taglinefilesource code
send_tail199include/net/sock.hstruct sk_buff    * volatile send_tail;
send_tail443net/ipv4/ip_output.csk->send_tail = skb;
send_tail448net/ipv4/ip_output.csk->send_tail->link3 = skb;
send_tail449net/ipv4/ip_output.csk->send_tail = skb;
send_tail399net/ipv4/tcp_input.cnewsk->send_tail = NULL;
send_tail543net/ipv4/tcp_input.csk->send_tail = NULL;
send_tail576net/ipv4/tcp_input.csk->send_tail = skb;
send_tail580net/ipv4/tcp_input.csk->send_tail->link3 = skb;
send_tail581net/ipv4/tcp_input.csk->send_tail = skb;
send_tail663net/ipv4/tcp_input.cif (sk->send_tail == NULL || sk->send_head == NULL) 
send_tail666net/ipv4/tcp_input.csk->send_tail = NULL;
send_tail839net/ipv4/tcp_input.csk->send_tail = NULL;