From 0ca073c7f4728aeb900e2e0a3d3942bdbe5bdb24 Mon Sep 17 00:00:00 2001
From: Sumeet Singh <sumeet.singh@espressif.com>
Date: Tue, 29 Oct 2024 19:23:36 +0530
Subject: [PATCH] feat(nimble): Added option to disable automatically sending
 extra credits to peer

---
 nimble/host/src/ble_l2cap_coc.c  |  4 ++--
 nimble/host/src/ble_l2cap_priv.h | 13 +++++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/nimble/host/src/ble_l2cap_coc.c b/nimble/host/src/ble_l2cap_coc.c
index f7b01a4af..2ae77a235 100644
--- a/nimble/host/src/ble_l2cap_coc.c
+++ b/nimble/host/src/ble_l2cap_coc.c
@@ -283,7 +283,7 @@ ble_l2cap_coc_rx_fn(struct ble_l2cap_chan *chan)
      * However, we still have buffer to for next LE Frame so lets give one more
      * credit to peer so it can send us full SDU
      */
-    if (rx->credits == 0) {
+    if (chan->disable_auto_credit_update == false && rx->credits == 0) {
         /* Remote did not send full SDU. Lets give him one more credits to do
          * so since we have still buffer to handle it
          */
@@ -598,7 +598,7 @@ ble_l2cap_coc_recv_ready(struct ble_l2cap_chan *chan, struct os_mbuf *sdu_rx)
     /* We want to back only that much credits which remote side is missing
      * to be able to send complete SDU.
      */
-    if (chan->coc_rx.credits < c->initial_credits) {
+    if (chan->disable_auto_credit_update == false && chan->coc_rx.credits < c->initial_credits) {
         ble_hs_unlock();
         ble_l2cap_sig_le_credits(chan->conn_handle, chan->scid,
                                  c->initial_credits - chan->coc_rx.credits);
diff --git a/nimble/host/src/ble_l2cap_priv.h b/nimble/host/src/ble_l2cap_priv.h
index 128afeed1..08ad3b3e8 100644
--- a/nimble/host/src/ble_l2cap_priv.h
+++ b/nimble/host/src/ble_l2cap_priv.h
@@ -92,6 +92,19 @@ struct ble_l2cap_chan {
     struct ble_l2cap_coc_endpoint coc_rx;
     struct ble_l2cap_coc_endpoint coc_tx;
     uint16_t initial_credits;
+/**
+ * Disable automatically sending credits to a remote
+ *
+ * This field disables automatically sending extra credit to a
+ * remote that has exhausted all of its available credits.
+ * Setting this field to "true" will enable behaviour to
+ * "not automatically send credits to a peer whose credits are exhausted"
+ * Setting this field to "false" will enable behaviour to
+ * "automatically send credits to a peer whose credits are exhausted"
+ * this behaviour.
+ *                      
+ */
+    bool disable_auto_credit_update;
     ble_l2cap_event_fn *cb;
     void *cb_arg;
 #endif