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<bus>s<slot>[f<function>][d<dev_id>] -- PCI geographical location
39 * p<bus>s<slot>[f<function>][u<port>][..][c<config>][i<interface>]
40 * -- USB port number chain
42 * All multi-function PCI devices will carry the [f<function>] number in the
43 * device name, including the function 0 device.
45 * For USB devices the full chain of port numbers of hubs is composed. If the
46 * name gets longer than the maximum number of 15 characters, the name is not
48 * The usual USB configuration == 1 and interface == 0 values are suppressed.
50 * PCI ethernet card with firmware index "1":
51 * ID_NET_NAME_ONBOARD=eno1
52 * ID_NET_NAME_ONBOARD_LABEL=Ethernet Port 1
54 * PCI ethernet card in hotplug slot with firmware index number:
55 * /sys/devices/pci0000:00/0000:00:1c.3/0000:05:00.0/net/ens1
56 * ID_NET_NAME_MAC=enx000000000466
57 * ID_NET_NAME_PATH=enp5s0
58 * ID_NET_NAME_SLOT=ens1
60 * PCI ethernet multi-function card with 2 ports:
61 * /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.0/net/enp2s0f0
62 * ID_NET_NAME_MAC=enx78e7d1ea46da
63 * ID_NET_NAME_PATH=enp2s0f0
64 * /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.1/net/enp2s0f1
65 * ID_NET_NAME_MAC=enx78e7d1ea46dc
66 * ID_NET_NAME_PATH=enp2s0f1
69 * /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlp3s0
70 * ID_NET_NAME_MAC=wlx0024d7e31130
71 * ID_NET_NAME_PATH=wlp3s0
73 * USB built-in 3G modem:
74 * /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.6/net/wwp0s29u1u4i6
75 * ID_NET_NAME_MAC=wwx028037ec0200
76 * ID_NET_NAME_PATH=wwp0s29u1u4i6
79 * /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/net/enp0s29u1u2
80 * ID_NET_NAME_MAC=enxd626b3450fb5
81 * ID_NET_NAME_PATH=enp0s29u1u2
91 #include <linux/pci_regs.h>
103 enum netname_type type;
108 struct udev_device *pcidev;
109 char pci_slot[IFNAMSIZ];
110 char pci_path[IFNAMSIZ];
111 char pci_onboard[IFNAMSIZ];
112 const char *pci_onboard_label;
114 char usb_ports[IFNAMSIZ];
116 char bcma_core[IFNAMSIZ];
119 /* retrieve on-board index number and label from firmware */
120 static int dev_pci_onboard(struct udev_device *dev, struct netnames *names) {
124 /* ACPI _DSM -- device specific method for naming a PCI or PCI Express device */
125 index = udev_device_get_sysattr_value(names->pcidev, "acpi_index");
126 /* SMBIOS type 41 -- Onboard Devices Extended Information */
128 index = udev_device_get_sysattr_value(names->pcidev, "index");
131 idx = strtoul(index, NULL, 0);
134 snprintf(names->pci_onboard, sizeof(names->pci_onboard), "o%d", idx);
136 names->pci_onboard_label = udev_device_get_sysattr_value(names->pcidev, "label");
140 /* read the 256 bytes PCI configuration space to check the multi-function bit */
141 static bool is_pci_multifunction(struct udev_device *dev) {
147 snprintf(filename, sizeof(filename), "%s/config", udev_device_get_syspath(dev));
148 f = fopen(filename, "re");
151 if (fread(&config, sizeof(config), 1, f) != 1)
154 /* bit 0-6 header type, bit 7 multi/single function device */
155 if ((config[PCI_HEADER_TYPE] & 0x80) != 0)
163 static int dev_pci_slot(struct udev_device *dev, struct netnames *names) {
164 struct udev *udev = udev_device_get_udev(names->pcidev);
168 unsigned int dev_id = 0;
172 struct udev_device *pci = NULL;
177 int hotplug_slot = 0;
180 if (sscanf(udev_device_get_sysname(names->pcidev), "0000:%x:%x.%d", &bus, &slot, &func) != 3)
183 /* kernel provided multi-device index */
184 attr = udev_device_get_sysattr_value(dev, "dev_id");
186 dev_id = strtol(attr, NULL, 16);
188 /* compose a name based on the raw kernel's PCI bus, slot numbers */
190 l = strpcpyf(&s, sizeof(names->pci_path), "p%ds%d", bus, slot);
191 if (func > 0 || is_pci_multifunction(names->pcidev))
192 l = strpcpyf(&s, l, "f%d", func);
194 l = strpcpyf(&s, l, "d%d", dev_id);
196 names->pci_path[0] = '\0';
198 /* ACPI _SUN -- slot user number */
199 pci = udev_device_new_from_subsystem_sysname(udev, "subsystem", "pci");
204 snprintf(slots, sizeof(slots), "%s/slots", udev_device_get_syspath(pci));
205 dir = opendir(slots);
211 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
216 if (dent->d_name[0] == '.')
