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- /*
- * broadcast connection tracking helper
- *
- * (c) 2005 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/module.h>
- #include <linux/ip.h>
- #include <net/route.h>
- #include <linux/inetdevice.h>
- #include <linux/skbuff.h>
- #include <net/netfilter/nf_conntrack.h>
- #include <net/netfilter/nf_conntrack_helper.h>
- #include <net/netfilter/nf_conntrack_expect.h>
- int nf_conntrack_broadcast_help(struct sk_buff *skb,
- unsigned int protoff,
- struct nf_conn *ct,
- enum ip_conntrack_info ctinfo,
- unsigned int timeout)
- {
- struct nf_conntrack_expect *exp;
- struct iphdr *iph = ip_hdr(skb);
- struct rtable *rt = skb_rtable(skb);
- struct in_device *in_dev;
- struct nf_conn_help *help = nfct_help(ct);
- __be32 mask = 0;
- /* we're only interested in locally generated packets */
- if (skb->sk == NULL)
- goto out;
- if (rt == NULL || !(rt->rt_flags & RTCF_BROADCAST))
- goto out;
- if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
- goto out;
- rcu_read_lock();
- in_dev = __in_dev_get_rcu(rt->dst.dev);
- if (in_dev != NULL) {
- for_primary_ifa(in_dev) {
- if (ifa->ifa_broadcast == iph->daddr) {
- mask = ifa->ifa_mask;
- break;
- }
- } endfor_ifa(in_dev);
- }
- rcu_read_unlock();
- if (mask == 0)
- goto out;
- exp = nf_ct_expect_alloc(ct);
- if (exp == NULL)
- goto out;
- exp->tuple = ct->tuplehash[IP_CT_DIR_REPLY].tuple;
- exp->tuple.src.u.udp.port = help->helper->tuple.src.u.udp.port;
- exp->mask.src.u3.ip = mask;
- exp->mask.src.u.udp.port = htons(0xFFFF);
- exp->expectfn = NULL;
- exp->flags = NF_CT_EXPECT_PERMANENT;
- exp->class = NF_CT_EXPECT_CLASS_DEFAULT;
- exp->helper = NULL;
- nf_ct_expect_related(exp);
- nf_ct_expect_put(exp);
- nf_ct_refresh(ct, skb, timeout * HZ);
- out:
- return NF_ACCEPT;
- }
- EXPORT_SYMBOL_GPL(nf_conntrack_broadcast_help);
- MODULE_LICENSE("GPL");
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