taglinefilesource code
send_tail104include/net/sock.hstruct sk_buff    * volatile send_tail;
send_tail673net/ipv4/af_inet.csk->send_tail = NULL;
send_tail1840net/ipv4/ip.csk->send_tail = skb;
send_tail1845net/ipv4/ip.csk->send_tail->link3 = skb;
send_tail1846net/ipv4/ip.csk->send_tail = skb;
send_tail2695net/ipv4/tcp.cnewsk->send_tail = NULL;
send_tail3168net/ipv4/tcp.csk->send_tail = NULL;
send_tail3205net/ipv4/tcp.csk->send_tail = skb;
send_tail3209net/ipv4/tcp.csk->send_tail->link3 = skb;
send_tail3210net/ipv4/tcp.csk->send_tail = skb;
send_tail3222net/ipv4/tcp.cif (sk->send_tail == NULL || sk->send_head == NULL) 
send_tail3225net/ipv4/tcp.csk->send_tail = NULL;
send_tail3416net/ipv4/tcp.csk->send_tail = NULL;