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Support vlan_group workaround implemented in XenServer kernels.
Some Linux network drivers support a feature called "VLAN acceleration",
associated with a data structure called a "vlan_group". A vlan_group is,
abstractly, a dictionary that maps from a VLAN ID (in the range 0...4095)
to a VLAN device, that is, a Linux network device associated with a
particular VLAN, e.g. "eth0.9" for VLAN 9 on eth0.
Some drivers that support VLAN acceleration have bugs that fall roughly
into the following categories:
* Some NICs strip VLAN tags on receive if no vlan_group is registered,
so that the tag is completely lost.
* Some drivers size their receive buffers based on whether a vlan_group
is enabled, meaning that a maximum size packet with a VLAN tag will
not fit if a vlan_group is not configured.
* On transmit some drivers expect that VLAN acceleration will be used
if it is available (which can only be done if a vlan_group is
configured). In these cases, the driver may fail to parse the packet
and correctly setup checksum offloading and/or TSO.
The correct long term solution is to fix these driver bugs. To cope until
then, we have prepared a patch to the Linux kernel network stack that works
around these problems. This commit adds support for the workaround
implemented by that patch.
Signed-off-by: Ben Pfaff <[email protected]>
Acked-by: Jesse Gross <[email protected]>- Loading branch information
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,90 @@ | ||
| .\" -*- nroff -*- | ||
| .de IQ | ||
| . br | ||
| . ns | ||
| . IP "\\$1" | ||
| .. | ||
| .TH ovs\-vlan\-bug\-workaround 8 "February 2011" "Open vSwitch" "Open vSwitch Manual" | ||
| .ds PN ovs\-vlan\-bug\-workaround | ||
| . | ||
| .SH NAME | ||
| ovs\-vlan\-bug\-workaround \- utility for configuring Linux VLAN driver bug workaround | ||
| . | ||
| .SH SYNOPSIS | ||
| \fBovs\-vlan\-bug\-workaround \fInetdev\fR \fBon\fR | ||
| .br | ||
| \fBovs\-vlan\-bug\-workaround \fInetdev\fR \fBoff\fR | ||
| .br | ||
| \fBovs\-vlan\-bug\-workaround \-\-help | ||
| .br | ||
| \fBovs\-vlan\-bug\-workaround \-\-version | ||
| .SH DESCRIPTION | ||
| . | ||
| .PP | ||
| Some Linux network drivers support a feature called ``VLAN | ||
| acceleration''. VLAN acceleration is associated with a data structure | ||
| called a \fBvlan_group\fR that is, abstractly, a dictionary that maps | ||
| from a VLAN ID (in the range 0 to 4095) to a VLAN device, that is, a | ||
| Linux network device associated with a particular VLAN, | ||
| e.g. \fBeth0.9\fR for VLAN 9 on \fBeth0\fR. | ||
| .PP | ||
| Some drivers that support VLAN acceleration have bugs that fall | ||
| roughly into the categories listed below. \fBovs\-vlan\-test\fR(8) | ||
| can test for these driver bugs. | ||
| .so utilities/ovs-vlan-bugs.man | ||
| .PP | ||
| .PP | ||
| The correct long term solution is to fix these driver bugs. | ||
| .PP | ||
| For now, \fBovs\-vlan\-bug\-workaround\fR can enable a special-purpose | ||
| workaround for devices with buggy VLAN acceleration. A kernel patch | ||
| must be applied for this workaround to work. | ||
| .PP | ||
| Use the command \fBovs\-vlan\-bug\-workaround \fInetdev\fR \fBon\fR to | ||
| enable the VLAN driver bug workaround for network device \fInetdev\fR. | ||
| Use the command \fBovs\-vlan\-bug\-workaround \fInetdev\fR \fBoff\fR to | ||
| disable the VLAN driver bug workaround for network device \fInetdev\fR. | ||
