build: add -Wimplicit-fallthrough

bgpd/bgp_aspath.c

@@ -1892,7 +1892,7 @@ struct aspath *aspath_reconcile_as4(struct aspath *aspath,
 						"[AS4] AS4PATHmangle: AS_CONFED_SEQUENCE falls across 2/4 ASN boundary somewhere, broken..");
 				hops = seg->length;
 			}
-		/* fallthru */
+			fallthrough;
 		case AS_SEQUENCE:
 			cpasns = MIN(seg->length, hops);
 			hops -= seg->length;

bgpd/bgp_attr.c

@@ -2323,11 +2323,8 @@ int bgp_mp_reach_parse(struct bgp_attr_parser_args *args,
 				/*
 				 * NOTE: intentional fall through
 				 * - for consistency in rx processing
-				 *
-				 * The following comment is to signal GCC this intention
-				 * and suppress the warning
 				 */
-	/* FALLTHRU */
+		fallthrough;
 	case BGP_ATTR_NHLEN_IPV4:
 		stream_get(&attr->mp_nexthop_global_in, s, IPV4_MAX_BYTELEN);
 		/* Probably needed for RFC 2283 */

bgpd/bgp_clist.c

@@ -128,6 +128,7 @@ static void community_entry_free(struct community_entry *entry)
 		XFREE(MTYPE_COMMUNITY_LIST_CONFIG, entry->config);
 		if (entry->reg)
 			bgp_regex_free(entry->reg);
+		break;
 	default:
 		break;
 	}

bgpd/bgp_fsm.c

@@ -445,7 +445,7 @@ void bgp_timer_set(struct peer_connection *connection)
 
 		EVENT_OFF(peer->connection->t_pmax_restart);
 		EVENT_OFF(peer->t_refresh_stalepath);
-	/* fallthru */
+		fallthrough;
 	case Clearing:
 		EVENT_OFF(connection->t_start);
 		EVENT_OFF(connection->t_connect);
@@ -2384,6 +2384,7 @@ void bgp_fsm_nht_update(struct peer_connection *connection, struct peer *peer,
 		    && (peer->gtsm_hops == BGP_GTSM_HOPS_CONNECTED
 			|| peer->bgp->fast_convergence))
 			BGP_EVENT_ADD(connection, TCP_fatal_error);
+		break;
 	case Clearing:
 	case Deleted:
 	case BGP_STATUS_MAX:

bgpd/bgp_open.c

@@ -1028,6 +1028,7 @@ static int bgp_capability_parse(struct peer *peer, size_t length,
 						BGP_NOTIFY_OPEN_MALFORMED_ATTR);
 				return -1;
 			}
+			break;
 		/* we deliberately ignore unknown codes, see below */
 		default:
 			break;

bgpd/bgp_routemap_nb_config.c

@@ -1747,7 +1747,7 @@ int lib_route_map_entry_set_action_rmap_set_action_ipv6_address_modify(
 			    || IN6_IS_ADDR_LINKLOCAL(&i6a))
 				return NB_ERR_VALIDATION;
 		}
-	/* FALLTHROUGH */
+		return NB_OK;
 	case NB_EV_PREPARE:
 	case NB_EV_ABORT:
 		return NB_OK;

bgpd/bgpd.c

@@ -186,7 +186,6 @@ int bgp_option_set(int flag)
 int bgp_option_unset(int flag)
 {
 	switch (flag) {
-	/* Fall through.  */
 	case BGP_OPT_NO_ZEBRA:
 	case BGP_OPT_NO_FIB:
 		UNSET_FLAG(bm->options, flag);

bgpd/rfapi/bgp_rfapi_cfg.c

@@ -1720,7 +1720,8 @@ DEFUN (vnc_nve_group_export_no_routemap,
 	switch (argv[idx]->text[0]) {
 	case 'z':
 		is_bgp = 0;
-	/* fall thru */
+		idx += 2;
+		break;
 	case 'b':
 		idx += 2;
 		break;
@@ -3590,7 +3591,9 @@ DEFUN (vnc_l2_group_rt,
 
 	switch (argv[1]->arg[0]) {
 	case 'b':
-		do_export = 1; /* fall through */
+		do_export = 1;
+		do_import = 1;
+		break;
 	case 'i':
 		do_import = 1;
 		break;

bgpd/rfapi/rfapi_vty.c

@@ -4151,6 +4151,7 @@ static int rfapi_vty_show_nve_summary(struct vty *vty,
 
 		case SHOW_NVE_SUMMARY_RESPONSES:
 			rfapiRibShowResponsesSummary(vty);
+			break;
 
 		case SHOW_NVE_SUMMARY_UNKNOWN_NVES:
 		case SHOW_NVE_SUMMARY_MAX:

configure.ac

@@ -365,6 +365,7 @@ AC_C_FLAG([-Wpointer-arith])
 AC_C_FLAG([-Wbad-function-cast])
 AC_C_FLAG([-Wwrite-strings])
 AC_C_FLAG([-Wundef])
+AC_C_FLAG([-Wimplicit-fallthrough])
 if test "$enable_gcc_ultra_verbose" = "yes" ; then
   AC_C_FLAG([-Wcast-qual])
   AC_C_FLAG([-Wmissing-noreturn])

