Basic implementation of HELLO

Directory.Packages.props

@@ -19,7 +19,7 @@
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
     <PackageVersion Include="Microsoft.IdentityModel.Protocols.OpenIdConnect" Version="7.5.1" />
     <PackageVersion Include="Microsoft.IdentityModel.Validators" Version="7.5.1" />
-    <PackageVersion Include="StackExchange.Redis" Version="2.6.80" />
+    <PackageVersion Include="StackExchange.Redis" Version="2.7.33" />
     <PackageVersion Include="System.IdentityModel.Tokens.Jwt" Version="7.5.1" />
     <PackageVersion Include="System.Interactive.Async" Version="6.0.1" />
   </ItemGroup>

libs/common/ConvertUtils.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT license.
 
 using System;
+using System.Diagnostics;
 
 namespace Garnet.common
 {
@@ -53,5 +54,38 @@ public static void MakeUpperCase(Span<byte> command)
                 if (c > 96 && c < 123)
                     c -= 32;
         }
+
+        /// <summary>
+        /// Check if two byte spans are equal, where right is an all-upper-case span, ignoring case if there are ASCII bytes.
+        /// </summary>
+        /// <param name="left"></param>
+        /// <param name="right"></param>
+        /// <returns></returns>
+        public static bool EqualsUpperCaseSpanIgnoringCase(this ReadOnlySpan<byte> left, ReadOnlySpan<byte> right)
+        {
+            if (left.SequenceEqual(right))
+                return true;
+            if (left.Length != right.Length)
+                return false;
+            for (int i = 0; i < left.Length; i++)
+            {
+                var b1 = left[i];
+                var b2 = right[i];
+
+                // Debug assert that b2 is an upper case letter 'A'-'Z'
+                Debug.Assert(b2 is >= 65 and <= 90);
+
+                if (b1 == b2 || b1 - 32 == b2)
+                    continue;
+                return false;
+            }
+            return true;
+        }
+
+        /// <summary>
+        /// Check if two byte spans are equal, where right is an all-upper-case span, ignoring case if there are ASCII bytes.
+        /// </summary>
+        public static bool EqualsUpperCaseSpanIgnoringCase(this Span<byte> left, ReadOnlySpan<byte> right)
+            => EqualsUpperCaseSpanIgnoringCase((ReadOnlySpan<byte>)left, right);
     }
 }

libs/common/RespWriteUtils.cs

@@ -14,6 +14,21 @@ namespace Garnet.common
     /// </summary>
     public static unsafe class RespWriteUtils
     {
+        /// <summary>
+        /// Write map length
+        /// </summary>
+        public static bool WriteMapLength(int len, ref byte* curr, byte* end)
+        {
+            int numDigits = NumUtils.NumDigits(len);
+            int totalLen = 1 + numDigits + 2;
+            if (totalLen > (int)(end - curr))
+                return false;
+            *curr++ = (byte)'%';
+            NumUtils.IntToBytes(len, numDigits, ref curr);
+            WriteNewline(ref curr);
+            return true;
+        }
+
         /// <summary>
         /// Write array length
         /// </summary>

libs/server/Metrics/Info/GarnetInfoMetrics.cs

@@ -46,7 +46,6 @@ private void PopulateServerInfo(StoreWrapper storeWrapper)
             serverInfo =
             [
                 new("garnet_version", storeWrapper.version),
-                new("garnet_mode", storeWrapper.serverOptions.EnableCluster ? "cluster" : "standalone"),
                 new("os", Environment.OSVersion.ToString()),
                 new("processor_count", Environment.ProcessorCount.ToString()),
                 new("arch_bits", Environment.Is64BitProcess ? "64" : "32"),
@@ -56,7 +55,8 @@ private void PopulateServerInfo(StoreWrapper storeWrapper)
                 new("monitor_freq", storeWrapper.serverOptions.MetricsSamplingFrequency.ToString()),
                 new("latency_monitor", storeWrapper.serverOptions.LatencyMonitor ? "enabled" : "disabled"),
                 new("run_id", storeWrapper.run_id),
-                new("redis_version", storeWrapper.redisProtocolVersion)
+                new("redis_version", storeWrapper.redisProtocolVersion),
+                new("redis_mode", storeWrapper.serverOptions.EnableCluster ? "cluster" : "standalone"),
             ];
         }
 

