patch-2.4.23 linux-2.4.23/net/ipv4/ipvs/ip_vs_ftp.c

• Lines: 413
• Date: 2003-11-28 10:26:21.000000000 -0800
• Orig file: linux-2.4.22/net/ipv4/ipvs/ip_vs_ftp.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.22/net/ipv4/ipvs/ip_vs_ftp.c linux-2.4.23/net/ipv4/ipvs/ip_vs_ftp.c
@@ -0,0 +1,412 @@
+/*
+ * IP_VS        ftp application module
+ *
+ * Version:	$Id: ip_vs_ftp.c,v 1.12 2002/08/10 04:32:35 wensong Exp $
+ *
+ * Authors:	Wensong Zhang <wensong@linuxvirtualserver.org>
+ *
+ * Changes:
+ *
+ *
+ *	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.
+ *
+ * Most code here is taken from ip_masq_ftp.c in kernel 2.2. The difference
+ * is that ip_vs_ftp module handles the reverse direction to ip_masq_ftp.
+ *
+ *		IP_MASQ_FTP ftp masquerading module
+ *
+ * Version:	@(#)ip_masq_ftp.c 0.04   02/05/96
+ *
+ * Author:	Wouter Gadeyne
+ *
+ */
+
+#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>
+
+#include <net/ip_vs.h>
+
+
+#define SERVER_STRING "227 Entering Passive Mode ("
+#define CLIENT_STRING "PORT "
+
+
+/*
+ * List of ports (up to IP_VS_APP_MAX_PORTS) to be handled by helper
+ * First port is set to the default port.
+ */
+static int ports[IP_VS_APP_MAX_PORTS] = {21, 0};
+struct ip_vs_app *incarnations[IP_VS_APP_MAX_PORTS];
+
+/*
+ *	Debug level
+ */
+#ifdef CONFIG_IP_VS_DEBUG
+static int debug=0;
+MODULE_PARM(debug, "i");
+#endif
+
+MODULE_PARM(ports, "1-" __MODULE_STRING(IP_VS_APP_MAX_PORTS) "i");
+
+/*	Dummy variable */
+static int ip_vs_ftp_pasv;
+
+
+static int
+ip_vs_ftp_init_conn(struct ip_vs_app *vapp, struct ip_vs_conn *cp)
+{
+	return 0;
+}
+
+
+static int
+ip_vs_ftp_done_conn(struct ip_vs_app *vapp, struct ip_vs_conn *cp)
+{
+	return 0;
+}
+
+
+/*
+ * Get <addr,port> from the string "xxx.xxx.xxx.xxx,ppp,ppp", started
+ * with the "pattern" and terminated with the "term" character.
+ * <addr,port> is in network order.
+ */
+static int ip_vs_ftp_get_addrport(char *data, char *data_limit,
+				  const char *pattern, size_t plen, char term,
+				  __u32 *addr, __u16 *port,
+				  char **start, char **end)
+{
+	unsigned char p[6];
+	int i = 0;
+
+	if (data_limit - data < plen) {
+		/* check if there is partial match */
+		if (strnicmp(data, pattern, data_limit - data) == 0)
+			return -1;
+		else
+			return 0;
+	}
+
+	if (strnicmp(data, pattern, plen) != 0) {
+		return 0;
+	}
+	*start = data + plen;
+
+	for (data = *start; *data != term; data++) {
+		if (data == data_limit)
+			return -1;
+	}
+	*end = data;
+
+	memset(p, 0, sizeof(p));
+	for (data = *start; data != *end; data++) {
+		if (*data >= '0' && *data <= '9') {
+			p[i] = p[i]*10 + *data - '0';
+		} else if (*data == ',' && i < 5) {
+			i++;
+		} else {
+			/* unexpected character */
+			return -1;
+		}
+	}
+
+	if (i != 5)
+		return -1;
+
+	*addr = (p[3]<<24) | (p[2]<<16) | (p[1]<<8) | p[0];
+	*port = (p[5]<<8) | p[4];
+	return 1;
+}
+
+
+/*
+ * Look at outgoing ftp packets to catch the response to a PASV command
+ * from the server (inside-to-outside).
+ * When we see one, we build a connection entry with the client address,
+ * client port 0 (unknown at the moment), the server address and the
+ * server port.  Mark the current connection entry as a control channel
+ * of the new entry. All this work is just to make the data connection
+ * can be scheduled to the right server later.
+ *
+ * The outgoing 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.
