taglinefilesource code
ow_size4954net/ipv4/tcp.cunsigned long win_size, ow_size;
ow_size5048net/ipv4/tcp.cow_size = skb->len - win_size - 
ow_size5051net/ipv4/tcp.cmemmove(tcp_data_start, tcp_data_start + win_size, ow_size);