src/udev/udev-builtin-net_id.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2012 Kay Sievers <kay@vrfy.org>
   5
   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.
  10
  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.
  15
  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/>.
  18 ***/
  19
  20 /*
  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
  26  *
  27  * http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames
  28  *
  29  * Two character prefixes based on the type of interface:
  30  *   en -- ethernet
  31  *   wl -- wlan
  32  *   ww -- wwan
  33  *
  34  * Type of names:
  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<domain>]p<bus>s<slot>[f<function>][d<dev_id>]
  39  *                                         -- PCI geographical location
  40  *   [P<domain>]p<bus>s<slot>[f<function>][u<port>][..][c<config>][i<interface>]
  41  *                                         -- USB port number chain
  42  *
  43  * All multi-function PCI devices will carry the [f<function>] number in the
  44  * device name, including the function 0 device.
  45  *
  46  * When using PCI geography, The PCI domain is only prepended when it is not 0.
  47  *
  48  * For USB devices the full chain of port numbers of hubs is composed. If the
  49  * name gets longer than the maximum number of 15 characters, the name is not
  50  * exported.
  51  * The usual USB configuration == 1 and interface == 0 values are suppressed.
  52  *
  53  * PCI ethernet card with firmware index "1":
  54  *   ID_NET_NAME_ONBOARD=eno1
  55  *   ID_NET_NAME_ONBOARD_LABEL=Ethernet Port 1
  56  *
  57  * PCI ethernet card in hotplug slot with firmware index number:
  58  *   /sys/devices/pci0000:00/0000:00:1c.3/0000:05:00.0/net/ens1
  59  *   ID_NET_NAME_MAC=enx000000000466
  60  *   ID_NET_NAME_PATH=enp5s0
  61  *   ID_NET_NAME_SLOT=ens1
  62  *
  63  * PCI ethernet multi-function card with 2 ports:
  64  *   /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.0/net/enp2s0f0
  65  *   ID_NET_NAME_MAC=enx78e7d1ea46da
  66  *   ID_NET_NAME_PATH=enp2s0f0
  67  *   /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.1/net/enp2s0f1
  68  *   ID_NET_NAME_MAC=enx78e7d1ea46dc
  69  *   ID_NET_NAME_PATH=enp2s0f1
  70  *
  71  * PCI wlan card:
  72  *   /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlp3s0
  73  *   ID_NET_NAME_MAC=wlx0024d7e31130
  74  *   ID_NET_NAME_PATH=wlp3s0
  75  *
  76  * USB built-in 3G modem:
  77  *   /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.6/net/wwp0s29u1u4i6
  78  *   ID_NET_NAME_MAC=wwx028037ec0200
  79  *   ID_NET_NAME_PATH=wwp0s29u1u4i6
  80  *
  81  * USB Android phone:
  82  *   /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/net/enp0s29u1u2
  83  *   ID_NET_NAME_MAC=enxd626b3450fb5
  84  *   ID_NET_NAME_PATH=enp0s29u1u2
  85  */
  86
  87 #include <stdio.h>
  88 #include <stdlib.h>
  89 #include <stdarg.h>
  90 #include <unistd.h>
  91 #include <string.h>
  92 #include <errno.h>
  93 #include <net/if.h>
  94 #include <linux/pci_regs.h>
  95
  96 #include "udev.h"
  97 #include "fileio.h"
  98
  99 enum netname_type{
 100         NET_UNDEF,
 101         NET_PCI,
 102         NET_USB,
 103         NET_BCMA,
 104         NET_VIRTIO,
 105 };
 106
 107 struct netnames {
 108         enum netname_type type;
 109
 110         uint8_t mac[6];
 111         bool mac_valid;
 112
 113         struct udev_device *pcidev;
 114         char pci_slot[IFNAMSIZ];
 115         char pci_path[IFNAMSIZ];
 116         char pci_onboard[IFNAMSIZ];
 117         const char *pci_onboard_label;
 118
 119         char usb_ports[IFNAMSIZ];
 120
 121         char bcma_core[IFNAMSIZ];
 122
 123         char virtio_core[IFNAMSIZ];
 124 };
 125
 126 /* retrieve on-board index number and label from firmware */
