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DEFINITIONS
This source file includes following definitions.
- ipv6_pkt_to_tuple
- ipv6_invert_tuple
- ipv6_print_tuple
- nf_ct_ipv6_skip_exthdr
- ipv6_get_l4proto
- ipv6_confirm
- ipv6_defrag
- __ipv6_conntrack_in
- ipv6_conntrack_in
- ipv6_conntrack_local
- ipv6_tuple_to_nlattr
- ipv6_nlattr_to_tuple
- nf_conntrack_l3proto_ipv6_init
- nf_conntrack_l3proto_ipv6_fini
/*
* Copyright (C)2004 USAGI/WIDE Project
*
* 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.
*
* Author:
* Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
*/
#include <linux/types.h>
#include <linux/ipv6.h>
#include <linux/in6.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/icmp.h>
#include <linux/sysctl.h>
#include <net/ipv6.h>
#include <net/inet_frag.h>
#include <linux/netfilter_ipv6.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_core.h>
static bool ipv6_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
struct nf_conntrack_tuple *tuple)
{
const u_int32_t *ap;
u_int32_t _addrs[8];
ap = skb_header_pointer(skb, nhoff + offsetof(struct ipv6hdr, saddr),
sizeof(_addrs), _addrs);
if (ap == NULL)
return false;
memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6));
memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6));
return true;
}
static bool ipv6_invert_tuple(struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_tuple *orig)
{
memcpy(tuple->src.u3.ip6, orig->dst.u3.ip6, sizeof(tuple->src.u3.ip6));
memcpy(tuple->dst.u3.ip6, orig->src.u3.ip6, sizeof(tuple->dst.u3.ip6));
return true;
}
static int ipv6_print_tuple(struct seq_file *s,
const struct nf_conntrack_tuple *tuple)
{
return seq_printf(s, "src=" NIP6_FMT " dst=" NIP6_FMT " ",
NIP6(*((struct in6_addr *)tuple->src.u3.ip6)),
NIP6(*((struct in6_addr *)tuple->dst.u3.ip6)));
}
/*
* Based on ipv6_skip_exthdr() in net/ipv6/exthdr.c
*
* This function parses (probably truncated) exthdr set "hdr"
* of length "len". "nexthdrp" initially points to some place,
* where type of the first header can be found.
*
* It skips all well-known exthdrs, and returns pointer to the start
* of unparsable area i.e. the first header with unknown type.
* if success, *nexthdr is updated by type/protocol of this header.
*
* NOTES: - it may return pointer pointing beyond end of packet,
* if the last recognized header is truncated in the middle.
* - if packet is truncated, so that all parsed headers are skipped,
* it returns -1.
* - if packet is fragmented, return pointer of the fragment header.
* - ESP is unparsable for now and considered like
* normal payload protocol.
* - Note also special handling of AUTH header. Thanks to IPsec wizards.
*/
static int nf_ct_ipv6_skip_exthdr(const struct sk_buff *skb, int start,
u8 *nexthdrp, int len)
{
u8 nexthdr = *nexthdrp;
while (ipv6_ext_hdr(nexthdr)) {
struct ipv6_opt_hdr hdr;
int hdrlen;
if (len < (int)sizeof(struct ipv6_opt_hdr))
return -1;
if (nexthdr == NEXTHDR_NONE)
break;
if (nexthdr == NEXTHDR_FRAGMENT)
break;
if (skb_copy_bits(skb, start, &hdr, sizeof(hdr)))
BUG();
if (nexthdr == NEXTHDR_AUTH)
hdrlen = (hdr.hdrlen+2)<<2;
else
hdrlen = ipv6_optlen(&hdr);
nexthdr = hdr.nexthdr;
len -= hdrlen;
start += hdrlen;
}
*nexthdrp = nexthdr;
return start;
}
static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
unsigned int *dataoff, u_int8_t *protonum)
{
unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
unsigned char pnum;
int protoff;
if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
&pnum, sizeof(pnum)) != 0) {
pr_debug("ip6_conntrack_core: can't get nexthdr\n");
return -NF_ACCEPT;
}
protoff = nf_ct_ipv6_skip_exthdr(skb, extoff, &pnum, skb->len - extoff);
