[ovs-dev] [PATCH net] geneve: Refine MTU limit

Jesse Gross jesse at kernel.org
Tue Feb 16 18:32:15 UTC 2016


On Tue, Feb 16, 2016 at 4:33 AM, David Wragg <david at weave.works> wrote:
> diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
> index 028e387..f57f9bc 100644
> --- a/drivers/net/geneve.c
> +++ b/drivers/net/geneve.c
> @@ -37,6 +37,9 @@ MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
>
>  #define GENEVE_VER 0
>  #define GENEVE_BASE_HLEN (sizeof(struct udphdr) + sizeof(struct genevehdr))
> +#define GENEVE_MAX_OPTIONS_LEN (63 * 4)
> +#define GENEVE_MAX_MTU (IP_MAX_MTU - sizeof(struct iphdr) - GENEVE_BASE_HLEN \
> +                                               - GENEVE_MAX_OPTIONS_LEN)

In addition to Tom's comment about taking into account
dev->hard_header_len, can you please not include
GENEVE_MAX_OPTIONS_LEN in the MTU calculation based on the discussion
on the other thread? Otherwise, you are excluding some potentially
valid configurations.



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