libs/server/Resp/AdminCommands.cs

@@ -71,12 +71,12 @@ private bool ProcessAdminCommands<TGarnetApi>(RespCommand command, ReadOnlySpan<
                         {
                             if (username.IsEmpty)
                             {
-                                while (!RespWriteUtils.WriteError("WRONGPASS Invalid password"u8, ref dcurr, dend))
+                                while (!RespWriteUtils.WriteError(CmdStrings.RESP_WRONGPASS_INVALID_PASSWORD, ref dcurr, dend))
                                     SendAndReset();
                             }
                             else
                             {
-                                while (!RespWriteUtils.WriteError("WRONGPASS Invalid username/password combination"u8, ref dcurr, dend))
+                                while (!RespWriteUtils.WriteError(CmdStrings.RESP_WRONGPASS_INVALID_USERNAME_PASSWORD, ref dcurr, dend))
                                     SendAndReset();
                             }
                         }
@@ -250,8 +250,16 @@ private bool ProcessAdminCommands<TGarnetApi>(RespCommand command, ReadOnlySpan<
             {
                 if (count == 0)
                 {
-                    while (!RespWriteUtils.WriteDirect(CmdStrings.RESP_PONG, ref dcurr, dend))
-                        SendAndReset();
+                    if (isSubscriptionSession && respProtocolVersion == 2)
+                    {
+                        while (!RespWriteUtils.WriteDirect(CmdStrings.SUSCRIBE_PONG, ref dcurr, dend))
+                            SendAndReset();
+                    }
+                    else
+                    {
+                        while (!RespWriteUtils.WriteDirect(CmdStrings.RESP_PONG, ref dcurr, dend))
+                            SendAndReset();
+                    }
                 }
                 else if (count == 1)
                 {
@@ -270,6 +278,74 @@ private bool ProcessAdminCommands<TGarnetApi>(RespCommand command, ReadOnlySpan<
                     errorCmd = "ping";
                 }
             }
+            else if (command == RespCommand.HELLO)
+            {
+                int? respProtocolVersion = null;
+                ReadOnlySpan<byte> authUsername = default, authPassword = default;
+                string clientName = null;
+
+                if (count > 0)
+                {
+                    var ptr = recvBufferPtr + readHead;
+                    int localRespProtocolVersion;
+                    if (!RespReadUtils.ReadIntWithLengthHeader(out localRespProtocolVersion, ref ptr, recvBufferPtr + bytesRead))
+                        return false;
+                    readHead = (int)(ptr - recvBufferPtr);
+
+                    respProtocolVersion = localRespProtocolVersion;
+                    count--;
+                    while (count > 0)
+                    {
+                        var param = GetCommand(bufSpan, out bool success1);
+                        if (!success1) return false;
+                        count--;
+                        if (param.EqualsUpperCaseSpanIgnoringCase(CmdStrings.AUTH))
+                        {
+                            if (count < 2)
+                            {
+                                if (!DrainCommands(bufSpan, count))
+                                    return false;
+                                count = 0;
+                                errorFlag = true;
+                                errorCmd = nameof(RespCommand.HELLO);
+                                break;
+                            }
+                            authUsername = GetCommand(bufSpan, out success1);
+                            if (!success1) return false;
+                            count--;
+                            authPassword = GetCommand(bufSpan, out success1);
+                            if (!success1) return false;
+                            count--;
+                        }
+                        else if (param.EqualsUpperCaseSpanIgnoringCase(CmdStrings.SETNAME))
+                        {
+                            if (count < 1)
+                            {
+                                if (!DrainCommands(bufSpan, count))
+                                    return false;
+                                count = 0;
+                                errorFlag = true;
+                                errorCmd = nameof(RespCommand.HELLO);
+                                break;
+                            }
+
+                            var arg = GetCommand(bufSpan, out success1);
+                            if (!success1) return false;
+                            count--;
+                            clientName = Encoding.ASCII.GetString(arg);
+                        }
+                        else
+                        {
+                            if (!DrainCommands(bufSpan, count))
+                                return false;
+                            count = 0;
+                            errorFlag = true;
+                            errorCmd = nameof(RespCommand.HELLO);
+                        }
+                    }
+                }
+                if (!errorFlag) ProcessHelloCommand(respProtocolVersion, authUsername, authPassword, clientName);
+            }
             else if (command is RespCommand.CLUSTER or RespCommand.MIGRATE or RespCommand.FAILOVER or RespCommand.REPLICAOF or RespCommand.SECONDARYOF)
             {
                 if (clusterSession == null)
@@ -488,6 +564,77 @@ private bool ProcessAdminCommands<TGarnetApi>(RespCommand command, ReadOnlySpan<
             return true;
         }
 
