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:
31 * sl -- serial line IP (slip)
36 * o<index> -- on-board device index number
37 * s<slot>[f<function>][d<dev_id>] -- hotplug slot index number
38 * x<MAC> -- MAC address
39 * [P<domain>]p<bus>s<slot>[f<function>][d<dev_id>]
40 * -- PCI geographical location
41 * [P<domain>]p<bus>s<slot>[f<function>][u<port>][..][c<config>][i<interface>]
42 * -- USB port number chain
44 * All multi-function PCI devices will carry the [f<function>] number in the
45 * device name, including the function 0 device.
47 * When using PCI geography, The PCI domain is only prepended when it is not 0.
49 * For USB devices the full chain of port numbers of hubs is composed. If the
50 * name gets longer than the maximum number of 15 characters, the name is not
52 * The usual USB configuration == 1 and interface == 0 values are suppressed.
54 * PCI ethernet card with firmware index "1":
55 * ID_NET_NAME_ONBOARD=eno1
56 * ID_NET_NAME_ONBOARD_LABEL=Ethernet Port 1
58 * PCI ethernet card in hotplug slot with firmware index number:
59 * /sys/devices/pci0000:00/0000:00:1c.3/0000:05:00.0/net/ens1
60 * ID_NET_NAME_MAC=enx000000000466
61 * ID_NET_NAME_PATH=enp5s0
62 * ID_NET_NAME_SLOT=ens1
64 * PCI ethernet multi-function card with 2 ports:
65 * /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.0/net/enp2s0f0
66 * ID_NET_NAME_MAC=enx78e7d1ea46da
67 * ID_NET_NAME_PATH=enp2s0f0
68 * /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.1/net/enp2s0f1
69 * ID_NET_NAME_MAC=enx78e7d1ea46dc
70 * ID_NET_NAME_PATH=enp2s0f1
73 * /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlp3s0
74 * ID_NET_NAME_MAC=wlx0024d7e31130
75 * ID_NET_NAME_PATH=wlp3s0
77 * USB built-in 3G modem:
78 * /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.6/net/wwp0s29u1u4i6
79 * ID_NET_NAME_MAC=wwx028037ec0200
80 * ID_NET_NAME_PATH=wwp0s29u1u4i6
83 * /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/net/enp0s29u1u2
84 * ID_NET_NAME_MAC=enxd626b3450fb5
85 * ID_NET_NAME_PATH=enp0s29u1u2
95 #include <linux/pci_regs.h>
110 enum netname_type type;
115 struct udev_device *pcidev;
116 char pci_slot[IFNAMSIZ];
117 char pci_path[IFNAMSIZ];
118 char pci_onboard[IFNAMSIZ];
119 const char *pci_onboard_label;
121 char usb_ports[IFNAMSIZ];
123 char bcma_core[IFNAMSIZ];
125 char virtio_core[IFNAMSIZ];
127 char ccw_core[IFNAMSIZ];
130 /* retrieve on-board index number and label from firmware */
131 static int dev_pci_onboard(struct udev_device *dev, struct netnames *names) {
135 /* ACPI _DSM -- device specific method for naming a PCI or PCI Express device */
136 index = udev_device_get_sysattr_value(names->pcidev, "acpi_index");
137 /* SMBIOS type 41 -- Onboard Devices Extended Information */
139 index = udev_device_get_sysattr_value(names->pcidev, "index");
142 idx = strtoul(index, NULL, 0);
145 snprintf(names->pci_onboard, sizeof(names->pci_onboard), "o%d", idx);
147 names->pci_onboard_label = udev_device_get_sysattr_value(names->pcidev, "label");
151 /* read the 256 bytes PCI configuration space to check the multi-function bit */
152 static bool is_pci_multifunction(struct udev_device *dev) {
158 snprintf(filename, sizeof(filename), "%s/config", udev_device_get_syspath(dev));
159 f = fopen(filename, "re");
162 if (fread(&config, sizeof(config), 1, f) != 1)
165 /* bit 0-6 header type, bit 7 multi/single function device */
166 if ((config[PCI_HEADER_TYPE] & 0x80) != 0)
174 static int dev_pci_slot(struct udev_device *dev, struct netnames *names) {
175 struct udev *udev = udev_device_get_udev(names->pcidev);
176 unsigned domain, bus, slot, func, dev_id = 0;
180 struct udev_device *pci = NULL;
181 char slots[256], str[256];
182 _cleanup_closedir_ DIR *dir = NULL;
184 int hotplug_slot = 0, err = 0;
186 if (sscanf(udev_device_get_sysname(names->pcidev), "%x:%x:%x.%u", &domain, &bus, &slot, &func) != 4)
189 /* kernel provided multi-device index */
190 attr = udev_device_get_sysattr_value(dev, "dev_id");
192 dev_id = strtol(attr, NULL, 16);
194 /* compose a name based on the raw kernel's PCI bus, slot numbers */
196 l = sizeof(names->pci_path);
198 l = strpcpyf(&s, l, "P%d", domain);
199 l = strpcpyf(&s, l, "p%ds%d", bus, slot);
200 if (func > 0 || is_pci_multifunction(names->pcidev))
201 l = strpcpyf(&s, l, "f%d", func);
203 l = strpcpyf(&s, l, "d%d", dev_id);
205 names->pci_path[0] = '\0';
207 /* ACPI _SUN -- slot user number */
208 pci = udev_device_new_from_subsystem_sysname(udev, "subsystem", "pci");
213 snprintf(slots, sizeof(slots), "%s/slots", udev_device_get_syspath(pci));
214 dir = opendir(slots);
220 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
225 if (dent->d_name[0] == '.')
