d4156e8cd9
Since conntrack currently allows to use masks for every bit of both helper and expectation tuples, we can't hash them and have to keep them on two global lists that are searched for every new connection. This patch removes the never used ability to use masks for the destination part of the expectation tuple and completely removes masks from helpers since the only reasonable choice is a full match on l3num, protonum and src.u.all. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
122 lines
3.3 KiB
C
122 lines
3.3 KiB
C
/*
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* NetBIOS name service broadcast connection tracking helper
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*
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* (c) 2005 Patrick McHardy <kaber@trash.net>
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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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/*
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* This helper tracks locally originating NetBIOS name service
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* requests by issuing permanent expectations (valid until
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* timing out) matching all reply connections from the
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* destination network. The only NetBIOS specific thing is
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* actually the port number.
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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/init.h>
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#include <linux/skbuff.h>
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#include <linux/netdevice.h>
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#include <linux/inetdevice.h>
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#include <linux/if_addr.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <linux/netfilter.h>
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#include <net/route.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_helper.h>
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#include <net/netfilter/nf_conntrack_expect.h>
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#define NMBD_PORT 137
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_DESCRIPTION("NetBIOS name service broadcast connection tracking helper");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("ip_conntrack_netbios_ns");
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static unsigned int timeout __read_mostly = 3;
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module_param(timeout, uint, 0400);
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MODULE_PARM_DESC(timeout, "timeout for master connection/replies in seconds");
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static int help(struct sk_buff **pskb, unsigned int protoff,
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struct nf_conn *ct, enum ip_conntrack_info ctinfo)
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{
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struct nf_conntrack_expect *exp;
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struct iphdr *iph = ip_hdr(*pskb);
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struct rtable *rt = (struct rtable *)(*pskb)->dst;
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struct in_device *in_dev;
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__be32 mask = 0;
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/* we're only interested in locally generated packets */
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if ((*pskb)->sk == NULL)
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goto out;
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if (rt == NULL || !(rt->rt_flags & RTCF_BROADCAST))
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goto out;
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if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
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goto out;
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rcu_read_lock();
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in_dev = __in_dev_get_rcu(rt->u.dst.dev);
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if (in_dev != NULL) {
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for_primary_ifa(in_dev) {
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if (ifa->ifa_broadcast == iph->daddr) {
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mask = ifa->ifa_mask;
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break;
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}
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} endfor_ifa(in_dev);
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}
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rcu_read_unlock();
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if (mask == 0)
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goto out;
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exp = nf_ct_expect_alloc(ct);
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if (exp == NULL)
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goto out;
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exp->tuple = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
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exp->tuple.src.u.udp.port = htons(NMBD_PORT);
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exp->mask.src.u3.ip = mask;
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exp->mask.src.u.udp.port = htons(0xFFFF);
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exp->expectfn = NULL;
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exp->flags = NF_CT_EXPECT_PERMANENT;
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exp->helper = NULL;
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nf_ct_expect_related(exp);
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nf_ct_expect_put(exp);
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nf_ct_refresh(ct, *pskb, timeout * HZ);
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out:
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return NF_ACCEPT;
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}
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static struct nf_conntrack_helper helper __read_mostly = {
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.name = "netbios-ns",
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.tuple.src.l3num = AF_INET,
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.tuple.src.u.udp.port = __constant_htons(NMBD_PORT),
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.tuple.dst.protonum = IPPROTO_UDP,
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.max_expected = 1,
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.me = THIS_MODULE,
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.help = help,
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};
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static int __init nf_conntrack_netbios_ns_init(void)
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{
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helper.timeout = timeout;
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return nf_conntrack_helper_register(&helper);
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}
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static void __exit nf_conntrack_netbios_ns_fini(void)
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{
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nf_conntrack_helper_unregister(&helper);
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}
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module_init(nf_conntrack_netbios_ns_init);
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module_exit(nf_conntrack_netbios_ns_fini);
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