[PATCH 3.10 220/319] ipv6: split duplicate address detection and router solicitation timer

From: Willy Tarreau
Date: Sun Feb 05 2017 - 15:10:08 EST

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From: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>

commit b7b1bfce0bb68bd8f6e62a28295922785cc63781 upstream.

This patch splits the timers for duplicate address detection and router
solicitations apart. The router solicitations timer goes into inet6_dev
and the dad timer stays in inet6_ifaddr.

The reason behind this patch is to reduce the number of unneeded router
solicitations send out by the host if additional link-local addresses
are created. Currently we send out RS for every link-local address on
an interface.

If the RS timer fires we pick a source address with ipv6_get_lladdr. This
change could hurt people adding additional link-local addresses and
specifying these addresses in the radvd clients section because we
no longer guarantee that we use every ll address as source address in
router solicitations.

Cc: Flavio Leitner <fleitner@xxxxxxxxxx>
Cc: Hideaki YOSHIFUJI <yoshfuji@xxxxxxxxxxxxxx>
Cc: David Stevens <dlstevens@xxxxxxxxxx>
Signed-off-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Flavio Leitner <fbl@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
[Mike Manning <mmanning@xxxxxxxxxxx>: resolved conflicts with 36bddb]
Signed-off-by: Mike Manning <mmanning@xxxxxxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
include/net/if_inet6.h | 8 ++-
net/ipv6/addrconf.c | 136 ++++++++++++++++++++++++++-----------------------
2 files changed, 79 insertions(+), 65 deletions(-)

diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index 100fb8c..3b558c6 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -50,7 +50,7 @@ struct inet6_ifaddr {

int state;

- __u8 probes;
+ __u8 dad_probes;
__u8 flags;

__u16 scope;
@@ -58,7 +58,7 @@ struct inet6_ifaddr {
unsigned long cstamp; /* created timestamp */
unsigned long tstamp; /* updated timestamp */

- struct timer_list timer;
+ struct timer_list dad_timer;

struct inet6_dev *idev;
struct rt6_info *rt;
@@ -195,6 +195,10 @@ struct inet6_dev {
struct inet6_dev *next;
struct ipv6_devconf cnf;
struct ipv6_devstat stats;
+
+ struct timer_list rs_timer;
+ __u8 rs_probes;
+
unsigned long tstamp; /* ipv6InterfaceTable update timestamp */
struct rcu_head rcu;
};
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index d0912ac..4ff6a9c 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -253,37 +253,32 @@ static inline bool addrconf_qdisc_ok(const struct net_device *dev)
return !qdisc_tx_is_noop(dev);
}

-static void addrconf_del_timer(struct inet6_ifaddr *ifp)
+static void addrconf_del_rs_timer(struct inet6_dev *idev)
{
- if (del_timer(&ifp->timer))
+ if (del_timer(&idev->rs_timer))
+ __in6_dev_put(idev);
+}
+
+static void addrconf_del_dad_timer(struct inet6_ifaddr *ifp)
+{
+ if (del_timer(&ifp->dad_timer))
__in6_ifa_put(ifp);
}

-enum addrconf_timer_t {
- AC_NONE,
- AC_DAD,
- AC_RS,
-};
+static void addrconf_mod_rs_timer(struct inet6_dev *idev,
+ unsigned long when)
+{
+ if (!timer_pending(&idev->rs_timer))
+ in6_dev_hold(idev);
+ mod_timer(&idev->rs_timer, jiffies + when);
+}

-static void addrconf_mod_timer(struct inet6_ifaddr *ifp,
- enum addrconf_timer_t what,
- unsigned long when)
+static void addrconf_mod_dad_timer(struct inet6_ifaddr *ifp,
+ unsigned long when)
{
- if (!del_timer(&ifp->timer))
+ if (!timer_pending(&ifp->dad_timer))
in6_ifa_hold(ifp);
-
- switch (what) {
- case AC_DAD:
- ifp->timer.function = addrconf_dad_timer;
- break;
- case AC_RS:
- ifp->timer.function = addrconf_rs_timer;
- break;
- default:
- break;
- }
- ifp->timer.expires = jiffies + when;
- add_timer(&ifp->timer);
+ mod_timer(&ifp->dad_timer, jiffies + when);
}

static int snmp6_alloc_dev(struct inet6_dev *idev)
@@ -326,6 +321,7 @@ void in6_dev_finish_destroy(struct inet6_dev *idev)

WARN_ON(!list_empty(&idev->addr_list));
WARN_ON(idev->mc_list != NULL);
+ WARN_ON(timer_pending(&idev->rs_timer));

