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-rw-r--r--net/ipv4/ipvs/ip_vs_ftp.c400
1 files changed, 400 insertions, 0 deletions
diff --git a/net/ipv4/ipvs/ip_vs_ftp.c b/net/ipv4/ipvs/ip_vs_ftp.c
new file mode 100644
index 00000000000..a19a33ceb81
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+++ b/net/ipv4/ipvs/ip_vs_ftp.c
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+/*
+ * ip_vs_ftp.c: IPVS ftp application module
+ *
+ * Version: $Id: ip_vs_ftp.c,v 1.13 2002/09/15 08:14:08 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/module.h>
+#include <linux/moduleparam.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_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};
+module_param_array(ports, int, NULL, 0);
+
+/*
+ * Debug level
+ */
+#ifdef CONFIG_IP_VS_DEBUG
+static int debug=0;
+module_param(debug, int, 0);
+#endif
+
+
+/* Dummy variable */
+static int ip_vs_ftp_pasv;
+
+
+static int
+ip_vs_ftp_init_conn(struct ip_vs_app *app, struct ip_vs_conn *cp)
+{
+ return 0;
+}
+
+
+static int
+ip_vs_ftp_done_conn(struct ip_vs_app *app, 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 *app, struct ip_vs_conn *cp,
+ struct sk_buff **pskb, int *diff)
+{
+ 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 ret;
+
+ *diff = 0;
+
+ /* Only useful for established sessions */
+ if (cp->state != IP_VS_TCP_S_ESTABLISHED)
+ return 1;
+
+ /* Linear packets are much easier to deal with. */
+ if (!ip_vs_make_skb_writable(pskb, (*pskb)->len))
+ return 0;
+
+ if (cp->app_data == &ip_vs_ftp_pasv) {
+ iph = (*pskb)->nh.iph;
+ th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
+ data = (char *)th + (th->doff << 2);
+ data_limit = (*pskb)->tail;
+
+ if (ip_vs_ftp_get_addrport(data, data_limit,
+ SERVER_STRING,
+ sizeof(SERVER_STRING)-1, ')',
+ &from, &port,
+ &start, &end) != 1)
+ return 1;
+
+ 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);
+ }
+
+ /*
+ * 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);
+ ret = 1;
+ } else {
+ ret = !ip_vs_skb_replace(*pskb, GFP_ATOMIC, start,
+ end-start, buf, buf_len);
+ }
+
+ cp->app_data = NULL;
+ ip_vs_tcp_conn_listen(n_cp);
+ ip_vs_conn_put(n_cp);
+ return ret;
+ }
+ return 1;
+}
+
+
+/*
+ * 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 *app, struct ip_vs_conn *cp,
+ struct sk_buff **pskb, int *diff)
+{
+ 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;
+
+ /* no diff required for incoming packets */
+ *diff = 0;
+
+ /* Only useful for established sessions */
+ if (cp->state != IP_VS_TCP_S_ESTABLISHED)
+ return 1;
+
+ /* Linear packets are much easier to deal with. */
+ if (!ip_vs_make_skb_writable(pskb, (*pskb)->len))
+ return 0;
+
+ /*
+ * Detecting whether it is passive
+ */
+ iph = (*pskb)->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 = (*pskb)->tail;
+
+ while (data <= data_limit - 6) {
+ if (strnicmp(data, "PASV\r\n", 6) == 0) {
+ /* Passive mode on */
+ IP_VS_DBG(1-debug, "got PASV at %zd of %zd\n",
+ data - data_start,
+ data_limit - data_start);
+ cp->app_data = &ip_vs_ftp_pasv;
+ return 1;
+ }
+ 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 1;
+
+ IP_VS_DBG(1-debug, "PORT %u.%u.%u.%u:%d detected\n",
+ NIPQUAD(to), ntohs(port));
+
+ /* Passive mode off */
+ cp->app_data = NULL;
+
+ /*
+ * 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), 0);
+
+ 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);
+ }
+
+ /*
+ * Move tunnel to listen state
+ */
+ ip_vs_tcp_conn_listen(n_cp);
+ ip_vs_conn_put(n_cp);
+
+ return 1;
+}
+
+
+static struct ip_vs_app ip_vs_ftp = {
+ .name = "ftp",
+ .type = IP_VS_APP_TYPE_FTP,
+ .protocol = IPPROTO_TCP,
+ .module = THIS_MODULE,
+ .incs_list = LIST_HEAD_INIT(ip_vs_ftp.incs_list),
+ .init_conn = ip_vs_ftp_init_conn,
+ .done_conn = ip_vs_ftp_done_conn,
+ .bind_conn = NULL,
+ .unbind_conn = NULL,
+ .pkt_out = ip_vs_ftp_out,
+ .pkt_in = ip_vs_ftp_in,
+};
+
+
+/*
+ * ip_vs_ftp initialization
+ */
+static int __init ip_vs_ftp_init(void)
+{
+ int i, ret;
+ struct ip_vs_app *app = &ip_vs_ftp;
+
+ ret = register_ip_vs_app(app);
+ if (ret)
+ return ret;
+
+ for (i=0; i<IP_VS_APP_MAX_PORTS; i++) {
+ if (!ports[i])
+ continue;
+ ret = register_ip_vs_app_inc(app, app->protocol, ports[i]);
+ if (ret)
+ break;
+ IP_VS_DBG(1-debug, "%s: loaded support on port[%d] = %d\n",
+ app->name, i, ports[i]);
+ }
+
+ if (ret)
+ unregister_ip_vs_app(app);
+
+ return ret;
+}
+
+
+/*
+ * ip_vs_ftp finish.
+ */
+static void __exit ip_vs_ftp_exit(void)
+{
+ unregister_ip_vs_app(&ip_vs_ftp);
+}
+
+
+module_init(ip_vs_ftp_init);
+module_exit(ip_vs_ftp_exit);
+MODULE_LICENSE("GPL");
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