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 };
 105
 106 struct netnames {
 107         enum netname_type type;
 108
 109         uint8_t mac[6];
 110         bool mac_valid;
 111
 112         struct udev_device *pcidev;
 113         char pci_slot[IFNAMSIZ];
 114         char pci_path[IFNAMSIZ];
 115         char pci_onboard[IFNAMSIZ];
 116         const char *pci_onboard_label;
 117
 118         char usb_ports[IFNAMSIZ];
 119
 120         char bcma_core[IFNAMSIZ];
 121 };
 122
 123 /* retrieve on-board index number and label from firmware */
 124 static int dev_pci_onboard(struct udev_device *dev, struct netnames *names) {
 125         const char *index;
 126         int idx;
 127
 128         /* ACPI _DSM  -- device specific method for naming a PCI or PCI Express device */
 129         index = udev_device_get_sysattr_value(names->pcidev, "acpi_index");
 130         /* SMBIOS type 41 -- Onboard Devices Extended Information */
 131         if (!index)
 132                 index = udev_device_get_sysattr_value(names->pcidev, "index");
 133         if (!index)
 134                 return -ENOENT;
 135         idx = strtoul(index, NULL, 0);
 136         if (idx <= 0)
 137                 return -EINVAL;
 138         snprintf(names->pci_onboard, sizeof(names->pci_onboard), "o%d", idx);
 139
 140         names->pci_onboard_label = udev_device_get_sysattr_value(names->pcidev, "label");
 141         return 0;
 142 }
 143
 144 /* read the 256 bytes PCI configuration space to check the multi-function bit */
 145 static bool is_pci_multifunction(struct udev_device *dev) {
 146         char filename[256];
 147         FILE *f = NULL;
 148         char config[64];
 149         bool multi = false;
 150
 151         snprintf(filename, sizeof(filename), "%s/config", udev_device_get_syspath(dev));
 152         f = fopen(filename, "re");
 153         if (!f)
 154                 goto out;
 155         if (fread(&config, sizeof(config), 1, f) != 1)
 156                 goto out;
 157
 158         /* bit 0-6 header type, bit 7 multi/single function device */
 159         if ((config[PCI_HEADER_TYPE] & 0x80) != 0)
 160                 multi = true;
 161 out:
 162         if (f)
 163                 fclose(f);
 164         return multi;
 165 }
 166
 167 static int dev_pci_slot(struct udev_device *dev, struct netnames *names) {
 168         struct udev *udev = udev_device_get_udev(names->pcidev);
 169         unsigned domain, bus, slot, func, dev_id = 0;
 170         size_t l;
 171         char *s;
 172         const char *attr;
 173         struct udev_device *pci = NULL;
 174         char slots[256], str[256];
 175         _cleanup_closedir_ DIR *dir = NULL;
 176         struct dirent *dent;
 177         int hotplug_slot = 0, err = 0;
 178
 179         if (sscanf(udev_device_get_sysname(names->pcidev), "%x:%x:%x.%u", &domain, &bus, &slot, &func) != 4)
 180                 return -ENOENT;
 181
 182         /* kernel provided multi-device index */
 183         attr = udev_device_get_sysattr_value(dev, "dev_id");
 184         if (attr)
 185                 dev_id = strtol(attr, NULL, 16);
 186
 187         /* compose a name based on the raw kernel's PCI bus, slot numbers */
 188         s = names->pci_path;
 189         l = sizeof(names->pci_path);
 190         if (domain > 0)
 191                 l = strpcpyf(&s, l, "P%d", domain);
 192         l = strpcpyf(&s, l, "p%ds%d", bus, slot);
 193         if (func > 0 || is_pci_multifunction(names->pcidev))
 194                 l = strpcpyf(&s, l, "f%d", func);
 195         if (dev_id > 0)
 196                 l = strpcpyf(&s, l, "d%d", dev_id);
 197         if (l == 0)
 198                 names->pci_path[0] = '\0';
 199
 200         /* ACPI _SUN  -- slot user number */
 201         pci = udev_device_new_from_subsystem_sysname(udev, "subsystem", "pci");
 202         if (!pci) {
 203                 err = -ENOENT;
 204                 goto out;
 205         }
 206         snprintf(slots, sizeof(slots), "%s/slots", udev_device_get_syspath(pci));
 207         dir = opendir(slots);
 208         if (!dir) {
 209                 err = -errno;
 210                 goto out;
 211         }
 212
 213         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 214                 int i;
 215                 char *rest;
 216                 char *address;
 217
 218                 if (dent->d_name[0] == '.')
