Remove the concept from "first" from TSIG.

The sign() and validate() routines took a "first" parameter, which
indicated that this message was the first in a multi-message sequence.
This isn't needed, as it's identical to "not (ctx and multi)".

Remove the parameter from both, as well as the now-unneeded field in the
message object and message.from_wire() parameter.

4 files changed, 9 insertions, 19 deletions

diff --git a/dns/message.py b/dns/message.py
index a7c6bfa..9fd3d77 100644
--- a/dns/message.py
+++ b/dns/message.py
@@ -116,7 +116,6 @@ class Message:
         self.origin = None
         self.tsig_ctx = None
         self.multi = False
-        self.first = True
         self.index = {}
 
     @property
@@ -445,8 +444,7 @@ class Message:
                                             int(time.time()),
                                             self.request_mac,
                                             tsig_ctx,
-                                            multi,
-                                            tsig_ctx is None)
+                                            multi)
             self.tsig.clear()
             self.tsig.add(new_tsig)
             r.add_rrset(dns.renderer.ADDITIONAL, self.tsig)
@@ -820,8 +818,7 @@ class _WireReader:
                                       self.message.request_mac,
                                       rr_start,
                                       self.message.tsig_ctx,
-                                      self.message.multi,
-                                      self.message.first)
+                                      self.message.multi)
                 self.message.tsig = dns.rrset.from_rdata(absolute_name, 0, rd)
             else:
                 rrset = self.message.find_rrset(section, name,
@@ -865,7 +862,7 @@ class _WireReader:
 
 
 def from_wire(wire, keyring=None, request_mac=b'', xfr=False, origin=None,
-              tsig_ctx=None, multi=False, first=True,
+              tsig_ctx=None, multi=False,
               question_only=False, one_rr_per_rrset=False,
               ignore_trailing=False, raise_on_truncation=False):
     """Convert a DNS wire format message into a message
@@ -890,9 +887,6 @@ def from_wire(wire, keyring=None, request_mac=b'', xfr=False, origin=None,
     *multi*, a ``bool``, should be set to ``True`` if this message is
     part of a multiple message sequence.
 
-    *first*, a ``bool``, should be set to ``True`` if this message is
-    stand-alone, or the first message in a multi-message sequence.
-
     *question_only*, a ``bool``.  If ``True``, read only up to
     the end of the question section.
 
@@ -930,7 +924,6 @@ def from_wire(wire, keyring=None, request_mac=b'', xfr=False, origin=None,
         message.origin = origin
         message.tsig_ctx = tsig_ctx
         message.multi = multi
-        message.first = first
 
     reader = _WireReader(wire, initialize_message, question_only,
                          one_rr_per_rrset, ignore_trailing)
diff --git a/dns/message.pyi b/dns/message.pyi
index 76af040..8b83a78 100644
--- a/dns/message.pyi
+++ b/dns/message.pyi
@@ -35,7 +35,6 @@ class Message:
         self.tsig_ctx = None
         self.had_tsig = False
         self.multi = False
-        self.first = True
         self.index : Dict[Tuple[rrset.RRset, name.Name, int, int, Union[int,str], int], rrset.RRset] = {}
 
     def is_response(self, other : Message) -> bool:
@@ -45,7 +44,7 @@ def from_text(a : str, idna_codec : Optional[name.IDNACodec] = None) -> Message:
     ...
 
 def from_wire(wire, keyring : Optional[Dict[name.Name,bytes]] = None, request_mac = b'', xfr=False, origin=None,
-              tsig_ctx : Optional[hmac.HMAC] = None, multi=False, first=True,
+              tsig_ctx : Optional[hmac.HMAC] = None, multi=False,
               question_only=False, one_rr_per_rrset=False,
               ignore_trailing=False) -> Message:
     ...
diff --git a/dns/query.py b/dns/query.py
index ae4258a..3404b91 100644
--- a/dns/query.py
+++ b/dns/query.py
@@ -920,7 +920,6 @@ def xfr(where, zone, rdtype=dns.rdatatype.AXFR, rdclass=dns.rdataclass.IN,
             origin = None
             oname = zone
         tsig_ctx = None
-        first = True
         while not done:
             (_, mexpiration) = _compute_times(timeout)
             if mexpiration is None or \
@@ -937,13 +936,11 @@ def xfr(where, zone, rdtype=dns.rdatatype.AXFR, rdclass=dns.rdataclass.IN,
             r = dns.message.from_wire(wire, keyring=q.keyring,
                                       request_mac=q.mac, xfr=True,
                                       origin=origin, tsig_ctx=tsig_ctx,
-                                      multi=True, first=first,
-                                      one_rr_per_rrset=is_ixfr)
+                                      multi=True, one_rr_per_rrset=is_ixfr)
             rcode = r.rcode()
             if rcode != dns.rcode.NOERROR:
                 raise TransferError(rcode)
             tsig_ctx = r.tsig_ctx
-            first = False
             answer_index = 0
             if soa_rrset is None:
                 if not r.answer or r.answer[0].name != oname:
diff --git a/dns/tsig.py b/dns/tsig.py
index 2780c3c..e4a2520 100644
--- a/dns/tsig.py
+++ b/dns/tsig.py
@@ -86,7 +86,7 @@ BADTRUNC = 22
 
 
 def sign(wire, keyname, rdata, secret, time=None, request_mac=None,
-         ctx=None, multi=False, first=True):
+         ctx=None, multi=False):
     """Return a (tsig_rdata, mac, ctx) tuple containing the HMAC TSIG rdata
     for the input parameters, the HMAC MAC calculated by applying the
     TSIG signature algorithm, and the TSIG digest context.
@@ -95,6 +95,7 @@ def sign(wire, keyname, rdata, secret, time=None, request_mac=None,
     @raises NotImplementedError: I{algorithm} is not supported
     """
 
+    first = not (ctx and multi)
     (algorithm_name, digestmod) = get_algorithm(rdata.algorithm)
     if first:
         ctx = hmac.new(secret, digestmod=digestmod)
@@ -136,7 +137,7 @@ def sign(wire, keyname, rdata, secret, time=None, request_mac=None,
 
 
 def validate(wire, keyname, rdata, secret, now, request_mac, tsig_start,
-             ctx=None, multi=False, first=True):
+             ctx=None, multi=False):
     """Validate the specified TSIG rdata against the other input parameters.
 
     @raises FormError: The TSIG is badly formed.
@@ -164,7 +165,7 @@ def validate(wire, keyname, rdata, secret, now, request_mac, tsig_start,
     if abs(rdata.time_signed - now) > rdata.fudge:
         raise BadTime
     (our_rdata, ctx) = sign(new_wire, keyname, rdata, secret, None, request_mac,
-                            ctx, multi, first)
+                            ctx, multi)
     if our_rdata.mac != rdata.mac:
         raise BadSignature
     return ctx