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

• Lines: 549
• Date: Wed Dec 10 09:45:16 1997
• Orig file: v2.1.72/linux/net/ipv4/ip_masq_raudio.c
• Orig date: Mon Dec 1 12:04:16 1997

diff -u --recursive --new-file v2.1.72/linux/net/ipv4/ip_masq_raudio.c linux/net/ipv4/ip_masq_raudio.c
@@ -2,11 +2,13 @@
  *		IP_MASQ_RAUDIO  - Real Audio masquerading module
  *
  *
- * Version:	@(#)$Id: ip_masq_raudio.c,v 1.7 1997/09/16 18:43:40 kuznet Exp $
+ * Version:	@(#)$Id: ip_masq_raudio.c,v 1.8 1997/11/28 15:32:32 alan Exp $
  *
  * Author:	Nigel Metheringham
+ *		Real Time Streaming code by Progressive Networks
  *		[strongly based on ftp module by Juan Jose Ciarlante & Wouter Gadeyne]
  *		[Real Audio information taken from Progressive Networks firewall docs]
+ *		[Kudos to Progressive Networks for making the protocol specs available]
  *
  *
  *
@@ -31,16 +33,40 @@
  *
  *	At present the "first packet" is defined as a packet starting with
  *	the protocol ID string - "PNA".
- *	When the link is up there appears to be enough control data
+ *	When the link is up there appears to be enough control data 
  *	crossing the control link to keep it open even if a long audio
  *	piece is playing.
  *
+ *	The Robust UDP support added in RealAudio 3.0 is supported, but due
+ *	to servers/clients not making great use of this has not been greatly
+ *	tested.  RealVideo (as used in the Real client version 4.0beta1) is
+ *	supported but again is not greatly tested (bandwidth requirements
+ *	appear to exceed that available at the sites supporting the protocol).
+ *
+ * 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.
+ *
+ * Fixes:
+ * 	Juan Jose Ciarlante	:	Use control_add() for control chan
+ * 	10/15/97 - Modifications to allow masquerading of RTSP connections as
+ *     		well as PNA, which can potentially exist on the same port.
+ *		Joe Rumsey <ogre@real.com>
+ *	
  */
 
 #include <linux/config.h>
 #include <linux/module.h>
 #include <asm/system.h>
 #include <linux/types.h>
+#include <linux/ctype.h>
 #include <linux/kernel.h>
 #include <linux/skbuff.h>
 #include <linux/in.h>
@@ -50,30 +76,62 @@
 #include <net/tcp.h>
 #include <net/ip_masq.h>
 
+/*
 #ifndef DEBUG_CONFIG_IP_MASQ_RAUDIO
 #define DEBUG_CONFIG_IP_MASQ_RAUDIO 0
 #endif
+*/
+
+#define TOLOWER(c) (((c) >= 'A' && (c) <= 'Z') ? ((c) - 'A' + 'a') : (c))
+#define ISDIGIT(c) (((c) >= '0') && ((c) <= '9'))
 
 struct raudio_priv_data {
 	/* Associated data connection - setup but not used at present */
 	struct	ip_masq *data_conn;
+	/* UDP Error correction connection - setup but not used at present */
+	struct	ip_masq *error_conn;
 	/* Have we seen and performed setup */
 	short	seen_start;
+        short   is_rtsp;
 };
 
+int
+masq_rtsp_out (struct ip_masq_app *mapp, 
+		 struct ip_masq *ms, 
+		 struct sk_buff **skb_p, 
+		 __u32 maddr);
+
+/* 
+ * List of ports (up to MAX_MASQ_APP_PORTS) to be handled by helper
+ * First port is set to the default port.
+ */
+int ports[MAX_MASQ_APP_PORTS] = {554, 7070, 0}; /* 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_raudio_init_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
 {
         MOD_INC_USE_COUNT;
 	if ((ms->app_data = kmalloc(sizeof(struct raudio_priv_data),
-				    GFP_ATOMIC)) == NULL)
+				    GFP_ATOMIC)) == NULL) 
 		printk(KERN_INFO "RealAudio: No memory for application data\n");
-	else
+	else 
 	{
-		struct raudio_priv_data *priv =
+		struct raudio_priv_data *priv = 
 			(struct raudio_priv_data *)ms->app_data;
 		priv->seen_start = 0;
 		priv->data_conn = NULL;
+		priv->error_conn = NULL;
+		priv->is_rtsp = 0;
 	}
         return 0;
 }
@@ -96,34 +154,43 @@
 	char *p, *data, *data_limit;
 	struct ip_masq *n_ms;
 	unsigned short version, msg_id, msg_len, udp_port;
-	struct raudio_priv_data *priv =
+	struct raudio_priv_data *priv = 
 		(struct raudio_priv_data *)ms->app_data;
 
