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<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
  41  *
  42  * All multi-function PCI devices will carry the [f<function>] number in the
  43  * device name, including the function 0 device.
  44  *
  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
  47  * exported.
  48  * The usual USB configuration == 1 and interface == 0 values are suppressed.
  49  *
  50  * PCI ethernet card with firmware index "1":
  51  *   ID_NET_NAME_ONBOARD=eno1
  52  *   ID_NET_NAME_ONBOARD_LABEL=Ethernet Port 1
  53  *
  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
  59  *
  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
  67  *
  68  * PCI wlan card:
  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
  72  *
  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
  77  *
  78  * USB Android phone:
  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
  82  */
  83
  84 #include <stdio.h>
  85 #include <stdlib.h>
  86 #include <stdarg.h>
  87 #include <unistd.h>
  88 #include <string.h>
  89 #include <errno.h>
  90 #include <net/if.h>
  91 #include <linux/pci_regs.h>
  92
  93 #include "udev.h"
  94
  95 enum netname_type{
  96         NET_UNDEF,
  97         NET_PCI,
  98         NET_USB,
  99         NET_BCMA,
 100 };
 101
 102 struct netnames {
 103         enum netname_type type;
 104
 105         uint8_t mac[6];
 106         bool mac_valid;
 107
 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;
 113
 114         char usb_ports[IFNAMSIZ];
 115
 116         char bcma_core[IFNAMSIZ];
 117 };
 118
 119 /* retrieve on-board index number and label from firmware */
 120 static int dev_pci_onboard(struct udev_device *dev, struct netnames *names) {
 121         const char *index;
 122         int idx;
 123
 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 */
 127         if (!index)
 128                 index = udev_device_get_sysattr_value(names->pcidev, "index");
 129         if (!index)
 130                 return -ENOENT;
 131         idx = strtoul(index, NULL, 0);
 132         if (idx <= 0)
 133                 return -EINVAL;
 134         snprintf(names->pci_onboard, sizeof(names->pci_onboard), "o%d", idx);
 135
 136         names->pci_onboard_label = udev_device_get_sysattr_value(names->pcidev, "label");
 137         return 0;
 138 }
 139
 140 /* read the 256 bytes PCI configuration space to check the multi-function bit */
 141 static bool is_pci_multifunction(struct udev_device *dev) {
 142         char filename[256];
 143         FILE *f = NULL;
 144         char config[64];
 145         bool multi = false;
 146
 147         snprintf(filename, sizeof(filename), "%s/config", udev_device_get_syspath(dev));
 148         f = fopen(filename, "re");
 149         if (!f)
 150                 goto out;
 151         if (fread(&config, sizeof(config), 1, f) != 1)
 152                 goto out;
 153
 154         /* bit 0-6 header type, bit 7 multi/single function device */
 155         if ((config[PCI_HEADER_TYPE] & 0x80) != 0)
 156                 multi = true;
 157 out:
 158         if(f)
 159                 fclose(f);
 160         return multi;
 161 }
 162
 163 static int dev_pci_slot(struct udev_device *dev, struct netnames *names) {
 164         struct udev *udev = udev_device_get_udev(names->pcidev);
 165         unsigned int bus;
 166         unsigned int slot;
 167         unsigned int func;
 168         unsigned int dev_id = 0;
 169         size_t l;
 170         char *s;
 171         const char *attr;
 172         struct udev_device *pci = NULL;
 173         char slots[256];
 174         DIR *dir;
 175         struct dirent *dent;
 176         char str[256];
 177         int hotplug_slot = 0;
 178         int err = 0;
 179
 180         if (sscanf(udev_device_get_sysname(names->pcidev), "0000:%x:%x.%d", &bus, &slot, &func) != 3)
 181                 return -ENOENT;
 182
 183         /* kernel provided multi-device index */
 184         attr = udev_device_get_sysattr_value(dev, "dev_id");
 185         if (attr)
 186                 dev_id = strtol(attr, NULL, 16);
 187
 188         /* compose a name based on the raw kernel's PCI bus, slot numbers */
 189         s = names->pci_path;
 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);
 193         if (dev_id > 0)
 194                 l = strpcpyf(&s, l, "d%d", dev_id);
 195         if (l == 0)
 196                 names->pci_path[0] = '\0';
 197
 198         /* ACPI _SUN  -- slot user number */
 199         pci = udev_device_new_from_subsystem_sysname(udev, "subsystem", "pci");
 200         if (!pci) {
 201                 err = -ENOENT;
 202                 goto out;
 203         }
 204         snprintf(slots, sizeof(slots), "%s/slots", udev_device_get_syspath(pci));
 205         dir = opendir(slots);
 206         if (!dir) {
 207                 err = -errno;
 208                 goto out;
 209         }
 210
 211         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 212                 int i;
 213                 char *rest;
 214                 char *address;
 215
 216                 if (dent->d_name[0] == '.')
