Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6] / net / netfilter / nf_conntrack_tftp.c
1 /* (C) 2001-2002 Magnus Boden <mb@ozaba.mine.nu>
2  *
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.
6  */
7
8 #include <linux/module.h>
9 #include <linux/moduleparam.h>
10 #include <linux/in.h>
11 #include <linux/udp.h>
12 #include <linux/netfilter.h>
13
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>
20
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");
25
26 #define MAX_PORTS 8
27 static unsigned short ports[MAX_PORTS];
28 static int ports_c;
29 module_param_array(ports, ushort, &ports_c, 0400);
30 MODULE_PARM_DESC(ports, "Port numbers of TFTP servers");
31
32 unsigned int (*nf_nat_tftp_hook)(struct sk_buff **pskb,
33                                  enum ip_conntrack_info ctinfo,
34                                  struct nf_conntrack_expect *exp) __read_mostly;
35 EXPORT_SYMBOL_GPL(nf_nat_tftp_hook);
36
37 static int tftp_help(struct sk_buff **pskb,
38                      unsigned int protoff,
39                      struct nf_conn *ct,
40                      enum ip_conntrack_info ctinfo)
41 {
42         struct tftphdr _tftph, *tfh;
43         struct nf_conntrack_expect *exp;
44         struct nf_conntrack_tuple *tuple;
45         unsigned int ret = NF_ACCEPT;
46         int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
47         typeof(nf_nat_tftp_hook) nf_nat_tftp;
48
49         tfh = skb_header_pointer(*pskb, protoff + sizeof(struct udphdr),
50                                  sizeof(_tftph), &_tftph);
51         if (tfh == NULL)
52                 return NF_ACCEPT;
53
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);
60
61                 exp = nf_ct_expect_alloc(ct);
62                 if (exp == NULL)
63                         return NF_DROP;
64                 tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
65                 nf_ct_expect_init(exp, family, &tuple->src.u3, &tuple->dst.u3,
66                                   IPPROTO_UDP, NULL, &tuple->dst.u.udp.port);
67
68                 pr_debug("expect: ");
69                 NF_CT_DUMP_TUPLE(&exp->tuple);
70
71                 nf_nat_tftp = rcu_dereference(nf_nat_tftp_hook);
72                 if (nf_nat_tftp && ct->status & IPS_NAT_MASK)
73                         ret = nf_nat_tftp(pskb, ctinfo, exp);
74                 else if (nf_ct_expect_related(exp) != 0)
75                         ret = NF_DROP;
76                 nf_ct_expect_put(exp);
77                 break;
78         case TFTP_OPCODE_DATA:
79         case TFTP_OPCODE_ACK:
80                 pr_debug("Data/ACK opcode\n");
81                 break;
82         case TFTP_OPCODE_ERROR:
83                 pr_debug("Error opcode\n");
84                 break;
85         default:
86                 pr_debug("Unknown opcode\n");
87         }
88         return ret;
89 }
90
91 static struct nf_conntrack_helper tftp[MAX_PORTS][2] __read_mostly;
92 static char tftp_names[MAX_PORTS][2][sizeof("tftp-65535")] __read_mostly;
93
94 static void nf_conntrack_tftp_fini(void)
95 {
96         int i, j;
97
98         for (i = 0; i < ports_c; i++) {
99                 for (j = 0; j < 2; j++)
100                         nf_conntrack_helper_unregister(&tftp[i][j]);
101         }
102 }
103
104 static int __init nf_conntrack_tftp_init(void)
105 {
106         int i, j, ret;
107         char *tmpname;
108
109         if (ports_c == 0)
110                 ports[ports_c++] = TFTP_PORT;
111
112         for (i = 0; i < ports_c; i++) {
113                 memset(&tftp[i], 0, sizeof(tftp[i]));
114
115                 tftp[i][0].tuple.src.l3num = AF_INET;
116                 tftp[i][1].tuple.src.l3num = AF_INET6;
117                 for (j = 0; j < 2; j++) {
118                         tftp[i][j].tuple.dst.protonum = IPPROTO_UDP;
119                         tftp[i][j].tuple.src.u.udp.port = htons(ports[i]);
120                         tftp[i][j].max_expected = 1;
121                         tftp[i][j].timeout = 5 * 60; /* 5 minutes */
122                         tftp[i][j].me = THIS_MODULE;
123                         tftp[i][j].help = tftp_help;
124
125                         tmpname = &tftp_names[i][j][0];
126                         if (ports[i] == TFTP_PORT)
127                                 sprintf(tmpname, "tftp");
128                         else
129                                 sprintf(tmpname, "tftp-%u", i);
130                         tftp[i][j].name = tmpname;
131
132                         ret = nf_conntrack_helper_register(&tftp[i][j]);
133                         if (ret) {
134                                 printk("nf_ct_tftp: failed to register helper "
135                                        "for pf: %u port: %u\n",
136                                         tftp[i][j].tuple.src.l3num, ports[i]);
137                                 nf_conntrack_tftp_fini();
138                                 return ret;
139                         }
140                 }
141         }
142         return 0;
143 }
144
145 module_init(nf_conntrack_tftp_init);
146 module_exit(nf_conntrack_tftp_fini);