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337fbc4166
The NAT helpr hooks are protected by RCU, but all of the conntrack helpers test and use the global pointers instead of copying them first using rcu_dereference() Also replace synchronize_net() by synchronize_rcu() for clarity since sychronizing only with packet receive processing is insufficient to prevent races. Signed-off-by: Patrick McHardy <kaber@trash.net>
684 lines
20 KiB
C
684 lines
20 KiB
C
/*
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* ip_conntrack_pptp.c - Version 3.0
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*
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* Connection tracking support for PPTP (Point to Point Tunneling Protocol).
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* PPTP is a a protocol for creating virtual private networks.
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* It is a specification defined by Microsoft and some vendors
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* working with Microsoft. PPTP is built on top of a modified
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* version of the Internet Generic Routing Encapsulation Protocol.
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* GRE is defined in RFC 1701 and RFC 1702. Documentation of
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* PPTP can be found in RFC 2637
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*
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* (C) 2000-2005 by Harald Welte <laforge@gnumonks.org>
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*
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* Development of this code funded by Astaro AG (http://www.astaro.com/)
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*
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* Limitations:
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* - We blindly assume that control connections are always
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* established in PNS->PAC direction. This is a violation
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* of RFFC2673
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* - We can only support one single call within each session
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*
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* TODO:
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* - testing of incoming PPTP calls
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*
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* Changes:
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* 2002-02-05 - Version 1.3
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* - Call ip_conntrack_unexpect_related() from
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* pptp_destroy_siblings() to destroy expectations in case
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* CALL_DISCONNECT_NOTIFY or tcp fin packet was seen
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* (Philip Craig <philipc@snapgear.com>)
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* - Add Version information at module loadtime
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* 2002-02-10 - Version 1.6
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* - move to C99 style initializers
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* - remove second expectation if first arrives
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* 2004-10-22 - Version 2.0
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* - merge Mandrake's 2.6.x port with recent 2.6.x API changes
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* - fix lots of linear skb assumptions from Mandrake's port
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* 2005-06-10 - Version 2.1
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* - use ip_conntrack_expect_free() instead of kfree() on the
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* expect's (which are from the slab for quite some time)
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* 2005-06-10 - Version 3.0
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* - port helper to post-2.6.11 API changes,
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* funded by Oxcoda NetBox Blue (http://www.netboxblue.com/)
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* 2005-07-30 - Version 3.1
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* - port helper to 2.6.13 API changes
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*
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*/
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#include <linux/module.h>
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#include <linux/netfilter.h>
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#include <linux/ip.h>
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#include <net/checksum.h>
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#include <net/tcp.h>
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#include <linux/netfilter_ipv4/ip_conntrack.h>
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#include <linux/netfilter_ipv4/ip_conntrack_core.h>
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#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
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#include <linux/netfilter_ipv4/ip_conntrack_proto_gre.h>
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#include <linux/netfilter_ipv4/ip_conntrack_pptp.h>
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#define IP_CT_PPTP_VERSION "3.1"
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
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MODULE_DESCRIPTION("Netfilter connection tracking helper module for PPTP");
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static DEFINE_SPINLOCK(ip_pptp_lock);
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int
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(*ip_nat_pptp_hook_outbound)(struct sk_buff **pskb,
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struct ip_conntrack *ct,
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enum ip_conntrack_info ctinfo,
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struct PptpControlHeader *ctlh,
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union pptp_ctrl_union *pptpReq);
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int
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(*ip_nat_pptp_hook_inbound)(struct sk_buff **pskb,
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struct ip_conntrack *ct,
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enum ip_conntrack_info ctinfo,
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struct PptpControlHeader *ctlh,
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union pptp_ctrl_union *pptpReq);
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void
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(*ip_nat_pptp_hook_exp_gre)(struct ip_conntrack_expect *expect_orig,
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struct ip_conntrack_expect *expect_reply);
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void
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(*ip_nat_pptp_hook_expectfn)(struct ip_conntrack *ct,
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struct ip_conntrack_expect *exp);
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#if 0
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/* PptpControlMessageType names */
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const char *pptp_msg_name[] = {
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"UNKNOWN_MESSAGE",
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"START_SESSION_REQUEST",
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"START_SESSION_REPLY",
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"STOP_SESSION_REQUEST",
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"STOP_SESSION_REPLY",
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"ECHO_REQUEST",
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"ECHO_REPLY",
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"OUT_CALL_REQUEST",
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"OUT_CALL_REPLY",
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"IN_CALL_REQUEST",
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"IN_CALL_REPLY",
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"IN_CALL_CONNECT",
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"CALL_CLEAR_REQUEST",
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"CALL_DISCONNECT_NOTIFY",
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"WAN_ERROR_NOTIFY",
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"SET_LINK_INFO"
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};
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EXPORT_SYMBOL(pptp_msg_name);
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#define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s: " format, __FILE__, __FUNCTION__, ## args)
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#else
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#define DEBUGP(format, args...)
