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 * c<bus_id> — CCW bus group name, without leading zeros [s390]
38 * o<index>[d<dev_port>] — on-board device index number
39 * s<slot>[f<function>][d<dev_port>] — hotplug slot index number
40 * x<MAC> — MAC address
41 * [P<domain>]p<bus>s<slot>[f<function>][d<dev_port>]
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
93 #include <net/if_arp.h>
99 #include <linux/pci_regs.h>
103 #include "stdio-util.h"
104 #include "string-util.h"
107 #define ONBOARD_INDEX_MAX (16*1024-1)
119 enum netname_type type
;
124 struct udev_device
*pcidev
;
125 char pci_slot
[IFNAMSIZ
];
126 char pci_path
[IFNAMSIZ
];
127 char pci_onboard
[IFNAMSIZ
];
128 const char *pci_onboard_label
;
130 char usb_ports
[IFNAMSIZ
];
131 char bcma_core
[IFNAMSIZ
];
132 char ccw_group
[IFNAMSIZ
];
135 /* retrieve on-board index number and label from firmware */
136 static int dev_pci_onboard(struct udev_device
*dev
, struct netnames
*names
) {
137 unsigned dev_port
= 0;
143 /* ACPI _DSM — device specific method for naming a PCI or PCI Express device */
144 attr
= udev_device_get_sysattr_value(names
->pcidev
, "acpi_index");
145 /* SMBIOS type 41 — Onboard Devices Extended Information */
147 attr
= udev_device_get_sysattr_value(names
->pcidev
, "index");
151 idx
= strtoul(attr
, NULL
, 0);
155 /* Some BIOSes report rubbish indexes that are excessively high (2^24-1 is an index VMware likes to report for
156 * example). Let's define a cut-off where we don't consider the index reliable anymore. We pick some arbitrary
157 * cut-off, which is somewhere beyond the realistic number of physical network interface a system might
158 * have. Ideally the kernel would already filter his crap for us, but it doesn't currently. */
159 if (idx
> ONBOARD_INDEX_MAX
)
162 /* kernel provided port index for multiple ports on a single PCI function */
163 attr
= udev_device_get_sysattr_value(dev
, "dev_port");
165 dev_port
= strtol(attr
, NULL
, 10);
167 s
= names
->pci_onboard
;
168 l
= sizeof(names
->pci_onboard
);
169 l
= strpcpyf(&s
, l
, "o%d", idx
);
171 l
= strpcpyf(&s
, l
, "d%d", dev_port
);
173 names
->pci_onboard
[0] = '\0';
175 names
->pci_onboard_label
= udev_device_get_sysattr_value(names
->pcidev
, "label");
180 /* read the 256 bytes PCI configuration space to check the multi-function bit */
181 static bool is_pci_multifunction(struct udev_device
*dev
) {
182 _cleanup_close_
int fd
= -1;
183 const char *filename
;
186 filename
= strjoina(udev_device_get_syspath(dev
), "/config");
187 fd
= open(filename
, O_RDONLY
| O_CLOEXEC
);
190 if (read(fd
, &config
, sizeof(config
)) != sizeof(config
))
193 /* bit 0-6 header type, bit 7 multi/single function device */
194 if ((config
[PCI_HEADER_TYPE
] & 0x80) != 0)
200 static int dev_pci_slot(struct udev_device
*dev
, struct netnames
*names
) {
201 struct udev
*udev
= udev_device_get_udev(names
->pcidev
);
202 unsigned domain
, bus
, slot
, func
, dev_port
= 0;
206 struct udev_device
*pci
= NULL
;
207 char slots
[256], str
[256];
208 _cleanup_closedir_
DIR *dir
= NULL
;
210 int hotplug_slot
= 0, err
= 0;
212 if (sscanf(udev_device_get_sysname(names
->pcidev
), "%x:%x:%x.%u", &domain
, &bus
, &slot
, &func
) != 4)
215 /* kernel provided port index for multiple ports on a single PCI function */
216 attr
= udev_device_get_sysattr_value(dev
, "dev_port");
218 dev_port
= strtol(attr
, NULL
, 10);
220 /* compose a name based on the raw kernel's PCI bus, slot numbers */
222 l
= sizeof(names
->pci_path
);
224 l
= strpcpyf(&s
, l
, "P%u", domain
);
225 l
= strpcpyf(&s
, l
, "p%us%u", bus
, slot
);
226 if (func
> 0 || is_pci_multifunction(names
->pcidev
))
227 l
= strpcpyf(&s
, l
, "f%u", func
);
229 l
= strpcpyf(&s
, l
, "d%u", dev_port
);
231 names
->pci_path
[0] = '\0';
233 /* ACPI _SUN — slot user number */
234 pci
= udev_device_new_from_subsystem_sysname(udev
, "subsystem", "pci");
239 xsprintf(slots
, "%s/slots", udev_device_get_syspath(pci
));
240 dir
= opendir(slots
);
246 for (dent
= readdir(dir
); dent
!= NULL
; dent
= readdir(dir
)) {
251 if (dent
->d_name
[0] == '.')
