OS: RHEL 2.6.32
the command "ifconfig vEth0 up" to start the KNI interface fails a few times with
SIOCSIFFLAGS: Timer expired
After some time (around 1 minute) the command "ifconfig vEth0 up" works OK.
It looks that it is linked to the IPv6 auto configuration as the kernel syslog shows the message kernel: vEth0: no IPv6 routers present.
I am using the DPDK application on IPv4 and there is no IPv6 router in the LAN.
Question how do I deactivate the IPv6 auto configuration for the KNI interface ?
I tried to create a entry in /etc/sysconfig/ifcfg_vETh0 with IPV6INIT="no" and IPV6_AUTOCONF="no" without success.
I guess that the kernel does not apply this setting as at boot time the the DPDK application does not run.
Interestingly, it seems that the tap/tun interface does not have this problem.
I am wondering how Linux avoid doing the IPv6 auto configuration on a tap/tun interface ?
I solve my problem.
The issue is the KNI function
* It is called in the same lcore of receiving packets, and polls the request
* mbufs sent from kernel space. Then analyzes it and calls the specific
* actions for the specific requests. Finally constructs the response mbuf and
* puts it back to the resp_q.
static int kni_request_handler(struct rte_kni *kni)
This function is only called by
unsigned rte_kni_tx_burst(struct rte_kni *kni, struct rte_mbuf **mbufs, unsigned num)
So if there is no incoming PDU from the NIC to be sent to the Linux kernel, the function rte_kni_tx_burst is not called.
The KNI layer does not read the request PDU so does not get the if_up message so does not answer to the kernel module so the KNI kernel module replies to IP with a time out.
Call regularly rte_kni_tx_burst(kni, NULL, 0).