patch-2.3.15 linux/net/ipv4/ip_masq_ftp.c

• Lines: 394
• Date: Wed Dec 31 16:00:00 1969
• Orig file: v2.3.14/linux/net/ipv4/ip_masq_ftp.c
• Orig date: Mon Oct 5 12:28:09 1998

diff -u --recursive --new-file v2.3.14/linux/net/ipv4/ip_masq_ftp.c linux/net/ipv4/ip_masq_ftp.c
@@ -1,393 +0,0 @@
-/*
- *		IP_MASQ_FTP ftp masquerading module
- *
- *
- * Version:	@(#)ip_masq_ftp.c 0.04   02/05/96
- *
- * Author:	Wouter Gadeyne
- *		
- *
- * Fixes:
- *	Wouter Gadeyne		:	Fixed masquerading support of ftp PORT commands
- * 	Juan Jose Ciarlante	:	Code moved and adapted from ip_fw.c
- * 	Keith Owens		:	Add keep alive for ftp control channel
- *	Nigel Metheringham	:	Added multiple port support
- * 	Juan Jose Ciarlante	:	Use control_add() for ftp control chan
- * 	Juan Jose Ciarlante	:	Litl bits for 2.1
- *	Juan Jose Ciarlante	:	use ip_masq_listen() 
- *	Juan Jose Ciarlante	: 	use private app_data for own flag(s)
- *
- *
- *
- *	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/config.h>
-#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/tcp.h>
-
-/* #define IP_MASQ_NDEBUG */
-#include <net/ip_masq.h>
-
-
-/* 
- * 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] = {21}; /* I rely on the trailing items being set to zero */
-struct ip_masq_app *masq_incarnations[MAX_MASQ_APP_PORTS];
-
-/*
- *	Debug level
- */
-#ifdef CONFIG_IP_MASQ_DEBUG
-static int debug=0;
-MODULE_PARM(debug, "i");
-#endif
-
-MODULE_PARM(ports, "1-" __MODULE_STRING(MAX_MASQ_APP_PORTS) "i");
-
-/*	Dummy variable */
-static int masq_ftp_pasv;
-
-static int
-masq_ftp_init_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
-{
-        MOD_INC_USE_COUNT;
-        return 0;
-}
-
-static int
-masq_ftp_done_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
-{
-        MOD_DEC_USE_COUNT;
-        return 0;
-}
-
-int
-masq_ftp_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 *p, *data, *data_limit;
-	unsigned char p1,p2,p3,p4,p5,p6;
-	__u32 from;
-	__u16 port;
-	struct ip_masq *n_ms;
-	char buf[24];		/* xxx.xxx.xxx.xxx,ppp,ppp\000 */
-        unsigned buf_len;
-	int diff;
-
-        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;
-        if (skb->len >= 6 && (memcmp(data, "PASV\r\n", 6) == 0 || memcmp(data, "pasv\r\n", 6) == 0))
-		ms->app_data = &masq_ftp_pasv;
-
-	while (data < data_limit)
-	{
-		if (memcmp(data,"PORT ",5) && memcmp(data,"port ",5))
-		{
-			data ++;
-			continue;
-		}
-		p = data+5;
- 		p1 = simple_strtoul(data+5,&data,10);
-		if (*data!=',')
-			continue;
-		p2 = simple_strtoul(data+1,&data,10);
-		if (*data!=',')
-			continue;
-		p3 = simple_strtoul(data+1,&data,10);
-		if (*data!=',')
-			continue;
-		p4 = simple_strtoul(data+1,&data,10);
-		if (*data!=',')
-			continue;
-		p5 = simple_strtoul(data+1,&data,10);
-		if (*data!=',')
-			continue;
-		p6 = simple_strtoul(data+1,&data,10);
-		if (*data!='\r' && *data!='\n')
-			continue;
-
-		from = (p1<<24) | (p2<<16) | (p3<<8) | p4;
-		port = (p5<<8) | p6;
-
-		IP_MASQ_DEBUG(1-debug, "PORT %X:%X detected\n",from,port);
-
-		/*
-		 * Now update or create an masquerade entry for it
-		 */
-
-		IP_MASQ_DEBUG(1-debug, "protocol %d %lX:%X %X:%X\n", iph->protocol, htonl(from), htons(port), iph->daddr, 0);
-
-		n_ms = ip_masq_out_get(iph->protocol,
-					 htonl(from), htons(port),
-					 iph->daddr, 0);
-		if (!n_ms) {
-			n_ms = ip_masq_new(IPPROTO_TCP,
-					   maddr, 0,
-					   htonl(from), htons(port),
-					   iph->daddr, 0,
-					   IP_MASQ_F_NO_DPORT);
-
-			if (n_ms==NULL)
-				return 0;
-			ip_masq_control_add(n_ms, ms);
-		}
-
-		/*
-		 * Replace the old PORT with the new one
-		 */
-		from = ntohl(n_ms->maddr);
-		port = ntohs(n_ms->mport);
-		sprintf(buf,"%d,%d,%d,%d,%d,%d",
-			from>>24&255,from>>16&255,from>>8&255,from&255,
-			port>>8&255,port&255);
-		buf_len = strlen(buf);
-
-		IP_MASQ_DEBUG(1-debug, "new PORT %X:%X\n",from,port);
-
-		/*
-		 * Calculate required delta-offset to keep TCP happy
-		 */
-		
-		diff = buf_len - (data-p);
-		
-		/*
-		 *	No shift.
