[NETFILTER]: nf_conntrack/nf_nat: add amanda helper port
Patrick McHardy [Sun, 3 Dec 2006 06:08:26 +0000 (22:08 -0800)]
Add IPv4 and IPv6 capable nf_conntrack port of the Amanda conntrack/NAT helper.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter/nf_conntrack_amanda.h [new file with mode: 0644]
net/ipv4/netfilter/Kconfig
net/ipv4/netfilter/Makefile
net/ipv4/netfilter/nf_nat_amanda.c [new file with mode: 0644]
net/netfilter/Kconfig
net/netfilter/Makefile
net/netfilter/nf_conntrack_amanda.c [new file with mode: 0644]

diff --git a/include/linux/netfilter/nf_conntrack_amanda.h b/include/linux/netfilter/nf_conntrack_amanda.h
new file mode 100644 (file)
index 0000000..26c2235
--- /dev/null
@@ -0,0 +1,10 @@
+#ifndef _NF_CONNTRACK_AMANDA_H
+#define _NF_CONNTRACK_AMANDA_H
+/* AMANDA tracking. */
+
+extern unsigned int (*nf_nat_amanda_hook)(struct sk_buff **pskb,
+                                         enum ip_conntrack_info ctinfo,
+                                         unsigned int matchoff,
+                                         unsigned int matchlen,
+                                         struct nf_conntrack_expect *exp);
+#endif /* _NF_CONNTRACK_AMANDA_H */
index 52f876d..6993ec5 100644 (file)
@@ -512,6 +512,11 @@ config IP_NF_NAT_AMANDA
        default IP_NF_NAT if IP_NF_AMANDA=y
        default m if IP_NF_AMANDA=m
 
+config NF_NAT_AMANDA
+       tristate
+       depends on IP_NF_IPTABLES && NF_CONNTRACK && NF_NAT
+       default NF_NAT && NF_CONNTRACK_AMANDA
+
 config IP_NF_NAT_PPTP
        tristate
        depends on IP_NF_NAT!=n && IP_NF_PPTP!=n
index c0c6194..8893249 100644 (file)
@@ -50,6 +50,7 @@ obj-$(CONFIG_IP_NF_NAT_IRC) += ip_nat_irc.o
 obj-$(CONFIG_IP_NF_NAT_SIP) += ip_nat_sip.o
 
 # NAT helpers (nf_conntrack)
+obj-$(CONFIG_NF_NAT_AMANDA) += nf_nat_amanda.o
 obj-$(CONFIG_NF_NAT_FTP) += nf_nat_ftp.o
 
 # generic IP tables 
diff --git a/net/ipv4/netfilter/nf_nat_amanda.c b/net/ipv4/netfilter/nf_nat_amanda.c
new file mode 100644 (file)
index 0000000..0f17098
--- /dev/null
@@ -0,0 +1,78 @@
+/* Amanda extension for TCP NAT alteration.
+ * (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca>
+ * based on a copy of HW's ip_nat_irc.c as well as other modules
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/udp.h>
+
+#include <net/netfilter/nf_nat_helper.h>
+#include <net/netfilter/nf_nat_rule.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_expect.h>
+#include <linux/netfilter/nf_conntrack_amanda.h>
+
+MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>");
+MODULE_DESCRIPTION("Amanda NAT helper");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ip_nat_amanda");
+
+static unsigned int help(struct sk_buff **pskb,
+                        enum ip_conntrack_info ctinfo,
+                        unsigned int matchoff,
+                        unsigned int matchlen,
+                        struct nf_conntrack_expect *exp)
+{
+       char buffer[sizeof("65535")];
+       u_int16_t port;
+       unsigned int ret;
+
+       /* Connection comes from client. */
+       exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
+       exp->dir = IP_CT_DIR_ORIGINAL;
+
+       /* When you see the packet, we need to NAT it the same as the
+        * this one (ie. same IP: it will be TCP and master is UDP). */
+       exp->expectfn = nf_nat_follow_master;
+
+       /* Try to get same port: if not, try to change it. */
+       for (port = ntohs(exp->saved_proto.tcp.port); port != 0; port++) {
+               exp->tuple.dst.u.tcp.port = htons(port);
+               if (nf_conntrack_expect_related(exp) == 0)
+                       break;
+       }
+
+       if (port == 0)
+               return NF_DROP;
+
+       sprintf(buffer, "%u", port);
+       ret = nf_nat_mangle_udp_packet(pskb, exp->master, ctinfo,
+                                      matchoff, matchlen,
+                                      buffer, strlen(buffer));
+       if (ret != NF_ACCEPT)
+               nf_conntrack_unexpect_related(exp);
+       return ret;
+}
+
+static void __exit nf_nat_amanda_fini(void)
+{
+       rcu_assign_pointer(nf_nat_amanda_hook, NULL);
+       synchronize_rcu();
+}
+
+static int __init nf_nat_amanda_init(void)
+{
+       BUG_ON(rcu_dereference(nf_nat_amanda_hook));
+       rcu_assign_pointer(nf_nat_amanda_hook, help);
+       return 0;
+}
+
+module_init(nf_nat_amanda_init);
+module_exit(nf_nat_amanda_fini);
index efe56f7..f85fd43 100644 (file)
@@ -131,6 +131,21 @@ config NF_CT_PROTO_SCTP
          If you want to compile it as a module, say M here and read
          Documentation/modules.txt.  If unsure, say `N'.
 
