Re: git: 8338690a0a43 - main - ip_reass: provide sysctl MIB returning IP fragment TTL

> On 20. Aug 2022, at 22:41, Gleb Smirnoff <glebius@FreeBSD.org> wrote:
> 
> The branch main has been updated by glebius:
> 
> URL: https://cgit.FreeBSD.org/src/commit/?id=8338690a0a43c8b11a382e2160f8eedb9aeecf91
> 
> commit 8338690a0a43c8b11a382e2160f8eedb9aeecf91
> Author:     Gleb Smirnoff <glebius@FreeBSD.org>
> AuthorDate: 2022-08-20 20:33:39 +0000
> Commit:     Gleb Smirnoff <glebius@FreeBSD.org>
> CommitDate: 2022-08-20 20:39:12 +0000
> 
>    ip_reass: provide sysctl MIB returning IP fragment TTL
> 
>    For now it is read-only, but eventually the cycle that goes over
>    all fragments should be refactored and this MIB should also become
>    read/write.
> 
>    This MIB will allow SNMP daemons to implement MIB-II ipReasmTimeout MIB
>    straightfoward.  Right now net-snmp compilation is broken by 1922eb3e9c2.
>    The base system bsnmpd is not broken just because it ignored PR_SLOWTIMO,
>    and thus always returned incorrectly doubled value for ipReasmTimeout.
> ---
> sys/netinet/ip_reass.c | 4 ++++
> 1 file changed, 4 insertions(+)
> 
> diff --git a/sys/netinet/ip_reass.c b/sys/netinet/ip_reass.c
> index 0420091e0a2a..e581e2e622c7 100644
> --- a/sys/netinet/ip_reass.c
> +++ b/sys/netinet/ip_reass.c
> @@ -167,6 +167,10 @@ SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragbucketsize,
>     sysctl_maxfragbucketsize, "I",
>     "Maximum number of IPv4 fragment reassembly queue entries per bucket");
> 
> +static u_int ipfragttl = IPFRAGTTL / 2;
> +SYSCTL_UINT(_net_inet_ip, OID_AUTO, fragttl, CTLFLAG_RD, &ipfragttl,
> +    IPFRAGTTL / 2, "IP fragment life time on reassembly queue");
What unit is used? seconds? milliseconds? You might want to state that.
What us the semantic of IPFRAGTTL? What is the unit of that constant?

Best regards
Michael
> +
> /*
>  * Take incoming datagram fragment and try to reassemble it into
>  * whole datagram.  If the argument is the first fragment or one