227 i = strtol(dent->d_name, &rest, 10);
232 snprintf(str, sizeof(str), "%s/%s/address", slots, dent->d_name);
233 if (read_one_line_file(str, &address) >= 0) {
234 /* match slot address with device by stripping the function */
235 if (strneq(address, udev_device_get_sysname(names->pcidev), strlen(address)))
240 if (hotplug_slot > 0)
244 if (hotplug_slot > 0) {
246 l = sizeof(names->pci_slot);
248 l = strpcpyf(&s, l, "P%d", domain);
249 l = strpcpyf(&s, l, "s%d", hotplug_slot);
250 if (func > 0 || is_pci_multifunction(names->pcidev))
251 l = strpcpyf(&s, l, "f%d", func);
253 l = strpcpyf(&s, l, "d%d", dev_id);
255 names->pci_path[0] = '\0';
258 udev_device_unref(pci);
262 static int names_pci(struct udev_device *dev, struct netnames *names) {
263 struct udev_device *parent;
265 parent = udev_device_get_parent(dev);
268 /* check if our direct parent is a PCI device with no other bus in-between */
269 if (streq_ptr("pci", udev_device_get_subsystem(parent))) {
270 names->type = NET_PCI;
271 names->pcidev = parent;
273 names->pcidev = udev_device_get_parent_with_subsystem_devtype(dev, "pci", NULL);
277 dev_pci_onboard(dev, names);
278 dev_pci_slot(dev, names);
282 static int names_usb(struct udev_device *dev, struct netnames *names) {
283 struct udev_device *usbdev;
291 usbdev = udev_device_get_parent_with_subsystem_devtype(dev, "usb", "usb_interface");
295 /* get USB port number chain, configuration, interface */
296 strscpy(name, sizeof(name), udev_device_get_sysname(usbdev));
297 s = strchr(name, '-');
302 s = strchr(ports, ':');
308 s = strchr(config, '.');
314 /* prefix every port number in the chain with "u"*/
316 while ((s = strchr(s, '.')))
318 s = names->usb_ports;
319 l = strpcpyl(&s, sizeof(names->usb_ports), "u", ports, NULL);
321 /* append USB config number, suppress the common config == 1 */
322 if (!streq(config, "1"))
323 l = strpcpyl(&s, sizeof(names->usb_ports), "c", config, NULL);
325 /* append USB interface number, suppress the interface == 0 */
326 if (!streq(interf, "0"))
327 l = strpcpyl(&s, sizeof(names->usb_ports), "i", interf, NULL);
329 return -ENAMETOOLONG;
331 names->type = NET_USB;
335 static int names_bcma(struct udev_device *dev, struct netnames *names) {
336 struct udev_device *bcmadev;
339 bcmadev = udev_device_get_parent_with_subsystem_devtype(dev, "bcma", NULL);
343 /* bus num:core num */
344 if (sscanf(udev_device_get_sysname(bcmadev), "bcma%*u:%u", &core) != 1)
346 /* suppress the common core == 0 */
348 snprintf(names->bcma_core, sizeof(names->bcma_core), "b%u", core);
350 names->type = NET_BCMA;
354 static int names_virtio(struct udev_device *dev, struct netnames *names) {
355 struct udev_device *virtdev;
358 virtdev = udev_device_get_parent_with_subsystem_devtype(dev, "virtio", NULL);
363 if (sscanf(udev_device_get_sysname(virtdev), "virtio%u", &core) != 1)
365 /* suppress the common core == 0 */
367 snprintf(names->virtio_core, sizeof(names->virtio_core), "v%u", core);
369 names->type = NET_VIRTIO;
373 static int names_ccw(struct udev_device *dev, struct netnames *names) {
374 struct udev_device *cdev;
379 /* Retrieve the associated CCW device */
380 cdev = udev_device_get_parent(dev);
384 /* Network devices are always grouped CCW devices */
385 if (!streq_ptr("ccwgroup", udev_device_get_subsystem(cdev)))
388 /* Retrieve bus-ID of the grouped CCW device. The bus-ID uniquely
389 * identifies the network device on the Linux on System z channel
390 * subsystem. Note that the bus-ID contains lowercase characters.
392 bus_id = udev_device_get_sysname(cdev);
396 /* Check the length of the bus-ID. Rely on that the kernel provides
397 * a correct bus-ID; alternatively, improve this check and parse and
398 * verify each bus-ID part...