253 i
= strtol(dent
->d_name
, &rest
, 10);
258 xsprintf(str
, "%s/%s/address", slots
, dent
->d_name
);
259 if (read_one_line_file(str
, &address
) >= 0) {
260 /* match slot address with device by stripping the function */
261 if (strneq(address
, udev_device_get_sysname(names
->pcidev
), strlen(address
)))
266 if (hotplug_slot
> 0)
270 if (hotplug_slot
> 0) {
272 l
= sizeof(names
->pci_slot
);
274 l
= strpcpyf(&s
, l
, "P%d", domain
);
275 l
= strpcpyf(&s
, l
, "s%d", hotplug_slot
);
276 if (func
> 0 || is_pci_multifunction(names
->pcidev
))
277 l
= strpcpyf(&s
, l
, "f%d", func
);
279 l
= strpcpyf(&s
, l
, "d%d", dev_port
);
281 names
->pci_slot
[0] = '\0';
284 udev_device_unref(pci
);
288 static int names_pci(struct udev_device
*dev
, struct netnames
*names
) {
289 struct udev_device
*parent
;
294 parent
= udev_device_get_parent(dev
);
296 /* there can only ever be one virtio bus per parent device, so we can
297 safely ignore any virtio buses. see
298 <http://lists.linuxfoundation.org/pipermail/virtualization/2015-August/030331.html> */
299 while (parent
&& streq_ptr("virtio", udev_device_get_subsystem(parent
)))
300 parent
= udev_device_get_parent(parent
);
305 /* check if our direct parent is a PCI device with no other bus in-between */
306 if (streq_ptr("pci", udev_device_get_subsystem(parent
))) {
307 names
->type
= NET_PCI
;
308 names
->pcidev
= parent
;
310 names
->pcidev
= udev_device_get_parent_with_subsystem_devtype(dev
, "pci", NULL
);
314 dev_pci_onboard(dev
, names
);
315 dev_pci_slot(dev
, names
);
319 static int names_usb(struct udev_device
*dev
, struct netnames
*names
) {
320 struct udev_device
*usbdev
;
331 usbdev
= udev_device_get_parent_with_subsystem_devtype(dev
, "usb", "usb_interface");
335 /* get USB port number chain, configuration, interface */
336 strscpy(name
, sizeof(name
), udev_device_get_sysname(usbdev
));
337 s
= strchr(name
, '-');
342 s
= strchr(ports
, ':');
348 s
= strchr(config
, '.');
354 /* prefix every port number in the chain with "u" */
356 while ((s
= strchr(s
, '.')))
