| xnb.4 (3e85ab1008d682f64a8857f52fd49f577d6478e8) | xnb.4 (12afe06c06846b49eab319388a689123dd7860a4) |
|---|---|
| 1.\" Copyright (c) 2012 Spectra Logic Corporation 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions, and the following disclaimer, --- 70 unchanged lines hidden (view full) --- 79netfront and netback. 80Mostly useful for debugging, but can also be used to 81get traffic statistics. 82.It Va dev.xnb.%d.unit_test_results 83Runs a builtin suite of unit tests and displays the results. 84Does not affect the operation of the driver in any way. 85Note that the test suite simulates error conditions; this will result in 86error messages being printed to the system system log. | 1.\" Copyright (c) 2012 Spectra Logic Corporation 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions, and the following disclaimer, --- 70 unchanged lines hidden (view full) --- 79netfront and netback. 80Mostly useful for debugging, but can also be used to 81get traffic statistics. 82.It Va dev.xnb.%d.unit_test_results 83Runs a builtin suite of unit tests and displays the results. 84Does not affect the operation of the driver in any way. 85Note that the test suite simulates error conditions; this will result in 86error messages being printed to the system system log. |
| 87.Sh SEE ALSO 88.Xr arp 4 , 89.Xr netintro 4 , 90.Xr ng_ether 4 , 91.Xr xen 4 , 92.Xr ifconfig 8 93.Sh HISTORY 94The 95.Nm 96device driver first appeared in 97.Fx 10.0 . 98.Sh AUTHORS 99The 100.Nm 101driver was written by 102.An Alan Somers 103.Aq alans@spectralogic.com 104and 105.An John Suykerbuyk 106.Aq johns@spectralogic.com |
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| 87.Sh CAVEATS 88Packets sent through Xennet pass over shared memory, so the protocol includes 89no form of link-layer checksum or CRC. 90Furthermore, Xennet drivers always report to their hosts that they support 91receive and transmit checksum offloading. 92They "offload" the checksum calculation by simply skipping it. 93That works fine for packets that are exchanged between two domains on the same 94machine. --- 10 unchanged lines hidden (view full) --- 105to the OS. 106.Pp 107For this reason, it is recommended that if 108.Nm 109is bridged to a physcal interface, then transmit checksum offloading should be 110disabled on the netfront. 111The Xennet protocol does not have any mechanism for the netback to request 112the netfront to do this; the operator must do it manually. | 107.Sh CAVEATS 108Packets sent through Xennet pass over shared memory, so the protocol includes 109no form of link-layer checksum or CRC. 110Furthermore, Xennet drivers always report to their hosts that they support 111receive and transmit checksum offloading. 112They "offload" the checksum calculation by simply skipping it. 113That works fine for packets that are exchanged between two domains on the same 114machine. --- 10 unchanged lines hidden (view full) --- 125to the OS. 126.Pp 127For this reason, it is recommended that if 128.Nm 129is bridged to a physcal interface, then transmit checksum offloading should be 130disabled on the netfront. 131The Xennet protocol does not have any mechanism for the netback to request 132the netfront to do this; the operator must do it manually. |
| 113.Sh SEE ALSO 114.Xr arp 4 , 115.Xr netintro 4 , 116.Xr ng_ether 4 , 117.Xr xen 4 , 118.Xr ifconfig 8 119.Sh HISTORY 120The 121.Nm 122device driver first appeared in 123.Fx 10.0 . 124.Sh AUTHORS 125The 126.Nm 127driver was written by 128.An Alan Somers 129.Aq alans@spectralogic.com 130and 131.An John Suykerbuyk 132.Aq johns@spectralogic.com | |
| 133.Sh BUGS 134The 135.Nm 136driver does not properly checksum UDP datagrams that span more than one 137Ethernet frame. 138Nor does it correctly checksum IPv6 packets. 139To workaround that bug, disable transmit checksum offloading on the 140netfront driver. | 133.Sh BUGS 134The 135.Nm 136driver does not properly checksum UDP datagrams that span more than one 137Ethernet frame. 138Nor does it correctly checksum IPv6 packets. 139To workaround that bug, disable transmit checksum offloading on the 140netfront driver. |