[mdns] update TxMessageHistory to use message length and CRCs (#11183)

This commit updates `TxMessageHistory` to track the message length
along with calculated CRC-16 and CRC-32 values of the message
content. This replaces the use of SHA256 hash, simplifying the code
and removing the dependency of the mDNS core module on the crypto
platform layer (and mbedtls).

src/core/net/mdns.cpp

@@ -30,6 +30,7 @@
 
 #if OPENTHREAD_CONFIG_MULTICAST_DNS_ENABLE
 
+#include "common/crc.hpp"
 #include "instance/instance.hpp"
 
 /**
@@ -4368,25 +4369,25 @@ Core::TxMessageHistory::TxMessageHistory(Instance &aInstance)
 
 void Core::TxMessageHistory::Clear(void)
 {
-    mHashEntries.Clear();
+    mMsgEntries.Clear();
     mTimer.Stop();
 }
 
 void Core::TxMessageHistory::Add(const Message &aMessage)
 {
-    Hash       hash;
-    HashEntry *entry;
+    MsgInfo   info;
+    MsgEntry *entry;
 
-    CalculateHash(aMessage, hash);
+    info.InitFrom(aMessage);
 
-    entry = mHashEntries.FindMatching(hash);
+    entry = mMsgEntries.FindMatching(info);
 
     if (entry == nullptr)
     {
-        entry = HashEntry::Allocate();
+        entry = MsgEntry::Allocate();
         OT_ASSERT(entry != nullptr);
-        entry->mHash = hash;
-        mHashEntries.Push(*entry);
+        entry->mInfo = info;
+        mMsgEntries.Push(*entry);
     }
 
     entry->mExpireTime = TimerMilli::GetNow() + kExpireInterval;
@@ -4395,28 +4396,32 @@ void Core::TxMessageHistory::Add(const Message &aMessage)
 
 bool Core::TxMessageHistory::Contains(const Message &aMessage) const
 {
-    Hash hash;
+    MsgInfo info;
 
-    CalculateHash(aMessage, hash);
-    return mHashEntries.ContainsMatching(hash);
+    info.InitFrom(aMessage);
+
+    return mMsgEntries.ContainsMatching(info);
 }
 
-void Core::TxMessageHistory::CalculateHash(const Message &aMessage, Hash &aHash)
+void Core::TxMessageHistory::MsgInfo::InitFrom(const Message &aMessage)
 {
-    Crypto::Sha256 sha256;
+    OffsetRange offsetRange;
 
-    sha256.Start();
-    sha256.Update(aMessage, /* aOffset */ 0, aMessage.GetLength());
-    sha256.Finish(aHash);
+    offsetRange.InitFromMessageFullLength(aMessage);
+
+    Clear();
+    mMsgLength = aMessage.GetLength();
+    mCrc16     = CrcCalculator<uint16_t>(kCrc16AnsiPolynomial).Feed(aMessage, offsetRange);
+    mCrc32     = CrcCalculator<uint32_t>(kCrc32AnsiPolynomial).Feed(aMessage, offsetRange);
 }
 
 void Core::TxMessageHistory::HandleTimer(void)
 {
     NextFireTime nextTime;
 
-    mHashEntries.RemoveAndFreeAllMatching(ExpireChecker(nextTime.GetNow()));
+    mMsgEntries.RemoveAndFreeAllMatching(ExpireChecker(nextTime.GetNow()));
 
-    for (const HashEntry &entry : mHashEntries)
+    for (const MsgEntry &entry : mMsgEntries)
     {
         nextTime.UpdateIfEarlier(entry.mExpireTime);
     }

src/core/net/mdns.hpp

@@ -49,9 +49,7 @@
 #include "common/locator.hpp"
 #include "common/owned_ptr.hpp"
 #include "common/owning_list.hpp"
-#include "common/retain_ptr.hpp"
 #include "common/timer.hpp"
-#include "crypto/sha256.hpp"
 #include "net/dns_types.hpp"
 
 #if OPENTHREAD_CONFIG_MULTICAST_DNS_AUTO_ENABLE_ON_INFRA_IF && !OPENTHREAD_CONFIG_BORDER_ROUTING_ENABLE
@@ -1432,24 +1430,29 @@ private:
     private:
         static constexpr uint32_t kExpireInterval = TimeMilli::SecToMsec(10); // in msec
 
-        typedef Crypto::Sha256::Hash Hash;
-
-        struct HashEntry : public LinkedListEntry<HashEntry>, public Heap::Allocatable<HashEntry>
+        struct MsgInfo : public Clearable<MsgInfo>, public Equatable<MsgInfo>
         {
-            bool Matches(const Hash &aHash) const { return aHash == mHash; }
-            bool Matches(const ExpireChecker &aExpireChecker) const { return mExpireTime <= aExpireChecker.mNow; }
+            void InitFrom(const Message &aMessage);
 
-            HashEntry *mNext;
-            Hash       mHash;
-            TimeMilli  mExpireTime;
+            uint16_t mMsgLength;
+            uint16_t mCrc16;
+            uint32_t mCrc32;
         };
 
-        static void CalculateHash(const Message &aMessage, Hash &aHash);
+        struct MsgEntry : public LinkedListEntry<MsgEntry>, public Heap::Allocatable<MsgEntry>
+        {
+            bool Matches(const MsgInfo &aInfo) const { return mInfo == aInfo; }
+            bool Matches(const ExpireChecker &aExpireChecker) const { return mExpireTime <= aExpireChecker.mNow; }
+
+            MsgEntry *mNext;
+            MsgInfo   mInfo;
+            TimeMilli mExpireTime;
+        };
 
         using TxMsgHistoryTimer = TimerMilliIn<Core, &Core::HandleTxMessageHistoryTimer>;
 
-        OwningList<HashEntry> mHashEntries;
-        TxMsgHistoryTimer     mTimer;
+        OwningList<MsgEntry> mMsgEntries;
+        TxMsgHistoryTimer    mTimer;
     };
 
     // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -