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systemd/src/udev/udev-builtin-net_id.c
Tom Gundersen 3b64e4d4f4 udev: add some asserts 
Mostly for documentation purposes.
2015-06-02 18:12:47 +02:00

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/***
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/>.
***/
/*
* Predictable network interface device names based on:
* - firmware/bios-provided index numbers for on-board devices
* - firmware-provided pci-express hotplug slot index number
* - physical/geographical location of the hardware
* - the interface's MAC address
*
* http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames
*
* Two character prefixes based on the type of interface:
* en -- ethernet
* sl -- serial line IP (slip)
* wl -- wlan
* ww -- wwan
*
* Type of names:
* b<number> -- BCMA bus core number
* ccw<name> -- CCW bus group name
* o<index>[d<dev_port>] -- on-board device index number
* s<slot>[f<function>][d<dev_port>] -- hotplug slot index number
* x<MAC> -- MAC address
* [P<domain>]p<bus>s<slot>[f<function>][d<dev_port>]
* -- PCI geographical location
* [P<domain>]p<bus>s<slot>[f<function>][u<port>][..][c<config>][i<interface>]
* -- USB port number chain
*
* All multi-function PCI devices will carry the [f<function>] number in the
* device name, including the function 0 device.
*
* When using PCI geography, The PCI domain is only prepended when it is not 0.
*
* For USB devices the full chain of port numbers of hubs is composed. If the
* name gets longer than the maximum number of 15 characters, the name is not
* exported.
* The usual USB configuration == 1 and interface == 0 values are suppressed.
*
* PCI ethernet card with firmware index "1":
* ID_NET_NAME_ONBOARD=eno1
* ID_NET_NAME_ONBOARD_LABEL=Ethernet Port 1
*
* PCI ethernet card in hotplug slot with firmware index number:
* /sys/devices/pci0000:00/0000:00:1c.3/0000:05:00.0/net/ens1
* ID_NET_NAME_MAC=enx000000000466
* ID_NET_NAME_PATH=enp5s0
* ID_NET_NAME_SLOT=ens1
*
* PCI ethernet multi-function card with 2 ports:
* /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.0/net/enp2s0f0
* ID_NET_NAME_MAC=enx78e7d1ea46da
* ID_NET_NAME_PATH=enp2s0f0
* /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.1/net/enp2s0f1
* ID_NET_NAME_MAC=enx78e7d1ea46dc
* ID_NET_NAME_PATH=enp2s0f1
*
* PCI wlan card:
* /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlp3s0
* ID_NET_NAME_MAC=wlx0024d7e31130
* ID_NET_NAME_PATH=wlp3s0
*
* USB built-in 3G modem:
* /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.6/net/wwp0s29u1u4i6
* ID_NET_NAME_MAC=wwx028037ec0200
* ID_NET_NAME_PATH=wwp0s29u1u4i6
*
* USB Android phone:
* /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/net/enp0s29u1u2
* ID_NET_NAME_MAC=enxd626b3450fb5
* ID_NET_NAME_PATH=enp0s29u1u2
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <linux/pci_regs.h>
#include "udev.h"
#include "fileio.h"
enum netname_type{
NET_UNDEF,
NET_PCI,
NET_USB,
NET_BCMA,
NET_VIRTIO,
NET_CCWGROUP,
};
struct netnames {
enum netname_type type;
uint8_t mac[6];
bool mac_valid;
struct udev_device *pcidev;
char pci_slot[IFNAMSIZ];
char pci_path[IFNAMSIZ];
char pci_onboard[IFNAMSIZ];
const char *pci_onboard_label;
char usb_ports[IFNAMSIZ];
char bcma_core[IFNAMSIZ];
char ccw_group[IFNAMSIZ];
};
/* retrieve on-board index number and label from firmware */
static int dev_pci_onboard(struct udev_device *dev, struct netnames *names) {
unsigned dev_port = 0;
size_t l;
char *s;
const char *attr;
int idx;
/* ACPI _DSM -- device specific method for naming a PCI or PCI Express device */
attr = udev_device_get_sysattr_value(names->pcidev, "acpi_index");
/* SMBIOS type 41 -- Onboard Devices Extended Information */
if (!attr)
attr = udev_device_get_sysattr_value(names->pcidev, "index");
if (!attr)
return -ENOENT;
idx = strtoul(attr, NULL, 0);
if (idx <= 0)
return -EINVAL;
/* kernel provided port index for multiple ports on a single PCI function */
