mqtt: improve the state machine

To handle PUBLISH before SUBACK and more.

Updated the existing tests and added three new ones.

Reported-by: Christoph Krey
Bug: https://curl.haxx.se/mail/lib-2020-04/0021.html
Closes #5246

9 files changed, 263 insertions, 34 deletions

diff --git a/tests/data/Makefile.inc b/tests/data/Makefile.inc
index 099940410..425a0c02f 100644
--- a/tests/data/Makefile.inc
+++ b/tests/data/Makefile.inc
@@ -139,7 +139,7 @@ test1160 test1161 test1162 test1163 test1164 test1165 test1166 test1167 \
 \
 test1170 test1171 test1172 test1173 test1174 test1175 test1176 test1177 \
 \
-test1190 test1191 test1192 test1193 \
+test1190 test1191 test1192 test1193 test1194 test1195 test1196 \
 \
 test1200 test1201 test1202 test1203 test1204 test1205 test1206 test1207 \
 test1208 test1209 test1210 test1211 test1212 test1213 test1214 test1215 \
diff --git a/tests/data/test1190 b/tests/data/test1190
index 491f2b843..007a15013 100644
--- a/tests/data/test1190
+++ b/tests/data/test1190
@@ -46,7 +46,7 @@ s/^(.* 00044d5154540402003c000c6375726c).*/$1/
 </strippart>
 <protocol>
 client CONNECT 18 00044d5154540402003c000c6375726c
-server CONACK 2 20020000
+server CONNACK 2 20020000
 client SUBSCRIBE 9 000100043131393000
 server SUBACK 3 9003000100
 server PUBLISH c 300c00043131393068656c6c6f0a
diff --git a/tests/data/test1191 b/tests/data/test1191
index fc8c68bb2..a36bc3113 100644
--- a/tests/data/test1191
+++ b/tests/data/test1191
@@ -42,7 +42,7 @@ s/^(.* 00044d5154540402003c000c6375726c).*/$1/
 </strippart>
 <protocol>
 client CONNECT 18 00044d5154540402003c000c6375726c
-server CONACK 2 20020000
+server CONNACK 2 20020000
 client PUBLISH f 000431313931736f6d657468696e67
 client DISCONNECT 0 e000
 </protocol>
diff --git a/tests/data/test1192 b/tests/data/test1192
index 92b96c3fd..691c7783f 100644
--- a/tests/data/test1192
+++ b/tests/data/test1192
@@ -46,7 +46,7 @@ s/^(.* 00044d5154540402003c000c6375726c).*/$1/
 </strippart>
 <protocol>
 client CONNECT 18 00044d5154540402003c000c6375726c
-server CONACK 2 20020000
+server CONNACK 2 20020000
 client SUBSCRIBE 80a 0001080541414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141412f3131393200
 server SUBACK 3 9003000100
 server PUBLISH 80d 308d10080541414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141414141412f3131393268656c6c6f0a
diff --git a/tests/data/test1193 b/tests/data/test1193
index 479ed5fe3..8da9abb21 100644
--- a/tests/data/test1193
+++ b/tests/data/test1193
@@ -64,7 +64,7 @@ s/^(.* 00044d5154540402003c000c6375726c).*/$1/
 </strippart>
 <protocol>
 client CONNECT 18 00044d5154540402003c000c6375726c
-server CONACK 2 20020000
+server CONNACK 2 20020000
 client PUBLISH 7c2 000431313933313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839303132333435363738393031323334353637383930313233343536373839
 client DISCONNECT 0 e000
 </protocol>
diff --git a/tests/data/test1194 b/tests/data/test1194
new file mode 100644
index 000000000..497891add
--- /dev/null
+++ b/tests/data/test1194
@@ -0,0 +1,59 @@
+<testcase>
+<info>
+<keywords>
+MQTT
+MQTT SUBSCRIBE
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<data nocheck="yes">
+hello
+</data>
+<datacheck hex="yes">
+00 04 31 31 39 30   68 65 6c 6c 6f 5b 4c 46 5d 0a
+</datacheck>
+<servercmd>
+PUBLISH-before-SUBACK TRUE
+</servercmd>
+</reply>
+
+#
+# Client-side
+<client>
+<features>
+mqtt
+</features>
+<server>
+mqtt
+</server>
+<name>
+MQTT SUBSCRIBE with PUBLISH befoire SUBACK
+</name>
+<command option="binary-trace">
+mqtt://%HOSTIP:%MQTTPORT/1194
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+# These are hexadecimal protocol dumps from the client
+#
+# Strip out the random part of the client id from the CONNECT message
+# before comparison
+<strippart>
+s/^(.* 00044d5154540402003c000c6375726c).*/$1/
+</strippart>
+<protocol>
+client CONNECT 18 00044d5154540402003c000c6375726c
+server CONNACK 2 20020000
+client SUBSCRIBE 9 000100043131393400
+server PUBLISH c 300c00043131393468656c6c6f0a
+server SUBACK 3 9003000100
+server DISCONNECT 0 e000
+</protocol>
+</verify>
+</testcase>
diff --git a/tests/data/test1195 b/tests/data/test1195
new file mode 100644
index 000000000..0dfaccd53
--- /dev/null
+++ b/tests/data/test1195
@@ -0,0 +1,63 @@
+<testcase>
+<info>
+<keywords>
+MQTT
+MQTT SUBSCRIBE
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<data nocheck="yes">
+hello
+</data>
+<datacheck hex="yes">
+00 04 31 31 39 30   68 65 6c 6c 6f 5b 4c 46 5d 0a
+</datacheck>
+<servercmd>
+PUBLISH-before-SUBACK TRUE
+short-PUBLISH TRUE
+</servercmd>
+</reply>
+
+#
+# Client-side
+<client>
+<features>
+mqtt
+</features>
+<server>
+mqtt
+</server>
+<name>
+MQTT SUBSCRIBE with short PUBLISH
+</name>
+<command option="binary-trace">
+mqtt://%HOSTIP:%MQTTPORT/1195
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+# These are hexadecimal protocol dumps from the client
+#
+# Strip out the random part of the client id from the CONNECT message
+# before comparison
+<strippart>
+s/^(.* 00044d5154540402003c000c6375726c).*/$1/
+</strippart>
+<protocol>
+client CONNECT 18 00044d5154540402003c000c6375726c
+server CONNACK 2 20020000
+client SUBSCRIBE 9 000100043131393500
+server PUBLISH c 300c00043131393568656c6c
+</protocol>
+
+# 18 is CURLE_PARTIAL_FILE
+<errorcode>
+18
+</errorcode>
+</verify>
+</testcase>
diff --git a/tests/data/test1196 b/tests/data/test1196
new file mode 100644
index 000000000..c07efd927
--- /dev/null
+++ b/tests/data/test1196
@@ -0,0 +1,62 @@
+<testcase>
+<info>
+<keywords>
+MQTT
+MQTT SUBSCRIBE
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<data nocheck="yes">
+hello
+</data>
+<datacheck hex="yes">
+00 04 31 31 39 30   68 65 6c 6c 6f 5b 4c 46 5d 0a
+</datacheck>
+
+# error 1 - "Connection Refused, unacceptable protocol version"
+<servercmd>
+error-CONNACK 1
+</servercmd>
+</reply>
+
+#
+# Client-side
+<client>
+<features>
+mqtt
+</features>
+<server>
+mqtt
+</server>
+<name>
+MQTT with error in CONNACK
+</name>
+<command option="binary-trace">
+mqtt://%HOSTIP:%MQTTPORT/1196
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+# These are hexadecimal protocol dumps from the client
+#
+# Strip out the random part of the client id from the CONNECT message
+# before comparison
+<strippart>
+s/^(.* 00044d5154540402003c000c6375726c).*/$1/
+</strippart>
+<protocol>
+client CONNECT 18 00044d5154540402003c000c6375726c
+server CONNACK 2 20020001
+</protocol>
+
+# 8 is CURLE_WEIRD_SERVER_REPLY
+<errorcode>
+8
+</errorcode>
+</verify>
+</testcase>
diff --git a/tests/server/mqttd.c b/tests/server/mqttd.c
index db5723cdd..6785b0014 100644
--- a/tests/server/mqttd.c
+++ b/tests/server/mqttd.c
@@ -104,6 +104,10 @@
 struct configurable {
   unsigned char version; /* initial version byte in the request must match
                             this */
+  bool publish_before_suback;
+  bool short_publish;
+  unsigned char error_connack;
+  int testnum;
 };
 
