diff --git a/src/Makefile b/src/Makefile
index 04cef2e..9026318 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -11,6 +11,7 @@ HEAD_COMMIT = `git rev-parse --short HEAD`
 LIBPATH = -L.
 LDFLAGS +=  -lz `sh osflags $(TARGETOS) link` $(LIBPATH)
 CFLAGS += -std=c99 -c -g -Wall -D$(OS) -pedantic `sh osflags $(TARGETOS) cflags` -DGITREVISION=\"$(HEAD_COMMIT)\"
+CFLAGS += -Wstrict-prototypes -Wtype-limits -Wmissing-declarations -Wmissing-prototypes
 
 all: stateos $(CLIENT) $(SERVER)
 
diff --git a/src/android_dns.h b/src/android_dns.h
index 5a86e71..051b1b8 100644
--- a/src/android_dns.h
+++ b/src/android_dns.h
@@ -47,7 +47,7 @@ typedef struct {
 
 #define C_IN		1
 
-#define T_A			1
+#define T_A		1
 #define T_CNAME		5
 #define T_NULL		10
 #define T_MX		15
diff --git a/src/base128.c b/src/base128.c
index be7ba86..8f926ed 100644
--- a/src/base128.c
+++ b/src/base128.c
@@ -54,9 +54,9 @@ static int reverse_init = 0;
 
 static int base128_encode(char *, size_t *, const void *, size_t);
 static int base128_decode(void *, size_t *, const char *, size_t);
-static int base128_handles_dots();
-static int base128_blksize_raw();
-static int base128_blksize_enc();
+static int base128_handles_dots(void);
+static int base128_blksize_raw(void);
+static int base128_blksize_enc(void);
 
 static struct encoder base128_encoder =
 {
@@ -69,32 +69,27 @@ static struct encoder base128_encoder =
 	base128_blksize_enc
 };
 
-struct encoder
-*get_base128_encoder()
+struct encoder *get_base128_encoder(void)
 {
 	return &base128_encoder;
 }
 
-static int
-base128_handles_dots()
+static int base128_handles_dots(void)
 {
 	return 0;
 }
 
-static int
-base128_blksize_raw()
+static int base128_blksize_raw(void)
 {
 	return BLKSIZE_RAW;
 }
 
-static int
-base128_blksize_enc()
+static int base128_blksize_enc(void)
 {
 	return BLKSIZE_ENC;
 }
 
-inline static void
-base128_reverse_init()
+inline static void base128_reverse_init(void)
 {
 	int i;
 	unsigned char c;
@@ -109,8 +104,6 @@ base128_reverse_init()
 	}
 }
 
-static int
-base128_encode(char *buf, size_t *buflen, const void *data, size_t size)
 /*
  * Fills *buf with max. *buflen characters, encoding size bytes of *data.
  *
@@ -120,6 +113,8 @@ base128_encode(char *buf, size_t *buflen, const void *data, size_t size)
  * return value    : #bytes filled in buf   (excluding \0)
  * sets *buflen to : #bytes encoded from data
  */
+static int base128_encode(char *buf, size_t *buflen, const void *data,
+			  size_t size)
 {
 	unsigned char *ubuf = (unsigned char *) buf;
 	unsigned char *udata = (unsigned char *) data;
@@ -203,8 +198,6 @@ base128_encode(char *buf, size_t *buflen, const void *data, size_t size)
 
 #define REV128(x) rev128[(int) (x)]
 
