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udev: add network link configuration tool 

This tool applies hardware specific settings to network devices before they
are announced via libudev.

Settings that will probably eventually be supported are MTU, Speed,
DuplexMode, WakeOnLan, MACAddress, MACAddressPolicy (e.g., 'hardware',
'synthetic' or 'random'), Name and NamePolicy (replacing our current
interface naming logic). This patch only introduces support for
Description, as a proof of concept.

Some of these settings may later be overriden by a network management
daemon/script. However, these tools should always listen and wait on libudev
before touching a device (listening on netlink is not enough). This is no
different from how things used to be, as we always supported changing the
network interface name from udev rules, which does not work if someone
has already started using it.

The tool is configured by .link files in /etc/net/links/ (with the usual
overriding logic in /run and /lib). The first (in lexicographical order)
matching .link file is applied to a given device, and all others are ignored.

The .link files contain a [Match] section with (currently) the keys
MACAddress, Driver, Type (see DEVTYPE in udevadm info) and Path (this
matches on the stable device path as exposed as ID_PATH, and not the
unstable DEVPATH). A .link file matches a given device if all of the
specified keys do. Currently the keys are treated as plain strings,
but some limited globbing may later be added to the keys where it
makes sense.

Example:

/etc/net/links/50-wireless.link
[Match]
MACAddress=98:f2:e4:42:c6:92
Path=pci-0000:02:00.0-bcma-0
Type=wlan

[Link]
Description=The wireless link
This commit is contained in:
Tom Gundersen 2013-10-26 00:34:01 +02:00
parent ca5c410573
commit af6f0d422c
11 changed files with 456 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
Makefile.am
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@ -83,6 +83,7 @@ userunitdir=$(prefix)/lib/systemd/user
userpresetdir=$(prefix)/lib/systemd/user-preset
tmpfilesdir=$(prefix)/lib/tmpfiles.d
sysctldir=$(prefix)/lib/sysctl.d
linkdir=$(prefix)/lib/net/links
pkgincludedir=$(includedir)/systemd
systemgeneratordir=$(rootlibexecdir)/system-generators
usergeneratordir=$(prefix)/lib/systemd/user-generators
@ -179,6 +180,7 @@ AM_CPPFLAGS = \
-I $(top_srcdir)/src/core \
-I $(top_srcdir)/src/libudev \
-I $(top_srcdir)/src/udev \
-I $(top_srcdir)/src/udev/net \
-I $(top_builddir)/src/udev \
-I $(top_srcdir)/src/libsystemd-bus \
$(OUR_CPPFLAGS)
@ -2208,6 +2210,7 @@ dist_udevrules_DATA += \
rules/75-tty-description.rules \
rules/78-sound-card.rules \
rules/80-net-name-slot.rules \
rules/85-net-configure-link.rules \
rules/95-udev-late.rules
dist_udevhwdb_DATA = \
@ -2288,19 +2291,27 @@ libudev_core_la_SOURCES = \
src/udev/udev-builtin-input_id.c \
src/udev/udev-builtin-keyboard.c \
src/udev/udev-builtin-net_id.c \
src/udev/udev-builtin-net_link.c \
src/udev/udev-builtin-path_id.c \
src/udev/udev-builtin-usb_id.c
src/udev/udev-builtin-usb_id.c \
src/udev/net/link-config.h \
src/udev/net/link-config.c
nodist_libudev_core_la_SOURCES = \
src/udev/keyboard-keys-from-name.h \
src/udev/keyboard-keys-to-name.h
src/udev/keyboard-keys-to-name.h \
src/udev/net/link-config-gperf.c
BUILT_SOURCES += \
$(nodist_libudev_core_la_SOURCES)
CLEANFILES += \
src/udev/keyboard-keys-from-name.gperf \
src/udev/keyboard-keys.txt
src/udev/keyboard-keys.txt \
src/udev/net/link-config-gperf.c
EXTRA_DIST += \
src/udev/net/link-config-gperf.gperf
libudev_core_la_CFLAGS = \
$(AM_CFLAGS) \
@ -4456,6 +4467,8 @@ endif
INSTALL_DIRS += \
$(prefix)/lib/modules-load.d \
$(sysconfdir)/modules-load.d \
$(prefix)/lib/net/links \
$(sysconfdir)/net/links \
$(prefix)/lib/sysctl.d \
$(sysconfdir)/sysctl.d \
$(prefix)/lib/kernel/install.d \

