When erspan_rcv call return PACKET_REJECT, we shoudn't call ipgre_rcv to
process packets again, instead send icmp unreachable message in error
path.
Fixes: 84e54fe0a5ea ("gre: introduce native tunnel support for ERSPAN") Acked-by: William Tu <u9012063@gmail.com> Cc: William Tu <u9012063@gmail.com> Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com> Signed-off-by: David S. Miller <davem@davemloft.net>