From: Álvaro Fernández Rojas <noltari@gmail.com>
Date: Fri, 14 Nov 2025 06:57:21 +0000 (+0100)
Subject: src: consolidate and improve fallthrough
X-Git-Url: http://git.openwrt.org/?a=commitdiff_plain;h=8a8bb3c1a673e567c438472339084943df72540b;p=project%2Fodhcpd.git

src: consolidate and improve fallthrough

- Enable fallthrough warnings.
- Use fallthrough attribute instead of comments.
- Drop unneeded fallthroughs (no code between two case statements).

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Link: https://github.com/openwrt/odhcpd/pull/307
---

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 34d6ea4..703d6b1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -30,6 +30,7 @@ target_compile_options(${PROJECT_NAME} PRIVATE -Werror=implicit-function-declara
 target_compile_options(${PROJECT_NAME} PRIVATE -Wformat)
 target_compile_options(${PROJECT_NAME} PRIVATE -Werror=format-security)
 target_compile_options(${PROJECT_NAME} PRIVATE -Werror=format-nonliteral)
+target_compile_options(${PROJECT_NAME} PRIVATE -Wimplicit-fallthrough=5)
 target_compile_options(${PROJECT_NAME} PRIVATE -Wno-unused-parameter)
 target_compile_options(${PROJECT_NAME} PRIVATE -Wmissing-declarations)
 
diff --git a/src/config.c b/src/config.c
index ff93da7..27ab531 100644
--- a/src/config.c
+++ b/src/config.c
@@ -1011,14 +1011,12 @@ static int parse_dnr_str(char *str, struct interface *iface)
 			break;
 
 		case DNR_SVC_NO_DEFAULT_ALPN:
-			/* fall through */
-
 		case DNR_SVC_OHTTP:
 			if (strlen(svc_val_str) > 0) {
 				error("Invalid value '%s' for SvcParam 'port'", svc_val_str);
 				goto err;
 			}
-			/* fall through */
+			_fallthrough;
 
 		case DNR_SVC_DOHPATH:
 			/* plain string */
@@ -1042,8 +1040,6 @@ static int parse_dnr_str(char *str, struct interface *iface)
 			goto err;
 
 		case DNR_SVC_IPV4HINT:
-			/* fall through */
-
 		case DNR_SVC_IPV6HINT:
 			error("SvcParam '%s' is not allowed", svc_param_key_names[svc_key]);
 			goto err;
diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index d1811ec..2229197 100644
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -578,8 +578,6 @@ dhcpv4_lease(struct interface *iface, enum dhcpv4_msg req_msg, const uint8_t *re
 		break;
 
 	case DHCPV4_MSG_DISCOVER:
-		_fallthrough;
-
 	case DHCPV4_MSG_REQUEST:
 		if (!lease && iface->no_dynamic_dhcp && !lease_cfg)
 			return NULL;
@@ -1013,7 +1011,6 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 	case DHCPV4_MSG_INFORM:
 		break;
 	case DHCPV4_MSG_DECLINE:
-		_fallthrough;
 	case DHCPV4_MSG_RELEASE:
 		dhcpv4_lease(iface, req_msg, req->chaddr, req_clientid,
 			     req_clientid_len, req_addr, &req_leasetime,
@@ -1021,7 +1018,6 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 			     &reply_incl_fr, &fr_serverid);
 		return;
 	case DHCPV4_MSG_DISCOVER:
-		_fallthrough;
 	case DHCPV4_MSG_REQUEST:
 		lease = dhcpv4_lease(iface, req_msg, req->chaddr, req_clientid,
 				     req_clientid_len, req_addr, &req_leasetime,
diff --git a/src/ndp.c b/src/ndp.c
index 58ed5f4..6924602 100644
--- a/src/ndp.c
+++ b/src/ndp.c
@@ -244,13 +244,13 @@ static void ndp_netevent_cb(unsigned long event, struct netevent_handler_info *i
 	case NETEV_ADDR6_DEL:
 		add = false;
 		netlink_dump_neigh_table(false);
-		/* fall through */
+		_fallthrough;
 	case NETEV_ADDR6_ADD:
 		setup_addr_for_relaying(&info->addr.in6, iface, add);
 		break;
 	case NETEV_NEIGH6_DEL:
 		add = false;
-		/* fall through */
+		_fallthrough;
 	case NETEV_NEIGH6_ADD:
 		if (info->neigh.flags & NTF_PROXY) {
 			if (add) {
diff --git a/src/netlink.c b/src/netlink.c
index c612884..9ef1a28 100644
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -452,21 +452,21 @@ static int cb_rtnl_valid(struct nl_msg *msg, _unused void *arg)
 
 	case RTM_NEWROUTE:
 		add = true;
-		/* fall through */
+		_fallthrough;
 	case RTM_DELROUTE:
 		ret = handle_rtm_route(hdr, add);
 		break;
 
 	case RTM_NEWADDR:
 		add = true;
-		/* fall through */
+		_fallthrough;
 	case RTM_DELADDR:
 		ret = handle_rtm_addr(hdr, add);
 		break;
 
 	case RTM_NEWNEIGH:
 		add = true;
-		/* fall through */
+		_fallthrough;
 	case RTM_DELNEIGH:
 		ret = handle_rtm_neigh(hdr, add);
 		break;