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#endif
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#define SECS *HZ
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#define MINS * 60 SECS
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#define HOURS * 60 MINS
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#define PPTP_GRE_TIMEOUT (10 MINS)
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#define PPTP_GRE_STREAM_TIMEOUT (5 HOURS)
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static void pptp_expectfn(struct ip_conntrack *ct,
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struct ip_conntrack_expect *exp)
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{
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typeof(ip_nat_pptp_hook_expectfn) ip_nat_pptp_expectfn;
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DEBUGP("increasing timeouts\n");
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/* increase timeout of GRE data channel conntrack entry */
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ct->proto.gre.timeout = PPTP_GRE_TIMEOUT;
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ct->proto.gre.stream_timeout = PPTP_GRE_STREAM_TIMEOUT;
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/* Can you see how rusty this code is, compared with the pre-2.6.11
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* one? That's what happened to my shiny newnat of 2002 ;( -HW */
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rcu_read_lock();
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ip_nat_pptp_expectfn = rcu_dereference(ip_nat_pptp_hook_expectfn);
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if (!ip_nat_pptp_expectfn) {
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struct ip_conntrack_tuple inv_t;
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struct ip_conntrack_expect *exp_other;
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/* obviously this tuple inversion only works until you do NAT */
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invert_tuplepr(&inv_t, &exp->tuple);
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DEBUGP("trying to unexpect other dir: ");
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DUMP_TUPLE(&inv_t);
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exp_other = ip_conntrack_expect_find_get(&inv_t);
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if (exp_other) {
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/* delete other expectation. */
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DEBUGP("found\n");
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ip_conntrack_unexpect_related(exp_other);
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ip_conntrack_expect_put(exp_other);
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} else {
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DEBUGP("not found\n");
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}
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} else {
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/* we need more than simple inversion */
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ip_nat_pptp_expectfn(ct, exp);
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}
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rcu_read_unlock();
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}
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static int destroy_sibling_or_exp(const struct ip_conntrack_tuple *t)
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{
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struct ip_conntrack_tuple_hash *h;
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struct ip_conntrack_expect *exp;
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DEBUGP("trying to timeout ct or exp for tuple ");
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DUMP_TUPLE(t);
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h = ip_conntrack_find_get(t, NULL);
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if (h) {
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struct ip_conntrack *sibling = tuplehash_to_ctrack(h);
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DEBUGP("setting timeout of conntrack %p to 0\n", sibling);
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sibling->proto.gre.timeout = 0;
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sibling->proto.gre.stream_timeout = 0;
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if (del_timer(&sibling->timeout))
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sibling->timeout.function((unsigned long)sibling);
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ip_conntrack_put(sibling);
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return 1;
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} else {
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exp = ip_conntrack_expect_find_get(t);
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if (exp) {
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DEBUGP("unexpect_related of expect %p\n", exp);
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ip_conntrack_unexpect_related(exp);
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ip_conntrack_expect_put(exp);
