[cip-dev] [PATCH 4.4.y V2] net: ipconfig: Support using "delayed" DHCP replies
pavel at denx.de
Thu May 2 21:19:29 UTC 2019
> The dhcp code only waits 1s between sending DHCP requests on different
> devices and only accepts an answer for the device that sent out the last
> request. Only the timeout at the end of a loop is increased iteratively
> which favours only the last device. This makes it impossible to work
> with a dhcp server that takes little more than 1s connected to a device
> that is not the last one.
> Instead of also increasing the inter-device timeout, teach the code to
> handle delayed replies.
> To accomplish that, make *ic_dev track the current ic_device instead of
> the current net_device and adapt all users accordingly. The relevant
> change then is to reset d to ic_dev on a reply to assert that the
> followup request goes through the right device.
In the end I decided to apply this one. It is true that the alternate
fix is one-liner, but I would not be sure if other timing parameters
need changing, and would not have a good way to test that.
> --- a/net/ipv4/ipconfig.c
> +++ b/net/ipv4/ipconfig.c
> @@ -94,7 +94,6 @@
> /* Define the timeout for waiting for a DHCP/BOOTP/RARP reply */
> #define CONF_OPEN_RETRIES 2 /* (Re)open devices twice */
> #define CONF_SEND_RETRIES 6 /* Send six requests per open */
> -#define CONF_INTER_TIMEOUT (HZ) /* Inter-device timeout: 1 second */
> #define CONF_BASE_TIMEOUT (HZ*2) /* Initial timeout: 2 seconds */
> #define CONF_TIMEOUT_RANDOM (HZ) /* Maximum amount of randomization */
> #define CONF_TIMEOUT_MULT *7/4 /* Rate of timeout growth */
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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