400 bus_id_len = strlen(bus_id);
401 if (!bus_id_len || bus_id_len < 8 || bus_id_len > 9)
404 /* Store the CCW bus-ID for use as network device name */
405 rc = snprintf(names->ccw_core, sizeof(names->ccw_core), "ccw%s", bus_id);
406 if (rc >= 0 && rc < (int)sizeof(names->ccw_core))
407 names->type = NET_CCWGROUP;
411 static int names_mac(struct udev_device *dev, struct netnames *names) {
414 unsigned int a1, a2, a3, a4, a5, a6;
416 /* check for NET_ADDR_PERM, skip random MAC addresses */
417 s = udev_device_get_sysattr_value(dev, "addr_assign_type");
420 i = strtoul(s, NULL, 0);
424 s = udev_device_get_sysattr_value(dev, "address");
427 if (sscanf(s, "%x:%x:%x:%x:%x:%x", &a1, &a2, &a3, &a4, &a5, &a6) != 6)
430 /* skip empty MAC addresses */
431 if (a1 + a2 + a3 + a4 + a5 + a6 == 0)
440 names->mac_valid = true;
444 /* IEEE Organizationally Unique Identifier vendor string */
445 static int ieee_oui(struct udev_device *dev, struct netnames *names, bool test) {
448 if (!names->mac_valid)
450 /* skip commonly misused 00:00:00 (Xerox) prefix */
451 if (memcmp(names->mac, "\0\0\0", 3) == 0)
453 snprintf(str, sizeof(str), "OUI:%02X%02X%02X%02X%02X%02X",
454 names->mac[0], names->mac[1], names->mac[2],
455 names->mac[3], names->mac[4], names->mac[5]);
456 udev_builtin_hwdb_lookup(dev, NULL, str, NULL, test);
460 static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool test) {
465 const char *prefix = "en";
466 struct netnames names = {};
469 /* handle only ARPHRD_ETHER and ARPHRD_SLIP devices */
470 s = udev_device_get_sysattr_value(dev, "type");
473 i = strtoul(s, NULL, 0);
475 case 1: /* ARPHRD_ETHER */
478 case 256: /* ARPHRD_SLIP */
485 /* skip stacked devices, like VLANs, ... */
486 s = udev_device_get_sysattr_value(dev, "ifindex");
489 p = udev_device_get_sysattr_value(dev, "iflink");
495 devtype = udev_device_get_devtype(dev);
497 if (streq("wlan", devtype))
499 else if (streq("wwan", devtype))
503 err = names_mac(dev, &names);
504 if (err >= 0 && names.mac_valid) {
507 snprintf(str, sizeof(str), "%sx%02x%02x%02x%02x%02x%02x", prefix,
508 names.mac[0], names.mac[1], names.mac[2],
509 names.mac[3], names.mac[4], names.mac[5]);
510 udev_builtin_add_property(dev, test, "ID_NET_NAME_MAC", str);
512 ieee_oui(dev, &names, test);
515 /* get path names for Linux on System z network devices */
516 err = names_ccw(dev, &names);
517 if (err >= 0 && names.type == NET_CCWGROUP) {
520 if (snprintf(str, sizeof(str), "%s%s", prefix, names.ccw_core) < (int)sizeof(str))
521 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
525 /* get PCI based path names, we compose only PCI based paths */
526 err = names_pci(dev, &names);
530 /* plain PCI device */
531 if (names.type == NET_PCI) {
534 if (names.pci_onboard[0])
535 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard) < (int)sizeof(str))
536 udev_builtin_add_property(dev, test, "ID_NET_NAME_ONBOARD", str);
538 if (names.pci_onboard_label)
539 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard_label) < (int)sizeof(str))
540 udev_builtin_add_property(dev, test, "ID_NET_LABEL_ONBOARD", str);
542 if (names.pci_path[0])
543 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_path) < (int)sizeof(str))
544 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
546 if (names.pci_slot[0])
547 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_slot) < (int)sizeof(str))
548 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
553 err = names_usb(dev, &names);
554 if (err >= 0 && names.type == NET_USB) {
557 if (names.pci_path[0])
558 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.usb_ports) < (int)sizeof(str))
559 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
561 if (names.pci_slot[0])
562 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.usb_ports) < (int)sizeof(str))
563 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
568 err = names_bcma(dev, &names);
569 if (err >= 0 && names.type == NET_BCMA) {
572 if (names.pci_path[0])
573 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.bcma_core) < (int)sizeof(str))
574 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
576 if (names.pci_slot[0])
577 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.bcma_core) < (int)sizeof(str))
578 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
583 err = names_virtio(dev, &names);
584 if (err >= 0 && names.type == NET_VIRTIO) {
587 if (names.pci_path[0])
588 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.virtio_core) < (int)sizeof(str))
589 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
591 if (names.pci_slot[0])
592 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.virtio_core) < (int)sizeof(str))
593 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
601 const struct udev_builtin udev_builtin_net_id = {
603 .cmd = builtin_net_id,
604 .help = "network device properties",