1.\" 2.\" This file and its contents are supplied under the terms of the 3.\" Common Development and Distribution License ("CDDL"), version 1.0. 4.\" You may only use this file in accordance with the terms of version 5.\" 1.0 of the CDDL. 6.\" 7.\" A full copy of the text of the CDDL should have accompanied this 8.\" source. A copy of the CDDL is also available via the Internet at 9.\" http://www.illumos.org/license/CDDL. 10.\" 11.\" 12.\" Copyright 2016 Joyent, Inc. 13.\" 14.Dd June 02, 2016 15.Dt MAC_MAXSDU_UPDATE 9F 16.Os 17.Sh NAME 18.Nm mac_maxsdu_update 19.Nd indicate that a device's maximum data size has changed 20.Sh SYNOPSIS 21.In sys/mac_provider.h 22.Ft int 23.Fo mac_maxsdu_update 24.Fa "mac_handle_t mh" 25.Fa "uint_t sdu" 26.Fc 27.Sh INTERFACE LEVEL 28illumos DDI specific 29.Sh PARAMETERS 30.Bl -tag -width Fa 31.It Fa mh 32The MAC handle obtained from a call to 33.Xr mac_register 9F . 34.It Fa sdu 35An integer representing the maximum size data payload. 36.El 37.Sh DESCRIPTION 38The 39.Fn mac_maxsdu_update 40function is used to inform the MAC layer that the device represented by 41the handle 42.Fa mh 43has changed the largest size frame that it can transmit, also known as 44its Send Data Unit (SDU). This should be called when the device's MTU 45has been requested to be changed when a driver's 46.Xr mac_setprop 9E 47entry point has been called with the property 48.Sy MAC_PROP_MTU 49or some other device-related event occurring. 50.Pp 51The 52.Fa sdu 53represents the size of the largest payload ignoring the size of its own 54headers or any margin. For example, for an Ethernet-based device, this 55size should not include the Ethernet header or any VLAN tags. 56.Pp 57Through VNICs and other virtual data links, many different devices may 58be using a single physical device and have their own MTUs. The system 59takes care of those concerns and will not ask a device driver to update 60the MTU without verifying this. 61.Sh RETURN VALUES 62Upon successful completion, the 63.Fn mac_maxsdu_update 64function returns 65.Sy 0 . 66Otherwise, a non-negative error is returned. 67.Sh EXAMPLES 68For an example of how a device driver should use the 69.Fn mac_maxsdu_update 70function, see the 71.Sx EXAMPLES 72section in 73.Xr mac_setprop 9E . 74.Sh ERRORS 75The 76.Fn max_maxsdu_update 77function may fail if: 78.Bl -tag -width Er 79.It Er EINVAL 80The specified 81.Fa sdu 82is lower than the minimum SDU of the device. 83.El 84.Sh SEE ALSO 85.Xr mac 9E , 86.Xr mac_setprop 9E , 87.Xr mac_register 9F 88