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return 1;
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}
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}
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return 0;
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}
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/* timeout GRE data connections */
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static void pptp_destroy_siblings(struct ip_conntrack *ct)
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{
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struct ip_conntrack_tuple t;
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ip_ct_gre_keymap_destroy(ct);
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/* Since ct->sibling_list has literally rusted away in 2.6.11,
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* we now need another way to find out about our sibling
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* contrack and expects... -HW */
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/* try original (pns->pac) tuple */
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memcpy(&t, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, sizeof(t));
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t.dst.protonum = IPPROTO_GRE;
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t.src.u.gre.key = ct->help.ct_pptp_info.pns_call_id;
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t.dst.u.gre.key = ct->help.ct_pptp_info.pac_call_id;
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if (!destroy_sibling_or_exp(&t))
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DEBUGP("failed to timeout original pns->pac ct/exp\n");
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/* try reply (pac->pns) tuple */
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memcpy(&t, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, sizeof(t));
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t.dst.protonum = IPPROTO_GRE;
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t.src.u.gre.key = ct->help.ct_pptp_info.pac_call_id;
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t.dst.u.gre.key = ct->help.ct_pptp_info.pns_call_id;
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if (!destroy_sibling_or_exp(&t))
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DEBUGP("failed to timeout reply pac->pns ct/exp\n");
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}
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/* expect GRE connections (PNS->PAC and PAC->PNS direction) */
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static inline int
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exp_gre(struct ip_conntrack *ct,
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__be16 callid,
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__be16 peer_callid)
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{
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struct ip_conntrack_expect *exp_orig, *exp_reply;
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int ret = 1;
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typeof(ip_nat_pptp_hook_exp_gre) ip_nat_pptp_exp_gre;
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exp_orig = ip_conntrack_expect_alloc(ct);
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if (exp_orig == NULL)
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goto out;
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exp_reply = ip_conntrack_expect_alloc(ct);
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if (exp_reply == NULL)
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goto out_put_orig;
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/* original direction, PNS->PAC */
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exp_orig->tuple.src.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
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exp_orig->tuple.src.u.gre.key = peer_callid;
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exp_orig->tuple.dst.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip;
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exp_orig->tuple.dst.u.gre.key = callid;
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exp_orig->tuple.dst.protonum = IPPROTO_GRE;
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exp_orig->mask.src.ip = htonl(0xffffffff);
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exp_orig->mask.src.u.all = 0;
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exp_orig->mask.dst.u.gre.key = htons(0xffff);
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exp_orig->mask.dst.ip = htonl(0xffffffff);
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exp_orig->mask.dst.protonum = 0xff;
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exp_orig->master = ct;
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exp_orig->expectfn = pptp_expectfn;
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exp_orig->flags = 0;
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/* both expectations are identical apart from tuple */
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memcpy(exp_reply, exp_orig, sizeof(*exp_reply));
