From 8f63a8f3bffbbaf8fae4985ee5f974ab326b08c0 Mon Sep 17 00:00:00 2001
From: Philippe Antoine <pantoine@oisf.net>
Date: Fri, 7 Apr 2023 16:02:41 +0200
Subject: [PATCH] http1: remove transactions from their list

instead of keeping a NULL pointer in an array

Ticket: #5921
---
 src/app-layer-htp-file.c |  3 ++-
 src/app-layer-htp.c      | 16 +++++++++-------
 src/app-layer-htp.h      |  7 +++++++
 3 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/src/app-layer-htp-file.c b/src/app-layer-htp-file.c
index f96b370160..7b3ba62edc 100644
--- a/src/app-layer-htp-file.c
+++ b/src/app-layer-htp-file.c
@@ -179,7 +179,8 @@ int HTPFileOpenWithRange(HtpState *s, HtpTxUserData *txud, const uint8_t *filena
     }
 
     // Then, we will try to handle reassembly of different ranges of the same file
-    htp_tx_t *tx = htp_list_get(s->conn->transactions, txid);
+    // TODO have the caller pass directly the tx
+    htp_tx_t *tx = htp_list_get(s->conn->transactions, txid - s->tx_freed);
     if (!tx) {
         SCReturnInt(-1);
     }
diff --git a/src/app-layer-htp.c b/src/app-layer-htp.c
index 1e8c0b8ea6..babb87d283 100644
--- a/src/app-layer-htp.c
+++ b/src/app-layer-htp.c
@@ -401,7 +401,7 @@ void HTPStateFree(void *state)
         uint64_t total_txs = HTPStateGetTxCnt(state);
         /* free the list of body chunks */
         if (s->conn != NULL) {
-            for (tx_id = 0; tx_id < total_txs; tx_id++) {
+            for (tx_id = s->tx_freed; tx_id < total_txs; tx_id++) {
                 htp_tx_t *tx = HTPStateGetTx(s, tx_id);
                 if (tx != NULL) {
                     HtpTxUserData *htud = (HtpTxUserData *) htp_tx_get_user_data(tx);
@@ -458,8 +458,10 @@ static void HTPStateTransactionFree(void *state, uint64_t id)
             tx->request_progress = HTP_REQUEST_COMPLETE;
             tx->response_progress = HTP_RESPONSE_COMPLETE;
         }
+        // replaces tx in the s->conn->transactions list by NULL
         htp_tx_destroy(tx);
     }
+    s->tx_freed += htp_connp_tx_freed(s->connp);
 }
 
 /**
@@ -3076,7 +3078,7 @@ static uint64_t HTPStateGetTxCnt(void *alstate)
         if (size < 0)
             return 0ULL;
         SCLogDebug("size %"PRIu64, size);
-        return (uint64_t)size;
+        return (uint64_t)size + http_state->tx_freed;
     } else {
         return 0ULL;
     }
@@ -3086,8 +3088,8 @@ static void *HTPStateGetTx(void *alstate, uint64_t tx_id)
 {
     HtpState *http_state = (HtpState *)alstate;
 
-    if (http_state != NULL && http_state->conn != NULL)
-        return htp_list_get(http_state->conn->transactions, tx_id);
+    if (http_state != NULL && http_state->conn != NULL && tx_id >= http_state->tx_freed)
+        return htp_list_get(http_state->conn->transactions, tx_id - http_state->tx_freed);
     else
         return NULL;
 }
@@ -3097,9 +3099,9 @@ void *HtpGetTxForH2(void *alstate)
     // gets last transaction
     HtpState *http_state = (HtpState *)alstate;
     if (http_state != NULL && http_state->conn != NULL) {
-        size_t txid = htp_list_array_size(http_state->conn->transactions);
-        if (txid > 0) {
-            return htp_list_get(http_state->conn->transactions, txid - 1);
+        size_t txid = HTPStateGetTxCnt(http_state);
+        if (txid > http_state->tx_freed) {
+            return htp_list_get(http_state->conn->transactions, txid - http_state->tx_freed - 1);
         }
     }
     return NULL;
diff --git a/src/app-layer-htp.h b/src/app-layer-htp.h
index dee5c17e83..5972bdaf50 100644
--- a/src/app-layer-htp.h
+++ b/src/app-layer-htp.h
@@ -247,6 +247,13 @@ typedef struct HtpState_ {
     htp_conn_t *conn;
     Flow *f;                /**< Needed to retrieve the original flow when using HTPLib callbacks */
     uint64_t transaction_cnt;
+    // tx_freed is the number of already freed transactions
+    // This is needed as libhtp only keeps the live transactions :
+    // To get the total number of transactions, we need to add
+    // the number of transactions tracked by libhtp to this number.
+    // It is also needed as an offset to translate between suricata
+    // transaction id to libhtp offset in its list/array
+    uint64_t tx_freed;
     const struct HTPCfgRec_ *cfg;
     uint16_t flags;
     uint16_t events;