Adds support for the SVCB/HTTPS ohttp parameter. (#1072)

dns/rdtypes/svcbbase.py

@@ -35,6 +35,7 @@ class ParamKey(dns.enum.IntEnum):
     ECH = 5
     IPV6HINT = 6
     DOHPATH = 7
+    OHTTP = 8
 
     @classmethod
     def _maximum(cls):
@@ -396,6 +397,36 @@ def to_wire(self, file, origin=None):  # pylint: disable=W0613
         file.write(self.ech)
 
 
+@dns.immutable.immutable
+class OHTTPParam(Param):
+    # We don't ever expect to instantiate this class, but we need
+    # a from_value() and a from_wire_parser(), so we just return None
+    # from the class methods when things are OK.
+
+    @classmethod
+    def emptiness(cls):
+        return Emptiness.ALWAYS
+
+    @classmethod
+    def from_value(cls, value):
+        if value is None or value == "":
+            return None
+        else:
+            raise ValueError("ohttp with non-empty value")
+
+    def to_text(self):
+        raise NotImplementedError  # pragma: no cover
+
+    @classmethod
+    def from_wire_parser(cls, parser, origin=None):  # pylint: disable=W0613
+        if parser.remaining() != 0:
+            raise dns.exception.FormError
+        return None
+
+    def to_wire(self, file, origin=None):  # pylint: disable=W0613
+        raise NotImplementedError  # pragma: no cover
+
+
 _class_for_key = {
     ParamKey.MANDATORY: MandatoryParam,
     ParamKey.ALPN: ALPNParam,
@@ -404,6 +435,7 @@ def to_wire(self, file, origin=None):  # pylint: disable=W0613
     ParamKey.IPV4HINT: IPv4HintParam,
     ParamKey.ECH: ECHParam,
     ParamKey.IPV6HINT: IPv6HintParam,
+    ParamKey.OHTTP: OHTTPParam,
 }
 
 

tests/example

@@ -259,6 +259,10 @@ svcb01                  SVCB (
 100 foo.com. mandatory="alpn,port" alpn="h2,h3" no-default-alpn port="12345"
 ech="abcd" ipv4hint=1.2.3.4,4.3.2.1 ipv6hint=1::2,3::4 key12345="foo"
 )
+svcb02                  SVCB 16 foo.example.org. alpn="foo\\,bar,h2"
+svcb03                  SVCB 16 foo.example.org. alpn=foo\092,bar,h2
+svcb04                  SVCB 16 foo.example.org. dohpath=/dns-query{?dns}
+svcb05                  SVCB 16 foo.example.org. ohttp
 https01                 HTTPS 0 svc
 https02                 HTTPS 1 . port=8002 ech="abcd"
-resinfo                 RESINFO qnamemin exterr=15,16,17 infourl=https://resolver.example.com/guide
+resinfo                 RESINFO qnamemin exterr=15,16,17 infourl=https://resolver.example.com/guide

tests/example1.good

@@ -133,6 +133,10 @@ srv01 3600 IN SRV 0 0 0 .
 srv02 3600 IN SRV 65535 65535 65535 old-slow-box.example.com.
 sshfp1 3600 IN SSHFP 1 1 aa549bfe898489c02d1715d97d79c57ba2fa76ab
 svcb01 3600 IN SVCB 100 foo.com. mandatory="alpn,port" alpn="h2,h3" no-default-alpn port="12345" ipv4hint="1.2.3.4,4.3.2.1" ech="abcd" ipv6hint="1::2,3::4" key12345="foo"
+svcb02 3600 IN SVCB 16 foo.example.org. alpn="foo\\,bar,h2"
+svcb03 3600 IN SVCB 16 foo.example.org. alpn="foo\\,bar,h2"
+svcb04 3600 IN SVCB 16 foo.example.org. dohpath="/dns-query{?dns}"
+svcb05 3600 IN SVCB 16 foo.example.org. ohttp
 t 301 IN A 73.80.65.49
 tlsa1 3600 IN TLSA 3 1 1 a9cdf989b504fe5dca90c0d2167b6550570734f7c763e09fdf88904e06157065
 tlsa2 3600 IN TLSA 1 0 1 efddf0d915c7bdc5782c0881e1b2a95ad099fbdd06d7b1f77982d9364338d955

