Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | * Version: 0.0.7 |
| 8 | * |
| 9 | * Thu 21 Mar 2002 Harald Welte <laforge@gnumonks.org> |
| 10 | * - port to newnat API |
| 11 | * |
| 12 | */ |
| 13 | |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/ip.h> |
| 16 | #include <linux/udp.h> |
| 17 | |
| 18 | #include <linux/netfilter.h> |
| 19 | #include <linux/netfilter_ipv4/ip_tables.h> |
| 20 | #include <linux/netfilter_ipv4/ip_conntrack_helper.h> |
| 21 | #include <linux/netfilter_ipv4/ip_conntrack_tftp.h> |
| 22 | #include <linux/moduleparam.h> |
| 23 | |
| 24 | MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>"); |
| 25 | MODULE_DESCRIPTION("tftp connection tracking helper"); |
| 26 | MODULE_LICENSE("GPL"); |
| 27 | |
| 28 | #define MAX_PORTS 8 |
| 29 | static int ports[MAX_PORTS]; |
| 30 | static int ports_c; |
| 31 | module_param_array(ports, int, &ports_c, 0400); |
| 32 | MODULE_PARM_DESC(ports, "port numbers of tftp servers"); |
| 33 | |
| 34 | #if 0 |
| 35 | #define DEBUGP(format, args...) printk("%s:%s:" format, \ |
| 36 | __FILE__, __FUNCTION__ , ## args) |
| 37 | #else |
| 38 | #define DEBUGP(format, args...) |
| 39 | #endif |
| 40 | |
| 41 | unsigned int (*ip_nat_tftp_hook)(struct sk_buff **pskb, |
| 42 | enum ip_conntrack_info ctinfo, |
| 43 | struct ip_conntrack_expect *exp); |
| 44 | EXPORT_SYMBOL_GPL(ip_nat_tftp_hook); |
| 45 | |
| 46 | static int tftp_help(struct sk_buff **pskb, |
| 47 | struct ip_conntrack *ct, |
| 48 | enum ip_conntrack_info ctinfo) |
| 49 | { |
| 50 | struct tftphdr _tftph, *tfh; |
| 51 | struct ip_conntrack_expect *exp; |
| 52 | unsigned int ret = NF_ACCEPT; |
| 53 | |
| 54 | tfh = skb_header_pointer(*pskb, |
| 55 | (*pskb)->nh.iph->ihl*4+sizeof(struct udphdr), |
| 56 | sizeof(_tftph), &_tftph); |
| 57 | if (tfh == NULL) |
| 58 | return NF_ACCEPT; |
| 59 | |
| 60 | switch (ntohs(tfh->opcode)) { |
| 61 | /* RRQ and WRQ works the same way */ |
| 62 | case TFTP_OPCODE_READ: |
| 63 | case TFTP_OPCODE_WRITE: |
| 64 | DEBUGP(""); |
| 65 | DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); |
| 66 | DUMP_TUPLE(&ct->tuplehash[IP_CT_DIR_REPLY].tuple); |
| 67 | |
| 68 | exp = ip_conntrack_expect_alloc(); |
| 69 | if (exp == NULL) |
| 70 | return NF_DROP; |
| 71 | |
| 72 | exp->tuple = ct->tuplehash[IP_CT_DIR_REPLY].tuple; |
| 73 | exp->mask.src.ip = 0xffffffff; |
| 74 | exp->mask.dst.ip = 0xffffffff; |
| 75 | exp->mask.dst.u.udp.port = 0xffff; |
| 76 | exp->mask.dst.protonum = 0xff; |
| 77 | exp->expectfn = NULL; |
| 78 | exp->master = ct; |
| 79 | |
| 80 | DEBUGP("expect: "); |
| 81 | DUMP_TUPLE(&exp->tuple); |
| 82 | DUMP_TUPLE(&exp->mask); |
| 83 | if (ip_nat_tftp_hook) |
| 84 | ret = ip_nat_tftp_hook(pskb, ctinfo, exp); |
| 85 | else if (ip_conntrack_expect_related(exp) != 0) { |
| 86 | ip_conntrack_expect_free(exp); |
| 87 | ret = NF_DROP; |
| 88 | } |
| 89 | break; |
| 90 | case TFTP_OPCODE_DATA: |
| 91 | case TFTP_OPCODE_ACK: |
| 92 | DEBUGP("Data/ACK opcode\n"); |
| 93 | break; |
| 94 | case TFTP_OPCODE_ERROR: |
| 95 | DEBUGP("Error opcode\n"); |
| 96 | break; |
| 97 | default: |
| 98 | DEBUGP("Unknown opcode\n"); |
| 99 | } |
| 100 | return NF_ACCEPT; |
| 101 | } |
| 102 | |
| 103 | static struct ip_conntrack_helper tftp[MAX_PORTS]; |
| 104 | static char tftp_names[MAX_PORTS][10]; |
| 105 | |
| 106 | static void fini(void) |
| 107 | { |
| 108 | int i; |
| 109 | |
| 110 | for (i = 0 ; i < ports_c; i++) { |
| 111 | DEBUGP("unregistering helper for port %d\n", |
| 112 | ports[i]); |
| 113 | ip_conntrack_helper_unregister(&tftp[i]); |
| 114 | } |
| 115 | } |
| 116 | |
| 117 | static int __init init(void) |
| 118 | { |
| 119 | int i, ret; |
| 120 | char *tmpname; |
| 121 | |
| 122 | if (ports_c == 0) |
| 123 | ports[ports_c++] = TFTP_PORT; |
| 124 | |
| 125 | for (i = 0; i < ports_c; i++) { |
| 126 | /* Create helper structure */ |
| 127 | memset(&tftp[i], 0, sizeof(struct ip_conntrack_helper)); |
| 128 | |
| 129 | tftp[i].tuple.dst.protonum = IPPROTO_UDP; |
| 130 | tftp[i].tuple.src.u.udp.port = htons(ports[i]); |
| 131 | tftp[i].mask.dst.protonum = 0xFF; |
| 132 | tftp[i].mask.src.u.udp.port = 0xFFFF; |
| 133 | tftp[i].max_expected = 1; |
| 134 | tftp[i].timeout = 5 * 60; /* 5 minutes */ |
| 135 | tftp[i].me = THIS_MODULE; |
| 136 | tftp[i].help = tftp_help; |
| 137 | |
| 138 | tmpname = &tftp_names[i][0]; |
| 139 | if (ports[i] == TFTP_PORT) |
| 140 | sprintf(tmpname, "tftp"); |
| 141 | else |
| 142 | sprintf(tmpname, "tftp-%d", i); |
| 143 | tftp[i].name = tmpname; |
| 144 | |
| 145 | DEBUGP("port #%d: %d\n", i, ports[i]); |
| 146 | |
| 147 | ret=ip_conntrack_helper_register(&tftp[i]); |
| 148 | if (ret) { |
| 149 | printk("ERROR registering helper for port %d\n", |
| 150 | ports[i]); |
| 151 | fini(); |
| 152 | return(ret); |
| 153 | } |
| 154 | } |
| 155 | return(0); |
| 156 | } |
| 157 | |
| 158 | module_init(init); |
| 159 | module_exit(fini); |