| /* Amanda extension for IP connection tracking, Version 0.2 |
| * (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca> |
| * based on HW's ip_conntrack_irc.c as well as other modules |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| * |
| * Module load syntax: |
| * insmod ip_conntrack_amanda.o [master_timeout=n] |
| * |
| * Where master_timeout is the timeout (in seconds) of the master |
| * connection (port 10080). This defaults to 5 minutes but if |
| * your clients take longer than 5 minutes to do their work |
| * before getting back to the Amanda server, you can increase |
| * this value. |
| * |
| */ |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/moduleparam.h> |
| #include <linux/textsearch.h> |
| #include <linux/skbuff.h> |
| #include <linux/in.h> |
| #include <linux/ip.h> |
| #include <linux/udp.h> |
| |
| #include <linux/netfilter.h> |
| #include <linux/netfilter_ipv4/ip_conntrack_helper.h> |
| #include <linux/netfilter_ipv4/ip_conntrack_amanda.h> |
| |
| static unsigned int master_timeout = 300; |
| static char *ts_algo = "kmp"; |
| |
| MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>"); |
| MODULE_DESCRIPTION("Amanda connection tracking module"); |
| MODULE_LICENSE("GPL"); |
| module_param(master_timeout, uint, 0600); |
| MODULE_PARM_DESC(master_timeout, "timeout for the master connection"); |
| module_param(ts_algo, charp, 0400); |
| MODULE_PARM_DESC(ts_algo, "textsearch algorithm to use (default kmp)"); |
| |
| unsigned int (*ip_nat_amanda_hook)(struct sk_buff **pskb, |
| enum ip_conntrack_info ctinfo, |
| unsigned int matchoff, |
| unsigned int matchlen, |
| struct ip_conntrack_expect *exp); |
| EXPORT_SYMBOL_GPL(ip_nat_amanda_hook); |
| |
| enum amanda_strings { |
| SEARCH_CONNECT, |
| SEARCH_NEWLINE, |
| SEARCH_DATA, |
| SEARCH_MESG, |
| SEARCH_INDEX, |
| }; |
| |
| static struct { |
| char *string; |
| size_t len; |
| struct ts_config *ts; |
| } search[] = { |
| [SEARCH_CONNECT] = { |
| .string = "CONNECT ", |
| .len = 8, |
| }, |
| [SEARCH_NEWLINE] = { |
| .string = "\n", |
| .len = 1, |
| }, |
| [SEARCH_DATA] = { |
| .string = "DATA ", |
| .len = 5, |
| }, |
| [SEARCH_MESG] = { |
| .string = "MESG ", |
| .len = 5, |
| }, |
| [SEARCH_INDEX] = { |
| .string = "INDEX ", |
| .len = 6, |
| }, |
| }; |
| |
| static int help(struct sk_buff **pskb, |
| struct ip_conntrack *ct, enum ip_conntrack_info ctinfo) |
| { |
| struct ts_state ts; |
| struct ip_conntrack_expect *exp; |
| unsigned int dataoff, start, stop, off, i; |
| char pbuf[sizeof("65535")], *tmp; |
| u_int16_t port, len; |
| int ret = NF_ACCEPT; |
| typeof(ip_nat_amanda_hook) ip_nat_amanda; |
| |
| /* Only look at packets from the Amanda server */ |
| if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) |
| return NF_ACCEPT; |
| |
| /* increase the UDP timeout of the master connection as replies from |
| * Amanda clients to the server can be quite delayed */ |
| ip_ct_refresh(ct, *pskb, master_timeout * HZ); |
| |
| /* No data? */ |
| dataoff = (*pskb)->nh.iph->ihl*4 + sizeof(struct udphdr); |
| if (dataoff >= (*pskb)->len) { |
| if (net_ratelimit()) |
| printk("amanda_help: skblen = %u\n", (*pskb)->len); |
