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 * x<MAC> -- MAC address
41 * [P<domain>]p<bus>s<slot>[f<function>][d<dev_id>]
42 * -- PCI geographical location
43 * [P<domain>]p<bus>s<slot>[f<function>][u<port>][..][c<config>][i<interface>]
44 * -- USB port number chain
46 * All multi-function PCI devices will carry the [f<function>] number in the
47 * device name, including the function 0 device.
49 * When using PCI geography, The PCI domain is only prepended when it is not 0.
51 * For USB devices the full chain of port numbers of hubs is composed. If the
52 * name gets longer than the maximum number of 15 characters, the name is not
54 * The usual USB configuration == 1 and interface == 0 values are suppressed.
56 * PCI ethernet card with firmware index "1":
57 * ID_NET_NAME_ONBOARD=eno1
58 * ID_NET_NAME_ONBOARD_LABEL=Ethernet Port 1
60 * PCI ethernet card in hotplug slot with firmware index number:
61 * /sys/devices/pci0000:00/0000:00:1c.3/0000:05:00.0/net/ens1
62 * ID_NET_NAME_MAC=enx000000000466
63 * ID_NET_NAME_PATH=enp5s0
64 * ID_NET_NAME_SLOT=ens1
66 * PCI ethernet multi-function card with 2 ports:
67 * /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.0/net/enp2s0f0
68 * ID_NET_NAME_MAC=enx78e7d1ea46da
69 * ID_NET_NAME_PATH=enp2s0f0
70 * /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.1/net/enp2s0f1
71 * ID_NET_NAME_MAC=enx78e7d1ea46dc
72 * ID_NET_NAME_PATH=enp2s0f1
75 * /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlp3s0
76 * ID_NET_NAME_MAC=wlx0024d7e31130
77 * ID_NET_NAME_PATH=wlp3s0
79 * USB built-in 3G modem:
80 * /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.6/net/wwp0s29u1u4i6
81 * ID_NET_NAME_MAC=wwx028037ec0200
82 * ID_NET_NAME_PATH=wwp0s29u1u4i6
85 * /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/net/enp0s29u1u2
86 * ID_NET_NAME_MAC=enxd626b3450fb5
87 * ID_NET_NAME_PATH=enp0s29u1u2
97 #include <net/if_arp.h>
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 ccw_group[IFNAMSIZ];
129 /* retrieve on-board index number and label from firmware */
130 static int dev_pci_onboard(struct udev_device *dev, struct netnames *names) {
134 /* ACPI _DSM -- device specific method for naming a PCI or PCI Express device */
135 index = udev_device_get_sysattr_value(names->pcidev, "acpi_index");
136 /* SMBIOS type 41 -- Onboard Devices Extended Information */
138 index = udev_device_get_sysattr_value(names->pcidev, "index");
141 idx = strtoul(index, NULL, 0);
144 snprintf(names->pci_onboard, sizeof(names->pci_onboard), "o%d", idx);
146 names->pci_onboard_label = udev_device_get_sysattr_value(names->pcidev, "label");
150 /* read the 256 bytes PCI configuration space to check the multi-function bit */
151 static bool is_pci_multifunction(struct udev_device *dev) {
157 snprintf(filename, sizeof(filename), "%s/config", udev_device_get_syspath(dev));
158 f = fopen(filename, "re");
161 if (fread(&config, sizeof(config), 1, f) != 1)
164 /* bit 0-6 header type, bit 7 multi/single function device */
165 if ((config[PCI_HEADER_TYPE] & 0x80) != 0)
173 static int dev_pci_slot(struct udev_device *dev, struct netnames *names) {
174 struct udev *udev = udev_device_get_udev(names->pcidev);
175 unsigned domain, bus, slot, func, dev_id = 0;
179 struct udev_device *pci = NULL;
180 char slots[256], str[256];
181 _cleanup_closedir_ DIR *dir = NULL;
183 int hotplug_slot = 0, err = 0;
185 if (sscanf(udev_device_get_sysname(names->pcidev), "%x:%x:%x.%u", &domain, &bus, &slot, &func) != 4)
188 /* kernel provided multi-device index */
189 attr = udev_device_get_sysattr_value(dev, "dev_id");
191 dev_id = strtol(attr, NULL, 16);
193 /* compose a name based on the raw kernel's PCI bus, slot numbers */
195 l = sizeof(names->pci_path);
197 l = strpcpyf(&s, l, "P%d", domain);
198 l = strpcpyf(&s, l, "p%ds%d", bus, slot);
199 if (func > 0 || is_pci_multifunction(names->pcidev))
200 l = strpcpyf(&s, l, "f%d", func);
202 l = strpcpyf(&s, l, "d%d", dev_id);
204 names->pci_path[0] = '\0';
206 /* ACPI _SUN -- slot user number */
207 pci = udev_device_new_from_subsystem_sysname(udev, "subsystem", "pci");
212 snprintf(slots, sizeof(slots), "%s/slots", udev_device_get_syspath(pci));
213 dir = opendir(slots);
219 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
224 if (dent->d_name[0] == '.')