+ */
+static int ip_vs_ftp_out(struct ip_vs_app *vapp,
+			 struct ip_vs_conn *cp, struct sk_buff *skb)
+{
+	struct iphdr *iph;
+	struct tcphdr *th;
+	char *data, *data_limit;
+	char *start, *end;
+	__u32 from;
+	__u16 port;
+	struct ip_vs_conn *n_cp;
+	char buf[24];		/* xxx.xxx.xxx.xxx,ppp,ppp\000 */
+	unsigned buf_len;
+	int diff;
+
+	/* Only useful for established sessions */
+	if (cp->state != IP_VS_S_ESTABLISHED)
+		return 0;
+
+	if (cp->app_data == &ip_vs_ftp_pasv) {
+		iph = skb->nh.iph;
+		th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
+		data = (char *)th + (th->doff << 2);
+		data_limit = skb->tail;
+
+		if (ip_vs_ftp_get_addrport(data, data_limit,
+					   SERVER_STRING,
+					   sizeof(SERVER_STRING)-1, ')',
+					   &from, &port,
+					   &start, &end) != 1)
+			return 0;
+
+		IP_VS_DBG(1-debug, "PASV response (%u.%u.%u.%u:%d) -> "
+			  "%u.%u.%u.%u:%d detected\n",
+			  NIPQUAD(from), ntohs(port), NIPQUAD(cp->caddr), 0);
+
+		/*
+		 * Now update or create an connection entry for it
+		 */
+		n_cp = ip_vs_conn_out_get(iph->protocol, from, port,
+					  cp->caddr, 0);
+		if (!n_cp) {
+			n_cp = ip_vs_conn_new(IPPROTO_TCP,
+					      cp->caddr, 0,
+					      cp->vaddr, port,
+					      from, port,
+					      IP_VS_CONN_F_NO_CPORT,
+					      cp->dest);
+			if (!n_cp)
+				return 0;
+
+			/* add its controller */
+			ip_vs_control_add(n_cp, cp);
+
+			/* increase dest's inactive connection counter */
+			if (cp->dest)
+				atomic_inc(&cp->dest->inactconns);
+		}
+
+		/*
+		 * Replace the old passive address with the new one
+		 */
+		from = n_cp->vaddr;
+		port = n_cp->vport;
+		sprintf(buf,"%d,%d,%d,%d,%d,%d", NIPQUAD(from),
+			port&255, port>>8&255);
+		buf_len = strlen(buf);
+
+		/*
+		 * Calculate required delta-offset to keep TCP happy
+		 */
+		diff = buf_len - (end-start);
+
+		if (diff == 0) {
+			/* simply replace it with new passive address */
+			memcpy(start, buf, buf_len);
+		} else {
+			/* fixme: return value isn't checked here */
+			ip_vs_skb_replace(skb, GFP_ATOMIC, start,
+					  end-start, buf, buf_len);
+		}
+
+		cp->app_data = NULL;
+		ip_vs_conn_listen(n_cp);
+		ip_vs_conn_put(n_cp);
+		return diff;
+	}
+	return 0;
+}
+
+
+/*
+ * Look at incoming ftp packets to catch the PASV/PORT command
+ * (outside-to-inside).
+ *
+ * The incoming packet having the PORT command should be something like
+ *      "PORT xxx,xxx,xxx,xxx,ppp,ppp\n".
+ * xxx,xxx,xxx,xxx is the client address, ppp,ppp is the client port number.
+ * In this case, we create a connection entry using the client address and
+ * port, so that the active ftp data connection from the server can reach
+ * the client.
+ */
+static int ip_vs_ftp_in(struct ip_vs_app *vapp,
+			struct ip_vs_conn *cp, struct sk_buff *skb)
+{
+	struct iphdr *iph;
+	struct tcphdr *th;
+	char *data, *data_start, *data_limit;
+	char *start, *end;
+	__u32 to;
+	__u16 port;
+	struct ip_vs_conn *n_cp;
+
+	/* Only useful for established sessions */
+	if (cp->state != IP_VS_S_ESTABLISHED)
+		return 0;
+
+	/*
+	 * Detecting whether it is passive
+	 */
+	iph = skb->nh.iph;
+	th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
+
+	/* Since there may be OPTIONS in the TCP packet and the HLEN is
+	   the length of the header in 32-bit multiples, it is accurate
+	   to calculate data address by th+HLEN*4 */
+	data = data_start = (char *)th + (th->doff << 2);
+	data_limit = skb->tail;
+
+	while (data <= data_limit - 6) {
+		if (strnicmp(data, "PASV\r\n", 6) == 0) {
+			IP_VS_DBG(1-debug, "got PASV at %d of %d\n",
+				  data - data_start,
+				  data_limit - data_start);
+			cp->app_data = &ip_vs_ftp_pasv;
+			return 0;
+		}
+		data++;
+	}
+
+	/*
+	 * To support virtual FTP server, the scenerio is as follows:
+	 *       FTP client ----> Load Balancer ----> FTP server
+	 * First detect the port number in the application data,
+	 * then create a new connection entry for the coming data
+	 * connection.
