--- zzzz-none-000/linux-4.9.218/net/l2tp/l2tp_netlink.c	2020-04-02 15:20:41.000000000 +0000
+++ seale-7590ax-750/linux-4.9.218/net/l2tp/l2tp_netlink.c	2023-03-29 10:59:08.000000000 +0000
@@ -55,8 +55,7 @@
 /* Accessed under genl lock */
 static const struct l2tp_nl_cmd_ops *l2tp_nl_cmd_ops[__L2TP_PWTYPE_MAX];
 
-static struct l2tp_session *l2tp_nl_session_get(struct genl_info *info,
-						bool do_ref)
+static struct l2tp_session *l2tp_nl_session_get(struct genl_info *info)
 {
 	u32 tunnel_id;
 	u32 session_id;
@@ -67,15 +66,16 @@
 
 	if (info->attrs[L2TP_ATTR_IFNAME]) {
 		ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
-		session = l2tp_session_get_by_ifname(net, ifname, do_ref);
+		session = l2tp_session_get_by_ifname(net, ifname);
 	} else if ((info->attrs[L2TP_ATTR_SESSION_ID]) &&
 		   (info->attrs[L2TP_ATTR_CONN_ID])) {
 		tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
 		session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
-		tunnel = l2tp_tunnel_find(net, tunnel_id);
-		if (tunnel)
-			session = l2tp_session_get(net, tunnel, session_id,
-						   do_ref);
+		tunnel = l2tp_tunnel_get(net, tunnel_id);
+		if (tunnel) {
+			session = l2tp_session_get(net, tunnel, session_id);
+			l2tp_tunnel_dec_refcount(tunnel);
+		}
 	}
 
 	return session;
@@ -278,8 +278,8 @@
 	}
 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
 
-	tunnel = l2tp_tunnel_find(net, tunnel_id);
-	if (tunnel == NULL) {
+	tunnel = l2tp_tunnel_get(net, tunnel_id);
+	if (!tunnel) {
 		ret = -ENODEV;
 		goto out;
 	}
@@ -289,6 +289,8 @@
 
 	l2tp_tunnel_delete(tunnel);
 
+	l2tp_tunnel_dec_refcount(tunnel);
+
 out:
 	return ret;
 }
@@ -306,8 +308,8 @@
 	}
 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
 
-	tunnel = l2tp_tunnel_find(net, tunnel_id);
-	if (tunnel == NULL) {
+	tunnel = l2tp_tunnel_get(net, tunnel_id);
+	if (!tunnel) {
 		ret = -ENODEV;
 		goto out;
 	}
@@ -318,6 +320,8 @@
 	ret = l2tp_tunnel_notify(&l2tp_nl_family, info,
 				 tunnel, L2TP_CMD_TUNNEL_MODIFY);
 
+	l2tp_tunnel_dec_refcount(tunnel);
+
 out:
 	return ret;
 }
@@ -430,34 +434,37 @@
 
 	if (!info->attrs[L2TP_ATTR_CONN_ID]) {
 		ret = -EINVAL;
-		goto out;
+		goto err;
 	}
 
 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
 
-	tunnel = l2tp_tunnel_find(net, tunnel_id);
-	if (tunnel == NULL) {
-		ret = -ENODEV;
-		goto out;
-	}
-
 	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 	if (!msg) {
 		ret = -ENOMEM;
-		goto out;
+		goto err;
+	}
+
+	tunnel = l2tp_tunnel_get(net, tunnel_id);
+	if (!tunnel) {
+		ret = -ENODEV;
+		goto err_nlmsg;
 	}
 
 	ret = l2tp_nl_tunnel_send(msg, info->snd_portid, info->snd_seq,
 				  NLM_F_ACK, tunnel, L2TP_CMD_TUNNEL_GET);
 	if (ret < 0)
-		goto err_out;
+		goto err_nlmsg_tunnel;
+
+	l2tp_tunnel_dec_refcount(tunnel);
 
 	return genlmsg_unicast(net, msg, info->snd_portid);
 
-err_out:
+err_nlmsg_tunnel:
+	l2tp_tunnel_dec_refcount(tunnel);
+err_nlmsg:
 	nlmsg_free(msg);
-
-out:
+err:
 	return ret;
 }
 
@@ -501,8 +508,9 @@
 		ret = -EINVAL;
 		goto out;
 	}
+
 	tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
-	tunnel = l2tp_tunnel_find(net, tunnel_id);
+	tunnel = l2tp_tunnel_get(net, tunnel_id);
 	if (!tunnel) {
 		ret = -ENODEV;
 		goto out;
@@ -510,32 +518,30 @@
 
 	if (!info->attrs[L2TP_ATTR_SESSION_ID]) {
 		ret = -EINVAL;
-		goto out;
+		goto out_tunnel;
 	}
 	session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
-	session = l2tp_session_find(net, tunnel, session_id);
-	if (session) {
-		ret = -EEXIST;
-		goto out;
-	}
 
 	if (!info->attrs[L2TP_ATTR_PEER_SESSION_ID]) {
 		ret = -EINVAL;
-		goto out;
+		goto out_tunnel;
 	}
 	peer_session_id = nla_get_u32(info->attrs[L2TP_ATTR_PEER_SESSION_ID]);
 