| .SH "DRIVER DETAILS" | ||
| .PP | ||
| The following drivers in Linux version | ||
| 2.6.32.12-0.7.1.xs1.0.0.311.170586 implement VLAN acceleration and are | ||
| relevant to Open vSwitch on XenServer. We have not tested any version | ||
| of most of these drivers, so we do not know whether they have a VLAN | ||
| problem that needs to be fixed. The drivers are listed by the name | ||
| that they report in, e.g., \fBethtool \-i\fR output; in a few cases | ||
| this differs slightly from the name of the module's \fB.ko\fR file: | ||
| . | ||
| .nf | ||
| .ta T 1i | ||
| \fB8139cp acenic amd8111e atl1c ATL1E atl1 | ||
| atl2 be2net bna bnx2 bnx2x cnic | ||
| cxgb cxgb3 e1000 e1000e enic forcedeth | ||
| igb igbvf ixgb ixgbe jme ml4x_core | ||
| ns83820 qlge r8169 S2IO sky2 starfire | ||
| tehuti tg3 typhoon via-velocity vxge | ||
| .fi | ||
| .PP | ||
| The following drivers use \fBvlan_group\fR but are irrelevant to Open | ||
| vSwitch on XenServer: | ||
| .IP "\fBbonding\fR" | ||
| Not used with Open vSwitch on XenServer. | ||
| .IP "\fBgianfar\fR" | ||
| Not shipped with XenServer. A FreeScale CPU-integrated device. | ||
| .IP "\fBehea\fR" | ||
| Cannot be built on x86. IBM Power architecture only. | ||
| .IP "\fBstmmac\fR" | ||
| Cannot be built on x86. SH4 architecture only. | ||
| .IP "\fBvmxnet3\fR" | ||
| Not shipped with XenServer. For use inside VMware VMs only. | ||
| . | ||
| .SH OPTIONS | ||
| . | ||
| .so lib/common.man | ||
| . | ||
| .SH BUGS | ||
| . | ||
| Obviously. | ||
| . | ||
| .SH "SEE ALSO" | ||
| . | ||
| .BR ovs\-vlan\-test (8). |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,144 @@ | ||
| /* | ||
| * Copyright (c) 2011 Nicira Networks. | ||
| * | ||
| * Licensed under the Apache License, Version 2.0 (the "License"); | ||
| * you may not use this file except in compliance with the License. | ||
| * You may obtain a copy of the License at: | ||
| * | ||
| * http://www.apache.org/licenses/LICENSE-2.0 | ||
| * | ||
| * Unless required by applicable law or agreed to in writing, software | ||
| * distributed under the License is distributed on an "AS IS" BASIS, | ||
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| * See the License for the specific language governing permissions and | ||
| * limitations under the License. | ||
| */ | ||
|
|
||
| #include <config.h> | ||
|
|
||
| #include <errno.h> | ||
| #include <getopt.h> | ||
| #include <linux/if_vlan.h> | ||
| #include <linux/sockios.h> | ||
| #include <net/if.h> | ||
| #include <stdlib.h> | ||
| #include <sys/ioctl.h> | ||
| #include <stdio.h> | ||
| #include <string.h> | ||
| #include <unistd.h> | ||
|
|
||
| #include "command-line.h" | ||
| #include "util.h" | ||
|
|
||
| #define ADD_ALL_VLANS_CMD 10 | ||
| #define DEL_ALL_VLANS_CMD 11 | ||
|
|
||
| static void usage(void); | ||
| static void parse_options(int argc, char *argv[]); | ||
|
|
||
| int | ||
| main(int argc, char *argv[]) | ||
| { | ||
| struct vlan_ioctl_args vlan_args; | ||
| const char *netdev, *setting; | ||
| int fd; | ||
|
|
||
| set_program_name(argv[0]); | ||
|
|
||
| parse_options(argc, argv); | ||
| if (argc - optind != 2) { | ||
| ovs_fatal(0, "exactly two non-option arguments are required " | ||
| "(use --help for help)"); | ||
| } | ||
|
|
||
| memset(&vlan_args, 0, sizeof vlan_args); | ||
|
|
||
| /* Get command. */ | ||
| setting = argv[optind + 1]; | ||
| if (!strcmp(setting, "on")) { | ||