+        void ProcessHelloCommand(int? respProtocolVersion, ReadOnlySpan<byte> username, ReadOnlySpan<byte> password, string clientName)
+        {
+            if (respProtocolVersion != null)
+            {
+                if (respProtocolVersion.Value != 2)
+                {
+                    while (!RespWriteUtils.WriteError(CmdStrings.RESP_ERR_UNSUPPORTED_PROTOCOL_VERSION, ref dcurr, dend))
+                        SendAndReset();
+                    return;
+                }
+
+                this.respProtocolVersion = respProtocolVersion.Value;
+            }
+
+            if (username != default)
+            {
+                if (!this.AuthenticateUser(username, password))
+                {
+                    if (username.IsEmpty)
+                    {
+                        while (!RespWriteUtils.WriteError(CmdStrings.RESP_WRONGPASS_INVALID_PASSWORD, ref dcurr, dend))
+                            SendAndReset();
+                    }
+                    else
+                    {
+                        while (!RespWriteUtils.WriteError(CmdStrings.RESP_WRONGPASS_INVALID_USERNAME_PASSWORD, ref dcurr, dend))
+                            SendAndReset();
+                    }
+                    return;
+                }
+            }
+
+            if (clientName != null)
+            {
+                this.clientName = clientName;
+            }
+
+            (string, string)[] helloResult =
+                [
+                    ("server", "redis"),
+                    ("version", storeWrapper.redisProtocolVersion),
+                    ("garnet_version", storeWrapper.version),
+                    ("proto", $"{this.respProtocolVersion}"),
+                    ("id", "63"),
+                    ("mode", storeWrapper.serverOptions.EnableCluster ? "cluster" : "standalone"),
+                    ("role", storeWrapper.serverOptions.EnableCluster && storeWrapper.clusterProvider.IsReplica() ? "replica" : "master"),
+                ];
+
+            if (this.respProtocolVersion == 2)
+            {
+                while (!RespWriteUtils.WriteArrayLength(helloResult.Length * 2 + 2, ref dcurr, dend))
+                    SendAndReset();
+            }
+            else
+            {
+                while (!RespWriteUtils.WriteMapLength(helloResult.Length + 1, ref dcurr, dend))
+                    SendAndReset();
+            }
+            for (int i = 0; i < helloResult.Length; i++)
+            {
+                while (!RespWriteUtils.WriteAsciiBulkString(helloResult[i].Item1, ref dcurr, dend))
+                    SendAndReset();
+                while (!RespWriteUtils.WriteAsciiBulkString(helloResult[i].Item2, ref dcurr, dend))
+                    SendAndReset();
+            }
+            while (!RespWriteUtils.WriteAsciiBulkString("modules", ref dcurr, dend))
+                SendAndReset();
+            while (!RespWriteUtils.WriteArrayLength(0, ref dcurr, dend))
+                SendAndReset();
+        }
+
         /// <summary>
         /// Performs @admin command group permission checks for the current user and the given command.
         /// (NOTE: This function is temporary until per-command permissions are implemented)

libs/server/Resp/BasicCommands.cs

@@ -888,8 +888,16 @@ private bool NetworkAppend<TGarnetApi>(byte* ptr, ref TGarnetApi storageApi)
         /// </summary>
         private bool NetworkPING()
         {
-            while (!RespWriteUtils.WriteDirect(CmdStrings.RESP_PONG, ref dcurr, dend))
-                SendAndReset();
+            if (isSubscriptionSession && respProtocolVersion == 2)
+            {
+                while (!RespWriteUtils.WriteDirect(CmdStrings.SUSCRIBE_PONG, ref dcurr, dend))
+                    SendAndReset();
+            }
+            else
+            {
+                while (!RespWriteUtils.WriteDirect(CmdStrings.RESP_PONG, ref dcurr, dend))
+                    SendAndReset();
+            }
             return true;
         }
 

libs/server/Resp/CmdStrings.cs

@@ -31,6 +31,7 @@ static partial class CmdStrings
         public static ReadOnlySpan<byte> ACL => "ACL"u8;
         public static ReadOnlySpan<byte> AUTH => "AUTH"u8;
         public static ReadOnlySpan<byte> auth => "auth"u8;
+        public static ReadOnlySpan<byte> SETNAME => "SETNAME"u8;
         public static ReadOnlySpan<byte> INFO => "INFO"u8;
         public static ReadOnlySpan<byte> info => "info"u8;
         public static ReadOnlySpan<byte> DOCS => "DOCS"u8;
@@ -47,6 +48,7 @@ static partial class CmdStrings
         public static ReadOnlySpan<byte> HELP => "HELP"u8;
         public static ReadOnlySpan<byte> help => "help"u8;
         public static ReadOnlySpan<byte> PING => "PING"u8;
+        public static ReadOnlySpan<byte> HELLO => "HELLO"u8;
         public static ReadOnlySpan<byte> TIME => "TIME"u8;
         public static ReadOnlySpan<byte> RESET => "RESET"u8;
         public static ReadOnlySpan<byte> reset => "reset"u8;
@@ -80,12 +82,13 @@ static partial class CmdStrings
         public static ReadOnlySpan<byte> RESP_RETURN_VAL_1 => ":1\r\n"u8;
         public static ReadOnlySpan<byte> RESP_RETURN_VAL_0 => ":0\r\n"u8;
         public static ReadOnlySpan<byte> RESP_RETURN_VAL_N1 => ":-1\r\n"u8;
+        public static ReadOnlySpan<byte> SUSCRIBE_PONG => "*2\r\n$4\r\npong\r\n$0\r\n\r\n"u8;
         public static ReadOnlySpan<byte> RESP_PONG => "+PONG\r\n"u8;
         public static ReadOnlySpan<byte> RESP_EMPTY => "$0\r\n\r\n"u8;
         public static ReadOnlySpan<byte> RESP_QUEUED => "+QUEUED\r\n"u8;
 
         /// <summary>
-        /// Simple error respone strings, i.e. these are of the form "-errorString\r\n"
+        /// Simple error response strings, i.e. these are of the form "-errorString\r\n"
         /// </summary>
         public static ReadOnlySpan<byte> RESP_ERR_NOAUTH => "NOAUTH Authentication required."u8;
         public static ReadOnlySpan<byte> RESP_ERR_WRONG_TYPE => "WRONGTYPE Operation against a key holding the wrong kind of value."u8;
@@ -119,6 +122,10 @@ static partial class CmdStrings
         public static ReadOnlySpan<byte> RESP_ERR_GENERIC_INDEX_OUT_RANGE => "ERR index out of range"u8;
         public static ReadOnlySpan<byte> RESP_ERR_GENERIC_SELECT_INVALID_INDEX => "ERR invalid database index."u8;
         public static ReadOnlySpan<byte> RESP_ERR_GENERIC_SELECT_CLUSTER_MODE => "ERR SELECT is not allowed in cluster mode"u8;
+        public static ReadOnlySpan<byte> RESP_ERR_UNSUPPORTED_PROTOCOL_VERSION => "ERR Unsupported protocol version"u8;
+        public static ReadOnlySpan<byte> RESP_WRONGPASS_INVALID_PASSWORD => "WRONGPASS Invalid password"u8;
+        public static ReadOnlySpan<byte> RESP_WRONGPASS_INVALID_USERNAME_PASSWORD => "WRONGPASS Invalid username/password combination"u8;
+
 
         /// <summary>
         /// Response string templates

libs/server/Resp/RespCommand.cs

@@ -123,6 +123,7 @@ public enum RespCommand : byte
         FORCEGC = 0x3B,
         FAILOVER = 0x3C,
         ACL = 0x3D,
+        HELLO = 0x3E,
 
         // Custom commands
         CustomTxn = 0x29,
@@ -1048,6 +1049,10 @@ static RespCommand MatchedNone(RespServerSession session, int oldReadHead)
             {
                 return (RespCommand.PING, 0);
             }
+            else if (command.SequenceEqual(CmdStrings.HELLO))
+            {
+                return (RespCommand.HELLO, 0);
+            }
             else if (command.SequenceEqual(CmdStrings.CLUSTER))
             {
                 return (RespCommand.CLUSTER, 0);

libs/server/Resp/RespCommandsInfo.json

@@ -1422,6 +1422,21 @@
     ],
     "SubCommands": null
   },
+  {
+    "Command": "HELLO",
+    "ArrayCommand": null,
+    "Name": "HELLO",
+    "IsInternal": false,
+    "Arity": -1,
+    "Flags": "Fast, Loading, NoAuth, NoScript, Stale, AllowBusy",
+    "FirstKey": 0,
+    "LastKey": 0,
+    "Step": 0,
+    "AclCategories": "Connection, Fast",
+    "Tips": null,
+    "KeySpecifications": null,
+    "SubCommands": null
+  },
   {
     "Command": "Hash",
     "ArrayCommand": 7,

libs/server/Resp/RespServerSession.cs

@@ -104,6 +104,10 @@ internal sealed unsafe partial class RespServerSession : ServerSessionBase
         /// </summary>
         CustomObjectCommand currentCustomObjectCommand = null;
 
+
+        int respProtocolVersion = 2;
+        string clientName = null;
+
         public RespServerSession(
             INetworkSender networkSender,
             StoreWrapper storeWrapper,