218 i = strtol(dent->d_name, &rest, 10);
223 snprintf(str, sizeof(str), "%s/%s/address", slots, dent->d_name);
224 if (read_one_line_file(str, &address) >= 0) {
225 /* match slot address with device by stripping the function */
226 if (strncmp(address, udev_device_get_sysname(names->pcidev), strlen(address)) == 0)
231 if (hotplug_slot > 0)
236 if (hotplug_slot > 0) {
238 l = strpcpyf(&s, sizeof(names->pci_slot), "s%d", hotplug_slot);
239 if (func > 0 || is_pci_multifunction(names->pcidev))
240 l = strpcpyf(&s, l, "f%d", func);
242 l = strpcpyf(&s, l, "d%d", dev_id);
244 names->pci_path[0] = '\0';
247 udev_device_unref(pci);
251 static int names_pci(struct udev_device *dev, struct netnames *names) {
252 struct udev_device *parent;
254 parent = udev_device_get_parent(dev);
257 /* check if our direct parent is a PCI device with no other bus in-between */
258 if (streq("pci", udev_device_get_subsystem(parent))) {
259 names->type = NET_PCI;
260 names->pcidev = parent;
262 names->pcidev = udev_device_get_parent_with_subsystem_devtype(dev, "pci", NULL);
266 dev_pci_onboard(dev, names);
267 dev_pci_slot(dev, names);
271 static int names_usb(struct udev_device *dev, struct netnames *names) {
272 struct udev_device *usbdev;
280 usbdev = udev_device_get_parent_with_subsystem_devtype(dev, "usb", "usb_interface");
284 /* get USB port number chain, configuration, interface */
285 strscpy(name, sizeof(name), udev_device_get_sysname(usbdev));
286 s = strchr(name, '-');
291 s = strchr(ports, ':');
297 s = strchr(config, '.');
303 /* prefix every port number in the chain with "u"*/
305 while ((s = strchr(s, '.')))
