2 This file is part of systemd.
4 Copyright 2012 Kay Sievers <kay@vrfy.org>
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
21 * Predictable network interface device names based on:
22 * - firmware/bios-provided index numbers for on-board devices
23 * - firmware-provided pci-express hotplug slot index number
24 * - physical/geographical location of the hardware
25 * - the interface's MAC address
27 * http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames
29 * Two character prefixes based on the type of interface:
35 * o<index> -- on-board device index number
36 * s<slot>[f<function>][d<dev_id>] -- hotplug slot index number
37 * x<MAC> -- MAC address
38 * [P<domain>]p<bus>s<slot>[f<function>][d<dev_id>]
39 * -- PCI geographical location
40 * [P<domain>]p<bus>s<slot>[f<function>][u<port>][..][c<config>][i<interface>]
41 * -- USB port number chain
43 * All multi-function PCI devices will carry the [f<function>] number in the
44 * device name, including the function 0 device.
46 * When using PCI geography, The PCI domain is only prepended when it is not 0.
48 * For USB devices the full chain of port numbers of hubs is composed. If the
49 * name gets longer than the maximum number of 15 characters, the name is not
51 * The usual USB configuration == 1 and interface == 0 values are suppressed.
53 * PCI ethernet card with firmware index "1":
54 * ID_NET_NAME_ONBOARD=eno1
55 * ID_NET_NAME_ONBOARD_LABEL=Ethernet Port 1
57 * PCI ethernet card in hotplug slot with firmware index number:
58 * /sys/devices/pci0000:00/0000:00:1c.3/0000:05:00.0/net/ens1
59 * ID_NET_NAME_MAC=enx000000000466
60 * ID_NET_NAME_PATH=enp5s0
61 * ID_NET_NAME_SLOT=ens1
63 * PCI ethernet multi-function card with 2 ports:
64 * /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.0/net/enp2s0f0
65 * ID_NET_NAME_MAC=enx78e7d1ea46da
66 * ID_NET_NAME_PATH=enp2s0f0
67 * /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.1/net/enp2s0f1
68 * ID_NET_NAME_MAC=enx78e7d1ea46dc
69 * ID_NET_NAME_PATH=enp2s0f1
72 * /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlp3s0
73 * ID_NET_NAME_MAC=wlx0024d7e31130
74 * ID_NET_NAME_PATH=wlp3s0
76 * USB built-in 3G modem:
77 * /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.6/net/wwp0s29u1u4i6
78 * ID_NET_NAME_MAC=wwx028037ec0200
79 * ID_NET_NAME_PATH=wwp0s29u1u4i6
82 * /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/net/enp0s29u1u2
83 * ID_NET_NAME_MAC=enxd626b3450fb5
84 * ID_NET_NAME_PATH=enp0s29u1u2
94 #include <linux/pci_regs.h>
107 enum netname_type type;
112 struct udev_device *pcidev;
113 char pci_slot[IFNAMSIZ];
114 char pci_path[IFNAMSIZ];
115 char pci_onboard[IFNAMSIZ];
116 const char *pci_onboard_label;
118 char usb_ports[IFNAMSIZ];
120 char bcma_core[IFNAMSIZ];
123 /* retrieve on-board index number and label from firmware */
124 static int dev_pci_onboard(struct udev_device *dev, struct netnames *names) {
128 /* ACPI _DSM -- device specific method for naming a PCI or PCI Express device */
129 index = udev_device_get_sysattr_value(names->pcidev, "acpi_index");
130 /* SMBIOS type 41 -- Onboard Devices Extended Information */
132 index = udev_device_get_sysattr_value(names->pcidev, "index");
135 idx = strtoul(index, NULL, 0);
138 snprintf(names->pci_onboard, sizeof(names->pci_onboard), "o%d", idx);
140 names->pci_onboard_label = udev_device_get_sysattr_value(names->pcidev, "label");
