1 /* (C) 2001-2002 Magnus Boden <mb@ozaba.mine.nu>
3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License version 2 as
5 * published by the Free Software Foundation.
8 #include <linux/module.h>
9 #include <linux/moduleparam.h>
11 #include <linux/udp.h>
12 #include <linux/netfilter.h>
14 #include <net/netfilter/nf_conntrack.h>
15 #include <net/netfilter/nf_conntrack_tuple.h>
16 #include <net/netfilter/nf_conntrack_expect.h>
17 #include <net/netfilter/nf_conntrack_ecache.h>
18 #include <net/netfilter/nf_conntrack_helper.h>
19 #include <linux/netfilter/nf_conntrack_tftp.h>
21 MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>");
22 MODULE_DESCRIPTION("TFTP connection tracking helper");
23 MODULE_LICENSE("GPL");
24 MODULE_ALIAS("ip_conntrack_tftp");
27 static unsigned short ports
[MAX_PORTS
];
28 static unsigned int ports_c
;
29 module_param_array(ports
, ushort
, &ports_c
, 0400);
30 MODULE_PARM_DESC(ports
, "Port numbers of TFTP servers");
32 unsigned int (*nf_nat_tftp_hook
)(struct sk_buff
*skb
,
33 enum ip_conntrack_info ctinfo
,
34 struct nf_conntrack_expect
*exp
) __read_mostly
;
35 EXPORT_SYMBOL_GPL(nf_nat_tftp_hook
);
37 static int tftp_help(struct sk_buff
*skb
,
40 enum ip_conntrack_info ctinfo
)
42 const struct tftphdr
*tfh
;
43 struct tftphdr _tftph
;
44 struct nf_conntrack_expect
*exp
;
45 struct nf_conntrack_tuple
*tuple
;
46 unsigned int ret
= NF_ACCEPT
;
47 typeof(nf_nat_tftp_hook
) nf_nat_tftp
;
49 tfh
= skb_header_pointer(skb
, protoff
+ sizeof(struct udphdr
),
50 sizeof(_tftph
), &_tftph
);
54 switch (ntohs(tfh
->opcode
)) {
55 case TFTP_OPCODE_READ
:
56 case TFTP_OPCODE_WRITE
:
57 /* RRQ and WRQ works the same way */
58 nf_ct_dump_tuple(&ct
->tuplehash
[IP_CT_DIR_ORIGINAL
].tuple
);
59 nf_ct_dump_tuple(&ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
);
61 exp
= nf_ct_expect_alloc(ct
);
64 tuple
= &ct
->tuplehash
[IP_CT_DIR_REPLY
].tuple
;
65 nf_ct_expect_init(exp
, NF_CT_EXPECT_CLASS_DEFAULT
,
67 &tuple
->src
.u3
, &tuple
->dst
.u3
,
68 IPPROTO_UDP
, NULL
, &tuple
->dst
.u
.udp
.port
);
71 nf_ct_dump_tuple(&exp
->tuple
);
73 nf_nat_tftp
= rcu_dereference(nf_nat_tftp_hook
);
74 if (nf_nat_tftp
&& ct
->status
& IPS_NAT_MASK
)
75 ret
= nf_nat_tftp(skb
, ctinfo
, exp
);
76 else if (nf_ct_expect_related(exp
) != 0)
78 nf_ct_expect_put(exp
);
80 case TFTP_OPCODE_DATA
:
82 pr_debug("Data/ACK opcode\n");
84 case TFTP_OPCODE_ERROR
:
85 pr_debug("Error opcode\n");
88 pr_debug("Unknown opcode\n");
93 static struct nf_conntrack_helper tftp
[MAX_PORTS
][2] __read_mostly
;
94 static char tftp_names
[MAX_PORTS
][2][sizeof("tftp-65535")] __read_mostly
;
96 static const struct nf_conntrack_expect_policy tftp_exp_policy
= {
101 static void nf_conntrack_tftp_fini(void)
105 for (i
= 0; i
< ports_c
; i
++) {
106 for (j
= 0; j
< 2; j
++)
107 nf_conntrack_helper_unregister(&tftp
[i
][j
]);
111 static int __init
nf_conntrack_tftp_init(void)
117 ports
[ports_c
++] = TFTP_PORT
;
119 for (i
= 0; i
< ports_c
; i
++) {
120 memset(&tftp
[i
], 0, sizeof(tftp
[i
]));
122 tftp
[i
][0].tuple
.src
.l3num
= AF_INET
;
123 tftp
[i
][1].tuple
.src
.l3num
= AF_INET6
;
124 for (j
= 0; j
< 2; j
++) {
125 tftp
[i
][j
].tuple
.dst
.protonum
= IPPROTO_UDP
;
126 tftp
[i
][j
].tuple
.src
.u
.udp
.port
= htons(ports
[i
]);
127 tftp
[i
][j
].expect_policy
= &tftp_exp_policy
;
128 tftp
[i
][j
].me
= THIS_MODULE
;
129 tftp
[i
][j
].help
= tftp_help
;
131 tmpname
= &tftp_names
[i
][j
][0];
132 if (ports
[i
] == TFTP_PORT
)
133 sprintf(tmpname
, "tftp");
135 sprintf(tmpname
, "tftp-%u", i
);
136 tftp
[i
][j
].name
= tmpname
;
138 ret
= nf_conntrack_helper_register(&tftp
[i
][j
]);
140 printk("nf_ct_tftp: failed to register helper "
141 "for pf: %u port: %u\n",
142 tftp
[i
][j
].tuple
.src
.l3num
, ports
[i
]);
143 nf_conntrack_tftp_fini();
151 module_init(nf_conntrack_tftp_init
);
152 module_exit(nf_conntrack_tftp_fini
);