 219                         continue;
 220                 i = strtol(dent->d_name, &rest, 10);
 221                 if (rest[0] != '\0')
 222                         continue;
 223                 if (i < 1)
 224                         continue;
 225                 snprintf(str, sizeof(str), "%s/%s/address", slots, dent->d_name);
 226                 if (read_one_line_file(str, &address) >= 0) {
 227                         /* match slot address with device by stripping the function */
 228                         if (strneq(address, udev_device_get_sysname(names->pcidev), strlen(address)))
 229                                 hotplug_slot = i;
 230                         free(address);
 231                 }
 232
 233                 if (hotplug_slot > 0)
 234                         break;
 235         }
 236
 237         if (hotplug_slot > 0) {
 238                 s = names->pci_slot;
 239                 l = sizeof(names->pci_slot);
 240                 if (domain > 0)
 241                         l = strpcpyf(&s, l, "P%d", domain);
 242                 l = strpcpyf(&s, l, "s%d", hotplug_slot);
 243                 if (func > 0 || is_pci_multifunction(names->pcidev))
 244                         l = strpcpyf(&s, l, "f%d", func);
 245                 if (dev_id > 0)
 246                         l = strpcpyf(&s, l, "d%d", dev_id);
 247                 if (l == 0)
 248                         names->pci_path[0] = '\0';
 249         }
 250 out:
 251         udev_device_unref(pci);
 252         return err;
 253 }
 254
 255 static int names_pci(struct udev_device *dev, struct netnames *names) {
 256         struct udev_device *parent;
 257
 258         parent = udev_device_get_parent(dev);
 259         if (!parent)
 260                 return -ENOENT;
 261         /* check if our direct parent is a PCI device with no other bus in-between */
 262         if (streq_ptr("pci", udev_device_get_subsystem(parent))) {
 263                 names->type = NET_PCI;
 264                 names->pcidev = parent;
 265         } else {
 266                 names->pcidev = udev_device_get_parent_with_subsystem_devtype(dev, "pci", NULL);
 267                 if (!names->pcidev)
 268                         return -ENOENT;
 269         }
 270         dev_pci_onboard(dev, names);
 271         dev_pci_slot(dev, names);
 272         return 0;
 273 }
 274
 275 static int names_usb(struct udev_device *dev, struct netnames *names) {
 276         struct udev_device *usbdev;
 277         char name[256];
 278         char *ports;
 279         char *config;
 280         char *interf;
 281         size_t l;
 282         char *s;
 283
 284         usbdev = udev_device_get_parent_with_subsystem_devtype(dev, "usb", "usb_interface");
 285         if (!usbdev)
 286                 return -ENOENT;
 287
 288         /* get USB port number chain, configuration, interface */
 289         strscpy(name, sizeof(name), udev_device_get_sysname(usbdev));
 290         s = strchr(name, '-');
 291         if (!s)
 292                 return -EINVAL;
 293         ports = s+1;
 294
 295         s = strchr(ports, ':');
 296         if (!s)
 297                 return -EINVAL;
 298         s[0] = '\0';
 299         config = s+1;
 300
 301         s = strchr(config, '.');
 302         if (!s)
 303                 return -EINVAL;
 304         s[0] = '\0';
 305         interf = s+1;
 306
 307         /* prefix every port number in the chain with "u"*/
 308         s = ports;
 309         while ((s = strchr(s, '.')))
 310                 s[0] = 'u';
 311         s = names->usb_ports;
 312         l = strpcpyl(&s, sizeof(names->usb_ports), "u", ports, NULL);
 313
 314         /* append USB config number, suppress the common config == 1 */
 315         if (!streq(config, "1"))
 316                 l = strpcpyl(&s, sizeof(names->usb_ports), "c", config, NULL);
 317
 318         /* append USB interface number, suppress the interface == 0 */
 319         if (!streq(interf, "0"))
 320                 l = strpcpyl(&s, sizeof(names->usb_ports), "i", interf, NULL);
 321         if (l == 0)
 322                 return -ENAMETOOLONG;
 323
 324         names->type = NET_USB;
 325         return 0;
 326 }
 327
 328 static int names_bcma(struct udev_device *dev, struct netnames *names) {
 329         struct udev_device *bcmadev;
 330         unsigned int core;
 331
 332         bcmadev = udev_device_get_parent_with_subsystem_devtype(dev, "bcma", NULL);
 333         if (!bcmadev)
 334                 return -ENOENT;
 335
 336         /* bus num:core num */
 337         if (sscanf(udev_device_get_sysname(bcmadev), "bcma%*u:%u", &core) != 1)
 338                 return -EINVAL;
 339         /* suppress the common core == 0 */
 340         if (core > 0)
 341                 snprintf(names->bcma_core, sizeof(names->bcma_core), "b%u", core);
 342
 343         names->type = NET_BCMA;
 344         return 0;
 345 }
 346
 347 static int names_mac(struct udev_device *dev, struct netnames *names) {
 348         const char *s;
 349         unsigned int i;
 350         unsigned int a1, a2, a3, a4, a5, a6;
 351
 352         /* check for NET_ADDR_PERM, skip random MAC addresses */
 353         s = udev_device_get_sysattr_value(dev, "addr_assign_type");
 354         if (!s)
 355                 return EXIT_FAILURE;
 356         i = strtoul(s, NULL, 0);
 357         if (i != 0)
 358                 return 0;
 359
 360         s = udev_device_get_sysattr_value(dev, "address");
 361         if (!s)
 362                 return -ENOENT;
 363         if (sscanf(s, "%x:%x:%x:%x:%x:%x", &a1, &a2, &a3, &a4, &a5, &a6) != 6)
 364                 return -EINVAL;
 365
 366         /* skip empty MAC addresses */
 367         if (a1 + a2 + a3 + a4 + a5 + a6 == 0)