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/* reply direction, PAC->PNS */
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exp_reply->tuple.src.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip;
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exp_reply->tuple.src.u.gre.key = callid;
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exp_reply->tuple.dst.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
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exp_reply->tuple.dst.u.gre.key = peer_callid;
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exp_reply->tuple.dst.protonum = IPPROTO_GRE;
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ip_nat_pptp_exp_gre = rcu_dereference(ip_nat_pptp_hook_exp_gre);
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if (ip_nat_pptp_exp_gre)
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ip_nat_pptp_exp_gre(exp_orig, exp_reply);
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if (ip_conntrack_expect_related(exp_orig) != 0)
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goto out_put_both;
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if (ip_conntrack_expect_related(exp_reply) != 0)
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goto out_unexpect_orig;
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/* Add GRE keymap entries */
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if (ip_ct_gre_keymap_add(ct, &exp_orig->tuple, 0) != 0)
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goto out_unexpect_both;
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if (ip_ct_gre_keymap_add(ct, &exp_reply->tuple, 1) != 0) {
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ip_ct_gre_keymap_destroy(ct);
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goto out_unexpect_both;
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}
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ret = 0;
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out_put_both:
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ip_conntrack_expect_put(exp_reply);
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out_put_orig:
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ip_conntrack_expect_put(exp_orig);
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out:
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return ret;
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out_unexpect_both:
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ip_conntrack_unexpect_related(exp_reply);
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out_unexpect_orig:
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ip_conntrack_unexpect_related(exp_orig);
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goto out_put_both;
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}
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static inline int
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pptp_inbound_pkt(struct sk_buff **pskb,
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struct PptpControlHeader *ctlh,
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union pptp_ctrl_union *pptpReq,
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unsigned int reqlen,
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struct ip_conntrack *ct,
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enum ip_conntrack_info ctinfo)
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{
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struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info;
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u_int16_t msg;
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__be16 cid = 0, pcid = 0;
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typeof(ip_nat_pptp_hook_inbound) ip_nat_pptp_inbound;
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msg = ntohs(ctlh->messageType);
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DEBUGP("inbound control message %s\n", pptp_msg_name[msg]);
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switch (msg) {
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case PPTP_START_SESSION_REPLY:
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/* server confirms new control session */
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if (info->sstate < PPTP_SESSION_REQUESTED)
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goto invalid;
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if (pptpReq->srep.resultCode == PPTP_START_OK)
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info->sstate = PPTP_SESSION_CONFIRMED;
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else
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info->sstate = PPTP_SESSION_ERROR;
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break;
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case PPTP_STOP_SESSION_REPLY:
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/* server confirms end of control session */
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if (info->sstate > PPTP_SESSION_STOPREQ)
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goto invalid;
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if (pptpReq->strep.resultCode == PPTP_STOP_OK)