 127 static int dev_pci_onboard(struct udev_device *dev, struct netnames *names) {
 128         const char *index;
 129         int idx;
 130
 131         /* ACPI _DSM  -- device specific method for naming a PCI or PCI Express device */
 132         index = udev_device_get_sysattr_value(names->pcidev, "acpi_index");
 133         /* SMBIOS type 41 -- Onboard Devices Extended Information */
 134         if (!index)
 135                 index = udev_device_get_sysattr_value(names->pcidev, "index");
 136         if (!index)
 137                 return -ENOENT;
 138         idx = strtoul(index, NULL, 0);
 139         if (idx <= 0)
 140                 return -EINVAL;
 141         snprintf(names->pci_onboard, sizeof(names->pci_onboard), "o%d", idx);
 142
 143         names->pci_onboard_label = udev_device_get_sysattr_value(names->pcidev, "label");
 144         return 0;
 145 }
 146
 147 /* read the 256 bytes PCI configuration space to check the multi-function bit */
 148 static bool is_pci_multifunction(struct udev_device *dev) {
 149         char filename[256];
 150         FILE *f = NULL;
 151         char config[64];
 152         bool multi = false;
 153
 154         snprintf(filename, sizeof(filename), "%s/config", udev_device_get_syspath(dev));
 155         f = fopen(filename, "re");
 156         if (!f)
 157                 goto out;
 158         if (fread(&config, sizeof(config), 1, f) != 1)
 159                 goto out;
 160
 161         /* bit 0-6 header type, bit 7 multi/single function device */
 162         if ((config[PCI_HEADER_TYPE] & 0x80) != 0)
 163                 multi = true;
 164 out:
 165         if (f)
 166                 fclose(f);
 167         return multi;
 168 }
 169
 170 static int dev_pci_slot(struct udev_device *dev, struct netnames *names) {
 171         struct udev *udev = udev_device_get_udev(names->pcidev);
 172         unsigned domain, bus, slot, func, dev_id = 0;
 173         size_t l;
 174         char *s;
 175         const char *attr;
 176         struct udev_device *pci = NULL;
 177         char slots[256], str[256];
 178         _cleanup_closedir_ DIR *dir = NULL;
 179         struct dirent *dent;
 180         int hotplug_slot = 0, err = 0;
 181
 182         if (sscanf(udev_device_get_sysname(names->pcidev), "%x:%x:%x.%u", &domain, &bus, &slot, &func) != 4)
 183                 return -ENOENT;
 184
 185         /* kernel provided multi-device index */
 186         attr = udev_device_get_sysattr_value(dev, "dev_id");
 187         if (attr)
 188                 dev_id = strtol(attr, NULL, 16);
 189
 190         /* compose a name based on the raw kernel's PCI bus, slot numbers */
 191         s = names->pci_path;
 192         l = sizeof(names->pci_path);
 193         if (domain > 0)
 194                 l = strpcpyf(&s, l, "P%d", domain);
 195         l = strpcpyf(&s, l, "p%ds%d", bus, slot);
 196         if (func > 0 || is_pci_multifunction(names->pcidev))
 197                 l = strpcpyf(&s, l, "f%d", func);
 198         if (dev_id > 0)
 199                 l = strpcpyf(&s, l, "d%d", dev_id);
 200         if (l == 0)
 201                 names->pci_path[0] = '\0';
 202
 203         /* ACPI _SUN  -- slot user number */
 204         pci = udev_device_new_from_subsystem_sysname(udev, "subsystem", "pci");
 205         if (!pci) {
 206                 err = -ENOENT;
 207                 goto out;
 208         }
 209         snprintf(slots, sizeof(slots), "%s/slots", udev_device_get_syspath(pci));
 210         dir = opendir(slots);
 211         if (!dir) {
 212                 err = -errno;
 213                 goto out;
 214         }
 215
 216         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 217                 int i;
 218                 char *rest;
 219                 char *address;
 220
 221                 if (dent->d_name[0] == '.')
