Maybe someone else could also comment on this and let me know if I am wrong but as far as I know you don’t have to do anything once the IP address is obtained from DHCP. I don’t think you should ever be calling dhcp_stop() unless maybe you really don’t want to use dhcp anymore. Maybe they are incorrectly doing that in the example to free up the udp pcb being used by dhcp. But I don’t think dhcp_stop() should be called because the dhcp client should continue to run to renew IP leases when they expire and stay registered with the dhcp server.
As far as I know all you have to do is call dhcp_start() (which also ends up calling autoip_start() if AUTOIP is enabled) then just call dhcp_fine_tmr(),dhcp_coarse_tmr(), and autioip_tmr() at their respective intervals. Once the address is obtained, your netif will be updated with that address – you don’t have to do anything. From: [email protected] [mailto:[email protected]] On Behalf Of Robert Deschambault Sent: Thursday, June 18, 2015 8:29 AM To: Mailing list for lwIP users Subject: Re: [lwip-users] Strategy Question for DHCP Hi, Ok, did another little experiment and I notice that if I don't call dhcp_stop() in the DHCP state machine when the IP address gets assigned I can ping my target when I use AUTOIP. Autoip is in state 3 (bound) and everything is fine. When I call dhcp_stop() at any time, autoip goes to state 0 (stop) and I lose comms with the target. My question is this: What should I be doing once the IP address is assigned by either DHCP or AUTOIP in coop mode? Any call to dhcp_stop() seems to be the wrong answer. But all the examples I have seen for an STM32F4xx call that function once the IP address has been assigned. Any comments? On Wed, Jun 17, 2015 at 8:28 PM, Robert Deschambault <[email protected]<mailto:[email protected]>> wrote: Hi, I did a quick test to see when the autoip state is set to stop. It looks like that when the IP address becomes non-zero, the DHCP code recognizes the assignment and makes a call to dhcp_stop() which I believe is calling autoip_stop() function coop mode. Here is what the printf debug looks like at assignment (my code is also printing stuff too and please remember I have modified the default IP address pool for my application): ... dhcp_discover() transaction id xid(abcd0001) dhcp_discover: making request dhcp_discover: realloc()ing dhcp_discover: sendto(DISCOVER, IP_ADDR_BROADCAST, DHCP_SERVER_PORT) dhcp_discover: deleting()ing dhcp_discover: SELECTING dhcp_discover(): set request timeout 16000 msecs autoip_tmr() AutoIP-State: 2, ttw=6 autoip_tmr() AutoIP-State: 2, ttw=5 autoip_tmr() AutoIP-State: 2, ttw=4 autoip_tmr() AutoIP-State: 2, ttw=3 autoip_tmr() AutoIP-State: 2, ttw=2 autoip_tmr() AutoIP-State: 2, ttw=1 autoip_tmr() AutoIP-State: 2, ttw=0 autoip_bind(netif=20000778) cd0 192.168.252.11 autoip_tmr() AutoIP-State: 2, ttw=20 autoip_tmr() AutoIP-State: 2, ttw=19 MAIN: Network assigned by DHCP server: dhcp_stop() MAIN: IP: 192.168.252.11 MAIN: SN: 255.255.255.0 MAIN: GW: 192.168.252.1 autoip_tmr() AutoIP-State: 0, ttw=18 autoip_tmr() AutoIP-State: 0, ttw=18 autoip_tmr() AutoIP-State: 0, ttw=18 ... after this the last line is repeated over and over again. ttw always stays at 18 and the state is always 0 (stop). I don't know if this the expected behavior? -- Bob Deschambault -- Bob Deschambault 6614 Astro Court, Mississauga Ontario, Canada L5N 7J2 home: 905 824 7159 cell: 416 457 7163 twitter: @rdeschambault 1Fm3QkinyqiMbpnvSZMLM1AyjBvbuYeTBE ________________________________ Confidentiality Notice: This e-mail may contain confidential and privileged material for the sole use of the intended recipient(s). Any review, use, distribution or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive from the recipient), please contact the sender by reply e-mail and delete all copies of the message.
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