/*
* (protoff == skb->len) mean that the packet doesn't have no data
* except of IPv6 & ext headers. but it's tracked anyway. - YK
*/
if ((protoff < 0) || (protoff > skb->len)) {
pr_debug("ip6_conntrack_core: can't find proto in pkt\n");
return -NF_ACCEPT;
}
*dataoff = protoff;
*protonum = pnum;
return NF_ACCEPT;
}
static unsigned int ipv6_confirm(unsigned int hooknum,
struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct nf_conn *ct;
const struct nf_conn_help *help;
const struct nf_conntrack_helper *helper;
enum ip_conntrack_info ctinfo;
unsigned int ret, protoff;
unsigned int extoff = (u8 *)(ipv6_hdr(skb) + 1) - skb->data;
unsigned char pnum = ipv6_hdr(skb)->nexthdr;
/* This is where we call the helper: as the packet goes out. */
ct = nf_ct_get(skb, &ctinfo);
if (!ct || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)
goto out;
help = nfct_help(ct);
if (!help)
goto out;
/* rcu_read_lock()ed by nf_hook_slow */
helper = rcu_dereference(help->helper);
if (!helper)
goto out;
protoff = nf_ct_ipv6_skip_exthdr(skb, extoff, &pnum,
skb->len - extoff);
if (protoff > skb->len || pnum == NEXTHDR_FRAGMENT) {
pr_debug("proto header not found\n");
return NF_ACCEPT;
}
ret = helper->help(skb, protoff, ct, ctinfo);
if (ret != NF_ACCEPT)
return ret;
out:
/* We've seen it coming out the other side: confirm it */
return nf_conntrack_confirm(skb);
}
static unsigned int ipv6_defrag(unsigned int hooknum,
struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
struct sk_buff *reasm;
/* Previously seen (loopback)? */
if (skb->nfct)
return NF_ACCEPT;
reasm = nf_ct_frag6_gather(skb);
/* queued */
if (reasm == NULL)
return NF_STOLEN;
/* error occured or not fragmented */
if (reasm == skb)
return NF_ACCEPT;
nf_ct_frag6_output(hooknum, reasm, (struct net_device *)in,
(struct net_device *)out, okfn);
return NF_STOLEN;
}
static unsigned int __ipv6_conntrack_in(struct net *net,
unsigned int hooknum,
struct sk_buff *skb,
int (*okfn)(struct sk_buff *))
{
struct sk_buff *reasm = skb->nfct_reasm;
/* This packet is fragmented and has reassembled packet. */
if (reasm) {
/* Reassembled packet isn't parsed yet ? */
if (!reasm->nfct) {
unsigned int ret;
ret = nf_conntrack_in(net, PF_INET6, hooknum, reasm);
if (ret != NF_ACCEPT)
return ret;
}
nf_conntrack_get(reasm->nfct);
skb->nfct = reasm->nfct;
skb->nfctinfo = reasm->nfctinfo;
return NF_ACCEPT;
}
return nf_conntrack_in(net, PF_INET6, hooknum, skb);
}
static unsigned int ipv6_conntrack_in(unsigned int hooknum,
struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
return __ipv6_conntrack_in(dev_net(in), hooknum, skb, okfn);
}
static unsigned int ipv6_conntrack_local(unsigned int hooknum,
struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *))
{
/* root is playing with raw sockets. */
if (skb->len < sizeof(struct ipv6hdr)) {
if (net_ratelimit())
printk("ipv6_conntrack_local: packet too short\n");
return NF_ACCEPT;
}
return __ipv6_conntrack_in(dev_net(out), hooknum, skb, okfn);
}
static struct nf_hook_ops ipv6_conntrack_ops[] __read_mostly = {
{
.hook = ipv6_defrag,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_INET_PRE_ROUTING,
.priority = NF_IP6_PRI_CONNTRACK_DEFRAG,
},
{
.hook = ipv6_conntrack_in,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_INET_PRE_ROUTING,
.priority = NF_IP6_PRI_CONNTRACK,
},
{
.hook = ipv6_conntrack_local,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_INET_LOCAL_OUT,
.priority = NF_IP6_PRI_CONNTRACK,
},
{
.hook = ipv6_defrag,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_INET_LOCAL_OUT,
.priority = NF_IP6_PRI_CONNTRACK_DEFRAG,
},
{
