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Systemd/src/udev/udev-builtin-net_id.c
Jason S. McMullan 0454229c10 udev/net_id: Only read the first 64 bytes of PCI config space 
The original code used fread(), which on some libc implementions
(ie glibc 2.17) would pre-read a full 4K (PAGE_SIZE) of the
PCI config space, when only 64 bytes were requested.

I have recently come across PCIe hardware which responds with
Completion Timeouts when accesses above 256 bytes are attempted.

This can cause server systems with GHES/AEPI support to cause
and immediate kernel panic due to the failed PCI transaction.

This change replaces the buffered fread() with an explict
unbuffered read() of 64 bytes, which corrects this issue by
only reading the guaranteed first 64 bytes of PCIe config space.
2015-05-22 20:50:01 +02:00

585 lines
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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;
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;
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;
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;
/* 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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