[NETFILTER]: nf_conntrack/nf_nat: add TFTP helper port
Add IPv4 and IPv6 capable nf_conntrack port of the TFTP conntrack/NAT helper.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netfilter/nf_conntrack_tftp.h b/include/linux/netfilter/nf_conntrack_tftp.h
new file mode 100644
index 0000000..0d79b7a
--- /dev/null
+++ b/include/linux/netfilter/nf_conntrack_tftp.h
@@ -0,0 +1,20 @@
+#ifndef _NF_CONNTRACK_TFTP_H
+#define _NF_CONNTRACK_TFTP_H
+
+#define TFTP_PORT 69
+
+struct tftphdr {
+ __be16 opcode;
+};
+
+#define TFTP_OPCODE_READ 1
+#define TFTP_OPCODE_WRITE 2
+#define TFTP_OPCODE_DATA 3
+#define TFTP_OPCODE_ACK 4
+#define TFTP_OPCODE_ERROR 5
+
+extern unsigned int (*nf_nat_tftp_hook)(struct sk_buff **pskb,
+ enum ip_conntrack_info ctinfo,
+ struct nf_conntrack_expect *exp);
+
+#endif /* _NF_CONNTRACK_TFTP_H */
diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 83e83f5..1c0018b 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -515,6 +515,11 @@
default IP_NF_NAT if IP_NF_TFTP=y
default m if IP_NF_TFTP=m
+config NF_NAT_TFTP
+ tristate
+ depends on IP_NF_IPTABLES && NF_CONNTRACK && NF_NAT
+ default NF_NAT && NF_CONNTRACK_TFTP
+
config IP_NF_NAT_AMANDA
tristate
depends on IP_NF_IPTABLES!=n && IP_NF_CONNTRACK!=n && IP_NF_NAT!=n
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index 167b65e..3ca0af0e 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -56,6 +56,7 @@
obj-$(CONFIG_NF_NAT_IRC) += nf_nat_irc.o
obj-$(CONFIG_NF_NAT_PPTP) += nf_nat_pptp.o
obj-$(CONFIG_NF_NAT_SIP) += nf_nat_sip.o
+obj-$(CONFIG_NF_NAT_TFTP) += nf_nat_tftp.o
# NAT protocols (nf_nat)
obj-$(CONFIG_NF_NAT_PROTO_GRE) += nf_nat_proto_gre.o
diff --git a/net/ipv4/netfilter/nf_nat_tftp.c b/net/ipv4/netfilter/nf_nat_tftp.c
new file mode 100644
index 0000000..2566b79
--- /dev/null
+++ b/net/ipv4/netfilter/nf_nat_tftp.c
@@ -0,0 +1,52 @@
+/* (C) 2001-2002 Magnus Boden <mb@ozaba.mine.nu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.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_tftp.h>
+
+MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");
+MODULE_DESCRIPTION("TFTP NAT helper");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ip_nat_tftp");
+
+static unsigned int help(struct sk_buff **pskb,
+ enum ip_conntrack_info ctinfo,
+ struct nf_conntrack_expect *exp)
+{
+ struct nf_conn *ct = exp->master;
+
+ exp->saved_proto.udp.port
+ = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port;
+ exp->dir = IP_CT_DIR_REPLY;
+ exp->expectfn = nf_nat_follow_master;
+ if (nf_conntrack_expect_related(exp) != 0)
+ return NF_DROP;
+ return NF_ACCEPT;
+}
+
+static void __exit nf_nat_tftp_fini(void)
+{
+ rcu_assign_pointer(nf_nat_tftp_hook, NULL);
+ synchronize_rcu();
+}
+
+static int __init nf_nat_tftp_init(void)
+{
+ BUG_ON(rcu_dereference(nf_nat_tftp_hook));
+ rcu_assign_pointer(nf_nat_tftp_hook, help);
+ return 0;
+}
+
+module_init(nf_nat_tftp_init);
+module_exit(nf_nat_tftp_fini);
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index e738911..e0deac1 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -248,6 +248,17 @@
To compile it as a module, choose M here. If unsure, say N.
+config NF_CONNTRACK_TFTP
+ tristate "TFTP protocol support (EXPERIMENTAL)"
+ depends on EXPERIMENTAL && NF_CONNTRACK
+ help
+ TFTP connection tracking helper, this is required depending
+ on how restrictive your ruleset is.
+ If you are using a tftp client behind -j SNAT or -j MASQUERADING
+ you will need this.
+
+ To compile it as a module, choose M here. If unsure, say N.
+
config NF_CT_NETLINK
tristate 'Connection tracking netlink interface (EXPERIMENTAL)'
depends on EXPERIMENTAL && NF_CONNTRACK && NETFILTER_NETLINK
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 86da217..5dc5574 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -30,6 +30,7 @@
obj-$(CONFIG_NF_CONNTRACK_NETBIOS_NS) += nf_conntrack_netbios_ns.o
obj-$(CONFIG_NF_CONNTRACK_PPTP) += nf_conntrack_pptp.o
obj-$(CONFIG_NF_CONNTRACK_SIP) += nf_conntrack_sip.o
+obj-$(CONFIG_NF_CONNTRACK_TFTP) += nf_conntrack_tftp.o
# generic X tables
obj-$(CONFIG_NETFILTER_XTABLES) += x_tables.o xt_tcpudp.o
diff --git a/net/netfilter/nf_conntrack_tftp.c b/net/netfilter/nf_conntrack_tftp.c
new file mode 100644
index 0000000..d46a126
--- /dev/null
+++ b/net/netfilter/nf_conntrack_tftp.c
@@ -0,0 +1,159 @@
+/* (C) 2001-2002 Magnus Boden <mb@ozaba.mine.nu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/in.h>
+#include <linux/udp.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_tuple.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_tftp.h>
+
+MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");
+MODULE_DESCRIPTION("TFTP connection tracking helper");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ip_conntrack_tftp");
+
+#define MAX_PORTS 8
+static unsigned short ports[MAX_PORTS];
+static int ports_c;
+module_param_array(ports, ushort, &ports_c, 0400);
+MODULE_PARM_DESC(ports, "Port numbers of TFTP servers");
+
+#if 0
+#define DEBUGP(format, args...) printk("%s:%s:" format, \
+ __FILE__, __FUNCTION__ , ## args)
+#else
+#define DEBUGP(format, args...)