+config NF_CONNTRACK_AMANDA
+       tristate "Amanda backup protocol support (EXPERIMENTAL)"
+       depends on EXPERIMENTAL && NF_CONNTRACK
+       select TEXTSEARCH
+       select TEXTSEARCH_KMP
+       help
+         If you are running the Amanda backup package <http://www.amanda.org/>
+         on this machine or machines that will be MASQUERADED through this
+         machine, then you may want to enable this feature.  This allows the
+         connection tracking and natting code to allow the sub-channels that
+         Amanda requires for communication of the backup data, messages and
+         index.
+
+         To compile it as a module, choose M here.  If unsure, say N.
+
 config NF_CONNTRACK_FTP
        tristate "FTP support on new connection tracking (EXPERIMENTAL)"
        depends on EXPERIMENTAL && NF_CONNTRACK
index 7f0089c..a5ee938 100644 (file)
@@ -20,6 +20,7 @@ obj-$(CONFIG_NF_CT_PROTO_SCTP) += nf_conntrack_proto_sctp.o
 obj-$(CONFIG_NF_CT_NETLINK) += nf_conntrack_netlink.o
 
 # connection tracking helpers
+obj-$(CONFIG_NF_CONNTRACK_AMANDA) += nf_conntrack_amanda.o
 obj-$(CONFIG_NF_CONNTRACK_FTP) += nf_conntrack_ftp.o
 