-static int
-base128_decode(void *buf, size_t *buflen, const char *str, size_t slen)
 /*
  * Fills *buf with max. *buflen bytes, decoded from slen chars in *str.
  * Decoding stops early when *str contains \0.
@@ -216,6 +209,8 @@ base128_decode(void *buf, size_t *buflen, const char *str, size_t slen)
  *
  * return value    : #bytes filled in buf   (excluding \0)
  */
+static int base128_decode(void *buf, size_t *buflen, const char *str,
+			  size_t slen)
 {
 	unsigned char *ustr = (unsigned char *) str;
 	unsigned char *ubuf = (unsigned char *) buf;
diff --git a/src/base32.c b/src/base32.c
index a058d38..bf540eb 100644
--- a/src/base32.c
+++ b/src/base32.c
@@ -35,9 +35,9 @@ static int reverse_init = 0;
 
 static int base32_encode(char *, size_t *, const void *, size_t);
 static int base32_decode(void *, size_t *, const char *, size_t);
-static int base32_handles_dots();
-static int base32_blksize_raw();
-static int base32_blksize_enc();
+static int base32_handles_dots(void);
+static int base32_blksize_raw(void);
+static int base32_blksize_enc(void);
 
 static struct encoder base32_encoder =
 {
@@ -50,32 +50,27 @@ static struct encoder base32_encoder =
 	base32_blksize_enc
 };
 
-struct encoder
-*get_base32_encoder()
+struct encoder *get_base32_encoder(void)
 {
 	return &base32_encoder;
 }
 
-static int
-base32_handles_dots()
+static int base32_handles_dots(void)
 {
 	return 0;
 }
 
-static int
-base32_blksize_raw()
+static int base32_blksize_raw(void)
 {
 	return BLKSIZE_RAW;
 }
 
-static int
-base32_blksize_enc()
+static int base32_blksize_enc(void)
 {
 	return BLKSIZE_ENC;
 }
 
-inline static void
-base32_reverse_init()
+inline static void base32_reverse_init(void)
 {
 	int i;
 	unsigned char c;
@@ -92,21 +87,17 @@ base32_reverse_init()
 	}
 }
 
-int
-b32_5to8(int in)
+int b32_5to8(int in)
 {
 	return cb32[in & 31];
 }
 
-int
-b32_8to5(int in)
+int b32_8to5(int in)
 {
 	base32_reverse_init();
 	return rev32[in];
 }
 
-static int
-base32_encode(char *buf, size_t *buflen, const void *data, size_t size)
 /*
  * Fills *buf with max. *buflen characters, encoding size bytes of *data.
  *
@@ -116,6 +107,7 @@ base32_encode(char *buf, size_t *buflen, const void *data, size_t size)
  * return value    : #bytes filled in buf   (excluding \0)
  * sets *buflen to : #bytes encoded from data
  */
+static int base32_encode(char *buf, size_t *buflen, const void *data, size_t size)
 {
 	unsigned char *udata = (unsigned char *) data;
 	int iout = 0;	/* to-be-filled output char */
@@ -196,8 +188,6 @@ base32_encode(char *buf, size_t *buflen, const void *data, size_t size)
 
 #define REV32(x) rev32[(int) (x)]
 
-static int
-base32_decode(void *buf, size_t *buflen, const char *str, size_t slen)
 /*
  * Fills *buf with max. *buflen bytes, decoded from slen chars in *str.
  * Decoding stops early when *str contains \0.
@@ -209,6 +199,8 @@ base32_decode(void *buf, size_t *buflen, const char *str, size_t slen)
  *
  * return value    : #bytes filled in buf   (excluding \0)
  */
+static int base32_decode(void *buf, size_t *buflen, const char *str,
+			 size_t slen)
 {
 	unsigned char *ubuf = (unsigned char *) buf;
 	int iout = 0;	/* to-be-filled output byte */
diff --git a/src/base64.c b/src/base64.c
index 7834731..133fcb4 100644
--- a/src/base64.c
+++ b/src/base64.c
@@ -35,9 +35,9 @@ static int reverse_init = 0;
 
 static int base64_encode(char *, size_t *, const void *, size_t);
 static int base64_decode(void *, size_t *, const char *, size_t);
-static int base64_handles_dots();
-static int base64_blksize_raw();
-static int base64_blksize_enc();
+static int base64_handles_dots(void);
+static int base64_blksize_raw(void);
+static int base64_blksize_enc(void);
 
 static struct encoder base64_encoder =
 {
@@ -50,32 +50,27 @@ static struct encoder base64_encoder =
 	base64_blksize_enc
 };
 
