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Date: Sat, 5 Mar 2016 00:39:20 +0300
From: Cyrill Gorcunov <gorcunov@...il.com>
To: NETDEV <netdev@...r.kernel.org>
Cc: Solar Designer <solar@...nwall.com>,
Vasily Averin <vvs@...tuozzo.com>,
Andrey Vagin <avagin@...tuozzo.com>,
Pavel Emelianov <xemul@...tuozzo.com>,
Vladimir Davydov <vdavydov@...tuozzo.com>,
Konstantin Khorenko <khorenko@...tuozzo.com>,
David Miller <davem@...emloft.net>,
Eric Dumazet <eric.dumazet@...il.com>
Subject: [RFC] net: ipv4 -- Introduce ifa limit per net
Currenlty all the kernels (including vanilla) free ifa
list under rtln_lock() taken which takes a huge time
to release all entries when we stop the container.
Moreover it's allowed to create unlimited number
of addresses from inside of net-namespace if
CAP-NET_ADMIN granted (which is common for containers).
Lets introduce per-net limit (4096 by default)
of addresses, which can be tuned up via sysfs
entry /proc/sys/net/ipv4/ifa_limit.
Reported-by: Solar Designer <solar@...nwall.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@...tuozzo.com>
CC: Vasily Averin <vvs@...tuozzo.com>
CC: Andrey Vagin <avagin@...tuozzo.com>
CC: Pavel Emelianov <xemul@...tuozzo.com>
CC: Vladimir Davydov <vdavydov@...tuozzo.com>
CC: Konstantin Khorenko <khorenko@...tuozzo.com>
CC: David Miller <davem@...emloft.net>
CC: Eric Dumazet <eric.dumazet@...il.com>
---
Please share the idea if there some more elegant way exist
to fix this problem, maybe I miss something obvious. Thanks!
include/net/netns/ipv4.h | 3 +++
net/ipv4/devinet.c | 34 +++++++++++++++++++---------------
net/ipv4/sysctl_net_ipv4.c | 8 ++++++++
3 files changed, 30 insertions(+), 15 deletions(-)
Index: linux-ml.git/include/net/netns/ipv4.h
===================================================================
--- linux-ml.git.orig/include/net/netns/ipv4.h
+++ linux-ml.git/include/net/netns/ipv4.h
@@ -77,6 +77,8 @@ struct netns_ipv4 {
struct local_ports ip_local_ports;
+ int sysctl_ifa_limit;
+
int sysctl_tcp_ecn;
int sysctl_tcp_ecn_fallback;
@@ -101,6 +103,7 @@ struct netns_ipv4 {
struct ping_group_range ping_group_range;
atomic_t dev_addr_genid;
+ atomic_t ifa_nr;
#ifdef CONFIG_SYSCTL
unsigned long *sysctl_local_reserved_ports;
Index: linux-ml.git/net/ipv4/devinet.c
===================================================================
--- linux-ml.git.orig/net/ipv4/devinet.c
+++ linux-ml.git/net/ipv4/devinet.c
@@ -194,8 +194,11 @@ static void devinet_sysctl_unregister(st
/* Locks all the inet devices. */
-static struct in_ifaddr *inet_alloc_ifa(void)
+static struct in_ifaddr *inet_alloc_ifa(struct net *net)
{
+ if (atomic_add_return(1, &net->ipv4.ifa_nr) >
+ net->ipv4.sysctl_ifa_limit)
+ return NULL;
return kzalloc(sizeof(struct in_ifaddr), GFP_KERNEL);
}
@@ -207,8 +210,9 @@ static void inet_rcu_free_ifa(struct rcu
kfree(ifa);
}
-static void inet_free_ifa(struct in_ifaddr *ifa)
+static void inet_free_ifa(struct net *net, struct in_ifaddr *ifa)
{
+ atomic_dec(&net->ipv4.ifa_nr);
call_rcu(&ifa->rcu_head, inet_rcu_free_ifa);
}
@@ -296,7 +300,7 @@ static void inetdev_destroy(struct in_de
while ((ifa = in_dev->ifa_list) != NULL) {
inet_del_ifa(in_dev, &in_dev->ifa_list, 0);
- inet_free_ifa(ifa);
