From: Greg KH <gregkh@linuxfoundation.org>
To: Rocco Yue <rocco.yue@mediatek.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
David Ahern <dsahern@kernel.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
Felix Fietkau <nbd@nbd.name>, John Crispin <john@phrozen.org>,
Sean Wang <sean.wang@mediatek.com>,
Mark Lee <Mark-MC.Lee@mediatek.com>,
netdev@vger.kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org, bpf@vger.kernel.org,
wsd_upstream@mediatek.com, chao.song@mediatek.com,
kuohong.wang@mediatek.com
Subject: Re: [PATCH 1/4] net: if_arp: add ARPHRD_PUREIP type
Date: Thu, 24 Jun 2021 15:06:09 +0200 [thread overview]
Message-ID: <YNSDQbp/h/aadpmV@kroah.com> (raw)
In-Reply-To: <20210624122435.11887-1-rocco.yue@mediatek.com>
On Thu, Jun 24, 2021 at 08:24:35PM +0800, Rocco Yue wrote:
> On Thu, 2021-06-24 at 11:04 +0200, Greg KH wrote:
> On Thu, Jun 24, 2021 at 02:13:10PM +0800, Rocco Yue wrote:
> >> On Thu, 2021-06-24 at 07:29 +0200, Greg KH wrote:
> >>>
> >>> Thanks for the explaination, why is this hardware somehow "special" in
> >>> this way that this has never been needed before?
> >>>
> >>> thanks,
> >>>
> >>> greg k-h
> >>>
> >>
> >> Before kernel-4.18, RAWIP was the same as PUREIP, neither of them
> >> automatically generates an IPv6 link-local address, and the way to
> >> generate an IPv6 global address is the same.
> >>
> >> After kernel-4.18 (include 4.18 version), the behavior of RAWIP had
> >> changed due to the following patch:
> >> @@ static int ipv6_generate_eui64(u8 *eui, struct net_device *dev)
> >> + case ARPHRD_RAWIP:
> >> + return addrconf_ifid_rawip(eui, dev);
> >> }
> >> return -1;
> >> }
> >>
> >> the reason why the kernel doesn't need to generate the link-local
> >> address automatically is as follows:
> >>
> >> In the 3GPP 29.061, here is some description as follows:
> >> "in order to avoid any conflict between the link-local address of
> >> 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. Then 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 to the Router Solicitation message of UE by identifying the
> >> low 64bits of UE interface's ipv6 link-local address.
> >>
> >> When using a new kernel and RAWIP, kernel will generate an EUI64
> >> format ipv6 link-local address, and if the device uses this address
> >> to send RS, GGSN will not reply RA message.
> >>
> >> Therefore, in that background, we came up with PUREIP to make kernel
> >> doesn't generate a ipv6 link-local address in any address generate
> >> mode.
> >
> > Thanks for the better description. That should go into the changelog
> > text somewhere so that others know what is going on here with this new
> > option.
> >
>
> Does changelog mean adding these details to the commit message ?
Yes please.
> > And are these user-visable flags documented in a man page or something
> > else somewhere? If not, how does userspace know about them?
> >
>
> There are mappings of these device types value in the libc:
> "/bionic/libc/kernel/uapi/linux/if_arp.h".
> userspace can get it from here.
Yes, they will show up in a libc definition, but where is it documented
in text form what the flag does?
thanks,
greg k-h
next prev parent reply other threads:[~2021-06-24 13:06 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 11:34 [PATCH 1/4] net: if_arp: add ARPHRD_PUREIP type Rocco Yue
2021-06-23 11:34 ` [PATCH 2/4] net: ipv6: don't generate link local address on PUREIP device Rocco Yue
2021-06-23 11:34 ` [PATCH 3/4] net: dev_is_mac_header_xmit() return false for ARPHRD_PUREIP Rocco Yue
2021-06-23 11:34 ` [PATCH 4/4] drivers: net: mediatek: initial implementation of ccmni Rocco Yue
2021-06-23 17:25 ` Greg KH
2021-06-23 17:31 ` Greg KH
2021-06-24 11:53 ` [PATCH 1/4] net: if_arp: add ARPHRD_PUREIP type Rocco Yue
2021-06-24 12:23 ` Greg KH
2021-06-24 15:55 ` [PATCH 4/4] drivers: net: mediatek: initial implementation of ccmni Rocco Yue
2021-06-24 16:51 ` Greg KH
2021-06-28 7:18 ` Rocco Yue
2021-06-28 9:30 ` Greg KH
2021-06-23 17:19 ` [PATCH 1/4] net: if_arp: add ARPHRD_PUREIP type Greg KH
2021-06-24 3:33 ` Rocco Yue
2021-06-24 5:15 ` David Ahern
2021-06-24 5:31 ` Rocco Yue
2021-06-24 5:29 ` Greg KH
2021-06-24 6:13 ` Rocco Yue
2021-06-24 9:04 ` Greg KH
2021-06-24 12:24 ` Rocco Yue
2021-06-24 13:06 ` Greg KH [this message]
2021-06-25 6:01 ` Rocco Yue
2021-06-24 16:14 ` Dan Williams
2021-06-25 6:04 ` Rocco Yue
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