systemd/src/udev/udev-builtin-net_id.c

/***
  This file is part of systemd.

  Copyright 2012 Kay Sievers <kay@vrfy.org>

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

/*
 * prefixes:
 *   en -- ethernet
 *   wl -- wlan
 *   ww -- wwan
 *
 * types:
 *   o<index>                 -- on-board device index
 *   s<slot>f<function>       -- hotplug slot number
 *   x<MAC>                   -- MAC address
 *   p<bus>s<slot>f<function> -- PCI/physical location
 *
 * example:
 *   ID_NET_NAME_ONBOARD=eno1
 *   ID_NET_NAME_SLOT=ens1f0
 *   ID_NET_NAME_MAC=enxf0def180d479
 *   ID_NET_NAME_PATH=enp19s0f0
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>

#include "udev.h"

/* retrieve on-board index number and label from firmware */
static int dev_pci_onboard(struct udev_device *dev, const char *prefix, bool test) {
        const char *index;
        int idx;
        const char *label;
        char s[16];
        int err;

        /* ACPI _DSM  -- device specific method for naming a PCI or PCI Express device */
        index = udev_device_get_sysattr_value(dev, "acpi_index");
        /* SMBIOS type 41 -- Onboard Devices Extended Information */
        if (!index)
                index = udev_device_get_sysattr_value(dev, "index");
        if (!index)
                return -ENOENT;
        idx = strtoul(index, NULL, 0);
        if (idx <= 0)
                return -EINVAL;
        snprintf(s, sizeof(s), "%so%d", prefix, idx);
        err = udev_builtin_add_property(dev, test, "ID_NET_NAME_ONBOARD", s);
        if (err < 0)
                return err;

        label = udev_device_get_sysattr_value(dev, "label");
        if (label) {
                err = udev_builtin_add_property(dev, test, "ID_NET_LABEL_ONBOARD", label);
                if (err < 0)
                        return err;
        }
        return 0;
}

static int dev_pci_slot(struct udev_device *dev, const char *prefix, bool test) {
        struct udev *udev = udev_device_get_udev(dev);
        unsigned int bus;
        unsigned int slot;
        unsigned int func;
        struct udev_device *pci = NULL;
        char slots[256];
        DIR *dir;
        struct dirent *dent;
        char str[256];
        int hotplug_slot = 0;
        int err = 0;

        /* compose a name based on the raw kernel's PCI bus, slot numbers */
        if (sscanf(udev_device_get_sysname(dev), "0000:%x:%x.%d", &bus, &slot, &func) != 3)
                return -ENOENT;
        snprintf(str, sizeof(str), "%sp%ds%df%d", prefix, bus, slot, func);
        err = udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
        if (err < 0)
                return err;

        /* ACPI _SUN  -- slot user number */
        pci = udev_device_new_from_subsystem_sysname(udev, "subsystem", "pci");
        if (!pci) {
                err = -ENOENT;
                goto out;
        }
        snprintf(slots, sizeof(slots), "%s/slots", udev_device_get_syspath(pci));
        dir = opendir(slots);
        if (!dir) {
                err = -errno;
                goto out;
        }

        for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
                int i;
                char *rest;
                char *address;

                if (dent->d_name[0] == '.')
                        continue;
                i = strtol(dent->d_name, &rest, 10);
                if (rest[0] != '\0')
                        continue;
                if (i < 1)
                        continue;
                snprintf(str, sizeof(str), "%s/%s/address", slots, dent->d_name);
                if (read_one_line_file(str, &address) >= 0) {
                        /* match slot address with device by stripping the function */
                        if (strncmp(address, udev_device_get_sysname(dev), strlen(address)) == 0)
                                hotplug_slot = i;
                        free(address);
                }

                if (hotplug_slot > 0)
                        break;
        }
        closedir(dir);

        if (hotplug_slot > 0) {
                snprintf(str, sizeof(str), "%ss%df%d", prefix, hotplug_slot, func);
                err = udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
        }
out:
        udev_device_unref(pci);
        return err;
}

static int dev_pci(struct udev_device *dev, const char *prefix, bool test) {
        struct udev_device *d;

        /* skip other buses than direct PCI parents */
        d = udev_device_get_parent(dev);
        if (!d || !streq("pci", udev_device_get_subsystem(d)))
                return -ENOENT;

        dev_pci_onboard(d, prefix, test);
        dev_pci_slot(d, prefix, test);
        return 0;
}

static int dev_mac(struct udev_device *dev, const char *prefix, bool test) {
        const char *s;
        unsigned int i;
        unsigned int a1, a2, a3, a4, a5, a6;
        char str[16];

        /* check for NET_ADDR_PERM, skip random MAC addresses */
        s = udev_device_get_sysattr_value(dev, "addr_assign_type");
        if (!s)
                return EXIT_FAILURE;
        i = strtoul(s, NULL, 0);
        if (i != 0)
                return 0;

        s = udev_device_get_sysattr_value(dev, "address");
        if (!s)
                return -ENOENT;
        if (sscanf(s, "%x:%x:%x:%x:%x:%x", &a1, &a2, &a3, &a4, &a5, &a6) != 6)
                return -EINVAL;

        /* skip empty MAC addresses */
        if (a1 + a2 + a3 + a4 + a5 + a6 == 0)
                return -EINVAL;

        /* add IEEE Organizationally Unique Identifier */
        snprintf(str, sizeof(str), "OUI:%X%X%X", a1, a2, a3);
        udev_builtin_hwdb_lookup(dev, str, test);

        snprintf(str, sizeof(str), "%sx%x%x%x%x%x%x", prefix, a1, a2, a3, a4, a5, a6);
        return udev_builtin_add_property(dev, test, "ID_NET_NAME_MAC", str);
}

static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool test) {
        const char *s;
        unsigned int i;
        const char *devtype;
        const char *prefix = "en";

        /* handle only ARPHRD_ETHER devices */
        s = udev_device_get_sysattr_value(dev, "type");
        if (!s)
                return EXIT_FAILURE;
        i = strtoul(s, NULL, 0);
        if (i != 1)
                return 0;

        devtype = udev_device_get_devtype(dev);
        if (devtype) {
                if (streq("wlan", devtype))
                        prefix = "wl";
                else if (streq("wwan", devtype))
                        prefix = "ww";
        }

        dev_pci(dev, prefix, test);
        dev_mac(dev, prefix, test);
        return EXIT_SUCCESS;
}

const struct udev_builtin udev_builtin_net_id = {
        .name = "net_id",
        .cmd = builtin_net_id,
        .help = "network device properties",
};