[Openswan Users] kernel 2.4.26 + Openswan 2.1.4 + net-snmp-5.1 = Kernel Oops

[Martin Bene]

Martin Bene wrote:

Looked at this some more; Not restricted to Openswan 2.1.4, also happens 
with 2.2.0dr2 and with current strongswan release.

Problem occurs when snmpd tries to figure out transmission speed for the 
interfaces:

<agent/mibgroup/mibII/interfaces.c>
...
if (ioctl(fd, 0x8947, &ifr) >= 0) {
     new_ioctl_nums = 1;
} else if (ioctl(fd, SIOCDEVPRIVATE, &ifr) >= 0) {
     new_ioctl_nums = 0;
...

So, it first tries SIOCGMIIREG ioctl; if that doesn't work, it falls 
back to SIOCDEVPRIVATE which seems to have been previously used for this 
purpose.

ipsec however uses SIOCDEVPRIVATE completely differently:

/* attach a virtual ipsec? device to a physical device */
#define IPSEC_SET_DEV (SIOCDEVPRIVATE)

==> Result: ipsec bombs out trying to handle SIOCDEVPRIVATE ioctl for 
(already configured) ipsec0.

which leaves us with the question: what's the right fix?
	a) remove the fallback SIOCDEVPRIVATE call from snmpd
	b) add a SIOCGMIIREG ioctl to ipsec
	c) handle the spurious SIOCDEVPRIVATE ioctl more gracefully in ipsec.

I've just verified that removing the fallback to SIOCDEVPRIVATE from 
snmp works as a fix, no more problems with openswan+snmp daemon. What I 
can't say if this might impact snmpd functionality when used with older 
kernels/drivers that implement only SIOCDEVPRIVATE.

Bye, Martin