imported original firmware WRT54GL_v4.30.11_11_US

1 files changed, 466 insertions, 0 deletions

diff --git a/release/src/linux/linux/net/ipv4/netfilter/ip_nat_pptp.c b/release/src/linux/linux/net/ipv4/netfilter/ip_nat_pptp.c
new file mode 100644
index 00000000..71077933
--- /dev/null
+++ b/release/src/linux/linux/net/ipv4/netfilter/ip_nat_pptp.c
@@ -0,0 +1,466 @@
+/*
+ * ip_nat_pptp.c	- Version 1.11
+ *
+ * NAT 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) 2000-2002 by Harald Welte <laforge@gnumonks.org>
+ *
+ * Development of this code funded by Astaro AG (http://www.astaro.com/)
+ *
+ * TODO: - Support for multiple calls within one session
+ * 	   (needs netfilter newnat code)
+ * 	 - NAT to a unique tuple, not to TCP source port
+ * 	   (needs netfilter tuple reservation)
+ * 	 - Support other NAT scenarios than SNAT of PNS
+ * 
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/ip.h>
+#include <linux/tcp.h>
+#include <net/tcp.h>
+#include <linux/netfilter_ipv4/ip_nat.h>
+#include <linux/netfilter_ipv4/ip_nat_rule.h>
+#include <linux/netfilter_ipv4/ip_nat_helper.h>
+#include <linux/netfilter_ipv4/ip_nat_pptp.h>
+#include <linux/netfilter_ipv4/ip_conntrack_helper.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 NAT helper module for PPTP");
+
+
+#if 0
+#include "ip_conntrack_pptp_priv.h"
+#define DEBUGP(format, args...) printk(KERN_DEBUG __FILE__ ":" __FUNCTION__ \
+				       ": " format, ## args)
+#else
+#define DEBUGP(format, args...)
+#endif
+
+static unsigned int
+pptp_nat_expected(struct sk_buff **pskb,
+		  unsigned int hooknum,
+		  struct ip_conntrack *ct,
+		  struct ip_nat_info *info)
+{
+	struct ip_conntrack *master = master_ct(ct);
+	struct ip_nat_multi_range mr;
+	struct ip_ct_pptp_master *ct_pptp_info;
+	struct ip_nat_pptp *nat_pptp_info;
+	u_int32_t newsrcip, newdstip, newcid;
+	int ret;
+
+	IP_NF_ASSERT(info);
+	IP_NF_ASSERT(master);
+	IP_NF_ASSERT(!(info->initialized & (1 << HOOK2MANIP(hooknum))));
+
+	DEBUGP("we have a connection!\n");
+
+	LOCK_BH(&ip_pptp_lock);
+	ct_pptp_info = &master->help.ct_pptp_info;
+	nat_pptp_info = &master->nat.help.nat_pptp_info;
+
+	/* need to alter GRE tuple because conntrack expectfn() used 'wrong'
+	 * (unmanipulated) values */
+	if (hooknum == NF_IP_PRE_ROUTING) {
+		DEBUGP("completing tuples with NAT info \n");
+		/* we can do this, since we're unconfirmed */
+		if (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.gre.key ==
+			htonl(ct_pptp_info->pac_call_id)) {	
+			/* assume PNS->PAC */
+			ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.gre.key =
+				htonl(nat_pptp_info->pns_call_id);
+//			ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u.gre.key =
+//				htonl(nat_pptp_info->pac_call_id);
+			ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u.gre.key =
+				htonl(nat_pptp_info->pns_call_id);
+		} else {
+			/* assume PAC->PNS */
+			DEBUGP("WRONG DIRECTION\n");
+			ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.gre.key =
+				htonl(nat_pptp_info->pac_call_id);
