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Diffstat (limited to 'source/nameannounce.doc')
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diff --git a/source/nameannounce.doc b/source/nameannounce.doc deleted file mode 100644 index e04a59209a1..00000000000 --- a/source/nameannounce.doc +++ /dev/null @@ -1,265 +0,0 @@ -/* - Unix SMB/Netbios documentation. - Version 0.2 - Copyright (C) Luke Leighton Andrew Tridgell 1996 - - This program is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 2 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program; if not, write to the Free Software - Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - - Document name: nameannounce.doc - - Revision History: - - 0.0 - 02jul96 : lkcl@pires.co.uk - created - - 0.1 - 22jul96 : Andrew.Tridgell@anu.edu.au - tridge's comments on first revision - - 0.2 - 05aug96 : lkcl@pires.co.uk - actioned tridge comments about pdc -> domain master - documented NAME_QUERY_ANNOUNCE_HOST - -*/ - - -this module deals with announcements: the sending of announcement requests -and the sending of announcements either to refresh other servers' records -or as a response to announcement requests. - - -/************************************************************************* - announce_master() - *************************************************************************/ - -this function is responsible for announcing samba as a master browser -to all known domain masters. - -this announcement is sent out at CHECK_TIME_MST_ANNOUNCE minute -intervals, only if samba is a master browser on one or more of -its local interfaces. - -if no domain controller has been specified (lp_domain_controller()) -samba goes through its list of servers looking for domain master -browsers. when it finds one (other than itself) it will either -initiate a NAME_QUERY_PDC_SRV_CHK by broadcast or with a WINS -server. this will result in a NAME_STATUS_PDC_SRV_CHK, which -will result in a sync browse list and an announcement -ANN_MasterAnnounce being sent (see sync_server()). - -if a domain controller has been specified, samba will search for -a domain master browser for its workgroup (either by directed -packet or by broadcast if it cannot resolve the domain controller -name using DNS), which results in the same action as listed above. - ------------- -NOTE FROM TRIDGE: - -PDC in the above should really be DMB (domain master browser). They -might be separate entities. - -I also propose a simpler scheme :-) - -If a DMB is not configured with lp_domain_controller() (perhaps -renamed to lp_domain_master()?) then just don't do master -announcements. Remember that most peoples networks are very simple and -don't need DMB capabilities. Those that do need them will have more -complex network topologies and they really need to choose themselves -which box will act as the "hub" for netbios name resolution. Doing it -via name queries will just lead to lag and propogation delays, because -if two parts of the net choose different DMBs then the data will be -very slow to propoogate. - -If a DMB is configured then just send the master announcemnt to that -box! Thats all that needs to be done. Just send a udp 138 packet and -forget it. If the recipient is indeed a DMB (as it should be if the -config file is correct) then it should initiate a browse list sync -with us at some later time, but that is take care of by smbd and nmbd -doesn't even need to know it happened. - -Additionally, if a DMB is configured we need to sync our workgroup -list and server list with them occasionally. Note that this is only -time a non-DMB should do a browse sync, and it should only do it with -a DMB. Essentially WAN based netbios is just a simple star. There is a -DMB in the centre, and the individual master browsers for each subnet -talk to it, but never talk to each other. If they start talking to -each other then the network load will go as the square of the number -of machines, which will result in meltdown :-) -------------- - - -/************************************************************************* - announce_host() - *************************************************************************/ - -this complex-looking function is responsible for announcing samba's -existence to other servers by broadcast. the actual announcement -is carried out by announce_server(). - -the time period between samba's announcement will stretch from one -minute to twelve minutes by one minute. if samba has received an -announce request from a master browser, then it should answer at -any random interval between zero and thirty seconds after the -request is received. this is to ensure that the master browser -does not get overloaded with responses! - - -/************************************************************************* - announce_server() - *************************************************************************/ - -this function is responsible for sending announcement packets. -these packets are received by other servers, which will then -update their records accordingly: what services we have, our -name, our comment field and our time to live (to name a few). - -if samba is a non-master then we need to see if there is a -domain master (on a remote subnet) that we need to announce to -it. - -if samba is not the WINS server (and it is using another -WINS server) then we need to do a name query to the WINS -server to ask it what the domain controller is. this is done -using a samba 'state' NAME_QUERY_ANNOUNCE_HOST, which