tests/example2.good

@@ -133,6 +133,10 @@ srv01.example. 3600 IN SRV 0 0 0 .
 srv02.example. 3600 IN SRV 65535 65535 65535 old-slow-box.example.com.
 sshfp1.example. 3600 IN SSHFP 1 1 aa549bfe898489c02d1715d97d79c57ba2fa76ab
 svcb01.example. 3600 IN SVCB 100 foo.com. mandatory="alpn,port" alpn="h2,h3" no-default-alpn port="12345" ipv4hint="1.2.3.4,4.3.2.1" ech="abcd" ipv6hint="1::2,3::4" key12345="foo"
+svcb02.example. 3600 IN SVCB 16 foo.example.org. alpn="foo\\,bar,h2"
+svcb03.example. 3600 IN SVCB 16 foo.example.org. alpn="foo\\,bar,h2"
+svcb04.example. 3600 IN SVCB 16 foo.example.org. dohpath="/dns-query{?dns}"
+svcb05.example. 3600 IN SVCB 16 foo.example.org. ohttp
 t.example. 301 IN A 73.80.65.49
 tlsa1.example. 3600 IN TLSA 3 1 1 a9cdf989b504fe5dca90c0d2167b6550570734f7c763e09fdf88904e06157065
 tlsa2.example. 3600 IN TLSA 1 0 1 efddf0d915c7bdc5782c0881e1b2a95ad099fbdd06d7b1f77982d9364338d955

tests/example3.good

@@ -133,6 +133,10 @@ srv01 3600 IN SRV 0 0 0 .
 srv02 3600 IN SRV 65535 65535 65535 old-slow-box.example.com.
 sshfp1 3600 IN SSHFP 1 1 aa549bfe898489c02d1715d97d79c57ba2fa76ab
 svcb01 3600 IN SVCB 100 foo.com. mandatory="alpn,port" alpn="h2,h3" no-default-alpn port="12345" ipv4hint="1.2.3.4,4.3.2.1" ech="abcd" ipv6hint="1::2,3::4" key12345="foo"
+svcb02 3600 IN SVCB 16 foo.example.org. alpn="foo\\,bar,h2"
+svcb03 3600 IN SVCB 16 foo.example.org. alpn="foo\\,bar,h2"
+svcb04 3600 IN SVCB 16 foo.example.org. dohpath="/dns-query{?dns}"
+svcb05 3600 IN SVCB 16 foo.example.org. ohttp
 t 301 IN A 73.80.65.49
 tlsa1 3600 IN TLSA 3 1 1 a9cdf989b504fe5dca90c0d2167b6550570734f7c763e09fdf88904e06157065
 tlsa2 3600 IN TLSA 1 0 1 efddf0d915c7bdc5782c0881e1b2a95ad099fbdd06d7b1f77982d9364338d955

tests/example4.good

@@ -134,6 +134,10 @@ srv01 3600 IN SRV 0 0 0 .
 srv02 3600 IN SRV 65535 65535 65535 old-slow-box.example.com.
 sshfp1 3600 IN SSHFP 1 1 aa549bfe898489c02d1715d97d79c57ba2fa76ab
 svcb01 3600 IN SVCB 100 foo.com. mandatory="alpn,port" alpn="h2,h3" no-default-alpn port="12345" ipv4hint="1.2.3.4,4.3.2.1" ech="abcd" ipv6hint="1::2,3::4" key12345="foo"
+svcb02 3600 IN SVCB 16 foo.example.org. alpn="foo\\,bar,h2"
+svcb03 3600 IN SVCB 16 foo.example.org. alpn="foo\\,bar,h2"
+svcb04 3600 IN SVCB 16 foo.example.org. dohpath="/dns-query{?dns}"
+svcb05 3600 IN SVCB 16 foo.example.org. ohttp
 t 301 IN A 73.80.65.49
 tlsa1 3600 IN TLSA 3 1 1 a9cdf989b504fe5dca90c0d2167b6550570734f7c763e09fdf88904e06157065
 tlsa2 3600 IN TLSA 1 0 1 efddf0d915c7bdc5782c0881e1b2a95ad099fbdd06d7b1f77982d9364338d955