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From 08f8572347ca597147ab761d425e4480885e1995 Mon Sep 17 00:00:00 2001
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From: Hendrik Brueckner <brueckner@redhat.com>
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Date: Thu, 9 Jan 2014 11:28:12 +0100
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Subject: [PATCH] udev/net_id: Introduce predictable network names for Linux on
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 System z
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Use the bus-ID to create predicatable devices names for network interfaces
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on Linux on System z instances.  The bus-ID identifies a device in the s390
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channel subsystem.
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Network interfaces of device type Ethernet are named as:
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    enccw0.0.1234    (13 characters)
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up to
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    enccwff.7.ffff   (14 characters)
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CTC network devices of device type SLIP, use a different prefix as follows:
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    slccw0.0.1234    (13 characters)
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See also Red Hat Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=870859
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[tomegun: typical problem of netdevs switching names between reboots.]
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Conflicts:
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	src/udev/udev-builtin-net_id.c
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---
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 src/udev/udev-builtin-net_id.c | 64 ++++++++++++++++++++++++++++++++++++++++--
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 1 file changed, 62 insertions(+), 2 deletions(-)
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diff --git a/src/udev/udev-builtin-net_id.c b/src/udev/udev-builtin-net_id.c
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index 9ae8f08..d9de46d 100644
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--- a/src/udev/udev-builtin-net_id.c
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+++ b/src/udev/udev-builtin-net_id.c
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@@ -28,6 +28,7 @@
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  *
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  * Two character prefixes based on the type of interface:
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  *   en -- ethernet
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+ *   sl -- serial line IP (slip)
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  *   wl -- wlan
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  *   ww -- wwan
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  *
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@@ -101,6 +102,7 @@ enum netname_type{
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         NET_PCI,
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         NET_USB,
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         NET_BCMA,
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+        NET_CCWGROUP,
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 };
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 struct netnames {
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@@ -118,6 +120,8 @@ struct netnames {
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         char usb_ports[IFNAMSIZ];
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         char bcma_core[IFNAMSIZ];
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+
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+        char ccw_core[IFNAMSIZ];
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 };
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 /* retrieve on-board index number and label from firmware */
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@@ -351,6 +355,44 @@ static int names_bcma(struct udev_device *dev, struct netnames *names) {
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         return 0;
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 }
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+static int names_ccw(struct  udev_device *dev, struct netnames *names) {
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+        struct udev_device *cdev;
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+        const char *bus_id;
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+        size_t bus_id_len;
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+        int rc;
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+
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+        /* Retrieve the associated CCW device */
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+        cdev = udev_device_get_parent(dev);
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+        if (!cdev)
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+                return -ENOENT;
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+
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+        /* Network devices are always grouped CCW devices */
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+        if (!streq_ptr("ccwgroup", udev_device_get_subsystem(cdev)))
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+                return -ENOENT;
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+
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+        /* Retrieve bus-ID of the grouped CCW device.  The bus-ID uniquely
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+         * identifies the network device on the Linux on System z channel
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+         * subsystem.  Note that the bus-ID contains lowercase characters.
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+         */
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+        bus_id = udev_device_get_sysname(cdev);
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+        if (!bus_id)
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+                return -ENOENT;
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+
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+        /* Check the length of the bus-ID.  Rely on that the kernel provides
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+         * a correct bus-ID; alternatively, improve this check and parse and
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+         * verify each bus-ID part...
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+         */
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+        bus_id_len = strlen(bus_id);
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+        if (!bus_id_len || bus_id_len < 8 || bus_id_len > 9)
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+                return -EINVAL;
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+
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+        /* Store the CCW bus-ID for use as network device name */
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+        rc = snprintf(names->ccw_core, sizeof(names->ccw_core), "ccw%s", bus_id);
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+        if (rc >= 0 && rc < (int)sizeof(names->ccw_core))
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+                names->type = NET_CCWGROUP;
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+        return 0;
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+}
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+
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 static int names_mac(struct udev_device *dev, struct netnames *names) {
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         const char *s;
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         unsigned int i;
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@@ -409,13 +451,21 @@ static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool
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         struct netnames names = {};
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         int err;
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-        /* handle only ARPHRD_ETHER devices */
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+        /* handle only ARPHRD_ETHER and ARPHRD_SLIP devices */
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         s = udev_device_get_sysattr_value(dev, "type");
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         if (!s)
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                 return EXIT_FAILURE;
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         i = strtoul(s, NULL, 0);
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-        if (i != 1)
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+        switch (i) {
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+        case 1: /* ARPHRD_ETHER */
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+                prefix = "en";
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+                break;
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+        case 256: /* ARPHRD_SLIP */
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+                prefix = "sl";
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+                break;
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+        default:
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                 return 0;
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+        }
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         /* skip stacked devices, like VLANs, ... */
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         s = udev_device_get_sysattr_value(dev, "ifindex");
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@@ -447,6 +497,16 @@ static int builtin_net_id(struct udev_device *dev, int argc, char *argv[], bool
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                 ieee_oui(dev, &names, test);
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         }
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+        /* get path names for Linux on System z network devices */
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+        err = names_ccw(dev, &names);
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+        if (err >= 0 && names.type == NET_CCWGROUP) {
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+                char str[IFNAMSIZ];
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+
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+                if (snprintf(str, sizeof(str), "%s%s", prefix, names.ccw_core) < (int)sizeof(str))
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+                        udev_builtin_add_property(dev, test, "ID_NET_NAME_PATH", str);
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+                goto out;
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+        }
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+
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         /* get PCI based path names, we compose only PCI based paths */
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         err = names_pci(dev, &names);
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         if (err < 0)