[NETFILTER]: nf_conntrack/nf_nat: add PPTP helper port
Add nf_conntrack port of the PPtP conntrack/NAT helper. Since there seems
to be no IPv6-capable PPtP implementation the helper only support IPv4.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index d1a365d..6b2eb26 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -120,6 +120,10 @@
If unsure, say `N'.
+config NF_CT_PROTO_GRE
+ tristate
+ depends on EXPERIMENTAL && NF_CONNTRACK
+
config NF_CT_PROTO_SCTP
tristate 'SCTP protocol on new connection tracking support (EXPERIMENTAL)'
depends on EXPERIMENTAL && NF_CONNTRACK
@@ -213,6 +217,25 @@
To compile it as a module, choose M here. If unsure, say N.
+config NF_CONNTRACK_PPTP
+ tristate "PPtP protocol support (EXPERIMENTAL)"
+ depends on EXPERIMENTAL && NF_CONNTRACK
+ select NF_CT_PROTO_GRE
+ help
+ This module adds support for PPTP (Point to Point Tunnelling
+ Protocol, RFC2637) connection tracking and NAT.
+
+ If you are running PPTP sessions over a stateful firewall or NAT
+ box, you may want to enable this feature.
+
+ Please note that not all PPTP modes of operation are supported yet.
+ Specifically these limitations exist:
+ - Blindy assumes that control connections are always established
+ in PNS->PAC direction. This is a violation of RFC2637.
+ - Only supports a single call within each session
+
+ To compile it as a module, choose M here. If unsure, say N.
+
config NF_CT_NETLINK
tristate 'Connection tracking netlink interface (EXPERIMENTAL)'
depends on EXPERIMENTAL && NF_CONNTRACK && NETFILTER_NETLINK
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 67144b2..897bed4 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -14,6 +14,7 @@
obj-$(CONFIG_NF_CONNTRACK) += nf_conntrack.o
# SCTP protocol connection tracking
+obj-$(CONFIG_NF_CT_PROTO_GRE) += nf_conntrack_proto_gre.o
obj-$(CONFIG_NF_CT_PROTO_SCTP) += nf_conntrack_proto_sctp.o
# netlink interface for nf_conntrack
@@ -27,6 +28,7 @@
obj-$(CONFIG_NF_CONNTRACK_H323) += nf_conntrack_h323.o
obj-$(CONFIG_NF_CONNTRACK_IRC) += nf_conntrack_irc.o
obj-$(CONFIG_NF_CONNTRACK_NETBIOS_NS) += nf_conntrack_netbios_ns.o
+obj-$(CONFIG_NF_CONNTRACK_PPTP) += nf_conntrack_pptp.o
# generic X tables
obj-$(CONFIG_NETFILTER_XTABLES) += x_tables.o xt_tcpudp.o
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index aa8beab..ed756c9 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -300,6 +300,7 @@
destroy_conntrack(struct nf_conntrack *nfct)
{
struct nf_conn *ct = (struct nf_conn *)nfct;
+ struct nf_conn_help *help = nfct_help(ct);
struct nf_conntrack_l3proto *l3proto;
struct nf_conntrack_l4proto *l4proto;
@@ -310,6 +311,9 @@
nf_conntrack_event(IPCT_DESTROY, ct);
set_bit(IPS_DYING_BIT, &ct->status);
+ if (help && help->helper && help->helper->destroy)
+ help->helper->destroy(ct);
+
/* To make sure we don't get any weird locking issues here:
* destroy_conntrack() MUST NOT be called with a write lock
* to nf_conntrack_lock!!! -HW */
diff --git a/net/netfilter/nf_conntrack_pptp.c b/net/netfilter/nf_conntrack_pptp.c
new file mode 100644
index 0000000..f0ff00e
--- /dev/null
+++ b/net/netfilter/nf_conntrack_pptp.c
@@ -0,0 +1,607 @@
+/*
+ * Connection tracking support for PPTP (Point to Point Tunneling Protocol).
+ * PPTP is a a protocol for creating virtual private networks.