8
TODO
View File

@ -714,6 +714,14 @@ Features:
* systemd-run is missing zsh completion scripts
* udev-link-config:
- Make sure ID_PATH is always exported and complete for
network devices where possible, so we can safely rely
on Path= matching
- NamePolicy= replace the current naming rules
- MACPolicy= support 'firmware', 'synthetic' and 'random'
- Check if Driver= is broken, or just my driver (bcma)
External:
* dbus:

11
rules/85-net-configure-link.rules Normal file
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@ -0,0 +1,11 @@
# do not edit this file, it will be overwritten on update
SUBSYSTEM!="net", GOTO="net_link_end"
IMPORT{builtin}="path_id"
ACTION!="add", GOTO="net_link_end"
RUN{builtin}="net_link"
LABEL="net_link_end"

1
src/udev/net/.gitignore vendored Normal file
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@ -0,0 +1 @@
/link-config-gperf.c

1
src/udev/net/Makefile Symbolic link
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@ -0,0 +1 @@
../../Makefile

21
src/udev/net/link-config-gperf.gperf Normal file
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@ -0,0 +1,21 @@
%{
#include <stddef.h>
#include "conf-parser.h"
#include "link-config.h"
%}
struct ConfigPerfItem;
%null_strings
%language=ANSI-C
%define slot-name section_and_lvalue
%define hash-function-name link_config_gperf_hash
%define lookup-function-name link_config_gperf_lookup
%readonly-tables
%omit-struct-type
%struct-type
%includes
%%
Match.MACAddress, config_parse_string, 0, offsetof(link_config, match_mac)
Match.Path, config_parse_string, 0, offsetof(link_config, match_path)
Match.Driver, config_parse_string, 0, offsetof(link_config, match_driver)
Match.Type, config_parse_string, 0, offsetof(link_config, match_type)
Link.Description, config_parse_string, 0, offsetof(link_config, description)