 #define REQUEST_DUMP  "log/server.input"
@@ -124,6 +128,10 @@ static void resetdefaults(void)
 {
   logmsg("Reset to defaults");
   config.version = CONFIG_VERSION;
+  config.publish_before_suback = FALSE;
+  config.short_publish = FALSE;
+  config.error_connack = 0;
+  config.testnum = 0;
 }
 
 static unsigned char byteval(char *value)
@@ -147,10 +155,29 @@ static void getconfig(void)
           config.version = byteval(value);
           logmsg("version [%d] set", config.version);
         }
+        else if(!strcmp(key, "PUBLISH-before-SUBACK")) {
+          logmsg("PUBLISH-before-SUBACK set");
+          config.publish_before_suback = TRUE;
+        }
+        else if(!strcmp(key, "short-PUBLISH")) {
+          logmsg("short-PUBLISH set");
+          config.short_publish = TRUE;
+        }
+        else if(!strcmp(key, "error-CONNACK")) {
+          config.error_connack = byteval(value);
+          logmsg("error-CONNACK = %d", config.error_connack);
+        }
+        else if(!strcmp(key, "Testnum")) {
+          config.testnum = atoi(value);
+          logmsg("testnum = %d", config.testnum);
+        }
       }
     }
     fclose(fp);
   }
+  else {
+    logmsg("No config file '%s' to read", configfile);
+  }
 }
 