| return NF_ACCEPT; |
| } |
| |
| memset(&ts, 0, sizeof(ts)); |
| start = skb_find_text(*pskb, dataoff, (*pskb)->len, |
| search[SEARCH_CONNECT].ts, &ts); |
| if (start == UINT_MAX) |
| goto out; |
| start += dataoff + search[SEARCH_CONNECT].len; |
| |
| memset(&ts, 0, sizeof(ts)); |
| stop = skb_find_text(*pskb, start, (*pskb)->len, |
| search[SEARCH_NEWLINE].ts, &ts); |
| if (stop == UINT_MAX) |
| goto out; |
| stop += start; |
| |
| for (i = SEARCH_DATA; i <= SEARCH_INDEX; i++) { |
| memset(&ts, 0, sizeof(ts)); |
| off = skb_find_text(*pskb, start, stop, search[i].ts, &ts); |
| if (off == UINT_MAX) |
| continue; |
| off += start + search[i].len; |
| |
| len = min_t(unsigned int, sizeof(pbuf) - 1, stop - off); |
| if (skb_copy_bits(*pskb, off, pbuf, len)) |
| break; |
| pbuf[len] = '\0'; |
| |
| port = simple_strtoul(pbuf, &tmp, 10); |
| len = tmp - pbuf; |
| if (port == 0 || len > 5) |
| break; |
| |
| exp = ip_conntrack_expect_alloc(ct); |
| if (exp == NULL) { |
| ret = NF_DROP; |
| goto out; |
| } |
| |
| exp->expectfn = NULL; |
| exp->flags = 0; |
| |
| exp->tuple.src.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip; |
| exp->tuple.src.u.tcp.port = 0; |
| exp->tuple.dst.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip; |
| exp->tuple.dst.protonum = IPPROTO_TCP; |
| exp->tuple.dst.u.tcp.port = htons(port); |
| |
| exp->mask.src.ip = htonl(0xFFFFFFFF); |
| exp->mask.src.u.tcp.port = 0; |
| exp->mask.dst.ip = htonl(0xFFFFFFFF); |
| exp->mask.dst.protonum = 0xFF; |
| exp->mask.dst.u.tcp.port = htons(0xFFFF); |
| |
| /* RCU read locked by nf_hook_slow */ |
| ip_nat_amanda = rcu_dereference(ip_nat_amanda_hook); |
| if (ip_nat_amanda) |
| ret = ip_nat_amanda(pskb, ctinfo, off - dataoff, |
| len, exp); |
| else if (ip_conntrack_expect_related(exp) != 0) |
| ret = NF_DROP; |
| ip_conntrack_expect_put(exp); |
| } |
| |
| out: |
| return ret; |
| } |
| |
| static struct ip_conntrack_helper amanda_helper = { |
| .max_expected = 3, |
| .timeout = 180, |
| .me = THIS_MODULE, |
| .help = help, |
| .name = "amanda", |
| |
| .tuple = { .src = { .u = { .udp = {.port = __constant_htons(10080) } } }, |
| .dst = { .protonum = IPPROTO_UDP }, |
| }, |
| .mask = { .src = { .u = { 0xFFFF } }, |
| .dst = { .protonum = 0xFF }, |
| }, |
| }; |
| |
| static void __exit ip_conntrack_amanda_fini(void) |
| { |
| int i; |
| |
| ip_conntrack_helper_unregister(&amanda_helper); |
| for (i = 0; i < ARRAY_SIZE(search); i++) |
| textsearch_destroy(search[i].ts); |
| } |
| |
| static int __init ip_conntrack_amanda_init(void) |
| { |
| int ret, i; |
| |
| ret = -ENOMEM; |
| for (i = 0; i < ARRAY_SIZE(search); i++) { |
| search[i].ts = textsearch_prepare(ts_algo, search[i].string, |
| search[i].len, |
| GFP_KERNEL, TS_AUTOLOAD); |
| if (search[i].ts == NULL) |
| goto err; |
| } |
| ret = ip_conntrack_helper_register(&amanda_helper); |
| if (ret < 0) |
| goto err; |
| return 0; |
| |
| err: |
| for (; i >= 0; i--) { |
| if (search[i].ts) |
| textsearch_destroy(search[i].ts); |
| } |
| return ret; |
| } |
| |
| module_init(ip_conntrack_amanda_init); |
| module_exit(ip_conntrack_amanda_fini); |