244
src/udev/net/link-config.c Normal file
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@ -0,0 +1,244 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright (C) 2013 Tom Gundersen <teg@jklm.no>
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include "link-config.h"
#include "util.h"
#include "log.h"
#include "strv.h"
#include "path-util.h"
#include "conf-parser.h"
#include "conf-files.h"
struct link_config_ctx {
LIST_HEAD(link_config, links);
char **link_dirs;
usec_t *link_dirs_ts_usec;
};
int link_config_ctx_new(link_config_ctx **ret) {
link_config_ctx *ctx;
if (!ret)
return -EINVAL;
ctx = new0(link_config_ctx, 1);
if (!ctx)
return -ENOMEM;
LIST_HEAD_INIT(ctx->links);
ctx->link_dirs = strv_new("/etc/net/links",
"/run/net/links",
"/usr/lib/net/links",
NULL);
if (!ctx->link_dirs) {
log_error("failed to build link config directory array");
link_config_ctx_free(ctx);
return -ENOMEM;
}
if (!path_strv_canonicalize_uniq(ctx->link_dirs)) {
log_error("failed to canonicalize link config directories\n");
link_config_ctx_free(ctx);
return -ENOMEM;
}
ctx->link_dirs_ts_usec = calloc(strv_length(ctx->link_dirs), sizeof(usec_t));
if(!ctx->link_dirs_ts_usec) {
link_config_ctx_free(ctx);
return -ENOMEM;
}
*ret = ctx;
return 0;
}
static void link_configs_free(link_config_ctx *ctx) {
link_config *link, *link_next;
if (!ctx)
return;
LIST_FOREACH_SAFE(links, link, link_next, ctx->links) {
free(link->filename);
free(link->match_path);
free(link->match_driver);
free(link->match_type);
free(link->description);
free(link);
}
}
void link_config_ctx_free(link_config_ctx *ctx) {
if (!ctx)
return;
strv_free(ctx->link_dirs);
free(ctx->link_dirs_ts_usec);
link_configs_free(ctx);
free(ctx);
return;
}
static int load_link(link_config_ctx *ctx, const char *filename) {
link_config *link;
FILE *file;
int r;
file = fopen(filename, "re");
if (!file) {
if (errno == ENOENT)
return 0;
else
return errno;
}
link = new0(link_config, 1);
if (!link) {
r = log_oom();
goto failure;
}
r = config_parse(NULL, filename, file, "Match\0Link\0Ethernet\0", config_item_perf_lookup,
(void*) link_config_gperf_lookup, false, false, link);
if (r < 0) {
log_warning("Colud not parse config file %s: %s", filename, strerror(-r));
goto failure;
} else
log_info("Parsed configuration file %s", filename);
link->filename = strdup(filename);
LIST_PREPEND(links, ctx->links, link);
return 0;
failure:
free(link);
return r;
}
int link_config_load(link_config_ctx *ctx) {
int r;
char **files, **f;
link_configs_free(ctx);
/* update timestamps */
paths_check_timestamp(ctx->link_dirs, ctx->link_dirs_ts_usec, true);
r = conf_files_list_strv(&files, ".link", NULL, (const char **)ctx->link_dirs);
if (r < 0) {
log_error("failed to enumerate link files: %s", strerror(-r));
return r;
}
STRV_FOREACH_BACKWARDS(f, files) {
r = load_link(ctx, *f);
if (r < 0)
return r;
}
return 0;
}
bool link_config_should_reload(link_config_ctx *ctx) {
return paths_check_timestamp(ctx->link_dirs, ctx->link_dirs_ts_usec, false);
}
static bool match_config(link_config *match, struct udev_device *device) {
const char *property;
if (match->match_mac) {
property = udev_device_get_sysattr_value(device, "address");
if (!property || !streq(match->match_mac, property)) {
log_debug("Device MAC address (%s) did not match MACAddress=%s", property, match->match_mac);
return 0;
}
}
if (match->match_path) {
property = udev_device_get_property_value(device, "ID_PATH");
if (!property || !streq(match->match_path, property)) {
log_debug("Device's persistent path (%s) did not match Path=%s", property, match->match_path);
return 0;
}
}
if (match->match_driver) {
property = udev_device_get_driver(device);
if (!property || !streq(match->match_driver, property)) {
log_debug("Device driver (%s) did not match Driver=%s", property, match->match_driver);
return 0;
}
}
if (match->match_type) {
property = udev_device_get_devtype(device);
if (!property || !streq(match->match_type, property)) {
log_debug("Device type (%s) did not match Type=%s", property, match->match_type);
return 0;
}
}
return 1;
}
int link_config_get(link_config_ctx *ctx, struct udev_device *device, link_config **ret) {
link_config *link;
LIST_FOREACH(links, link, ctx->links) {
if (!match_config(link, device)) {
log_info("Config file %s does not apply to device %s", link->filename, udev_device_get_sysname(device));
} else {
log_info("Config file %s applies to device %s", link->filename, udev_device_get_sysname(device));
*ret = link;
return 0;
}
}
return -ENOENT;
}
int link_config_apply(link_config_ctx *ctx, link_config *config, struct udev_device *device) {
const char *name;
int r;
name = udev_device_get_sysname(device);
if (!name)
return -EINVAL;
log_info("Configuring %s", name);
if (config->description) {
r = udev_device_set_sysattr_value(device, "ifalias", config->description);
if (r < 0)
log_warning("Could not set description of %s to '%s': %s", name, config->description, strerror(-r));
else
log_info("Set link description of %s to '%s'", name, config->description);
}
return 0;
}

