CentOS aims at being 100% binary compatible with the upstream vendor (including bugs). To accommodate users needs, the CentOS team offers the centosplus kernel which includes features that are not in the distro kernel. It has a number of options (mostly device drivers) enabled and also has patches that correct known issues.

Recently, it was reported that the centosplus kernel had a problem with certain versions of VMware products as seen in this CentOS forum thread.

Specifically, building the vmnet module on a host fails with the error:

/tmp/vmware-config2/vmnet-only/compat_netdevice.h:273: error: redefinition of ‘struct napi_struct’

Apparently, somewhere in the kernel source that was added in the centosplus kernel, there is that definition and it is conflicting with the VMware code.

It turned out that the problem exists in the VM guest as well: building of the vmxnet modules fails with the same error. The fix, in both cases, is to untar:

/usr/lib/vmware/modules/source/vmnet.tar (host)
/usr/lib/vmware-tools/modules/source/vmxnet.tar (guest)

and comment out the following block in compat_netdevice.h:

struct napi_struct {
    int dummy;
 };

More details can be found in the CentOS bug tracker.