-struct encoder
-*get_base64_encoder()
+struct encoder *get_base64_encoder(void)
 {
 	return &base64_encoder;
 }
 
-static int
-base64_handles_dots()
+static int base64_handles_dots(void)
 {
 	return 0;
 }
 
-static int
-base64_blksize_raw()
+static int base64_blksize_raw(void)
 {
 	return BLKSIZE_RAW;
 }
 
-static int
-base64_blksize_enc()
+static int base64_blksize_enc(void)
 {
 	return BLKSIZE_ENC;
 }
 
-inline static void
-base64_reverse_init()
+inline static void base64_reverse_init(void)
 {
 	int i;
 	unsigned char c;
@@ -90,8 +85,6 @@ base64_reverse_init()
 	}
 }
 
-static int
-base64_encode(char *buf, size_t *buflen, const void *data, size_t size)
 /*
  * Fills *buf with max. *buflen characters, encoding size bytes of *data.
  *
@@ -101,6 +94,8 @@ base64_encode(char *buf, size_t *buflen, const void *data, size_t size)
  * return value    : #bytes filled in buf   (excluding \0)
  * sets *buflen to : #bytes encoded from data
  */
+static int base64_encode(char *buf, size_t *buflen, const void *data,
+			 size_t size)
 {
 	unsigned char *udata = (unsigned char *) data;
 	int iout = 0;	/* to-be-filled output char */
@@ -151,8 +146,6 @@ base64_encode(char *buf, size_t *buflen, const void *data, size_t size)
 
 #define REV64(x) rev64[(int) (x)]
 
-static int
-base64_decode(void *buf, size_t *buflen, const char *str, size_t slen)
 /*
  * Fills *buf with max. *buflen bytes, decoded from slen chars in *str.
  * Decoding stops early when *str contains \0.
@@ -164,6 +157,8 @@ base64_decode(void *buf, size_t *buflen, const char *str, size_t slen)
  *
  * return value    : #bytes filled in buf   (excluding \0)
  */
+static int base64_decode(void *buf, size_t *buflen, const char *str,
+			 size_t slen)
 {
 	unsigned char *ubuf = (unsigned char *) buf;
 	int iout = 0;	/* to-be-filled output byte */
diff --git a/src/client.c b/src/client.c
index 3930778..ea243fb 100644
--- a/src/client.c
+++ b/src/client.c
@@ -346,8 +346,7 @@ send_packet(int fd, char cmd, const char *data, const size_t datalen)
 	send_query(fd, buf);
 }
 
-static inline int
-is_sending()
+static inline int is_sending(void)
 {
 	return (outpkt.len != 0);
 }
diff --git a/src/client.h b/src/client.h
index c2493f1..41e9aa1 100644
--- a/src/client.h
+++ b/src/client.h
@@ -18,17 +18,17 @@
 #ifndef __CLIENT_H__
 #define __CLIENT_H__
 
-void client_init();
-void client_stop();
+void client_init(void);
+void client_stop(void);
 
-enum connection client_get_conn();
-const char *client_get_raw_addr();
+enum connection client_get_conn(void);
+const char *client_get_raw_addr(void);
 
 void client_set_nameserver(struct sockaddr_storage *, int);
 void client_set_topdomain(const char *cp);
 void client_set_password(const char *cp);
 int client_set_qtype(char *qtype);
-char *client_get_qtype();
+char *client_get_qtype(void);
 void client_set_downenc(char *encoding);
 void client_set_selecttimeout(int select_timeout);
 void client_set_lazymode(int lazy_mode);
diff --git a/src/common.h b/src/common.h
index 5f2c7ad..9792517 100644
--- a/src/common.h
+++ b/src/common.h
@@ -118,7 +118,7 @@ void close_dns(int);
 
 void do_chroot(char *);
 void do_setcon(char *);
-void do_detach();
+void do_detach(void);
 void do_pidfile(char *);
 
 void read_password(char*, size_t);
diff --git a/src/fw_query.h b/src/fw_query.h
index 0aa8778..7d52e4a 100644
--- a/src/fw_query.h
+++ b/src/fw_query.h
@@ -33,7 +33,7 @@ struct fw_query {
 	unsigned short id;
 };
 
