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</o:shapelayout></xml><![endif]--></head><body lang=ZH-CN link=blue vlink=purple style='text-justify-trim:punctuation'><div class=WordSection1><p class=MsoNormal><span lang=EN-US>Recently I begin to read source code of bind9. I am puzzled by following questions:<o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:42.0pt;text-indent:-21.0pt;mso-list:l0 level2 lfo1'><![if !supportLists]><span lang=EN-US><span style='mso-list:Ignore'>a)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US>I found that the call trace is : load_configuration </span><span lang=EN-US style='font-family:Wingdings'>¨¤</span><span lang=EN-US> scan_interfaces </span><span lang=EN-US style='font-family:Wingdings'>¨¤</span><span lang=EN-US> ns_interfacemgr_scan </span><span lang=EN-US style='font-family:Wingdings'>¨¤</span><span lang=EN-US> ns_interfacemgr_scan0 </span><span lang=EN-US style='font-family:Wingdings'>¨¤</span><span lang=EN-US> do_scan </span><span lang=EN-US style='font-family:Wingdings'>¨¤</span><span lang=EN-US> ns_interface_setup </span><span lang=EN-US style='font-family:Wingdings'>¨¤</span><span lang=EN-US> ns_interface_listenudp </span><span lang=EN-US style='font-family:Wingdings'>¨¤</span><span lang=EN-US> dns_dispatch_getudp_dup </span><span lang=EN-US style='font-family:Wingdings'>¨¤</span><span lang=EN-US> dispatch_createudp </span><span lang=EN-US style='font-family:Wingdings'>¨¤</span><span lang=EN-US> get_udpsocket </span><span lang=EN-US style='font-family:Wingdings'>¨¤</span><span lang=EN-US> open_socket, then finally perform systemcall socket and bind. But I don¡¯t find when and how these sock->fd are added to epoll? <o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:42.0pt;text-indent:-21.0pt;mso-list:l0 level2 lfo1'><![if !supportLists]><span lang=EN-US><span style='mso-list:Ignore'>b)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US>I only find manager->fds[0] is added to epoll when setup_watcher(). It seems that someone can call select_poke to trigger watcher thread to watch_fd. But ,by far , created fds are not added to epoll , how is udp packet received? Who will call select_poke()?<o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:42.0pt;text-indent:-21.0pt;mso-list:l0 level2 lfo1'><![if !supportLists]><span lang=EN-US><span style='mso-list:Ignore'>c)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US>What does dns_dispatch do ? why multi dns_dispatch are created for one interface?<o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:42.0pt;text-indent:-21.0pt;mso-list:l0 level2 lfo1'><![if !supportLists]><span lang=EN-US><span style='mso-list:Ignore'>d)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US>What does timermgr and all kinds of timer do ?<o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:21.0pt;text-indent:0cm'><span lang=EN-US><o:p> </o:p></span></p><p class=MsoListParagraph style='margin-left:21.0pt;text-indent:0cm'><span lang=EN-US>I am extremely anxious to find the answer, your reply are highly appreciated. <o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:21.0pt;text-indent:0cm'><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p></div></body></html>