 # generic X tables 
diff --git a/net/netfilter/nf_conntrack_amanda.c b/net/netfilter/nf_conntrack_amanda.c
new file mode 100644 (file)
index 0000000..5c495dc
--- /dev/null
@@ -0,0 +1,237 @@
+/* Amanda extension for IP connection tracking
+ *
+ * (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca>
+ * based on HW's ip_conntrack_irc.c as well as other modules
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/textsearch.h>
+#include <linux/skbuff.h>
+#include <linux/in.h>
+#include <linux/udp.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_expect.h>
+#include <net/netfilter/nf_conntrack_ecache.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <linux/netfilter/nf_conntrack_amanda.h>
+
+static unsigned int master_timeout __read_mostly = 300;
+static char *ts_algo = "kmp";
+
+MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>");
+MODULE_DESCRIPTION("Amanda connection tracking module");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ip_conntrack_amanda");
+
+module_param(master_timeout, uint, 0600);
+MODULE_PARM_DESC(master_timeout, "timeout for the master connection");
+module_param(ts_algo, charp, 0400);
+MODULE_PARM_DESC(ts_algo, "textsearch algorithm to use (default kmp)");
+
+unsigned int (*nf_nat_amanda_hook)(struct sk_buff **pskb,
+                                  enum ip_conntrack_info ctinfo,
+                                  unsigned int matchoff,
+                                  unsigned int matchlen,
+                                  struct nf_conntrack_expect *exp)
+                                  __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_amanda_hook);
+
+enum amanda_strings {
+       SEARCH_CONNECT,
+       SEARCH_NEWLINE,
+       SEARCH_DATA,
+       SEARCH_MESG,
+       SEARCH_INDEX,
+};
+
+static struct {
+       char                    *string;
+       size_t                  len;
+       struct ts_config        *ts;
+} search[] __read_mostly = {
+       [SEARCH_CONNECT] = {
+               .string = "CONNECT ",
+               .len    = 8,
+       },
+       [SEARCH_NEWLINE] = {
+               .string = "\n",
+               .len    = 1,
+       },
+       [SEARCH_DATA] = {
+               .string = "DATA ",
+               .len    = 5,
+       },
+       [SEARCH_MESG] = {
+               .string = "MESG ",
+               .len    = 5,
+       },
+       [SEARCH_INDEX] = {
+               .string = "INDEX ",
+               .len    = 6,
+       },
+};
+
+static int amanda_help(struct sk_buff **pskb,
+                      unsigned int protoff,
+                      struct nf_conn *ct,
+                      enum ip_conntrack_info ctinfo)
+{
+       struct ts_state ts;
+       struct nf_conntrack_expect *exp;
+       struct nf_conntrack_tuple *tuple;
+       unsigned int dataoff, start, stop, off, i;
+       char pbuf[sizeof("65535")], *tmp;
+       u_int16_t len;
+       __be16 port;
+       int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
+       int ret = NF_ACCEPT;
+       typeof(nf_nat_amanda_hook) nf_nat_amanda;
+
+       /* Only look at packets from the Amanda server */
+       if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
+               return NF_ACCEPT;
+
+       /* increase the UDP timeout of the master connection as replies from
+        * Amanda clients to the server can be quite delayed */
+       nf_ct_refresh(ct, *pskb, master_timeout * HZ);
+
+       /* No data? */
+       dataoff = protoff + sizeof(struct udphdr);
+       if (dataoff >= (*pskb)->len) {
+               if (net_ratelimit())
+                       printk("amanda_help: skblen = %u\n", (*pskb)->len);
+               return NF_ACCEPT;
+       }
+
+       memset(&ts, 0, sizeof(ts));
+       start = skb_find_text(*pskb, dataoff, (*pskb)->len,
+                             search[SEARCH_CONNECT].ts, &ts);
+       if (start == UINT_MAX)
+               goto out;
+       start += dataoff + search[SEARCH_CONNECT].len;
+
+       memset(&ts, 0, sizeof(ts));
+       stop = skb_find_text(*pskb, start, (*pskb)->len,
+                            search[SEARCH_NEWLINE].ts, &ts);
+       if (stop == UINT_MAX)
+               goto out;
+       stop += start;
+
+       for (i = SEARCH_DATA; i <= SEARCH_INDEX; i++) {
+               memset(&ts, 0, sizeof(ts));
+               off = skb_find_text(*pskb, start, stop, search[i].ts, &ts);
+               if (off == UINT_MAX)
+                       continue;
+               off += start + search[i].len;
+
+               len = min_t(unsigned int, sizeof(pbuf) - 1, stop - off);
+               if (skb_copy_bits(*pskb, off, pbuf, len))
+                       break;
+               pbuf[len] = '\0';
+
+               port = htons(simple_strtoul(pbuf, &tmp, 10));
+               len = tmp - pbuf;
+               if (port == 0 || len > 5)
+                       break;
+
+               exp = nf_conntrack_expect_alloc(ct);
+               if (exp == NULL) {
+                       ret = NF_DROP;
+                       goto out;
+               }
+               tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
+               nf_conntrack_expect_init(exp, family,
+                                        &tuple->src.u3, &tuple->dst.u3,
+                                        IPPROTO_TCP, NULL, &port);
+
+               nf_nat_amanda = rcu_dereference(nf_nat_amanda_hook);
+               if (nf_nat_amanda && ct->status & IPS_NAT_MASK)
+                       ret = nf_nat_amanda(pskb, ctinfo, off - dataoff,
+                                           len, exp);
+               else if (nf_conntrack_expect_related(exp) != 0)
+                       ret = NF_DROP;
+               nf_conntrack_expect_put(exp);
+       }
+
+out:
+       return ret;
+}
+
+static struct nf_conntrack_helper amanda_helper[2] __read_mostly = {
+       {
+               .name                   = "amanda",
+               .max_expected           = 3,
+               .timeout                = 180,
+               .me                     = THIS_MODULE,
+               .help                   = amanda_help,
+               .tuple.src.l3num        = AF_INET,
+               .tuple.src.u.udp.port   = __constant_htons(10080),
+               .tuple.dst.protonum     = IPPROTO_UDP,
+               .mask.src.l3num         = 0xFFFF,
+               .mask.src.u.udp.port    = __constant_htons(0xFFFF),
+               .mask.dst.protonum      = 0xFF,
+       },
+       {
+               .name                   = "amanda",
+               .max_expected           = 3,
+               .timeout                = 180,
+               .me                     = THIS_MODULE,
+               .help                   = amanda_help,
+               .tuple.src.l3num        = AF_INET6,
+               .tuple.src.u.udp.port   = __constant_htons(10080),
+               .tuple.dst.protonum     = IPPROTO_UDP,
+               .mask.src.l3num         = 0xFFFF,
+               .mask.src.u.udp.port    = __constant_htons(0xFFFF),
+               .mask.dst.protonum      = 0xFF,
+       },
+};
+
+static void __exit nf_conntrack_amanda_fini(void)
+{
+       int i;
+
+       nf_conntrack_helper_unregister(&amanda_helper[0]);
+       nf_conntrack_helper_unregister(&amanda_helper[1]);
+       for (i = 0; i < ARRAY_SIZE(search); i++)
+               textsearch_destroy(search[i].ts);
+}
+
+static int __init nf_conntrack_amanda_init(void)
+{
+       int ret, i;
+
+       ret = -ENOMEM;
+       for (i = 0; i < ARRAY_SIZE(search); i++) {
+               search[i].ts = textsearch_prepare(ts_algo, search[i].string,
+                                                 search[i].len,
+                                                 GFP_KERNEL, TS_AUTOLOAD);
+               if (search[i].ts == NULL)
+                       goto err1;
+       }
+       ret = nf_conntrack_helper_register(&amanda_helper[0]);
+       if (ret < 0)
+               goto err1;
+       ret = nf_conntrack_helper_register(&amanda_helper[1]);
+       if (ret < 0)
+               goto err2;
+       return 0;
+
+err2:
+       nf_conntrack_helper_unregister(&amanda_helper[0]);
+err1:
+       for (; i >= 0; i--) {
+               if (search[i].ts)
+                       textsearch_destroy(search[i].ts);
+       }
+       return ret;
+}
+
+module_init(nf_conntrack_amanda_init);
+module_exit(nf_conntrack_amanda_fini);