patch-2.1.73 linux/net/ipv4/ip_masq_vdolive.c

• Lines: 292
• Date: Wed Dec 10 09:45:16 1997
• Orig file: v2.1.72/linux/net/ipv4/ip_masq_vdolive.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.72/linux/net/ipv4/ip_masq_vdolive.c linux/net/ipv4/ip_masq_vdolive.c
@@ -0,0 +1,291 @@
+/*
+ *		IP_MASQ_VDOLIVE  - VDO Live masquerading module
+ *
+ *
+ * Version:	@(#)$Id: ip_masq_vdolive.c,v 1.2 1997/11/28 15:32:35 alan Exp $
+ *
+ * Author:	Nigel Metheringham <Nigel.Metheringham@ThePLAnet.net>
+ *		PLAnet Online Ltd
+ *
+ * Fixes:	Minor changes for 2.1 by
+ *		Steven Clarke <Steven.Clarke@ThePlanet.Net>, Planet Online Ltd
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ *
+ * Thanks:
+ *	Thank you to VDOnet Corporation for allowing me access to
+ *	a protocol description without an NDA.  This means that
+ *	this module can be distributed as source - a great help!
+ *	
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <asm/system.h>
+#include <linux/skbuff.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/init.h>
+#include <net/protocol.h>
+#include <net/tcp.h>
+#include <net/ip_masq.h>
+
+struct vdolive_priv_data {
+	/* Ports used */
+	unsigned short	origport;
+	unsigned short	masqport;
+	/* State of decode */
+	unsigned short	state;
+};
+
+/* 
+ * List of ports (up to MAX_MASQ_APP_PORTS) to be handled by helper
+ * First port is set to the default port.
+ */
+static int ports[MAX_MASQ_APP_PORTS] = {7000}; /* I rely on the trailing items being set to zero */
+struct ip_masq_app *masq_incarnations[MAX_MASQ_APP_PORTS];
+
+/*
+ *     Debug level
+ */
+static int debug=0;
+
+MODULE_PARM(ports, "1-" __MODULE_STRING(MAX_MASQ_APP_PORTS) "i");
+MODULE_PARM(debug, "i");
+
+static int
+masq_vdolive_init_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
+{
+	MOD_INC_USE_COUNT;
+	if ((ms->app_data = kmalloc(sizeof(struct vdolive_priv_data),
+				    GFP_ATOMIC)) == NULL) 
+		IP_MASQ_DEBUG(1-debug, "VDOlive: No memory for application data\n");
+	else 
+	{
+		struct vdolive_priv_data *priv = 
+			(struct vdolive_priv_data *)ms->app_data;
+		priv->origport = 0;
+		priv->masqport = 0;
+		priv->state = 0;
+	}
+        return 0;
+}
+
+static int
+masq_vdolive_done_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
+{
+        MOD_DEC_USE_COUNT;
+	if (ms->app_data)
+		kfree_s(ms->app_data, sizeof(struct vdolive_priv_data));
+        return 0;
+}
+
+int
+masq_vdolive_out (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, __u32 maddr)
+{
+        struct sk_buff *skb;
+	struct iphdr *iph;
+	struct tcphdr *th;
+	char *data, *data_limit;
+	unsigned int tagval;	/* This should be a 32 bit quantity */
+	struct ip_masq *n_ms;
+	struct vdolive_priv_data *priv = 
+		(struct vdolive_priv_data *)ms->app_data;
+
+	/* This doesn't work at all if no priv data was allocated on startup */
+	if (!priv)
+		return 0;
+
+	/* Everything running correctly already */
+	if (priv->state == 3)
+		return 0;
+
+        skb = *skb_p;
+	iph = skb->nh.iph;
+        th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
+        data = (char *)&th[1];
+
+        data_limit = skb->h.raw + skb->len;
+
+	if (data+8 > data_limit) {
+		IP_MASQ_DEBUG(1-debug, "VDOlive: packet too short for ID %p %p\n", data, data_limit);
+		return 0;
+	}
+	memcpy(&tagval, data+4, 4);
+	IP_MASQ_DEBUG(1-debug, "VDOlive: packet seen, tag %ld, in initial state %d\n", ntohl(tagval), priv->state);
+
+	/* Check for leading packet ID */
+	if ((ntohl(tagval) != 6) && (ntohl(tagval) != 1)) {
+		IP_MASQ_DEBUG(1-debug, "VDOlive: unrecognised tag %ld, in initial state %d\n", ntohl(tagval), priv->state);
+		return 0;
+	}
+		
+
+	/* Check packet is long enough for data - ignore if not */
+	if ((ntohl(tagval) == 6) && (data+36 > data_limit)) {
+		IP_MASQ_DEBUG(1-debug, "VDOlive: initial packet too short %p %p\n", data, data_limit);
+		return 0;
+	} else if ((ntohl(tagval) == 1) && (data+20 > data_limit)) {
+		IP_MASQ_DEBUG(1-debug,"VDOlive: secondary packet too short %p %p\n", data, data_limit);
+		return 0;
+	}
+
+	/* Adjust data pointers */
+	/*
+	 * I could check the complete protocol version tag 
+	 * in here however I am just going to look for the
+	 * "VDO Live" tag in the hope that this part will
+	 * remain constant even if the version changes
+	 */
+	if (ntohl(tagval) == 6) {
+		data += 24;
+		IP_MASQ_DEBUG(1-debug, "VDOlive: initial packet found\n");
+	} else {
+		data += 8;
+		IP_MASQ_DEBUG(1-debug, "VDOlive: secondary packet found\n");
+	}
+
+	if (memcmp(data, "VDO Live", 8) != 0) {
+		IP_MASQ_DEBUG(1-debug,"VDOlive: did not find tag\n");
+		return 0;
+	}
+	/* 
+	 * The port number is the next word after the tag.
