Merge branch 'netlink-add-display-hint-to-ynl'

Donald Hunter says:

====================
netlink: add display-hint to ynl

Add a display-hint property to the netlink schema, to be used by generic
netlink clients as hints about how to display attribute values.

A display-hint on an attribute definition is intended for letting a
client such as ynl know that, for example, a u32 should be rendered as
an ipv4 address. The display-hint enumeration includes a small number of
networking domain-specific value types.
====================

Link: https://lore.kernel.org/r/20230623201928.14275-1-donald.hunter@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/netlink/genetlink-c.yaml

@@ -195,6 +195,12 @@ properties:
                     description: Max length for a string or a binary attribute.
                     $ref: '#/$defs/len-or-define'
               sub-type: *attr-type
+              display-hint: &display-hint
+                description: |
+                  Optional format indicator that is intended only for choosing
+                  the right formatting mechanism when displaying values of this
+                  type.
+                enum: [ hex, mac, fddi, ipv4, ipv6, uuid ]
               # Start genetlink-c
               name-prefix:
                 type: string

Documentation/netlink/genetlink-legacy.yaml

@@ -119,7 +119,8 @@ properties:
               name:
                 type: string
               type:
-                enum: [ u8, u16, u32, u64, s8, s16, s32, s64, string ]
+                description: The netlink attribute type
+                enum: [ u8, u16, u32, u64, s8, s16, s32, s64, string, binary ]
               len:
                 $ref: '#/$defs/len-or-define'
               byte-order:
@@ -130,6 +131,12 @@ properties:
               enum:
                 description: Name of the enum type used for the attribute.
                 type: string
+              display-hint: &display-hint
+                description: |
+                  Optional format indicator that is intended only for choosing
+                  the right formatting mechanism when displaying values of this
+                  type.
+                enum: [ hex, mac, fddi, ipv4, ipv6, uuid ]
         # End genetlink-legacy
 
   attribute-sets:
@@ -179,6 +186,7 @@ properties:
               name:
                 type: string
               type: &attr-type
+                description: The netlink attribute type
                 enum: [ unused, pad, flag, binary, u8, u16, u32, u64, s32, s64,
                         string, nest, array-nest, nest-type-value ]
               doc:
@@ -226,6 +234,7 @@ properties:
                     description: Max length for a string or a binary attribute.
                     $ref: '#/$defs/len-or-define'
               sub-type: *attr-type
+              display-hint: *display-hint
               # Start genetlink-c
               name-prefix:
                 type: string

Documentation/netlink/genetlink.yaml

@@ -168,6 +168,12 @@ properties:
                     description: Max length for a string or a binary attribute.
                     $ref: '#/$defs/len-or-define'
               sub-type: *attr-type
+              display-hint: &display-hint
+                description: |
+                  Optional format indicator that is intended only for choosing
+                  the right formatting mechanism when displaying values of this
+                  type.
+                enum: [ hex, mac, fddi, ipv4, ipv6, uuid ]
 
       # Make sure name-prefix does not appear in subsets (subsets inherit naming)
       dependencies:

Documentation/netlink/specs/ovs_flow.yaml

@@ -33,6 +33,20 @@ definitions:
         name: n-bytes
         type: u64
         doc: Number of matched bytes.
+  -
+    name: ovs-key-ethernet
+    type: struct
+    members:
+      -
+        name: eth-src
+        type: binary
+        len: 6
+        display-hint: mac
+      -
+        name: eth-dst
+        type: binary
+        len: 6
+        display-hint: mac
   -
     name: ovs-key-mpls
     type: struct
@@ -49,10 +63,12 @@ definitions:
         name: ipv4-src
         type: u32
         byte-order: big-endian
+        display-hint: ipv4
       -
         name: ipv4-dst
         type: u32
         byte-order: big-endian
+        display-hint: ipv4
       -
         name: ipv4-proto
         type: u8
@@ -66,6 +82,45 @@ definitions:
         name: ipv4-frag
         type: u8
         enum: ovs-frag-type
+  -
+    name: ovs-key-ipv6
+    type: struct
+    members:
+      -
+        name: ipv6-src
+        type: binary
+        len: 16
+        byte-order: big-endian
+        display-hint: ipv6
+      -
+        name: ipv6-dst
+        type: binary
+        len: 16
+        byte-order: big-endian
+        display-hint: ipv6
+      -
+        name: ipv6-label
+        type: u32
+        byte-order: big-endian
+      -
+        name: ipv6-proto
+        type: u8
+      -
+        name: ipv6-tclass
+        type: u8
+      -
+        name: ipv6-hlimit
+        type: u8
+      -
+        name: ipv6-frag
+        type: u8
+  -
+    name: ovs-key-ipv6-exthdrs
+    type: struct
+    members:
+      -
+        name: hdrs
+        type: u16
   -
     name: ovs-frag-type
     name-prefix: ovs-frag-type-
@@ -129,6 +184,51 @@ definitions:
       -
         name: icmp-code
         type: u8
+  -
+    name: ovs-key-arp
+    type: struct
+    members:
+      -
+        name: arp-sip
+        type: u32
+        byte-order: big-endian
+      -
+        name: arp-tip
+        type: u32
+        byte-order: big-endian
+      -
+        name: arp-op
+        type: u16
+        byte-order: big-endian
+      -
+        name: arp-sha
+        type: binary
+        len: 6
+        display-hint: mac
+      -
+        name: arp-tha
+        type: binary
+        len: 6
+        display-hint: mac
+  -
+    name: ovs-key-nd
+    type: struct
+    members:
+      -
+        name: nd_target
+        type: binary
+        len: 16
+        byte-order: big-endian
+      -
+        name: nd-sll
+        type: binary
+        len: 6
+        display-hint: mac
+      -
+        name: nd-tll
+        type: binary
+        len: 6
+        display-hint: mac
   -
     name: ovs-key-ct-tuple-ipv4
     type: struct
@@ -345,6 +445,7 @@ attribute-sets:
           value of the OVS_FLOW_ATTR_KEY attribute. Optional for all
           requests. Present in notifications if the flow was created with this
           attribute.
+        display-hint: uuid
       -
         name: ufid-flags
         type: u32
@@ -374,6 +475,7 @@ attribute-sets:
       -
         name: ethernet
         type: binary
+        struct: ovs-key-ethernet
         doc: struct ovs_key_ethernet
       -
         name: vlan
@@ -390,6 +492,7 @@ attribute-sets:
       -
         name: ipv6
         type: binary
+        struct: ovs-key-ipv6
         doc: struct ovs_key_ipv6
       -
         name: tcp
@@ -410,10 +513,12 @@ attribute-sets:
       -
         name: arp
         type: binary
+        struct: ovs-key-arp
         doc: struct ovs_key_arp
       -
         name: nd
         type: binary
+        struct: ovs-key-nd
         doc: struct ovs_key_nd
       -
         name: skb-mark
@@ -457,6 +562,7 @@ attribute-sets:
       -
         name: ct-labels
         type: binary
+        display-hint: hex
         doc: 16-octet connection tracking label
       -
         name: ct-orig-tuple-ipv4
@@ -486,6 +592,7 @@ attribute-sets:
       -
         name: ipv6-exthdrs
         type: binary
+        struct: ovs-key-ipv6-exthdrs
         doc: struct ovs_key_ipv6_exthdr
   -
     name: action-attrs

