How to send ethernet frames from one veth to another?

I have two veth pairs (veth1, veth1_0) and (veth2, veth2_0). veth1_0 and veth2_0 are in the default namespace ns0, veth1 is in namespace ns1 and veth2 in namespace ns2. I want to communicate between different namespaces. So I use veth1_0 to send an ethernet frame to veth2_0(use pcap_sendpacket), hoping I can capture the packet at veth2. And in my output, I can capture the packet in namespace 1 at veth1; but fail to do in namespace 2 at veth2. I wonder if it's possible to accomplish the communication in this way; or maybe there are other methods.