diff options
Diffstat (limited to 'net/ipv4/netfilter/nf_defrag_ipv4.c')
-rw-r--r-- | net/ipv4/netfilter/nf_defrag_ipv4.c | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/nf_defrag_ipv4.c b/net/ipv4/netfilter/nf_defrag_ipv4.c new file mode 100644 index 000000000000..aa2c50a180f7 --- /dev/null +++ b/net/ipv4/netfilter/nf_defrag_ipv4.c @@ -0,0 +1,96 @@ +/* (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_ipv4.h> +#include <net/netfilter/ipv4/nf_defrag_ipv4.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 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) + /* Previously seen (loopback)? Ignore. Do this before + fragment check. */ + if (skb->nfct) + return NF_ACCEPT; +#endif + + /* Gather fragments. */ + if (ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)) { + if (nf_ct_ipv4_gather_frags(skb, + hooknum == NF_INET_PRE_ROUTING ? + IP_DEFRAG_CONNTRACK_IN : + IP_DEFRAG_CONNTRACK_OUT)) + 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"); |