.hook = ipv6_confirm,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_INET_POST_ROUTING,
.priority = NF_IP6_PRI_LAST,
},
{
.hook = ipv6_confirm,
.owner = THIS_MODULE,
.pf = PF_INET6,
.hooknum = NF_INET_LOCAL_IN,
.priority = NF_IP6_PRI_LAST-1,
},
};
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_conntrack.h>
static int ipv6_tuple_to_nlattr(struct sk_buff *skb,
const struct nf_conntrack_tuple *tuple)
{
NLA_PUT(skb, CTA_IP_V6_SRC, sizeof(u_int32_t) * 4,
&tuple->src.u3.ip6);
NLA_PUT(skb, CTA_IP_V6_DST, sizeof(u_int32_t) * 4,
&tuple->dst.u3.ip6);
return 0;
nla_put_failure:
return -1;
}
static const struct nla_policy ipv6_nla_policy[CTA_IP_MAX+1] = {
[CTA_IP_V6_SRC] = { .len = sizeof(u_int32_t)*4 },
[CTA_IP_V6_DST] = { .len = sizeof(u_int32_t)*4 },
};
static int ipv6_nlattr_to_tuple(struct nlattr *tb[],
struct nf_conntrack_tuple *t)
{
if (!tb[CTA_IP_V6_SRC] || !tb[CTA_IP_V6_DST])
return -EINVAL;
memcpy(&t->src.u3.ip6, nla_data(tb[CTA_IP_V6_SRC]),
sizeof(u_int32_t) * 4);
memcpy(&t->dst.u3.ip6, nla_data(tb[CTA_IP_V6_DST]),
sizeof(u_int32_t) * 4);
return 0;
}
#endif
struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6 __read_mostly = {
.l3proto = PF_INET6,
.name = "ipv6",
.pkt_to_tuple = ipv6_pkt_to_tuple,
.invert_tuple = ipv6_invert_tuple,
.print_tuple = ipv6_print_tuple,
.get_l4proto = ipv6_get_l4proto,
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
.tuple_to_nlattr = ipv6_tuple_to_nlattr,
.nlattr_to_tuple = ipv6_nlattr_to_tuple,
.nla_policy = ipv6_nla_policy,
#endif
#ifdef CONFIG_SYSCTL
.ctl_table_path = nf_net_netfilter_sysctl_path,
.ctl_table = nf_ct_ipv6_sysctl_table,
#endif
.me = THIS_MODULE,
};
MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET6));
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Yasuyuki KOZAKAI @USAGI <yasuyuki.kozakai@toshiba.co.jp>");
static int __init nf_conntrack_l3proto_ipv6_init(void)
{
int ret = 0;
need_conntrack();
ret = nf_ct_frag6_init();
if (ret < 0) {
printk("nf_conntrack_ipv6: can't initialize frag6.\n");
return ret;
}
ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp6);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register tcp.\n");
goto cleanup_frag6;
}
ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp6);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register udp.\n");
goto cleanup_tcp;
}
ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmpv6);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register icmpv6.\n");
goto cleanup_udp;
}
ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv6);
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register ipv6\n");
goto cleanup_icmpv6;
}
ret = nf_register_hooks(ipv6_conntrack_ops,
ARRAY_SIZE(ipv6_conntrack_ops));
if (ret < 0) {
printk("nf_conntrack_ipv6: can't register pre-routing defrag "
"hook.\n");
goto cleanup_ipv6;
}
return ret;
cleanup_ipv6:
nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv6);
cleanup_icmpv6:
nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmpv6);
cleanup_udp:
nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp6);
cleanup_tcp:
nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp6);
cleanup_frag6:
nf_ct_frag6_cleanup();
return ret;
}
static void __exit nf_conntrack_l3proto_ipv6_fini(void)
{
synchronize_net();
nf_unregister_hooks(ipv6_conntrack_ops, ARRAY_SIZE(ipv6_conntrack_ops));
nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv6);
nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmpv6);
nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp6);
nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp6);
nf_ct_frag6_cleanup();
}
module_init(nf_conntrack_l3proto_ipv6_init);
module_exit(nf_conntrack_l3proto_ipv6_fini);