patch-1.3.81 linux/net/ipv4/ip_masq_ftp.c

• Lines: 199
• Date: Sat Mar 30 13:20:34 1996
• Orig file: v1.3.80/linux/net/ipv4/ip_masq_ftp.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.80/linux/net/ipv4/ip_masq_ftp.c linux/net/ipv4/ip_masq_ftp.c
@@ -0,0 +1,198 @@
+/*
+ *		IP_MASQ_FTP ftp masquerading module
+ *
+ *
+ * Version:	@(#)ip_masq_ftp.c 0.01   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
+ *	
+ *
+ *
+ *	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.
+ *	
+ */
+
+#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 <net/protocol.h>
+#include <net/tcp.h>
+#include <net/ip_masq.h>
+
+#define DEBUG_CONFIG_IP_MASQ_FTP 0
+
+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, struct device *dev)
+{
+        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->h.iph;
+        th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
+        data = (char *)&th[1];
+        
+        data_limit = skb->h.raw + skb->len - 18;
+
+	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;
+#if DEBUG_CONFIG_IP_MASQ_FTP
+		printk("PORT %lX:%X detected\n",from,port);
+#endif	
+		/*
+		 * Now create an masquerade entry for it
+		 */
+                n_ms = ip_masq_new(dev, IPPROTO_TCP,
+                                   htonl(from), htons(port),
+                                   iph->daddr, 0,
+                                   IP_MASQ_F_NO_DPORT);
+                                   
+		if (n_ms==NULL)
+			return 0;
+
+                ip_masq_set_expire(n_ms, MASQUERADE_EXPIRE_TCP_FIN);
+                
+		/*
+		 * 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);
+ 
+		/*
+		 * 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);
+ 			return 0;
+ 		}
+
+                *skb_p = ip_masq_skb_replace(skb, GFP_ATOMIC, p, data-p, buf, buf_len);
+                return diff;
+
+	}
+	return 0;
+
+}
+
+struct ip_masq_app ip_masq_ftp = {
+        NULL,			/* next */
+        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 */
+        NULL                    /* pkt_in */
+};
+
+/*
+ * 	ip_masq_ftp initialization
+ */
+
+int ip_masq_ftp_init(void)
+{
+        return register_ip_masq_app(&ip_masq_ftp, IPPROTO_TCP, 21);
+}
+
+/*
+ * 	ip_masq_ftp fin.
+ */
+
+int ip_masq_ftp_done(void)
+{
+        return unregister_ip_masq_app(&ip_masq_ftp);
+}
+
+#ifdef MODULE
+
+int init_module(void)
+{
+        if (ip_masq_ftp_init() != 0)
+                return -EIO;
+        register_symtab(0);
+        return 0;
+}
+
+void cleanup_module(void)
+{
+        if (ip_masq_ftp_done() != 0)
+                printk("ip_masq_ftp: can't remove module");
+}
+
+#endif /* MODULE */