+ inet_free_ifa(dev_net(dev), ifa);
}
RCU_INIT_POINTER(dev->ip_ptr, NULL);
@@ -361,7 +365,7 @@ static void __inet_del_ifa(struct in_dev
rtmsg_ifa(RTM_DELADDR, ifa, nlh, portid);
blocking_notifier_call_chain(&inetaddr_chain,
NETDEV_DOWN, ifa);
- inet_free_ifa(ifa);
+ inet_free_ifa(dev_net(in_dev->dev), ifa);
} else {
promote = ifa;
break;
@@ -420,7 +424,7 @@ static void __inet_del_ifa(struct in_dev
}
if (destroy)
- inet_free_ifa(ifa1);
+ inet_free_ifa(dev_net(in_dev->dev), ifa1);
}
static void inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
@@ -442,7 +446,7 @@ static int __inet_insert_ifa(struct in_i
ASSERT_RTNL();
if (!ifa->ifa_local) {
- inet_free_ifa(ifa);
+ inet_free_ifa(dev_net(in_dev->dev), ifa);
return 0;
}
@@ -457,11 +461,11 @@ static int __inet_insert_ifa(struct in_i
if (ifa1->ifa_mask == ifa->ifa_mask &&
inet_ifa_match(ifa1->ifa_address, ifa)) {
if (ifa1->ifa_local == ifa->ifa_local) {
- inet_free_ifa(ifa);
+ inet_free_ifa(dev_net(in_dev->dev), ifa);
return -EEXIST;
}
if (ifa1->ifa_scope != ifa->ifa_scope) {
- inet_free_ifa(ifa);
+ inet_free_ifa(dev_net(in_dev->dev), ifa);
return -EINVAL;
}
ifa->ifa_flags |= IFA_F_SECONDARY;
@@ -502,7 +506,7 @@ static int inet_set_ifa(struct net_devic
ASSERT_RTNL();
if (!in_dev) {
- inet_free_ifa(ifa);
+ inet_free_ifa(dev_net(dev), ifa);
return -ENOBUFS;
}
ipv4_devconf_setall(in_dev);
@@ -768,7 +772,7 @@ static struct in_ifaddr *rtm_to_ifaddr(s
if (!in_dev)
goto errout;
- ifa = inet_alloc_ifa();
+ ifa = inet_alloc_ifa(net);
if (!ifa)
/*
* A potential indev allocation can be left alive, it stays
@@ -817,7 +821,7 @@ static struct in_ifaddr *rtm_to_ifaddr(s
return ifa;
errout_free:
- inet_free_ifa(ifa);
+ inet_free_ifa(net, ifa);
errout:
return ERR_PTR(err);
}
@@ -865,13 +869,13 @@ static int inet_rtm_newaddr(struct sk_bu
true, ifa);
if (ret < 0) {
- inet_free_ifa(ifa);
+ inet_free_ifa(net, ifa);
return ret;
}
}
return __inet_insert_ifa(ifa, nlh, NETLINK_CB(skb).portid);
} else {
- inet_free_ifa(ifa);
+ inet_free_ifa(net, ifa);
if (nlh->nlmsg_flags & NLM_F_EXCL ||
!(nlh->nlmsg_flags & NLM_F_REPLACE))
@@ -1055,7 +1059,7 @@ int devinet_ioctl(struct net *net, unsig
if (!ifa) {
ret = -ENOBUFS;
- ifa = inet_alloc_ifa();
+ ifa = inet_alloc_ifa(net);
if (!ifa)
break;
INIT_HLIST_NODE(&ifa->hash);
@@ -1408,7 +1412,7 @@ static int inetdev_event(struct notifier
if (!inetdev_valid_mtu(dev->mtu))
break;
if (dev->flags & IFF_LOOPBACK) {
- struct in_ifaddr *ifa = inet_alloc_ifa();
+ struct in_ifaddr *ifa = inet_alloc_ifa(dev_net(dev));
if (ifa) {
INIT_HLIST_NODE(&ifa->hash);
Index: linux-ml.git/net/ipv4/sysctl_net_ipv4.c
===================================================================
--- linux-ml.git.orig/net/ipv4/sysctl_net_ipv4.c
+++ linux-ml.git/net/ipv4/sysctl_net_ipv4.c
@@ -960,6 +960,13 @@ static struct ctl_table ipv4_net_table[]
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
+ {
+ .procname = "ifa_limit",
+ .data = &init_net.ipv4.sysctl_ifa_limit,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
{ }
};
@@ -988,6 +995,7 @@ static __net_init int ipv4_sysctl_init_n
if (!net->ipv4.sysctl_local_reserved_ports)
goto err_ports;
+ net->ipv4.sysctl_ifa_limit = 4096;
return 0;
err_ports:
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