tools/net/ynl/lib/nlspec.py

@@ -154,6 +154,9 @@ class SpecAttr(SpecElement):
         is_multi      bool, attr may repeat multiple times
         struct_name   string, name of struct definition
         sub_type      string, name of sub type
+        len           integer, optional byte length of binary types
+        display_hint  string, hint to help choose format specifier
+                      when displaying the value
     """
     def __init__(self, family, attr_set, yaml, value):
         super().__init__(family, yaml)
@@ -164,6 +167,8 @@ class SpecAttr(SpecElement):
         self.struct_name = yaml.get('struct')
         self.sub_type = yaml.get('sub-type')
         self.byte_order = yaml.get('byte-order')
+        self.len = yaml.get('len')
+        self.display_hint = yaml.get('display-hint')
 
 
 class SpecAttrSet(SpecElement):
@@ -229,12 +234,17 @@ class SpecStructMember(SpecElement):
         type        string, type of the member attribute
         byte_order  string or None for native byte order
         enum        string, name of the enum definition
+        len         integer, optional byte length of binary types
+        display_hint  string, hint to help choose format specifier
+                      when displaying the value
     """
     def __init__(self, family, yaml):
         super().__init__(family, yaml)
         self.type = yaml['type']
         self.byte_order = yaml.get('byte-order')
         self.enum = yaml.get('enum')
+        self.len = yaml.get('len')
+        self.display_hint = yaml.get('display-hint')
 
 
 class SpecStruct(SpecElement):

tools/net/ynl/lib/ynl.py

@@ -8,6 +8,8 @@ import socket
 import struct
 from struct import Struct
 import yaml
+import ipaddress
+import uuid
 
 from .nlspec import SpecFamily
 
@@ -105,6 +107,20 @@ class NlAttr:
                 else format.little
         return format.native
 
+    @classmethod
+    def formatted_string(cls, raw, display_hint):
+        if display_hint == 'mac':
+            formatted = ':'.join('%02x' % b for b in raw)
+        elif display_hint == 'hex':
+            formatted = bytes.hex(raw, ' ')
+        elif display_hint in [ 'ipv4', 'ipv6' ]:
+            formatted = format(ipaddress.ip_address(raw))
+        elif display_hint == 'uuid':
+            formatted = str(uuid.UUID(bytes=raw))
+        else:
+            formatted = raw
+        return formatted
+
     def as_scalar(self, attr_type, byte_order=None):
         format = self.get_format(attr_type, byte_order)
         return format.unpack(self.raw)[0]
@@ -124,10 +140,16 @@ class NlAttr:
         offset = 0
         for m in members:
             # TODO: handle non-scalar members
-            format = self.get_format(m.type, m.byte_order)
+            if m.type == 'binary':
-            decoded = format.unpack_from(self.raw, offset)
+                decoded = self.raw[offset:offset+m['len']]
-            offset += format.size
+                offset += m['len']
-            value[m.name] = decoded[0]
+            elif m.type in NlAttr.type_formats:
+                format = self.get_format(m.type, m.byte_order)
+                [ decoded ] = format.unpack_from(self.raw, offset)
+                offset += format.size
+            if m.display_hint:
+                decoded = self.formatted_string(decoded, m.display_hint)
+            value[m.name] = decoded
         return value
 
     def __repr__(self):
@@ -385,7 +407,7 @@ class YnlFamily(SpecFamily):
         elif attr["type"] == 'string':
             attr_payload = str(value).encode('ascii') + b'\x00'
         elif attr["type"] == 'binary':
-            attr_payload = value
+            attr_payload = bytes.fromhex(value)
         elif attr['type'] in NlAttr.type_formats:
             format = NlAttr.get_format(attr['type'], attr.byte_order)
             attr_payload = format.pack(int(value))
@@ -421,6 +443,8 @@ class YnlFamily(SpecFamily):
             decoded = attr.as_c_array(attr_spec.sub_type)
         else:
             decoded = attr.as_bin()
+            if attr_spec.display_hint:
+                decoded = NlAttr.formatted_string(decoded, attr_spec.display_hint)
         return decoded
 
     def _decode(self, attrs, space):