132 lines
3.1 KiB
C
132 lines
3.1 KiB
C
/* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/types.h>
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#include <linux/ip.h>
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#include <linux/netfilter.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <net/route.h>
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#include <net/ip.h>
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#include <linux/netfilter_bridge.h>
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#include <linux/netfilter_ipv4.h>
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#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
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#if IS_ENABLED(CONFIG_NF_CONNTRACK)
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#include <net/netfilter/nf_conntrack.h>
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#endif
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#include <net/netfilter/nf_conntrack_zones.h>
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static int nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
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{
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int err;
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skb_orphan(skb);
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local_bh_disable();
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err = ip_defrag(skb, user);
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local_bh_enable();
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if (!err) {
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ip_send_check(ip_hdr(skb));
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skb->ignore_df = 1;
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}
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return err;
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}
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static enum ip_defrag_users nf_ct_defrag_user(unsigned int hooknum,
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struct sk_buff *skb)
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{
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u16 zone = NF_CT_DEFAULT_ZONE;
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#if IS_ENABLED(CONFIG_NF_CONNTRACK)
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if (skb->nfct)
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zone = nf_ct_zone((struct nf_conn *)skb->nfct);
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#endif
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#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
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if (skb->nf_bridge &&
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skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)
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return IP_DEFRAG_CONNTRACK_BRIDGE_IN + zone;
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#endif
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if (hooknum == NF_INET_PRE_ROUTING)
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return IP_DEFRAG_CONNTRACK_IN + zone;
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else
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return IP_DEFRAG_CONNTRACK_OUT + zone;
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}
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static unsigned int ipv4_conntrack_defrag(const struct nf_hook_ops *ops,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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struct sock *sk = skb->sk;
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struct inet_sock *inet = inet_sk(skb->sk);
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if (sk && (sk->sk_family == PF_INET) &&
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inet->nodefrag)
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return NF_ACCEPT;
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#if IS_ENABLED(CONFIG_NF_CONNTRACK)
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#if !IS_ENABLED(CONFIG_NF_NAT)
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/* Previously seen (loopback)? Ignore. Do this before
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fragment check. */
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if (skb->nfct && !nf_ct_is_template((struct nf_conn *)skb->nfct))
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return NF_ACCEPT;
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#endif
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#endif
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/* Gather fragments. */
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if (ip_is_fragment(ip_hdr(skb))) {
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enum ip_defrag_users user =
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nf_ct_defrag_user(ops->hooknum, skb);
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if (nf_ct_ipv4_gather_frags(skb, user))
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return NF_STOLEN;
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}
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return NF_ACCEPT;
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}
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static struct nf_hook_ops ipv4_defrag_ops[] = {
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{
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.hook = ipv4_conntrack_defrag,
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.owner = THIS_MODULE,
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.pf = NFPROTO_IPV4,
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.hooknum = NF_INET_PRE_ROUTING,
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.priority = NF_IP_PRI_CONNTRACK_DEFRAG,
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},
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{
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.hook = ipv4_conntrack_defrag,
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.owner = THIS_MODULE,
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.pf = NFPROTO_IPV4,
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.hooknum = NF_INET_LOCAL_OUT,
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.priority = NF_IP_PRI_CONNTRACK_DEFRAG,
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},
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};
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static int __init nf_defrag_init(void)
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{
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return nf_register_hooks(ipv4_defrag_ops, ARRAY_SIZE(ipv4_defrag_ops));
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}
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static void __exit nf_defrag_fini(void)
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{
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nf_unregister_hooks(ipv4_defrag_ops, ARRAY_SIZE(ipv4_defrag_ops));
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}
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void nf_defrag_ipv4_enable(void)
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{
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}
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EXPORT_SYMBOL_GPL(nf_defrag_ipv4_enable);
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module_init(nf_defrag_init);
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module_exit(nf_defrag_fini);
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MODULE_LICENSE("GPL");
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