Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
230 lines
5.8 KiB
C
230 lines
5.8 KiB
C
/* Amanda extension for IP connection tracking, Version 0.2
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* (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca>
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* based on HW's ip_conntrack_irc.c as well as other modules
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Module load syntax:
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* insmod ip_conntrack_amanda.o [master_timeout=n]
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*
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* Where master_timeout is the timeout (in seconds) of the master
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* connection (port 10080). This defaults to 5 minutes but if
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* your clients take longer than 5 minutes to do their work
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* before getting back to the Amanda server, you can increase
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* this value.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/textsearch.h>
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#include <linux/skbuff.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <linux/udp.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
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#include <linux/netfilter_ipv4/ip_conntrack_amanda.h>
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static unsigned int master_timeout = 300;
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static char *ts_algo = "kmp";
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MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>");
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MODULE_DESCRIPTION("Amanda connection tracking module");
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MODULE_LICENSE("GPL");
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module_param(master_timeout, uint, 0600);
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MODULE_PARM_DESC(master_timeout, "timeout for the master connection");
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module_param(ts_algo, charp, 0400);
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MODULE_PARM_DESC(ts_algo, "textsearch algorithm to use (default kmp)");
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unsigned int (*ip_nat_amanda_hook)(struct sk_buff **pskb,
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enum ip_conntrack_info ctinfo,
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unsigned int matchoff,
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unsigned int matchlen,
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struct ip_conntrack_expect *exp);
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EXPORT_SYMBOL_GPL(ip_nat_amanda_hook);
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enum amanda_strings {
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SEARCH_CONNECT,
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SEARCH_NEWLINE,
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SEARCH_DATA,
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SEARCH_MESG,
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SEARCH_INDEX,
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};
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static struct {
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char *string;
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size_t len;
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struct ts_config *ts;
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} search[] = {
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[SEARCH_CONNECT] = {
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.string = "CONNECT ",
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.len = 8,
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},
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[SEARCH_NEWLINE] = {
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.string = "\n",
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.len = 1,
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},
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[SEARCH_DATA] = {
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.string = "DATA ",
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.len = 5,
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},
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[SEARCH_MESG] = {
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.string = "MESG ",
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.len = 5,
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},
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[SEARCH_INDEX] = {
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.string = "INDEX ",
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.len = 6,
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},
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};
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static int help(struct sk_buff **pskb,
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struct ip_conntrack *ct, enum ip_conntrack_info ctinfo)
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{
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struct ts_state ts;
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struct ip_conntrack_expect *exp;
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unsigned int dataoff, start, stop, off, i;
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char pbuf[sizeof("65535")], *tmp;
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u_int16_t port, len;
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int ret = NF_ACCEPT;
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typeof(ip_nat_amanda_hook) ip_nat_amanda;
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/* Only look at packets from the Amanda server */
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if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
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return NF_ACCEPT;
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/* increase the UDP timeout of the master connection as replies from
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* Amanda clients to the server can be quite delayed */
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ip_ct_refresh(ct, *pskb, master_timeout * HZ);
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/* No data? */
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dataoff = (*pskb)->nh.iph->ihl*4 + sizeof(struct udphdr);
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if (dataoff >= (*pskb)->len) {
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if (net_ratelimit())
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printk("amanda_help: skblen = %u\n", (*pskb)->len);
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return NF_ACCEPT;
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}
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memset(&ts, 0, sizeof(ts));
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start = skb_find_text(*pskb, dataoff, (*pskb)->len,
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search[SEARCH_CONNECT].ts, &ts);
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if (start == UINT_MAX)
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goto out;
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start += dataoff + search[SEARCH_CONNECT].len;
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memset(&ts, 0, sizeof(ts));
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stop = skb_find_text(*pskb, start, (*pskb)->len,
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search[SEARCH_NEWLINE].ts, &ts);
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if (stop == UINT_MAX)
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goto out;
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stop += start;
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for (i = SEARCH_DATA; i <= SEARCH_INDEX; i++) {
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memset(&ts, 0, sizeof(ts));
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off = skb_find_text(*pskb, start, stop, search[i].ts, &ts);
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if (off == UINT_MAX)
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continue;
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off += start + search[i].len;
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len = min_t(unsigned int, sizeof(pbuf) - 1, stop - off);
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if (skb_copy_bits(*pskb, off, pbuf, len))
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break;
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pbuf[len] = '\0';
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port = simple_strtoul(pbuf, &tmp, 10);
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len = tmp - pbuf;
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if (port == 0 || len > 5)
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break;
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exp = ip_conntrack_expect_alloc(ct);
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if (exp == NULL) {
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ret = NF_DROP;
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goto out;
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}
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exp->expectfn = NULL;
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exp->flags = 0;
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exp->tuple.src.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
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exp->tuple.src.u.tcp.port = 0;
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exp->tuple.dst.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip;
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exp->tuple.dst.protonum = IPPROTO_TCP;
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exp->tuple.dst.u.tcp.port = htons(port);
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exp->mask.src.ip = htonl(0xFFFFFFFF);
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exp->mask.src.u.tcp.port = 0;
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exp->mask.dst.ip = htonl(0xFFFFFFFF);
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exp->mask.dst.protonum = 0xFF;
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exp->mask.dst.u.tcp.port = htons(0xFFFF);
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/* RCU read locked by nf_hook_slow */
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ip_nat_amanda = rcu_dereference(ip_nat_amanda_hook);
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if (ip_nat_amanda)
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ret = ip_nat_amanda(pskb, ctinfo, off - dataoff,
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len, exp);
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else if (ip_conntrack_expect_related(exp) != 0)
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ret = NF_DROP;
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ip_conntrack_expect_put(exp);
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}
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out:
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return ret;
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}
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static struct ip_conntrack_helper amanda_helper = {
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.max_expected = 3,
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.timeout = 180,
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.me = THIS_MODULE,
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.help = help,
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.name = "amanda",
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.tuple = { .src = { .u = { .udp = {.port = __constant_htons(10080) } } },
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.dst = { .protonum = IPPROTO_UDP },
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},
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.mask = { .src = { .u = { 0xFFFF } },
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.dst = { .protonum = 0xFF },
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},
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};
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static void __exit ip_conntrack_amanda_fini(void)
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{
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int i;
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ip_conntrack_helper_unregister(&amanda_helper);
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for (i = 0; i < ARRAY_SIZE(search); i++)
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textsearch_destroy(search[i].ts);
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}
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static int __init ip_conntrack_amanda_init(void)
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{
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int ret, i;
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ret = -ENOMEM;
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for (i = 0; i < ARRAY_SIZE(search); i++) {
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search[i].ts = textsearch_prepare(ts_algo, search[i].string,
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search[i].len,
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GFP_KERNEL, TS_AUTOLOAD);
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if (search[i].ts == NULL)
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goto err;
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}
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ret = ip_conntrack_helper_register(&amanda_helper);
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if (ret < 0)
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goto err;
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return 0;
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err:
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for (; i >= 0; i--) {
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if (search[i].ts)
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textsearch_destroy(search[i].ts);
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}
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return ret;
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}
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module_init(ip_conntrack_amanda_init);
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module_exit(ip_conntrack_amanda_fini);
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