307 s = names->usb_ports;
308 l = strpcpyl(&s, sizeof(names->usb_ports), "u", ports, NULL);
310 /* append USB config number, suppress the common config == 1 */
311 if (!streq(config, "1"))
312 l = strpcpyl(&s, sizeof(names->usb_ports), "c", config, NULL);
314 /* append USB interface number, suppress the interface == 0 */
315 if (!streq(interf, "0"))
316 l = strpcpyl(&s, sizeof(names->usb_ports), "i", interf, NULL);
318 return -ENAMETOOLONG;
320 names->type = NET_USB;
324 static int names_bcma(struct udev_device *dev, struct netnames *names) {
325 struct udev_device *bcmadev;
328 bcmadev = udev_device_get_parent_with_subsystem_devtype(dev, "bcma", NULL);
332 /* bus num:core num */
333 if (sscanf(udev_device_get_sysname(bcmadev), "bcma%*d:%d", &core) != 1)
335 /* suppress the common core == 0 */
337 snprintf(names->bcma_core, sizeof(names->bcma_core), "b%d", core);
339 names->type = NET_BCMA;
343 static int names_mac(struct udev_device *dev, struct netnames *names) {
346 unsigned int a1, a2, a3, a4, a5, a6;
348 /* check for NET_ADDR_PERM, skip random MAC addresses */
349 s = udev_device_get_sysattr_value(dev, "addr_assign_type");
352 i = strtoul(s, NULL, 0);
356 s = udev_device_get_sysattr_value(dev, "address");
359 if (sscanf(s, "%x:%x:%x:%x:%x:%x", &a1, &a2, &a3, &a4, &a5, &a6) != 6)
362 /* skip empty MAC addresses */
363 if (a1 + a2 + a3 + a4 + a5 + a6 == 0)
372 names->mac_valid = true;
376 /* IEEE Organizationally Unique Identifier vendor string */
377 static int ieee_oui(struct udev_device *dev, struct netnames *names, bool test) {
380 if (!names->mac_valid)
382 /* skip commonly misused 00:00:00 (Xerox) prefix */
383 if (memcmp(names->mac, "\0\0\0", 3) == 0)
385 snprintf(str, sizeof(str), "OUI:%02X%02X%02X%02X%02X%02X",
386 names->mac[0], names->mac[1], names->mac[2],
387 names->mac[3], names->mac[4], names->mac[5]);
388 udev_builtin_hwdb_lookup(dev, str, test);
392 static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool test) {
397 const char *prefix = "en";
398 struct netnames names;
401 /* handle only ARPHRD_ETHER devices */
402 s = udev_device_get_sysattr_value(dev, "type");
405 i = strtoul(s, NULL, 0);
409 /* skip stacked devices, like VLANs, ... */
410 s = udev_device_get_sysattr_value(dev, "ifindex");
413 p = udev_device_get_sysattr_value(dev, "iflink");
416 if (strcmp(s, p) != 0)
419 devtype = udev_device_get_devtype(dev);
421 if (streq("wlan", devtype))
423 else if (streq("wwan", devtype))
428 err = names_mac(dev, &names);
429 if (err >= 0 && names.mac_valid) {
432 snprintf(str, sizeof(str), "%sx%02x%02x%02x%02x%02x%02x", prefix,
433 names.mac[0], names.mac[1], names.mac[2],
434 names.mac[3], names.mac[4], names.mac[5]);
435 udev_builtin_add_property(dev, test, "ID_NET_NAME_MAC", str);
437 ieee_oui(dev, &names, test);
440 /* get PCI based path names, we compose only PCI based paths */
441 err = names_pci(dev, &names);
445 /* plain PCI device */
446 if (names.type == NET_PCI) {
449 if (names.pci_onboard[0])
450 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard) < (int)sizeof(str))
451 udev_builtin_add_property(dev, test, "ID_NET_NAME_ONBOARD", str);
453 if (names.pci_onboard_label)
454 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard_label) < (int)sizeof(str))
455 udev_builtin_add_property(dev, test, "ID_NET_LABEL_ONBOARD", str);
457 if (names.pci_path[0])
458 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_path) < (int)sizeof(str))
459 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
461 if (names.pci_slot[0])
462 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_slot) < (int)sizeof(str))
463 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
468 err = names_usb(dev, &names);
469 if (err >= 0 && names.type == NET_USB) {
472 if (names.pci_path[0])
473 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.usb_ports) < (int)sizeof(str))
474 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
476 if (names.pci_slot[0])
477 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.usb_ports) < (int)sizeof(str))
478 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
483 err = names_bcma(dev, &names);
484 if (err >= 0 && names.type == NET_BCMA) {
487 if (names.pci_path[0])
488 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.bcma_core) < (int)sizeof(str))
489 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
491 if (names.pci_slot[0])
492 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.bcma_core) < (int)sizeof(str))
493 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
501 const struct udev_builtin udev_builtin_net_id = {
503 .cmd = builtin_net_id,
504 .help = "network device properties",