[PATCH net-next v2 1/2] selftests: openvswitch: add vlan() and encap() flow string parsing

[Minxi Hou <houminxi@gmail.com>]

Extend the ovs-dpctl.py flow parser to support vlan() and encap()
match strings.  vlan() accepts tci=, vid=, pcp=, and cfi=
parameters and generates the OVS_KEY_ATTR_VLAN attribute with a TCI
value in network byte order.  encap() parses nested flow strings
and returns OVS_KEY_ATTR_ENCAP with inner key attributes as a
recursive NLA container.

The encap nla_map type is changed from "none" to "nested" so that
pyroute2 recursively encodes the inner flow key attributes.  The
VLAN nla_map type is changed from "uint16" to "be16" to match the
kernel's big-endian wire format.

Signed-off-by: Minxi Hou <houminxi@gmail.com>
---
v1 -> v2: rebase to latest net-next/main, drop --base=auto

 .../selftests/net/openvswitch/ovs-dpctl.py    | 190 +++++++++++++++++-
 1 file changed, 188 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
index 848f61fdcee0..317be7878937 100644
--- a/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
+++ b/tools/testing/selftests/net/openvswitch/ovs-dpctl.py
@@ -901,11 +901,11 @@ class ovskey(nla):
     nla_flags = NLA_F_NESTED
     nla_map = (
         ("OVS_KEY_ATTR_UNSPEC", "none"),
-        ("OVS_KEY_ATTR_ENCAP", "none"),
+        ("OVS_KEY_ATTR_ENCAP", "nested"),
         ("OVS_KEY_ATTR_PRIORITY", "uint32"),
         ("OVS_KEY_ATTR_IN_PORT", "uint32"),
         ("OVS_KEY_ATTR_ETHERNET", "ethaddr"),
-        ("OVS_KEY_ATTR_VLAN", "uint16"),
+        ("OVS_KEY_ATTR_VLAN", "be16"),
         ("OVS_KEY_ATTR_ETHERTYPE", "be16"),
         ("OVS_KEY_ATTR_IPV4", "ovs_key_ipv4"),
         ("OVS_KEY_ATTR_IPV6", "ovs_key_ipv6"),
@@ -1636,6 +1636,180 @@ class ovskey(nla):
     class ovs_key_mpls(nla):
         fields = (("lse", ">I"),)
 