144 /* read the 256 bytes PCI configuration space to check the multi-function bit */
145 static bool is_pci_multifunction(struct udev_device *dev) {
151 snprintf(filename, sizeof(filename), "%s/config", udev_device_get_syspath(dev));
152 f = fopen(filename, "re");
155 if (fread(&config, sizeof(config), 1, f) != 1)
158 /* bit 0-6 header type, bit 7 multi/single function device */
159 if ((config[PCI_HEADER_TYPE] & 0x80) != 0)
167 static int dev_pci_slot(struct udev_device *dev, struct netnames *names) {
168 struct udev *udev = udev_device_get_udev(names->pcidev);
169 unsigned domain, bus, slot, func, dev_id = 0;
173 struct udev_device *pci = NULL;
174 char slots[256], str[256];
175 _cleanup_closedir_ DIR *dir = NULL;
177 int hotplug_slot = 0, err = 0;
179 if (sscanf(udev_device_get_sysname(names->pcidev), "%x:%x:%x.%u", &domain, &bus, &slot, &func) != 4)
182 /* kernel provided multi-device index */
183 attr = udev_device_get_sysattr_value(dev, "dev_id");
185 dev_id = strtol(attr, NULL, 16);
187 /* compose a name based on the raw kernel's PCI bus, slot numbers */
189 l = sizeof(names->pci_path);
191 l = strpcpyf(&s, l, "P%d", domain);
192 l = strpcpyf(&s, l, "p%ds%d", bus, slot);
193 if (func > 0 || is_pci_multifunction(names->pcidev))
194 l = strpcpyf(&s, l, "f%d", func);
196 l = strpcpyf(&s, l, "d%d", dev_id);
198 names->pci_path[0] = '\0';
200 /* ACPI _SUN -- slot user number */
201 pci = udev_device_new_from_subsystem_sysname(udev, "subsystem", "pci");
206 snprintf(slots, sizeof(slots), "%s/slots", udev_device_get_syspath(pci));
207 dir = opendir(slots);
213 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
218 if (dent->d_name[0] == '.')
220 i = strtol(dent->d_name, &rest, 10);
225 snprintf(str, sizeof(str), "%s/%s/address", slots, dent->d_name);
226 if (read_one_line_file(str, &address) >= 0) {
227 /* match slot address with device by stripping the function */
228 if (strneq(address, udev_device_get_sysname(names->pcidev), strlen(address)))
233 if (hotplug_slot > 0)
237 if (hotplug_slot > 0) {
239 l = sizeof(names->pci_slot);
241 l = strpcpyf(&s, l, "P%d", domain);
242 l = strpcpyf(&s, l, "s%d", hotplug_slot);
243 if (func > 0 || is_pci_multifunction(names->pcidev))
244 l = strpcpyf(&s, l, "f%d", func);
246 l = strpcpyf(&s, l, "d%d", dev_id);
248 names->pci_path[0] = '\0';
251 udev_device_unref(pci);
255 static int names_pci(struct udev_device *dev, struct netnames *names) {
256 struct udev_device *parent;
258 parent = udev_device_get_parent(dev);
261 /* check if our direct parent is a PCI device with no other bus in-between */
262 if (streq_ptr("pci", udev_device_get_subsystem(parent))) {
263 names->type = NET_PCI;
264 names->pcidev = parent;
266 names->pcidev = udev_device_get_parent_with_subsystem_devtype(dev, "pci", NULL);
270 dev_pci_onboard(dev, names);
271 dev_pci_slot(dev, names);
275 static int names_usb(struct udev_device *dev, struct netnames *names) {
276 struct udev_device *usbdev;
284 usbdev = udev_device_get_parent_with_subsystem_devtype(dev, "usb", "usb_interface");
288 /* get USB port number chain, configuration, interface */
289 strscpy(name, sizeof(name), udev_device_get_sysname(usbdev));
290 s = strchr(name, '-');
295 s = strchr(ports, ':');
301 s = strchr(config, '.');
307 /* prefix every port number in the chain with "u"*/
309 while ((s = strchr(s, '.')))
