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 * b<number> -- BCMA bus core number
37 * ccw<name> -- CCW bus group name
38 * o<index> -- on-board device index number
39 * s<slot>[f<function>][d<dev_id>] -- hotplug slot index number
40 * v<number> -- virtio number
41 * x<MAC> -- MAC address
42 * [P<domain>]p<bus>s<slot>[f<function>][d<dev_id>]
43 * -- PCI geographical location
44 * [P<domain>]p<bus>s<slot>[f<function>][u<port>][..][c<config>][i<interface>]
45 * -- USB port number chain
47 * All multi-function PCI devices will carry the [f<function>] number in the
48 * device name, including the function 0 device.
50 * When using PCI geography, The PCI domain is only prepended when it is not 0.
52 * For USB devices the full chain of port numbers of hubs is composed. If the
53 * name gets longer than the maximum number of 15 characters, the name is not
55 * The usual USB configuration == 1 and interface == 0 values are suppressed.
57 * PCI ethernet card with firmware index "1":
58 * ID_NET_NAME_ONBOARD=eno1
59 * ID_NET_NAME_ONBOARD_LABEL=Ethernet Port 1
61 * PCI ethernet card in hotplug slot with firmware index number:
62 * /sys/devices/pci0000:00/0000:00:1c.3/0000:05:00.0/net/ens1
63 * ID_NET_NAME_MAC=enx000000000466
64 * ID_NET_NAME_PATH=enp5s0
65 * ID_NET_NAME_SLOT=ens1
67 * PCI ethernet multi-function card with 2 ports:
68 * /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.0/net/enp2s0f0
69 * ID_NET_NAME_MAC=enx78e7d1ea46da
70 * ID_NET_NAME_PATH=enp2s0f0
71 * /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.1/net/enp2s0f1
72 * ID_NET_NAME_MAC=enx78e7d1ea46dc
73 * ID_NET_NAME_PATH=enp2s0f1
76 * /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlp3s0
77 * ID_NET_NAME_MAC=wlx0024d7e31130
78 * ID_NET_NAME_PATH=wlp3s0
80 * USB built-in 3G modem:
81 * /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.6/net/wwp0s29u1u4i6
82 * ID_NET_NAME_MAC=wwx028037ec0200
83 * ID_NET_NAME_PATH=wwp0s29u1u4i6
86 * /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/net/enp0s29u1u2
87 * ID_NET_NAME_MAC=enxd626b3450fb5
88 * ID_NET_NAME_PATH=enp0s29u1u2
98 #include <linux/pci_regs.h>
113 enum netname_type type;
118 struct udev_device *pcidev;
119 char pci_slot[IFNAMSIZ];
120 char pci_path[IFNAMSIZ];
121 char pci_onboard[IFNAMSIZ];
122 const char *pci_onboard_label;
124 char usb_ports[IFNAMSIZ];
125 char bcma_core[IFNAMSIZ];
126 char virtio[IFNAMSIZ];
127 char ccw_group[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);
362 if (sscanf(udev_device_get_sysname(virtdev), "virtio%u", &num) != 1)
364 /* suppress the common num == 0 */
366 snprintf(names->virtio, sizeof(names->virtio), "v%u", num);
368 names->type = NET_VIRTIO;
372 static int names_ccw(struct udev_device *dev, struct netnames *names) {
373 struct udev_device *cdev;
378 /* Retrieve the associated CCW device */
379 cdev = udev_device_get_parent(dev);
383 /* Network devices are always grouped CCW devices */
384 if (!streq_ptr("ccwgroup", udev_device_get_subsystem(cdev)))
387 /* Retrieve bus-ID of the grouped CCW device. The bus-ID uniquely
388 * identifies the network device on the Linux on System z channel
389 * subsystem. Note that the bus-ID contains lowercase characters.
391 bus_id = udev_device_get_sysname(cdev);
395 /* Check the length of the bus-ID. Rely on that the kernel provides
396 * a correct bus-ID; alternatively, improve this check and parse and
397 * verify each bus-ID part...