358 s
= names
->usb_ports
;
359 l
= strpcpyl(&s
, sizeof(names
->usb_ports
), "u", ports
, NULL
);
361 /* append USB config number, suppress the common config == 1 */
362 if (!streq(config
, "1"))
363 l
= strpcpyl(&s
, sizeof(names
->usb_ports
), "c", config
, NULL
);
365 /* append USB interface number, suppress the interface == 0 */
366 if (!streq(interf
, "0"))
367 l
= strpcpyl(&s
, sizeof(names
->usb_ports
), "i", interf
, NULL
);
369 return -ENAMETOOLONG
;
371 names
->type
= NET_USB
;
375 static int names_bcma(struct udev_device
*dev
, struct netnames
*names
) {
376 struct udev_device
*bcmadev
;
382 bcmadev
= udev_device_get_parent_with_subsystem_devtype(dev
, "bcma", NULL
);
386 /* bus num:core num */
387 if (sscanf(udev_device_get_sysname(bcmadev
), "bcma%*u:%u", &core
) != 1)
389 /* suppress the common core == 0 */
391 xsprintf(names
->bcma_core
, "b%u", core
);
393 names
->type
= NET_BCMA
;
397 static int names_ccw(struct udev_device
*dev
, struct netnames
*names
) {
398 struct udev_device
*cdev
;
406 /* Retrieve the associated CCW device */
407 cdev
= udev_device_get_parent(dev
);
411 /* Network devices are always grouped CCW devices */
412 if (!streq_ptr("ccwgroup", udev_device_get_subsystem(cdev
)))
415 /* Retrieve bus-ID of the grouped CCW device. The bus-ID uniquely
416 * identifies the network device on the Linux on System z channel
417 * subsystem. Note that the bus-ID contains lowercase characters.
419 bus_id
= udev_device_get_sysname(cdev
);
423 /* Check the length of the bus-ID. Rely on that the kernel provides
424 * a correct bus-ID; alternatively, improve this check and parse and
425 * verify each bus-ID part...
427 bus_id_len
= strlen(bus_id
);
428 if (!bus_id_len
|| bus_id_len
< 8 || bus_id_len
> 9)
431 /* Strip leading zeros from the bus id for aesthetic purposes. This
432 * keeps the ccw names stable, yet much shorter in general case of
433 * bus_id 0.0.0600 -> 600. This is similar to e.g. how PCI domain is
434 * not prepended when it is zero.
436 bus_id
+= strspn(bus_id
, ".0");
438 /* Store the CCW bus-ID for use as network device name */
439 rc
= snprintf(names
->ccw_group
, sizeof(names
->ccw_group
), "c%s", bus_id
);
440 if (rc
>= 0 && rc
< (int)sizeof(names
->ccw_group
))
441 names
->type
= NET_CCWGROUP
;
445 static int names_mac(struct udev_device
*dev
, struct netnames
*names
) {
448 unsigned int a1
, a2
, a3
, a4
, a5
, a6
;
450 /* check for NET_ADDR_PERM, skip random MAC addresses */
451 s
= udev_device_get_sysattr_value(dev
, "addr_assign_type");
454 i
= strtoul(s
, NULL
, 0);
458 s
= udev_device_get_sysattr_value(dev
, "address");
461 if (sscanf(s
, "%x:%x:%x:%x:%x:%x", &a1
, &a2
, &a3
, &a4
, &a5
, &a6
) != 6)
464 /* skip empty MAC addresses */
465 if (a1
+ a2
+ a3
+ a4
+ a5
+ a6
== 0)
474 names
->mac_valid
= true;
478 /* IEEE Organizationally Unique Identifier vendor string */
479 static int ieee_oui(struct udev_device
*dev
, struct netnames
*names
, bool test
) {
482 if (!names
->mac_valid
)
484 /* skip commonly misused 00:00:00 (Xerox) prefix */
485 if (memcmp(names
->mac
, "\0\0\0", 3) == 0)
487 xsprintf(str
, "OUI:%02X%02X%02X%02X%02X%02X", names
->mac
[0],
488 names
->mac
[1], names
->mac
[2], names
->mac
[3], names
->mac
[4],
490 udev_builtin_hwdb_lookup(dev
, NULL
, str
, NULL
, test
);
494 static int builtin_net_id(struct udev_device