+ * It is a specification defined by Microsoft and some vendors
+ * working with Microsoft. PPTP is built on top of a modified
+ * version of the Internet Generic Routing Encapsulation Protocol.
+ * GRE is defined in RFC 1701 and RFC 1702. Documentation of
+ * 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/)
+ *
+ * Limitations:
+ * - We blindly assume that control connections are always
+ * established in PNS->PAC direction. This is a violation
+ * of RFFC2673
+ * - We can only support one single call within each session
+ * TODO:
+ * - testing of incoming PPTP calls
+ */
+
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/in.h>
+#include <linux/tcp.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <linux/netfilter/nf_conntrack_proto_gre.h>
+#include <linux/netfilter/nf_conntrack_pptp.h>
+
+#define NF_CT_PPTP_VERSION "3.1"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
+MODULE_DESCRIPTION("Netfilter connection tracking helper module for PPTP");
+MODULE_ALIAS("ip_conntrack_pptp");
+
+static DEFINE_SPINLOCK(nf_pptp_lock);
+
+int
+(*nf_nat_pptp_hook_outbound)(struct sk_buff **pskb,
+ struct nf_conn *ct, enum ip_conntrack_info ctinfo,
+ struct PptpControlHeader *ctlh,
+ union pptp_ctrl_union *pptpReq) __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_outbound);
+
+int
+(*nf_nat_pptp_hook_inbound)(struct sk_buff **pskb,
+ struct nf_conn *ct, enum ip_conntrack_info ctinfo,
+ struct PptpControlHeader *ctlh,
+ union pptp_ctrl_union *pptpReq) __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_inbound);
+
+void
+(*nf_nat_pptp_hook_exp_gre)(struct nf_conntrack_expect *expect_orig,
+ struct nf_conntrack_expect *expect_reply)
+ __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_exp_gre);
+
+void
+(*nf_nat_pptp_hook_expectfn)(struct nf_conn *ct,
+ struct nf_conntrack_expect *exp) __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_pptp_hook_expectfn);
+
+#if 0
+/* PptpControlMessageType names */
+const char *pptp_msg_name[] = {
+ "UNKNOWN_MESSAGE",
+ "START_SESSION_REQUEST",
+ "START_SESSION_REPLY",
+ "STOP_SESSION_REQUEST",
+ "STOP_SESSION_REPLY",
+ "ECHO_REQUEST",
+ "ECHO_REPLY",
+ "OUT_CALL_REQUEST",
+ "OUT_CALL_REPLY",
+ "IN_CALL_REQUEST",
+ "IN_CALL_REPLY",
+ "IN_CALL_CONNECT",
+ "CALL_CLEAR_REQUEST",
+ "CALL_DISCONNECT_NOTIFY",
+ "WAN_ERROR_NOTIFY",
+ "SET_LINK_INFO"
+};
+EXPORT_SYMBOL(pptp_msg_name);
+#define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s: " format, __FILE__, __FUNCTION__, ## args)
+#else
+#define DEBUGP(format, args...)