 222                         continue;
 223                 i = strtol(dent->d_name, &rest, 10);
 224                 if (rest[0] != '\0')
 225                         continue;
 226                 if (i < 1)
 227                         continue;
 228                 snprintf(str, sizeof(str), "%s/%s/address", slots, dent->d_name);
 229                 if (read_one_line_file(str, &address) >= 0) {
 230                         /* match slot address with device by stripping the function */
 231                         if (strneq(address, udev_device_get_sysname(names->pcidev), strlen(address)))
 232                                 hotplug_slot = i;
 233                         free(address);
 234                 }
 235
 236                 if (hotplug_slot > 0)
 237                         break;
 238         }
 239
 240         if (hotplug_slot > 0) {
 241                 s = names->pci_slot;
 242                 l = sizeof(names->pci_slot);
 243                 if (domain > 0)
 244                         l = strpcpyf(&s, l, "P%d", domain);
 245                 l = strpcpyf(&s, l, "s%d", hotplug_slot);
 246                 if (func > 0 || is_pci_multifunction(names->pcidev))
 247                         l = strpcpyf(&s, l, "f%d", func);
 248                 if (dev_id > 0)
 249                         l = strpcpyf(&s, l, "d%d", dev_id);
 250                 if (l == 0)
 251                         names->pci_path[0] = '\0';
 252         }
 253 out:
 254         udev_device_unref(pci);
 255         return err;
 256 }
 257
 258 static int names_pci(struct udev_device *dev, struct netnames *names) {
 259         struct udev_device *parent;
 260
 261         parent = udev_device_get_parent(dev);
 262         if (!parent)
 263                 return -ENOENT;
 264         /* check if our direct parent is a PCI device with no other bus in-between */
 265         if (streq_ptr("pci", udev_device_get_subsystem(parent))) {
 266                 names->type = NET_PCI;
 267                 names->pcidev = parent;
 268         } else {
 269                 names->pcidev = udev_device_get_parent_with_subsystem_devtype(dev, "pci", NULL);
 270                 if (!names->pcidev)
 271                         return -ENOENT;
 272         }
 273         dev_pci_onboard(dev, names);
 274         dev_pci_slot(dev, names);
 275         return 0;
 276 }
 277
 278 static int names_usb(struct udev_device *dev, struct netnames *names) {
 279         struct udev_device *usbdev;
 280         char name[256];
 281         char *ports;
 282         char *config;
 283         char *interf;
 284         size_t l;
 285         char *s;
 286
 287         usbdev = udev_device_get_parent_with_subsystem_devtype(dev, "usb", "usb_interface");
 288         if (!usbdev)
 289                 return -ENOENT;
 290
 291         /* get USB port number chain, configuration, interface */
 292         strscpy(name, sizeof(name), udev_device_get_sysname(usbdev));
 293         s = strchr(name, '-');
 294         if (!s)
 295                 return -EINVAL;
 296         ports = s+1;
 297
 298         s = strchr(ports, ':');
 299         if (!s)
 300                 return -EINVAL;
 301         s[0] = '\0';
 302         config = s+1;
 303
 304         s = strchr(config, '.');
 305         if (!s)
 306                 return -EINVAL;
 307         s[0] = '\0';
 308         interf = s+1;
 309
 310         /* prefix every port number in the chain with "u"*/
 311         s = ports;
 312         while ((s = strchr(s, '.')))