*dev
, int argc
, char *argv
[], bool test
) {
499 const char *prefix
= "en";
500 struct netnames names
= {};
503 /* handle only ARPHRD_ETHER and ARPHRD_SLIP devices */
504 s
= udev_device_get_sysattr_value(dev
, "type");
507 i
= strtoul(s
, NULL
, 0);
519 /* skip stacked devices, like VLANs, ... */
520 s
= udev_device_get_sysattr_value(dev
, "ifindex");
523 p
= udev_device_get_sysattr_value(dev
, "iflink");
529 devtype
= udev_device_get_devtype(dev
);
531 if (streq("wlan", devtype
))
533 else if (streq("wwan", devtype
))
537 err
= names_mac(dev
, &names
);
538 if (err
>= 0 && names
.mac_valid
) {
541 xsprintf(str
, "%sx%02x%02x%02x%02x%02x%02x", prefix
,
542 names
.mac
[0], names
.mac
[1], names
.mac
[2],
543 names
.mac
[3], names
.mac
[4], names
.mac
[5]);
544 udev_builtin_add_property(dev
, test
, "ID_NET_NAME_MAC", str
);
546 ieee_oui(dev
, &names
, test
);
549 /* get path names for Linux on System z network devices */
550 err
= names_ccw(dev
, &names
);
551 if (err
>= 0 && names
.type
== NET_CCWGROUP
) {
554 if (snprintf(str
, sizeof(str
), "%s%s", prefix
, names
.ccw_group
) < (int)sizeof(str
))
555 udev_builtin_add_property(dev
, test
, "ID_NET_NAME_PATH", str
);
559 /* get PCI based path names, we compose only PCI based paths */
560 err
= names_pci(dev
, &names
);
564 /* plain PCI device */
565 if (names
.type
== NET_PCI
) {
568 if (names
.pci_onboard
[0])
569 if (snprintf(str
, sizeof(str
), "%s%s", prefix
, names
.pci_onboard
) < (int)sizeof(str
))
570 udev_builtin_add_property(dev
, test
, "ID_NET_NAME_ONBOARD", str
);
572 if (names
.pci_onboard_label
)
573 if (snprintf(str
, sizeof(str
), "%s%s", prefix
, names
.pci_onboard_label
) < (int)sizeof(str
))
574 udev_builtin_add_property(dev
, test
, "ID_NET_LABEL_ONBOARD", str
);
576 if (names
.pci_path
[0])
577 if (snprintf(str
, sizeof(str
), "%s%s", prefix
, names
.pci_path
) < (int)sizeof(str
))
578 udev_builtin_add_property(dev
, test
, "ID_NET_NAME_PATH", str
);
580 if (names
.pci_slot
[0])
581 if (snprintf(str
, sizeof(str
), "%s%s", prefix
, names
.pci_slot
) < (int)sizeof(str
))
582 udev_builtin_add_property(dev
, test
, "ID_NET_NAME_SLOT", str
);
587 err
= names_usb(dev
, &names
);
588 if (err
>= 0 && names
.type
== NET_USB
) {
591 if (names
.pci_path
[0])
592 if (snprintf(str
, sizeof(str
), "%s%s%s", prefix
, names
.pci_path
, names
.usb_ports
) < (int)sizeof(str
))
593 udev_builtin_add_property(dev
, test
, "ID_NET_NAME_PATH", str
);
595 if (names
.pci_slot
[0])
596 if (snprintf(str
, sizeof(str
), "%s%s%s", prefix
, names
.pci_slot
, names
.usb_ports
) < (int)sizeof(str
))
597 udev_builtin_add_property(dev
, test
, "ID_NET_NAME_SLOT", str
);
602 err
= names_bcma(dev
, &names
);
603 if (err
>= 0 && names
.type
== NET_BCMA
) {
606 if (names
.pci_path
[0])
607 if (snprintf(str
, sizeof(str
), "%s%s%s", prefix
, names
.pci_path
, names
.bcma_core
) < (int)sizeof(str
))
608 udev_builtin_add_property(dev
, test
, "ID_NET_NAME_PATH", str
);
610 if (names
.pci_slot
[0])
611 if (snprintf(str
, sizeof(str
), "%s%s%s", prefix
, names
.pci_slot
, names
.bcma_core
) < (int)sizeof(str
))
612 udev_builtin_add_property(dev
, test
, "ID_NET_NAME_SLOT", str
);
619 const struct udev_builtin udev_builtin_net_id
= {
621 .cmd
= builtin_net_id
,
622 .help
= "Network device properties",