src: fix shadowed local variables

Fix shadowed local variables and enable warning to prevent more shadowed
variables in the future.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

7 files changed, 48 insertions, 40 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 703d6b1..06b9af4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -31,8 +31,10 @@ 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(${PROJECT_NAME} PRIVATE -Wno-shadow=compatible-local)
 target_compile_options(${PROJECT_NAME} PRIVATE -Wno-unused-parameter)
 target_compile_options(${PROJECT_NAME} PRIVATE -Wmissing-declarations)
+target_compile_options(${PROJECT_NAME} PRIVATE -Wshadow=local)
 
 
 # Libraries
diff --git a/src/config.c b/src/config.c
index ec110b5..f5773dc 100644
--- a/src/config.c
+++ b/src/config.c
@@ -1387,7 +1387,7 @@ int config_parse_interface(void *data, size_t len, const char *name, bool overwr
 			uint8_t buf[DNS_MAX_NAME_LEN];
 			char *domain;
 			size_t domainlen;
-			int len;
+			int ds_len;
 			uint8_t *tmp;
 
 			if (blobmsg_type(cur) != BLOBMSG_TYPE_STRING || !blobmsg_check_attr(cur, false))
@@ -1399,20 +1399,20 @@ int config_parse_interface(void *data, size_t len, const char *name, bool overwr
 			if (domainlen > 0 && domain[domainlen - 1] == '.')
 				domain[domainlen - 1] = 0;
 
-			len = dn_comp(domain, buf, sizeof(buf), NULL, NULL);
-			if (len <= 0) {
+			ds_len = dn_comp(domain, buf, sizeof(buf), NULL, NULL);
+			if (ds_len <= 0) {
 				error("Invalid %s value configured for interface '%s'",
 				      iface_attrs[IFACE_ATTR_DNS_DOMAIN_SEARCH].name, iface->name);
 				continue;
 			}
 
-			tmp = realloc(iface->dns_search, iface->dns_search_len + len);
+			tmp = realloc(iface->dns_search, iface->dns_search_len + ds_len);
 			if (!tmp)
 				goto err;
 
 			iface->dns_search = tmp;
-			memcpy(&iface->dns_search[iface->dns_search_len], buf, len);
-			iface->dns_search_len += len;
+			memcpy(&iface->dns_search[iface->dns_search_len], buf, ds_len);
+			iface->dns_search_len += ds_len;
 		}
 	}
 
diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index 17c34ba..5afeb91 100644
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -1095,9 +1095,9 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 
 	/* Note: each option might get called more than once */
 	for (size_t i = 0; i < sizeof(std_opts) + req_opts_len; i++) {
-		uint8_t opt = i < sizeof(std_opts) ? std_opts[i] : req_opts[i - sizeof(std_opts)];
+		uint8_t r_opt = i < sizeof(std_opts) ? std_opts[i] : req_opts[i - sizeof(std_opts)];
 
-		switch (opt) {
+		switch (r_opt) {
 		case DHCPV4_OPT_NETMASK:
 			if (!lease)
 				break;
@@ -1216,20 +1216,20 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 				iov[IOV_SRCH_DOMAIN_NAME].iov_base = iface->dns_search;
 				iov[IOV_SRCH_DOMAIN_NAME].iov_len = iface->dns_search_len;
 			} else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
-				int len;
+				int dds_len;
 
 				if (!iov[IOV_SRCH_DOMAIN_NAME].iov_base)
 					iov[IOV_SRCH_DOMAIN_NAME].iov_base = alloca(DNS_MAX_NAME_LEN);
 
-				len = dn_comp(_res.dnsrch[0],
+				dds_len = dn_comp(_res.dnsrch[0],
 					      iov[IOV_SRCH_DOMAIN_NAME].iov_base,
 					      DNS_MAX_NAME_LEN, NULL, NULL);
-				if (len < 0)
+				if (dds_len < 0)
 					break;
 
-				reply_srch_domain.len = len;
+				reply_srch_domain.len = dds_len;
 				iov[IOV_SRCH_DOMAIN].iov_len = sizeof(reply_srch_domain);
-				iov[IOV_SRCH_DOMAIN_NAME].iov_len = len;
+				iov[IOV_SRCH_DOMAIN_NAME].iov_len = dds_len;
 			}
 			break;
 
