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* [PATCH net-next] ipv6: don't generate link-local addr in random or privacy mode
@ 2021-11-09  6:55 ` Rocco Yue
  0 siblings, 0 replies; 26+ messages in thread
From: Rocco Yue @ 2021-11-09  6:55 UTC (permalink / raw)
  To: David S . Miller, Jakub Kicinski, Jonathan Corbet,
	Hideaki YOSHIFUJI, David Ahern, Matthias Brugger
  Cc: netdev, linux-kernel, linux-arm-kernel, linux-mediatek,
	Rocco.Yue, chao.song, zhuoliang.zhang, yanjie.jiang, Rocco Yue

In the 3GPP TS 29.061, here is a description as follows:
"In order to avoid any conflict between the link-local address
of the MS and that of the GGSN, the Interface-Identifier used by
the MS to build its link-local address shall be assigned by the
GGSN. The GGSN ensures the uniqueness of this Interface-Identifier.
The MT shall then enforce the use of this Interface-Identifier by
the TE"

In other words, in the cellular network, GGSN determines whether
to reply a solicited RA message by identifying the bottom 64 bits
of the source address of the received RS message. Therefore,
cellular network device's ipv6 link-local address should be set
as the format of fe80::(GGSN assigned IID).

To meet the above spec requirement, this patch adds two new
addr_gen_mode:

1) IN6_ADDR_GEN_MODE_STABLE_PRIVACY_NO_LLA, this mode is suitable
for cellular networks that support RFC7217. In this mode, the
kernel doesn't generate a link-local address for the cellular
NIC, and generates an ipv6 stable privacy global address after
receiving the RA message.

2) IN6_ADDR_GEN_MODE_RANDOM_NO_LLA, in this mode, the kernel
doesn't generate a link-local address for the cellular NIC,
and will use the bottom 64 bits of the link-local address(same
as the IID assigned by GGSN) to form an ipv6 global address
after receiveing the RA message.

Signed-off-by: Rocco Yue <rocco.yue@mediatek.com>
---
 include/uapi/linux/if_link.h       |  2 ++
 net/ipv6/addrconf.c                | 22 ++++++++++++++++------
 tools/include/uapi/linux/if_link.h |  2 ++
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index eebd3894fe89..9c5695744c7d 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -428,6 +428,8 @@ enum in6_addr_gen_mode {
 	IN6_ADDR_GEN_MODE_NONE,
 	IN6_ADDR_GEN_MODE_STABLE_PRIVACY,
 	IN6_ADDR_GEN_MODE_RANDOM,
+	IN6_ADDR_GEN_MODE_STABLE_PRIVACY_NO_LLA,
+	IN6_ADDR_GEN_MODE_RANDOM_NO_LLA,
 };
 
 /* Bridge section */
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 3445f8017430..0045de10f4b5 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -392,7 +392,8 @@ static struct inet6_dev *ipv6_add_dev(struct net_device *dev)
 	timer_setup(&ndev->rs_timer, addrconf_rs_timer, 0);
 	memcpy(&ndev->cnf, dev_net(dev)->ipv6.devconf_dflt, sizeof(ndev->cnf));
 
-	if (ndev->cnf.stable_secret.initialized)
+	if (ndev->cnf.stable_secret.initialized &&
+	    ndev->cnf.addr_gen_mode != IN6_ADDR_GEN_MODE_STABLE_PRIVACY_NO_LLA)
 		ndev->cnf.addr_gen_mode = IN6_ADDR_GEN_MODE_STABLE_PRIVACY;
 
 	ndev->cnf.mtu6 = dev->mtu;
@@ -2578,7 +2579,8 @@ static void manage_tempaddrs(struct inet6_dev *idev,
 static bool is_addr_mode_generate_stable(struct inet6_dev *idev)
 {
 	return idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_STABLE_PRIVACY ||
-	       idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_RANDOM;
+	       idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_RANDOM ||
+	       idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_STABLE_PRIVACY_NO_LLA;
 }
 