226 i = strtol(dent->d_name, &rest, 10);
231 snprintf(str, sizeof(str), "%s/%s/address", slots, dent->d_name);
232 if (read_one_line_file(str, &address) >= 0) {
233 /* match slot address with device by stripping the function */
234 if (strneq(address, udev_device_get_sysname(names->pcidev), strlen(address)))
239 if (hotplug_slot > 0)
243 if (hotplug_slot > 0) {
245 l = sizeof(names->pci_slot);
247 l = strpcpyf(&s, l, "P%d", domain);
248 l = strpcpyf(&s, l, "s%d", hotplug_slot);
249 if (func > 0 || is_pci_multifunction(names->pcidev))
250 l = strpcpyf(&s, l, "f%d", func);
252 l = strpcpyf(&s, l, "d%d", dev_id);
254 names->pci_path[0] = '\0';
257 udev_device_unref(pci);
261 static int names_pci(struct udev_device *dev, struct netnames *names) {
262 struct udev_device *parent;
264 parent = udev_device_get_parent(dev);
267 /* check if our direct parent is a PCI device with no other bus in-between */
268 if (streq_ptr("pci", udev_device_get_subsystem(parent))) {
269 names->type = NET_PCI;
270 names->pcidev = parent;
272 names->pcidev = udev_device_get_parent_with_subsystem_devtype(dev, "pci", NULL);
276 dev_pci_onboard(dev, names);
277 dev_pci_slot(dev, names);
281 static int names_usb(struct udev_device *dev, struct netnames *names) {
282 struct udev_device *usbdev;
290 usbdev = udev_device_get_parent_with_subsystem_devtype(dev, "usb", "usb_interface");
294 /* get USB port number chain, configuration, interface */
295 strscpy(name, sizeof(name), udev_device_get_sysname(usbdev));
296 s = strchr(name, '-');
301 s = strchr(ports, ':');
307 s = strchr(config, '.');
313 /* prefix every port number in the chain with "u"*/
315 while ((s = strchr(s, '.')))
317 s = names->usb_ports;
318 l = strpcpyl(&s, sizeof(names->usb_ports), "u", ports, NULL);
320 /* append USB config number, suppress the common config == 1 */
321 if (!streq(config, "1"))
322 l = strpcpyl(&s, sizeof(names->usb_ports), "c", config, NULL);
324 /* append USB interface number, suppress the interface == 0 */
325 if (!streq(interf, "0"))
326 l = strpcpyl(&s, sizeof(names->usb_ports), "i", interf, NULL);
328 return -ENAMETOOLONG;
330 names->type = NET_USB;
334 static int names_bcma(struct udev_device *dev, struct netnames *names) {
335 struct udev_device *bcmadev;
338 bcmadev = udev_device_get_parent_with_subsystem_devtype(dev, "bcma", NULL);
342 /* bus num:core num */
343 if (sscanf(udev_device_get_sysname(bcmadev), "bcma%*u:%u", &core) != 1)
345 /* suppress the common core == 0 */
347 snprintf(names->bcma_core, sizeof(names->bcma_core), "b%u", core);
349 names->type = NET_BCMA;
353 static int names_ccw(struct udev_device *dev, struct netnames *names) {
354 struct udev_device *cdev;
359 /* Retrieve the associated CCW device */
360 cdev = udev_device_get_parent(dev);
364 /* Network devices are always grouped CCW devices */
365 if (!streq_ptr("ccwgroup", udev_device_get_subsystem(cdev)))
368 /* Retrieve bus-ID of the grouped CCW device. The bus-ID uniquely
369 * identifies the network device on the Linux on System z channel
370 * subsystem. Note that the bus-ID contains lowercase characters.
372 bus_id = udev_device_get_sysname(cdev);
376 /* Check the length of the bus-ID. Rely on that the kernel provides
377 * a correct bus-ID; alternatively, improve this check and parse and
378 * verify each bus-ID part...