+#endif
+
+#define SECS *HZ
+#define MINS * 60 SECS
+#define HOURS * 60 MINS
+
+#define PPTP_GRE_TIMEOUT (10 MINS)
+#define PPTP_GRE_STREAM_TIMEOUT (5 HOURS)
+
+static void pptp_expectfn(struct nf_conn *ct,
+ struct nf_conntrack_expect *exp)
+{
+ typeof(nf_nat_pptp_hook_expectfn) nf_nat_pptp_expectfn;
+ DEBUGP("increasing timeouts\n");
+
+ /* increase timeout of GRE data channel conntrack entry */
+ ct->proto.gre.timeout = PPTP_GRE_TIMEOUT;
+ ct->proto.gre.stream_timeout = PPTP_GRE_STREAM_TIMEOUT;
+
+ /* Can you see how rusty this code is, compared with the pre-2.6.11
+ * one? That's what happened to my shiny newnat of 2002 ;( -HW */
+
+ rcu_read_lock();
+ nf_nat_pptp_expectfn = rcu_dereference(nf_nat_pptp_hook_expectfn);
+ if (nf_nat_pptp_expectfn && ct->status & IPS_NAT_MASK)
+ nf_nat_pptp_expectfn(ct, exp);
+ else {
+ struct nf_conntrack_tuple inv_t;
+ struct nf_conntrack_expect *exp_other;
+
+ /* obviously this tuple inversion only works until you do NAT */
+ nf_ct_invert_tuplepr(&inv_t, &exp->tuple);
+ DEBUGP("trying to unexpect other dir: ");
+ NF_CT_DUMP_TUPLE(&inv_t);
+
+ exp_other = nf_conntrack_expect_find_get(&inv_t);
+ if (exp_other) {
+ /* delete other expectation. */
+ DEBUGP("found\n");
+ nf_conntrack_unexpect_related(exp_other);
+ nf_conntrack_expect_put(exp_other);
+ } else {
+ DEBUGP("not found\n");
+ }
+ }
+ rcu_read_unlock();
+}
+
+static int destroy_sibling_or_exp(const struct nf_conntrack_tuple *t)
+{
+ struct nf_conntrack_tuple_hash *h;
+ struct nf_conntrack_expect *exp;
+ struct nf_conn *sibling;
+
+ DEBUGP("trying to timeout ct or exp for tuple ");
+ NF_CT_DUMP_TUPLE(t);
+
+ h = nf_conntrack_find_get(t, NULL);
+ if (h) {
+ sibling = nf_ct_tuplehash_to_ctrack(h);
+ DEBUGP("setting timeout of conntrack %p to 0\n", sibling);
+ sibling->proto.gre.timeout = 0;
+ sibling->proto.gre.stream_timeout = 0;
+ if (del_timer(&sibling->timeout))
+ sibling->timeout.function((unsigned long)sibling);
+ nf_ct_put(sibling);
+ return 1;
+ } else {
+ exp = nf_conntrack_expect_find_get(t);
+ if (exp) {
+ DEBUGP("unexpect_related of expect %p\n", exp);
+ nf_conntrack_unexpect_related(exp);
+ nf_conntrack_expect_put(exp);
+ return 1;
+ }
+ }
+ return 0;
+}
+
+/* timeout GRE data connections */
+static void pptp_destroy_siblings(struct nf_conn *ct)
+{
+ struct nf_conn_help *help = nfct_help(ct);
+ struct nf_conntrack_tuple t;
+
+ nf_ct_gre_keymap_destroy(ct);
+
+ /* try original (pns->pac) tuple */
+ memcpy(&t, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, sizeof(t));
+ t.dst.protonum = IPPROTO_GRE;
+ t.src.u.gre.key = help->help.ct_pptp_info.pns_call_id;
+ t.dst.u.gre.key = help->help.ct_pptp_info.pac_call_id;
+ if (!destroy_sibling_or_exp(&t))
+ DEBUGP("failed to timeout original pns->pac ct/exp\n");
+
+ /* try reply (pac->pns) tuple */
+ memcpy(&t, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, sizeof(t));
+ t.dst.protonum = IPPROTO_GRE;
+ t.src.u.gre.key = help->help.ct_pptp_info.pac_call_id;
+ t.dst.u.gre.key = help->help.ct_pptp_info.pns_call_id;
+ if (!destroy_sibling_or_exp(&t))
+ DEBUGP("failed to timeout reply pac->pns ct/exp\n");
+}
+
