Re: [PATCH] rtnetlink.7: Document struct ifa_cacheinfo

[Kuniyuki Iwashima <kuniyu@amazon.com>]

From: Alex Henrie <alexhenrie24@gmail.com>
Date: Mon,  4 Nov 2024 21:14:20 -0700
> struct ifa_cacheinfo contains the address's creation time, update time,
> preferred lifetime, and valid lifetime. See
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/if_addr.h?h=v6.11#n60
> 
> Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
> ---
>  man/man7/rtnetlink.7 | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/man/man7/rtnetlink.7 b/man/man7/rtnetlink.7
> index 86ed459bb..b05654315 100644
> --- a/man/man7/rtnetlink.7
> +++ b/man/man7/rtnetlink.7
> @@ -176,7 +176,15 @@ IFA_BROADCAST:raw protocol address:broadcast address
>  IFA_ANYCAST:raw protocol address:anycast address
>  IFA_CACHEINFO:struct ifa_cacheinfo:Address information
>  .TE
> -.\" FIXME Document struct ifa_cacheinfo
> +.IP
> +.EX
> +struct ifa_cacheinfo {
> +    __u32 ifa_prefered; /* Preferred lifetime in seconds, -1 = forever */
> +    __u32 ifa_valid;    /* Valid lifetime in seconds, -1 = forever */

-1 should be rather 0xFFFFFFFF (INFINITY_LIFE_TIME) as it's unsigned.

Also, it would be nice to mention that ifa_prefered must be less than
or equal to ifa_valid (ifa_prefered <= ifa_valid) and 0 is invalid for
ifa_valid.

  0 <= ifa_prefered <= ifa_valid
  0 < ifa_valid <= 0xFFFFFFFF


> +    __u32 cstamp;       /* Creation timestamp in hundredths of seconds */
> +    __u32 tstamp;       /* Update timestamp in hundredths of seconds */
> +};

Maybe the explanation can follow the struct here as sentences.


> +.EE
>  .TP
>  .B RTM_NEWROUTE
>  .TQ
> -- 
> 2.47.0