 217                         continue;
 218                 i = strtol(dent->d_name, &rest, 10);
 219                 if (rest[0] != '\0')
 220                         continue;
 221                 if (i < 1)
 222                         continue;
 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)
 227                                 hotplug_slot = i;
 228                         free(address);
 229                 }
 230
 231                 if (hotplug_slot > 0)
 232                         break;
 233         }
 234         closedir(dir);
 235
 236         if (hotplug_slot > 0) {
 237                 s = names->pci_slot;
 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);
 241                 if (dev_id > 0)
 242                         l = strpcpyf(&s, l, "d%d", dev_id);
 243                 if (l == 0)
 244                         names->pci_path[0] = '\0';
 245         }
 246 out:
 247         udev_device_unref(pci);
 248         return err;
 249 }
 250
 251 static int names_pci(struct udev_device *dev, struct netnames *names) {
 252         struct udev_device *parent;
 253
 254         parent = udev_device_get_parent(dev);
 255         if (!parent)
 256                 return -ENOENT;
 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;
 261         } else {
 262                 names->pcidev = udev_device_get_parent_with_subsystem_devtype(dev, "pci", NULL);
 263                 if (!names->pcidev)
 264                         return -ENOENT;
 265         }
 266         dev_pci_onboard(dev, names);
 267         dev_pci_slot(dev, names);
 268         return 0;
 269 }
 270
 271 static int names_usb(struct udev_device *dev, struct netnames *names) {
 272         struct udev_device *usbdev;
 273         char name[256];
 274         char *ports;
 275         char *config;
 276         char *interf;
 277         size_t l;
 278         char *s;
 279
 280         usbdev = udev_device_get_parent_with_subsystem_devtype(dev, "usb", "usb_interface");
 281         if (!usbdev)
 282                 return -ENOENT;
 283
 284         /* get USB port number chain, configuration, interface */
 285         strscpy(name, sizeof(name), udev_device_get_sysname(usbdev));
 286         s = strchr(name, '-');
 287         if (!s)
 288                 return -EINVAL;
 289         ports = s+1;
 290
 291         s = strchr(ports, ':');
 292         if (!s)
 293                 return -EINVAL;
 294         s[0] = '\0';
 295         config = s+1;
 296
 297         s = strchr(config, '.');
 298         if (!s)
 299                 return -EINVAL;
 300         s[0] = '\0';
 301         interf = s+1;
 302
 303         /* prefix every port number in the chain with "u"*/
 304         s = ports;
 305         while ((s = strchr(s, '.')))