#ifdef NET_REFCNT_DEBUG
pr_debug("%s: %s\n", __func__, dev ? dev->name : "NIL");
@@ -357,7 +353,8 @@ static struct inet6_dev *ipv6_add_dev(struct net_device *dev)
rwlock_init(&ndev->lock);
ndev->dev = dev;
INIT_LIST_HEAD(&ndev->addr_list);
-
+ setup_timer(&ndev->rs_timer, addrconf_rs_timer,
+ (unsigned long)ndev);
memcpy(&ndev->cnf, dev_net(dev)->ipv6.devconf_dflt, sizeof(ndev->cnf));
ndev->cnf.mtu6 = dev->mtu;
ndev->cnf.sysctl = NULL;
@@ -776,7 +773,7 @@ void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp)

in6_dev_put(ifp->idev);

- if (del_timer(&ifp->timer))
+ if (del_timer(&ifp->dad_timer))
pr_notice("Timer is still running, when freeing ifa=%p\n", ifp);

if (ifp->state != INET6_IFADDR_STATE_DEAD) {
@@ -869,9 +866,9 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, int pfxlen,

spin_lock_init(&ifa->lock);
spin_lock_init(&ifa->state_lock);
- init_timer(&ifa->timer);
+ setup_timer(&ifa->dad_timer, addrconf_dad_timer,
+ (unsigned long)ifa);
INIT_HLIST_NODE(&ifa->addr_lst);
- ifa->timer.data = (unsigned long) ifa;
ifa->scope = scope;
ifa->prefix_len = pfxlen;
ifa->flags = flags | IFA_F_TENTATIVE;
@@ -994,7 +991,7 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)
}
write_unlock_bh(&idev->lock);

- addrconf_del_timer(ifp);
+ addrconf_del_dad_timer(ifp);

ipv6_ifa_notify(RTM_DELADDR, ifp);

@@ -1617,7 +1614,7 @@ static void addrconf_dad_stop(struct inet6_ifaddr *ifp, int dad_failed)
{
if (ifp->flags&IFA_F_PERMANENT) {
spin_lock_bh(&ifp->lock);
- addrconf_del_timer(ifp);
+ addrconf_del_dad_timer(ifp);
ifp->flags |= IFA_F_TENTATIVE;
if (dad_failed)
ifp->flags |= IFA_F_DADFAILED;
@@ -3085,7 +3082,7 @@ static int addrconf_ifdown(struct net_device *dev, int how)
hlist_for_each_entry_rcu(ifa, h, addr_lst) {
if (ifa->idev == idev) {
hlist_del_init_rcu(&ifa->addr_lst);
- addrconf_del_timer(ifa);
+ addrconf_del_dad_timer(ifa);
goto restart;
}
}
@@ -3094,6 +3091,8 @@ static int addrconf_ifdown(struct net_device *dev, int how)

write_lock_bh(&idev->lock);

+ addrconf_del_rs_timer(idev);
+
/* Step 2: clear flags for stateless addrconf */
if (!how)
idev->if_flags &= ~(IF_RS_SENT|IF_RA_RCVD|IF_READY);
@@ -3123,7 +3122,7 @@ static int addrconf_ifdown(struct net_device *dev, int how)
while (!list_empty(&idev->addr_list)) {
ifa = list_first_entry(&idev->addr_list,
struct inet6_ifaddr, if_list);
- addrconf_del_timer(ifa);
+ addrconf_del_dad_timer(ifa);

list_del(&ifa->if_list);

@@ -3165,10 +3164,10 @@ static int addrconf_ifdown(struct net_device *dev, int how)

static void addrconf_rs_timer(unsigned long data)
{
- struct inet6_ifaddr *ifp = (struct inet6_ifaddr *) data;
- struct inet6_dev *idev = ifp->idev;
+ struct inet6_dev *idev = (struct inet6_dev *)data;
+ struct in6_addr lladdr;

- read_lock(&idev->lock);
+ write_lock(&idev->lock);
if (idev->dead || !(idev->if_flags & IF_READY))
goto out;

@@ -3179,18 +3178,19 @@ static void addrconf_rs_timer(unsigned long data)
if (idev->if_flags & IF_RA_RCVD)
goto out;

- spin_lock(&ifp->lock);
- if (ifp->probes++ < idev->cnf.rtr_solicits) {
- /* The wait after the last probe can be shorter */
- addrconf_mod_timer(ifp, AC_RS,
- (ifp->probes == idev->cnf.rtr_solicits) ?
- idev->cnf.rtr_solicit_delay :
- idev->cnf.rtr_solicit_interval);
- spin_unlock(&ifp->lock);
+ if (idev->rs_probes++ < idev->cnf.rtr_solicits) {
+ if (!__ipv6_get_lladdr(idev, &lladdr, IFA_F_TENTATIVE))
+ ndisc_send_rs(idev->dev, &lladdr,
+ &in6addr_linklocal_allrouters);
+ else
+ goto out;

