On 2018/05/09 12:48, BRAND Arnaud wrote:
> Hi,
>
> I would like to report was looks like a bug in snmpd.
>
> When walking on the ifTable my client crashes when walking over 10G
> interfaces.
> Tcpdump shows that ifSpeed (1.3.6.1.2.1.2.2.1.5) is sending the value
> 10000000000 (10Gbps).
> But ifSpeed is of type GAUGE and maxes out at 2^32-1 (4Gbps-1).
>
> My MIB browser states :
> "An estimate of the interface's current bandwidth in bits
> per second. For interfaces which do not vary in bandwidth
> or for those where no accurate estimation can be made, this
> object should contain the nominal bandwidth. If the
> bandwidth of the interface is greater than the maximum value
> reportable by this object then this object should report its
> maximum value (4,294,967,295) and ifHighSpeed must be used
> to report the interace's speed. For a sub-layer which has
> no concept of bandwidth, this object should be zero."
>
> So I guess the case block at line 1111 in /usr.sbin/snmpd/mib.c should read :
> case 5:
> i = kif->if_baudrate >= 4294967295 ?
> 4294967295 : kif->if_baudrate ;
> ber = ber_add_integer(ber, i);
> ber_set_header(ber, BER_CLASS_APPLICATION,
> SNMP_T_GAUGE32);
> break;
> instead of
> case 5:
> ber = ber_add_integer(ber, kif->if_baudrate);
> ber_set_header(ber, BER_CLASS_APPLICATION,
> SNMP_T_GAUGE32);
> break;
>
> Is my assumption correct or have I missed something ?
>
> I'm gonna give it a try while a fix perhaps makes its way in the next release
> or patches.
>
> Have a nice day and thanks for your nice work in OpenBSD !
>
> Best regards
> Arnaud
I think that's the right thing to do, but an if() and using a macro
instead of writing 4294967295 out in full is easier on the eye.
Any OKs for this?
Index: mib.c
===================================================================
RCS file: /cvs/src/usr.sbin/snmpd/mib.c,v
retrieving revision 1.85
diff -u -p -r1.85 mib.c
--- mib.c 18 Dec 2017 05:51:53 -0000 1.85
+++ mib.c 9 May 2018 13:38:50 -0000
@@ -1109,7 +1109,11 @@ mib_iftable(struct oid *oid, struct ber_
ber = ber_add_integer(ber, kif->if_mtu);
break;
case 5:
- ber = ber_add_integer(ber, kif->if_baudrate);
+ if (kif->if_baudrate > UINT32_MAX) {
+ /* speed should be obtained from ifHighSpeed instead */
+ ber = ber_add_integer(ber, UINT32_MAX);
+ } else
+ ber = ber_add_integer(ber, kif->if_baudrate);
ber_set_header(ber, BER_CLASS_APPLICATION, SNMP_T_GAUGE32);
break;
case 6:
