feat: full NFSv4.2 server and client in pure Go

Assisted-by: GLM 5.3 Flash

internal/nfs4/ops41.go

@@ -0,0 +1,118 @@
+// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
+// SPDX-License-Identifier: MIT
+
+// The codecs of the remaining NFSv4.1 operations: the parent lookups, the
+// attribute comparisons, the lock owner release and the session binding
+// family.
+
+package nfs4
+
+import (
+	"sourcedock.dev/petrbalvin/nfs/internal/xdr"
+)
+
+// Connection direction and binding values of the CREATE_SESSION and
+// BIND_CONN_TO_SESSION channel directory, RFC 8881 section 2.10.1.
+const (
+	Cdfc4Fore       = 1
+	Cdfc4Back       = 2
+	Cdfc4ForeOrBoth = 3
+	Cdfc4BackOrBoth = 7
+
+	Cdfs4Fore  = 1
+	Cdfs4Back  = 2
+	Cdfs4Both  = 3
+	Cdfs4Arrow = 4
+)
+
+// AppendLookupp appends the LOOKUPP argop, which carries no arguments.
+func AppendLookupp(b []byte) []byte {
+	return xdr.AppendUint32(b, OpLookupp)
+}
+
+// AppendPutPubfh appends the PUTPUBFH argop, which carries no arguments.
+func AppendPutPubfh(b []byte) []byte {
+	return xdr.AppendUint32(b, OpPutPubfh)
+}
+
+// AppendVerifyArgs appends the VERIFY argop: the attributes the file must
+// carry for the compound to proceed. NVERIFY shares the shape and demands
+// the opposite.
+func AppendVerifyArgs(b []byte, request Bitmap, a Attrs) []byte {
+	b = xdr.AppendUint32(b, OpVerify)
+	return AppendFattr(b, request, a)
+}
+
+// AppendNverifyArgs appends the NVERIFY argop: the attributes the file
+// must not carry.
+func AppendNverifyArgs(b []byte, request Bitmap, a Attrs) []byte {
+	b = xdr.AppendUint32(b, OpNverify)
+	return AppendFattr(b, request, a)
+}
+
+// AppendReleaseLockOwnerArgs appends the RELEASE_LOCKOWNER argop: the
+// client whose lock owner dies and the owner itself.
+func AppendReleaseLockOwnerArgs(b []byte, clientid uint64, owner []byte) []byte {
+	b = xdr.AppendUint32(b, OpReleaseLockOwner)
+	b = xdr.AppendUint64(b, clientid)
+	return xdr.AppendVarOpaque(b, owner)
+}
+
+// AppendDelegReturnArgs appends the DELEGRETURN argop: the stateid of the
+// delegation the client gives back.
+func AppendDelegReturnArgs(b []byte, st Stateid) []byte {
+	b = xdr.AppendUint32(b, OpDelegReturn)
+	return st.Append(b)
+}
+
+// AppendBackchannelCtlArgs appends the BACKCHANNEL_CTL argop: the program
+// number of the back channel the client runs.
+func AppendBackchannelCtlArgs(b []byte, program uint32) []byte {
+	b = xdr.AppendUint32(b, OpBackchannelCtl)
+	return xdr.AppendUint32(b, program)
+}
+
+// AppendBindConnToSessionArgs appends the BIND_CONN_TO_SESSION argop of
+// RFC 7863: the session, the direction the connection should serve and
+// the RDMA mode flag.
+func AppendBindConnToSessionArgs(b []byte, id SessionID, dir uint32, rdma bool) []byte {
+	b = xdr.AppendUint32(b, OpBindConnToSession)
+	b = append(b, id[:]...)
+	b = xdr.AppendUint32(b, dir)
+	return xdr.AppendBool(b, rdma)
+}
+
+// AppendBindConnToSessionRes appends the result: the session and the
+// direction the server granted.
+func AppendBindConnToSessionRes(b []byte, id SessionID, dir uint32) []byte {
+	b = append(b, id[:]...)
+	return xdr.AppendUint32(b, dir)
+}
+
+// AppendFreeStateidArgs appends the FREE_STATEID argop: the lock stateid
+// the client retires.
+func AppendFreeStateidArgs(b []byte, st Stateid) []byte {
+	b = xdr.AppendUint32(b, OpFreeStateid)
+	return st.Append(b)
+}
+
+// AppendTestStateidArgs appends the TEST_STATEID argop: the stateids the
+// client asks about.
+func AppendTestStateidArgs(b []byte, sts []Stateid) []byte {
+	b = xdr.AppendUint32(b, OpTestStateid)
+	b = xdr.AppendUint32(b, uint32(len(sts)))
+	for _, st := range sts {
+		b = st.Append(b)
+	}
+	return b
+}
+
+// AppendTestStateidRes appends the result: one status per stateid, in the
+// order the arguments named them.
+func AppendTestStateidRes(b []byte, statuses []uint32) []byte {
+	b = xdr.AppendUint32(b, uint32(len(statuses)))
+	for _, s := range statuses {
+		b = xdr.AppendUint32(b, s)
+	}
+	return b
+}