 313                 s[0] = 'u';
 314         s = names->usb_ports;
 315         l = strpcpyl(&s, sizeof(names->usb_ports), "u", ports, NULL);
 316
 317         /* append USB config number, suppress the common config == 1 */
 318         if (!streq(config, "1"))
 319                 l = strpcpyl(&s, sizeof(names->usb_ports), "c", config, NULL);
 320
 321         /* append USB interface number, suppress the interface == 0 */
 322         if (!streq(interf, "0"))
 323                 l = strpcpyl(&s, sizeof(names->usb_ports), "i", interf, NULL);
 324         if (l == 0)
 325                 return -ENAMETOOLONG;
 326
 327         names->type = NET_USB;
 328         return 0;
 329 }
 330
 331 static int names_bcma(struct udev_device *dev, struct netnames *names) {
 332         struct udev_device *bcmadev;
 333         unsigned int core;
 334
 335         bcmadev = udev_device_get_parent_with_subsystem_devtype(dev, "bcma", NULL);
 336         if (!bcmadev)
 337                 return -ENOENT;
 338
 339         /* bus num:core num */
 340         if (sscanf(udev_device_get_sysname(bcmadev), "bcma%*u:%u", &core) != 1)
 341                 return -EINVAL;
 342         /* suppress the common core == 0 */
 343         if (core > 0)
 344                 snprintf(names->bcma_core, sizeof(names->bcma_core), "b%u", core);
 345
 346         names->type = NET_BCMA;
 347         return 0;
 348 }
 349
 350 static int names_virtio(struct udev_device *dev, struct netnames *names) {
 351         struct udev_device *virtdev;
 352         unsigned int core;
 353
 354         virtdev = udev_device_get_parent_with_subsystem_devtype(dev, "virtio", NULL);
 355         if (!virtdev)
 356                 return -ENOENT;
 357
 358         /* core num */
 359         if (sscanf(udev_device_get_sysname(virtdev), "virtio%u", &core) != 1)
 360                 return -EINVAL;
 361         /* suppress the common core == 0 */
 362         if (core > 0)
 363                 snprintf(names->virtio_core, sizeof(names->virtio_core), "v%u", core);
 364
 365         names->type = NET_VIRTIO;
 366         return 0;
 367 }
 368
 369 static int names_mac(struct udev_device *dev, struct netnames *names) {
 370         const char *s;
 371         unsigned int i;
 372         unsigned int a1, a2, a3, a4, a5, a6;
 373
 374         /* check for NET_ADDR_PERM, skip random MAC addresses */
 375         s = udev_device_get_sysattr_value(dev, "addr_assign_type");
 376         if (!s)
 377                 return EXIT_FAILURE;
 378         i = strtoul(s, NULL, 0);
 379         if (i != 0)
 380                 return 0;
 381
 382         s = udev_device_get_sysattr_value(dev, "address");
 383         if (!s)
 384                 return -ENOENT;
 385         if (sscanf(s, "%x:%x:%x:%x:%x:%x", &a1, &a2, &a3, &a4, &a5, &a6) != 6)
 386                 return -EINVAL;
 387
 388         /* skip empty MAC addresses */
 389         if (a1 + a2 + a3 + a4 + a5 + a6 == 0)
 390                 return -EINVAL;
 391
 392         names->mac[0] = a1;
 393         names->mac[1] = a2;
 394         names->mac[2] = a3;
 395         names->mac[3] = a4;
 396         names->mac[4] = a5;
 397         names->mac[5] = a6;
 398         names->mac_valid = true;
 399         return 0;
 400 }
 401
 402 /* IEEE Organizationally Unique Identifier vendor string */
 403 static int ieee_oui(struct udev_device *dev, struct netnames *names, bool test) {
 404         char str[32];
 405
 406         if (!names->mac_valid)
 407                 return -ENOENT;
 408         /* skip commonly misused 00:00:00 (Xerox) prefix */
 409         if (memcmp(names->mac, "\0\0\0", 3) == 0)
 410                 return -EINVAL;
 411         snprintf(str, sizeof(str), "OUI:%02X%02X%02X%02X%02X%02X",
 412                  names->mac[0], names->mac[1], names->mac[2],
 413                  names->mac[3], names->mac[4], names->mac[5]);
 414         udev_builtin_hwdb_lookup(dev, NULL, str, NULL, test);
 415         return 0;
 416 }
 417
 418 static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool test) {
 419         const char *s;
 420         const char *p;
 421         unsigned int i;
 422         const char *devtype;
 423         const char *prefix = "en";
 424         struct netnames names = {};
 425         int err;
 426
 427         /* handle only ARPHRD_ETHER devices */
 428         s = udev_device_get_sysattr_value(dev, "type");
 429         if (!s)
 430                 return EXIT_FAILURE;
 431         i = strtoul(s, NULL, 0);
 432         if (i != 1)
 433                 return 0;
 434
 435         /* skip stacked devices, like VLANs, ... */
 436         s = udev_device_get_sysattr_value(dev, "ifindex");
 437         if (!s)