+	 * VDOlive encodes all of these values
+	 * in 32 bit words, so in this case I am
+	 * skipping the first 2 bytes of the next
+	 * word to get to the relevant 16 bits
+	 */
+	data += 10;
+
+	/*
+	 * If we have not seen the port already,
+	 * set the masquerading tunnel up
+	 */
+	if (!priv->origport) {
+		memcpy(&priv->origport, data, 2);
+		IP_MASQ_DEBUG(1-debug, "VDOlive: found port %d\n", ntohs(priv->origport));
+
+		/* Open up a tunnel */
+		n_ms = ip_masq_new(IPPROTO_UDP,
+				   maddr, 0,
+				   ms->saddr, priv->origport,
+				   ms->daddr, 0,
+				   IP_MASQ_F_NO_DPORT);
+					
+		if (n_ms==NULL) {
+		        ip_masq_put(n_ms);
+			IP_MASQ_DEBUG(1-debug, "VDOlive: unable to build UDP tunnel for %x:%x\n", ms->saddr, priv->origport);
+			/* Leave state as unset */
+			priv->origport = 0;
+			return 0;
+		}
+		ip_masq_listen(n_ms);
+
+		ip_masq_put(ms);
+		priv->masqport = n_ms->mport;
+	} else if (memcmp(data, &(priv->origport), 2)) {
+		IP_MASQ_DEBUG(1-debug, "VDOlive: ports do not match\n");
+		/* Write the port in anyhow!!! */
+	}
+
+	/*
+	 * Write masq port into packet
+	 */
+	memcpy(data, &(priv->masqport), 2);
+	IP_MASQ_DEBUG(1-debug, "VDOlive: rewrote port %d to %d, server %08X\n", ntohs(priv->origport), ntohs(priv->masqport), ms->saddr);
+
+	/*
+	 * Set state bit to make which bit has been done
+	 */
+
+	priv->state |= (ntohl(tagval) == 6) ? 1 : 2;
+
+	return 0;
+}
+
+
+struct ip_masq_app ip_masq_vdolive = {
+        NULL,			/* next */
+	"VDOlive",	       	/* name */
+        0,                      /* type */
+        0,                      /* n_attach */
+        masq_vdolive_init_1,	/* ip_masq_init_1 */
+        masq_vdolive_done_1,	/* ip_masq_done_1 */
+        masq_vdolive_out,	/* pkt_out */
+        NULL                    /* pkt_in */
+};
+
+/*
+ * 	ip_masq_vdolive initialization
+ */
+
+__initfunc(int ip_masq_vdolive_init(void))
+{
+	int i, j;
+
+	for (i=0; (i<MAX_MASQ_APP_PORTS); i++) {
+		if (ports[i]) {
+			if ((masq_incarnations[i] = kmalloc(sizeof(struct ip_masq_app),
+							    GFP_KERNEL)) == NULL)
+				return -ENOMEM;
+			memcpy(masq_incarnations[i], &ip_masq_vdolive, sizeof(struct ip_masq_app));
+			if ((j = register_ip_masq_app(masq_incarnations[i], 
+						      IPPROTO_TCP, 
+						      ports[i]))) {
+				return j;
+			}
+			IP_MASQ_DEBUG(1-debug, "RealAudio: loaded support on port[%d] = %d\n", i, ports[i]);
+		} else {
+			/* To be safe, force the incarnation table entry to NULL */
+			masq_incarnations[i] = NULL;
+		}
+	}
+	return 0;
+}
+
+/*
+ * 	ip_masq_vdolive fin.
+ */
+
+int ip_masq_vdolive_done(void)
+{
+	int i, j, k;
+
+	k=0;
+	for (i=0; (i<MAX_MASQ_APP_PORTS); i++) {
+		if (masq_incarnations[i]) {
+			if ((j = unregister_ip_masq_app(masq_incarnations[i]))) {
+				k = j;
+			} else {
+				kfree(masq_incarnations[i]);
+				masq_incarnations[i] = NULL;
+				IP_MASQ_DEBUG(1-debug,"VDOlive: unloaded support on port[%d] = %d\n", i, ports[i]);
+			}
+		}
+	}
+	return k;
+}
+
+
+#ifdef MODULE
+EXPORT_NO_SYMBOLS;
+
+int init_module(void)
+{
+        if (ip_masq_vdolive_init() != 0)
+                return -EIO;
+        return 0;
+}
+
+void cleanup_module(void)
+{
+        if (ip_masq_vdolive_done() != 0)
+                IP_MASQ_DEBUG(1-debug, "ip_masq_vdolive: can't remove module");
+}
+
+#endif /* MODULE */