+/* expect GRE connections (PNS->PAC and PAC->PNS direction) */
+static int exp_gre(struct nf_conn *ct, __be16 callid, __be16 peer_callid)
+{
+ struct nf_conntrack_expect *exp_orig, *exp_reply;
+ enum ip_conntrack_dir dir;
+ int ret = 1;
+ typeof(nf_nat_pptp_hook_exp_gre) nf_nat_pptp_exp_gre;
+
+ exp_orig = nf_conntrack_expect_alloc(ct);
+ if (exp_orig == NULL)
+ goto out;
+
+ exp_reply = nf_conntrack_expect_alloc(ct);
+ if (exp_reply == NULL)
+ goto out_put_orig;
+
+ /* original direction, PNS->PAC */
+ dir = IP_CT_DIR_ORIGINAL;
+ nf_conntrack_expect_init(exp_orig, ct->tuplehash[dir].tuple.src.l3num,
+ &ct->tuplehash[dir].tuple.src.u3,
+ &ct->tuplehash[dir].tuple.dst.u3,
+ IPPROTO_GRE, &peer_callid, &callid);
+ exp_orig->expectfn = pptp_expectfn;
+
+ /* reply direction, PAC->PNS */
+ dir = IP_CT_DIR_REPLY;
+ nf_conntrack_expect_init(exp_reply, ct->tuplehash[dir].tuple.src.l3num,
+ &ct->tuplehash[dir].tuple.src.u3,
+ &ct->tuplehash[dir].tuple.dst.u3,
+ IPPROTO_GRE, &callid, &peer_callid);
+ exp_reply->expectfn = pptp_expectfn;
+
+ nf_nat_pptp_exp_gre = rcu_dereference(nf_nat_pptp_hook_exp_gre);
+ if (nf_nat_pptp_exp_gre && ct->status & IPS_NAT_MASK)
+ nf_nat_pptp_exp_gre(exp_orig, exp_reply);
+ if (nf_conntrack_expect_related(exp_orig) != 0)
+ goto out_put_both;
+ if (nf_conntrack_expect_related(exp_reply) != 0)
+ goto out_unexpect_orig;
+
+ /* Add GRE keymap entries */
+ if (nf_ct_gre_keymap_add(ct, IP_CT_DIR_ORIGINAL, &exp_orig->tuple) != 0)
+ goto out_unexpect_both;
+ if (nf_ct_gre_keymap_add(ct, IP_CT_DIR_REPLY, &exp_reply->tuple) != 0) {
+ nf_ct_gre_keymap_destroy(ct);
+ goto out_unexpect_both;
+ }
+ ret = 0;
+
+out_put_both:
+ nf_conntrack_expect_put(exp_reply);
+out_put_orig:
+ nf_conntrack_expect_put(exp_orig);
+out:
+ return ret;
+
+out_unexpect_both:
+ nf_conntrack_unexpect_related(exp_reply);
+out_unexpect_orig:
+ nf_conntrack_unexpect_related(exp_orig);
+ goto out_put_both;
+}
+
+static inline int
+pptp_inbound_pkt(struct sk_buff **pskb,
+ struct PptpControlHeader *ctlh,
+ union pptp_ctrl_union *pptpReq,
+ unsigned int reqlen,
+ struct nf_conn *ct,
+ enum ip_conntrack_info ctinfo)
+{
+ struct nf_ct_pptp_master *info = &nfct_help(ct)->help.ct_pptp_info;
+ u_int16_t msg;
+ __be16 cid = 0, pcid = 0;
+ typeof(nf_nat_pptp_hook_inbound) nf_nat_pptp_inbound;
+
+ msg = ntohs(ctlh->messageType);
+ DEBUGP("inbound control message %s\n", pptp_msg_name[msg]);
+
+ switch (msg) {
+ case PPTP_START_SESSION_REPLY:
+ /* server confirms new control session */
+ if (info->sstate < PPTP_SESSION_REQUESTED)
+ goto invalid;
+ if (pptpReq->srep.resultCode == PPTP_START_OK)
+ info->sstate = PPTP_SESSION_CONFIRMED;
+ else
+ info->sstate = PPTP_SESSION_ERROR;
+ break;
+
+ case PPTP_STOP_SESSION_REPLY:
+ /* server confirms end of control session */
+ if (info->sstate > PPTP_SESSION_STOPREQ)
+ goto invalid;
+ if (pptpReq->strep.resultCode == PPTP_STOP_OK)
+ info->sstate = PPTP_SESSION_NONE;
+ else
+ info->sstate = PPTP_SESSION_ERROR;
+ break;
+
+ case PPTP_OUT_CALL_REPLY:
+ /* server accepted call, we now expect GRE frames */
+ if (info->sstate != PPTP_SESSION_CONFIRMED)
+ goto invalid;
