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net/ipv6: Add support for path selection using hash of 5-tuple 

Some operators prefer IPv6 path selection to use a standard 5-tuple
hash rather than just an L3 hash with the flow the label. To that end
add support to IPv6 for multipath hash policy similar to bf4e0a3db9
("net: ipv4: add support for ECMP hash policy choice"). The default
is still L3 which covers source and destination addresses along with
flow label and IPv6 protocol.

Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Tested-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2018-03-02 08:32:18 -08:00 committed by David S. Miller
parent b75cc8f90f
commit b4bac172e9
7 changed files with 91 additions and 19 deletions
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7
Documentation/networking/ip-sysctl.txt
View File

@ -1363,6 +1363,13 @@ flowlabel_reflect - BOOLEAN
FALSE: disabled
Default: FALSE
fib_multipath_hash_policy - INTEGER
Controls which hash policy to use for multipath routes.
Default: 0 (Layer 3)
Possible values:
0 - Layer 3 (source and destination addresses plus flow label)
1 - Layer 4 (standard 5-tuple)
anycast_src_echo_reply - BOOLEAN
Controls the use of anycast addresses as source addresses for ICMPv6
echo reply

4
include/net/ip6_route.h
View File

@ -130,8 +130,8 @@ static inline int ip6_route_get_saddr(struct net *net, struct rt6_info *rt,
struct rt6_info *rt6_lookup(struct net *net, const struct in6_addr *daddr,
const struct in6_addr *saddr, int oif,
const struct sk_buff *skb, int flags);
u32 rt6_multipath_hash(const struct flowi6 *fl6, const struct sk_buff *skb,
struct flow_keys *hkeys);
u32 rt6_multipath_hash(const struct net *net, const struct flowi6 *fl6,
const struct sk_buff *skb, struct flow_keys *hkeys);
struct dst_entry *icmp6_dst_alloc(struct net_device *dev, struct flowi6 *fl6);

1
include/net/netevent.h
View File

@ -27,6 +27,7 @@ enum netevent_notif_type {
NETEVENT_REDIRECT, /* arg is struct netevent_redirect ptr */
NETEVENT_DELAY_PROBE_TIME_UPDATE, /* arg is struct neigh_parms ptr */
NETEVENT_IPV4_MPATH_HASH_UPDATE, /* arg is struct net ptr */
NETEVENT_IPV6_MPATH_HASH_UPDATE, /* arg is struct net ptr */
};
int register_netevent_notifier(struct notifier_block *nb);

1
include/net/netns/ipv6.h
View File

@ -28,6 +28,7 @@ struct netns_sysctl_ipv6 {
int ip6_rt_gc_elasticity;
int ip6_rt_mtu_expires;
int ip6_rt_min_advmss;
int multipath_hash_policy;
int flowlabel_consistency;
int auto_flowlabels;
int icmpv6_time;

2
net/ipv6/icmp.c
View File

@ -522,7 +522,7 @@ static void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
fl6.fl6_icmp_type = type;
fl6.fl6_icmp_code = code;
fl6.flowi6_uid = sock_net_uid(net, NULL);
fl6.mp_hash = rt6_multipath_hash(&fl6, skb, NULL);
fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, NULL);
security_skb_classify_flow(skb, flowi6_to_flowi(&fl6));
sk = icmpv6_xmit_lock(net);

