refactor: move variable declarations to function beginnings

src/packet/build.c

@@ -16,16 +16,19 @@ icmp_build_packet(void *buffer, size_t buffer_len, uint8_t type, uint8_t code,
 					size_t payload_len)
 {
 	const size_t required_len = sizeof(struct icmp_header) + payload_len;
+	struct icmp_header *h;
 
 	if (buffer_len < required_len)
 		return -1;
 
-	struct icmp_header *h = (struct icmp_header *)buffer;
+	h = (struct icmp_header *)buffer;
 
 	write_icmp_header(h, type, code, header_rest);
 	if (payload_len > 0)
+	{
 		memcpy((uint8_t *)buffer + sizeof(struct icmp_header), payload,
 				payload_len);
+	}
 
 	h->checksum = htons(icmp_checksum(h, required_len));
 

src/packet/parse_icmp.c

@@ -18,12 +18,15 @@ icmp_parse_icmp_payload(const void *buffer, size_t buffer_len,
 						size_t ip_hdr_len, uint8_t *type, uint8_t *code,
 						const void **payload, size_t *payload_len)
 {
+	size_t payload_offset;
+	const struct icmp_header *hdr;
+
 	if (validate_icmp_size(buffer_len, ip_hdr_len) != 0)
 		return -1;
 
-	const struct icmp_header *hdr = get_icmp_header(buffer, ip_hdr_len);
+	hdr = get_icmp_header(buffer, ip_hdr_len);
 	extract_icmp_fields(hdr, type, code);
-	size_t payload_offset = ip_hdr_len + ICMP_HEADER_SIZE;
+	payload_offset = ip_hdr_len + ICMP_HEADER_SIZE;
 
 	*payload_len = buffer_len - payload_offset;
 	*payload = (const uint8_t *)buffer + payload_offset;

src/packet/parse_ip.c

@@ -18,11 +18,14 @@ icmp_parse_ip_header(const void *buffer, size_t buffer_len, uint8_t *ttl,
 						struct in_addr *src_addr, size_t *ip_hdr_len,
 						struct in_addr *dst_addr, uint8_t *protocol)
 {
+	const struct ip_header *h;
+	size_t ihl_bytes;
+
 	if (buffer_len < MIN_IP_HEADER_SIZE)
 		return -1;
 
-	const struct ip_header *h = (const struct ip_header *)buffer;
-	size_t ihl_bytes = extract_ip_header_length(h->version_ihl);
+	h = (const struct ip_header *)buffer;
+	ihl_bytes = extract_ip_header_length(h->version_ihl);
 
 	if (0 != validate_ip_header(h, buffer_len))
 		return -1;

src/send/api/raw.c

@@ -19,15 +19,17 @@ icmp_send_raw(icmp_handle_t *h, uint8_t type, uint8_t code,
 				const void *payload, size_t len, struct in_addr dest,
 				uint8_t ttl)
 {
+	uint8_t buffer[ICMP_HEADER_SIZE + MAX_PAYLOAD_SIZE];
+	int packet_len;
+
 	if (0 == send_validate_handle(h))
 		return -1;
 
 	if (0 == validate_payload(h, payload, len))
 		return -1;
 
-	uint8_t buffer[ICMP_HEADER_SIZE + MAX_PAYLOAD_SIZE];
 
-	int packet_len = icmp_build_packet(buffer, sizeof(buffer),
+	packet_len = icmp_build_packet(buffer, sizeof(buffer),
 			type, code, header_rest, payload, len);
 	if (-1 == packet_len)
 	{

src/send/core/send_to_destination.c

@@ -6,10 +6,11 @@ int
 send_to_destination(struct icmp_handle *h, const void *packet, size_t len,
 					struct in_addr dest, uint8_t ttl)
 {
+	struct sockaddr_in addr;
+
 	if (send_set_socket_ttl(h, ttl) < 0)
 		return -1;
 
-	struct sockaddr_in addr;
 	send_prepare_destination(&addr, dest);
 
 	if (send_packet(h, packet, len, &addr) < 0)

src/send/helpers/set_socket_ttl.c

@@ -8,10 +8,11 @@ int
 send_set_socket_ttl(struct icmp_handle *h, uint8_t ttl)
 {
 	int ttl_val = ttl;
+	int saved_errno;
 
 	if (setsockopt(h->fd, IPPROTO_IP, IP_TTL, &ttl_val, sizeof(ttl_val)) < 0)
 	{
-		int saved_errno = errno;
+		saved_errno = errno;
 		icmp_set_error_fmt(h, ICMP_ERR_SOCKET, "Failed to set TTL: %s",
 						strerror(saved_errno));
 		return -1;

src/socket/configure.c

@@ -13,7 +13,6 @@ socket_configure(struct icmp_handle *h)
 {
 	int flags;
 
-	/* Get current file status flags */
 	flags = fcntl(h->fd, F_GETFL, 0);
 	if (-1 == flags)
 	{
@@ -21,14 +20,12 @@ socket_configure(struct icmp_handle *h)
 		return -1;
 	}
 
-	/* Set non-blocking flag */
 	if (-1 == fcntl(h->fd, F_SETFL, flags | O_NONBLOCK))
 	{
 		handle_configure_error(h, "fcntl(F_SETFL)");
 		return -1;
 	}
 
-	/* Clear error state on success */
 	icmp_clear_error(h);
 
 	return 0;

src/socket/create.c

@@ -14,7 +14,6 @@ socket_create(struct icmp_handle *h)
 {
 	int fd;
 
-	/* Create raw ICMP socket */
 	fd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
 
 	if (fd < 0)
@@ -23,10 +22,8 @@ socket_create(struct icmp_handle *h)
 		return -1;
 	}
 
-	/* Store file descriptor in handle */
 	h->fd = fd;
 
-	/* Clear error state on success */
 	icmp_clear_error(h);
 
 	return 0;

src/utils/checksum.c

@@ -24,8 +24,8 @@ static uint32_t
 sum_words(const uint8_t *data, size_t len)
 {
 	const uint8_t *ptr = data;
+	const size_t words = len >> 1;
 	uint32_t sum = 0;
-	size_t words = len >> 1;
 
 	/* Duff's device: unroll loop by 4 */
 	if (words > 0)