Commit 5f40ef77 authored by Hannes Frederic Sowa's avatar Hannes Frederic Sowa Committed by David S. Miller
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ipv6: do retries on stable privacy addresses 



If a DAD conflict is detected, we want to retry privacy stable address
generation up to idgen_retries (= 3) times with a delay of idgen_delay
(= 1 second). Add the logic to addrconf_dad_failure.

By design, we don't clean up dad failed permanent addresses.

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: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8e8e676d

include/net/if_inet6.h

+1 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ struct inet6_ifaddr { 


	__u32			flags;

	__u8			dad_probes;

	__u8			stable_privacy_retry;



	__u16			scope;

net/ipv6/addrconf.c

+54 −3
Original line number Diff line number Diff line
@@ -1710,6 +1710,7 @@ static int addrconf_dad_end(struct inet6_ifaddr *ifp) 


void addrconf_dad_failure(struct inet6_ifaddr *ifp)

{

	struct in6_addr addr;

	struct inet6_dev *idev = ifp->idev;



	if (addrconf_dad_end(ifp)) {
@@ -1720,9 +1721,59 @@ void addrconf_dad_failure(struct inet6_ifaddr *ifp) 
	net_info_ratelimited("%s: IPv6 duplicate address %pI6c detected!\n",

			     ifp->idev->dev->name, &ifp->addr);



	if (idev->cnf.accept_dad > 1 && !idev->cnf.disable_ipv6) {

		struct in6_addr addr;

	spin_lock_bh(&ifp->lock);



	if (ifp->flags & IFA_F_STABLE_PRIVACY) {

		int scope = ifp->scope;

		u32 flags = ifp->flags;

		struct in6_addr new_addr;

		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) {

			net_info_ratelimited("%s: privacy stable address generation failed because of DAD conflicts!\n",

					     ifp->idev->dev->name);

			goto errdad;

		}



		new_addr = ifp->addr;

		if (ipv6_generate_stable_address(&new_addr, retries,

						 idev))

			goto errdad;



		valid_lft = ifp->valid_lft;

		preferred_lft = ifp->prefered_lft;



		spin_unlock_bh(&ifp->lock);



		if (idev->cnf.max_addresses &&

		    ipv6_count_addresses(idev) >=

		    idev->cnf.max_addresses)

			goto lock_errdad;



		net_info_ratelimited("%s: generating new stable privacy address because of DAD conflict\n",

				     ifp->idev->dev->name);



		ifp2 = ipv6_add_addr(idev, &new_addr, NULL, pfxlen,

				     scope, flags, valid_lft,

				     preferred_lft);

		if (IS_ERR(ifp2))

			goto lock_errdad;



		spin_lock_bh(&ifp2->lock);

		ifp2->stable_privacy_retry = retries;

		ifp2->state = INET6_IFADDR_STATE_PREDAD;

		spin_unlock_bh(&ifp2->lock);



		addrconf_mod_dad_work(ifp2, idgen_delay);

		in6_ifa_put(ifp2);

lock_errdad:

		spin_lock_bh(&ifp->lock);

	} else if (idev->cnf.accept_dad > 1 && !idev->cnf.disable_ipv6) {

		addr.s6_addr32[0] = htonl(0xfe800000);

		addr.s6_addr32[1] = 0;
@@ -1736,7 +1787,7 @@ void addrconf_dad_failure(struct inet6_ifaddr *ifp) 
		}

	}



	spin_lock_bh(&ifp->lock);

errdad:

	/* transition from _POSTDAD to _ERRDAD */

	ifp->state = INET6_IFADDR_STATE_ERRDAD;

	spin_unlock_bh(&ifp->lock);

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