+#endif
+
+unsigned int (*nf_nat_tftp_hook)(struct sk_buff **pskb,
+ enum ip_conntrack_info ctinfo,
+ struct nf_conntrack_expect *exp) __read_mostly;
+EXPORT_SYMBOL_GPL(nf_nat_tftp_hook);
+
+static int tftp_help(struct sk_buff **pskb,
+ unsigned int protoff,
+ struct nf_conn *ct,
+ enum ip_conntrack_info ctinfo)
+{
+ struct tftphdr _tftph, *tfh;
+ struct nf_conntrack_expect *exp;
+ struct nf_conntrack_tuple *tuple;
+ unsigned int ret = NF_ACCEPT;
+ int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
+ typeof(nf_nat_tftp_hook) nf_nat_tftp;
+
+ tfh = skb_header_pointer(*pskb, protoff + sizeof(struct udphdr),
+ sizeof(_tftph), &_tftph);
+ if (tfh == NULL)
+ return NF_ACCEPT;
+
+ switch (ntohs(tfh->opcode)) {
+ case TFTP_OPCODE_READ:
+ case TFTP_OPCODE_WRITE:
+ /* RRQ and WRQ works the same way */
+ DEBUGP("");
+ NF_CT_DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
+ NF_CT_DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
+
+ exp = nf_conntrack_expect_alloc(ct);
+ if (exp == NULL)
+ return NF_DROP;
+ tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
+ nf_conntrack_expect_init(exp, family,
+ &tuple->src.u3, &tuple->dst.u3,
+ IPPROTO_UDP,
+ NULL, &tuple->dst.u.udp.port);
+
+ DEBUGP("expect: ");
+ NF_CT_DUMP_TUPLE(&exp->tuple);
+ NF_CT_DUMP_TUPLE(&exp->mask);
+
+ nf_nat_tftp = rcu_dereference(nf_nat_tftp_hook);
+ if (nf_nat_tftp && ct->status & IPS_NAT_MASK)
+ ret = nf_nat_tftp(pskb, ctinfo, exp);
+ else if (nf_conntrack_expect_related(exp) != 0)
+ ret = NF_DROP;
+ nf_conntrack_expect_put(exp);
+ break;
+ case TFTP_OPCODE_DATA:
+ case TFTP_OPCODE_ACK:
+ DEBUGP("Data/ACK opcode\n");
+ break;
+ case TFTP_OPCODE_ERROR:
+ DEBUGP("Error opcode\n");
+ break;
+ default:
+ DEBUGP("Unknown opcode\n");
+ }
+ return ret;
+}
+
+static struct nf_conntrack_helper tftp[MAX_PORTS][2] __read_mostly;
+static char tftp_names[MAX_PORTS][2][sizeof("tftp-65535")] __read_mostly;
+
+static void nf_conntrack_tftp_fini(void)
+{
+ int i, j;
+
+ for (i = 0; i < ports_c; i++) {
+ for (j = 0; j < 2; j++)
+ nf_conntrack_helper_unregister(&tftp[i][j]);
+ }
+}
+
+static int __init nf_conntrack_tftp_init(void)
+{
+ int i, j, ret;
+ char *tmpname;
+
+ if (ports_c == 0)
+ ports[ports_c++] = TFTP_PORT;
+
+ for (i = 0; i < ports_c; i++) {
+ memset(&tftp[i], 0, sizeof(tftp[i]));
+
+ tftp[i][0].tuple.src.l3num = AF_INET;
+ tftp[i][1].tuple.src.l3num = AF_INET6;
+ for (j = 0; j < 2; j++) {
+ tftp[i][j].tuple.dst.protonum = IPPROTO_UDP;
+ tftp[i][j].tuple.src.u.udp.port = htons(ports[i]);
+ tftp[i][j].mask.src.l3num = 0xFFFF;
+ tftp[i][j].mask.dst.protonum = 0xFF;
+ tftp[i][j].mask.src.u.udp.port = htons(0xFFFF);
+ tftp[i][j].max_expected = 1;
+ tftp[i][j].timeout = 5 * 60; /* 5 minutes */
+ tftp[i][j].me = THIS_MODULE;
+ tftp[i][j].help = tftp_help;
+
+ tmpname = &tftp_names[i][j][0];
+ if (ports[i] == TFTP_PORT)
+ sprintf(tmpname, "tftp");
+ else
+ sprintf(tmpname, "tftp-%u", i);
+ tftp[i][j].name = tmpname;
+
+ ret = nf_conntrack_helper_register(&tftp[i][j]);
+ if (ret) {
+ printk("nf_ct_tftp: failed to register helper "
+ "for pf: %u port: %u\n",
+ tftp[i][j].tuple.src.l3num, ports[i]);
+ nf_conntrack_tftp_fini();
+ return ret;
+ }
+ }
+ }
+ return 0;
+}
+
+module_init(nf_conntrack_tftp_init);
+module_exit(nf_conntrack_tftp_fini);