+ if (info->cstate != PPTP_CALL_OUT_REQ &&
+ info->cstate != PPTP_CALL_OUT_CONF)
+ goto invalid;
+
+ cid = pptpReq->ocack.callID;
+ pcid = pptpReq->ocack.peersCallID;
+ if (info->pns_call_id != pcid)
+ goto invalid;
+ DEBUGP("%s, CID=%X, PCID=%X\n", pptp_msg_name[msg],
+ ntohs(cid), ntohs(pcid));
+
+ if (pptpReq->ocack.resultCode == PPTP_OUTCALL_CONNECT) {
+ info->cstate = PPTP_CALL_OUT_CONF;
+ info->pac_call_id = cid;
+ exp_gre(ct, cid, pcid);
+ } else
+ info->cstate = PPTP_CALL_NONE;
+ break;
+
+ case PPTP_IN_CALL_REQUEST:
+ /* server tells us about incoming call request */
+ if (info->sstate != PPTP_SESSION_CONFIRMED)
+ goto invalid;
+
+ cid = pptpReq->icreq.callID;
+ DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid));
+ info->cstate = PPTP_CALL_IN_REQ;
+ info->pac_call_id = cid;
+ break;
+
+ case PPTP_IN_CALL_CONNECT:
+ /* server tells us about incoming call established */
+ if (info->sstate != PPTP_SESSION_CONFIRMED)
+ goto invalid;
+ if (info->cstate != PPTP_CALL_IN_REP &&
+ info->cstate != PPTP_CALL_IN_CONF)
+ goto invalid;
+
+ pcid = pptpReq->iccon.peersCallID;
+ cid = info->pac_call_id;
+
+ if (info->pns_call_id != pcid)
+ goto invalid;
+
+ DEBUGP("%s, PCID=%X\n", pptp_msg_name[msg], ntohs(pcid));
+ info->cstate = PPTP_CALL_IN_CONF;
+
+ /* we expect a GRE connection from PAC to PNS */
+ exp_gre(ct, cid, pcid);
+ break;
+
+ case PPTP_CALL_DISCONNECT_NOTIFY:
+ /* server confirms disconnect */
+ cid = pptpReq->disc.callID;
+ DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(cid));
+ info->cstate = PPTP_CALL_NONE;
+
+ /* untrack this call id, unexpect GRE packets */
+ pptp_destroy_siblings(ct);
+ break;
+
+ case PPTP_WAN_ERROR_NOTIFY:
+ case PPTP_ECHO_REQUEST:
+ case PPTP_ECHO_REPLY:
+ /* I don't have to explain these ;) */
+ break;
+
+ default:
+ goto invalid;
+ }
+
+ nf_nat_pptp_inbound = rcu_dereference(nf_nat_pptp_hook_inbound);
+ if (nf_nat_pptp_inbound && ct->status & IPS_NAT_MASK)
+ return nf_nat_pptp_inbound(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 inline int
+pptp_outbound_pkt(struct sk_buff **pskb,
+ struct PptpControlHeader *ctlh,
+ union pptp_ctrl_union *pptpReq,
+ unsigned int reqlen,
+ struct nf_conn *ct,
+ enum ip_conntrack_info ctinfo)
+{
+ struct nf_ct_pptp_master *info = &nfct_help(ct)->help.ct_pptp_info;
+ u_int16_t msg;
+ __be16 cid = 0, pcid = 0;
+ typeof(nf_nat_pptp_hook_outbound) nf_nat_pptp_outbound;
+
+ msg = ntohs(ctlh->messageType);
+ DEBUGP("outbound control message %s\n", pptp_msg_name[msg]);
+
+ switch (msg) {
+ case PPTP_START_SESSION_REQUEST:
+ /* client requests for new control session */
+ if (info->sstate != PPTP_SESSION_NONE)
+ goto invalid;
+ info->sstate = PPTP_SESSION_REQUESTED;
+ 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;
+ }
+
+ nf_nat_pptp_outbound = rcu_dereference(nf_nat_pptp_hook_outbound);
+ if (nf_nat_pptp_outbound && ct->status & IPS_NAT_MASK)
+ return nf_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, unsigned int protoff,
+ struct nf_conn *ct, enum ip_conntrack_info ctinfo)
+
+{
+ int dir = CTINFO2DIR(ctinfo);
+ struct nf_ct_pptp_master *info = &nfct_help(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 - protoff;
