From c24becf2152e131882af98d5e0810d13162aefc6 Mon Sep 17 00:00:00 2001
From: Wiebe Cazemier <wiebe@halfgaar.net>
Date: Sun, 3 Jul 2022 16:23:08 +0200
Subject: [PATCH] Allow for any websocket protocol containing mqtt

---
 iowrapper.cpp |  5 +++--
 utils.cpp     | 11 +++++++----
 utils.h       |  4 ++--
 3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/iowrapper.cpp b/iowrapper.cpp
index efaed66..51f4171 100644
--- a/iowrapper.cpp
+++ b/iowrapper.cpp
@@ -371,7 +371,8 @@ ssize_t IoWrapper::readWebsocketAndOrSsl(int fd, void *buf, size_t nbytes, IoWra
                 {
                     std::string websocketKey;
                     int websocketVersion;
-                    if (parseHttpHeader(websocketPendingBytes, websocketKey, websocketVersion))
+                    std::string subprotocol;
+                    if (parseHttpHeader(websocketPendingBytes, websocketKey, websocketVersion, subprotocol))
                     {
                         if (websocketKey.empty())
                             throw BadHttpRequest("No websocket key specified.");
@@ -380,7 +381,7 @@ ssize_t IoWrapper::readWebsocketAndOrSsl(int fd, void *buf, size_t nbytes, IoWra
 
                         const std::string acceptString = generateWebsocketAcceptString(websocketKey);
 
-                        std::string answer = generateWebsocketAnswer(acceptString);
+                        std::string answer = generateWebsocketAnswer(acceptString, subprotocol);
                         parentClient->writeText(answer);
                         websocketState = WebsocketState::Upgrading;
                         websocketPendingBytes.reset();
diff --git a/utils.cpp b/utils.cpp
index 828fbef..bcd6f21 100644
--- a/utils.cpp
+++ b/utils.cpp
@@ -348,7 +348,7 @@ bool isPowerOfTwo(int n)
     return (n != 0) && (n & (n - 1)) == 0;
 }
 
-bool parseHttpHeader(CirBuf &buf, std::string &websocket_key, int &websocket_version)
+bool parseHttpHeader(CirBuf &buf, std::string &websocket_key, int &websocket_version, std::string &subprotocol)
 {
     const std::string s(buf.tailPtr(), buf.usedBytes());
     std::istringstream is(s);
@@ -397,8 +397,11 @@ bool parseHttpHeader(CirBuf &buf, std::string &websocket_key, int &websocket_ver
             websocket_key = value;
         else if (name == "sec-websocket-version")
             websocket_version = stoi(value);
-        else if (name == "sec-websocket-protocol" && value_lower == "mqtt")
+        else if (name == "sec-websocket-protocol" && strContains(value_lower, "mqtt"))
+        {
+            subprotocol = value;
             subprotocol_seen = true;
+        }
     }
 
     if (doubleEmptyLine)
@@ -489,14 +492,14 @@ std::string generateBadHttpRequestReponse(const std::string &msg)
     return oss.str();
 }
 
-std::string generateWebsocketAnswer(const std::string &acceptString)
+std::string generateWebsocketAnswer(const std::string &acceptString, const std::string &subprotocol)
 {
     std::ostringstream oss;
     oss << "HTTP/1.1 101 Switching Protocols\r\n";
     oss << "Upgrade: websocket\r\n";
     oss << "Connection: Upgrade\r\n";
     oss << "Sec-WebSocket-Accept: " << acceptString << "\r\n";
-    oss << "Sec-WebSocket-Protocol: mqtt\r\n";
+    oss << "Sec-WebSocket-Protocol: " << subprotocol << "\r\n";
     oss << "\r\n";
     oss.flush();
     return oss.str();
diff --git a/utils.h b/utils.h
index 8ab1152..0f2501e 100644
--- a/utils.h
+++ b/utils.h
@@ -77,7 +77,7 @@ std::string str_tolower(std::string s);
 bool stringTruthiness(const std::string &val);
 bool isPowerOfTwo(int val);
 
-bool parseHttpHeader(CirBuf &buf, std::string &websocket_key, int &websocket_version);
+bool parseHttpHeader(CirBuf &buf, std::string &websocket_key, int &websocket_version, std::string &subprotocol);
 
 std::vector<char> base64Decode(const std::string &s);
 std::string base64Encode(const unsigned char *input, const int length);
@@ -85,7 +85,7 @@ std::string generateWebsocketAcceptString(const std::string &websocketKey);
 
 std::string generateInvalidWebsocketVersionHttpHeaders(const int wantedVersion);
 std::string generateBadHttpRequestReponse(const std::string &msg);
-std::string generateWebsocketAnswer(const std::string &acceptString);
+std::string generateWebsocketAnswer(const std::string &acceptString, const std::string &subprotocol);
 
 void testSsl(const std::string &fullchain, const std::string &privkey);
 
--
libgit2 0.21.4