udev-builtin-net_id: align VF representor names with VF names

Certain cards support to set their eswitch to switchdev mode. In this
mode for each created VF there is also created so called VF representor.
This representor is helper network interface used for configuration of
mentioned eswitch and belongs to an appropriate PF.

VF representors are identified by the specific value of phys_port_name
attribute and the value has format "pfMvfN" where M is PF function
number and N is VF number inside this PF.

As the VF representor interfaces belong to PF PCI device the naming
scheme used for them is the same like for other PCI devices. In this
case name of PF interface is used and phys_port_name suffix is appended.

E.g.
 PF=enp65s0f0np0 # phys_port_name for PF interface is 'p0'
 VF=enp65s0f0np0v0 # v0 is appended for VF0 in case of NAMING_SR_IOV_V
REP=enp65s0f0np0pf0vf0 # phys_port_name for VF0 representor is 'pf0vf0'

First as the phys_port_name for representors is long (6+ chars) then the
generated name does not fit into IFNAMSIZ so this name is used only as
alternate interface name and for the primary one is used generic one
like eth<N>. Second 'f0' and 'pf0' in REP name is redundant.

This patch fixes this issue by introducing another naming scheme for VF
representors and appending 'rN' suffix to PF interface name for them.
N is VF number so the name used for representor interface is similar to
VF interface and differs only by the suffix.

For the example above we get:
 PF=enp65s0f0np0
 VF=enp65s0f0np0v0
REP=enp65s0f0np0r0

This eases for userspace to determine which representor interface
represents particular VF.

Signed-off-by: Ivan Vecera <ivecera@redhat.com>

man/systemd.net-naming-scheme.xml

@@ -159,6 +159,7 @@
           <term><varname>ID_NET_NAME_SLOT=<replaceable>prefix</replaceable>[<constant>P</constant><replaceable>domain</replaceable>]<constant>s</constant><replaceable>slot</replaceable>[<constant>f</constant><replaceable>function</replaceable>][<constant>n</constant><replaceable>port_name</replaceable>|<constant>d</constant><replaceable>dev_port</replaceable>]<constant>b</constant><replaceable>number</replaceable></varname></term>
           <term><varname>ID_NET_NAME_SLOT=<replaceable>prefix</replaceable>[<constant>P</constant><replaceable>domain</replaceable>]<constant>s</constant><replaceable>slot</replaceable>[<constant>f</constant><replaceable>function</replaceable>][<constant>n</constant><replaceable>port_name</replaceable>|<constant>d</constant><replaceable>dev_port</replaceable>]<constant>u</constant><replaceable>port</replaceable>…[<constant>c</constant><replaceable>config</replaceable>][<constant>i</constant><replaceable>interface</replaceable>]</varname></term>
           <term><varname>ID_NET_NAME_SLOT=<replaceable>prefix</replaceable>[<constant>P</constant><replaceable>domain</replaceable>]<constant>s</constant><replaceable>slot</replaceable>[<constant>f</constant><replaceable>function</replaceable>][<constant>n</constant><replaceable>port_name</replaceable>|<constant>d</constant><replaceable>dev_port</replaceable>]<constant>v</constant><replaceable>slot</replaceable></varname></term>
+          <term><varname>ID_NET_NAME_SLOT=<replaceable>prefix</replaceable>[<constant>P</constant><replaceable>domain</replaceable>]<constant>s</constant><replaceable>slot</replaceable>[<constant>f</constant><replaceable>function</replaceable>][<constant>n</constant><replaceable>port_name</replaceable>|<constant>d</constant><replaceable>dev_port</replaceable>]<constant>r</constant><replaceable>slot</replaceable></varname></term>
 
           <listitem><para>This property describes the slot position. Different schemes are used depending on
           the bus type, as described in the table below. In case of USB, BCMA, and SR-VIO devices, the full
@@ -206,6 +207,11 @@
                   <entry>… <constant>v</constant><replaceable>slot</replaceable></entry>
                   <entry>SR-VIO slot number</entry>
                 </row>
+
+                <row>
+                  <entry>… <constant>r</constant><replaceable>slot</replaceable></entry>
+                  <entry>SR-IOV slot number</entry>
+                </row>
               </tbody>
             </tgroup>
           </table>
@@ -226,6 +232,11 @@
           <constant>v</constant> and the virtual device number, with any leading zeros removed. The bus
           number is ignored.</para>
 
+          <para>SR-IOV virtual device representors are named based on the name of the physical device
+          interface, with a suffix of <constant>r</constant> and the number of the virtual device that
+          is linked to the particular representor, with any leading zeros removed. The physical port
+          name and the bus number are ignored.</para>
+
           <para>In some configurations a parent PCI bridge of a given network controller may be associated
           with a slot. In such case we don't generate this device property to avoid possible naming conflicts.</para>
           </listitem>
@@ -457,6 +468,17 @@
           </listitem>
         </varlistentry>
 
+        <varlistentry>
+          <term><constant>v254</constant></term>
+
+          <listitem><para>Naming was changed for SR-IOV virtual device representors.</para>
+
+          <para>The <literal>r<replaceable>slot</replaceable></literal> suffix was added to differentiate SR-IOV
+          virtual device representors attached to a single physical device interface.
+          </para>
+          </listitem>
+        </varlistentry>
+
       </variablelist>
 