ldpd/init.c

@@ -229,7 +229,7 @@ send_capability(struct nbr *nbr, uint16_t capability, int enable)
 		 * Announcement Parameter in Capability messages sent to
 		 * its peers".
 		 */
-		/* FALLTHROUGH */
+		fallthrough;
 	default:
 		fatalx("send_capability: unsupported capability");
 	}
@@ -333,7 +333,7 @@ recv_capability(struct nbr *nbr, char *buf, uint16_t len)
 			 * parameter and process any other Capability Parameters
 			 * in the message".
 			 */
-			/* FALLTHROUGH */
+			fallthrough;
 		default:
 			if (!CHECK_FLAG(ntohs(tlv.type), UNKNOWN_FLAG))
 				send_notification_rtlvs(nbr, S_UNSSUPORTDCAP,

ldpd/ldp_vty_exec.c

@@ -1106,7 +1106,7 @@ show_lib_msg(struct vty *vty, struct imsg *imsg, struct show_params *params)
 		if (params->lib.remote_label != NO_LABEL &&
 		    params->lib.remote_label != rt->remote_label)
 			return (0);
-		/* FALLTHROUGH */
+		fallthrough;
 	case IMSG_CTL_SHOW_LIB_RCVD:
 		rt = imsg->data;
 

ldpd/neighbor.c

@@ -505,21 +505,12 @@ nbr_start_idtimer(struct nbr *nbr)
 {
 	int	secs;
 
-	secs = INIT_DELAY_TMR;
-	switch(nbr->idtimer_cnt) {
-	default:
+	if (nbr->idtimer_cnt > 2) {
 		/* do not further increase the counter */
 		secs = MAX_DELAY_TMR;
-		break;
-	case 2:
-		secs *= 2;
-		/* FALLTHROUGH */
-	case 1:
-		secs *= 2;
-		/* FALLTHROUGH */
-	case 0:
+	} else {
+		secs = INIT_DELAY_TMR * (1 << nbr->idtimer_cnt);
 		nbr->idtimer_cnt++;
-		break;
 	}
 
 	EVENT_OFF(nbr->initdelay_timer);

lib/base64.c

@@ -9,6 +9,7 @@
 #endif
 
 #include "base64.h"
+#include "compiler.h"
 
 static const int CHARS_PER_LINE = 72;
 static const char *ENCODING =
@@ -41,6 +42,7 @@ int base64_encode_block(const char *plaintext_in, int length_in, char *code_out,
 
 	switch (state_in->step) {
 		while (1) {
+			fallthrough;
 			case step_A:
 				if (plainchar == plaintextend) {
 					state_in->result = result;
@@ -51,7 +53,7 @@ int base64_encode_block(const char *plaintext_in, int length_in, char *code_out,
 				result = (fragment & 0x0fc) >> 2;
 				*codechar++ = base64_encode_value(result);
 				result = (fragment & 0x003) << 4;
-				/* fall through */
+				fallthrough;
 			case step_B:
 				if (plainchar == plaintextend) {
 					state_in->result = result;
@@ -62,7 +64,7 @@ int base64_encode_block(const char *plaintext_in, int length_in, char *code_out,
 				result |= (fragment & 0x0f0) >> 4;
 				*codechar++ = base64_encode_value(result);
 				result = (fragment & 0x00f) << 2;
-				/* fall through */
+				fallthrough;
 			case step_C:
 				if (plainchar == plaintextend) {
 					state_in->result = result;
@@ -146,6 +148,7 @@ int base64_decode_block(const char *code_in, int length_in, char *plaintext_out,
 
 	switch (state_in->step) {
 		while (1) {
+			fallthrough;
 			case step_a:
 				do {
 					if (codec == code_in+length_in) {
@@ -156,7 +159,7 @@ int base64_decode_block(const char *code_in, int length_in, char *plaintext_out,
 					fragmt = base64_decode_value(*codec++);
 				} while (fragmt < 0);
 				*plainc = (fragmt & 0x03f) << 2;
-				/* fall through */
+				fallthrough;
 			case step_b:
 				do {
 					if (codec == code_in+length_in) {
@@ -168,7 +171,7 @@ int base64_decode_block(const char *code_in, int length_in, char *plaintext_out,
 				} while (fragmt < 0);
 				*plainc++ |= (fragmt & 0x030) >> 4;
 				*plainc = (fragmt & 0x00f) << 4;
-				/* fall through */
+				fallthrough;
 			case step_c:
 				do {
 					if (codec == code_in+length_in) {
@@ -180,7 +183,7 @@ int base64_decode_block(const char *code_in, int length_in, char *plaintext_out,
 				} while (fragmt < 0);
 				*plainc++ |= (fragmt & 0x03c) >> 2;
 				*plainc = (fragmt & 0x003) << 6;
-				/* fall through */
+				fallthrough;
 			case step_d:
 				do {
 					if (codec == code_in+length_in) {

