Re: [PATCH net-next v3] ipv6: add IFLA_INET6_RA_MTU to expose mtu value in the RA message
From: Rocco Yue <hidden>
Date: 2021-08-13 08:10:12
Also in:
linux-mediatek, lkml, netdev
On Wed, 2021-08-11 at 12:05 -0600, David Ahern wrote:
On 8/11/21 7:56 AM, David Ahern wrote:quoted
On 8/10/21 6:33 AM, Rocco Yue wrote:quoted
On Mon, 2021-08-09 at 16:43 -0600, David Ahern wrote:quoted
Since this MTU is getting reported via af_info infrastructure, rtmsg_ifinfo should be sufficient. From there use 'ip monitor' to make sure you are not generating multiple notifications; you may only need this on the error path.Hi David, To avoid generating multiple notifications, I added a separate ramtu notify function in this patch, and I added RTNLGRP_IPV6_IFINFO nl_mgrp to the ipmonitor.c to verify this patch was as expected. I look at the rtmsg_ifinfo code, it should be appropriate and I will use it and verify it. But there's one thing, I'm sorry I didn't fully understand the meaning of this sentence "you may only need this on the error path". Honestly, I'm not sure what the error patch refers to, do you mean "if (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu)" ?looks like nothing under: if (ndopts.nd_opts_mtu && in6_dev->cnf.accept_ra_mtu) { } is going to send a link notification so you can just replace inet6_iframtu_notify with rtmsg_ifinfo in your proposed change.Taking a deeper dive on the code, you do not need to call rtmsg_ifinfo. Instead, the existing: /* * Send a notify if RA changed managed/otherconf flags or timer settings */ if (send_ifinfo_notify) inet6_ifinfo_notify(RTM_NEWLINK, in6_dev); is called too early. For one the RA can change the MTU and that is done after this notify. I think if you moved this down to the out: out: /* * Send a notify if RA changed managed/otherconf flags or timer settings */ if (send_ifinfo_notify) inet6_ifinfo_notify(RTM_NEWLINK, in6_dev); and then set send_ifinfo_notify when the mtu is *changed* by the RA you should be good.
Hi David, Thanks for your suggestion, this looks like a better choice without adding a separate notification function, I will modify it and push the next iteration . Best Regards, Rocco _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel