[cli] add new command neighbor linkquality (#8508)

This commit adds a new CLI command `neighbor linkqulaity` which prints
the collected link quality info (such as frame error rate, message
error rate, average/last RSSI) for all neighbors.

src/cli/README.md

@@ -2061,6 +2061,19 @@ Get the NAT64 translator packet and error counters.
 Done
 ```
 
+### neighbor linkquality
+
+Print link quality info for all neighbors.
+
+```bash
+> neighbor linkquality
+| RLOC16 | Extended MAC     | Frame Error | Msg Error | Avg RSS | Last RSS | Age   |
++--------+------------------+-------------+-----------+---------+----------+-------+
+| 0xe800 | 9e2fa4e1b84f92db |      0.00 % |    0.00 % |     -46 |      -48 |     1 |
+| 0xc001 | 0ad7ed6beaa6016d |      4.67 % |    0.08 % |     -68 |      -72 |    10 |
+Done
+```
+
 ### neighbor list
 
 List RLOC16 of neighbors.

src/cli/cli.cpp

@@ -1768,9 +1768,11 @@ template <> otError Interpreter::Process<Cmd("channel")>(Arg aArgs[])
                 OutputLine("count: %lu", ToUlong(otChannelMonitorGetSampleCount(GetInstancePtr())));
 
                 OutputLine("occupancies:");
+
                 for (uint8_t channel = 0; channel < channelNum; channel++)
                 {
-                    uint32_t occupancy = 0;
+                    uint16_t               occupancy;
+                    PercentageStringBuffer stringBuffer;
 
                     if (!((1UL << channel) & channelMask))
                     {
@@ -1779,11 +1781,10 @@ template <> otError Interpreter::Process<Cmd("channel")>(Arg aArgs[])
 
                     occupancy = otChannelMonitorGetChannelOccupancy(GetInstancePtr(), channel);
 
-                    OutputFormat("ch %u (0x%04lx) ", channel, ToUlong(occupancy));
-                    occupancy = (occupancy * 10000) / 0xffff;
-                    OutputLine("%2u.%02u%% busy", static_cast<uint16_t>(occupancy / 100),
-                               static_cast<uint16_t>(occupancy % 100));
+                    OutputLine("ch %u (0x%04x) %6s%% busy", channel, occupancy,
+                               PercentageToString(occupancy, stringBuffer));
                 }
+
                 OutputNewLine();
             }
         }
@@ -4987,6 +4988,31 @@ template <> otError Interpreter::Process<Cmd("neighbor")>(Arg aArgs[])
 
         OutputNewLine();
     }
+    else if (aArgs[0] == "linkquality")
+    {
+        static const char *const kLinkQualityTableTitles[] = {
+            "RLOC16", "Extended MAC", "Frame Error", "Msg Error", "Avg RSS", "Last RSS", "Age",
+        };
+
+        static const uint8_t kLinkQualityTableColumnWidths[] = {
+            8, 18, 13, 11, 9, 10, 7,
+        };
+
+        OutputTableHeader(kLinkQualityTableTitles, kLinkQualityTableColumnWidths);
+
+        while (otThreadGetNextNeighborInfo(GetInstancePtr(), &iterator, &neighborInfo) == OT_ERROR_NONE)
+        {
+            PercentageStringBuffer stringBuffer;
+
+            OutputFormat("| 0x%04x | ", neighborInfo.mRloc16);
+            OutputExtAddress(neighborInfo.mExtAddress);
+            OutputFormat(" | %9s %% ", PercentageToString(neighborInfo.mFrameErrorRate, stringBuffer));
+            OutputFormat("| %7s %% ", PercentageToString(neighborInfo.mMessageErrorRate, stringBuffer));
+            OutputFormat("| %7d ", neighborInfo.mAverageRssi);
+            OutputFormat("| %8d ", neighborInfo.mLastRssi);
+            OutputLine("| %5lu |", ToUlong(neighborInfo.mAge));
+        }
+    }
     else
     {
         error = OT_ERROR_INVALID_ARGS;

src/cli/cli_output.cpp

@@ -261,6 +261,18 @@ void Output::OutputDnsTxtData(const uint8_t *aTxtData, uint16_t aTxtDataLength)
 
     OutputFormat("]");
 }
+
+const char *Output::PercentageToString(uint16_t aValue, PercentageStringBuffer &aBuffer)
+{
+    uint32_t     scaledValue = aValue;
+    StringWriter writer(aBuffer.mChars, sizeof(aBuffer.mChars));
+
+    scaledValue = (scaledValue * 10000) / 0xffff;
+    writer.Append("%u.%02u", static_cast<uint16_t>(scaledValue / 100), static_cast<uint16_t>(scaledValue % 100));
+
+    return aBuffer.mChars;
+}
+
 #endif // OPENTHREAD_FTD || OPENTHREAD_MTD
 
 void Output::OutputFormatV(const char *aFormat, va_list aArguments) { mImplementer.OutputV(aFormat, aArguments); }

src/cli/cli_output.hpp

@@ -204,7 +204,7 @@ public:
     otInstance *GetInstancePtr(void) { return mInstance; }
 
     /**
-     * This structure represents a buffer which is sued when converting a `uint64` value to string in decimal format.
+     * This structure represents a buffer which is used when converting a `uint64` value to string in decimal format.
      *
      */
     struct Uint64StringBuffer
@@ -440,6 +440,32 @@ public:
      */
     void OutputDnsTxtData(const uint8_t *aTxtData, uint16_t aTxtDataLength);
 
+    /**
+     * This structure represents a buffer which is used when converting an encoded rate value to percentage string.
+     *
+     */
+    struct PercentageStringBuffer
+    {
+        static constexpr uint16_t kSize = 7; ///< Size of a buffer
+
+        char mChars[kSize]; ///< Char array (do not access the array directly).
+    };
+
+    /**
+     * This static method converts an encoded value to a percentage representation.
+     *
+     * The encoded @p aValue is assumed to be linearly scaled such that `0` maps to 0% and `0xffff` maps to 100%.
+     *
+     * The resulting string provides two decimal accuracy, e.g., "100.00", "0.00", "75.37".
+     *
+     * @param[in] aValue   The encoded percentage value to convert.
+     * @param[in] aBuffer  A buffer to allocate the string from.
+     *
+     * @returns A pointer to the start of the string (null-terminated) representation of @p aValue.
+     *
+     */
+    static const char *PercentageToString(uint16_t aValue, PercentageStringBuffer &aBuffer);
+
 #endif // OPENTHREAD_FTD || OPENTHREAD_MTD
 
     /**