lib/command_match.c

@@ -405,10 +405,10 @@ enum matcher_rv command_complete(struct graph *graph, vector vline,
 				listnode_add(next, newstack);
 				break;
 			case partly_match:
-				trace_matcher("trivial_match\n");
+				trace_matcher("partly_match\n");
 				if (exact_match_exists && !last_token)
 					break;
-			/* fallthru */
+				fallthrough;
 			case exact_match:
 				trace_matcher("exact_match\n");
 				if (last_token) {

lib/compiler.h

@@ -33,7 +33,7 @@ extern "C" {
 #  define _RET_NONNULL    , returns_nonnull
 #endif
 #if __has_attribute(fallthrough)
-#  define _FALLTHROUGH __attribute__((fallthrough));
+#  define fallthrough __attribute__((fallthrough));
 #endif
 # define _CONSTRUCTOR(x)  constructor(x)
 # define _DEPRECATED(x) deprecated(x)
@@ -57,7 +57,7 @@ extern "C" {
 #  define __has_attribute(x) 0
 #endif
 #if __GNUC__ >= 7
-#  define _FALLTHROUGH __attribute__((fallthrough));
+#  define fallthrough __attribute__((fallthrough));
 #endif
 #endif
 
@@ -112,8 +112,8 @@ extern "C" {
 #ifndef _ALLOC_SIZE
 # define _ALLOC_SIZE(x)
 #endif
-#ifndef _FALLTHROUGH
-#define _FALLTHROUGH
+#ifndef fallthrough
+#define fallthrough
 #endif
 #ifndef _DEPRECATED
 #define _DEPRECATED(x) deprecated

lib/jhash.c

@@ -86,34 +86,34 @@ uint32_t jhash(const void *key, uint32_t length, uint32_t initval)
 	switch (len) {
 	case 11:
 		c += ((uint32_t)k[10] << 24);
-	/* fallthru */
+		fallthrough;
 	case 10:
 		c += ((uint32_t)k[9] << 16);
-	/* fallthru */
+		fallthrough;
 	case 9:
 		c += ((uint32_t)k[8] << 8);
-	/* fallthru */
+		fallthrough;
 	case 8:
 		b += ((uint32_t)k[7] << 24);
-	/* fallthru */
+		fallthrough;
 	case 7:
 		b += ((uint32_t)k[6] << 16);
-	/* fallthru */
+		fallthrough;
 	case 6:
 		b += ((uint32_t)k[5] << 8);
-	/* fallthru */
+		fallthrough;
 	case 5:
 		b += k[4];
-	/* fallthru */
+		fallthrough;
 	case 4:
 		a += ((uint32_t)k[3] << 24);
-	/* fallthru */
+		fallthrough;
 	case 3:
 		a += ((uint32_t)k[2] << 16);
-	/* fallthru */
+		fallthrough;
 	case 2:
 		a += ((uint32_t)k[1] << 8);
-	/* fallthru */
+		fallthrough;
 	case 1:
 		a += k[0];
 	}
@@ -148,7 +148,7 @@ uint32_t jhash2(const uint32_t *k, uint32_t length, uint32_t initval)
 	switch (len) {
 	case 2:
 		b += k[1];
-	/* fallthru */
+		fallthrough;
 	case 1:
 		a += k[0];
 	}

lib/libfrr.c

@@ -218,7 +218,8 @@ bool frr_zclient_addr(struct sockaddr_storage *sa, socklen_t *sa_len,
 			break;
 		case '6':
 			path++;
-		/* fallthrough */
+			af = AF_INET6;
+			break;
 		default:
 			af = AF_INET6;
 			break;

lib/nexthop.c

@@ -173,7 +173,7 @@ static int _nexthop_cmp_no_labels(const struct nexthop *next1,
 		ret = _nexthop_gateway_cmp(next1, next2);
 		if (ret != 0)
 			return ret;
-		/* Intentional Fall-Through */
+		fallthrough;
 	case NEXTHOP_TYPE_IFINDEX:
 		if (next1->ifindex < next2->ifindex)
 			return -1;
@@ -295,7 +295,7 @@ int nexthop_cmp_basic(const struct nexthop *nh1,
 		ret = nexthop_g_addr_cmp(nh1->type, &nh1->gate, &nh2->gate);
 		if (ret != 0)
 			return ret;
-		/* Intentional Fall-Through */
+		fallthrough;
 	case NEXTHOP_TYPE_IFINDEX:
 		if (nh1->ifindex < nh2->ifindex)
 			return -1;

lib/nexthop_group.c

@@ -180,7 +180,7 @@ static struct nexthop *nhg_nh_find(const struct nexthop_group *nhg,
 						 &nexthop->gate, &nh->gate);
 			if (ret != 0)
 				continue;
-			/* Intentional Fall-Through */
+			fallthrough;
 		case NEXTHOP_TYPE_IFINDEX:
 			if (nexthop->ifindex != nh->ifindex)
 				continue;