 	/* Everything running correctly already */
 	if (priv && priv->seen_start)
 		return 0;
 
+	if(priv && priv->is_rtsp)
+	    return masq_rtsp_out(mapp, ms, skb_p, maddr);
+
         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 - 18;
+        data_limit = skb->h.raw + skb->len;
+
+	if(memcmp(data, "OPTIONS", 7) == 0 ||
+	   memcmp(data, "DESCRIBE", 8) == 0)
+	{
+	    IP_MASQ_DEBUG(1-debug, "RealAudio: Detected RTSP connection\n");
+	    /* This is an RTSP client */
+	    if(priv)
+		priv->is_rtsp = 1;
+	    return masq_rtsp_out(mapp, ms, skb_p, maddr);
+	}
 
 	/* Check to see if this is the first packet with protocol ID */
 	if (memcmp(data, "PNA", 3)) {
-#if DEBUG_CONFIG_IP_MASQ_RAUDIO
-		printk("RealAudio: not initial protocol packet - ignored\n");
-#endif
+		IP_MASQ_DEBUG(1-debug, "RealAudio: not initial protocol packet - ignored\n");
 		return(0);
 	}
 	data += 3;
 	memcpy(&version, data, 2);
 
-#if DEBUG_CONFIG_IP_MASQ_RAUDIO
-	printk("RealAudio: initial seen - protocol version %d\n",
+	IP_MASQ_DEBUG(1-debug, "RealAudio: initial seen - protocol version %d\n",
 	       ntohs(version));
-#endif
 	if (priv)
 		priv->seen_start = 1;
 
@@ -135,15 +202,22 @@
 	}
 
 	data += 2;
-	while (data < data_limit) {
+	while (data+4 < data_limit) {
 		memcpy(&msg_id, data, 2);
 		data += 2;
 		memcpy(&msg_len, data, 2);
 		data += 2;
-#if DEBUG_CONFIG_IP_MASQ_RAUDIO
-		printk("RealAudio: msg %d - %d byte\n",
+		if (ntohs(msg_id) == 0) {
+			/* The zero tag indicates the end of options */
+			IP_MASQ_DEBUG(1-debug, "RealAudio: packet end tag seen\n");
+			return 0;
+		}
+		IP_MASQ_DEBUG(1-debug, "RealAudio: msg %d - %d byte\n",
 		       ntohs(msg_id), ntohs(msg_len));
-#endif
+		if (ntohs(msg_id) == 0) {
+			/* The zero tag indicates the end of options */
+			return 0;
+		}
 		p = data;
 		data += ntohs(msg_len);
 		if (data > data_limit)
@@ -151,39 +225,272 @@
 			printk(KERN_INFO "RealAudio: Packet too short for data\n");
 			return 0;
 		}
-		if (ntohs(msg_id) == 1) {
-			/* This is a message detailing the UDP port to be used */
+		if ((ntohs(msg_id) == 1) || (ntohs(msg_id) == 7)) {
+			/* 
+			 * MsgId == 1
+			 * Audio UDP data port on client
+			 *
+			 * MsgId == 7
+			 * Robust UDP error correction port number on client
+			 *
+			 * Since these messages are treated just the same, they
+			 * are bundled together here....
+			 */
 			memcpy(&udp_port, p, 2);
-			n_ms = ip_masq_new(maddr, IPPROTO_UDP,
-					   ms->saddr, udp_port,
-					   ms->daddr, 0,
-					   IP_MASQ_F_NO_DPORT);
+
+			/* 
+			 * Sometimes a server sends a message 7 with a zero UDP port
+			 * Rather than do anything with this, just ignore it!
+			 */
+			if (udp_port == 0)
+				continue;
+
+
+			n_ms = ip_masq_new(IPPROTO_UDP,
+						maddr, 0,
+						ms->saddr, udp_port,
+						ms->daddr, 0,
+						IP_MASQ_F_NO_DPORT);
 
 			if (n_ms==NULL)
 				return 0;
 