 int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
@@ -3331,6 +3333,8 @@ static void addrconf_addr_gen(struct inet6_dev *idev, bool prefix_route)
 					      0, 0, GFP_KERNEL);
 		break;
 	case IN6_ADDR_GEN_MODE_NONE:
+	case IN6_ADDR_GEN_MODE_RANDOM_NO_LLA:
+	case IN6_ADDR_GEN_MODE_STABLE_PRIVACY_NO_LLA:
 	default:
 		/* will not add any link local address */
 		break;
@@ -5798,7 +5802,9 @@ static int check_addr_gen_mode(int mode)
 	if (mode != IN6_ADDR_GEN_MODE_EUI64 &&
 	    mode != IN6_ADDR_GEN_MODE_NONE &&
 	    mode != IN6_ADDR_GEN_MODE_STABLE_PRIVACY &&
-	    mode != IN6_ADDR_GEN_MODE_RANDOM)
+	    mode != IN6_ADDR_GEN_MODE_RANDOM &&
+	    mode != IN6_ADDR_GEN_MODE_STABLE_PRIVACY_NO_LLA &&
+	    mode != IN6_ADDR_GEN_MODE_RANDOM_NO_LLA)
 		return -EINVAL;
 	return 1;
 }
@@ -6428,15 +6434,19 @@ static int addrconf_sysctl_stable_secret(struct ctl_table *ctl, int write,
 		for_each_netdev(net, dev) {
 			struct inet6_dev *idev = __in6_dev_get(dev);
 
-			if (idev) {
+			if (idev && idev->cnf.addr_gen_mode !=
+			    IN6_ADDR_GEN_MODE_STABLE_PRIVACY_NO_LLA) {
 				idev->cnf.addr_gen_mode =
 					IN6_ADDR_GEN_MODE_STABLE_PRIVACY;
 			}
 		}
 	} else {
 		struct inet6_dev *idev = ctl->extra1;
-
-		idev->cnf.addr_gen_mode = IN6_ADDR_GEN_MODE_STABLE_PRIVACY;
+		if (idev->cnf.addr_gen_mode !=
+		    IN6_ADDR_GEN_MODE_STABLE_PRIVACY_NO_LLA) {
+			idev->cnf.addr_gen_mode =
+				IN6_ADDR_GEN_MODE_STABLE_PRIVACY;
+		}
 	}
 
 out:
diff --git a/tools/include/uapi/linux/if_link.h b/tools/include/uapi/linux/if_link.h
index b3610fdd1fee..fb69137aea89 100644
--- a/tools/include/uapi/linux/if_link.h
+++ b/tools/include/uapi/linux/if_link.h
@@ -241,6 +241,8 @@ enum in6_addr_gen_mode {
 	IN6_ADDR_GEN_MODE_NONE,
 	IN6_ADDR_GEN_MODE_STABLE_PRIVACY,
 	IN6_ADDR_GEN_MODE_RANDOM,
+	IN6_ADDR_GEN_MODE_STABLE_PRIVACY_NO_LLA,
+	IN6_ADDR_GEN_MODE_RANDOM_NO_LLA,
 };
 
 /* Bridge section */
-- 
2.18.0


^ permalink raw reply related	[flat|nested] 26+ messages in thread
* Re: [PATCH net-next v2] ipv6: don't generate link-local addr in random or privacy mode
@ 2021-11-17  5:09 Lorenzo Colitti
  2021-11-17  7:17   ` Rocco Yue
  0 siblings, 1 reply; 26+ messages in thread
From: Lorenzo Colitti @ 2021-11-17  5:09 UTC (permalink / raw)
  To: Rocco Yue
  Cc: David S . Miller, Jakub Kicinski, Jonathan Corbet,
	Hideaki YOSHIFUJI, David Ahern, Matthias Brugger, netdev,
	linux-kernel, linux-arm-kernel, linux-mediatek, rocco.yue,
	chao.song, yanjie.jiang, kuohong.wang, Zhuoliang.Zhang, maze,
	markzzzsmith

On Tue, Nov 16, 2021 at 3:15 PM Rocco Yue <rocco.yue@mediatek.com> wrote:
>
> In the 3GPP TS 29.061, here is a description as follows:
> "In order to avoid any conflict between the link-local address
> of the MS and that of the GGSN, the Interface-Identifier used by
> the MS to build its link-local address shall be assigned by the
> GGSN.
> [...]
> 1) IN6_ADDR_GEN_MODE_STABLE_PRIVACY_NO_LLA, this mode is suitable
> for cellular networks that support RFC7217. In this mode, the
> kernel doesn't generate a link-local address for the cellular
> NIC, and generates an ipv6 stable privacy global address after
> receiving the RA message.


