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: lwip-users-bounces+address@hidden [mailto:lwip-users-bounces+address@hidden
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
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 <address@hidden> wrote:
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):
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(): 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:
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
6614 Astro Court, Mississauga
Ontario, Canada L5N 7J2
home: 905 824 7159
cell: 416 457 7163
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