@@ -1247,8 +1247,8 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 			if (!lease || reply_dnr.len > 0)
 				break;
 
-			for (size_t i = 0; i < iface->dnr_cnt; i++) {
-				struct dnr_options *dnr = &iface->dnr[i];
+			for (size_t j = 0; j < iface->dnr_cnt; j++) {
+				struct dnr_options *dnr = &iface->dnr[j];
 
 				if (dnr->addr4_cnt == 0 && dnr->addr6_cnt > 0)
 					continue;
@@ -1269,8 +1269,8 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 			dnrs = alloca(dnrs_len);
 			uint8_t *pos = (uint8_t *)dnrs;
 
-			for (size_t i = 0; i < iface->dnr_cnt; i++) {
-				struct dnr_options *dnr = &iface->dnr[i];
+			for (size_t j = 0; j < iface->dnr_cnt; j++) {
+				struct dnr_options *dnr = &iface->dnr[j];
 				struct dhcpv4_dnr *d4dnr = (struct dhcpv4_dnr *)pos;
 				uint16_t d4dnr_len = sizeof(uint16_t) + sizeof(uint8_t) + dnr->adn_len;
 				uint16_t d4dnr_priority_be = htons(dnr->priority);
@@ -1319,13 +1319,13 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 				break;
 
 			uint8_t *buf = alloca(2 + uri_len);
-			struct dhcpv4_option *opt = (struct dhcpv4_option *)buf;
+			struct dhcpv4_option *cp_opt = (struct dhcpv4_option *)buf;
 
-			opt->code = DHCPV4_OPT_CAPTIVE_PORTAL;
-			opt->len  = uri_len;
-			memcpy(opt->data, iface->captive_portal_uri, uri_len);
+			cp_opt->code = DHCPV4_OPT_CAPTIVE_PORTAL;
+			cp_opt->len  = uri_len;
+			memcpy(cp_opt->data, iface->captive_portal_uri, uri_len);
 
-			iov[IOV_CAPTIVE_PORTAL].iov_base = opt;
+			iov[IOV_CAPTIVE_PORTAL].iov_base = cp_opt;
 			iov[IOV_CAPTIVE_PORTAL].iov_len  = 2 + uri_len;
 			break;
 		}
diff --git a/src/dhcpv6-ia.c b/src/dhcpv6-ia.c
index 87b124b..ca3f89d 100644
--- a/src/dhcpv6-ia.c
+++ b/src/dhcpv6-ia.c
@@ -1002,7 +1002,7 @@ ssize_t dhcpv6_ia_handle_IAs(uint8_t *buf, size_t buflen, struct interface *ifac
 		if (is_pd) {
 			uint8_t *sdata;
 			uint16_t stype, slen;
-			dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
+			dhcpv6_for_each_sub_option(&ia[1], odata + olen, stype, slen, sdata) {
 				if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
 					continue;
 
@@ -1045,7 +1045,7 @@ ssize_t dhcpv6_ia_handle_IAs(uint8_t *buf, size_t buflen, struct interface *ifac
 		} else if (is_na) {
 			uint8_t *sdata;
 			uint16_t stype, slen;
-			dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
+			dhcpv6_for_each_sub_option(&ia[1], odata + olen, stype, slen, sdata) {
 				if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
 					continue;
 
diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index 06b7f59..03537fd 100644
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -553,8 +553,8 @@ static void handle_client_request(void *addr, void *data, size_t len,
 			break;
 
 		case DHCPV6_OPT_DNR:
-			for (size_t i = 0; i < iface->dnr_cnt; i++) {
-				struct dnr_options *dnr = &iface->dnr[i];
+			for (size_t j = 0; j < iface->dnr_cnt; j++) {
+				struct dnr_options *dnr = &iface->dnr[j];
 
 				if (dnr->addr6_cnt == 0 && dnr->addr4_cnt > 0)
 					continue;
@@ -572,8 +572,8 @@ static void handle_client_request(void *addr, void *data, size_t len,
 			dnrs = alloca(dnrs_len);
 			uint8_t *pos = (uint8_t *)dnrs;
 