+			ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u.gre.key =
+				htonl(nat_pptp_info->pac_call_id);
+		}
+	}
+
+	if (HOOK2MANIP(hooknum) == IP_NAT_MANIP_DST)
+	{
+		if (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.gre.key == htonl(ct_pptp_info->pac_call_id))
+		{
+			/* assume PNS->PAC */
+			newdstip = master->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip;
+			newcid = htonl(nat_pptp_info->pac_call_id);
+		}
+		else
+		{
+			/* assume PAC->PNS */
+			newdstip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
+			newcid = htonl(nat_pptp_info->pns_call_id);
+		}
+		mr.rangesize = 1;
+		mr.range[0].flags = IP_NAT_RANGE_MAP_IPS | IP_NAT_RANGE_PROTO_SPECIFIED;
+		mr.range[0].min_ip = mr.range[0].max_ip = newdstip;
+		mr.range[0].min = mr.range[0].max = 
+			((union ip_conntrack_manip_proto ) { newcid }); 
+		DEBUGP("change dest ip to %u.%u.%u.%u\n", 
+			NIPQUAD(newdstip));
+		DEBUGP("change dest key to 0x%x\n", ntohl(newcid));
+		ret = ip_nat_setup_info(ct, &mr, hooknum);
+	} else {
+		if (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.gre.key == htonl(ct_pptp_info->pac_call_id))
+		{
+		newsrcip = master->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
+			newcid = htonl(ct_pptp_info->pns_call_id);
+		}
+		else
+		{
+			/* assume PAC->PNS */
+			newsrcip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip;
+			newcid = htonl(ct_pptp_info->pac_call_id);
+		}
+
+		mr.rangesize = 1;
+		mr.range[0].flags = IP_NAT_RANGE_MAP_IPS
+			            |IP_NAT_RANGE_PROTO_SPECIFIED;
+		mr.range[0].min_ip = mr.range[0].max_ip = newsrcip;
+		mr.range[0].min = mr.range[0].max = 
+			((union ip_conntrack_manip_proto ) { newcid });
+		DEBUGP("change src ip to %u.%u.%u.%u\n", 
+			NIPQUAD(newsrcip));
+		DEBUGP("change 'src' key to 0x%x\n", ntohl(newcid));
+		ret = ip_nat_setup_info(ct, &mr, hooknum);
+	}
+
+	UNLOCK_BH(&ip_pptp_lock);
+
+	return ret;
+
+}
+
+/* outbound packets == from PNS to PAC */
+static inline unsigned int
+pptp_outbound_pkt(struct tcphdr *tcph, struct pptp_pkt_hdr *pptph,
+		  size_t datalen,
+		  struct ip_conntrack *ct,
+		  enum ip_conntrack_info ctinfo,
+		  struct ip_conntrack_expect *exp)
+
+{
+	struct PptpControlHeader *ctlh;
+	union pptp_ctrl_union pptpReq;
+	struct ip_ct_pptp_master *ct_pptp_info = &ct->help.ct_pptp_info;
+	struct ip_nat_pptp *nat_pptp_info = &ct->nat.help.nat_pptp_info;
+
+	u_int16_t msg, *cid = NULL, new_callid;
+
+	ctlh = (struct PptpControlHeader *) ((void *) pptph + sizeof(*pptph));
+	pptpReq.rawreq = (void *) ((void *) ctlh + sizeof(*ctlh));
+
+	new_callid = htons(ct_pptp_info->pns_call_id);
+	
+	switch (msg = ntohs(ctlh->messageType)) {
+		case PPTP_OUT_CALL_REQUEST:
+			cid = &pptpReq.ocreq->callID;
+
+			/* save original call ID in nat_info */
+			nat_pptp_info->pns_call_id = ct_pptp_info->pns_call_id;
+
+			new_callid = tcph->source;
+			/* save new call ID in ct info */
+			ct_pptp_info->pns_call_id = ntohs(new_callid);
+			break;
+		case PPTP_IN_CALL_REPLY:
+			cid = &pptpReq.icreq->callID;
