taglinefilesource code
link345include/linux/skbuff.hstruct sk_buff    * volatile link3;
link3335net/inet/af_inet.cskb2 = skb->link3;
link31753net/inet/ip.cnewskb->link3=NULL;
link31895net/inet/ip.cif (skb->link3 != NULL)
link31898net/inet/ip.cskb->link3 = NULL;
link31907net/inet/ip.csk->send_tail->link3 = skb;
link3429net/inet/skbuff.cskb->link3 = NULL;
link3506net/inet/skbuff.cn->link3=NULL;
link3507net/inet/tcp.cskb = skb->link3;
link33219net/inet/tcp.cskb2 = skb->link3;
link33220net/inet/tcp.cskb->link3 = NULL;
link33246net/inet/tcp.csk->send_tail->link3 = skb;
link33249net/inet/tcp.cskb->link3 = NULL;
link33355net/inet/tcp.cif (sk->send_head->link3 &&
link33356net/inet/tcp.cafter(sk->send_head->h.seq, sk->send_head->link3->h.seq)) 
link33382net/inet/tcp.cif (sk->send_head->link3)  /* Any more queued retransmits? */
link33450net/inet/tcp.csk->send_head = oskb->link3;