| vlan_args.cmd = ADD_ALL_VLANS_CMD; | ||
| } else if (!strcmp(setting, "off")) { | ||
| vlan_args.cmd = DEL_ALL_VLANS_CMD; | ||
| } else { | ||
| ovs_fatal(0, "second command line argument must be \"on\" or \"off\" " | ||
| "(not \"%s\")", setting); | ||
| } | ||
|
|
||
| /* Get network device name. */ | ||
| netdev = argv[optind]; | ||
| if (strlen(netdev) >= IFNAMSIZ) { | ||
| ovs_fatal(0, "%s: network device name too long", netdev); | ||
| } | ||
| strcpy(vlan_args.device1, netdev); | ||
|
|
||
| /* Execute operation. */ | ||
| fd = socket(AF_INET, SOCK_STREAM, 0); | ||
| if (fd < 0) { | ||
| ovs_fatal(errno, "socket creation failed"); | ||
| } | ||
| if (ioctl(fd, SIOCSIFVLAN, &vlan_args) < 0) { | ||
| if (errno == ENOPKG) { | ||
| ovs_fatal(0, "operation failed (8021q module not loaded)"); | ||
| } else if (errno == EOPNOTSUPP) { | ||
| ovs_fatal(0, "operation failed (kernel does not support the " | ||
| "VLAN bug workaround)"); | ||
| } else { | ||
| ovs_fatal(errno, "operation failed"); | ||
| } | ||
| } | ||
| close(fd); | ||
|
|
||
| return 0; | ||
| } | ||
|
|
||
| static void | ||
| usage(void) | ||
| { | ||
| printf("\ | ||
| %s, for enabling or disabling the kernel VLAN bug workaround\n\ | ||
| usage: %s NETDEV SETTING\n\ | ||
| where NETDEV is a network device (e.g. \"eth0\")\n\ | ||
| and SETTING is \"on\" to enable the workaround or \"off\" to disable it.\n\ | ||
| \n\ | ||
| Options:\n\ | ||
| -h, --help Print this helpful information\n\ | ||
| -V, --version Display version information\n", | ||
| program_name, program_name); | ||
| exit(EXIT_SUCCESS); | ||
| } | ||
|
|
||
| static void | ||
| parse_options(int argc, char *argv[]) | ||
| { | ||
| static const struct option long_options[] = { | ||
| {"help", no_argument, NULL, 'h'}, | ||
| {"version", no_argument, NULL, 'V'}, | ||
| {0, 0, 0, 0}, | ||
| }; | ||
| char *short_options = long_options_to_short_options(long_options); | ||
|
|
||
| for (;;) { | ||
| int option; | ||
|
|
||
| option = getopt_long(argc, argv, "+t:hVe", long_options, NULL); | ||
| if (option == -1) { | ||
| break; | ||
| } | ||
| switch (option) { | ||
| case 'h': | ||
| usage(); | ||
| break; | ||
|
|
||
| case 'V': | ||
| OVS_PRINT_VERSION(0, 0); | ||
| exit(EXIT_SUCCESS); | ||
|
|
||
| case '?': | ||
| exit(EXIT_FAILURE); | ||
|
|
||
| default: | ||
| NOT_REACHED(); | ||
| } | ||
| } | ||
| free(short_options); | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,17 @@ | ||
| .IP \(bu | ||
| When NICs use VLAN stripping on receive they must pass a pointer to a | ||
| \fBvlan_group\fR when reporting the stripped tag to the networking | ||
| core. If no \fBvlan_group\fR is in use then some drivers just drop | ||
| the extracted tag. Drivers are supposed to only enable stripping if a | ||
| \fBvlan_group\fR is registered but not all of them do that. | ||
| . | ||
| .IP \(bu | ||
| Some drivers size their receive buffers based on whether a | ||
| \fBvlan_group\fR is enabled, meaning that a maximum size packet with a | ||
| VLAN tag will not fit if no \fBvlan_group\fR is configured. | ||
| . | ||
| .IP \(bu | ||
| On transmit, some drivers expect that VLAN acceleration will be used | ||
| if it is available, which can only be done if a \fBvlan_group\fR is | ||
| configured. In these cases, the driver may fail to parse the packet | ||
| and correctly setup checksum offloading or TSO. |
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