net: context: Add support for setting receive hop limit option

Add support for setting IPV6_RECVHOPLIMIT or IP_RECVTTL socket option.

Signed-off-by: Cristian Bulacu <[email protected]>

Author: Cristib05

include/zephyr/net/net_context.h

@@ -8,6 +8,7 @@
  * Copyright (c) 2016 Intel Corporation
  * Copyright (c) 2021 Nordic Semiconductor
  * Copyright (c) 2025 Aerlync Labs Inc.
+ * Copyright 2025 NXP
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -370,6 +371,10 @@ __net_socket struct net_context {
 		/** Receive network packet information in recvmsg() call */
 		bool recv_pktinfo;
 #endif
+#if defined(CONFIG_NET_CONTEXT_RECV_HOPLIMIT)
+		/** Receive IPv6 hop limit or IPv4 TTL as ancillary data in recvmsg() call */
+		bool recv_hoplimit;
+#endif
 #if defined(CONFIG_NET_IPV6)
 		/**
 		 * Source address selection preferences. Currently used only for IPv6,
@@ -1399,6 +1404,7 @@ enum net_context_option {
 	NET_OPT_LOCAL_PORT_RANGE  = 21, /**< Clamp local port range */
 	NET_OPT_IPV6_MCAST_LOOP	  = 22, /**< IPV6 multicast loop */
 	NET_OPT_IPV4_MCAST_LOOP	  = 23, /**< IPV4 multicast loop */
+	NET_OPT_RECV_HOPLIMIT     = 24, /**< Receive hop limit information */
 };
 
 /**

subsys/net/ip/Kconfig

@@ -3,6 +3,7 @@
 # Copyright (c) 2016 Intel Corporation.
 # Copyright (c) 2021 Nordic Semiconductor
 # Copyright (c) 2023 Arm Limited (or its affiliates). All rights reserved.
+# Copyright 2025 NXP
 # SPDX-License-Identifier: Apache-2.0
 
 menu "IP stack"
@@ -608,6 +609,14 @@ config NET_CONTEXT_RECV_PKTINFO
 	  This way user can get extra information about the received data in the
 	  socket.
 
+config NET_CONTEXT_RECV_HOPLIMIT
+	bool "Add receive hop limit (IPv6) or TTL (IPv4) support to net_context"
+	depends on NET_UDP
+	help
+	  Allow to set the IPV6_RECVHOPLIMIT or IP_RECVTTL flags on a socket.
+	  This way user can get extra information about hop limit (IPv6) or TTL (IPv4) in the
+	  socket.
+
 config NET_CONTEXT_TIMESTAMPING
 	bool "Add TIMESTAMPING support to net_context"
 	default y if (NET_UDP && NET_PKT_TIMESTAMP)

subsys/net/ip/net_context.c

@@ -8,6 +8,7 @@
  * Copyright (c) 2016 Intel Corporation
  * Copyright (c) 2021 Nordic Semiconductor
  * Copyright (c) 2025 Aerlync Labs Inc.
+ * Copyright 2025 NXP
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -130,6 +131,17 @@ bool net_context_is_recv_pktinfo_set(struct net_context *context)
 #endif
 }
 
+bool net_context_is_recv_hoplimit_set(struct net_context *context)
+{
+#if defined(CONFIG_NET_CONTEXT_RECV_HOPLIMIT)
+	return context->options.recv_hoplimit;
+#else
+	ARG_UNUSED(context);
+
+	return false;
+#endif
+}
+
 bool net_context_is_timestamping_set(struct net_context *context)
 {
 #if defined(CONFIG_NET_CONTEXT_TIMESTAMPING)
@@ -1919,6 +1931,21 @@ static int get_context_recv_pktinfo(struct net_context *context,
 #endif
 }
 
+static int get_context_recv_hoplimit(struct net_context *context,
+				    void *value, size_t *len)
+{
+#if defined(CONFIG_NET_CONTEXT_RECV_HOPLIMIT)
+	return get_bool_option(context->options.recv_hoplimit,
+			       value, len);
+#else
+	ARG_UNUSED(context);
+	ARG_UNUSED(value);
+	ARG_UNUSED(len);
+
+	return -ENOTSUP;
+#endif
+}
+
 static int get_context_addr_preferences(struct net_context *context,
 					void *value, size_t *len)
 {
@@ -3653,6 +3680,24 @@ static int set_context_recv_pktinfo(struct net_context *context,
 #endif
 }
 
+static int set_context_recv_hoplimit(struct net_context *context,
+				    const void *value, size_t len)
+{
+#if defined(CONFIG_NET_CONTEXT_RECV_HOPLIMIT)
+	if (net_context_get_type(context) == SOCK_DGRAM) {
+		return set_bool_option(&context->options.recv_hoplimit, value, len);
+	}
+
+	return -ENOTSUP;
+#else
+	ARG_UNUSED(context);
+	ARG_UNUSED(value);
+	ARG_UNUSED(len);
+
+	return -ENOTSUP;
+#endif
+}
+
 static int set_context_addr_preferences(struct net_context *context,
 					const void *value, size_t len)
 {
@@ -3877,6 +3922,9 @@ int net_context_set_option(struct net_context *context,
 	case NET_OPT_IPV4_MCAST_LOOP:
 		ret = set_context_ipv4_mcast_loop(context, value, len);
 		break;
+	case NET_OPT_RECV_HOPLIMIT:
+		ret = set_context_recv_hoplimit(context, value, len);
+		break;
 	}
 
 	k_mutex_unlock(&context->lock);
@@ -3968,6 +4016,9 @@ int net_context_get_option(struct net_context *context,
 	case NET_OPT_IPV4_MCAST_LOOP:
 		ret = get_context_ipv4_mcast_loop(context, value, len);
 		break;
+	case NET_OPT_RECV_HOPLIMIT:
+		ret = get_context_recv_hoplimit(context, value, len);
+		break;
 	}
 
 	k_mutex_unlock(&context->lock);

subsys/net/ip/net_private.h

@@ -96,6 +96,7 @@ extern bool net_context_is_reuseaddr_set(struct net_context *context);
 extern bool net_context_is_reuseport_set(struct net_context *context);
 extern bool net_context_is_v6only_set(struct net_context *context);
 extern bool net_context_is_recv_pktinfo_set(struct net_context *context);
+extern bool net_context_is_recv_hoplimit_set(struct net_context *context);
 extern bool net_context_is_timestamping_set(struct net_context *context);
 extern void net_pkt_init(void);
 int net_context_get_local_addr(struct net_context *context,
@@ -124,6 +125,11 @@ static inline bool net_context_is_recv_pktinfo_set(struct net_context *context)
 	ARG_UNUSED(context);
 	return false;
 }
+static inline bool net_context_is_recv_hoplimit_set(struct net_context *context)
+{
+	ARG_UNUSED(context);
+	return false;
+}
 static inline bool net_context_is_timestamping_set(struct net_context *context)
 {
 	ARG_UNUSED(context);