/net/ipv4/netfilter/nf_defrag_ipv4.c
https://bitbucket.org/abioy/linux · C · 121 lines · 93 code · 17 blank · 11 comment · 13 complexity · 65ffe94947dc1c3173c99ebbe275609d MD5 · raw file
- /* (C) 1999-2001 Paul `Rusty' Russell
- * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
- #include <linux/types.h>
- #include <linux/ip.h>
- #include <linux/netfilter.h>
- #include <linux/module.h>
- #include <linux/skbuff.h>
- #include <net/route.h>
- #include <net/ip.h>
- #include <linux/netfilter_bridge.h>
- #include <linux/netfilter_ipv4.h>
- #include <net/netfilter/ipv4/nf_defrag_ipv4.h>
- #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
- #include <net/netfilter/nf_conntrack.h>
- #endif
- #include <net/netfilter/nf_conntrack_zones.h>
- /* Returns new sk_buff, or NULL */
- static int nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
- {
- int err;
- skb_orphan(skb);
- local_bh_disable();
- err = ip_defrag(skb, user);
- local_bh_enable();
- if (!err)
- ip_send_check(ip_hdr(skb));
- return err;
- }
- static enum ip_defrag_users nf_ct_defrag_user(unsigned int hooknum,
- struct sk_buff *skb)
- {
- u16 zone = NF_CT_DEFAULT_ZONE;
- #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
- if (skb->nfct)
- zone = nf_ct_zone((struct nf_conn *)skb->nfct);
- #endif
- #ifdef CONFIG_BRIDGE_NETFILTER
- if (skb->nf_bridge &&
- skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)
- return IP_DEFRAG_CONNTRACK_BRIDGE_IN + zone;
- #endif
- if (hooknum == NF_INET_PRE_ROUTING)
- return IP_DEFRAG_CONNTRACK_IN + zone;
- else
- return IP_DEFRAG_CONNTRACK_OUT + zone;
- }
- static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
- struct sk_buff *skb,
- const struct net_device *in,
- const struct net_device *out,
- int (*okfn)(struct sk_buff *))
- {
- #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
- #if !defined(CONFIG_NF_NAT) && !defined(CONFIG_NF_NAT_MODULE)
- /* Previously seen (loopback)? Ignore. Do this before
- fragment check. */
- if (skb->nfct && !nf_ct_is_template((struct nf_conn *)skb->nfct))
- return NF_ACCEPT;
- #endif
- #endif
- /* Gather fragments. */
- if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) {
- enum ip_defrag_users user = nf_ct_defrag_user(hooknum, skb);
- if (nf_ct_ipv4_gather_frags(skb, user))
- return NF_STOLEN;
- }
- return NF_ACCEPT;
- }
- static struct nf_hook_ops ipv4_defrag_ops[] = {
- {
- .hook = ipv4_conntrack_defrag,
- .owner = THIS_MODULE,
- .pf = PF_INET,
- .hooknum = NF_INET_PRE_ROUTING,
- .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
- },
- {
- .hook = ipv4_conntrack_defrag,
- .owner = THIS_MODULE,
- .pf = PF_INET,
- .hooknum = NF_INET_LOCAL_OUT,
- .priority = NF_IP_PRI_CONNTRACK_DEFRAG,
- },
- };
- static int __init nf_defrag_init(void)
- {
- return nf_register_hooks(ipv4_defrag_ops, ARRAY_SIZE(ipv4_defrag_ops));
- }
- static void __exit nf_defrag_fini(void)
- {
- nf_unregister_hooks(ipv4_defrag_ops, ARRAY_SIZE(ipv4_defrag_ops));
- }
- void nf_defrag_ipv4_enable(void)
- {
- }
- EXPORT_SYMBOL_GPL(nf_defrag_ipv4_enable);
- module_init(nf_defrag_init);
- module_exit(nf_defrag_fini);
- MODULE_LICENSE("GPL");