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- /* Amanda extension for IP connection tracking
- *
- * (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca>
- * based on HW's ip_conntrack_irc.c as well as other modules
- * (C) 2006 Patrick McHardy <kaber@trash.net>
- *
- * 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.
- */
- #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/udp.h>
- #include <linux/netfilter.h>
- #include <linux/gfp.h>
- #include <net/netfilter/nf_conntrack.h>
- #include <net/netfilter/nf_conntrack_expect.h>
- #include <net/netfilter/nf_conntrack_ecache.h>
- #include <net/netfilter/nf_conntrack_helper.h>
- #include <linux/netfilter/nf_conntrack_amanda.h>
- static unsigned int master_timeout __read_mostly = 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_ALIAS("ip_conntrack_amanda");
- MODULE_ALIAS_NFCT_HELPER("amanda");
- 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 (*nf_nat_amanda_hook)(struct sk_buff *skb,
- enum ip_conntrack_info ctinfo,
- unsigned int protoff,
- unsigned int matchoff,
- unsigned int matchlen,
- struct nf_conntrack_expect *exp)
- __read_mostly;
- EXPORT_SYMBOL_GPL(nf_nat_amanda_hook);
- enum amanda_strings {
- SEARCH_CONNECT,
- SEARCH_NEWLINE,
- SEARCH_DATA,
- SEARCH_MESG,
- SEARCH_INDEX,
- };
- static struct {
- const char *string;
- size_t len;
- struct ts_config *ts;
- } search[] __read_mostly = {
- [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 amanda_help(struct sk_buff *skb,
- unsigned int protoff,
- struct nf_conn *ct,
- enum ip_conntrack_info ctinfo)
- {
- struct nf_conntrack_expect *exp;
- struct nf_conntrack_tuple *tuple;
- unsigned int dataoff, start, stop, off, i;
- char pbuf[sizeof("65535")], *tmp;
- u_int16_t len;
- __be16 port;
- int ret = NF_ACCEPT;
- typeof(nf_nat_amanda_hook) nf_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 */
- nf_ct_refresh(ct, skb, master_timeout * HZ);
- /* No data? */
- dataoff = protoff + sizeof(struct udphdr);
- if (dataoff >= skb->len) {
- net_err_ratelimited("amanda_help: skblen = %u\n", skb->len);
- return NF_ACCEPT;
- }
- start = skb_find_text(skb, dataoff, skb->len,
- search[SEARCH_CONNECT].ts);
- if (start == UINT_MAX)
- goto out;
- start += dataoff + search[SEARCH_CONNECT].len;
- stop = skb_find_text(skb, start, skb->len,
- search[SEARCH_NEWLINE].ts);
- if (stop == UINT_MAX)
- goto out;
- stop += start;
- for (i = SEARCH_DATA; i <= SEARCH_INDEX; i++) {
- off = skb_find_text(skb, start, stop, search[i].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(skb, off, pbuf, len))
- break;
- pbuf[len] = '\0';
- port = htons(simple_strtoul(pbuf, &tmp, 10));
- len = tmp - pbuf;
- if (port == 0 || len > 5)
- break;
- exp = nf_ct_expect_alloc(ct);
- if (exp == NULL) {
- nf_ct_helper_log(skb, ct, "cannot alloc expectation");
- ret = NF_DROP;
- goto out;
- }
- tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
- nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT,
- nf_ct_l3num(ct),
- &tuple->src.u3, &tuple->dst.u3,
- IPPROTO_TCP, NULL, &port);
- nf_nat_amanda = rcu_dereference(nf_nat_amanda_hook);
- if (nf_nat_amanda && ct->status & IPS_NAT_MASK)
- ret = nf_nat_amanda(skb, ctinfo, protoff,
- off - dataoff, len, exp);
- else if (nf_ct_expect_related(exp) != 0) {
- nf_ct_helper_log(skb, ct, "cannot add expectation");
- ret = NF_DROP;
- }
- nf_ct_expect_put(exp);
- }
- out:
- return ret;
- }
- static const struct nf_conntrack_expect_policy amanda_exp_policy = {
- .max_expected = 3,
- .timeout = 180,
- };
- static struct nf_conntrack_helper amanda_helper[2] __read_mostly = {
- {
- .name = "amanda",
- .me = THIS_MODULE,
- .help = amanda_help,
- .tuple.src.l3num = AF_INET,
- .tuple.src.u.udp.port = cpu_to_be16(10080),
- .tuple.dst.protonum = IPPROTO_UDP,
- .expect_policy = &amanda_exp_policy,
- },
- {
- .name = "amanda",
- .me = THIS_MODULE,
- .help = amanda_help,
- .tuple.src.l3num = AF_INET6,
- .tuple.src.u.udp.port = cpu_to_be16(10080),
- .tuple.dst.protonum = IPPROTO_UDP,
- .expect_policy = &amanda_exp_policy,
- },
- };
- static void __exit nf_conntrack_amanda_fini(void)
- {
- int i;
- nf_conntrack_helper_unregister(&amanda_helper[0]);
- nf_conntrack_helper_unregister(&amanda_helper[1]);
- for (i = 0; i < ARRAY_SIZE(search); i++)
- textsearch_destroy(search[i].ts);
- }
- static int __init nf_conntrack_amanda_init(void)
- {
- int ret, i;
- 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 (IS_ERR(search[i].ts)) {
- ret = PTR_ERR(search[i].ts);
- goto err1;
- }
- }
- ret = nf_conntrack_helper_register(&amanda_helper[0]);
- if (ret < 0)
- goto err1;
- ret = nf_conntrack_helper_register(&amanda_helper[1]);
- if (ret < 0)
- goto err2;
- return 0;
- err2:
- nf_conntrack_helper_unregister(&amanda_helper[0]);
- err1:
- while (--i >= 0)
- textsearch_destroy(search[i].ts);
- return ret;
- }
- module_init(nf_conntrack_amanda_init);
- module_exit(nf_conntrack_amanda_fini);
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