311 s = names->usb_ports;
312 l = strpcpyl(&s, sizeof(names->usb_ports), "u", ports, NULL);
314 /* append USB config number, suppress the common config == 1 */
315 if (!streq(config, "1"))
316 l = strpcpyl(&s, sizeof(names->usb_ports), "c", config, NULL);
318 /* append USB interface number, suppress the interface == 0 */
319 if (!streq(interf, "0"))
320 l = strpcpyl(&s, sizeof(names->usb_ports), "i", interf, NULL);
322 return -ENAMETOOLONG;
324 names->type = NET_USB;
328 static int names_bcma(struct udev_device *dev, struct netnames *names) {
329 struct udev_device *bcmadev;
332 bcmadev = udev_device_get_parent_with_subsystem_devtype(dev, "bcma", NULL);
336 /* bus num:core num */
337 if (sscanf(udev_device_get_sysname(bcmadev), "bcma%*u:%u", &core) != 1)
339 /* suppress the common core == 0 */
341 snprintf(names->bcma_core, sizeof(names->bcma_core), "b%u", core);
343 names->type = NET_BCMA;
347 static int names_mac(struct udev_device *dev, struct netnames *names) {
350 unsigned int a1, a2, a3, a4, a5, a6;
352 /* check for NET_ADDR_PERM, skip random MAC addresses */
353 s = udev_device_get_sysattr_value(dev, "addr_assign_type");
356 i = strtoul(s, NULL, 0);
360 s = udev_device_get_sysattr_value(dev, "address");
363 if (sscanf(s, "%x:%x:%x:%x:%x:%x", &a1, &a2, &a3, &a4, &a5, &a6) != 6)
366 /* skip empty MAC addresses */
367 if (a1 + a2 + a3 + a4 + a5 + a6 == 0)
376 names->mac_valid = true;
380 /* IEEE Organizationally Unique Identifier vendor string */
381 static int ieee_oui(struct udev_device *dev, struct netnames *names, bool test) {
384 if (!names->mac_valid)
386 /* skip commonly misused 00:00:00 (Xerox) prefix */
387 if (memcmp(names->mac, "\0\0\0", 3) == 0)
389 snprintf(str, sizeof(str), "OUI:%02X%02X%02X%02X%02X%02X",
390 names->mac[0], names->mac[1], names->mac[2],
391 names->mac[3], names->mac[4], names->mac[5]);
392 udev_builtin_hwdb_lookup(dev, NULL, str, NULL, test);
396 static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool test) {
401 const char *prefix = "en";
402 struct netnames names = {};
405 /* handle only ARPHRD_ETHER devices */
406 s = udev_device_get_sysattr_value(dev, "type");
409 i = strtoul(s, NULL, 0);
413 /* skip stacked devices, like VLANs, ... */
414 s = udev_device_get_sysattr_value(dev, "ifindex");
417 p = udev_device_get_sysattr_value(dev, "iflink");
423 devtype = udev_device_get_devtype(dev);
425 if (streq("wlan", devtype))
427 else if (streq("wwan", devtype))
431 err = names_mac(dev, &names);
432 if (err >= 0 && names.mac_valid) {
435 snprintf(str, sizeof(str), "%sx%02x%02x%02x%02x%02x%02x", prefix,
436 names.mac[0], names.mac[1], names.mac[2],
437 names.mac[3], names.mac[4], names.mac[5]);
438 udev_builtin_add_property(dev, test, "ID_NET_NAME_MAC", str);
440 ieee_oui(dev, &names, test);
443 /* get PCI based path names, we compose only PCI based paths */
444 err = names_pci(dev, &names);
448 /* plain PCI device */
449 if (names.type == NET_PCI) {
452 if (names.pci_onboard[0])
453 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard) < (int)sizeof(str))
454 udev_builtin_add_property(dev, test, "ID_NET_NAME_ONBOARD", str);
456 if (names.pci_onboard_label)
457 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard_label) < (int)sizeof(str))
458 udev_builtin_add_property(dev, test, "ID_NET_LABEL_ONBOARD", str);
460 if (names.pci_path[0])
461 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_path) < (int)sizeof(str))
462 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
464 if (names.pci_slot[0])
465 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_slot) < (int)sizeof(str))
466 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
471 err = names_usb(dev, &names);
472 if (err >= 0 && names.type == NET_USB) {
475 if (names.pci_path[0])
476 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.usb_ports) < (int)sizeof(str))
477 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
479 if (names.pci_slot[0])
480 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.usb_ports) < (int)sizeof(str))
481 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
486 err = names_bcma(dev, &names);
487 if (err >= 0 && names.type == NET_BCMA) {
490 if (names.pci_path[0])
491 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.bcma_core) < (int)sizeof(str))
492 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
494 if (names.pci_slot[0])
495 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.bcma_core) < (int)sizeof(str))
496 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
504 const struct udev_builtin udev_builtin_net_id = {
506 .cmd = builtin_net_id,
507 .help = "network device properties",