 306                 s[0] = 'u';
 307         s = names->usb_ports;
 308         l = strpcpyl(&s, sizeof(names->usb_ports), "u", ports, NULL);
 309
 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);
 313
 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);
 317         if (l == 0)
 318                 return -ENAMETOOLONG;
 319
 320         names->type = NET_USB;
 321         return 0;
 322 }
 323
 324 static int names_bcma(struct udev_device *dev, struct netnames *names) {
 325         struct udev_device *bcmadev;
 326         unsigned int core;
 327
 328         bcmadev = udev_device_get_parent_with_subsystem_devtype(dev, "bcma", NULL);
 329         if (!bcmadev)
 330                 return -ENOENT;
 331
 332         /* bus num:core num */
 333         if (sscanf(udev_device_get_sysname(bcmadev), "bcma%*d:%d", &core) != 1)
 334                 return -EINVAL;
 335         /* suppress the common core == 0 */
 336         if (core > 0)
 337                 snprintf(names->bcma_core, sizeof(names->bcma_core), "b%d", core);
 338
 339         names->type = NET_BCMA;
 340         return 0;
 341 }
 342
 343 static int names_mac(struct udev_device *dev, struct netnames *names) {
 344         const char *s;
 345         unsigned int i;
 346         unsigned int a1, a2, a3, a4, a5, a6;
 347
 348         /* check for NET_ADDR_PERM, skip random MAC addresses */
 349         s = udev_device_get_sysattr_value(dev, "addr_assign_type");
 350         if (!s)
 351                 return EXIT_FAILURE;
 352         i = strtoul(s, NULL, 0);
 353         if (i != 0)
 354                 return 0;
 355
 356         s = udev_device_get_sysattr_value(dev, "address");
 357         if (!s)
 358                 return -ENOENT;
 359         if (sscanf(s, "%x:%x:%x:%x:%x:%x", &a1, &a2, &a3, &a4, &a5, &a6) != 6)
 360                 return -EINVAL;
 361
 362         /* skip empty MAC addresses */
 363         if (a1 + a2 + a3 + a4 + a5 + a6 == 0)
 364                 return -EINVAL;
 365
 366         names->mac[0] = a1;
 367         names->mac[1] = a2;
 368         names->mac[2] = a3;
 369         names->mac[3] = a4;
 370         names->mac[4] = a5;
 371         names->mac[5] = a6;
 372         names->mac_valid = true;
 373         return 0;
 374 }
 375
 376 /* IEEE Organizationally Unique Identifier vendor string */
 377 static int ieee_oui(struct udev_device *dev, struct netnames *names, bool test) {
 378         char str[32];
 379
 380         if (!names->mac_valid)
 381                 return -ENOENT;
 382         /* skip commonly misused 00:00:00 (Xerox) prefix */
 383         if (memcmp(names->mac, "\0\0\0", 3) == 0)
 384                 return -EINVAL;
 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);
 389         return 0;
 390 }
 391
 392 static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool test) {
 393         const char *s;
 394         const char *p;
 395         unsigned int i;
 396         const char *devtype;
 397         const char *prefix = "en";
 398         struct netnames names;
 399         int err;
 400
 401         /* handle only ARPHRD_ETHER devices */
 402         s = udev_device_get_sysattr_value(dev, "type");
 403         if (!s)
 404                 return EXIT_FAILURE;
 405         i = strtoul(s, NULL, 0);
 406         if (i != 1)
 407                 return 0;
 408
 409         /* skip stacked devices, like VLANs, ... */
 410         s = udev_device_get_sysattr_value(dev, "ifindex");
 411         if (!s)
 412                 return EXIT_FAILURE;
 413         p = udev_device_get_sysattr_value(dev, "iflink");
 414         if (!p)
 415                 return EXIT_FAILURE;
 416         if (strcmp(s, p) != 0)
 417                 return 0;
 418
 419         devtype = udev_device_get_devtype(dev);
 420         if (devtype) {
 421                 if (streq("wlan", devtype))
 422                         prefix = "wl";
 423                 else if (streq("wwan", devtype))
 424                         prefix = "ww";
 425         }
 426
 427         zero(names);
 428         err = names_mac(dev, &names);
 429         if (err >= 0 && names.mac_valid) {
 430                 char str[IFNAMSIZ];
 431
 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);
 436
 437                 ieee_oui(dev, &names, test);
 438         }
 439
 440         /* get PCI based path names, we compose only PCI based paths */
 441         err = names_pci(dev, &names);
 442         if (err < 0)
 443                 goto out;
 444
 445         /* plain PCI device */
 446         if (names.type == NET_PCI) {
 447                 char str[IFNAMSIZ];
 448
 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);
 452
 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);
 456
 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);
 460
 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);
 464                 goto out;
 465         }
 466
 467         /* USB device */
 468         err = names_usb(dev, &names);
 469         if (err >= 0 && names.type == NET_USB) {
 470                 char str[IFNAMSIZ];
 471
 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);
 475
 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);
 479                 goto out;
 480         }
 481
 482         /* Broadcom bus */
 483         err = names_bcma(dev, &names);
 484         if (err >= 0 && names.type == NET_BCMA) {
 485                 char str[IFNAMSIZ];
 486
 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);
 490
 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);
 494                 goto out;
 495         }
 496
 497 out:
 498         return EXIT_SUCCESS;
 499 }
 500
 501 const struct udev_builtin udev_builtin_net_id = {
 502         .name = "net_id",
 503         .cmd = builtin_net_id,
 504         .help = "network device properties",
 505 };