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);