+ 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)
+ return NF_ACCEPT;
+
+ nexthdr_off = protoff;
+ 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(&nf_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(&nf_pptp_lock);
+
+ return ret;
+}
+
+/* control protocol helper */
+static struct nf_conntrack_helper pptp __read_mostly = {
+ .name = "pptp",
+ .me = THIS_MODULE,
+ .max_expected = 2,
+ .timeout = 5 * 60,
+ .tuple.src.l3num = AF_INET,
+ .tuple.src.u.tcp.port = __constant_htons(PPTP_CONTROL_PORT),
+ .tuple.dst.protonum = IPPROTO_TCP,
+ .mask.src.l3num = 0xffff,
+ .mask.src.u.tcp.port = __constant_htons(0xffff),
+ .mask.dst.protonum = 0xff,
+ .help = conntrack_pptp_help,
+ .destroy = pptp_destroy_siblings,
+};
+
+static int __init nf_conntrack_pptp_init(void)
+{
+ return nf_conntrack_helper_register(&pptp);
+}
+
+static void __exit nf_conntrack_pptp_fini(void)
+{
+ nf_conntrack_helper_unregister(&pptp);
+ nf_ct_gre_keymap_flush();
+}
+
+module_init(nf_conntrack_pptp_init);
+module_exit(nf_conntrack_pptp_fini);
diff --git a/net/netfilter/nf_conntrack_proto_gre.c b/net/netfilter/nf_conntrack_proto_gre.c
new file mode 100644
index 0000000..ac193ce
--- /dev/null
+++ b/net/netfilter/nf_conntrack_proto_gre.c
@@ -0,0 +1,305 @@
+/*
+ * 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/list.h>
+#include <linux/seq_file.h>
+#include <linux/in.h>
+#include <linux/skbuff.h>
+
+#include <net/netfilter/nf_conntrack_l4proto.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <linux/netfilter/nf_conntrack_proto_gre.h>
+#include <linux/netfilter/nf_conntrack_pptp.h>
+
+#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)
+#else
+#define DEBUGP(x, args...)
+#endif
+
+static DEFINE_RWLOCK(nf_ct_gre_lock);
+static LIST_HEAD(gre_keymap_list);
+
+void nf_ct_gre_keymap_flush(void)
+{
+ struct list_head *pos, *n;
+
+ write_lock_bh(&nf_ct_gre_lock);
+ list_for_each_safe(pos, n, &gre_keymap_list) {
+ list_del(pos);
+ kfree(pos);
+ }
+ write_unlock_bh(&nf_ct_gre_lock);
+}
+EXPORT_SYMBOL(nf_ct_gre_keymap_flush);
+
+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 nf_conntrack_tuple *t)
+{
+ struct nf_ct_gre_keymap *km;
+ __be16 key = 0;
+
+ read_lock_bh(&nf_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(&nf_ct_gre_lock);
+
+ DEBUGP("lookup src key 0x%x for ", key);
+ NF_CT_DUMP_TUPLE(t);
+
+ return key;
+}
+
+/* add a single keymap entry, associate with specified master ct */
+int nf_ct_gre_keymap_add(struct nf_conn *ct, enum ip_conntrack_dir dir,
+ struct nf_conntrack_tuple *t)
+{
+ struct nf_conn_help *help = nfct_help(ct);
+ struct nf_ct_gre_keymap **kmp, *km;
+
+ BUG_ON(strcmp(help->helper->name, "pptp"));
+ kmp = &help->help.ct_pptp_info.keymap[dir];
+ if (*kmp) {
+ /* check whether it's a retransmission */
+ list_for_each_entry(km, &gre_keymap_list, list) {
+ if (gre_key_cmpfn(km, t) && km == *kmp)
+ return 0;
+ }
+ DEBUGP("trying to override keymap_%s for ct %p\n",
+ dir == IP_CT_DIR_REPLY ? "reply" : "orig", ct);
+ return -EEXIST;
+ }
+
+ km = kmalloc(sizeof(*km), GFP_ATOMIC);
+ if (!km)
+ return -ENOMEM;