+			break;
+		case PPTP_CALL_CLEAR_REQUEST:
+			cid = &pptpReq.clrreq->callID;
+			break;
+		case PPTP_CALL_DISCONNECT_NOTIFY:
+			cid = &pptpReq.disc->callID;
+			break;
+
+		default:
+			DEBUGP("unknown outbound packet 0x%04x:%s\n", msg,
+			      (msg <= PPTP_MSG_MAX)? strMName[msg]:strMName[0]);
+			/* fall through */
+
+		case PPTP_SET_LINK_INFO:
+			/* only need to NAT in case PAC is behind NAT box */
+		case PPTP_START_SESSION_REQUEST:
+		case PPTP_START_SESSION_REPLY:
+		case PPTP_STOP_SESSION_REQUEST:
+		case PPTP_STOP_SESSION_REPLY:
+		case PPTP_ECHO_REQUEST:
+		case PPTP_ECHO_REPLY:
+			/* no need to alter packet */
+		DEBUGP("outbound control message %s\n", strMName[msg]);
+		DEBUGP("ct->pac_call_id = %d\n", ct_pptp_info->pac_call_id);
+		DEBUGP("ct->pns_call_id = %d\n", ct_pptp_info->pns_call_id);
+		DEBUGP("nat->pac_call_id = %d\n", nat_pptp_info->pac_call_id);
+		DEBUGP("nat->pns_call_id = %d\n", nat_pptp_info->pns_call_id);
+			return NF_ACCEPT;
+	}
+
+	IP_NF_ASSERT(cid);
+
+	DEBUGP("altering call id from 0x%04x to 0x%04x\n",
+		ntohs(*cid), ntohs(new_callid));
+	/* mangle packet */
+	tcph->check = ip_nat_cheat_check(*cid^0xFFFF, 
+					 new_callid, tcph->check);
+	*cid = new_callid;
+
+		DEBUGP("outbound control message %s\n", strMName[msg]);
+		DEBUGP("ct->pac_call_id = %d\n", ct_pptp_info->pac_call_id);
+		DEBUGP("ct->pns_call_id = %d\n", ct_pptp_info->pns_call_id);
+		DEBUGP("nat->pac_call_id = %d\n", nat_pptp_info->pac_call_id);
+		DEBUGP("nat->pns_call_id = %d\n", nat_pptp_info->pns_call_id);
+	return NF_ACCEPT;
+}
+
+/* inbound packets == from PAC to PNS */
+static inline unsigned int
+pptp_inbound_pkt(struct tcphdr *tcph, struct pptp_pkt_hdr *pptph,
+		 size_t datalen,
+		 struct ip_conntrack *ct,
+		 enum ip_conntrack_info ctinfo,
+		 struct ip_conntrack_expect *oldexp)
+{
+	struct PptpControlHeader *ctlh;
+	union pptp_ctrl_union pptpReq;
+	struct ip_ct_pptp_master *ct_pptp_info = &ct->help.ct_pptp_info;
+	struct ip_nat_pptp *nat_pptp_info = &ct->nat.help.nat_pptp_info;
+
+	u_int16_t msg, new_cid = 0, new_pcid, *pcid = NULL, *cid = NULL;
+	u_int32_t old_dst_ip;
+
+	struct ip_conntrack_tuple t;
+
+	ctlh = (struct PptpControlHeader *) ((void *) pptph + sizeof(*pptph));
+	pptpReq.rawreq = (void *) ((void *) ctlh + sizeof(*ctlh));
+
+	new_pcid = htons(nat_pptp_info->pns_call_id);
+
+	switch (msg = ntohs(ctlh->messageType)) {
+	case PPTP_OUT_CALL_REPLY:
+		pcid = &pptpReq.ocack->peersCallID;	
+		cid = &pptpReq.ocack->callID;
+		if (!oldexp) {
+			DEBUGP("outcall but no expectation\n");
+			break;
+		}
+		old_dst_ip = oldexp->tuple.dst.ip;
+		t = oldexp->tuple;
+
+		/* save original PAC call ID in nat_info */
+		nat_pptp_info->pac_call_id = ct_pptp_info->pac_call_id;
+
+		/* store new callID in ct_info, so conntrack works */
+		//ct_pptp_info->pac_call_id = ntohs(tcph->source);
+		//new_cid = htons(ct_pptp_info->pac_call_id);
+
+		/* alter expectation */
+		if (t.dst.ip == ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip) {