55
src/udev/net/link-config.h Normal file
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@ -0,0 +1,55 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright (C) 2013 Tom Gundersen <teg@jklm.no>
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#pragma once
#include "libudev.h"
#include "util.h"
#include "list.h"
typedef struct link_config_ctx link_config_ctx;
typedef struct link_config link_config;
struct link_config {
char *filename;
char *match_mac;
char *match_path;
char *match_driver;
char *match_type;
char *description;
LIST_FIELDS(link_config, links);
};
int link_config_ctx_new(link_config_ctx **ret);
void link_config_ctx_free(link_config_ctx *ctx);
int link_config_load(link_config_ctx *ctx);
bool link_config_should_reload(link_config_ctx *ctx);
int link_config_get(link_config_ctx *ctx, struct udev_device *device, struct link_config **ret);
int link_config_apply(link_config_ctx *ctx, struct link_config *config, struct udev_device *device);
/* gperf lookup function */
const struct ConfigPerfItem* link_config_gperf_lookup(const char *key, unsigned length);

96
src/udev/udev-builtin-net_link.c Normal file
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@ -0,0 +1,96 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 Tom Gundersen
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include "link-config.h"
#include "udev.h"
#include "log.h"
link_config_ctx *ctx;
static int builtin_net_link(struct udev_device *dev, int argc, char **argv, bool test) {
link_config *link;
int r;
if (argc > 1) {
log_error("This program takes no arguments.");
return EXIT_FAILURE;
}
r = link_config_get(ctx, dev, &link);
if (r < 0) {
if (r == -ENOENT) {
log_info("No matching link configuration found");
return EXIT_SUCCESS;
} else {
log_error("Could not get link config");
return EXIT_FAILURE;
}
}
r = link_config_apply(ctx, link, dev);
if (r < 0) {
log_error("Could not apply link config");
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
static int builtin_net_link_init(struct udev *udev) {
int r;
if (ctx)
return 0;
r = link_config_ctx_new(&ctx);
if (r < 0)
return r;
r = link_config_load(ctx);
if (r < 0)
return r;
log_debug("Created link configuration context");
return 0;
}
static void builtin_net_link_exit(struct udev *udev) {
link_config_ctx_free(ctx);
log_debug("Unloaded link configuration context");
}
static bool builtin_net_link_validate(struct udev *udev) {
log_debug("Check if link configuration needs reloading");
if (!ctx)
return false;
return link_config_should_reload(ctx);
}
const struct udev_builtin udev_builtin_net_link = {
.name = "net_link",
.cmd = builtin_net_link,
.init = builtin_net_link_init,
.exit = builtin_net_link_exit,
.validate = builtin_net_link_validate,
.help = "configure network link",
.run_once = false,
};

1
src/udev/udev-builtin.c
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@ -44,6 +44,7 @@ static const struct udev_builtin *builtins[] = {
[UDEV_BUILTIN_KMOD] = &udev_builtin_kmod,
#endif
[UDEV_BUILTIN_NET_ID] = &udev_builtin_net_id,
[UDEV_BUILTIN_NET_LINK] = &udev_builtin_net_link,
[UDEV_BUILTIN_PATH_ID] = &udev_builtin_path_id,
[UDEV_BUILTIN_USB_ID] = &udev_builtin_usb_id,
#ifdef HAVE_ACL

2
src/udev/udev.h
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@ -153,6 +153,7 @@ enum udev_builtin_cmd {
UDEV_BUILTIN_KMOD,
#endif
UDEV_BUILTIN_NET_ID,
UDEV_BUILTIN_NET_LINK,
UDEV_BUILTIN_PATH_ID,
UDEV_BUILTIN_USB_ID,
#ifdef HAVE_ACL
@ -183,6 +184,7 @@ extern const struct udev_builtin udev_builtin_keyboard;
extern const struct udev_builtin udev_builtin_kmod;
#endif
extern const struct udev_builtin udev_builtin_net_id;
extern const struct udev_builtin udev_builtin_net_link;
extern const struct udev_builtin udev_builtin_path_id;
extern const struct udev_builtin udev_builtin_usb_id;
extern const struct udev_builtin udev_builtin_uaccess;