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) -------------------