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info->sstate = PPTP_SESSION_NONE;
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else
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info->sstate = PPTP_SESSION_ERROR;
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break;
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case PPTP_OUT_CALL_REPLY:
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/* server accepted call, we now expect GRE frames */
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if (info->sstate != PPTP_SESSION_CONFIRMED)
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goto invalid;
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if (info->cstate != PPTP_CALL_OUT_REQ &&
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info->cstate != PPTP_CALL_OUT_CONF)
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goto invalid;
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cid = pptpReq->ocack.callID;
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pcid = pptpReq->ocack.peersCallID;
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if (info->pns_call_id != pcid)
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goto invalid;
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DEBUGP("%s, CID=%X, PCID=%X\n", pptp_msg_name[msg],
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ntohs(cid), ntohs(pcid));
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if (pptpReq->ocack.resultCode == PPTP_OUTCALL_CONNECT) {
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info->cstate = PPTP_CALL_OUT_CONF;
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info->pac_call_id = cid;
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exp_gre(ct, cid, pcid);
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} else
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info->cstate = PPTP_CALL_NONE;
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break;
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case PPTP_IN_CALL_REQUEST:
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/* server tells us about incoming call request */
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if (info->sstate != PPTP_SESSION_CONFIRMED)
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goto invalid;
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cid = pptpReq->icreq.callID;
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DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid));
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info->cstate = PPTP_CALL_IN_REQ;
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info->pac_call_id = cid;
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break;
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case PPTP_IN_CALL_CONNECT:
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/* server tells us about incoming call established */
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if (info->sstate != PPTP_SESSION_CONFIRMED)
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goto invalid;
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if (info->cstate != PPTP_CALL_IN_REP &&
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info->cstate != PPTP_CALL_IN_CONF)
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goto invalid;
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pcid = pptpReq->iccon.peersCallID;
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cid = info->pac_call_id;
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if (info->pns_call_id != pcid)
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goto invalid;
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DEBUGP("%s, PCID=%X\n", pptp_msg_name[msg], ntohs(pcid));
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info->cstate = PPTP_CALL_IN_CONF;
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/* we expect a GRE connection from PAC to PNS */
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exp_gre(ct, cid, pcid);
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break;
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case PPTP_CALL_DISCONNECT_NOTIFY:
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/* server confirms disconnect */
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cid = pptpReq->disc.callID;
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DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid));
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info->cstate = PPTP_CALL_NONE;
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/* untrack this call id, unexpect GRE packets */
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pptp_destroy_siblings(ct);
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break;
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case PPTP_WAN_ERROR_NOTIFY:
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case PPTP_ECHO_REQUEST:
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case PPTP_ECHO_REPLY:
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/* I don't have to explain these ;) */
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break;
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default:
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goto invalid;
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}