attr = udev_device_get_sysattr_value(dev, "dev_port");
if (attr)
dev_port = strtol(attr, NULL, 10);
s = names->pci_onboard;
l = sizeof(names->pci_onboard);
l = strpcpyf(&s, l, "o%d", idx);
if (dev_port > 0)
l = strpcpyf(&s, l, "d%d", dev_port);
if (l == 0)
names->pci_onboard[0] = '\0';
names->pci_onboard_label = udev_device_get_sysattr_value(names->pcidev, "label");
return 0;
}
/* read the 256 bytes PCI configuration space to check the multi-function bit */
static bool is_pci_multifunction(struct udev_device *dev) {
_cleanup_close_ int fd = -1;
const char *filename;
uint8_t config[64];
filename = strjoina(udev_device_get_syspath(dev), "/config");
fd = open(filename, O_RDONLY | O_CLOEXEC);
if (fd < 0)
return false;
if (read(fd, &config, sizeof(config)) != sizeof(config))
return false;
/* bit 0-6 header type, bit 7 multi/single function device */
if ((config[PCI_HEADER_TYPE] & 0x80) != 0)
return true;
return false;
}
static int dev_pci_slot(struct udev_device *dev, struct netnames *names) {
struct udev *udev = udev_device_get_udev(names->pcidev);
unsigned domain, bus, slot, func, dev_port = 0;
size_t l;
char *s;
const char *attr;
struct udev_device *pci = NULL;
char slots[256], str[256];
_cleanup_closedir_ DIR *dir = NULL;
struct dirent *dent;
int hotplug_slot = 0, err = 0;
if (sscanf(udev_device_get_sysname(names->pcidev), "%x:%x:%x.%u", &domain, &bus, &slot, &func) != 4)
return -ENOENT;
/* kernel provided port index for multiple ports on a single PCI function */
attr = udev_device_get_sysattr_value(dev, "dev_port");
if (attr)
dev_port = strtol(attr, NULL, 10);
/* compose a name based on the raw kernel's PCI bus, slot numbers */
s = names->pci_path;
l = sizeof(names->pci_path);
if (domain > 0)
l = strpcpyf(&s, l, "P%u", domain);
l = strpcpyf(&s, l, "p%us%u", bus, slot);
if (func > 0 || is_pci_multifunction(names->pcidev))
l = strpcpyf(&s, l, "f%u", func);
if (dev_port > 0)
l = strpcpyf(&s, l, "d%u", dev_port);
if (l == 0)
names->pci_path[0] = '\0';
/* 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 (strneq(address, udev_device_get_sysname(names->pcidev), strlen(address)))
hotplug_slot = i;
free(address);
}
if (hotplug_slot > 0)
break;
}
if (hotplug_slot > 0) {
s = names->pci_slot;
l = sizeof(names->pci_slot);
if (domain > 0)
l = strpcpyf(&s, l, "P%d", domain);
l = strpcpyf(&s, l, "s%d", hotplug_slot);
if (func > 0 || is_pci_multifunction(names->pcidev))
l = strpcpyf(&s, l, "f%d", func);
if (dev_port > 0)
l = strpcpyf(&s, l, "d%d", dev_port);
if (l == 0)
names->pci_slot[0] = '\0';
}
out:
udev_device_unref(pci);
return err;
}
static int names_pci(struct udev_device *dev, struct netnames *names) {
struct udev_device *parent;
assert(dev);
assert(names);
parent = udev_device_get_parent(dev);
if (!parent)
return -ENOENT;
/* check if our direct parent is a PCI device with no other bus in-between */
if (streq_ptr("pci", udev_device_get_subsystem(parent))) {
names->type = NET_PCI;
names->pcidev = parent;
} else {
names->pcidev = udev_device_get_parent_with_subsystem_devtype(dev, "pci", NULL);
if (!names->pcidev)
return -ENOENT;
}
dev_pci_onboard(dev, names);
dev_pci_slot(dev, names);
return 0;
}
static int names_usb(struct udev_device *dev, struct netnames *names) {
struct udev_device *usbdev;
char name[256];
char *ports;
char *config;
char *interf;
size_t l;
char *s;
assert(dev);
assert(names);
usbdev = udev_device_get_parent_with_subsystem_devtype(dev, "usb", "usb_interface");
if (!usbdev)
return -ENOENT;
/* get USB port number chain, configuration, interface */
strscpy(name, sizeof(name), udev_device_get_sysname(usbdev));
s = strchr(name, '-');
if (!s)
return -EINVAL;
ports = s+1;
s = strchr(ports, ':');
if (!s)
return -EINVAL;
s[0] = '\0';
config = s+1;
s = strchr(config, '.');
if (!s)
return -EINVAL;
s[0] = '\0';
interf = s+1;
/* prefix every port number in the chain with "u" */
s = ports;
while ((s = strchr(s, '.')))
s[0] = 'u';
s = names->usb_ports;
l = strpcpyl(&s, sizeof(names->usb_ports), "u", ports, NULL);
/* append USB config number, suppress the common config == 1 */
if (!streq(config, "1"))
l = strpcpyl(&s, sizeof(names->usb_ports), "c", config, NULL);
/* append USB interface number, suppress the interface == 0 */
if (!streq(interf, "0"))
l = strpcpyl(&s, sizeof(names->usb_ports), "i", interf, NULL);
if (l == 0)
return -ENAMETOOLONG;
names->type = NET_USB;
return 0;
}
static int names_bcma(struct udev_device *dev, struct netnames *names) {
struct udev_device *bcmadev;
unsigned int core;
assert(dev);
assert(names);
bcmadev = udev_device_get_parent_with_subsystem_devtype(dev, "bcma", NULL);
if (!bcmadev)
return -ENOENT;
/* bus num:core num */
if (sscanf(udev_device_get_sysname(bcmadev), "bcma%*u:%u", &core) != 1)
return -EINVAL;
/* suppress the common core == 0 */
if (core > 0)
snprintf(names->bcma_core, sizeof(names->bcma_core), "b%u", core);
names->type = NET_BCMA;
return 0;
}
static int names_ccw(struct udev_device *dev, struct netnames *names) {
struct udev_device *cdev;
const char *bus_id;
size_t bus_id_len;
int rc;
assert(dev);
assert(names);
/* Retrieve the associated CCW device */
cdev = udev_device_get_parent(dev);
if (!cdev)
return -ENOENT;
/* Network devices are always grouped CCW devices */
if (!streq_ptr("ccwgroup", udev_device_get_subsystem(cdev)))
return -ENOENT;
/* Retrieve bus-ID of the grouped CCW device. The bus-ID uniquely
* identifies the network device on the Linux on System z channel
* subsystem. Note that the bus-ID contains lowercase characters.
*/
bus_id = udev_device_get_sysname(cdev);
if (!bus_id)
return -ENOENT;
/* Check the length of the bus-ID. Rely on that the kernel provides
* a correct bus-ID; alternatively, improve this check and parse and
* verify each bus-ID part...