399 bus_id_len = strlen(bus_id);
400 if (!bus_id_len || bus_id_len < 8 || bus_id_len > 9)
403 /* Store the CCW bus-ID for use as network device name */
404 rc = snprintf(names->ccw_group, sizeof(names->ccw_group), "ccw%s", bus_id);
405 if (rc >= 0 && rc < (int)sizeof(names->ccw_group))
406 names->type = NET_CCWGROUP;
410 static int names_mac(struct udev_device *dev, struct netnames *names) {
413 unsigned int a1, a2, a3, a4, a5, a6;
415 /* check for NET_ADDR_PERM, skip random MAC addresses */
416 s = udev_device_get_sysattr_value(dev, "addr_assign_type");
419 i = strtoul(s, NULL, 0);
423 s = udev_device_get_sysattr_value(dev, "address");
426 if (sscanf(s, "%x:%x:%x:%x:%x:%x", &a1, &a2, &a3, &a4, &a5, &a6) != 6)
429 /* skip empty MAC addresses */
430 if (a1 + a2 + a3 + a4 + a5 + a6 == 0)
439 names->mac_valid = true;
443 /* IEEE Organizationally Unique Identifier vendor string */
444 static int ieee_oui(struct udev_device *dev, struct netnames *names, bool test) {
447 if (!names->mac_valid)
449 /* skip commonly misused 00:00:00 (Xerox) prefix */
450 if (memcmp(names->mac, "\0\0\0", 3) == 0)
452 snprintf(str, sizeof(str), "OUI:%02X%02X%02X%02X%02X%02X",
453 names->mac[0], names->mac[1], names->mac[2],
454 names->mac[3], names->mac[4], names->mac[5]);
455 udev_builtin_hwdb_lookup(dev, NULL, str, NULL, test);
459 static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool test) {
464 const char *prefix = "en";
465 struct netnames names = {};
468 /* handle only ARPHRD_ETHER and ARPHRD_SLIP devices */
469 s = udev_device_get_sysattr_value(dev, "type");
472 i = strtoul(s, NULL, 0);
474 case 1: /* ARPHRD_ETHER */
477 case 256: /* ARPHRD_SLIP */
484 /* skip stacked devices, like VLANs, ... */
485 s = udev_device_get_sysattr_value(dev, "ifindex");
488 p = udev_device_get_sysattr_value(dev, "iflink");
494 devtype = udev_device_get_devtype(dev);
496 if (streq("wlan", devtype))
498 else if (streq("wwan", devtype))
502 err = names_mac(dev, &names);
503 if (err >= 0 && names.mac_valid) {
506 snprintf(str, sizeof(str), "%sx%02x%02x%02x%02x%02x%02x", prefix,
507 names.mac[0], names.mac[1], names.mac[2],
508 names.mac[3], names.mac[4], names.mac[5]);
509 udev_builtin_add_property(dev, test, "ID_NET_NAME_MAC", str);
511 ieee_oui(dev, &names, test);
514 /* get path names for Linux on System z network devices */
515 err = names_ccw(dev, &names);
516 if (err >= 0 && names.type == NET_CCWGROUP) {
519 if (snprintf(str, sizeof(str), "%s%s", prefix, names.ccw_group) < (int)sizeof(str))
520 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
524 /* get PCI based path names, we compose only PCI based paths */
525 err = names_pci(dev, &names);
529 /* plain PCI device */
530 if (names.type == NET_PCI) {
533 if (names.pci_onboard[0])
534 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard) < (int)sizeof(str))
535 udev_builtin_add_property(dev, test, "ID_NET_NAME_ONBOARD", str);
537 if (names.pci_onboard_label)
538 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard_label) < (int)sizeof(str))
539 udev_builtin_add_property(dev, test, "ID_NET_LABEL_ONBOARD", str);
541 if (names.pci_path[0])
542 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_path) < (int)sizeof(str))
543 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
545 if (names.pci_slot[0])
546 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_slot) < (int)sizeof(str))
547 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
552 err = names_usb(dev, &names);
553 if (err >= 0 && names.type == NET_USB) {
556 if (names.pci_path[0])
557 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.usb_ports) < (int)sizeof(str))
558 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
560 if (names.pci_slot[0])
561 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.usb_ports) < (int)sizeof(str))
562 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
567 err = names_bcma(dev, &names);
568 if (err >= 0 && names.type == NET_BCMA) {
571 if (names.pci_path[0])
572 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.bcma_core) < (int)sizeof(str))
573 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
575 if (names.pci_slot[0])
576 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.bcma_core) < (int)sizeof(str))
577 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
582 err = names_virtio(dev, &names);
583 if (err >= 0 && names.type == NET_VIRTIO) {
586 if (names.pci_path[0])
587 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.virtio) < (int)sizeof(str))
588 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
590 if (names.pci_slot[0])
591 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.virtio) < (int)sizeof(str))
592 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
600 const struct udev_builtin udev_builtin_net_id = {
602 .cmd = builtin_net_id,
603 .help = "network device properties",