taglinefilesource code
send_tail642net/inet/af_inet.csk->send_tail = NULL;
send_tail1914net/inet/ip.csk->send_tail = skb;
send_tail1919net/inet/ip.csk->send_tail->link3 = skb;
send_tail1920net/inet/ip.csk->send_tail = skb;
send_tail95net/inet/sock.hstruct sk_buff    * volatile send_tail;
send_tail2238net/inet/tcp.cnewsk->send_tail = NULL;
send_tail2785net/inet/tcp.csk->send_tail = NULL;
send_tail2822net/inet/tcp.csk->send_tail = skb;
send_tail2826net/inet/tcp.csk->send_tail->link3 = skb;
send_tail2827net/inet/tcp.csk->send_tail = skb;
send_tail2839net/inet/tcp.cif (sk->send_tail == NULL || sk->send_head == NULL) 
send_tail2842net/inet/tcp.csk->send_tail = NULL;
send_tail3010net/inet/tcp.csk->send_tail = NULL;