From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: [PATCH] net: ipv6: Make address flushing on ifdown optional - v2 Date: Wed, 28 Jan 2015 21:01:05 -0700 Message-ID: <1422504065-17445-1-git-send-email-dsahern@gmail.com> Cc: David Ahern , Hannes Frederic Sowa To: netdev@vger.kernel.org Return-path: Received: from mail-ie0-f177.google.com ([209.85.223.177]:64198 "EHLO mail-ie0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752544AbbA2ECS (ORCPT ); Wed, 28 Jan 2015 23:02:18 -0500 Received: by mail-ie0-f177.google.com with SMTP id vy18so28758755iec.8 for ; Wed, 28 Jan 2015 20:02:18 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: Currently, all ipv6 addresses are flushed when the interface is configured down, even static address: [root@f20 ~]# ip -6 addr add dev eth1 2000:11:1:1::1/64 [root@f20 ~]# ip addr show dev eth1 3: eth1: mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether 02:04:11:22:33:01 brd ff:ff:ff:ff:ff:ff inet6 2000:11:1:1::1/64 scope global tentative valid_lft forever preferred_lft forever [root@f20 ~]# ip link set dev eth1 up [root@f20 ~]# ip link set dev eth1 down [root@f20 ~]# ip addr show dev eth1 3: eth1: mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000 link/ether 02:04:11:22:33:01 brd ff:ff:ff:ff:ff:ff Add a new sysctl to make this behavior optional. The new setting defaults to flush all addresses to maintain backwards compatibility. When the setting is reset static addresses are not flushed: [root@f20 ~]# echo 0 > /proc/sys/net/ipv6/conf/eth1/flush_addr_on_down [root@f20 ~]# ip -6 addr add dev eth1 2000:11:1:1::1/64 [root@f20 ~]# ip addr show dev eth1 3: eth1: mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000 link/ether 02:04:11:22:33:01 brd ff:ff:ff:ff:ff:ff inet6 2000:11:1:1::1/64 scope global tentative valid_lft forever preferred_lft forever [root@f20 ~]# ip link set dev eth1 up [root@f20 ~]# ip link set dev eth1 down [root@f20 ~]# ip addr show dev eth1 3: eth1: mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000 link/ether 02:04:11:22:33:01 brd ff:ff:ff:ff:ff:ff inet6 2000:11:1:1::1/64 scope global valid_lft forever preferred_lft forever inet6 fe80::4:11ff:fe22:3301/64 scope link valid_lft forever preferred_lft forever v2: - only keep static addresses as suggested by Hannes - added new managed flag to track configured addresses - on ifdown do not remove from configured address from inet6_addr_lst - on ifdown reset the TENTATIVE flag and set state to DAD so that DAD is redone when link is brought up again Suggested-by: Hannes Frederic Sowa Signed-off-by: David Ahern Cc: Hannes Frederic Sowa Signed-off-by: David Ahern --- include/linux/ipv6.h | 1 + include/net/if_inet6.h | 1 + include/uapi/linux/ipv6.h | 1 + net/ipv6/addrconf.c | 55 ++++++++++++++++++++++++++++++++++++++--------- 4 files changed, 48 insertions(+), 10 deletions(-) diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index 2805062c013f..b91b7c8be023 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -53,6 +53,7 @@ struct ipv6_devconf { __s32 ndisc_notify; __s32 suppress_frag_ndisc; __s32 accept_ra_mtu; + __s32 flush_addr_on_down; void *sysctl; }; diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h index 98e5f9578f86..3b6323111f77 100644 --- a/include/net/if_inet6.h +++ b/include/net/if_inet6.h @@ -72,6 +72,7 @@ struct inet6_ifaddr { int regen_count; bool tokenized; + bool managed; struct rcu_head rcu; struct in6_addr peer_addr; diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h index 437a6a4b125a..ed10d4ba8340 100644 --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -170,6 +170,7 @@ enum { DEVCONF_ACCEPT_RA_FROM_LOCAL, DEVCONF_USE_OPTIMISTIC, DEVCONF_ACCEPT_RA_MTU, + DEVCONF_FLUSH_ON_DOWN, DEVCONF_MAX }; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 7dcc065e2160..e0e82aad2116 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -202,6 +202,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { .accept_dad = 1, .suppress_frag_ndisc = 1, .accept_ra_mtu = 1, + .flush_addr_on_down = 1, }; static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { @@ -240,6 +241,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { .accept_dad = 1, .suppress_frag_ndisc = 1, .accept_ra_mtu = 1, + .flush_addr_on_down = 1, }; /* Check if a valid qdisc is available */ @@ -870,6 +872,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, ifa->prefered_lft = prefered_lft; ifa->cstamp = ifa->tstamp = jiffies; ifa->tokenized = false; + ifa->managed = false; ifa->rt = rt; @@ -2510,6 +2513,8 @@ static int inet6_addr_add(struct net *net, int ifindex, valid_lft, prefered_lft); if (!IS_ERR(ifp)) { + ifp->managed = true; + if (!(ifa_flags & IFA_F_NOPREFIXROUTE)) { addrconf_prefix_route(&ifp->addr, ifp->prefix_len, dev, expires, flags); @@ -3032,8 +3037,9 @@ static int addrconf_ifdown(struct net_device *dev, int how) { struct net *net = dev_net(dev); struct inet6_dev *idev; - struct inet6_ifaddr *ifa; + struct inet6_ifaddr *ifa, *tmp; int state, i; + struct list_head del_list; ASSERT_RTNL(); @@ -3067,9 +3073,12 @@ static int addrconf_ifdown(struct net_device *dev, int how) restart: hlist_for_each_entry_rcu(ifa, h, addr_lst) { if (ifa->idev == idev) { - hlist_del_init_rcu(&ifa->addr_lst); addrconf_del_dad_work(ifa); - goto restart; + if (how || idev->cnf.flush_addr_on_down || + !ifa->managed) { + hlist_del_init_rcu(&ifa->addr_lst); + goto restart; + } } } spin_unlock_bh(&addrconf_hash_lock); @@ -3103,14 +3112,35 @@ restart: write_lock_bh(&idev->lock); } - while (!list_empty(&idev->addr_list)) { - ifa = list_first_entry(&idev->addr_list, + INIT_LIST_HEAD(&del_list); + list_for_each_entry_safe(ifa, tmp, &idev->addr_list, if_list) { + /* + * on NETDEV_DOWN events do not flush managed (user configured) + * addresses unless configured to do so. If the address is not + * deleted reset flags and state such that DAD is re-done on a + * subsequent link up. + */ + if (!how && !idev->cnf.flush_addr_on_down && ifa->managed) { + if (!(ifa->flags & IFA_F_NODAD)) { + ifa->flags |= IFA_F_TENTATIVE; + ifa->state = INET6_IFADDR_STATE_DAD; + } + } else { + list_del(&ifa->if_list); + list_add(&ifa->if_list, &del_list); + } + } + + write_unlock_bh(&idev->lock); + + while (!list_empty(&del_list)) { + ifa = list_first_entry(&del_list, struct inet6_ifaddr, if_list); + addrconf_del_dad_work(ifa); list_del(&ifa->if_list); - write_unlock_bh(&idev->lock); spin_lock_bh(&ifa->state_lock); state = ifa->state; @@ -3122,12 +3152,8 @@ restart: inet6addr_notifier_call_chain(NETDEV_DOWN, ifa); } in6_ifa_put(ifa); - - write_lock_bh(&idev->lock); } - write_unlock_bh(&idev->lock); - /* Step 5: Discard anycast and multicast list */ if (how) { ipv6_ac_destroy_dev(idev); @@ -4383,6 +4409,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf, array[DEVCONF_SUPPRESS_FRAG_NDISC] = cnf->suppress_frag_ndisc; array[DEVCONF_ACCEPT_RA_FROM_LOCAL] = cnf->accept_ra_from_local; array[DEVCONF_ACCEPT_RA_MTU] = cnf->accept_ra_mtu; + array[DEVCONF_FLUSH_ON_DOWN] = cnf->flush_addr_on_down; } static inline size_t inet6_ifla6_size(void) @@ -5269,6 +5296,14 @@ static struct addrconf_sysctl_table .proc_handler = proc_dointvec, }, { + .procname = "flush_addr_on_down", + .data = &ipv6_devconf.flush_addr_on_down, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + + }, + { /* sentinel */ } }, -- 1.9.3