ipv6: introduce idgen_delay and idgen_retries knobs

This is specified by RFC 7217.

Cc: Erik Kline <ek@google.com>
Cc: Fernando Gont <fgont@si6networks.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Cc: YOSHIFUJI Hideaki/吉藤英明 <hideaki.yoshifuji@miraclelinux.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 22 insertions, 7 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 9b51fdb42ba9..d2d238334a11 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1712,6 +1712,7 @@ void addrconf_dad_failure(struct inet6_ifaddr *ifp)
 {
         struct in6_addr addr;
         struct inet6_dev *idev = ifp->idev;
+        struct net *net = dev_net(ifp->idev->dev);
 
         if (addrconf_dad_end(ifp)) {
                 in6_ifa_put(ifp);
@@ -1730,11 +1731,9 @@ void addrconf_dad_failure(struct inet6_ifaddr *ifp)
                 struct inet6_ifaddr *ifp2;
                 u32 valid_lft, preferred_lft;
                 int pfxlen = ifp->prefix_len;
-                const unsigned int idgen_retries = 3;
-                const unsigned int idgen_delay = 1 * HZ;
                 int retries = ifp->stable_privacy_retry + 1;
 
-                if (retries > idgen_retries) {
+                if (retries > net->ipv6.sysctl.idgen_retries) {
                         net_info_ratelimited("%s: privacy stable address generation failed because of DAD conflicts!\n",
                                              ifp->idev->dev->name);
                         goto errdad;
@@ -1769,7 +1768,7 @@ void addrconf_dad_failure(struct inet6_ifaddr *ifp)
                 ifp2->state = INET6_IFADDR_STATE_PREDAD;
                 spin_unlock_bh(&ifp2->lock);
 
-                addrconf_mod_dad_work(ifp2, idgen_delay);
+                addrconf_mod_dad_work(ifp2, net->ipv6.sysctl.idgen_delay);
                 in6_ifa_put(ifp2);
 lock_errdad:
                 spin_lock_bh(&ifp->lock);
@@ -2899,8 +2898,6 @@ static int ipv6_generate_stable_address(struct in6_addr *address,
                                         u8 dad_count,
                                         const struct inet6_dev *idev)
 {
-        static const int idgen_retries = 3;
-
         static DEFINE_SPINLOCK(lock);
         static __u32 digest[SHA_DIGEST_WORDS];
         static __u32 workspace[SHA_WORKSPACE_WORDS];
@@ -2950,7 +2947,7 @@ retry:
 
         if (ipv6_reserved_interfaceid(temp)) {
                 dad_count++;
-                if (dad_count > idgen_retries)
+                if (dad_count > dev_net(idev->dev)->ipv6.sysctl.idgen_retries)
                         return -1;
                 goto retry;
         }
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 6bafcc2c79e3..d8dcc526339e 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -766,6 +766,8 @@ static int __net_init inet6_net_init(struct net *net)
         net->ipv6.sysctl.icmpv6_time = 1*HZ;
         net->ipv6.sysctl.flowlabel_consistency = 1;
         net->ipv6.sysctl.auto_flowlabels = 0;
+        net->ipv6.sysctl.idgen_retries = 3;
+        net->ipv6.sysctl.idgen_delay = 1 * HZ;
         atomic_set(&net->ipv6.fib6_sernum, 1);
 
         err = ipv6_init_mibs(net);
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index c5c10fafcfe2..30f5a4ad04eb 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -54,6 +54,20 @@ static struct ctl_table ipv6_table_template[] = {
                 .mode           = 0644,
                 .proc_handler   = proc_dointvec
         },
+        {
+                .procname       = "idgen_retries",
+                .data           = &init_net.ipv6.sysctl.idgen_retries,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = proc_dointvec,
+        },
+        {
+                .procname       = "idgen_delay",
+                .data           = &init_net.ipv6.sysctl.idgen_delay,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = proc_dointvec_jiffies,
+        },
         { }
 };
 
@@ -93,6 +107,8 @@ static int __net_init ipv6_sysctl_net_init(struct net *net)
         ipv6_table[2].data = &net->ipv6.sysctl.flowlabel_consistency;
         ipv6_table[3].data = &net->ipv6.sysctl.auto_flowlabels;
         ipv6_table[4].data = &net->ipv6.sysctl.fwmark_reflect;
+        ipv6_table[5].data = &net->ipv6.sysctl.idgen_retries;
+        ipv6_table[6].data = &net->ipv6.sysctl.idgen_delay;
 
         ipv6_route_table = ipv6_route_sysctl_init(net);
         if (!ipv6_route_table)