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Systemd/src/udev/udev-builtin-net_id.c

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/***
This file is part of systemd.
Copyright 2012 Kay Sievers <kay@vrfy.org>
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/>.
***/
/*
* predictable network interface device names based on:
* - firmware/bios-provided index numbers for on-board devices
* - firmware-provided pci-express hotplug slot index number
* - physical/geographical location of the hardware
* - the interface's MAC address
*
* two character prefixes based on the type of interface:
* en -- ethernet
* wl -- wlan
* ww -- wwan
*
* type of names:
* o<index> -- on-board device index number
* s<slot>[f<function>] -- hotplug slot index number
* x<MAC> -- MAC address
* p<bus>s<slot>[f<function>] -- PCI geographical location
*
* All multi-function devices will carry the [f<function>] number in the
* device name, including the function 0 device.
*
* examples:
* ID_NET_NAME_ONBOARD=eno1
* ID_NET_NAME_SLOT=ens1
* ID_NET_NAME_SLOT=ens2f0
* ID_NET_NAME_SLOT=ens2f1
* ID_NET_NAME_MAC=enxf0def180d479
* ID_NET_NAME_PATH=enp0s25
* ID_NET_NAME_PATH=enp19s3f0
* ID_NET_NAME_PATH=enp19s3f1
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <linux/pci_regs.h>
#include "udev.h"
/* retrieve on-board index number and label from firmware */
static int dev_pci_onboard(struct udev_device *dev, struct udev_device *parent, const char *prefix, bool test) {
const char *index;
int idx;
const char *label;
char s[16];
int err;
/* ACPI _DSM -- device specific method for naming a PCI or PCI Express device */
index = udev_device_get_sysattr_value(parent, "acpi_index");
/* SMBIOS type 41 -- Onboard Devices Extended Information */
if (!index)
index = udev_device_get_sysattr_value(parent, "index");
if (!index)
return -ENOENT;
idx = strtoul(index, NULL, 0);
if (idx <= 0)
return -EINVAL;
snprintf(s, sizeof(s), "%so%d", prefix, idx);
err = udev_builtin_add_property(dev, test, "ID_NET_NAME_ONBOARD", s);
if (err < 0)
return err;
label = udev_device_get_sysattr_value(parent, "label");
if (label) {
err = udev_builtin_add_property(dev, test, "ID_NET_LABEL_ONBOARD", label);
if (err < 0)
return err;
}
return 0;
}
/* read the 256 bytes PCI configuration space to check the multi-function bit */
static bool is_pci_singlefunction(struct udev_device *dev) {
char filename[256];
FILE *f;
char config[256];
bool single = false;
snprintf(filename, sizeof(filename), "%s/config", udev_device_get_syspath(dev));
f = fopen(filename, "re");
if (!f)
goto out;
if (fread(&config, sizeof(config), 1, f) != 1)
goto out;
/* bit 0-6 header type, bit 7 multi/single function device */
if ((config[PCI_HEADER_TYPE] & 0x80) == 0)
single = true;
out:
fclose(f);
return single;
}
static int dev_pci_slot(struct udev_device *dev, struct udev_device *parent, const char *prefix, bool test) {
struct udev *udev = udev_device_get_udev(dev);
unsigned int bus;
unsigned int slot;
unsigned int func;
struct udev_device *pci = NULL;
char slots[256];
DIR *dir;
struct dirent *dent;
char str[256];
int hotplug_slot = 0;
int err = 0;
/* compose a name based on the raw kernel's PCI bus, slot numbers */
if (sscanf(udev_device_get_sysname(parent), "0000:%x:%x.%d", &bus, &slot, &func) != 3)
return -ENOENT;
if (func == 0 && is_pci_singlefunction(parent))
snprintf(str, sizeof(str), "%sp%ds%d", prefix, bus, slot);
else
snprintf(str, sizeof(str), "%sp%ds%df%d", prefix, bus, slot, func);
err = udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
if (err < 0)
return err;
/* ACPI _SUN -- slot user number */
pci = udev_device_new_from_subsystem_sysname(udev, "subsystem", "pci");
if (!pci) {
err = -ENOENT;
goto out;
}
snprintf(slots, sizeof(slots), "%s/slots", udev_device_get_syspath(pci));
dir = opendir(slots);
if (!dir) {
err = -errno;
goto out;
}
for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
int i;
char *rest;
char *address;
if (dent->d_name[0] == '.')
