Commit ed13923f authored by Ido Schimmel's avatar Ido Schimmel Committed by David S. Miller
Browse files

ipv6: Add a sysctl to control multipath hash fields 



A subsequent patch will add a new multipath hash policy where the packet
fields used for multipath hash calculation are determined by user space.
This patch adds a sysctl that allows user space to set these fields.

The packet fields are represented using a bitmask and are common between
IPv4 and IPv6 to allow user space to use the same numbering across both
protocols. For example, to hash based on standard 5-tuple:

 # sysctl -w net.ipv6.fib_multipath_hash_fields=0x0037
 net.ipv6.fib_multipath_hash_fields = 0x0037

To avoid introducing holes in 'struct netns_sysctl_ipv6', move the
'bindv6only' field after the multipath hash fields.

The kernel rejects unknown fields, for example:

 # sysctl -w net.ipv6.fib_multipath_hash_fields=0x1000
 sysctl: setting key "net.ipv6.fib_multipath_hash_fields": Invalid argument

Signed-off-by: default avatarIdo Schimmel <idosch@nvidia.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b95b6e07

Documentation/networking/ip-sysctl.rst

+27 −0
Original line number Diff line number Diff line
@@ -1773,6 +1773,33 @@ fib_multipath_hash_policy - INTEGER 
	- 1 - Layer 4 (standard 5-tuple)

	- 2 - Layer 3 or inner Layer 3 if present



fib_multipath_hash_fields - UNSIGNED INTEGER

	When fib_multipath_hash_policy is set to 3 (custom multipath hash), the

	fields used for multipath hash calculation are determined by this

	sysctl.



	This value is a bitmask which enables various fields for multipath hash

	calculation.



	Possible fields are:



	====== ============================

	0x0001 Source IP address

	0x0002 Destination IP address

	0x0004 IP protocol

	0x0008 Flow Label

	0x0010 Source port

	0x0020 Destination port

	0x0040 Inner source IP address

	0x0080 Inner destination IP address

	0x0100 Inner IP protocol

	0x0200 Inner Flow Label

	0x0400 Inner source port

	0x0800 Inner destination port

	====== ============================



	Default: 0x0007 (source IP, destination IP and IP protocol)



anycast_src_echo_reply - BOOLEAN

	Controls the use of anycast addresses as source addresses for ICMPv6

	echo reply

include/net/ipv6.h

+8 −0
Original line number Diff line number Diff line
@@ -926,11 +926,19 @@ static inline int ip6_multipath_hash_policy(const struct net *net) 
{

	return net->ipv6.sysctl.multipath_hash_policy;

}

static inline u32 ip6_multipath_hash_fields(const struct net *net)

{

	return net->ipv6.sysctl.multipath_hash_fields;

}

#else

static inline int ip6_multipath_hash_policy(const struct net *net)

{

	return 0;

}

static inline u32 ip6_multipath_hash_fields(const struct net *net)

{

	return 0;

}

#endif



/*

include/net/netns/ipv6.h

+2 −1
Original line number Diff line number Diff line
@@ -28,8 +28,9 @@ struct netns_sysctl_ipv6 { 
	int ip6_rt_gc_elasticity;

	int ip6_rt_mtu_expires;

	int ip6_rt_min_advmss;

	u8 bindv6only;

	u32 multipath_hash_fields;

	u8 multipath_hash_policy;

	u8 bindv6only;

	u8 flowlabel_consistency;

	u8 auto_flowlabels;

	int icmpv6_time;

net/ipv6/ip6_fib.c

+5 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 
#include <net/lwtunnel.h>

#include <net/fib_notifier.h>



#include <net/ip_fib.h>

#include <net/ip6_fib.h>

#include <net/ip6_route.h>
@@ -2355,6 +2356,10 @@ static int __net_init fib6_net_init(struct net *net) 
	if (err)

		return err;



	/* Default to 3-tuple */

	net->ipv6.sysctl.multipath_hash_fields =

		FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK;



	spin_lock_init(&net->ipv6.fib6_gc_lock);

	rwlock_init(&net->ipv6.fib6_walker_lock);

	INIT_LIST_HEAD(&net->ipv6.fib6_walkers);

net/ipv6/sysctl_net_ipv6.c

+12 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <net/addrconf.h>

#include <net/inet_frag.h>

#include <net/netevent.h>

#include <net/ip_fib.h>

#ifdef CONFIG_NETLABEL

#include <net/calipso.h>

#endif
@@ -24,6 +25,8 @@ 
static int two = 2;

static int flowlabel_reflect_max = 0x7;

static int auto_flowlabels_max = IP6_AUTO_FLOW_LABEL_MAX;

static u32 rt6_multipath_hash_fields_all_mask =

	FIB_MULTIPATH_HASH_FIELD_ALL_MASK;



static int proc_rt6_multipath_hash_policy(struct ctl_table *table, int write,

					  void *buffer, size_t *lenp, loff_t *ppos)
@@ -151,6 +154,15 @@ static struct ctl_table ipv6_table_template[] = { 
		.extra1		= SYSCTL_ZERO,

		.extra2		= &two,

	},

	{

		.procname	= "fib_multipath_hash_fields",

		.data		= &init_net.ipv6.sysctl.multipath_hash_fields,

		.maxlen		= sizeof(u32),

		.mode		= 0644,

		.proc_handler	= proc_douintvec_minmax,

		.extra1		= SYSCTL_ONE,

		.extra2		= &rt6_multipath_hash_fields_all_mask,

	},

	{

		.procname	= "seg6_flowlabel",

		.data		= &init_net.ipv6.sysctl.seg6_flowlabel,