack(struct seq_file *s, struct nf_conn *ct)
{
seq_printf(s, "timeout=%u, stream_timeout=%u ",
(ct->proto.gre.timeout / HZ),
(ct->proto.gre.stream_timeout / HZ));
}
#endif
static unsigned int *gre_get_timeouts(struct net *net)
{
return gre_pernet(net)->timeouts;
}
/* Returns verdict for packet, and may modify conntrack */
int nf_conntrack_gre_packet(struct nf_conn *ct,
struct sk_buff *skb,
unsigned int dataoff,
enum ip_conntrack_info ctinfo,
const struct nf_hook_state *state)
{
unsigned long status;
if (!nf_ct_is_confirmed(ct)) {
unsigned int *timeouts = nf_ct_timeout_lookup(ct);
if (!timeouts)
timeouts = gre_get_timeouts(nf_ct_net(ct));
/* initialize to sane value. Ideally a conntrack helper
* (e.g. in case of pptp) is increasing them */
ct->proto.gre.stream_timeout = timeouts[GRE_CT_REPLIED];
ct->proto.gre.timeout = timeouts[GRE_CT_UNREPLIED];
}
status = READ_ONCE(ct->status);
/* If we've seen traffic both ways, this is a GRE connection.
* Extend timeout. */
if (status & IPS_SEEN_REPLY) {
nf_ct_refresh_acct(ct, ctinfo, skb,
ct->proto.gre.stream_timeout);
/* never set ASSURED for IPS_NAT_CLASH, they time out soon */
if (unlikely((status & IPS_NAT_CLASH)))
return NF_ACCEPT;
/* Also, more likely to be important, and not a probe. */
if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
nf_conntrack_event_cache(IPCT_ASSURED, ct);
} else
nf_ct_refresh_acct(ct, ctinfo, skb,
ct->proto.gre.timeout);
return NF_ACCEPT;
}
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_cttimeout.h>
static int gre_timeout_nlattr_to_obj(struct nlattr *tb[],
struct net *net, void *data)
{
unsigned int *timeouts = data;
struct nf_gre_net *net_gre = gre_pernet(net);
if (!timeouts)
timeouts = gre_get_timeouts(net);
/* set default timeouts for GRE. */
timeouts[GRE_CT_UNREPLIED] = net_gre->timeouts[GRE_CT_UNREPLIED];
timeouts[GRE_CT_REPLIED] = net_gre->timeouts[GRE_CT_REPLIED];
if (tb[CTA_TIMEOUT_GRE_UNREPLIED]) {
timeouts[GRE_CT_UNREPLIED] =
ntohl(nla_get_be32(tb[CTA_TIMEOUT_GRE_UNREPLIED])) * HZ;
}
if (tb[CTA_TIMEOUT_GRE_REPLIED]) {
timeouts[GRE_CT_REPLIED] =
ntohl(nla_get_be32(tb[CTA_TIMEOUT_GRE_REPLIED])) * HZ;
}
return 0;
}
static int
gre_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
{
const unsigned int *timeouts = data;
if (nla_put_be32(skb, CTA_TIMEOUT_GRE_UNREPLIED,
htonl(timeouts[GRE_CT_UNREPLIED] / HZ)) ||
nla_put_be32(skb, CTA_TIMEOUT_GRE_REPLIED,
htonl(timeouts[GRE_CT_REPLIED] / HZ)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -ENOSPC;
}
static const struct nla_policy
gre_timeout_nla_policy[CTA_TIMEOUT_GRE_MAX+1] = {
[CTA_TIMEOUT_GRE_UNREPLIED] = { .type = NLA_U32 },
[CTA_TIMEOUT_GRE_REPLIED] = { .type = NLA_U32 },
};
#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
void nf_conntrack_gre_init_net(struct net *net)
{
struct nf_gre_net *net_gre = gre_pernet(net);
int i;
INIT_LIST_HEAD(&net_gre->keymap_list);
for (i = 0; i < GRE_CT_MAX; i++)
net_gre->timeouts[i] = gre_timeouts[i];
}
/* protocol helper struct */
const struct nf_conntrack_l4proto nf_conntrack_l4proto_gre = {
.l4proto = IPPROTO_GRE,
.allow_clash = true,
#ifdef CONFIG_NF_CONNTRACK_PROCFS
.print_conntrack = gre_print_conntrack,
#endif
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
.nla_policy = nf_ct_port_nla_policy,
#endif
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
.ctnl_timeout = {
.nlattr_to_obj = gre_timeout_nlattr_to_obj,
.obj_to_nlattr = gre_timeout_obj_to_nlattr,
.nlattr_max = CTA_TIMEOUT_GRE_MAX,
.obj_size = sizeof(unsigned int) * GRE_CT_MAX,
.nla_policy = gre_timeout_nla_policy,
},
#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
};