net: shell: udp: allow sending packet when bound

"udp bind" and "udp send" commands use the same net context
variable and they fail early if the context is already used.

This prevents from using "udp send" after "udp bind", which
makes the commands hard to use for testing bidirectional
communication. Make "udp send" reuse the already bound
context if possible, and resort to allocating temporary one
otherwise.

Signed-off-by: Damian Krolik <damian.krolik@nordicsemi.no>

Author: Damian-Nordic

subsys/net/lib/shell/udp.c

@@ -82,7 +82,7 @@ static int cmd_net_udp_bind(const struct shell *sh, size_t argc, char *argv[])
 		return -EINVAL;
 	}
 
-	if (udp_ctx && net_context_is_used(udp_ctx)) {
+	if (udp_ctx != NULL && net_context_is_used(udp_ctx)) {
 		PR_WARNING("Network context already in use\n");
 		return -EALREADY;
 	}
@@ -191,6 +191,7 @@ static int cmd_net_udp_send(const struct shell *sh, size_t argc, char *argv[])
 	uint16_t port;
 	uint8_t *payload = NULL;
 	int ret;
+	bool should_release_ctx = false;
 
 	struct net_if *iface;
 	struct sockaddr addr;
@@ -210,23 +211,21 @@ static int cmd_net_udp_send(const struct shell *sh, size_t argc, char *argv[])
 		return -EINVAL;
 	}
 
-	if (udp_ctx && net_context_is_used(udp_ctx)) {
-		PR_WARNING("Network context already in use\n");
-		return -EALREADY;
-	}
-
 	memset(&addr, 0, sizeof(addr));
 	ret = net_ipaddr_parse(host, strlen(host), &addr);
 	if (ret < 0) {
 		PR_WARNING("Cannot parse address \"%s\"\n", host);
 		return ret;
 	}
 
-	ret = net_context_get(addr.sa_family, SOCK_DGRAM, IPPROTO_UDP,
-			      &udp_ctx);
-	if (ret < 0) {
-		PR_WARNING("Cannot get UDP context (%d)\n", ret);
-		return ret;
+	/* Re-use already bound context if possible, or allocate temporary one. */
+	if (udp_ctx == NULL || !net_context_is_used(udp_ctx)) {
+		ret = net_context_get(addr.sa_family, SOCK_DGRAM, IPPROTO_UDP, &udp_ctx);
+		if (ret < 0) {
+			PR_WARNING("Cannot get UDP context (%d)\n", ret);
+			return ret;
+		}
+		should_release_ctx = true;
 	}
 
 	udp_shell = sh;
@@ -274,9 +273,11 @@ static int cmd_net_udp_send(const struct shell *sh, size_t argc, char *argv[])
 	}
 
 release_ctx:
-	ret = net_context_put(udp_ctx);
-	if (ret < 0) {
-		PR_WARNING("Cannot put UDP context (%d)\n", ret);
+	if (should_release_ctx) {
+		ret = net_context_put(udp_ctx);
+		if (ret < 0) {
+			PR_WARNING("Cannot put UDP context (%d)\n", ret);
+		}
 	}
 
 	return 0;