 368                 return -EINVAL;
 369
 370         names->mac[0] = a1;
 371         names->mac[1] = a2;
 372         names->mac[2] = a3;
 373         names->mac[3] = a4;
 374         names->mac[4] = a5;
 375         names->mac[5] = a6;
 376         names->mac_valid = true;
 377         return 0;
 378 }
 379
 380 /* IEEE Organizationally Unique Identifier vendor string */
 381 static int ieee_oui(struct udev_device *dev, struct netnames *names, bool test) {
 382         char str[32];
 383
 384         if (!names->mac_valid)
 385                 return -ENOENT;
 386         /* skip commonly misused 00:00:00 (Xerox) prefix */
 387         if (memcmp(names->mac, "\0\0\0", 3) == 0)
 388                 return -EINVAL;
 389         snprintf(str, sizeof(str), "OUI:%02X%02X%02X%02X%02X%02X",
 390                  names->mac[0], names->mac[1], names->mac[2],
 391                  names->mac[3], names->mac[4], names->mac[5]);
 392         udev_builtin_hwdb_lookup(dev, NULL, str, NULL, test);
 393         return 0;
 394 }
 395
 396 static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool test) {
 397         const char *s;
 398         const char *p;
 399         unsigned int i;
 400         const char *devtype;
 401         const char *prefix = "en";
 402         struct netnames names = {};
 403         int err;
 404
 405         /* handle only ARPHRD_ETHER devices */
 406         s = udev_device_get_sysattr_value(dev, "type");
 407         if (!s)
 408                 return EXIT_FAILURE;
 409         i = strtoul(s, NULL, 0);
 410         if (i != 1)
 411                 return 0;
 412
 413         /* skip stacked devices, like VLANs, ... */
 414         s = udev_device_get_sysattr_value(dev, "ifindex");
 415         if (!s)
 416                 return EXIT_FAILURE;
 417         p = udev_device_get_sysattr_value(dev, "iflink");
 418         if (!p)
 419                 return EXIT_FAILURE;
 420         if (!streq(s, p))
 421                 return 0;
 422
 423         devtype = udev_device_get_devtype(dev);
 424         if (devtype) {
 425                 if (streq("wlan", devtype))
 426                         prefix = "wl";
 427                 else if (streq("wwan", devtype))
 428                         prefix = "ww";
 429         }
 430
 431         err = names_mac(dev, &names);
 432         if (err >= 0 && names.mac_valid) {
 433                 char str[IFNAMSIZ];
 434
 435                 snprintf(str, sizeof(str), "%sx%02x%02x%02x%02x%02x%02x", prefix,
 436                          names.mac[0], names.mac[1], names.mac[2],
 437                          names.mac[3], names.mac[4], names.mac[5]);
 438                 udev_builtin_add_property(dev, test, "ID_NET_NAME_MAC", str);
 439
 440                 ieee_oui(dev, &names, test);
 441         }
 442
 443         /* get PCI based path names, we compose only PCI based paths */
 444         err = names_pci(dev, &names);
 445         if (err < 0)
 446                 goto out;
 447
 448         /* plain PCI device */
 449         if (names.type == NET_PCI) {
 450                 char str[IFNAMSIZ];
 451
 452                 if (names.pci_onboard[0])
 453                         if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard) < (int)sizeof(str))
 454                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_ONBOARD", str);
 455
 456                 if (names.pci_onboard_label)
 457                         if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard_label) < (int)sizeof(str))
 458                                 udev_builtin_add_property(dev, test, "ID_NET_LABEL_ONBOARD", str);
 459
 460                 if (names.pci_path[0])
 461                         if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_path) < (int)sizeof(str))
 462                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
 463
 464                 if (names.pci_slot[0])
 465                         if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_slot) < (int)sizeof(str))
 466                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
 467                 goto out;
 468         }
 469
 470         /* USB device */
 471         err = names_usb(dev, &names);
 472         if (err >= 0 && names.type == NET_USB) {
 473                 char str[IFNAMSIZ];
 474
 475                 if (names.pci_path[0])
 476                         if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.usb_ports) < (int)sizeof(str))
 477                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
 478
 479                 if (names.pci_slot[0])
 480                         if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.usb_ports) < (int)sizeof(str))
 481                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
 482                 goto out;
 483         }
 484
 485         /* Broadcom bus */
 486         err = names_bcma(dev, &names);
 487         if (err >= 0 && names.type == NET_BCMA) {
 488                 char str[IFNAMSIZ];
 489
 490                 if (names.pci_path[0])
 491                         if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.bcma_core) < (int)sizeof(str))
 492                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
 493
 494                 if (names.pci_slot[0])
 495                         if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.bcma_core) < (int)sizeof(str))
 496                                 udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
 497                 goto out;
 498         }
 499
 500 out:
 501         return EXIT_SUCCESS;
 502 }
 503
 504 const struct udev_builtin udev_builtin_net_id = {
 505         .name = "net_id",
 506         .cmd = builtin_net_id,
 507         .help = "network device properties",
 508 };