+	 */
+	if (ip_vs_ftp_get_addrport(data_start, data_limit,
+				   CLIENT_STRING, sizeof(CLIENT_STRING)-1,
+				   '\r', &to, &port,
+				   &start, &end) != 1)
+		return 0;
+
+	IP_VS_DBG(1-debug, "PORT %u.%u.%u.%u:%d detected\n",
+		  NIPQUAD(to), ntohs(port));
+
+	/*
+	 * Now update or create a connection entry for it
+	 */
+	IP_VS_DBG(1-debug, "protocol %s %u.%u.%u.%u:%d %u.%u.%u.%u:%d\n",
+		  ip_vs_proto_name(iph->protocol),
+		  NIPQUAD(to), ntohs(port),
+		  NIPQUAD(cp->vaddr), ntohs(cp->vport) - 1);
+
+	n_cp = ip_vs_conn_in_get(iph->protocol,
+				 to, port,
+				 cp->vaddr, htons(ntohs(cp->vport)-1));
+	if (!n_cp) {
+		n_cp = ip_vs_conn_new(IPPROTO_TCP,
+				      to, port,
+				      cp->vaddr, htons(ntohs(cp->vport)-1),
+				      cp->daddr, htons(ntohs(cp->dport)-1),
+				      0,
+				      cp->dest);
+		if (!n_cp)
+			return 0;
+
+		/* add its controller */
+		ip_vs_control_add(n_cp, cp);
+
+		/* increase dest's inactive connection counter */
+		if (cp->dest)
+			atomic_inc(&cp->dest->inactconns);
+	}
+
+	/*
+	 *	Move tunnel to listen state
+	 */
+	ip_vs_conn_listen(n_cp);
+	ip_vs_conn_put(n_cp);
+
+	/* no diff required for incoming packets */
+	return 0;
+}
+
+
+static struct ip_vs_app ip_vs_ftp = {
+	{0},			/* n_list */
+	"ftp",			/* name */
+	0,                      /* type */
+	THIS_MODULE,            /* this module */
+	ip_vs_ftp_init_conn,    /* ip_vs_init_conn */
+	ip_vs_ftp_done_conn,    /* ip_vs_done_conn */
+	ip_vs_ftp_out,          /* pkt_out */
+	ip_vs_ftp_in,           /* pkt_in */
+};
+
+
+/*
+ *	ip_vs_ftp initialization
+ */
+static int __init ip_vs_ftp_init(void)
+{
+	int i, j;
+
+	for (i=0; i<IP_VS_APP_MAX_PORTS; i++) {
+		if (ports[i]) {
+			if (!(incarnations[i] =
+			     kmalloc(sizeof(struct ip_vs_app), GFP_KERNEL)))
+				return -ENOMEM;
+
+			memcpy(incarnations[i], &ip_vs_ftp,
+			       sizeof(struct ip_vs_app));
+			if ((j = register_ip_vs_app(incarnations[i],
+						    IPPROTO_TCP,
+						    ports[i]))) {
+				return j;
+			}
+			IP_VS_DBG(1-debug,
+				  "Ftp: loaded support on port[%d] = %d\n",
+				  i, ports[i]);
+		} else {
+			/* To be safe, force the incarnation table entry
+			   to be NULL */
+			incarnations[i] = NULL;
+		}
+	}
+	return 0;
+}
+
+
+/*
+ *	ip_vs_ftp finish.
+ */
+static void __exit ip_vs_ftp_exit(void)
+{
+	int i, j, k;
+
+	k=0;
+	for (i=0; i<IP_VS_APP_MAX_PORTS; i++) {
+		if (incarnations[i]) {
+			if ((j = unregister_ip_vs_app(incarnations[i]))) {
+				k = j;
+			} else {
+				kfree(incarnations[i]);
+				incarnations[i] = NULL;
+				IP_VS_DBG(1-debug, "Ftp: unloaded support on port[%d] = %d\n",
+					  i, ports[i]);
+			}
+		}
+	}
+}
+
+
+module_init(ip_vs_ftp_init);
+module_exit(ip_vs_ftp_exit);
+MODULE_LICENSE("GPL");