 	if (!info->attrs[L2TP_ATTR_PW_TYPE]) {
 		ret = -EINVAL;
-		goto out;
+		goto out_tunnel;
 	}
 	cfg.pw_type = nla_get_u16(info->attrs[L2TP_ATTR_PW_TYPE]);
 	if (cfg.pw_type >= __L2TP_PWTYPE_MAX) {
 		ret = -EINVAL;
-		goto out;
+		goto out_tunnel;
 	}
 
 	if (tunnel->version > 2) {
+		if (info->attrs[L2TP_ATTR_OFFSET])
+			cfg.offset = nla_get_u16(info->attrs[L2TP_ATTR_OFFSET]);
+
 		if (info->attrs[L2TP_ATTR_DATA_SEQ])
 			cfg.data_seq = nla_get_u8(info->attrs[L2TP_ATTR_DATA_SEQ]);
 
@@ -551,7 +557,7 @@
 			u16 len = nla_len(info->attrs[L2TP_ATTR_COOKIE]);
 			if (len > 8) {
 				ret = -EINVAL;
-				goto out;
+				goto out_tunnel;
 			}
 			cfg.cookie_len = len;
 			memcpy(&cfg.cookie[0], nla_data(info->attrs[L2TP_ATTR_COOKIE]), len);
@@ -560,7 +566,7 @@
 			u16 len = nla_len(info->attrs[L2TP_ATTR_PEER_COOKIE]);
 			if (len > 8) {
 				ret = -EINVAL;
-				goto out;
+				goto out_tunnel;
 			}
 			cfg.peer_cookie_len = len;
 			memcpy(&cfg.peer_cookie[0], nla_data(info->attrs[L2TP_ATTR_PEER_COOKIE]), len);
@@ -603,7 +609,7 @@
 	if ((l2tp_nl_cmd_ops[cfg.pw_type] == NULL) ||
 	    (l2tp_nl_cmd_ops[cfg.pw_type]->session_create == NULL)) {
 		ret = -EPROTONOSUPPORT;
-		goto out;
+		goto out_tunnel;
 	}
 
 	/* Check that pseudowire-specific params are present */
@@ -613,7 +619,7 @@
 	case L2TP_PWTYPE_ETH_VLAN:
 		if (!info->attrs[L2TP_ATTR_VLAN_ID]) {
 			ret = -EINVAL;
-			goto out;
+			goto out_tunnel;
 		}
 		break;
 	case L2TP_PWTYPE_ETH:
@@ -627,13 +633,13 @@
 		break;
 	}
 
-	ret = -EPROTONOSUPPORT;
-	if (l2tp_nl_cmd_ops[cfg.pw_type]->session_create)
-		ret = (*l2tp_nl_cmd_ops[cfg.pw_type]->session_create)(net, tunnel_id,
-			session_id, peer_session_id, &cfg);
+	ret = l2tp_nl_cmd_ops[cfg.pw_type]->session_create(net, tunnel,
+							   session_id,
+							   peer_session_id,
+							   &cfg);
 
 	if (ret >= 0) {
-		session = l2tp_session_get(net, tunnel, session_id, false);
+		session = l2tp_session_get(net, tunnel, session_id);
 		if (session) {
 			ret = l2tp_session_notify(&l2tp_nl_family, info, session,
 						  L2TP_CMD_SESSION_CREATE);
@@ -641,6 +647,8 @@
 		}
 	}
 
+out_tunnel:
+	l2tp_tunnel_dec_refcount(tunnel);
 out:
 	return ret;
 }
@@ -651,7 +659,7 @@
 	struct l2tp_session *session;
 	u16 pw_type;
 
-	session = l2tp_nl_session_get(info, true);
+	session = l2tp_nl_session_get(info);
 	if (session == NULL) {
 		ret = -ENODEV;
 		goto out;
@@ -665,8 +673,6 @@
 		if (l2tp_nl_cmd_ops[pw_type] && l2tp_nl_cmd_ops[pw_type]->session_delete)
 			ret = (*l2tp_nl_cmd_ops[pw_type]->session_delete)(session);
 
-	if (session->deref)
-		session->deref(session);
 	l2tp_session_dec_refcount(session);
 
 out:
@@ -678,7 +684,7 @@
 	int ret = 0;
 	struct l2tp_session *session;
 
-	session = l2tp_nl_session_get(info, false);
+	session = l2tp_nl_session_get(info);
 	if (session == NULL) {
 		ret = -ENODEV;
 		goto out;
@@ -810,7 +816,7 @@
 	struct sk_buff *msg;
 	int ret;
 
-	session = l2tp_nl_session_get(info, false);
+	session = l2tp_nl_session_get(info);
 	if (session == NULL) {
 		ret = -ENODEV;
 		goto err;
@@ -856,7 +862,7 @@
 				goto out;
 		}
 
-		session = l2tp_session_get_nth(tunnel, si, false);
+		session = l2tp_session_get_nth(tunnel, si);
 		if (session == NULL) {
 			ti++;
 			tunnel = NULL;