[cli] Update command "br scan" to allow network interface selection for

mDNS binding. Within the OTBR practice application, the BR host will have several interfaces. When users want to discover the border router using mDNS, they will need to choose the specific interface. This change introduces a new option for the CLI command `br scan`. User can now specify a network interface using the syntax `br scan --netif <network interface>. The chosen interface will be used for mDNS binding through socket options.
ZhangLe2016 · Apr 12, 2024 · 688867a · 688867a
1 parent 6269cc5
commit 688867a
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Showing 4 changed files with 23 additions and 9 deletions.
diff --git a/include/commissioner/error.hpp b/include/commissioner/error.hpp
@@ -161,6 +161,11 @@ enum class ErrorCode : int
      * The error is out of the address space of OT Commissioner.
      */
     kUnknown = 19,
+
+    /**
+     * The error occurs when attempting to bind a network interface to an mDNS socket."
+     */
+    kSocketBindError = 20,
 };
 
 /**

diff --git a/src/app/cli/interpreter.cpp b/src/app/cli/interpreter.cpp
@@ -1433,28 +1433,30 @@ Interpreter::Value Interpreter::ProcessBr(const Expression &aExpr)
         nlohmann::json                            baJson;
         char                                      mdnsSendBuffer[kMdnsBufferSize];
 
-        if (mContext.mCommandKeys.size() == 2 && mContext.mCommandKeys[0] == "--timeout")
-        {
+        auto it = std::find(mContext.mCommandKeys.begin(), mContext.mCommandKeys.end(), "--timeout");
+
+        if (it != mContext.mCommandKeys.end()) {
             try
             {
-                scanTimeout = stol(mContext.mCommandKeys[1]);
+              scanTimeout = stol(mContext.mCommandKeys[std::distance(mContext.mCommandKeys.begin(), it) + 1]);
             } catch (...)
             {
-                ExitNow(value = ERROR_INVALID_ARGS("Imparsable timeout value '{}'", aExpr[3]));
+                ExitNow(value = ERROR_INVALID_ARGS("Imparsable timeout value '{}'", mContext.mCommandKeys[std::distance(mContext.mCommandKeys.begin(), it)]));
             }
         }
 
-        if (mContext.mCommandKeys.size() == 2 && mContext.mCommandKeys[0] == "--netif")
-        {
-            netIf = mContext.mCommandKeys[1];
+        it = std::find(mContext.mCommandKeys.begin(), mContext.mCommandKeys.end(), "--netif");
+
+        if (it != mContext.mCommandKeys.end()) {
+            netIf = mContext.mCommandKeys[std::distance(mContext.mCommandKeys.begin(), it) + 1];
         }
 
         // Open IPv4 mDNS socket
         mdnsSocket = mdns_socket_open_ipv4();
         VerifyOrExit(mdnsSocket >= 0, value = ERROR_IO_ERROR("failed to open mDNS IPv4 socket"));
 
-        if (netIf != "" && setsockopt(mdnsSocket, SOL_SOCKET, SO_BINDTODEVICE, &netIf[0], sizeof(netIf)) < 0) {
-          ExitNow(value = ERROR_IO_ERROR("failed to bind network interface: {}", netIf));
+        if (!netIf.empty() && setsockopt(mdnsSocket, SOL_SOCKET, SO_BINDTODEVICE, netIf.c_str(), netIf.size()) < 0) {
+            ExitNow(value = ERROR_SOCKET_BIND_ERROR("failed to bind network interface: {}", netIf));
         }
 
         fdgMdnsSocket.mFD = mdnsSocket;

diff --git a/src/common/error.cpp b/src/common/error.cpp
@@ -86,6 +86,8 @@ static std::string ErrorCodeToString(ErrorCode code)
         return "REGISTRY_ERROR";
     case ErrorCode::kUnknown:
         return "UNKNOWN";
+    case ErrorCode::kSocketBindError:
+        return "SOCKET_BIND_ERROR";
 
     default:
         VerifyOrDie(false);

diff --git a/src/common/error_macros.hpp b/src/common/error_macros.hpp
@@ -137,5 +137,10 @@
     {                                                                          \
         ErrorCode::kUnknown, fmt::format(FMT_STRING((aFormat)), ##__VA_ARGS__) \
     }
+#define ERROR_SOCKET_BIND_ERROR(aFormat, ...)                                            \
+    Error                                                                                \
+    {                                                                                    \
+        ErrorCode::kSocketBindError, fmt::format(FMT_STRING((aFormat)), ##__VA_ARGS__)   \
+    }
 
 #endif // ERROR_MACROS_HPP_