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

• Lines: 262
• Date: Wed Dec 10 09:45:16 1997
• Orig file: v2.1.72/linux/net/ipv4/ip_masq_cuseeme.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.72/linux/net/ipv4/ip_masq_cuseeme.c linux/net/ipv4/ip_masq_cuseeme.c
@@ -0,0 +1,261 @@
+/*
+ *		IP_MASQ_FTP CUSeeMe masquerading module
+ *
+ *
+ * Version:	@(#)$Id: ip_masq_cuseeme.c,v 1.2 1997/11/28 15:32:18 alan Exp $
+ *
+ * Author:	Richard Lynch
+ *		
+ *
+ * Fixes:
+ *	Richard Lynch     	:	Updated patch to conform to new module
+ *					specifications
+ *	Nigel Metheringham	:	Multiple port support
+ *	Michael Owings		:	Fixed broken init code
+ *					Added code to update inbound
+ *					packets with correct local addresses.
+ *					Fixes audio and "chat" problems
+ *					Thanx to the CU-SeeMe Consortium for
+ *					technical docs
+ *	Steven Clarke		:	Small changes for 2.1	
+ *
+ *
+ *
+ *	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.
+ *	
+ * Multiple Port Support
+ *	The helper can be made to handle up to MAX_MASQ_APP_PORTS (normally 12)
+ *	with the port numbers being defined at module load time.  The module
+ *	uses the symbol "ports" to define a list of monitored ports, which can
+ *	be specified on the insmod command line as
+ *		ports=x1,x2,x3...
+ *	where x[n] are integer port numbers.  This option can be put into
+ *	/etc/conf.modules (or /etc/modules.conf depending on your config)
+ *	where modload will pick it up should you use modload to load your
+ *	modules.
+ *	
+ */
+
+#include <linux/module.h>
+#include <asm/system.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/init.h>
+#include <net/protocol.h>
+#include <net/udp.h>
+
+/* #define IP_MASQ_NDEBUG */
+#include <net/ip_masq.h>
+
+#pragma pack(1)
+/* CU-SeeMe Data Header */
+typedef struct {
+	u_short 	dest_family;
+	u_short 	dest_port;
+	u_long  	dest_addr;
+	short 		family;
+	u_short 	port;
+	u_long 		addr;
+	u_long 		seq;
+	u_short 	msg;
+	u_short		data_type;
+	u_short		packet_len;
+} cu_header;
+
+/* Open Continue Header */
+typedef struct	{
+	cu_header	cu_head;
+	u_short 	client_count; /* Number of client info structs */
+	u_long		seq_no;
+	char		user_name[20];
+	char		stuff[4]; /* flags,  version stuff,  etc */
+}oc_header;
+
+/* client info structures */
+typedef struct {
+	u_long		address; /* Client address */
+	char	       	stuff[8]; /* Flags, pruning bitfield,  packet counts etc */
+} client_info;
+#pragma pack()
+
+/*
+ * 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] = {7648}; /* 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_cuseeme_init_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
+{
+        MOD_INC_USE_COUNT;
+        return 0;
+}
+
+static int
+masq_cuseeme_done_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
+{
+        MOD_DEC_USE_COUNT;
+        return 0;
+}
+
+int
+masq_cuseeme_out (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, __u32 maddr)
+{
+	struct sk_buff *skb = *skb_p;
+	struct iphdr *iph = skb->nh.iph;
+	struct udphdr *uh = (struct udphdr *)&(((char *)iph)[iph->ihl*4]);
+	cu_header *cu_head;
+	char *data=(char *)&uh[1];
+
+	if (skb->len - ((unsigned char *) data - skb->h.raw) >= sizeof(cu_header))
+	{
+		cu_head         = (cu_header *) data;
+		/* cu_head->port   = ms->mport; */
+	        if( cu_head->addr )
+		cu_head->addr = (u_long) maddr;
+	        if(ntohs(cu_head->data_type) == 257)
+		        IP_MASQ_DEBUG(1-debug, "Sending talk packet!\n");
+	}
+	return 0;
+}
+
+int
+masq_cuseeme_in (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, __u32 maddr)
+{
+	struct sk_buff *skb = *skb_p;
+	struct iphdr *iph = skb->nh.iph;
+	struct udphdr *uh = (struct udphdr *)&(((char *)iph)[iph->ihl*4]);
+	cu_header *cu_head;
+	oc_header	*oc;
+	client_info	*ci;
+	char *data=(char *)&uh[1];
+	u_short len = skb->len - ((unsigned char *) data - skb->h.raw);
+	int		i, off;
+
+	if (len >= sizeof(cu_header))
+	{
+		cu_head         = (cu_header *) data;
+		if(cu_head->dest_addr) /* Correct destination address */
+			cu_head->dest_addr = (u_long) ms->saddr;
+		if(ntohs(cu_head->data_type)==101 && len > sizeof(oc_header))
+		{
+			oc = (oc_header * ) data;
+			/* Spin (grovel) thru client_info structs till we find our own */
+		        off=sizeof(oc_header);
+			for(i=0;
+			    (i < oc->client_count && off+sizeof(client_info) <= len);
+			    i++)		    
+			{
+			        ci=(client_info *)(data+off);
+				if(ci->address==(u_long) maddr)
+				{
+				        /* Update w/ our real ip address and exit */
+					ci->address = (u_long) ms->saddr;
+					break;
+				}
+			        else
+				   off+=sizeof(client_info);
+			}
+		}
+	}
+	return 0;
+}
+
+struct ip_masq_app ip_masq_cuseeme = {
+        NULL,			/* next */
+        "cuseeme",
+        0,                      /* type */
+        0,                      /* n_attach */
+        masq_cuseeme_init_1,	/* ip_masq_init_1 */
+        masq_cuseeme_done_1,	/* ip_masq_done_1 */
+        masq_cuseeme_out,	/* pkt_out */
+        masq_cuseeme_in    	/* pkt_in */
+};
+
+
+/*
+ * 	ip_masq_cuseeme initialization
+ */
+
+__initfunc(int ip_masq_cuseeme_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_cuseeme, sizeof(struct ip_masq_app));
+			if ((j = register_ip_masq_app(masq_incarnations[i], 
+						      IPPROTO_UDP,
+						      ports[i]))) {
+				return j;
+			}
+#if DEBUG_CONFIG_IP_MASQ_CUSEEME
+			IP_MASQ_DEBUG(1-debug, "CuSeeMe: loaded support on port[%d] = %d\n",
+			       i, ports[i]);
+#endif
+		} else {
+			/* To be safe, force the incarnation table entry to NULL */
+			masq_incarnations[i] = NULL;
+		}
+	}
+	return 0;
+}
+
+/*
+ * 	ip_masq_cuseeme fin.
+ */
+
+int ip_masq_cuseeme_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, "CuSeeMe: unloaded support on port[%d] = %d\n", i, ports[i]);
+			}
+		}
+	}
+	return k;
+}
+
+#ifdef MODULE
+EXPORT_NO_SYMBOLS;
+
+int init_module(void)
+{
+        if (ip_masq_cuseeme_init() != 0)
+                return -EIO;
+        return 0;
+}
+
+void cleanup_module(void)
+{
+        if (ip_masq_cuseeme_done() != 0)
+                IP_MASQ_DEBUG(1-debug, "ip_masq_cuseeme: can't remove module");
+}
+
+#endif /* MODULE */