+			ip_masq_listen(n_ms);
+			ip_masq_control_add(n_ms, ms);
+
 			memcpy(p, &(n_ms->mport), 2);
-#if DEBUG_CONFIG_IP_MASQ_RAUDIO
-			printk("RealAudio: rewrote UDP port %d -> %d\n",
-			       ntohs(udp_port), ntohs(n_ms->mport));
-#endif
-			ip_masq_set_expire(n_ms, ip_masq_expire->udp_timeout);
+			IP_MASQ_DEBUG(1-debug, "RealAudio: rewrote UDP port %d -> %d in msg %d\n",
+			       ntohs(udp_port), ntohs(n_ms->mport), ntohs(msg_id));
 
 			/* Make ref in application data to data connection */
-			if (priv)
-				priv->data_conn = n_ms;
+			if (priv) {
+				if (ntohs(msg_id) == 1)
+					priv->data_conn = n_ms;
+				else
+					priv->error_conn = n_ms;
+			}
+			
+			ip_masq_put(n_ms);
+		}
+	}
+	return 0;
+}
 
-			/*
-			 * There is nothing else useful we can do
-			 * Maybe a development could do more, but for now
-			 * we exit gracefully!
-			 */
-			return 0;
+/*
+ * masq_rtsp_out
+ *
+ * 
+ */
+int
+masq_rtsp_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;
+	struct ip_masq *n_ms, *n_ms2;
+	unsigned short udp_port;
+	struct raudio_priv_data *priv = 
+		(struct raudio_priv_data *)ms->app_data;
+	const char* srch = "transport:";
+	const char* srchpos = srch;
+	const char* srchend = srch + strlen(srch);
+	int state = 0;
+	char firstport[6];
+	int firstportpos = 0;
+	char secondport[6];
+	int secondportpos = 0;
+	char *portstart = NULL, *portend = NULL;
+	int diff;
 
