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<br>Sure. I'll send the man page updates.<br><br>Regarding the overloading of the server name parameter:<br> are you saying that we should have a version of the dhcp-boot option like:<br><br>dhcp-boot=/var/ftpd/pxelinux.0,boothost,boothost<br><br>and take the second 'boothost' (3rd parameter) to indicate that<br>it be resolved and a resultant address returned as a tftp<br>server address ?<br><br>cheers<br>Sushil.<br><br><br>> Subject: Re: [Dnsmasq-discuss] Enable dnsmasq to return addresses of multiple tftp servers in cycle<br><div>> From: simon@thekelleys.org.uk<br>> Date: Sat, 18 Jun 2011 22:44:25 +0100<br>> To: sushil_agrawal@hotmail.com; dnsmasq-discuss@lists.thekelleys.org.uk<br>> <br>> Sushil Agrawal <sushil_agrawal@hotmail.com> wrote:<br>> <br>> ><br>> ><br>> >Hi All,<br>> ><br>> >The attached patch enables dnsmasq(8) to return the ip addresses<br>> >of multiple tftp servers (for pxe boot) having a single alias<br>> >name (thru the /etc/hosts) in round robin fashion.<br>> ><br>> >We have a virtual environment where there are some managed hosts<br>> >running kvm hypervisor and some > 150 virtual machines<br>> >carved out of these hosts. All these virtual machines are thin<br>> >clients which boot of the net using pxe. The arrangement is such<br>> >that all of these machines boot at the same time and in order to<br>> >balance the load on the tftp server, we planned to have multiple<br>> >tftp servers (on these managed hosts themselves) running.<br>> ><br>> >dnsmasq currently returns only one address for tftp server<br>> >which it finds in the dhcp-boot option in the dnsmasq.conf<br>> >file. Although there is a provision for specifying the<br>> >tftp server name there but it is not used. We made<br>> >use of this name as an alias for multiple tftp servers<br>> >(using /etc/hosts) and then return the resolved addresses<br>> >one by one in cycle.<br>> ><br>> >The function cache_find_by_name() already takes care<br>> >of all this and all we had to do was to just call<br>> >it in dhcp_reply() to get one address and return<br>> >that as tftp address.<br>> ><br>> >If the tftp server address is specified in the dhcp-boot<br>> >option then that address is returned always. If address<br>> >is not specified and name is specified then this cyclic<br>> >stuff is done. This solution is working for us and hope it<br>> >will be useful to others.<br>> ><br>> ><br>> >Following is the patch (also attached) based on<br>> >dnsmasq-2.57:<br>> ><br>> >................................................................<br>> ><br>> >--- dnsmasq-2.57.origg/src/rfc2131.c 2011-02-17 21:00:15.000000000<br>> >+0530<br>> >+++ dnsmasq-2.57/src/rfc2131.c 2011-06-18 17:48:59.000000000 +0530<br>> >@@ -829,8 +829,23 @@<br>> > and set discovery_control = 8 */<br>> > if (boot)<br>> > {<br>> >- if (boot->next_server.s_addr)<br>> >+ if (boot->next_server.s_addr) {<br>> > mess->siaddr = boot->next_server;<br>> >+ } else if (boot->sname) {<br>> >+<br>> >+ /*<br>> >+ * If the pxe server name is given in the conf then<br>> >+ * cycle thru its addresses.<br>> >+ */<br>> >+<br>> >+ struct crec *crecp;<br>> >+ time_t now = dnsmasq_time();<br>> >+ crecp = cache_find_by_name(NULL, boot->sname, now,<br>> >+ F_DHCP | F_HOSTS);<br>> >+ if (crecp) {<br>> >+ mess->siaddr = *(struct in_addr*)&crecp->addr;<br>> >+ }<br>> >+ }<br>> > <br>> > if (boot->file)<br>> > strncpy((char *)mess->file, boot->file, sizeof(mess->file)-1);<br>> >@@ -2222,8 +2237,23 @@<br>> > strncpy((char *)mess->file, boot->file, sizeof(mess->file)-1);<br>> > }<br>> > <br>> >- if (boot->next_server.s_addr)<br>> >+ if (boot->next_server.s_addr) {<br>> > mess->siaddr = boot->next_server;<br>> >+ } else if (boot->sname) {<br>> >+<br>> >+ /*<br>> >+ * If the pxe server name is given in the conf then<br>> >+ * cycle thru its addresses.<br>> >+ */<br>> >+<br>> >+ struct crec *crecp;<br>> >+ time_t now = dnsmasq_time();<br>> >+ crecp = cache_find_by_name(NULL, boot->sname, now,<br>> >+ F_DHCP | F_HOSTS);<br>> >+ if (crecp) {<br>> >+ mess->siaddr = *(struct in_addr*)&crecp->addr;<br>> >+ }<br>> >+ }<br>> > }<br>> > else<br>> > /* Use the values of the relevant options if no dhcp-boot given and<br>> >................................................................<br>> ><br>> >Sushil.<br>> ><br>> ><br>> > _______________________________________________<br>> >Dnsmasq-discuss mailing list<br>> >Dnsmasq-discuss@lists.thekelleys.org.uk<br>> >http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss<br>> <br>> This looks like a great idea, but overloading the server name parameter is not correct. That can be used for other things. The correct way to do this is to check if a name is supplied instead of an address in dhcp-boot and act accordingly. That will need some code in options.c and elaboration of the dhcp boot data structure. <br>> <br>> A general observation for patch submitters. I'm much more likely to look kindly on a patch if it includes documentation, ie a patch to the man page.<br>> <br>> I'm away from home at the moment, so further action on this may have to wait until next week.<br>> <br>> Cheers, <br>> <br>> Simon.<br></div> </div></body>
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