50
net/ipv6/route.c
View File

@ -450,7 +450,8 @@ static bool rt6_check_expired(const struct rt6_info *rt)
return false;
}
static struct rt6_info *rt6_multipath_select(struct rt6_info *match,
static struct rt6_info *rt6_multipath_select(const struct net *net,
struct rt6_info *match,
struct flowi6 *fl6, int oif,
const struct sk_buff *skb,
int strict)
@ -461,7 +462,7 @@ static struct rt6_info *rt6_multipath_select(struct rt6_info *match,
* case it will always be non-zero. Otherwise now is the time to do it.
*/
if (!fl6->mp_hash)
fl6->mp_hash = rt6_multipath_hash(fl6, skb, NULL);
fl6->mp_hash = rt6_multipath_hash(net, fl6, skb, NULL);
if (fl6->mp_hash <= atomic_read(&match->rt6i_nh_upper_bound))
return match;
@ -932,7 +933,7 @@ static struct rt6_info *ip6_pol_route_lookup(struct net *net,
rt = rt6_device_match(net, rt, &fl6->saddr,
fl6->flowi6_oif, flags);
if (rt->rt6i_nsiblings && fl6->flowi6_oif == 0)
rt = rt6_multipath_select(rt, fl6, fl6->flowi6_oif,
rt = rt6_multipath_select(net, rt, fl6, fl6->flowi6_oif,
skb, flags);
}
if (rt == net->ipv6.ip6_null_entry) {
@ -1674,7 +1675,7 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
redo_rt6_select:
rt = rt6_select(net, fn, oif, strict);
if (rt->rt6i_nsiblings)
rt = rt6_multipath_select(rt, fl6, oif, skb, strict);
rt = rt6_multipath_select(net, rt, fl6, oif, skb, strict);
if (rt == net->ipv6.ip6_null_entry) {
fn = fib6_backtrack(fn, &fl6->saddr);
if (fn)
@ -1839,12 +1840,14 @@ static void ip6_multipath_l3_keys(const struct sk_buff *skb,
}
/* if skb is set it will be used and fl6 can be NULL */
u32 rt6_multipath_hash(const struct flowi6 *fl6, const struct sk_buff *skb,
struct flow_keys *flkeys)
u32 rt6_multipath_hash(const struct net *net, const struct flowi6 *fl6,
const struct sk_buff *skb, struct flow_keys *flkeys)
{
struct flow_keys hash_keys;
u32 mhash;
switch (net->ipv6.sysctl.multipath_hash_policy) {
case 0:
memset(&hash_keys, 0, sizeof(hash_keys));
hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
if (skb) {
@ -1855,6 +1858,39 @@ u32 rt6_multipath_hash(const struct flowi6 *fl6, const struct sk_buff *skb,
hash_keys.tags.flow_label = (__force u32)fl6->flowlabel;
hash_keys.basic.ip_proto = fl6->flowi6_proto;
}
break;
case 1:
if (skb) {
unsigned int flag = FLOW_DISSECTOR_F_STOP_AT_ENCAP;
struct flow_keys keys;
/* short-circuit if we already have L4 hash present */
if (skb->l4_hash)
return skb_get_hash_raw(skb) >> 1;
memset(&hash_keys, 0, sizeof(hash_keys));
if (!flkeys) {
skb_flow_dissect_flow_keys(skb, &keys, flag);
flkeys = &keys;
}
hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
hash_keys.addrs.v6addrs.src = flkeys->addrs.v6addrs.src;
hash_keys.addrs.v6addrs.dst = flkeys->addrs.v6addrs.dst;
hash_keys.ports.src = flkeys->ports.src;
hash_keys.ports.dst = flkeys->ports.dst;
hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
} else {
memset(&hash_keys, 0, sizeof(hash_keys));
hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
hash_keys.addrs.v6addrs.src = fl6->saddr;
hash_keys.addrs.v6addrs.dst = fl6->daddr;
hash_keys.ports.src = fl6->fl6_sport;
hash_keys.ports.dst = fl6->fl6_dport;
hash_keys.basic.ip_proto = fl6->flowi6_proto;
}
break;
}
mhash = flow_hash_from_keys(&hash_keys);
return mhash >> 1;
@ -1884,7 +1920,7 @@ void ip6_route_input(struct sk_buff *skb)
flkeys = &_flkeys;
if (unlikely(fl6.flowi6_proto == IPPROTO_ICMPV6))
fl6.mp_hash = rt6_multipath_hash(&fl6, skb, flkeys);
fl6.mp_hash = rt6_multipath_hash(net, &fl6, skb, flkeys);
skb_dst_drop(skb);
skb_dst_set(skb,
ip6_route_input_lookup(net, skb->dev, &fl6, skb, flags));

27
net/ipv6/sysctl_net_ipv6.c
View File

@ -16,14 +16,31 @@
#include <net/ipv6.h>
#include <net/addrconf.h>
#include <net/inet_frag.h>
#include <net/netevent.h>
#ifdef CONFIG_NETLABEL
#include <net/calipso.h>
#endif
static int zero;
static int one = 1;
static int auto_flowlabels_min;
static int auto_flowlabels_max = IP6_AUTO_FLOW_LABEL_MAX;
static int proc_rt6_multipath_hash_policy(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
{
struct net *net;
int ret;
net = container_of(table->data, struct net,
ipv6.sysctl.multipath_hash_policy);
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (write && ret == 0)
call_netevent_notifiers(NETEVENT_IPV6_MPATH_HASH_UPDATE, net);
return ret;
}
static struct ctl_table ipv6_table_template[] = {
{
@ -126,6 +143,15 @@ static struct ctl_table ipv6_table_template[] = {
.mode = 0644,
.proc_handler = proc_dointvec
},
{
.procname = "fib_multipath_hash_policy",
.data = &init_net.ipv6.sysctl.multipath_hash_policy,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_rt6_multipath_hash_policy,
.extra1 = &zero,
.extra2 = &one,
},
{ }
};
@ -190,6 +216,7 @@ static int __net_init ipv6_sysctl_net_init(struct net *net)
ipv6_table[11].data = &net->ipv6.sysctl.max_hbh_opts_cnt;
ipv6_table[12].data = &net->ipv6.sysctl.max_dst_opts_len;
ipv6_table[13].data = &net->ipv6.sysctl.max_hbh_opts_len;
ipv6_table[14].data = &net->ipv6.sysctl.multipath_hash_policy,
ipv6_route_table = ipv6_route_sysctl_init(net);
if (!ipv6_route_table)