- ndisc_send_rs(idev->dev, &ifp->addr, &in6addr_linklocal_allrouters);
+ /* The wait after the last probe can be shorter */
+ addrconf_mod_rs_timer(idev, (idev->rs_probes ==
+ idev->cnf.rtr_solicits) ?
+ idev->cnf.rtr_solicit_delay :
+ idev->cnf.rtr_solicit_interval);
} else {
- spin_unlock(&ifp->lock);
/*
* Note: we do not support deprecated "all on-link"
* assumption any longer.
@@ -3199,8 +3199,8 @@ static void addrconf_rs_timer(unsigned long data)
}

out:
- read_unlock(&idev->lock);
- in6_ifa_put(ifp);
+ write_unlock(&idev->lock);
+ in6_dev_put(idev);
}

/*
@@ -3216,8 +3216,8 @@ static void addrconf_dad_kick(struct inet6_ifaddr *ifp)
else
rand_num = net_random() % (idev->cnf.rtr_solicit_delay ? : 1);

- ifp->probes = idev->cnf.dad_transmits;
- addrconf_mod_timer(ifp, AC_DAD, rand_num);
+ ifp->dad_probes = idev->cnf.dad_transmits;
+ addrconf_mod_dad_timer(ifp, rand_num);
}

static void addrconf_dad_start(struct inet6_ifaddr *ifp)
@@ -3278,40 +3278,40 @@ static void addrconf_dad_timer(unsigned long data)
struct inet6_dev *idev = ifp->idev;
struct in6_addr mcaddr;

- if (!ifp->probes && addrconf_dad_end(ifp))
+ if (!ifp->dad_probes && addrconf_dad_end(ifp))
goto out;

- read_lock(&idev->lock);
+ write_lock(&idev->lock);
if (idev->dead || !(idev->if_flags & IF_READY)) {
- read_unlock(&idev->lock);
+ write_unlock(&idev->lock);
goto out;
}

spin_lock(&ifp->lock);
if (ifp->state == INET6_IFADDR_STATE_DEAD) {
spin_unlock(&ifp->lock);
- read_unlock(&idev->lock);
+ write_unlock(&idev->lock);
goto out;
}

- if (ifp->probes == 0) {
+ if (ifp->dad_probes == 0) {
/*
* DAD was successful
*/

ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC|IFA_F_DADFAILED);
spin_unlock(&ifp->lock);
- read_unlock(&idev->lock);
+ write_unlock(&idev->lock);

addrconf_dad_completed(ifp);

goto out;
}

- ifp->probes--;
- addrconf_mod_timer(ifp, AC_DAD, ifp->idev->nd_parms->retrans_time);
+ ifp->dad_probes--;
+ addrconf_mod_dad_timer(ifp, ifp->idev->nd_parms->retrans_time);
spin_unlock(&ifp->lock);
- read_unlock(&idev->lock);
+ write_unlock(&idev->lock);

/* send a neighbour solicitation for our addr */
addrconf_addr_solict_mult(&ifp->addr, &mcaddr);
@@ -3323,6 +3323,9 @@ out:
static void addrconf_dad_completed(struct inet6_ifaddr *ifp)
{
struct net_device *dev = ifp->idev->dev;
+ struct in6_addr lladdr;
+
+ addrconf_del_dad_timer(ifp);

/*
* Configure the address for reception. Now it is valid.
@@ -3343,13 +3346,20 @@ static void addrconf_dad_completed(struct inet6_ifaddr *ifp)
* [...] as part of DAD [...] there is no need
* to delay again before sending the first RS
*/
- ndisc_send_rs(ifp->idev->dev, &ifp->addr, &in6addr_linklocal_allrouters);
+ if (!ipv6_get_lladdr(dev, &lladdr, IFA_F_TENTATIVE))
+ ndisc_send_rs(dev, &lladdr,
+ &in6addr_linklocal_allrouters);
+ else
+ return;

- spin_lock_bh(&ifp->lock);
- ifp->probes = 1;
+ write_lock_bh(&ifp->idev->lock);
+ spin_lock(&ifp->lock);
+ ifp->idev->rs_probes = 1;
ifp->idev->if_flags |= IF_RS_SENT;
- addrconf_mod_timer(ifp, AC_RS, ifp->idev->cnf.rtr_solicit_interval);
- spin_unlock_bh(&ifp->lock);
+ addrconf_mod_rs_timer(ifp->idev,
+ ifp->idev->cnf.rtr_solicit_interval);
+ spin_unlock(&ifp->lock);
+ write_unlock_bh(&ifp->idev->lock);
}
}

--
2.8.0.rc2.1.gbe9624a

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