+ memcpy(&km->tuple, t, sizeof(*t));
+ *kmp = km;
+
+ DEBUGP("adding new entry %p: ", km);
+ NF_CT_DUMP_TUPLE(&km->tuple);
+
+ write_lock_bh(&nf_ct_gre_lock);
+ list_add_tail(&km->list, &gre_keymap_list);
+ write_unlock_bh(&nf_ct_gre_lock);
+
+ return 0;
+}
+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_conn_help *help = nfct_help(ct);
+ enum ip_conntrack_dir dir;
+
+ DEBUGP("entering for ct %p\n", ct);
+ BUG_ON(strcmp(help->helper->name, "pptp"));
+
+ write_lock_bh(&nf_ct_gre_lock);
+ for (dir = IP_CT_DIR_ORIGINAL; dir < IP_CT_DIR_MAX; dir++) {
+ if (help->help.ct_pptp_info.keymap[dir]) {
+ DEBUGP("removing %p from list\n",
+ help->help.ct_pptp_info.keymap[dir]);
+ list_del(&help->help.ct_pptp_info.keymap[dir]->list);
+ kfree(help->help.ct_pptp_info.keymap[dir]);
+ help->help.ct_pptp_info.keymap[dir] = NULL;
+ }
+ }
+ write_unlock_bh(&nf_ct_gre_lock);
+}
+EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_destroy);
+
+/* PUBLIC CONNTRACK PROTO HELPER FUNCTIONS */
+
+/* invert gre part of tuple */
+static int gre_invert_tuple(struct nf_conntrack_tuple *tuple,
+ const struct nf_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 nf_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 "nf_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 nf_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 nf_conn *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 nf_conn *ct,
+ const struct sk_buff *skb,
+ unsigned int dataoff,
+ enum ip_conntrack_info ctinfo,
+ int pf,
+ unsigned int hooknum)
+{
+ /* If we've seen traffic both ways, this is a GRE connection.
+ * Extend timeout. */
+ if (ct->status & IPS_SEEN_REPLY) {
+ nf_ct_refresh_acct(ct, ctinfo, skb,
+ ct->proto.gre.stream_timeout);
+ /* Also, more likely to be important, and not a probe. */
+ set_bit(IPS_ASSURED_BIT, &ct->status);
+ nf_conntrack_event_cache(IPCT_STATUS, skb);
+ } else
+ nf_ct_refresh_acct(ct, ctinfo, skb,
+ ct->proto.gre.timeout);
+
+ return NF_ACCEPT;
+}
+
+/* Called when a new connection for this protocol found. */
+static int gre_new(struct nf_conn *ct, const struct sk_buff *skb,
+ unsigned int dataoff)
+{
+ DEBUGP(": ");
+ NF_CT_DUMP_TUPLE(&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 nf_conn *ct)
+{
+ struct nf_conn *master = ct->master;
+ DEBUGP(" entering\n");
+
+ if (!master)
+ DEBUGP("no master !?!\n");
+ else
+ nf_ct_gre_keymap_destroy(master);
+}
+
+/* protocol helper struct */
+static struct nf_conntrack_l4proto nf_conntrack_l4proto_gre4 = {
+ .l3proto = AF_INET,
+ .l4proto = 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_NF_CONNTRACK_NETLINK) || \
+ defined(CONFIG_NF_CONNTRACK_NETLINK_MODULE)
+ .tuple_to_nfattr = nf_ct_port_tuple_to_nfattr,
+ .nfattr_to_tuple = nf_ct_port_nfattr_to_tuple,
+#endif
+};
+
+static int __init nf_ct_proto_gre_init(void)
+{
+ return nf_conntrack_l4proto_register(&nf_conntrack_l4proto_gre4);
+}
+
+static void nf_ct_proto_gre_fini(void)
+{
+ nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_gre4);
+ nf_ct_gre_keymap_flush();
+}
+
+module_init(nf_ct_proto_gre_init);
+module_exit(nf_ct_proto_gre_fini);
+
+MODULE_LICENSE("GPL");
