webrtc: allow to specify ice-servers on command line

RELEASE.md

@@ -8,6 +8,7 @@
 - http: add `/control` to provide simple JS interface to live edit camera settings
 - http: change `/option` to accept `device=`, `key=`, and `value=`
 - device: show stddev estimates to measure frame pacing
+- webrtc: allow to specify `--webrtc-ice_servers=` on command line
 
 ## Variants
 

cmd/camera-streamer/opts.c

@@ -131,6 +131,8 @@ option_t all_options[] = {
 
   DEFINE_OPTION_DEFAULT(rtsp, port, uint, "8554", "Set the RTSP server port (default: 8854)."),
 
+  DEFINE_OPTION_PTR(webrtc, ice_servers, list, "Specify ICE servers: [(stun|turn|turns)(:|://)][username:password@]hostname[:port][?transport=udp|tcp|tls)]."),
+
   DEFINE_OPTION_DEFAULT(log, debug, bool, "1", "Enable debug logging."),
   DEFINE_OPTION_DEFAULT(log, verbose, bool, "1", "Enable verbose logging."),
   DEFINE_OPTION_DEFAULT(log, stats, uint, "1", "Print statistics every duration."),

output/webrtc/webrtc.cc

@@ -9,9 +9,12 @@ extern "C" {
 #include "util/opts/log.h"
 #include "util/opts/fourcc.h"
 #include "util/opts/control.h"
+#include "util/opts/opts.h"
 #include "device/buffer.h"
 };
 
+#include "util/opts/helpers.hh"
+
 #ifdef USE_LIBDATACHANNEL
 
 #include <string>
@@ -37,7 +40,7 @@ static std::mutex webrtc_clients_lock;
 static const auto webrtc_client_lock_timeout = 3 * 1000ms;
 static const auto webrtc_client_max_json_body = 10 * 1024;
 static const auto webrtc_client_video_payload_type = 102; // H264
-static const rtc::Configuration webrtc_configuration = {
+static rtc::Configuration webrtc_configuration = {
   // .iceServers = { rtc::IceServer("stun:stun.l.google.com:19302") },
   .disableAutoNegotiation = true
 };
@@ -390,6 +393,10 @@ extern "C" void http_webrtc_offer(http_worker_t *worker, FILE *stream)
 
 extern "C" int webrtc_server(webrtc_options_t *options)
 {
+  for (const auto &ice_server : str_split(options->ice_servers, OPTION_VALUE_LIST_SEP_CHAR)) {
+    webrtc_configuration.iceServers.push_back(rtc::IceServer(ice_server));
+  }
+
   buffer_lock_register_check_streaming(&video_lock, webrtc_h264_needs_buffer);
   buffer_lock_register_notify_buffer(&video_lock, webrtc_h264_capture);
   options->running = true;

output/webrtc/webrtc.h

@@ -2,11 +2,14 @@
 
 #include <stdio.h>
 
+#define WEBRTC_OPTIONS_LENGTH 4096
+
 typedef struct http_worker_s http_worker_t;
 
 typedef struct webrtc_options_s {
   bool running;
   bool disabled;
+  char ice_servers[WEBRTC_OPTIONS_LENGTH];
 } webrtc_options_t;
 
 // WebRTC

util/opts/helpers.hh

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#include <sstream>
+
+inline std::vector<std::string> str_split(const std::string& in, const char seperator)
+{
+  std::vector<std::string> output;
+  std::istringstream stream(in);
+  for (std::string s; std::getline(stream, s, seperator); ) {
+    output.push_back(s);
+  }
+  return output;
+}

util/opts/opts.h

@@ -26,6 +26,7 @@ typedef struct options_s {
   const char *description;
 } option_t;
 
+#define OPTION_VALUE_LIST_SEP_CHAR ';'
 #define OPTION_VALUE_LIST_SEP ";"
 
 #define OPTION_FORMAT_uint   "%u"