+			/* expectation for PNS->PAC direction */
+			t.dst.u.gre.key = htonl(ct_pptp_info->pac_call_id);
+			t.src.u.gre.key = htonl(nat_pptp_info->pns_call_id);
+		} else {
+			/* expectation for PAC->PNS direction */
+			t.dst.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
+			DEBUGP("EXPECTATION IN WRONG DIRECTION!!!\n");
+		}
+
+		if (!ip_conntrack_change_expect(oldexp, &t)) {
+			DEBUGP("successfully changed expect\n");
+		} else {
+			DEBUGP("can't change expect\n");
+		}
+		ip_ct_gre_keymap_change(oldexp->proto.gre.keymap_orig, &t);
+		/* reply keymap */
+		t.src.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip;
+		t.dst.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
+		t.src.u.gre.key = htonl(nat_pptp_info->pac_call_id);
+		t.dst.u.gre.key = htonl(ct_pptp_info->pns_call_id);
+		ip_ct_gre_keymap_change(oldexp->proto.gre.keymap_reply, &t);
+
+		break;
+	case PPTP_IN_CALL_CONNECT:
+		pcid = &pptpReq.iccon->peersCallID;
+		if (!oldexp)
+			break;
+		old_dst_ip = oldexp->tuple.dst.ip;
+		t = oldexp->tuple;
+
+		/* alter expectation, no need for callID */
+		if (t.dst.ip == ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip) {
+			/* expectation for PNS->PAC direction */
+			t.src.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
+		} else {
+			/* expectation for PAC->PNS direction */
+			t.dst.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
+		}
+
+		if (!ip_conntrack_change_expect(oldexp, &t)) {
+			DEBUGP("successfully changed expect\n");
+		} else {
+			DEBUGP("can't change expect\n");
+		}
+		break;
+	case PPTP_IN_CALL_REQUEST:
+		/* only need to nat in case PAC is behind NAT box */
+		break;
+	case PPTP_WAN_ERROR_NOTIFY:
+		pcid = &pptpReq.wanerr->peersCallID;
+		break;
+	case PPTP_SET_LINK_INFO:
+		pcid = &pptpReq.setlink->peersCallID;
+		break;
+	default:
+		DEBUGP("unknown inbound packet %s\n",
+			(msg <= PPTP_MSG_MAX)? strMName[msg]:strMName[0]);
+		/* fall through */
+
+	case PPTP_START_SESSION_REQUEST:
+	case PPTP_START_SESSION_REPLY:
+	case PPTP_STOP_SESSION_REQUEST:
+	case PPTP_ECHO_REQUEST:
+	case PPTP_ECHO_REPLY:
+		/* no need to alter packet */
+		DEBUGP("inbound control message %s\n", strMName[msg]);
+		DEBUGP("ct->pac_call_id = %d\n", ct_pptp_info->pac_call_id);
+		DEBUGP("ct->pns_call_id = %d\n", ct_pptp_info->pns_call_id);
+		DEBUGP("nat->pac_call_id = %d\n", nat_pptp_info->pac_call_id);
+		DEBUGP("nat->pns_call_id = %d\n", nat_pptp_info->pns_call_id);
+		return NF_ACCEPT;
+	}
+
+	/* mangle packet */
+	IP_NF_ASSERT(pcid);
+	DEBUGP("altering peer call id from 0x%04x to 0x%04x\n",
+		ntohs(*pcid), ntohs(new_pcid));
+	tcph->check = ip_nat_cheat_check(*pcid^0xFFFF, 
+					 new_pcid, tcph->check);
+	*pcid = new_pcid;
+
+	if (new_cid) {
+		IP_NF_ASSERT(cid);
+		DEBUGP("altering call id from 0x%04x to 0x%04x\n",
+			ntohs(*cid), ntohs(new_cid));
+		tcph->check = ip_nat_cheat_check(*cid^0xFFFF,
+						new_cid, tcph->check);
+		*cid = new_cid;
+	}
+
+	/* great, at least we don't need to resize packets */
