![Yasuyuki Kozakai](/assets/img/avatar_default.png)
The existing connection tracking subsystem in netfilter can only handle ipv4. There were basically two choices present to add connection tracking support for ipv6. We could either duplicate all of the ipv4 connection tracking code into an ipv6 counterpart, or (the choice taken by these patches) we could design a generic layer that could handle both ipv4 and ipv6 and thus requiring only one sub-protocol (TCP, UDP, etc.) connection tracking helper module to be written. In fact nf_conntrack is capable of working with any layer 3 protocol. The existing ipv4 specific conntrack code could also not deal with the pecularities of doing connection tracking on ipv6, which is also cured here. For example, these issues include: 1) ICMPv6 handling, which is used for neighbour discovery in ipv6 thus some messages such as these should not participate in connection tracking since effectively they are like ARP messages 2) fragmentation must be handled differently in ipv6, because the simplistic "defrag, connection track and NAT, refrag" (which the existing ipv4 connection tracking does) approach simply isn't feasible in ipv6 3) ipv6 extension header parsing must occur at the correct spots before and after connection tracking decisions, and there were no provisions for this in the existing connection tracking design 4) ipv6 has no need for stateful NAT The ipv4 specific conntrack layer is kept around, until all of the ipv4 specific conntrack helpers are ported over to nf_conntrack and it is feature complete. Once that occurs, the old conntrack stuff will get placed into the feature-removal-schedule and we will fully kill it off 6 months later. Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
79 lines
2.1 KiB
C
79 lines
2.1 KiB
C
#ifndef __LINUX_IP6_NETFILTER_H
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#define __LINUX_IP6_NETFILTER_H
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/* IPv6-specific defines for netfilter.
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* (C)1998 Rusty Russell -- This code is GPL.
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* (C)1999 David Jeffery
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* this header was blatantly ripped from netfilter_ipv4.h
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* it's amazing what adding a bunch of 6s can do =8^)
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*/
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#include <linux/netfilter.h>
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/* only for userspace compatibility */
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#ifndef __KERNEL__
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/* IP Cache bits. */
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/* Src IP address. */
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#define NFC_IP6_SRC 0x0001
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/* Dest IP address. */
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#define NFC_IP6_DST 0x0002
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/* Input device. */
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#define NFC_IP6_IF_IN 0x0004
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/* Output device. */
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#define NFC_IP6_IF_OUT 0x0008
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/* TOS. */
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#define NFC_IP6_TOS 0x0010
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/* Protocol. */
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#define NFC_IP6_PROTO 0x0020
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/* IP options. */
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#define NFC_IP6_OPTIONS 0x0040
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/* Frag & flags. */
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#define NFC_IP6_FRAG 0x0080
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/* Per-protocol information: only matters if proto match. */
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/* TCP flags. */
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#define NFC_IP6_TCPFLAGS 0x0100
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/* Source port. */
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#define NFC_IP6_SRC_PT 0x0200
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/* Dest port. */
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#define NFC_IP6_DST_PT 0x0400
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/* Something else about the proto */
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#define NFC_IP6_PROTO_UNKNOWN 0x2000
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#endif /* ! __KERNEL__ */
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/* IP6 Hooks */
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/* After promisc drops, checksum checks. */
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#define NF_IP6_PRE_ROUTING 0
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/* If the packet is destined for this box. */
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#define NF_IP6_LOCAL_IN 1
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/* If the packet is destined for another interface. */
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#define NF_IP6_FORWARD 2
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/* Packets coming from a local process. */
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#define NF_IP6_LOCAL_OUT 3
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/* Packets about to hit the wire. */
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#define NF_IP6_POST_ROUTING 4
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#define NF_IP6_NUMHOOKS 5
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enum nf_ip6_hook_priorities {
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NF_IP6_PRI_FIRST = INT_MIN,
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NF_IP6_PRI_CONNTRACK_DEFRAG = -400,
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NF_IP6_PRI_SELINUX_FIRST = -225,
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NF_IP6_PRI_CONNTRACK = -200,
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NF_IP6_PRI_BRIDGE_SABOTAGE_FORWARD = -175,
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NF_IP6_PRI_MANGLE = -150,
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NF_IP6_PRI_NAT_DST = -100,
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NF_IP6_PRI_BRIDGE_SABOTAGE_LOCAL_OUT = -50,
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NF_IP6_PRI_FILTER = 0,
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NF_IP6_PRI_NAT_SRC = 100,
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NF_IP6_PRI_SELINUX_LAST = 225,
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NF_IP6_PRI_LAST = INT_MAX,
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};
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extern int ipv6_netfilter_init(void);
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extern void ipv6_netfilter_fini(void);
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#endif /*__LINUX_IP6_NETFILTER_H*/
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