[PATCH 4.15 11/23] net: ipv6: send unsolicited NA after DAD

From: Greg Kroah-Hartman
Date: Fri Feb 09 2018 - 08:46:21 EST


4.15-stable review patch. If anyone has any objections, please let me know.

------------------

From: David Ahern <dsahern@xxxxxxxxx>


[ Upstream commit c76fe2d98c726224a975a0d0198c3fb50406d325 ]

Unsolicited IPv6 neighbor advertisements should be sent after DAD
completes. Update ndisc_send_unsol_na to skip tentative, non-optimistic
addresses and have those sent by addrconf_dad_completed after DAD.

Fixes: 4a6e3c5def13c ("net: ipv6: send unsolicited NA on admin up")
Reported-by: Vivek Venkatraman <vivek@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David Ahern <dsahern@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/addrconf.c | 30 ++++++++++++++++++++++++++----
net/ipv6/ndisc.c | 5 +++++
2 files changed, 31 insertions(+), 4 deletions(-)

--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -186,7 +186,8 @@ static struct rt6_info *addrconf_get_pre

static void addrconf_dad_start(struct inet6_ifaddr *ifp);
static void addrconf_dad_work(struct work_struct *w);
-static void addrconf_dad_completed(struct inet6_ifaddr *ifp, bool bump_id);
+static void addrconf_dad_completed(struct inet6_ifaddr *ifp, bool bump_id,
+ bool send_na);
static void addrconf_dad_run(struct inet6_dev *idev);
static void addrconf_rs_timer(struct timer_list *t);
static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifa);
@@ -3833,12 +3834,17 @@ static void addrconf_dad_begin(struct in
idev->cnf.accept_dad < 1) ||
!(ifp->flags&IFA_F_TENTATIVE) ||
ifp->flags & IFA_F_NODAD) {
+ bool send_na = false;
+
+ if (ifp->flags & IFA_F_TENTATIVE &&
+ !(ifp->flags & IFA_F_OPTIMISTIC))
+ send_na = true;
bump_id = ifp->flags & IFA_F_TENTATIVE;
ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC|IFA_F_DADFAILED);
spin_unlock(&ifp->lock);
read_unlock_bh(&idev->lock);

- addrconf_dad_completed(ifp, bump_id);
+ addrconf_dad_completed(ifp, bump_id, send_na);
return;
}

@@ -3967,16 +3973,21 @@ static void addrconf_dad_work(struct wor
}

if (ifp->dad_probes == 0) {
+ bool send_na = false;
+
/*
* DAD was successful
*/

+ if (ifp->flags & IFA_F_TENTATIVE &&
+ !(ifp->flags & IFA_F_OPTIMISTIC))
+ send_na = true;
bump_id = ifp->flags & IFA_F_TENTATIVE;
ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC|IFA_F_DADFAILED);
spin_unlock(&ifp->lock);
write_unlock_bh(&idev->lock);

- addrconf_dad_completed(ifp, bump_id);
+ addrconf_dad_completed(ifp, bump_id, send_na);

goto out;
}
@@ -4014,7 +4025,8 @@ static bool ipv6_lonely_lladdr(struct in
return true;
}

-static void addrconf_dad_completed(struct inet6_ifaddr *ifp, bool bump_id)
+static void addrconf_dad_completed(struct inet6_ifaddr *ifp, bool bump_id,
+ bool send_na)
{
struct net_device *dev = ifp->idev->dev;
struct in6_addr lladdr;
@@ -4046,6 +4058,16 @@ static void addrconf_dad_completed(struc
if (send_mld)
ipv6_mc_dad_complete(ifp->idev);

+ /* send unsolicited NA if enabled */
+ if (send_na &&
+ (ifp->idev->cnf.ndisc_notify ||
+ dev_net(dev)->ipv6.devconf_all->ndisc_notify)) {
+ ndisc_send_na(dev, &in6addr_linklocal_allnodes, &ifp->addr,
+ /*router=*/ !!ifp->idev->cnf.forwarding,
+ /*solicited=*/ false, /*override=*/ true,
+ /*inc_opt=*/ true);
+ }
+
if (send_rs) {
/*
* If a host as already performed a random delay
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -566,6 +566,11 @@ static void ndisc_send_unsol_na(struct n

read_lock_bh(&idev->lock);
list_for_each_entry(ifa, &idev->addr_list, if_list) {
+ /* skip tentative addresses until dad completes */
+ if (ifa->flags & IFA_F_TENTATIVE &&
+ !(ifa->flags & IFA_F_OPTIMISTIC))
+ continue;
+
ndisc_send_na(dev, &in6addr_linklocal_allnodes, &ifa->addr,
/*router=*/ !!idev->cnf.forwarding,
/*solicited=*/ false, /*override=*/ true,