* Problems with getifaddrs
@ 2021-07-26 15:15 Ken Brown
2021-07-26 23:04 ` Andrey Repin
0 siblings, 1 reply; 3+ messages in thread
From: Ken Brown @ 2021-07-26 15:15 UTC (permalink / raw)
To: cygwin
While investigating emacs test failures, I found two problems with the
interfaces returned by getifaddrs(3):
1. For an IPv6 interface, the netmask address family is always 0 instead of
AF_INET6.
2. For a disconnected interface, the IPv4 address and netmask are sometimes 0.
I will be sending patches to fix these problems later today, but I wanted to
report them here for reference.
I don't know enough about this to be sure that problem 2 is really a Cygwin bug.
Are there cases where a 0 IP address is appropriate? Or should it be up to
the caller of getifaddrs to handle that case?
Ken
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Problems with getifaddrs
2021-07-26 15:15 Problems with getifaddrs Ken Brown
@ 2021-07-26 23:04 ` Andrey Repin
2021-07-29 14:43 ` Ken Brown
0 siblings, 1 reply; 3+ messages in thread
From: Andrey Repin @ 2021-07-26 23:04 UTC (permalink / raw)
To: Ken Brown, cygwin
Greetings, Ken Brown!
> While investigating emacs test failures, I found two problems with the
> interfaces returned by getifaddrs(3):
> 1. For an IPv6 interface, the netmask address family is always 0 instead of
> AF_INET6.
> 2. For a disconnected interface, the IPv4 address and netmask are sometimes 0.
For a disconnected interface this could be true as
Configuration for interface "TAP12"
DHCP enabled: Yes
IP Address: 172.16.40.6
Subnet Prefix: 172.16.40.0/24 (mask 255.255.255.0)
InterfaceMetric: 25
Configuration for interface "TAP55"
DHCP enabled: Yes
InterfaceMetric: 25
Configuration for interface "TAP63"
DHCP enabled: No
IP Address: 172.18.104.18
Subnet Prefix: 172.18.104.0/22 (mask 255.255.252.0)
InterfaceMetric: 25
There's actually no IP address assigned to TAP55, which could be reported as 0/0.
Can you please cross-check with
netsh interface ipv4 show addr
> I will be sending patches to fix these problems later today, but I wanted to
> report them here for reference.
> I don't know enough about this to be sure that problem 2 is really a Cygwin bug.
> Are there cases where a 0 IP address is appropriate? Or should it be up to
> the caller of getifaddrs to handle that case?
--
With best regards,
Andrey Repin
Tuesday, July 27, 2021 1:57:57
Sorry for my terrible english...
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Problems with getifaddrs
2021-07-26 23:04 ` Andrey Repin
@ 2021-07-29 14:43 ` Ken Brown
0 siblings, 0 replies; 3+ messages in thread
From: Ken Brown @ 2021-07-29 14:43 UTC (permalink / raw)
To: cygwin
On 7/26/2021 7:04 PM, Andrey Repin wrote:
> There's actually no IP address assigned to TAP55, which could be reported as 0/0.
Follow-up for the sake of the archives: The question I raised is whether
getifaddrs *should* report an IP address of 0/0 in this case. After checking
what happens on Linux, Corinna agreed that it should not do this, and we've now
changed it:
https://cygwin.com/git/?p=newlib-cygwin.git;a=commit;h=b88d686a68d7bf2ff22d857a28d37fe4fdbafdf2
Ken
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-07-26 15:15 Problems with getifaddrs Ken Brown
2021-07-26 23:04 ` Andrey Repin
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