net: Add support for adjusting IPv6 unicast hop limit

Add option support for adjusting the IPv6 unicast
hop limit value.

Signed-off-by: Jukka Rissanen <[email protected]>

Author: jukkar

include/zephyr/net/net_context.h

@@ -1122,20 +1122,21 @@ int net_context_update_recv_wnd(struct net_context *context,
 				int32_t delta);
 
 enum net_context_option {
-	NET_OPT_PRIORITY	= 1,
-	NET_OPT_TXTIME		= 2,
-	NET_OPT_SOCKS5		= 3,
-	NET_OPT_RCVTIMEO        = 4,
-	NET_OPT_SNDTIMEO        = 5,
-	NET_OPT_RCVBUF		= 6,
-	NET_OPT_SNDBUF		= 7,
-	NET_OPT_DSCP_ECN	= 8,
-	NET_OPT_REUSEADDR	= 9,
-	NET_OPT_REUSEPORT	= 10,
-	NET_OPT_IPV6_V6ONLY	= 11,
-	NET_OPT_RECV_PKTINFO    = 12,
-	NET_OPT_MCAST_TTL	= 13,
-	NET_OPT_MCAST_HOP_LIMIT = 14,
+	NET_OPT_PRIORITY          = 1,
+	NET_OPT_TXTIME            = 2,
+	NET_OPT_SOCKS5            = 3,
+	NET_OPT_RCVTIMEO          = 4,
+	NET_OPT_SNDTIMEO          = 5,
+	NET_OPT_RCVBUF            = 6,
+	NET_OPT_SNDBUF            = 7,
+	NET_OPT_DSCP_ECN          = 8,
+	NET_OPT_REUSEADDR         = 9,
+	NET_OPT_REUSEPORT         = 10,
+	NET_OPT_IPV6_V6ONLY       = 11,
+	NET_OPT_RECV_PKTINFO      = 12,
+	NET_OPT_MCAST_TTL         = 13,
+	NET_OPT_MCAST_HOP_LIMIT   = 14,
+	NET_OPT_UNICAST_HOP_LIMIT = 15,
 };
 
 /**

include/zephyr/net/socket.h

@@ -1116,6 +1116,9 @@ struct in_pktinfo {
 #define IP_MULTICAST_TTL 33
 
 /* Socket options for IPPROTO_IPV6 level */
+/** sockopt: Set the unicast hop limit for the socket. */
+#define IPV6_UNICAST_HOPS	16
+
 /** sockopt: Set the multicast hop limit for the socket. */
 #define IPV6_MULTICAST_HOPS 18
 

subsys/net/ip/net_context.c

@@ -54,6 +54,12 @@ LOG_MODULE_REGISTER(net_ctx, CONFIG_NET_CONTEXT_LOG_LEVEL);
 #define INITIAL_MCAST_HOP_LIMIT 1
 #endif
 
+#ifdef CONFIG_NET_INITIAL_HOP_LIMIT
+#define INITIAL_HOP_LIMIT CONFIG_NET_INITIAL_HOP_LIMIT
+#else
+#define INITIAL_HOP_LIMIT 1
+#endif
+
 #ifndef EPFNOSUPPORT
 /* Some old versions of newlib haven't got this defined in errno.h,
  * Just use EPROTONOSUPPORT in this case
@@ -481,6 +487,7 @@ int net_context_get(sa_family_t family, enum net_sock_type type, uint16_t proto,
 					break;
 				}
 
+				contexts[i].ipv6_hop_limit = INITIAL_HOP_LIMIT;
 				contexts[i].ipv6_mcast_hop_limit = INITIAL_MCAST_HOP_LIMIT;
 			}
 			if (IS_ENABLED(CONFIG_NET_IPV4) && family == AF_INET) {
@@ -1124,8 +1131,6 @@ int net_context_create_ipv6_new(struct net_context *context,
 						  (struct in6_addr *)dst);
 	}
 