-			for (size_t i = 0; i < iface->dnr_cnt; i++) {
-				struct dnr_options *dnr = &iface->dnr[i];
+			for (size_t j = 0; j < iface->dnr_cnt; j++) {
+				struct dnr_options *dnr = &iface->dnr[j];
 				struct dhcpv6_dnr *d6dnr = (struct dhcpv6_dnr *)pos;
 				uint16_t d6dnr_type_be = htons(DHCPV6_OPT_DNR);
 				uint16_t d6dnr_len = 2 * sizeof(uint16_t) + dnr->adn_len;
@@ -620,11 +620,11 @@ static void handle_client_request(void *addr, void *data, size_t len,
 	size_t dns_search_len = iface->dns_search_len;
 
 	if (!dns_search && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
-		int len = dn_comp(_res.dnsrch[0], dns_search_buf,
+		int ds_len = dn_comp(_res.dnsrch[0], dns_search_buf,
 				sizeof(dns_search_buf), NULL, NULL);
-		if (len > 0) {
+		if (ds_len > 0) {
 			dns_search = dns_search_buf;
-			dns_search_len = len;
+			dns_search_len = ds_len;
 		}
 	}
 
@@ -874,10 +874,10 @@ static void relay_server_response(uint8_t *data, size_t len)
 	if (payload_data[0] == DHCPV6_MSG_RELAY_REPL) {
 		target.sin6_port = htons(DHCPV6_SERVER_PORT);
 	} else { /* Go through the payload data */
-		struct dhcpv6_client_header *h = (void*)payload_data;
+		struct dhcpv6_client_header *dch = (void*)payload_data;
 		end = payload_data + payload_len;
 
-		dhcpv6_for_each_option(&h[1], end, otype, olen, odata) {
+		dhcpv6_for_each_option(&dch[1], end, otype, olen, odata) {
 			if (otype == DHCPV6_OPT_DNS_SERVERS && olen >= sizeof(struct in6_addr)) {
 				dns_addrs6 = (struct in6_addr*)odata;
 				dns_addrs6_cnt = olen / sizeof(struct in6_addr);
diff --git a/src/dhcpv6.h b/src/dhcpv6.h
index 0a7628c..63301ac 100644
--- a/src/dhcpv6.h
+++ b/src/dhcpv6.h
@@ -167,10 +167,16 @@ struct dhcpv6_cer_id {
 	struct in6_addr addr;
 };
 
-#define dhcpv6_for_each_option(start, end, otype, olen, odata)\
-	for (uint8_t *_o = (uint8_t*)(start); _o + 4 <= (end) &&\
-		((otype) = _o[0] << 8 | _o[1]) && ((odata) = (void*)&_o[4]) &&\
+#define dhcpv6_for_each_option(start, end, otype, olen, odata) \
+	for (uint8_t *_o = (uint8_t*)(start); _o + 4 <= (end) && \
+		((otype) = _o[0] << 8 | _o[1]) && ((odata) = (void*)&_o[4]) && \
 		((olen) = _o[2] << 8 | _o[3]) + (odata) <= (end); \
 		_o += 4 + (_o[2] << 8 | _o[3]))
 
+#define dhcpv6_for_each_sub_option(start, end, otype, olen, odata) \
+	for (uint8_t *_so = (uint8_t*)(start); _so + 4 <= (end) && \
+		((otype) = _so[0] << 8 | _so[1]) && ((odata) = (void*)&_so[4]) && \
+		((olen) = _so[2] << 8 | _so[3]) + (odata) <= (end); \
+		_so += 4 + (_so[2] << 8 | _so[3]))
+
 #endif /* _DHCPV6_H_ */
diff --git a/src/router.c b/src/router.c
index b882e01..4fe8ccf 100644
--- a/src/router.c
+++ b/src/router.c
@@ -699,11 +699,11 @@ static int send_router_advert(struct interface *iface, const struct in6_addr *fr
 			continue; /* PIO filtered out of this RA */
 		}
 
-		for (size_t i = 0; i < pfxs_cnt; ++i) {
-			if (addr->prefix_len == pfxs[i].nd_opt_pi_prefix_len &&
-			    !odhcpd_bmemcmp(&pfxs[i].nd_opt_pi_prefix,
+		for (size_t j = 0; j < pfxs_cnt; ++j) {
+			if (addr->prefix_len == pfxs[j].nd_opt_pi_prefix_len &&
+			    !odhcpd_bmemcmp(&pfxs[j].nd_opt_pi_prefix,
 					    &addr->addr.in6, addr->prefix_len))
-				p = &pfxs[i];
+				p = &pfxs[j];
 		}
 
 		if (!p) {