From 05f3aab743f097d1f8f10de77201e579e29d110a Mon Sep 17 00:00:00 2001
From: Pauli Virtanen <pav@iki.fi>
Date: Mon, 6 Oct 2025 01:17:39 +0300
Subject: [PATCH] bthost: handle L2CAP_DISCONN_RSP and remove l2cap_conns

Handle L2CAP disconnection response. On receiving disconnection request
or response, remove the associated connection.

Change disconnect handler signature to take also the handle and CID.
---
 emulator/bthost.c    | 61 +++++++++++++++++++++++++++++++++++++++++++-
 emulator/bthost.h    |  6 ++++-
 tools/l2cap-tester.c |  3 ++-
 3 files changed, 67 insertions(+), 3 deletions(-)

diff --git a/emulator/bthost.c b/emulator/bthost.c
index c85f751cc..93023331e 100644
--- a/emulator/bthost.c
+++ b/emulator/bthost.c
@@ -403,6 +403,25 @@ static struct l2conn *bthost_add_l2cap_conn(struct bthost *bthost,
 	return l2conn;
 }
 
+static void btconn_detach_l2cap_conn(struct btconn *conn, struct l2conn *l2conn)
+{
+	struct l2conn *c;
+
+	if (conn->l2conns == l2conn) {
+		conn->l2conns = l2conn->next;
+		l2conn->next = NULL;
+		return;
+	}
+
+	for (c = conn->l2conns; c != NULL; c = c->next) {
+		if (c->next == l2conn) {
+			c->next = l2conn->next;
+			l2conn->next = NULL;
+			return;
+		}
+	}
+}
+
 static struct rcconn *bthost_add_rfcomm_conn(struct bthost *bthost,
 						struct btconn *conn,
 						struct l2conn *l2conn,
@@ -2142,11 +2161,41 @@ static bool l2cap_disconn_req(struct bthost *bthost, struct btconn *conn,
 	if (!l2conn)
 		return true;
 
+	btconn_detach_l2cap_conn(conn, l2conn);
+
 	cb_data = bthost_find_l2cap_cb_by_psm(bthost, l2conn->psm);
 
 	if (cb_data && cb_data->disconn_func)
-		cb_data->disconn_func(cb_data->user_data);
+		cb_data->disconn_func(conn->handle, l2conn->dcid,
+							cb_data->user_data);
 
+	l2conn_free(l2conn);
+	return true;
+}
+
+static bool l2cap_disconn_rsp(struct bthost *bthost, struct btconn *conn,
+				uint8_t ident, const void *data, uint16_t len)
+{
+	const struct bt_l2cap_pdu_disconn_rsp *rsp = data;
+	struct l2cap_conn_cb_data *cb_data;
+	struct l2conn *l2conn;
+
+	if (len < sizeof(*rsp))
+		return false;
+
+	l2conn = btconn_find_l2cap_conn_by_scid(conn, rsp->dcid);
+	if (!l2conn)
+		return true;
+
+	btconn_detach_l2cap_conn(conn, l2conn);
+
+	cb_data = bthost_find_l2cap_cb_by_psm(bthost, l2conn->psm);
+
+	if (cb_data && cb_data->disconn_func)
+		cb_data->disconn_func(conn->handle, l2conn->dcid,
+							cb_data->user_data);
+
+	l2conn_free(l2conn);
 	return true;
 }
 
@@ -2302,6 +2351,11 @@ static void l2cap_sig(struct bthost *bthost, struct btconn *conn,
 						data + sizeof(*hdr), hdr_len);
 		break;
 
+	case BT_L2CAP_PDU_DISCONN_RSP:
+		ret = l2cap_disconn_rsp(bthost, conn, hdr->ident,
+						data + sizeof(*hdr), hdr_len);
+		break;
+
 	case BT_L2CAP_PDU_INFO_REQ:
 		ret = l2cap_info_req(bthost, conn, hdr->ident,
 						data + sizeof(*hdr), hdr_len);
@@ -2536,6 +2590,11 @@ static void l2cap_le_sig(struct bthost *bthost, struct btconn *conn,
 						data + sizeof(*hdr), hdr_len);
 		break;
 
+	case BT_L2CAP_PDU_DISCONN_RSP:
+		ret = l2cap_disconn_rsp(bthost, conn, hdr->ident,
+						data + sizeof(*hdr), hdr_len);
+		break;
+
 	case BT_L2CAP_PDU_CONN_PARAM_REQ:
 		ret = l2cap_conn_param_req(bthost, conn, hdr->ident,
 						data + sizeof(*hdr), hdr_len);
diff --git a/emulator/bthost.h b/emulator/bthost.h
index 743615838..d60111d25 100644
--- a/emulator/bthost.h
+++ b/emulator/bthost.h
@@ -99,6 +99,9 @@ void bthost_send_iso(struct bthost *bthost, uint16_t handle, bool ts,
 			uint16_t sn, uint32_t timestamp, uint8_t pkt_status,
 			const struct iovec *iov, int iovcnt);
 
+void bthost_disconnect_cid(struct bthost *bthost, uint16_t handle,
+								uint16_t cid);
+
 typedef void (*bthost_l2cap_rsp_cb) (uint8_t code, const void *data,
 						uint16_t len, void *user_data);
 
@@ -145,7 +148,8 @@ void bthost_le_start_encrypt(struct bthost *bthost, uint16_t handle,
 							const uint8_t ltk[16]);
 typedef void (*bthost_l2cap_connect_cb) (uint16_t handle, uint16_t cid,
 							void *user_data);
-typedef void (*bthost_l2cap_disconnect_cb) (void *user_data);
+typedef void (*bthost_l2cap_disconnect_cb) (uint16_t handle, uint16_t cid,
+							void *user_data);
 
 void bthost_add_l2cap_server(struct bthost *bthost, uint16_t psm,
 				bthost_l2cap_connect_cb func,
diff --git a/tools/l2cap-tester.c b/tools/l2cap-tester.c
index 208772527..a9ab8b051 100644
--- a/tools/l2cap-tester.c
+++ b/tools/l2cap-tester.c
@@ -1726,7 +1726,8 @@ static void client_l2cap_connect_cb(uint16_t handle, uint16_t cid,
 	data->handle = handle;
 }
 
-static void client_l2cap_disconnect_cb(void *user_data)
+static void client_l2cap_disconnect_cb(uint16_t handle, uint16_t cid,
+							void *user_data)
 {
 	struct test_data *data = user_data;
 
-- 
2.47.3