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ip_nat_pptp_inbound = rcu_dereference(ip_nat_pptp_hook_inbound);
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if (ip_nat_pptp_inbound)
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return ip_nat_pptp_inbound(pskb, ct, ctinfo, ctlh, pptpReq);
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return NF_ACCEPT;
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invalid:
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DEBUGP("invalid %s: type=%d cid=%u pcid=%u "
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"cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n",
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msg <= PPTP_MSG_MAX ? pptp_msg_name[msg] : pptp_msg_name[0],
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msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate,
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ntohs(info->pns_call_id), ntohs(info->pac_call_id));
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return NF_ACCEPT;
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}
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static inline int
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pptp_outbound_pkt(struct sk_buff **pskb,
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struct PptpControlHeader *ctlh,
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union pptp_ctrl_union *pptpReq,
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unsigned int reqlen,
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struct ip_conntrack *ct,
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enum ip_conntrack_info ctinfo)
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{
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struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info;
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u_int16_t msg;
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__be16 cid = 0, pcid = 0;
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typeof(ip_nat_pptp_hook_outbound) ip_nat_pptp_outbound;
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msg = ntohs(ctlh->messageType);
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DEBUGP("outbound control message %s\n", pptp_msg_name[msg]);
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switch (msg) {
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case PPTP_START_SESSION_REQUEST:
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/* client requests for new control session */
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if (info->sstate != PPTP_SESSION_NONE)
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goto invalid;
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info->sstate = PPTP_SESSION_REQUESTED;
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break;
|
|
case PPTP_STOP_SESSION_REQUEST:
|
|
/* client requests end of control session */
|
|
info->sstate = PPTP_SESSION_STOPREQ;
|
|
break;
|
|
|
|
case PPTP_OUT_CALL_REQUEST:
|
|
/* client initiating connection to server */
|
|
if (info->sstate != PPTP_SESSION_CONFIRMED)
|
|
goto invalid;
|
|
info->cstate = PPTP_CALL_OUT_REQ;
|
|
/* track PNS call id */
|
|
cid = pptpReq->ocreq.callID;
|
|
DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid));
|
|
info->pns_call_id = cid;
|
|
break;
|
|
case PPTP_IN_CALL_REPLY:
|
|
/* client answers incoming call */
|
|
if (info->cstate != PPTP_CALL_IN_REQ &&
|
|
info->cstate != PPTP_CALL_IN_REP)
|
|
goto invalid;
|
|
|
|
cid = pptpReq->icack.callID;
|
|
pcid = pptpReq->icack.peersCallID;
|
|
if (info->pac_call_id != pcid)
|
|
goto invalid;
|
|
DEBUGP("%s, CID=%X PCID=%X\n", pptp_msg_name[msg],
|
|
ntohs(cid), ntohs(pcid));
|
|
|
|
if (pptpReq->icack.resultCode == PPTP_INCALL_ACCEPT) {
|
|
/* part two of the three-way handshake */
|
|
info->cstate = PPTP_CALL_IN_REP;
|
|
info->pns_call_id = cid;
|
|
} else
|
|
info->cstate = PPTP_CALL_NONE;
|
|
break;
|
|
|
|
case PPTP_CALL_CLEAR_REQUEST:
|
|
/* client requests hangup of call */
|
|
if (info->sstate != PPTP_SESSION_CONFIRMED)
|
|
goto invalid;
|
|
/* FUTURE: iterate over all calls and check if
|
|
* call ID is valid. We don't do this without newnat,
|
|
* because we only know about last call */
|
|
info->cstate = PPTP_CALL_CLEAR_REQ;
|
|
break;
|
|
case PPTP_SET_LINK_INFO:
|
|
case PPTP_ECHO_REQUEST:
|
|
case PPTP_ECHO_REPLY:
|
|
/* I don't have to explain these ;) */
|
|
break;
|
|
default:
|
|
goto invalid;
|
|
}
|
|
|
|
ip_nat_pptp_outbound = rcu_dereference(ip_nat_pptp_hook_outbound);
|
|
if (ip_nat_pptp_outbound)
|
|
return ip_nat_pptp_outbound(pskb, ct, ctinfo, ctlh, pptpReq);
|
|
return NF_ACCEPT;
|
|
|
|
invalid:
|
|
DEBUGP("invalid %s: type=%d cid=%u pcid=%u "
|
|
"cstate=%d sstate=%d pns_cid=%u pac_cid=%u\n",
|
|
msg <= PPTP_MSG_MAX ? pptp_msg_name[msg] : pptp_msg_name[0],
|
|
msg, ntohs(cid), ntohs(pcid), info->cstate, info->sstate,
|
|
ntohs(info->pns_call_id), ntohs(info->pac_call_id));
|
|
return NF_ACCEPT;
|
|
}
|
|
|
|
static const unsigned int pptp_msg_size[] = {
|
|
[PPTP_START_SESSION_REQUEST] = sizeof(struct PptpStartSessionRequest),
|
|
[PPTP_START_SESSION_REPLY] = sizeof(struct PptpStartSessionReply),
|
|
[PPTP_STOP_SESSION_REQUEST] = sizeof(struct PptpStopSessionRequest),
