Messages in this thread | | | From | Rocco Yue <> | Subject | Re: [PATCH 1/4] net: if_arp: add ARPHRD_PUREIP type | Date | Thu, 24 Jun 2021 11:33:53 +0800 |
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On Wed, 2021-06-23 at 19:19 +0200, Greg KH wrote: On Wed, Jun 23, 2021 at 07:34:49PM +0800, Rocco Yue wrote: >> This patch add the definition of ARPHRD_PUREIP which can for >> example be used by mobile ccmni device as device type. >> ARPHRD_PUREIP means that this device doesn't need kernel to >> generate ipv6 link-local address in any addr_gen_mode. >> >> Signed-off-by: Rocco Yue <rocco.yue@mediatek.com> >> --- >> include/uapi/linux/if_arp.h | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/include/uapi/linux/if_arp.h b/include/uapi/linux/if_arp.h >> index c3cc5a9e5eaf..4463c9e9e8b4 100644 >> --- a/include/uapi/linux/if_arp.h >> +++ b/include/uapi/linux/if_arp.h >> @@ -61,6 +61,7 @@ >> #define ARPHRD_DDCMP 517 /* Digital's DDCMP protocol */ >> #define ARPHRD_RAWHDLC 518 /* Raw HDLC */ >> #define ARPHRD_RAWIP 519 /* Raw IP */ >> +#define ARPHRD_PUREIP 520 /* Pure IP */ > > In looking at the patches, what differs "PUREIP" from "RAWIP"? It seems
Thanks for your review.
The difference between RAWIP and PUREIP is that they generate IPv6 link-local address and IPv6 global address in different ways.
RAWIP: ~~~~~~ In the ipv6_generate_eui64() function, using RAWIP will always return 0, which will cause the kernel to automatically generate an IPv6 link-local address in EUI64 format and an IPv6 global address in EUI64 format.
PUREIP: ~~~~~~~ After this patch set, when using PUREIP, kernel doesn't generate IPv6 link-local address regardless of which IN6_ADDR_GEN_MODE is used.
@@ static void addrconf_dev_config(struct net_device *dev) + if (dev->type == ARPHRD_PUREIP) + return;
And after recving RA message, kernel iterates over the link-local address that exists for the interface and uses the low 64bits of the link-local address to generate the IPv6 global address. The general process is as follows: ndisc_router_discovery() -> addrconf_prefix_rcv() -> ipv6_generate_eui64() -> ipv6_inherit_eui64()
> to be the same to me. If they are different, where is that documented? > > thanks, > > greg k-h
I tried to find corresponding documents about other device types, but I am sorry I didn't find it. If it is needed, I am willing to provide.
Thanks, Rocco
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