Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* Amanda extension for IP connection tracking, Version 0.2 |
| 2 | * (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca> |
| 3 | * based on HW's ip_conntrack_irc.c as well as other modules |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU General Public License |
| 7 | * as published by the Free Software Foundation; either version |
| 8 | * 2 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * Module load syntax: |
| 11 | * insmod ip_conntrack_amanda.o [master_timeout=n] |
| 12 | * |
| 13 | * Where master_timeout is the timeout (in seconds) of the master |
| 14 | * connection (port 10080). This defaults to 5 minutes but if |
| 15 | * your clients take longer than 5 minutes to do their work |
| 16 | * before getting back to the Amanda server, you can increase |
| 17 | * this value. |
| 18 | * |
| 19 | */ |
| 20 | |
| 21 | #include <linux/kernel.h> |
| 22 | #include <linux/module.h> |
| 23 | #include <linux/netfilter.h> |
| 24 | #include <linux/ip.h> |
| 25 | #include <linux/moduleparam.h> |
| 26 | #include <net/checksum.h> |
| 27 | #include <net/udp.h> |
| 28 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <linux/netfilter_ipv4/ip_conntrack_helper.h> |
| 30 | #include <linux/netfilter_ipv4/ip_conntrack_amanda.h> |
| 31 | |
| 32 | static unsigned int master_timeout = 300; |
| 33 | |
| 34 | MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>"); |
| 35 | MODULE_DESCRIPTION("Amanda connection tracking module"); |
| 36 | MODULE_LICENSE("GPL"); |
| 37 | module_param(master_timeout, int, 0600); |
| 38 | MODULE_PARM_DESC(master_timeout, "timeout for the master connection"); |
| 39 | |
| 40 | static char *conns[] = { "DATA ", "MESG ", "INDEX " }; |
| 41 | |
| 42 | /* This is slow, but it's simple. --RR */ |
| 43 | static char amanda_buffer[65536]; |
Patrick McHardy | e45b1be | 2005-06-21 14:01:30 -0700 | [diff] [blame] | 44 | static DEFINE_SPINLOCK(amanda_buffer_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | |
| 46 | unsigned int (*ip_nat_amanda_hook)(struct sk_buff **pskb, |
| 47 | enum ip_conntrack_info ctinfo, |
| 48 | unsigned int matchoff, |
| 49 | unsigned int matchlen, |
| 50 | struct ip_conntrack_expect *exp); |
| 51 | EXPORT_SYMBOL_GPL(ip_nat_amanda_hook); |
| 52 | |
| 53 | static int help(struct sk_buff **pskb, |
| 54 | struct ip_conntrack *ct, enum ip_conntrack_info ctinfo) |
| 55 | { |
| 56 | struct ip_conntrack_expect *exp; |
| 57 | char *data, *data_limit, *tmp; |
| 58 | unsigned int dataoff, i; |
| 59 | u_int16_t port, len; |
| 60 | int ret = NF_ACCEPT; |
| 61 | |
| 62 | /* Only look at packets from the Amanda server */ |
| 63 | if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) |
| 64 | return NF_ACCEPT; |
| 65 | |
| 66 | /* increase the UDP timeout of the master connection as replies from |
| 67 | * Amanda clients to the server can be quite delayed */ |
| 68 | ip_ct_refresh_acct(ct, ctinfo, NULL, master_timeout * HZ); |
| 69 | |
| 70 | /* No data? */ |
| 71 | dataoff = (*pskb)->nh.iph->ihl*4 + sizeof(struct udphdr); |
| 72 | if (dataoff >= (*pskb)->len) { |
| 73 | if (net_ratelimit()) |
| 74 | printk("amanda_help: skblen = %u\n", (*pskb)->len); |
| 75 | return NF_ACCEPT; |
| 76 | } |
| 77 | |
Patrick McHardy | e45b1be | 2005-06-21 14:01:30 -0700 | [diff] [blame] | 78 | spin_lock_bh(&amanda_buffer_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | skb_copy_bits(*pskb, dataoff, amanda_buffer, (*pskb)->len - dataoff); |
| 80 | data = amanda_buffer; |
| 81 | data_limit = amanda_buffer + (*pskb)->len - dataoff; |
| 82 | *data_limit = '\0'; |
| 83 | |
| 84 | /* Search for the CONNECT string */ |
| 85 | data = strstr(data, "CONNECT "); |
| 86 | if (!data) |
| 87 | goto out; |
| 88 | data += strlen("CONNECT "); |
| 89 | |
| 90 | /* Only search first line. */ |
| 91 | if ((tmp = strchr(data, '\n'))) |
| 92 | *tmp = '\0'; |
| 93 | |
| 94 | for (i = 0; i < ARRAY_SIZE(conns); i++) { |
| 95 | char *match = strstr(data, conns[i]); |
| 96 | if (!match) |
| 97 | continue; |
| 98 | tmp = data = match + strlen(conns[i]); |
| 99 | port = simple_strtoul(data, &data, 10); |
| 100 | len = data - tmp; |
| 101 | if (port == 0 || len > 5) |
| 102 | break; |
| 103 | |
| 104 | exp = ip_conntrack_expect_alloc(); |
| 105 | if (exp == NULL) { |
| 106 | ret = NF_DROP; |
| 107 | goto out; |
| 108 | } |
| 109 | |
| 110 | exp->expectfn = NULL; |
| 111 | exp->master = ct; |
| 112 | |
| 113 | exp->tuple.src.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip; |
| 114 | exp->tuple.src.u.tcp.port = 0; |
| 115 | exp->tuple.dst.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip; |
| 116 | exp->tuple.dst.protonum = IPPROTO_TCP; |
| 117 | exp->tuple.dst.u.tcp.port = htons(port); |
| 118 | |
| 119 | exp->mask.src.ip = 0xFFFFFFFF; |
| 120 | exp->mask.src.u.tcp.port = 0; |
| 121 | exp->mask.dst.ip = 0xFFFFFFFF; |
| 122 | exp->mask.dst.protonum = 0xFF; |
| 123 | exp->mask.dst.u.tcp.port = 0xFFFF; |
| 124 | |
| 125 | if (ip_nat_amanda_hook) |
| 126 | ret = ip_nat_amanda_hook(pskb, ctinfo, |
| 127 | tmp - amanda_buffer, |
| 128 | len, exp); |
| 129 | else if (ip_conntrack_expect_related(exp) != 0) { |
| 130 | ip_conntrack_expect_free(exp); |
| 131 | ret = NF_DROP; |
| 132 | } |
| 133 | } |
| 134 | |
| 135 | out: |
Patrick McHardy | e45b1be | 2005-06-21 14:01:30 -0700 | [diff] [blame] | 136 | spin_unlock_bh(&amanda_buffer_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | return ret; |
| 138 | } |
| 139 | |
| 140 | static struct ip_conntrack_helper amanda_helper = { |
| 141 | .max_expected = ARRAY_SIZE(conns), |
| 142 | .timeout = 180, |
| 143 | .me = THIS_MODULE, |
| 144 | .help = help, |
| 145 | .name = "amanda", |
| 146 | |
| 147 | .tuple = { .src = { .u = { __constant_htons(10080) } }, |
| 148 | .dst = { .protonum = IPPROTO_UDP }, |
| 149 | }, |
| 150 | .mask = { .src = { .u = { 0xFFFF } }, |
| 151 | .dst = { .protonum = 0xFF }, |
| 152 | }, |
| 153 | }; |
| 154 | |
| 155 | static void __exit fini(void) |
| 156 | { |
| 157 | ip_conntrack_helper_unregister(&amanda_helper); |
| 158 | } |
| 159 | |
| 160 | static int __init init(void) |
| 161 | { |
| 162 | return ip_conntrack_helper_register(&amanda_helper); |
| 163 | } |
| 164 | |
| 165 | module_init(init); |
| 166 | module_exit(fini); |