|
|
[PPTP_STOP_SESSION_REPLY] = sizeof(struct PptpStopSessionReply),
|
|
[PPTP_OUT_CALL_REQUEST] = sizeof(struct PptpOutCallRequest),
|
|
[PPTP_OUT_CALL_REPLY] = sizeof(struct PptpOutCallReply),
|
|
[PPTP_IN_CALL_REQUEST] = sizeof(struct PptpInCallRequest),
|
|
[PPTP_IN_CALL_REPLY] = sizeof(struct PptpInCallReply),
|
|
[PPTP_IN_CALL_CONNECT] = sizeof(struct PptpInCallConnected),
|
|
[PPTP_CALL_CLEAR_REQUEST] = sizeof(struct PptpClearCallRequest),
|
|
[PPTP_CALL_DISCONNECT_NOTIFY] = sizeof(struct PptpCallDisconnectNotify),
|
|
[PPTP_WAN_ERROR_NOTIFY] = sizeof(struct PptpWanErrorNotify),
|
|
[PPTP_SET_LINK_INFO] = sizeof(struct PptpSetLinkInfo),
|
|
};
|
|
|
|
/* track caller id inside control connection, call expect_related */
|
|
static int
|
|
conntrack_pptp_help(struct sk_buff **pskb,
|
|
struct ip_conntrack *ct, enum ip_conntrack_info ctinfo)
|
|
|
|
{
|
|
int dir = CTINFO2DIR(ctinfo);
|
|
struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info;
|
|
struct tcphdr _tcph, *tcph;
|
|
struct pptp_pkt_hdr _pptph, *pptph;
|
|
struct PptpControlHeader _ctlh, *ctlh;
|
|
union pptp_ctrl_union _pptpReq, *pptpReq;
|
|
unsigned int tcplen = (*pskb)->len - (*pskb)->nh.iph->ihl * 4;
|
|
unsigned int datalen, reqlen, nexthdr_off;
|
|
int oldsstate, oldcstate;
|
|
int ret;
|
|
u_int16_t msg;
|
|
|
|
/* don't do any tracking before tcp handshake complete */
|
|
if (ctinfo != IP_CT_ESTABLISHED
|
|
&& ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY) {
|
|
DEBUGP("ctinfo = %u, skipping\n", ctinfo);
|
|
return NF_ACCEPT;
|
|
}
|
|
|
|
nexthdr_off = (*pskb)->nh.iph->ihl*4;
|
|
tcph = skb_header_pointer(*pskb, nexthdr_off, sizeof(_tcph), &_tcph);
|
|
BUG_ON(!tcph);
|
|
nexthdr_off += tcph->doff * 4;
|
|
datalen = tcplen - tcph->doff * 4;
|
|
|
|
pptph = skb_header_pointer(*pskb, nexthdr_off, sizeof(_pptph), &_pptph);
|
|
if (!pptph) {
|
|
DEBUGP("no full PPTP header, can't track\n");
|
|
return NF_ACCEPT;
|
|
}
|
|
nexthdr_off += sizeof(_pptph);
|
|
datalen -= sizeof(_pptph);
|
|
|
|
/* if it's not a control message we can't do anything with it */
|
|
if (ntohs(pptph->packetType) != PPTP_PACKET_CONTROL ||
|
|
ntohl(pptph->magicCookie) != PPTP_MAGIC_COOKIE) {
|
|
DEBUGP("not a control packet\n");
|
|
return NF_ACCEPT;
|
|
}
|
|
|
|
ctlh = skb_header_pointer(*pskb, nexthdr_off, sizeof(_ctlh), &_ctlh);
|
|
if (!ctlh)
|
|
return NF_ACCEPT;
|
|
nexthdr_off += sizeof(_ctlh);
|
|
datalen -= sizeof(_ctlh);
|
|
|
|
reqlen = datalen;
|
|
msg = ntohs(ctlh->messageType);
|
|
if (msg > 0 && msg <= PPTP_MSG_MAX && reqlen < pptp_msg_size[msg])
|
|
return NF_ACCEPT;
|
|
if (reqlen > sizeof(*pptpReq))
|
|
reqlen = sizeof(*pptpReq);
|
|
|
|
pptpReq = skb_header_pointer(*pskb, nexthdr_off, reqlen, &_pptpReq);
|
|
if (!pptpReq)
|
|
return NF_ACCEPT;
|
|
|
|
oldsstate = info->sstate;
|
|
oldcstate = info->cstate;
|
|
|
|
spin_lock_bh(&ip_pptp_lock);
|
|
|
|
/* FIXME: We just blindly assume that the control connection is always
|
|
* established from PNS->PAC. However, RFC makes no guarantee */
|
|
if (dir == IP_CT_DIR_ORIGINAL)
|
|
/* client -> server (PNS -> PAC) */
|
|
ret = pptp_outbound_pkt(pskb, ctlh, pptpReq, reqlen, ct,
|
|
ctinfo);
|
|
else
|
|
/* server -> client (PAC -> PNS) */
|
|
ret = pptp_inbound_pkt(pskb, ctlh, pptpReq, reqlen, ct,
|
|
ctinfo);
|
|
DEBUGP("sstate: %d->%d, cstate: %d->%d\n",
|
|
oldsstate, info->sstate, oldcstate, info->cstate);
|
|
spin_unlock_bh(&ip_pptp_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* control protocol helper */
|
|
static struct ip_conntrack_helper pptp = {
|
|
.list = { NULL, NULL },
|
|
.name = "pptp",
|
|
.me = THIS_MODULE,
|
|
.max_expected = 2,
|
|
.timeout = 5 * 60,
|
|
.tuple = { .src = { .ip = 0,
|
|
.u = { .tcp = { .port =
|
|
__constant_htons(PPTP_CONTROL_PORT) } }
|
|
},
|
|
.dst = { .ip = 0,
|
|
.u = { .all = 0 },
|
|
.protonum = IPPROTO_TCP
|
|
}
|
|
},
|
|
.mask = { .src = { .ip = 0,
|
|
.u = { .tcp = { .port = __constant_htons(0xffff) } }
|
|
},
|
|
.dst = { .ip = 0,
|
|
.u = { .all = 0 },
|
|
.protonum = 0xff
|
|
}
|
|
},
|
|
.help = conntrack_pptp_help,
|
|
.destroy = pptp_destroy_siblings,
|
|
};
|
|
|
|
extern void ip_ct_proto_gre_fini(void);
|
|
extern int __init ip_ct_proto_gre_init(void);
|
|
|
|
/* ip_conntrack_pptp initialization */
|
|
static int __init ip_conntrack_helper_pptp_init(void)
|
|
{
|
|
int retcode;
|
|
|
|
retcode = ip_ct_proto_gre_init();
|
|
if (retcode < 0)
|
|
return retcode;
|
|
|
|
DEBUGP(" registering helper\n");
|
|
if ((retcode = ip_conntrack_helper_register(&pptp))) {
|
|
printk(KERN_ERR "Unable to register conntrack application "
|
|
"helper for pptp: %d\n", retcode);
|
|
ip_ct_proto_gre_fini();
|
|
return retcode;
|
|
}
|
|
|
|
printk("ip_conntrack_pptp version %s loaded\n", IP_CT_PPTP_VERSION);
|
|
return 0;
|
|
}
|
|
|
|
static void __exit ip_conntrack_helper_pptp_fini(void)
|
|
{
|
|
ip_conntrack_helper_unregister(&pptp);
|
|
ip_ct_proto_gre_fini();
|
|
printk("ip_conntrack_pptp version %s unloaded\n", IP_CT_PPTP_VERSION);
|
|
}
|
|
|
|
module_init(ip_conntrack_helper_pptp_init);
|
|
module_exit(ip_conntrack_helper_pptp_fini);
|
|
|
|
EXPORT_SYMBOL(ip_nat_pptp_hook_outbound);
|
|
EXPORT_SYMBOL(ip_nat_pptp_hook_inbound);
|
|
EXPORT_SYMBOL(ip_nat_pptp_hook_exp_gre);
|
|
EXPORT_SYMBOL(ip_nat_pptp_hook_expectfn);
|