-		} else if (ntohs(msg_id) == 0)
+	/* Everything running correctly already */
+	if (priv && priv->seen_start)
+		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;
+
+	firstport[0] = 0;
+	secondport[0] = 0;
+
+	while(data < data_limit && state >= 0)
+	{
+	    switch(state)
+	    {
+		case 0:
+		case 1:
+		    if(TOLOWER(*data) == *srchpos)
+		    {
+			srchpos++;
+			if(srchpos == srchend)
+			{
+			    IP_MASQ_DEBUG(1-debug, "Found string %s in message\n",
+				   srch);
+			    state++;
+			    if(state == 1)
+			    {
+				srch = "client_port";
+				srchpos = srch;
+				srchend = srch + strlen(srch);
+			    }
+			}
+		    }
+		    else
+		    {
+			srchpos = srch;
+		    }
+		    break;
+		case 2:
+		    if(*data == '=')
+			state = 3;
+		    break;
+		case 3:
+		    if(ISDIGIT(*data))
+		    {
+			portstart = data;
+			firstportpos = 0;
+			firstport[firstportpos++] = *data;
+			state = 4;
+		    }
+		    break;
+		case 4:
+		    if(*data == '-')
+		    {
+			state = 5;
+		    }
+		    else if(*data == ';')
+		    {
+			portend = data - 1;
+			firstport[firstportpos] = 0;
+			state = -1;
+		    }
+		    else if(ISDIGIT(*data))
+		    {
+			firstport[firstportpos++] = *data;
+		    }
+		    else if(*data != ' ' && *data != '\t')
+		    {
+			/* This is a badly formed RTSP message, let's bail out */
+			IP_MASQ_DEBUG(1-debug, "Badly formed RTSP Message\n");
 			return 0;
+		    }
+		    break;
+		case 5:
+		    if(ISDIGIT(*data))
+		    {
+			secondportpos = 0;
+			secondport[secondportpos++] = *data;
+			state = 6;
+		    }
+		    else if(*data == ';')
+		    {
+			portend = data - 1;
+			secondport[secondportpos] = 0;
+			state = -1;
+		    }
+		    break;
+		case 6:
+		    if(*data == ';')
+		    {
+			portend = data - 1;
+			secondport[secondportpos] = 0;
+			state = -1;
+		    }
+		    else if(ISDIGIT(*data))
+		    {
+			secondport[secondportpos++] = *data;
+		    }
+		    else if(*data != ' ' && *data != '\t')
+		    {
+			/* This is a badly formed RTSP message, let's bail out */
+			IP_MASQ_DEBUG(1-debug, "Badly formed RTSP Message\n");
+			return 0;
+		    }
+		    break;
+	    }
+	    data++;
 	}
-	return 0;
+
+	if(state >= 0)
+	    return 0;
+
+	if(firstportpos > 0)
+	{
+	    char newbuf[12]; /* xxxxx-xxxxx\0 */
+	    char* tmpptr;
+
+	    udp_port = htons(simple_strtoul(firstport, &tmpptr, 10));
+	    n_ms = ip_masq_new(IPPROTO_UDP,
+			       maddr, 0,
+			       ms->saddr, udp_port,
+			       ms->daddr, 0,
+			       IP_MASQ_F_NO_DPORT);
+	    if (n_ms==NULL)
+		return 0;
+	    
+	    ip_masq_listen(n_ms);
+	    ip_masq_control_add(n_ms, ms);
+
+	    if(secondportpos > 0)
+	    {
+		udp_port = htons(simple_strtoul(secondport, &tmpptr, 10));
+		n_ms2 = ip_masq_new(IPPROTO_UDP,
+				maddr, 0,
+				ms->saddr, udp_port,
+				ms->daddr, 0,
+				IP_MASQ_F_NO_DPORT);
+		if (n_ms2==NULL) {
+		    ip_masq_put(n_ms);
+		    return 0;
+		}
+
+		ip_masq_listen(n_ms2);
+		ip_masq_control_add(n_ms2, ms);
+		sprintf(newbuf, "%d-%d", ntohs(n_ms->mport), 
+			ntohs(n_ms2->mport));
+	    }
+	    else
+	    {
+		sprintf(newbuf, "%d", ntohs(n_ms->mport));
+		n_ms2 = NULL;
+	    }
+	    *skb_p = ip_masq_skb_replace(skb, GFP_ATOMIC,
+					 portstart, portend - portstart + 1,
+					 newbuf, strlen(newbuf));
+	    IP_MASQ_DEBUG(1-debug, "RTSP: rewrote client_port to %s\n", newbuf);
+	    diff = strlen(newbuf) - (portend - portstart);
+	}
+	else
+	{
+	    return 0;
+	}
+	    
+	if(priv)
+	{
+	    priv->seen_start = 1;
+	    if(n_ms)
+		priv->data_conn = n_ms;
+	    if(n_ms2)
+		priv->error_conn = n_ms2;
+	}
+	/*
+	 *	Release tunnels
+	 */
+
+	if (n_ms)
+		ip_masq_put(n_ms);
+
+	if (n_ms2)
+		ip_masq_put(n_ms2);
+
+	return diff;
 }
 
 struct ip_masq_app ip_masq_raudio = {
@@ -203,7 +510,27 @@
 
 __initfunc(int ip_masq_raudio_init(void))
 {
-        return register_ip_masq_app(&ip_masq_raudio, IPPROTO_TCP, 7070);
+	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_raudio, 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;
 }
 
 /*
@@ -212,7 +539,22 @@
 
 int ip_masq_raudio_done(void)
 {
-        return unregister_ip_masq_app(&ip_masq_raudio);
+	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, "RealAudio: unloaded support on port[%d] = %d\n",
+				       i, ports[i]);
+			}
+		}
+	}
+	return k;
 }
 
 #ifdef MODULE