 438                 return EXIT_FAILURE;
 439         p = udev_device_get_sysattr_value(dev, "iflink");
 440         if (!p)
 441                 return EXIT_FAILURE;
 442         if (!streq(s, p))
 443                 return 0;
 444
 445         devtype = udev_device_get_devtype(dev);
 446         if (devtype) {
 447                 if (streq("wlan", devtype))
 448                         prefix = "wl";
 449                 else if (streq("wwan", devtype))
 450                         prefix = "ww";
 451         }
 452
 453         err = names_mac(dev, &names);
 454         if (err >= 0 && names.mac_valid) {
 455                 char str[IFNAMSIZ];
 456
 457                 snprintf(str, sizeof(str), "%sx%02x%02x%02x%02x%02x%02x", prefix,
 458                          names.mac[0], names.mac[1], names.mac[2],
 459                          names.mac[3], names.mac[4], names.mac[5]);
 460                 udev_builtin_add_property(dev, test, "ID_NET_NAME_MAC", str);
 461
 462                 ieee_oui(dev, &names, test);
 463         }
 464
 465         /* get PCI based path names, we compose only PCI based paths */
 466         err = names_pci(dev, &names);
 467         if (err < 0)
 468                 goto out;
 469
 470         /* plain PCI device */
 471         if (names.type == NET_PCI) {
 472                 char str[IFNAMSIZ];
 473
 474                 if (names.pci_onboard[0])
 475                         if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard) < (int)sizeof(str))
 476                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_ONBOARD", str);
 477
 478                 if (names.pci_onboard_label)
 479                         if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard_label) < (int)sizeof(str))
 480                                 udev_builtin_add_property(dev, test, "ID_NET_LABEL_ONBOARD", str);
 481
 482                 if (names.pci_path[0])
 483                         if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_path) < (int)sizeof(str))
 484                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
 485
 486                 if (names.pci_slot[0])
 487                         if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_slot) < (int)sizeof(str))
 488                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
 489                 goto out;
 490         }
 491
 492         /* USB device */
 493         err = names_usb(dev, &names);
 494         if (err >= 0 && names.type == NET_USB) {
 495                 char str[IFNAMSIZ];
 496
 497                 if (names.pci_path[0])
 498                         if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.usb_ports) < (int)sizeof(str))
 499                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
 500
 501                 if (names.pci_slot[0])
 502                         if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.usb_ports) < (int)sizeof(str))
 503                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
 504                 goto out;
 505         }
 506
 507         /* Broadcom bus */
 508         err = names_bcma(dev, &names);
 509         if (err >= 0 && names.type == NET_BCMA) {
 510                 char str[IFNAMSIZ];
 511
 512                 if (names.pci_path[0])
 513                         if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.bcma_core) < (int)sizeof(str))
 514                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
 515
 516                 if (names.pci_slot[0])
 517                         if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.bcma_core) < (int)sizeof(str))
 518                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
 519                 goto out;
 520         }
 521
 522         /* virtio bus */
 523         err = names_virtio(dev, &names);
 524         if (err >= 0 && names.type == NET_VIRTIO) {
 525                 char str[IFNAMSIZ];
 526
 527                 if (names.pci_path[0])
 528                         if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.virtio_core) < (int)sizeof(str))
 529                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
 530
 531                 if (names.pci_slot[0])
 532                         if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.virtio_core) < (int)sizeof(str))
 533                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
 534                 goto out;
 535         }
 536
 537 out:
 538         return EXIT_SUCCESS;
 539 }
 540
 541 const struct udev_builtin udev_builtin_net_id = {
 542         .name = "net_id",
 543         .cmd = builtin_net_id,
 544         .help = "network device properties",
 545 };