+		DEBUGP("inbound control message %s\n", strMName[msg]);
+		DEBUGP("ct->pac_call_id = %d\n", ct_pptp_info->pac_call_id);
+		DEBUGP("ct->pns_call_id = %d\n", ct_pptp_info->pns_call_id);
+		DEBUGP("nat->pac_call_id = %d\n", nat_pptp_info->pac_call_id);
+		DEBUGP("nat->pns_call_id = %d\n", nat_pptp_info->pns_call_id);
+	return NF_ACCEPT;
+}
+
+
+static unsigned int tcp_help(struct ip_conntrack *ct,
+			     struct ip_conntrack_expect *exp,
+			     struct ip_nat_info *info,
+			     enum ip_conntrack_info ctinfo,
+			     unsigned int hooknum, struct sk_buff **pskb)
+{
+	struct iphdr *iph = (*pskb)->nh.iph;
+	struct tcphdr *tcph = (void *) iph + iph->ihl*4;
+	unsigned int datalen = (*pskb)->len - iph->ihl*4 - tcph->doff*4;
+	struct pptp_pkt_hdr *pptph;
+
+	int dir;
+
+	DEBUGP("entering\n");
+
+	/* Only mangle things once: original direction in POST_ROUTING
+	   and reply direction on PRE_ROUTING. */
+	dir = CTINFO2DIR(ctinfo);
+	if (!((HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC && dir == IP_CT_DIR_ORIGINAL)
+		|| (HOOK2MANIP(hooknum) == IP_NAT_MANIP_DST && dir == IP_CT_DIR_REPLY)))
+	{
+		DEBUGP("Not touching dir %s at hook %s\n",
+		       dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY",
+		       hooknum == NF_IP_POST_ROUTING ? "POSTROUTING"
+		       : hooknum == NF_IP_PRE_ROUTING ? "PREROUTING"
+		       : hooknum == NF_IP_LOCAL_OUT ? "OUTPUT"
+		       : hooknum == NF_IP_LOCAL_IN ? "INPUT" : "???");
+		return NF_ACCEPT;
+	}
+
+	/* if packet is too small, just skip it */
+	if (datalen < sizeof(struct pptp_pkt_hdr)+
+		      sizeof(struct PptpControlHeader)) {
+		DEBUGP("pptp packet too short\n");
+		return NF_ACCEPT;	
+	}
+
+
+	pptph = (struct pptp_pkt_hdr *) ((void *)tcph + tcph->doff*4);
+
+	/* if it's not a control message, we can't handle it */
+	if (ntohs(pptph->packetType) != PPTP_PACKET_CONTROL ||
+		ntohl(pptph->magicCookie) != PPTP_MAGIC_COOKIE)
+	{
+		DEBUGP("not a pptp control packet\n");
+		return NF_ACCEPT;
+	}
+
+	LOCK_BH(&ip_pptp_lock);
+
+	if (dir == IP_CT_DIR_ORIGINAL) {
+		/* reuqests sent by client to server (PNS->PAC) */
+		pptp_outbound_pkt(tcph, pptph, datalen, ct, ctinfo, exp);
+	} else {
+		/* response from the server to the client (PAC->PNS) */
+		pptp_inbound_pkt(tcph, pptph, datalen, ct, ctinfo, exp);
+	}
+
+	UNLOCK_BH(&ip_pptp_lock);
+
+	return NF_ACCEPT;
+}
+
+/* nat helper struct for control connection */
+static struct ip_nat_helper pptp_tcp_helper = { 
+	{ NULL, NULL },
+	"pptp", IP_NAT_HELPER_F_ALWAYS, THIS_MODULE,
+	{ { 0, { tcp: { port: __constant_htons(PPTP_CONTROL_PORT) } } },
+	  { 0, { 0 }, IPPROTO_TCP } },
+	{ { 0, { tcp: { port: 0xFFFF } } },
+	  { 0, { 0 }, 0xFFFF } },
+	tcp_help, pptp_nat_expected };
+
+			  
+static int __init init(void)
+{
+	DEBUGP("init_module\n" );
+
+        if (ip_nat_helper_register(&pptp_tcp_helper))
+		return -EIO;
+
+        return 0;
+}
+
+static void __exit fini(void)
+{
+	DEBUGP("cleanup_module\n" );
+        ip_nat_helper_unregister(&pptp_tcp_helper);
+}
+
+module_init(init);
+module_exit(fini);