passes -sufficient information on to be able to carry out the -host announcement using a unicasted do_announce_host() if and -when a reply comes back. if there is no reply to the name query, -this is not necessarily an error - there may genuinely be no -domain master currently up and running for samba's workgroup. - -if samba is a WINS server, then samba will need to look up the -domain controller for its workgroup in its WINS records. an -over-cautious samba could carry out a name query on that -domain controller to make sure that it is alive and that samba's -WINS records are up-to-date. in any event, it will send a unicast -do_announce_host() to inform the domain master browser, if one -exists, of samba's server status. - -if we are a master browser, then using do_announce_host() we -must send a broadcast announcement on the local interface -notifying members of that workgroup that we are their master -browser, and another announcement indicating to all backup -browsers and master browsers that we are a master browser. - -(note: if another master browser receives this broadcasted -announcement and thinks that it is also the master browser -for this workgroup, it stops being a master browser and forces -an election). - -if we are not a master browser, then we send a broacast -announcement notifying the master browser that we are a member -of its workgroup, on the local interface. - - -/************************************************************************* - remove_my_servers() - *************************************************************************/ - -this function is responsible for informing other servers that -samba is about to go down. it announces, on all subnets, that -samba's time to live is zero and that it has no services. - - -/************************************************************************* - do_announce_host() - *************************************************************************/ - -this function is responsible for sending out an announcement -MAILSLOT browse packet. it contains information such as the -time to live, name of the server, services that the server -offers etc. - -the format of this MAILSLOT browse packet is described in -draft-heizer-cifs-v1-spec-00.txt 3.9.50.4.1 page 165-6. - - -/************************************************************************* - announce_backup() - *************************************************************************/ - -this function is responsible for getting master browsers and domain -controllers to send us lists of backup servers. this is done by -sending an ANN_GetBackupListReq browse mailslot. - -the local master browser, or domain master browser, should respond -with an ANN_GetBackupListResp browse mailslot containing the list -of backup servers. - --------------- -NOTE FROM TRIDGE: I don't see why nmbd should ever send one of -these. The only reason I can see for any part of Samba sending one of -these is if we implement it in smbclient. - -This packet is used to request a list of backup master browsers from -the master browser. It is used by clients (not servers!) to spread the -browse load over more than one server. The only server that needs to -know what the list of backups is is the master browser, and as it is -also responsible for generating this list it will never ask anyone -else for it. --------------- - - -/************************************************************************* - sync_server() - *************************************************************************/ - -this function is responsible for initiating a sync browse list -sequence and, if necessary, carrying out an ANN_MasterAnnouncement -to the domain master browser (that we are also sync'ing browse lists -with). - -see nameservresp.c:response_name_status_check(). - - -/************************************************************************* - announce_request() - *************************************************************************/ - -this function is responsible for sending an announcement request to -another server. this server should respond with an announcement. - -if the announce request is sent to WORKGROUP(0x1e) then members of -the workgroup will respond (with ANN_HostAnnounce packets) - -if the announce request is sent to WORKGROUP(0x1d) then the master -browser of the workgroup should respond (ANN_LocalMasterAnnounce). -this is untested. - -if the announce request is sent to ^1^2__MSBROWSE__^2(0x1) then -(and this is pure speculation), all backup browsers and master -browsers should respond with ANN_DomainAnnounce packets. -this is untested. - ------------ -NOTE FROM TRIDGE: - -I had great trouble getting machines to actually respond to this -packet. Either we have the format wrong or MS chose not to implement -it. - -Not implementing it doesn't break anything, it just means a new master -browser won't get a complete server list as quickly. - -Also note that this packet should be used as little as possible as it -could easily cause meltdown if too many servers used it. Imagine a -dozen samba servers on a net all sending this packet! You will get 244 -responses all within 30 seconds. now imagine 50 samba servers .... - -So I think we should restrict ourselves to sending this packet only if -we are already the master browser for a workgroup. We could send a -single "announce request" when we become the master, just to prime our -server lists. From then on the normal announce cycles should take care -of keeping it uptodate. ------------ - |