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

• Lines: 270
• Date: Sat Mar 30 13:20:34 1996
• Orig file: v1.3.80/linux/net/ipv4/ip_masq_irc.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.80/linux/net/ipv4/ip_masq_irc.c linux/net/ipv4/ip_masq_irc.c
@@ -0,0 +1,269 @@
+/*
+ *		IP_MASQ_IRC irc masquerading module
+ *
+ *
+ * Version:	@(#)ip_masq_irc.c 0.01   03/20/96
+ *
+ * Author:	Juan Jose Ciarlante
+ *		
+ *
+ * Fixes:
+ *	- set NO_DADDR flag in ip_masq_new().
+ *
+ * FIXME:
+ *	- detect also previous "PRIVMSG" string ?.
+ *
+ *	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 <linux/types.h>
+#include <linux/kernel.h>
+#include <asm/system.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_IRC 0
+
+static int
+masq_irc_init_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
+{
+        MOD_INC_USE_COUNT;
+        return 0;
+}
+
+static int
+masq_irc_done_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
+{
+        MOD_DEC_USE_COUNT;
+        return 0;
+}
+
+int
+masq_irc_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 *data, *data_limit;
+	__u32 s_addr;
+	__u16 s_port;
+	struct ip_masq *n_ms;
+	char buf[20];		/* "m_addr m_port" (dec base)*/
+        unsigned buf_len;
+	int diff;
+        int xtra_args = 0;      /* extra int args wanted after addr */
+        char *dcc_p, *addr_beg_p, *addr_end_p;
+
+        skb = *skb_p;
+	iph = skb->h.iph;
+        th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
+        data = (char *)&th[1];
+
+        /*
+         *	Hunt irc DCC string, the _shortest_:
+         *
+         *	strlen("DCC CHAT chat AAAAAAAA P\x01\n")=26
+         *	strlen("DCC SEND F AAAAAAAA P S\x01\n")=25
+         *		AAAAAAAAA: bound addr (1.0.0.0==16777216, min 8 digits)
+         *		P:         bound port (min 1 d )
+         *		F:         filename   (min 1 d )
+         *		S:         size       (min 1 d ) 
+         *		0x01, \n:  terminators
+         */
+
+        data_limit = skb->h.raw + skb->len;
+        
+	while (data < (data_limit - 25) )
+	{
+		if (memcmp(data,"DCC ",4))  {
+			data ++;
+			continue;
+		}
+                
+                dcc_p = data;
+		data += 4;     /* point to DCC cmd */
+                
+                if (memcmp(data, "CHAT ", 5) == 0 ||
+                    memcmp(data, "SEND ", 5) == 0)
+                {
+                        /*
+                         *	extra arg (file_size) req. for "SEND"
+                         */
+                        
+                        if (*data == 'S') xtra_args++;
+                        data += 5;
+                }
+                else
+                        continue;
+
+                /*
+                 *	skip next string.
+                 */
+                
+                while( *data++ != ' ')
+                        
+                        /*
+                         *	must still parse, at least, "AAAAAAAA P\x01\n",
+                         *      12 bytes left.
+                         */
+                        if (data > (data_limit-12)) return 0;
+
+                
+                addr_beg_p = data;
+                
+                /*
+                 *	client bound address in dec base
+                 */
+                
+ 		s_addr = simple_strtoul(data,&data,10);
+		if (*data++ !=' ')
+			continue;
+
+                /*
+                 *	client bound port in dec base
+                 */
+                
+		s_port = simple_strtoul(data,&data,10);
+                addr_end_p = data;
+                
+                /*
+                 *	should check args consistency?
+                 */
+                
+                while(xtra_args) {
+                        if (*data != ' ')
+                                break;
+                        data++;
+                        simple_strtoul(data,&data,10);
+                        xtra_args--;
+                }
+                
+                if (xtra_args != 0) continue;
+                
+                /*
+                 *	terminators.
+                 */
+                
+                if (data[0] != 0x01)
+                        continue;
+		if (data[1]!='\r' && data[1]!='\n')
+			continue;
+                
+		/*
+		 *	Now create an masquerade entry for it
+                 * 	must set NO_DPORT and NO_DADDR because
+                 *	connection is requested by another client.
+		 */
+                
+		n_ms = ip_masq_new(dev, IPPROTO_TCP,
+                                   htonl(s_addr),htons(s_port),
+                                   0, 0,
+                                   IP_MASQ_F_NO_DPORT|IP_MASQ_F_NO_DADDR
+                                   );
+		if (n_ms==NULL)
+			return 0;
+
+                ip_masq_set_expire(n_ms, MASQUERADE_EXPIRE_TCP_FIN);
+                
+		/*
+		 * Replace the old "address port" with the new one
+		 */
+                
+		buf_len = sprintf(buf,"%lu %u",
+                        ntohl(n_ms->maddr),ntohs(n_ms->mport));
+                
+		/*
+		 * Calculate required delta-offset to keep TCP happy
+		 */
+		
+		diff = buf_len - (addr_end_p-addr_beg_p);
+
+#if DEBUG_CONFIG_IP_MASQ_IRC
+                *addr_beg_p = '\0';
+		printk("masq_irc_out(): '%s' %X:%X detected (diff=%d)\n", dcc_p, s_addr,s_port, diff);
+#endif	
+		/*
+		 *	No shift.
+		 */
+		 
+		if (diff==0) 
+		{
+			/*
+			 * simple case, just copy.
+ 			 */
+ 			memcpy(addr_beg_p,buf,buf_len);
+ 			return 0;
+ 		}
+
+                *skb_p = ip_masq_skb_replace(skb, GFP_ATOMIC,
+                                             addr_beg_p, addr_end_p-addr_beg_p,
+                                             buf, buf_len);
+                return diff;
+	}
+	return 0;
+
+}
+
+/*
+ *	Main irc object
+ *     	You need 1 object per port in case you need
+ *	to offer also other used irc ports (6665,6666,etc),
+ *	they will share methods but they need own space for
+ *	data. 
+ */
+
+struct ip_masq_app ip_masq_irc = {
+        NULL,			/* next */
+        0,                      /* type */
+        0,                      /* n_attach */
+        masq_irc_init_1,        /* init_1 */
+        masq_irc_done_1,        /* done_1 */
+        masq_irc_out,           /* pkt_out */
+        NULL                    /* pkt_in */
+};
+
+/*
+ * 	ip_masq_irc initialization
+ */
+
+int ip_masq_irc_init(void)
+{
+        return register_ip_masq_app(&ip_masq_irc, IPPROTO_TCP, 6667);
+}
+
+/*
+ * 	ip_masq_irc fin.
+ */
+
+int ip_masq_irc_done(void)
+{
+        return unregister_ip_masq_app(&ip_masq_irc);
+}
+
+#ifdef MODULE
+
+int init_module(void)
+{
+        if (ip_masq_irc_init() != 0)
+                return -EIO;
+        register_symtab(NULL);
+        return 0;
+}
+
+void cleanup_module(void)
+{
+        if (ip_masq_irc_done() != 0)
+                printk("ip_masq_irc: can't remove module");
+}
+
+#endif /* MODULE */