380 bus_id_len = strlen(bus_id);
381 if (!bus_id_len || bus_id_len < 8 || bus_id_len > 9)
384 /* Store the CCW bus-ID for use as network device name */
385 rc = snprintf(names->ccw_group, sizeof(names->ccw_group), "ccw%s", bus_id);
386 if (rc >= 0 && rc < (int)sizeof(names->ccw_group))
387 names->type = NET_CCWGROUP;
391 static int names_mac(struct udev_device *dev, struct netnames *names) {
394 unsigned int a1, a2, a3, a4, a5, a6;
396 /* check for NET_ADDR_PERM, skip random MAC addresses */
397 s = udev_device_get_sysattr_value(dev, "addr_assign_type");
400 i = strtoul(s, NULL, 0);
404 s = udev_device_get_sysattr_value(dev, "address");
407 if (sscanf(s, "%x:%x:%x:%x:%x:%x", &a1, &a2, &a3, &a4, &a5, &a6) != 6)
410 /* skip empty MAC addresses */
411 if (a1 + a2 + a3 + a4 + a5 + a6 == 0)
420 names->mac_valid = true;
424 /* IEEE Organizationally Unique Identifier vendor string */
425 static int ieee_oui(struct udev_device *dev, struct netnames *names, bool test) {
428 if (!names->mac_valid)
430 /* skip commonly misused 00:00:00 (Xerox) prefix */
431 if (memcmp(names->mac, "\0\0\0", 3) == 0)
433 snprintf(str, sizeof(str), "OUI:%02X%02X%02X%02X%02X%02X",
434 names->mac[0], names->mac[1], names->mac[2],
435 names->mac[3], names->mac[4], names->mac[5]);
436 udev_builtin_hwdb_lookup(dev, NULL, str, NULL, test);
440 static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool test) {
445 const char *prefix = "en";
446 struct netnames names = {};
449 /* handle only ARPHRD_ETHER and ARPHRD_SLIP devices */
450 s = udev_device_get_sysattr_value(dev, "type");
453 i = strtoul(s, NULL, 0);
465 /* skip stacked devices, like VLANs, ... */
466 s = udev_device_get_sysattr_value(dev, "ifindex");
469 p = udev_device_get_sysattr_value(dev, "iflink");
475 devtype = udev_device_get_devtype(dev);
477 if (streq("wlan", devtype))
479 else if (streq("wwan", devtype))
483 err = names_mac(dev, &names);
484 if (err >= 0 && names.mac_valid) {
487 snprintf(str, sizeof(str), "%sx%02x%02x%02x%02x%02x%02x", prefix,
488 names.mac[0], names.mac[1], names.mac[2],
489 names.mac[3], names.mac[4], names.mac[5]);
490 udev_builtin_add_property(dev, test, "ID_NET_NAME_MAC", str);
492 ieee_oui(dev, &names, test);
495 /* get path names for Linux on System z network devices */
496 err = names_ccw(dev, &names);
497 if (err >= 0 && names.type == NET_CCWGROUP) {
500 if (snprintf(str, sizeof(str), "%s%s", prefix, names.ccw_group) < (int)sizeof(str))
501 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
505 /* get PCI based path names, we compose only PCI based paths */
506 err = names_pci(dev, &names);
510 /* plain PCI device */
511 if (names.type == NET_PCI) {
514 if (names.pci_onboard[0])
515 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard) < (int)sizeof(str))
516 udev_builtin_add_property(dev, test, "ID_NET_NAME_ONBOARD", str);
518 if (names.pci_onboard_label)
519 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard_label) < (int)sizeof(str))
520 udev_builtin_add_property(dev, test, "ID_NET_LABEL_ONBOARD", str);
522 if (names.pci_path[0])
523 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_path) < (int)sizeof(str))
524 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
526 if (names.pci_slot[0])
527 if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_slot) < (int)sizeof(str))
528 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
533 err = names_usb(dev, &names);
534 if (err >= 0 && names.type == NET_USB) {
537 if (names.pci_path[0])
538 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.usb_ports) < (int)sizeof(str))
539 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
541 if (names.pci_slot[0])
542 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.usb_ports) < (int)sizeof(str))
543 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
548 err = names_bcma(dev, &names);
549 if (err >= 0 && names.type == NET_BCMA) {
552 if (names.pci_path[0])
553 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.bcma_core) < (int)sizeof(str))
554 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
556 if (names.pci_slot[0])
557 if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.bcma_core) < (int)sizeof(str))
558 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
565 const struct udev_builtin udev_builtin_net_id = {
567 .cmd = builtin_net_id,
568 .help = "network device properties",