-	net_pkt_set_ipv6_hop_limit(pkt,
-				   net_context_get_ipv6_hop_limit(context));
 #if defined(CONFIG_NET_CONTEXT_DSCP_ECN)
 	net_pkt_set_ip_dscp(pkt, net_ipv6_get_dscp(context->options.dscp_ecn));
 	net_pkt_set_ip_ecn(pkt, net_ipv6_get_ecn(context->options.dscp_ecn));
@@ -1600,6 +1605,26 @@ static int get_context_mcast_hop_limit(struct net_context *context,
 #endif
 }
 
+static int get_context_unicast_hop_limit(struct net_context *context,
+					 void *value, size_t *len)
+{
+#if defined(CONFIG_NET_IPV6)
+	*((int *)value) = context->ipv6_hop_limit;
+
+	if (len) {
+		*len = sizeof(int);
+	}
+
+	return 0;
+#else
+	ARG_UNUSED(context);
+	ARG_UNUSED(value);
+	ARG_UNUSED(len);
+
+	return -ENOTSUP;
+#endif
+}
+
 static int get_context_reuseaddr(struct net_context *context,
 				 void *value, size_t *len)
 {
@@ -2822,6 +2847,25 @@ static int set_context_mcast_hop_limit(struct net_context *context,
 #endif
 }
 
+static int set_context_unicast_hop_limit(struct net_context *context,
+					 const void *value, size_t len)
+{
+#if defined(CONFIG_NET_IPV6)
+	uint8_t unicast_hop_limit = *((int *)value);
+
+	len = sizeof(context->ipv6_hop_limit);
+
+	return set_uint8_option(&context->ipv6_hop_limit,
+				&unicast_hop_limit, len);
+#else
+	ARG_UNUSED(context);
+	ARG_UNUSED(value);
+	ARG_UNUSED(len);
+
+	return -ENOTSUP;
+#endif
+}
+
 static int set_context_reuseaddr(struct net_context *context,
 				 const void *value, size_t len)
 {
@@ -2923,6 +2967,9 @@ int net_context_set_option(struct net_context *context,
 	case NET_OPT_MCAST_HOP_LIMIT:
 		ret = set_context_mcast_hop_limit(context, value, len);
 		break;
+	case NET_OPT_UNICAST_HOP_LIMIT:
+		ret = set_context_unicast_hop_limit(context, value, len);
+		break;
 	case NET_OPT_REUSEADDR:
 		ret = set_context_reuseaddr(context, value, len);
 		break;
@@ -2987,6 +3034,9 @@ int net_context_get_option(struct net_context *context,
 	case NET_OPT_MCAST_HOP_LIMIT:
 		ret = get_context_mcast_hop_limit(context, value, len);
 		break;
+	case NET_OPT_UNICAST_HOP_LIMIT:
+		ret = get_context_unicast_hop_limit(context, value, len);
+		break;
 	case NET_OPT_REUSEADDR:
 		ret = get_context_reuseaddr(context, value, len);
 		break;

subsys/net/lib/sockets/sockets.c

@@ -2565,6 +2565,17 @@ int zsock_getsockopt_ctx(struct net_context *ctx, int level, int optname,
 
 			break;
 
+		case IPV6_UNICAST_HOPS:
+			ret = net_context_get_option(ctx,
+						     NET_OPT_UNICAST_HOP_LIMIT,
+						     optval, optlen);
+			if (ret < 0) {
+				errno  = -ret;
+				return -1;
+			}
+
+			return 0;
+
 		case IPV6_MULTICAST_HOPS:
 			ret = net_context_get_option(ctx,
 						     NET_OPT_MCAST_HOP_LIMIT,
@@ -2969,6 +2980,17 @@ int zsock_setsockopt_ctx(struct net_context *ctx, int level, int optname,
 
 			break;
 
+		case IPV6_UNICAST_HOPS:
+			ret = net_context_set_option(ctx,
+						     NET_OPT_UNICAST_HOP_LIMIT,
+						     optval, optlen);
+			if (ret < 0) {
+				errno  = -ret;
+				return -1;
+			}
+
+			return 0;
+
 		case IPV6_MULTICAST_HOPS:
 			ret = net_context_set_option(ctx,
 						     NET_OPT_MCAST_HOP_LIMIT,