     <para>Note that <constant>latest</constant> may be used to denote the latest scheme known (to this

src/shared/netif-naming-scheme.h

@@ -39,6 +39,7 @@ typedef enum NamingSchemeFlags {
         NAMING_BRIDGE_MULTIFUNCTION_SLOT = 1 << 14, /* Use PCI hotplug slot information associated with bridge, but only if PCI device is multifunction */
         NAMING_DEVICETREE_ALIASES        = 1 << 15, /* Generate names from devicetree aliases */
         NAMING_USB_HOST                  = 1 << 16, /* Generate names for usb host */
+        NAMING_SR_IOV_R                  = 1 << 17, /* Use "r" suffix for SR-IOV VF representors */
 
         /* And now the masks that combine the features above */
         NAMING_V238 = 0,
@@ -53,6 +54,7 @@ typedef enum NamingSchemeFlags {
         NAMING_V251 = NAMING_V250 | NAMING_BRIDGE_MULTIFUNCTION_SLOT,
         NAMING_V252 = NAMING_V251 | NAMING_DEVICETREE_ALIASES,
         NAMING_V253 = NAMING_V252 | NAMING_USB_HOST,
+        NAMING_V254 = NAMING_V253 | NAMING_SR_IOV_R,
 
         EXTRA_NET_NAMING_SCHEMES
 

src/udev/udev-builtin-net_id.c

@@ -80,6 +80,7 @@ typedef struct LinkInfo {
         int ifindex;
         int iflink;
         int iftype;
+        int vf_representor_id;
         const char *devtype;
         const char *phys_port_name;
         struct hw_addr_data hw_addr;
@@ -208,7 +209,10 @@ static int dev_pci_onboard(sd_device *dev, const LinkInfo *info, NetNames *names
         s = names->pci_onboard;
         l = sizeof(names->pci_onboard);
         l = strpcpyf(&s, l, "o%lu", idx);
-        if (!isempty(info->phys_port_name))
+        if (naming_scheme_has(NAMING_SR_IOV_R) && info->vf_representor_id >= 0)
+                /* For VF representor append 'r<VF_NUM>' and not phys_port_name */
+                l = strpcpyf(&s, l, "r%d", info->vf_representor_id);
+        else if (!isempty(info->phys_port_name))
                 /* kernel provided front panel port name for multiple port PCI device */
                 l = strpcpyf(&s, l, "n%s", info->phys_port_name);
         else if (dev_port > 0)
@@ -391,7 +395,10 @@ static int dev_pci_slot(sd_device *dev, const LinkInfo *info, NetNames *names) {
         l = strpcpyf(&s, l, "p%us%u", bus, slot);
         if (func > 0 || is_pci_multifunction(names->pcidev) > 0)
                 l = strpcpyf(&s, l, "f%u", func);
-        if (!isempty(info->phys_port_name))
+        if (naming_scheme_has(NAMING_SR_IOV_R) && info->vf_representor_id >= 0)
+                /* For VF representor append 'r<VF_NUM>' and not phys_port_name */
+                l = strpcpyf(&s, l, "r%d", info->vf_representor_id);
+        else if (!isempty(info->phys_port_name))
                 /* kernel provided front panel port name for multi-port PCI device */
                 l = strpcpyf(&s, l, "n%s", info->phys_port_name);
         else if (dev_port > 0)
@@ -485,7 +492,10 @@ static int dev_pci_slot(sd_device *dev, const LinkInfo *info, NetNames *names) {
                 l = strpcpyf(&s, l, "s%"PRIu32, hotplug_slot);
                 if (func > 0 || is_pci_multifunction(names->pcidev) > 0)
                         l = strpcpyf(&s, l, "f%u", func);
-                if (!isempty(info->phys_port_name))
+                if (naming_scheme_has(NAMING_SR_IOV_R) && info->vf_representor_id >= 0)
+                        /* For VF representor append 'r<VF_NUM>' and not phys_port_name */
+                        l = strpcpyf(&s, l, "r%d", info->vf_representor_id);
+                else if (!isempty(info->phys_port_name))
                         l = strpcpyf(&s, l, "n%s", info->phys_port_name);
                 else if (dev_port > 0)
                         l = strpcpyf(&s, l, "d%lu", dev_port);
@@ -1082,7 +1092,10 @@ static int get_link_info(sd_device *dev, LinkInfo *info) {
         if (r < 0 && r != -ENOENT)
                 return r;
 
-        (void) sd_device_get_sysattr_value(dev, "phys_port_name", &info->phys_port_name);
+        r = sd_device_get_sysattr_value(dev, "phys_port_name", &info->phys_port_name);
+        if (r >= 0)
+                /* Check if phys_port_name indicates virtual device representor */
+                (void) sscanf(info->phys_port_name, "pf%*uvf%d", &info->vf_representor_id);
 
         r = sd_device_get_sysattr_value(dev, "address", &s);
         if (r < 0 && r != -ENOENT)
@@ -1100,7 +1113,9 @@ static int builtin_net_id(UdevEvent *event, int argc, char *argv[], bool test) {
         sd_device *dev = ASSERT_PTR(ASSERT_PTR(event)->dev);
         const char *prefix;
         NetNames names = {};
-        LinkInfo info = {};
+        LinkInfo info = {
+                .vf_representor_id = -1,
+        };
         int r;
 
         r = get_link_info(dev, &info);