-		 */
-		
-		if (diff==0) {
-			/*
-			 * simple case, just replace the old PORT cmd
- 			 */
- 			memcpy(p,buf,buf_len);
- 		} else {
-
-			*skb_p = ip_masq_skb_replace(skb, GFP_ATOMIC, p, data-p, buf, buf_len);
-		}
-                /*
-                 * 	Move tunnel to listen state
-                 */
-		ip_masq_listen(n_ms);
-		ip_masq_put(n_ms);
-
-                return diff;
-
-	}
-	return 0;
-
-}
-
-/*
- * Look at incoming ftp packets to catch the response to a PASV command.  When
- * we see one we build a masquerading entry for the client address, client port
- * 0 (unknown at the moment), the server address and the server port.  Mark the
- * current masquerade entry as a control channel and point the new entry at the
- * control entry.  All this work just for ftp keepalive across masquerading.
- *
- * The incoming packet should be something like
- * "227 Entering Passive Mode (xxx,xxx,xxx,xxx,ppp,ppp)".
- * xxx,xxx,xxx,xxx is the server address, ppp,ppp is the server port number.
- * ncftp 2.3.0 cheats by skipping the leading number then going 22 bytes into
- * the data so we do the same.  If it's good enough for ncftp then it's good
- * enough for me.
- *
- * In this case, the client is the source machine being masqueraded, the server
- * is the destination for ftp requests.  It all depends on your point of view ...
- */
-
-int
-masq_ftp_in (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 char p1,p2,p3,p4,p5,p6;
-	__u32 to;
-	__u16 port;
-	struct ip_masq *n_ms;
-
-	if (ms->app_data != &masq_ftp_pasv)
-		return 0;	/* quick exit if no outstanding PASV */
-
-	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;
-
-	while (data < data_limit && *data != ' ')
-		++data;	
-	while (data < data_limit && *data == ' ')
-		++data;	
-	data += 22;
-	if (data >= data_limit || *data != '(')
-		return 0;
-	p1 = simple_strtoul(data+1, &data, 10);
-	if (data >= data_limit || *data != ',')
-		return 0;
-	p2 = simple_strtoul(data+1, &data, 10);
-	if (data >= data_limit || *data != ',')
-		return 0;
-	p3 = simple_strtoul(data+1, &data, 10);
-	if (data >= data_limit || *data != ',')
-		return 0;
-	p4 = simple_strtoul(data+1, &data, 10);
-	if (data >= data_limit || *data != ',')
-		return 0;
-	p5 = simple_strtoul(data+1, &data, 10);
-	if (data >= data_limit || *data != ',')
-		return 0;
-	p6 = simple_strtoul(data+1, &data, 10);
-	if (data >= data_limit || *data != ')')
-		return 0;
-
-	to = (p1<<24) | (p2<<16) | (p3<<8) | p4;
-	port = (p5<<8) | p6;
-
-	/*
-	 * Now update or create an masquerade entry for it
-	 */
-	IP_MASQ_DEBUG(1-debug, "PASV response %lX:%X %X:%X detected\n", ntohl(ms->saddr), 0, to, port);
-
-	n_ms = ip_masq_out_get(iph->protocol,
-				 ms->saddr, 0,
-				 htonl(to), htons(port));
-	if (!n_ms) {
-		n_ms = ip_masq_new(IPPROTO_TCP,
-					maddr, 0,
-					ms->saddr, 0,
-					htonl(to), htons(port),
-					IP_MASQ_F_NO_SPORT);
-
-		if (n_ms==NULL)
-			return 0;
-		ip_masq_control_add(n_ms, ms);
-	}
-
-#if 0	/* v0.12 state processing */
-
-	/*
-	 * keep for a bit longer than tcp_fin, client may not issue open
-	 * to server port before tcp_fin_timeout.
-	 */
-	n_ms->timeout = ip_masq_expire->tcp_fin_timeout*3;
-#endif
-	ms->app_data = NULL;
-	ip_masq_put(n_ms);
-
-	return 0;	/* no diff required for incoming packets, thank goodness */
-}
-
-struct ip_masq_app ip_masq_ftp = {
-        NULL,			/* next */
-	"ftp",			/* name */
-        0,                      /* type */
-        0,                      /* n_attach */
-        masq_ftp_init_1,        /* ip_masq_init_1 */
-        masq_ftp_done_1,        /* ip_masq_done_1 */
-        masq_ftp_out,           /* pkt_out */
-        masq_ftp_in,            /* pkt_in */
-};
-
-/*
- * 	ip_masq_ftp initialization
- */
-
-__initfunc(int ip_masq_ftp_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_ftp, 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, "Ftp: 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_ftp fin.
- */
-
-int ip_masq_ftp_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, "Ftp: unloaded support on port[%d] = %d\n",
-				       i, ports[i]);
-			}
-		}
-	}
-	return k;
-}
-
-#ifdef MODULE
-EXPORT_NO_SYMBOLS;
-
-int init_module(void)
-{
-        if (ip_masq_ftp_init() != 0)
-                return -EIO;
-        return 0;
-}
-
-void cleanup_module(void)
-{
-        if (ip_masq_ftp_done() != 0)
-                printk(KERN_INFO "ip_masq_ftp: can't remove module");
-}
-
-#endif /* MODULE */