pgsql: debug validation on duplicated request msgs

There shouldn't be duplicated messages in the requests Vec. And thus
the parser shouldn't log duplicated keys nor messages. Add debug
validations to ensure this.

With PGSQL's current state machine, most frontend/ client messages will
lead to the creation of a new transaction - which would prevent
duplicated messages being pushed to the requests array and reaching the
logger.

The current exceptions for that are:

- CopyDataIn
- CopyDone
- CopyFail

Thus, debug statements were added for those cases.

CopyDone and CopyFail, per the documentation, shouldn't be seen
duplicated on the wire for the same transaction. CopyDataIn -- yes, but
we consolidate those, so the expectation is that they won't be
duplicated in the requests array or when reaching the logger either.

Related to
Task #7645

rust/src/pgsql/logger.rs

@@ -31,12 +31,10 @@ fn log_pgsql(tx: &PgsqlTransaction, flags: u32, js: &mut JsonBuilder) -> Result<
     js.set_uint("tx_id", tx.tx_id)?;
     if !tx.requests.is_empty() {
         // For now, even if 'requests' is an array, we don't need to log it as such, as
-        // there are no duplicated messages
+        // there should be no duplicated messages, and there should be no more than 2 requests per tx
+        debug_validate_bug_on!(tx.requests.len() > 2);
         js.open_object("request")?;
-        for request in &tx.requests {
-            SCLogNotice!("Suricata requests length: {}", tx.requests.len());
-            log_request(request, flags, js)?;
-        }
+        log_request(tx, flags, js)?;
         js.close()?;
     } else if tx.responses.is_empty() {
         SCLogDebug!("Suricata created an empty PGSQL transaction");
@@ -55,7 +53,11 @@ fn log_pgsql(tx: &PgsqlTransaction, flags: u32, js: &mut JsonBuilder) -> Result<
     Ok(())
 }
 
-fn log_request(req: &PgsqlFEMessage, flags: u32, js: &mut JsonBuilder) -> Result<(), JsonError> {
+fn log_request(tx: &PgsqlTransaction, flags: u32, js: &mut JsonBuilder) -> Result<(), JsonError> {
+    // CopyFail, ConsolidatedCopyDataIn, CopyDone
+    let mut duplicated_messages: [u8; 3] = [0, 0, 0];
+    for req in &tx.requests {
+        SCLogDebug!("Suricata requests length: {}", tx.requests.len());
         match req {
             PgsqlFEMessage::StartupMessage(StartupPacket {
                 length: _,
@@ -102,13 +104,17 @@ fn log_request(req: &PgsqlFEMessage, flags: u32, js: &mut JsonBuilder) -> Result
                 identifier: _,
                 length: _,
                 payload,
-        })
-        | PgsqlFEMessage::CopyFail(RegularPacket {
+            }) => {
+                js.set_string_from_bytes(req.to_str(), payload)?;
+            }
+            PgsqlFEMessage::CopyFail(RegularPacket {
                 identifier: _,
                 length: _,
                 payload,
             }) => {
                 js.set_string_from_bytes(req.to_str(), payload)?;
+                duplicated_messages[0] += 1;
+                debug_validate_bug_on!(duplicated_messages[0] > 1);
             }
             PgsqlFEMessage::CancelRequest(CancelRequestMessage { pid, backend_key }) => {
                 js.set_string("message", "cancel_request")?;
@@ -124,9 +130,15 @@ fn log_request(req: &PgsqlFEMessage, flags: u32, js: &mut JsonBuilder) -> Result
                 js.set_uint("msg_count", *row_cnt)?;
                 js.set_uint("data_size", *data_size)?;
                 js.close()?;
+                duplicated_messages[1] += 1;
+                debug_validate_bug_on!(duplicated_messages[1] > 1);
+            }
+            PgsqlFEMessage::CopyDone(_) => {
+                js.set_string("message", req.to_str())?;
+                duplicated_messages[2] += 1;
+                debug_validate_bug_on!(duplicated_messages[2] > 1);
             }
-        PgsqlFEMessage::CopyDone(_)
-        | PgsqlFEMessage::Terminate(_) => {
+            PgsqlFEMessage::Terminate(_) => {
                 js.set_string("message", req.to_str())?;
             }
             PgsqlFEMessage::UnknownMessageType(RegularPacket {
@@ -137,6 +149,7 @@ fn log_request(req: &PgsqlFEMessage, flags: u32, js: &mut JsonBuilder) -> Result
                 // We don't want to log these, for now. Cf redmine: #6576
             }
         }
+    }
     Ok(())
 }