*/
bus_id_len = strlen(bus_id);
if (!bus_id_len || bus_id_len < 8 || bus_id_len > 9)
return -EINVAL;
/* Store the CCW bus-ID for use as network device name */
rc = snprintf(names->ccw_group, sizeof(names->ccw_group), "ccw%s", bus_id);
if (rc >= 0 && rc < (int)sizeof(names->ccw_group))
names->type = NET_CCWGROUP;
return 0;
}
static int names_mac(struct udev_device *dev, struct netnames *names) {
const char *s;
unsigned int i;
unsigned int a1, a2, a3, a4, a5, a6;
/* 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;
names->mac[0] = a1;
names->mac[1] = a2;
names->mac[2] = a3;
names->mac[3] = a4;
names->mac[4] = a5;
names->mac[5] = a6;
names->mac_valid = true;
return 0;
}
/* IEEE Organizationally Unique Identifier vendor string */
static int ieee_oui(struct udev_device *dev, struct netnames *names, bool test) {
char str[32];
if (!names->mac_valid)
return -ENOENT;
/* skip commonly misused 00:00:00 (Xerox) prefix */
if (memcmp(names->mac, "\0\0\0", 3) == 0)
return -EINVAL;
snprintf(str, sizeof(str), "OUI:%02X%02X%02X%02X%02X%02X",
names->mac[0], names->mac[1], names->mac[2],
names->mac[3], names->mac[4], names->mac[5]);
udev_builtin_hwdb_lookup(dev, NULL, str, NULL, test);
return 0;
}
static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool test) {
const char *s;
const char *p;
unsigned int i;
const char *devtype;
const char *prefix = "en";
struct netnames names = {};
int err;
/* handle only ARPHRD_ETHER and ARPHRD_SLIP devices */
s = udev_device_get_sysattr_value(dev, "type");
if (!s)
return EXIT_FAILURE;
i = strtoul(s, NULL, 0);
switch (i) {
case ARPHRD_ETHER:
prefix = "en";
break;
case ARPHRD_SLIP:
prefix = "sl";
break;
default:
return 0;
}
/* skip stacked devices, like VLANs, ... */
s = udev_device_get_sysattr_value(dev, "ifindex");
if (!s)
return EXIT_FAILURE;
p = udev_device_get_sysattr_value(dev, "iflink");
if (!p)
return EXIT_FAILURE;
if (!streq(s, p))
return 0;
devtype = udev_device_get_devtype(dev);
if (devtype) {
if (streq("wlan", devtype))
prefix = "wl";
else if (streq("wwan", devtype))
prefix = "ww";
}
err = names_mac(dev, &names);
if (err >= 0 && names.mac_valid) {
char str[IFNAMSIZ];
snprintf(str, sizeof(str), "%sx%02x%02x%02x%02x%02x%02x", prefix,
names.mac[0], names.mac[1], names.mac[2],
names.mac[3], names.mac[4], names.mac[5]);
udev_builtin_add_property(dev, test, "ID_NET_NAME_MAC", str);
ieee_oui(dev, &names, test);
}
/* get path names for Linux on System z network devices */
err = names_ccw(dev, &names);
if (err >= 0 && names.type == NET_CCWGROUP) {
char str[IFNAMSIZ];
if (snprintf(str, sizeof(str), "%s%s", prefix, names.ccw_group) < (int)sizeof(str))
udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
goto out;
}
/* get PCI based path names, we compose only PCI based paths */
err = names_pci(dev, &names);
if (err < 0)
goto out;
/* plain PCI device */
if (names.type == NET_PCI) {
char str[IFNAMSIZ];
if (names.pci_onboard[0])
if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard) < (int)sizeof(str))
udev_builtin_add_property(dev, test, "ID_NET_NAME_ONBOARD", str);
if (names.pci_onboard_label)
if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_onboard_label) < (int)sizeof(str))
udev_builtin_add_property(dev, test, "ID_NET_LABEL_ONBOARD", str);
if (names.pci_path[0])
if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_path) < (int)sizeof(str))
udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
if (names.pci_slot[0])
if (snprintf(str, sizeof(str), "%s%s", prefix, names.pci_slot) < (int)sizeof(str))
udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
goto out;
}
/* USB device */
err = names_usb(dev, &names);
if (err >= 0 && names.type == NET_USB) {
char str[IFNAMSIZ];
if (names.pci_path[0])
if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.usb_ports) < (int)sizeof(str))
udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
if (names.pci_slot[0])
if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.usb_ports) < (int)sizeof(str))
udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
goto out;
}
/* Broadcom bus */
err = names_bcma(dev, &names);
if (err >= 0 && names.type == NET_BCMA) {
char str[IFNAMSIZ];
if (names.pci_path[0])
if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_path, names.bcma_core) < (int)sizeof(str))
udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
if (names.pci_slot[0])
if (snprintf(str, sizeof(str), "%s%s%s", prefix, names.pci_slot, names.bcma_core) < (int)sizeof(str))
udev_builtin_add_property(dev, test, "ID_NET_NAME_SLOT", str);
goto out;
}
out:
return EXIT_SUCCESS;
}
const struct udev_builtin udev_builtin_net_id = {
.name = "net_id",
.cmd = builtin_net_id,
.help = "Network device properties",
};
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