WebRTC bridge component

 - This component is specifically designed to exchange messages between signaling and streaming planes of the WebRTC
 - For example, if we want to implement only the streaming part of the webrtc and
get signaling messages relayed to it, another device can implement signaling and relay those messages to streaming plane

Author: vikramdattu

esp_port/components/webrtc_bridge/CMakeLists.txt

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+set(srcs "src/webrtc_bridge.c")
+
+set(requires mqtt esp_webrtc_utils)
+
+idf_component_register(SRCS "${srcs}"
+                       REQUIRES ${requires}
+                       INCLUDE_DIRS "include")
+
+if (ENABLE_SIGNALLING_ONLY)
+    add_definitions(-DENABLE_SIGNALLING_ONLY)
+elseif (ENABLE_STREAMING_ONLY)
+    add_definitions(-DENABLE_STREAMING_ONLY)
+endif ()

esp_port/components/webrtc_bridge/Kconfig.projbuild

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+menu "WebRTC Bridge Config"
+    choice WEBRTC_BRIDGE_TYPE
+        bool "Bridge to use between streaming and signalling device"
+        default ESP_WEBRTC_BRIDGE_MQTT
+        default ESP_WEBRTC_BRIDGE_HOSTED if IDF_TARGET_ESP32P4
+        default ESP_WEBRTC_BRIDGE_HOSTED if IDF_TARGET_ESP32C6
+        help
+            Bus interface to be used for communication with the host
+
+        config ESP_WEBRTC_BRIDGE_HOSTED
+            bool "Use hosted bridge"
+            help
+                Relay messages using existing esp_hosted communication line
+                Direct dependancy on `ESP_HOSTED_ENABLED`
+
+        config ESP_WEBRTC_BRIDGE_MQTT
+            bool "Use MQTT bridge"
+            help
+                Relay messages using by subscribing and publishing to MQTT broker
+    endchoice
+endmenu

esp_port/components/webrtc_bridge/README.md

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+# WebRTC Bridge
+- The communication bridge between Signalling and Streaming part of the WebRTC.
+- When running with [split mode](../../README.md#split_mode), we need a bridge between Signalling device and the Streaming device running respective parts of the WebRTC.
+- By default, i.e., the bridge used is esp_hosted. It is also possible to use MQTT as the bridge.

esp_port/components/webrtc_bridge/idf_component.yml

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+description: webrtc_bridge
+version: "0.0.1"
+
+dependencies:
+  esp_webrtc_utils:
+    path: ../esp_webrtc_utils
+    version: "*"
+  # espressif/esp_hosted:
+  #   override_path: ../esp_hosted
+  #   version: "*"

esp_port/components/webrtc_bridge/include/webrtc_bridge.h

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+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Function pointer type for WebRTC bridge message callback
+ *
+ * @param data Pointer to the received message data
+ * @param len Length of the received message data
+ */
+typedef void (*webrtc_bridge_msg_cb_t) (const void *data, int len);
+
+/**
+ * @brief Start the webrtc bridge
+ */
+void webrtc_bridge_start(void);
+
+/**
+ * @brief Send message via webrtc bridge
+ *
+ * @param data pointer to the data to send
+ * @param len length of the data to send
+ *
+ * @note the data is freed by the webrtc bridge, hence do not free it in the caller
+ */
+void webrtc_bridge_send_message(const char *data, int len);
+
+/**
+ * @brief Register a message handler for the webrtc bridge
+ *
+ * @param handler function pointer to the message handler
+ */
+void webrtc_bridge_register_handler(webrtc_bridge_msg_cb_t handler);
+
+#ifdef __cplusplus
+}
+#endif