It sounds like this would violate RFC 4291 section 2.1 which says "All
interfaces are required to have at least one Link-Local unicast
address. It is also not what 3GPP requires. 3GPP *does* require a
link-local address. It just requires that that the bottom 64 bits of
that link-local address be assigned by the network, not randomly.

Given that the kernel already supports tokenized interface addresses,
a better option here would be to add new addrgen modes where the
link-local address is formed from the interface token (idev->token),
and the other addresses are formed randomly or via RFC7217. These
modes could be called IN6_ADDR_GEN_MODE_RANDOM_LL_TOKEN and
IN6_ADDR_GEN_MODE_STABLE_PRIVACY_LL_TOKEN. When setting up the
interface, userspace could set disable_ipv6 to 1, then set the
interface token and the address generation mode via RTM_SETLINK, then
set disable_ipv6 to 0 to start autoconf. The kernel would then form
the link-local address via the token (which comes from the network),
and then set the global addresses either randomly or via RFC 7217.

^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH net-next] ipv6: don't generate link-local addr in random or privacy mode
@ 2021-11-17  5:59 ` Rocco Yue
  0 siblings, 0 replies; 26+ messages in thread
From: Rocco Yue @ 2021-11-17  5:59 UTC (permalink / raw)
  To: Jakub Kicinski, David Ahern
  Cc: David S . Miller, Jonathan Corbet, Hideaki YOSHIFUJI,
	Matthias Brugger, netdev, linux-kernel, linux-arm-kernel,
	linux-mediatek, Rocco.Yue, chao.song, yanjie.jiang, kuohong.wang,
	zhuoliang.zhang, lorenzo, maze, markzzzsmith, Rocco Yue

On Wed, 2021-11-17 at 11:34 +0800, Jakub Kicinski wrote:
> On Tue, 16 Nov 2021 13:21:12 -0700 David Ahern wrote:
>> Reviewed-by: David Ahern <dsahern@kernel.org>
>>
>> you should add tests under tools/testing/selftests/net.
>
> Please keep David's review tag and repost with a selftest.

Hi David and Jakub,

Thanks for your review. :-)

I heard about selftest for the first time, and I am thinking
about how to write a selftest for this patch, and I will
repost thses patches again when finished.

Thanks,

Rocco


^ permalink raw reply	[flat|nested] 26+ messages in thread

end of thread, other threads:[~2021-11-17 12:24 UTC | newest]

Thread overview: 26+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-11-09  6:55 [PATCH net-next] ipv6: don't generate link-local addr in random or privacy mode Rocco Yue
2021-11-09  6:55 ` Rocco Yue
2021-11-09  6:55 ` Rocco Yue
2021-11-13  8:46 ` Rocco Yue
2021-11-13  8:46   ` Rocco Yue
2021-11-13  8:46   ` Rocco Yue
2021-11-13 16:34   ` David Ahern
2021-11-13 16:34     ` David Ahern
2021-11-13 16:34     ` David Ahern
2021-11-16  2:21     ` Rocco Yue
2021-11-16  2:21       ` Rocco Yue
2021-11-16  2:21       ` Rocco Yue
2021-11-16  2:40       ` David Ahern
2021-11-16  2:40         ` David Ahern
2021-11-16  2:40         ` David Ahern
2021-11-17  5:09 [PATCH net-next v2] " Lorenzo Colitti
2021-11-17  7:17 ` [PATCH net-next] " Rocco Yue
2021-11-17  7:17   ` Rocco Yue
2021-11-17  7:17   ` Rocco Yue
2021-11-17  8:36   ` Lorenzo Colitti
2021-11-17  8:36     ` Lorenzo Colitti
2021-11-17  8:36     ` Lorenzo Colitti
2021-11-17  9:50     ` Maciej Żenczykowski
2021-11-17  9:50       ` Maciej Żenczykowski
2021-11-17  9:50       ` Maciej Żenczykowski
2021-11-17  5:59 Rocco Yue
2021-11-17  5:59 ` Rocco Yue

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