+    # 802.1Q CFI (Canonical Format Indicator) bit, always set for Ethernet
+    _VLAN_CFI_MASK = 0x1000
+    _MAX_ENCAP_DEPTH = 4
+    _encap_depth = 0  # single-threaded usage assumed
+
+    @staticmethod
+    def _parse_vlan_from_flowstr(flowstr):
+        """Parse vlan(tci=X) or vlan(vid=X[,pcp=Y,cfi=Z]) from flowstr.
+
+        Returns (remaining_flowstr, key_tci, mask_tci).
+        TCI values use standard bit layout (VID bits 0-11,
+        CFI bit 12, PCP bits 13-15); byte order conversion to
+        big-endian happens in pyroute2 be16 NLA serialization.
+        The mask covers only the fields the caller specified:
+        vid -> 0x0FFF, pcp -> 0xE000, cfi -> 0x1000, tci -> 0xFFFF.
+
+        The tci= key sets the raw TCI bitfield (no CFI validation) to allow
+        non-Ethernet use cases.  Use cfi=1 for standard Ethernet VLAN matching.
+        """
+        tci = 0
+        mask = 0
+        has_tci = False
+        has_vid = has_pcp = has_cfi = False
+        _tci_mix_err = "vlan(): 'tci' cannot be mixed " \
+                       "with 'vid'/'pcp'/'cfi'"
+        first = True
+        while True:
+            flowstr = flowstr.lstrip()
+            if not flowstr:
+                raise ValueError("vlan(): missing ')'")
+            if flowstr[0] == ')':
+                break
+            if not first:
+                flowstr = flowstr[1:]  # skip ','
+                if not flowstr:
+                    raise ValueError("vlan(): missing ')' after trailing comma")
+                flowstr = flowstr.lstrip()
+                if flowstr and flowstr[0] == ')':
+                    break
+                if flowstr and flowstr[0] == ',':
+                    raise ValueError(
+                        "vlan(): empty or extra comma in field list")
+            first = False
+
+            eq = flowstr.find('=')
+            if eq == -1:
+                raise ValueError("vlan(): expected key=value, got '%s'" % flowstr)
+            key = flowstr[:eq].strip()
+            flowstr = flowstr[eq + 1:]
+
+            end = flowstr.find(',')
+            end2 = flowstr.find(')')
+            if end == -1 or (end2 != -1 and end2 < end):
+                end = end2
+            val = flowstr[:end].strip()
+            flowstr = flowstr[end:]
+
+            if not val:
+                raise ValueError("vlan(): empty value for key '%s'" % key)
+            try:
+                v = int(val, 16) if val.startswith(('0x', '0X')) else int(val)
+            except ValueError:
+                raise ValueError("vlan(): invalid value '%s' for key '%s'" %
+                                 (val, key))
+
+            if key == 'tci':
+                if has_tci:
+                    raise ValueError("vlan(): duplicate 'tci'")
+                if has_vid or has_pcp or has_cfi:
+                    raise ValueError(_tci_mix_err)
+                if v > 0xFFFF or v < 0:
+                    raise ValueError("vlan(): tci=0x%x out of range" % v)
+                tci = v
+                mask = 0xFFFF
+                has_tci = True
+            elif key == 'vid':
+                if has_tci:
+                    raise ValueError(_tci_mix_err)
+                if has_vid:
+                    raise ValueError("vlan(): duplicate 'vid'")
+                if v < 0 or v > 0xFFF:
+                    raise ValueError("vlan(): vid=%d out of range (0-4095)" % v)
+                tci |= v
+                mask |= 0x0FFF
+                has_vid = True
+            elif key == 'pcp':
+                if has_tci:
+                    raise ValueError(_tci_mix_err)
+                if has_pcp:
+                    raise ValueError("vlan(): duplicate 'pcp'")
+                if v < 0 or v > 7:
+                    raise ValueError("vlan(): pcp=%d out of range (0-7)" % v)
+                tci |= (v & 0x7) << 13
+                mask |= 0xE000
+                has_pcp = True
+            elif key == 'cfi':
+                if has_tci:
+                    raise ValueError(_tci_mix_err)
+                if has_cfi:
+                    raise ValueError("vlan(): duplicate 'cfi'")
+                if v != 1:
+                    raise ValueError("vlan(): cfi must be 1 for Ethernet")
+                tci |= ovskey._VLAN_CFI_MASK
+                mask |= ovskey._VLAN_CFI_MASK
+                has_cfi = True
+            else:
+                raise ValueError("vlan(): unknown key '%s'" % key)
+
+        flowstr = flowstr[1:]  # skip ')'
+        # Catch immediate '))' (user error).  A ')' after ',' is consumed
+        # by parse()'s strspn(flowstr, "), ") inter-field separator stripping.
+        if flowstr.lstrip().startswith(')'):
+            raise ValueError("vlan(): unmatched ')'")
+        # parse() strips trailing ',', ')', ' ' as inter-field separators,
+        # so we do not need to call strspn here.
+
+        if mask == 0:
+            raise ValueError("vlan(): no fields specified, "
+                             "use vlan(vid=X[,pcp=Y,cfi=Z]) or vlan(tci=X)")
+        if not has_tci:
+            tci |= ovskey._VLAN_CFI_MASK
+            mask |= ovskey._VLAN_CFI_MASK
+        return flowstr, tci, mask
+
+    @staticmethod
+    def _parse_encap_from_flowstr(flowstr):
+        """Parse encap(inner_flow) from flowstr.
+
+        Returns (remaining_flowstr, inner_key_dict, inner_mask_dict)
+        where each dict has an 'attrs' key for recursive NLA encoding.
+        Parenthesis-depth tracking handles nested encap() calls but not
+        quoted strings containing literal parentheses.
+        """
+        if ovskey._encap_depth >= ovskey._MAX_ENCAP_DEPTH:
+            raise ValueError("encap(): max nesting depth %d exceeded" %
+                             ovskey._MAX_ENCAP_DEPTH)
+        try:
+            ovskey._encap_depth += 1
+            depth = 1
+            end = -1
+            for i, c in enumerate(flowstr):
+                if c == '(':
+                    depth += 1
+                elif c == ')':
+                    depth -= 1
+                    if depth < 0:
+                        raise ValueError("encap(): unmatched ')' at position %d" % i)
+                    if depth == 0:
+                        end = i
+                        break
+
+            if end == -1:
+                if depth > 1:
+                    raise ValueError("encap(): missing ')' at end")
+                raise ValueError("encap(): missing closing ')'")
+
+            inner_str = flowstr[:end].strip()
+            if not inner_str:
+                raise ValueError("encap(): empty inner flow")
+
+            flowstr = flowstr[end + 1:]
+            if flowstr.lstrip().startswith(')'):
+                raise ValueError("encap(): unmatched ')' after encap()")
+            # parse() strips trailing ',', ')', ' ' as inter-field separators,
+            # so we do not need to call strspn here.
+
+            inner_key = ovskey()
+            inner_mask = ovskey()
+            inner_key.parse(inner_str, inner_mask)
+
+            return flowstr, inner_key, inner_mask
+        finally:
+            ovskey._encap_depth -= 1
+
     def parse(self, flowstr, mask=None):
         for field in (
             ("OVS_KEY_ATTR_PRIORITY", "skb_priority", intparse),
@@ -1657,6 +1831,16 @@ class ovskey(nla):
                 "eth_type",
                 lambda x: intparse(x, "0xffff"),
             ),
+            (
+                "OVS_KEY_ATTR_VLAN",
+                "vlan",
+                ovskey._parse_vlan_from_flowstr,
+            ),
+            (
+                "OVS_KEY_ATTR_ENCAP",
+                "encap",
+                ovskey._parse_encap_from_flowstr,
+            ),
             (
                 "OVS_KEY_ATTR_IPV4",
                 "ipv4",
@@ -1794,6 +1978,8 @@ class ovskey(nla):
                 True,
             ),
             ("OVS_KEY_ATTR_ETHERNET", None, None, False, False),
+            ("OVS_KEY_ATTR_VLAN", "vlan", "0x%04x", lambda x: False, True),
+            ("OVS_KEY_ATTR_ENCAP", None, None, False, False),
             (
                 "OVS_KEY_ATTR_ETHERTYPE",
                 "eth_type",
-- 
2.53.0