continue;
i = strtol(dent->d_name, &rest, 10);
if (rest[0] != '\0')
continue;
if (i < 1)
continue;
snprintf(str, sizeof(str), "%s/%s/address", slots, dent->d_name);
if (read_one_line_file(str, &address) >= 0) {
/* match slot address with device by stripping the function */
if (strncmp(address, udev_device_get_sysname(parent), strlen(address)) == 0)
hotplug_slot = i;
free(address);
}
if (hotplug_slot > 0)
break;
}
closedir(dir);
if (hotplug_slot > 0) {
if (func == 0 && is_pci_singlefunction(parent))
snprintf(str, sizeof(str), "%ss%d", prefix, hotplug_slot);
else
snprintf(str, sizeof(str), "%ss%df%d", prefix, hotplug_slot, func);
err = udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
}
out:
udev_device_unref(pci);
return err;
}
static int dev_pci(struct udev_device *dev, const char *prefix, bool test) {
struct udev_device *parent;
/* skip other buses than direct PCI parents */
parent = udev_device_get_parent(dev);
if (!parent || !streq("pci", udev_device_get_subsystem(parent)))
return -ENOENT;
dev_pci_onboard(dev, parent, prefix, test);
dev_pci_slot(dev, parent, prefix, test);
return 0;
}
static int dev_mac(struct udev_device *dev, const char *prefix, bool test) {
const char *s;
unsigned int i;
unsigned int a1, a2, a3, a4, a5, a6;
char str[16];
/* check for NET_ADDR_PERM, skip random MAC addresses */
s = udev_device_get_sysattr_value(dev, "addr_assign_type");
if (!s)
return EXIT_FAILURE;
i = strtoul(s, NULL, 0);
if (i != 0)
return 0;
s = udev_device_get_sysattr_value(dev, "address");
if (!s)
return -ENOENT;
if (sscanf(s, "%x:%x:%x:%x:%x:%x", &a1, &a2, &a3, &a4, &a5, &a6) != 6)
return -EINVAL;
/* skip empty MAC addresses */
if (a1 + a2 + a3 + a4 + a5 + a6 == 0)
return -EINVAL;
/*
* IEEE Organizationally Unique Identifier vendor string
* skip commonly misused 00:00:00 (Xerox) prefix
*/
if (a1 + a2 + a3 > 0) {
snprintf(str, sizeof(str), "OUI:%02X%02X%02X", a1, a2, a3);
udev_builtin_hwdb_lookup(dev, str, test);
}
snprintf(str, sizeof(str), "%sx%02x%02x%02x%02x%02x%02x", prefix, a1, a2, a3, a4, a5, a6);
return udev_builtin_add_property(dev, test, "ID_NET_NAME_MAC", str);
}
static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool test) {
const char *s;
unsigned int i;
const char *devtype;
const char *prefix = "en";
/* handle only ARPHRD_ETHER devices */
s = udev_device_get_sysattr_value(dev, "type");
if (!s)
return EXIT_FAILURE;
i = strtoul(s, NULL, 0);
if (i != 1)
return 0;
devtype = udev_device_get_devtype(dev);
if (devtype) {
if (streq("wlan", devtype))
prefix = "wl";
else if (streq("wwan", devtype))
prefix = "ww";
}
dev_pci(dev, prefix, test);
dev_mac(dev, prefix, test);
return EXIT_SUCCESS;
}
const struct udev_builtin udev_builtin_net_id = {
.name = "net_id",
.cmd = builtin_net_id,
.help = "network device properties",
};
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