taglinefilesource code
send_tail138include/net/sock.hstruct sk_buff    * volatile send_tail;
send_tail447net/ipv4/ip_output.csk->send_tail = skb;
send_tail452net/ipv4/ip_output.csk->send_tail->link3 = skb;
send_tail453net/ipv4/ip_output.csk->send_tail = skb;
send_tail3009net/ipv4/tcp.cnewsk->send_tail = NULL;
send_tail3492net/ipv4/tcp.csk->send_tail = NULL;
send_tail3529net/ipv4/tcp.csk->send_tail = skb;
send_tail3533net/ipv4/tcp.csk->send_tail->link3 = skb;
send_tail3534net/ipv4/tcp.csk->send_tail = skb;
send_tail3546net/ipv4/tcp.cif (sk->send_tail == NULL || sk->send_head == NULL) 
send_tail3549net/ipv4/tcp.csk->send_tail = NULL;
send_tail3747net/ipv4/tcp.csk->send_tail = NULL;