Re: [PATCH] User mode linux bump maximum MTU tuntap interface [RESAND]

On 02/07/2019 15:40, Richard Weinberger wrote:

CC'ing um folks.

On Tue, Jul 2, 2019 at 3:01 PM Алексей [off-list ref] wrote:

quoted

Hello, the parameter  ETH_MAX_PACKET limited to 1500 bytes is the not
support jumbo frames.

This patch change ETH_MAX_PACKET the 65535 bytes to jumbo frame support
with user mode linux tuntap driver.


PATCH:

-------------------


diff -ruNP ../linux_orig/linux-5.1/arch/um/include/shared/net_user.h
./arch/um/include/shared/net_user.h

--- a/arch/um/include/shared/net_user.h    2019-05-06 00:42:58.000000000
+0000
+++ b/arch/um/include/shared/net_user.h    2019-07-02 07:14:13.593333356
+0000

@@ -9,7 +9,7 @@
  #define ETH_ADDR_LEN (6)
  #define ETH_HEADER_ETHERTAP (16)
  #define ETH_HEADER_OTHER (26) /* 14 for ethernet + VLAN + MPLS for

crazy people */
-#define ETH_MAX_PACKET (1500)
+#define ETH_MAX_PACKET (65535)

  #define UML_NET_VERSION (4)

-------------------

The vector version for tap already allows mtu > 1500. It does not have a 
check to limit it to 65535 max though and it should.

I will add this one to the queue of stuff for the network drivers. IMHO 
we should start migrating some of the older ones to vector IO.

-- 
Anton R. Ivanov
https://www.kot-begemot.co.uk/