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ipv6: split duplicate address detection and router solicitation timer
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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@redhat.com>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: David Stevens <dlstevens@us.ibm.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Reviewed-by: Flavio Leitner <fbl@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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@strssndktn @davem330
strssndktn authored and davem330 committed Jun 25, 2013
1 parent 51151a1 commit b7b1bfc
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Showing 2 changed files with 97 additions and 75 deletions.
8 changes: 6 additions & 2 deletions include/net/if_inet6.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -50,15 +50,15 @@ struct inet6_ifaddr {

int state;

__u8 probes;
__u8 dad_probes;
__u8 flags;

__u16 scope;

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;
Expand Down Expand Up @@ -195,6 +195,10 @@ struct inet6_dev {
struct neigh_parms *nd_parms;
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;
};
Expand Down
164 changes: 91 additions & 73 deletions net/ipv6/addrconf.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand Down Expand Up @@ -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");
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);

Expand Down Expand Up @@ -1447,6 +1444,23 @@ int ipv6_dev_get_saddr(struct net *net, const struct net_device *dst_dev,
}
EXPORT_SYMBOL(ipv6_dev_get_saddr);

static int __ipv6_get_lladdr(struct inet6_dev *idev, struct in6_addr *addr,
unsigned char banned_flags)
{
struct inet6_ifaddr *ifp;
int err = -EADDRNOTAVAIL;

list_for_each_entry(ifp, &idev->addr_list, if_list) {
if (ifp->scope == IFA_LINK &&
!(ifp->flags & banned_flags)) {
*addr = ifp->addr;
err = 0;
break;
}
}
return err;
}

int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr,
unsigned char banned_flags)
{
Expand All @@ -1456,17 +1470,8 @@ int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr,
rcu_read_lock();
idev = __in6_dev_get(dev);
if (idev) {
struct inet6_ifaddr *ifp;

read_lock_bh(&idev->lock);
list_for_each_entry(ifp, &idev->addr_list, if_list) {
if (ifp->scope == IFA_LINK &&
!(ifp->flags & banned_flags)) {
*addr = ifp->addr;
err = 0;
break;
}
}
err = __ipv6_get_lladdr(idev, addr, banned_flags);
read_unlock_bh(&idev->lock);
}
rcu_read_unlock();
Expand Down Expand Up @@ -1580,7 +1585,7 @@ 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;
Expand Down Expand Up @@ -3036,7 +3041,7 @@ 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;
}
}
Expand All @@ -3045,6 +3050,8 @@ 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);
Expand Down Expand Up @@ -3074,7 +3081,7 @@ 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);

Expand Down Expand Up @@ -3116,10 +3123,10 @@ 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;

Expand All @@ -3130,18 +3137,19 @@ 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.
Expand All @@ -3150,8 +3158,8 @@ 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);
}

/*
Expand All @@ -3167,8 +3175,8 @@ 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)
Expand Down Expand Up @@ -3229,40 +3237,40 @@ 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);
Expand All @@ -3274,6 +3282,9 @@ static void addrconf_dad_timer(unsigned long data)
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.
Expand All @@ -3294,13 +3305,20 @@ 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);
}
}

Expand Down

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