 static void loghex(unsigned char *buffer, ssize_t len)
@@ -209,11 +236,17 @@ static int connack(FILE *dump, curl_socket_t fd)
     MQTT_MSG_CONNACK, 0x02,
     0x00, 0x00
   };
-  ssize_t rc = swrite(fd, (char *)packet, sizeof(packet));
-  if(rc == sizeof(packet)) {
-    logmsg("WROTE %d bytes [CONACK]", rc);
+  ssize_t rc;
+
+  packet[3] = config.error_connack;
+
+  rc = swrite(fd, (char *)packet, sizeof(packet));
+  if(rc > 0) {
+    logmsg("WROTE %d bytes [CONNACK]", rc);
     loghex(packet, rc);
-    logprotocol(FROM_SERVER, "CONACK", 2, dump, packet, sizeof(packet));
+    logprotocol(FROM_SERVER, "CONNACK", 2, dump, packet, sizeof(packet));
+  }
+  if(rc == sizeof(packet)) {
     return 0;
   }
   return 1;
@@ -360,6 +393,7 @@ static int publish(FILE *dump,
   size_t payloadindex;
   ssize_t remaininglength = topiclen + 2 + payloadlen;
   ssize_t packetlen;
+  ssize_t sendamount;
   ssize_t rc;
   char rembuffer[4];
   int encodedlen;
@@ -385,13 +419,18 @@ static int publish(FILE *dump,
   payloadindex = 3 + topiclen + encodedlen;
   memcpy(&packet[payloadindex], payload, payloadlen);
 
-  rc = swrite(fd, (char *)packet, packetlen);
-  if(rc == packetlen) {
+  sendamount = packetlen;
+  if(config.short_publish)
+    sendamount -= 2;
+
+  rc = swrite(fd, (char *)packet, sendamount);
+  if(rc > 0) {
     logmsg("WROTE %d bytes [PUBLISH]", rc);
     loghex(packet, rc);
     logprotocol(FROM_SERVER, "PUBLISH", remaininglength, dump, packet, rc);
-    return 0;
   }
+  if(rc == packetlen)
+    return 0;
   return 1;
 }
 
@@ -459,6 +498,11 @@ static curl_socket_t mqttit(curl_socket_t fd)
 
   getconfig();
 
+  testno = config.testnum;
+
+  if(testno)
+    logmsg("Found test number %ld", testno);
+
   do {
     /* get the fixed header */
     rc = fixedheader(fd, &byte, &remaining_length, &bytes);
@@ -506,8 +550,10 @@ static curl_socket_t mqttit(curl_socket_t fd)
       }
     }
     else if(byte == MQTT_MSG_SUBSCRIBE) {
-      char *testnop;
-
+      FILE *stream;
+      int error;
+      char *data;
+      size_t datalen;
       logprotocol(FROM_CLIENT, "SUBSCRIBE", remaining_length,
                   dump, buffer, rc);
       logmsg("Incoming SUBSCRIBE");
@@ -533,26 +579,25 @@ static curl_socket_t mqttit(curl_socket_t fd)
       /* there's a QoS byte (two bits) after the topic */
 
       logmsg("SUBSCRIBE to '%s' [%d]", topic, packet_id);
-      if(suback(dump, fd, packet_id)) {
-        logmsg("failed sending SUBACK");
-        goto end;
-      }
-      testnop = strrchr(topic, '/');
-      if(!testnop)
-        testnop = topic;
-      else
-        testnop++; /* pass the slash */
-      testno = strtol(testnop, NULL, 10);
-      if(testno) {
-        FILE *stream;
-        int error;
-        char *data;
-        size_t datalen;
-        logmsg("Found test number %ld", testno);
-        stream = test2fopen(testno);
-        error = getpart(&data, &datalen, "reply", "data", stream);
-        if(!error)
-          publish(dump, fd, packet_id, topic, data, datalen);
+      stream = test2fopen(testno);
+      error = getpart(&data, &datalen, "reply", "data", stream);
+      if(!error) {
+        if(!config.publish_before_suback) {
+          if(suback(dump, fd, packet_id)) {
+            logmsg("failed sending SUBACK");
+            goto end;
+          }
+        }
+        if(publish(dump, fd, packet_id, topic, data, datalen)) {
+          logmsg("PUBLISH failed");
+          goto end;
+        }
+        if(config.publish_before_suback) {
+          if(suback(dump, fd, packet_id)) {
+            logmsg("failed sending SUBACK");
+            goto end;
+          }
+        }
       }
       else {
         char *def = (char *)"this is random payload yes yes it is";