-void fw_query_init();
+void fw_query_init(void);
 void fw_query_put(struct fw_query *fw_query);
 void fw_query_get(unsigned short query_id, struct fw_query **fw_query);
 
diff --git a/src/iodine.c b/src/iodine.c
index 71f73cc..64ed950 100644
--- a/src/iodine.c
+++ b/src/iodine.c
@@ -111,8 +111,7 @@ static inline void usage(void)
 	help(stderr, false);
 }
 
-static void
-version()
+static void version(void)
 {
 	fprintf(stderr, "iodine IP over DNS tunneling client\n"
 			"Git version: %s\n", GITREVISION);
@@ -120,8 +119,7 @@ version()
 	exit(0);
 }
 
-int
-main(int argc, char **argv)
+int main(int argc, char **argv)
 {
 	char *nameserv_host;
 	char *topdomain;
diff --git a/src/iodined.c b/src/iodined.c
index ed24c38..2fd0611 100644
--- a/src/iodined.c
+++ b/src/iodined.c
@@ -199,17 +199,15 @@ sigint(int sig)
 #define	LOG_NOTICE	5
 #define	LOG_INFO	6
 #define	LOG_DEBUG	7
-static void
-syslog(int a, const char *str, ...)
+
+static void syslog(int a, const char *str, ...)
 {
 	/* TODO: implement (add to event log), move to common.c */
-	;
 }
 #endif
 
 /* This will not check that user has passed login challenge */
-static int
-check_user_and_ip(int userid, struct query *q)
+static int check_user_and_ip(int userid, struct query *q)
 {
 	/* Note: duplicate in handle_raw_login() except IP-address check */
 
@@ -252,8 +250,7 @@ check_user_and_ip(int userid, struct query *q)
 }
 
 /* This checks that user has passed normal (non-raw) login challenge */
-static int
-check_authenticated_user_and_ip(int userid, struct query *q)
+static int check_authenticated_user_and_ip(int userid, struct query *q)
 {
 	int res = check_user_and_ip(userid, q);
 	if (res)
@@ -265,8 +262,7 @@ check_authenticated_user_and_ip(int userid, struct query *q)
 	return 0;
 }
 
-static void
-send_raw(int fd, char *buf, int buflen, int user, int cmd, struct query *q)
+static void send_raw(int fd, char *buf, int buflen, int user, int cmd, struct query *q)
 {
 	char packet[4096];
 	int len;
@@ -290,8 +286,7 @@ send_raw(int fd, char *buf, int buflen, int user, int cmd, struct query *q)
 }
 
 
-static void
-start_new_outpacket(int userid, char *data, int datalen)
+static void start_new_outpacket(int userid, char *data, int datalen)
 /* Copies data to .outpacket and resets all counters.
    data is expected to be compressed already. */
 {
@@ -307,8 +302,7 @@ start_new_outpacket(int userid, char *data, int datalen)
 
 #ifdef OUTPACKETQ_LEN
 
-static int
-save_to_outpacketq(int userid, char *data, int datalen)
+static int save_to_outpacketq(int userid, char *data, int datalen)
 /* Find space in outpacket-queue and store data (expected compressed already).
    Returns: 1 = okay, 0 = no space. */
 {
@@ -336,8 +330,7 @@ save_to_outpacketq(int userid, char *data, int datalen)
 	return 1;
 }
 
-static int
-get_from_outpacketq(int userid)
+static int get_from_outpacketq(int userid)
 /* Starts new outpacket from queue, if any.
    Returns: 1 = okay, 0 = no packets were waiting. */
 {
@@ -384,8 +377,7 @@ get_from_outpacketq(int userid)
    number, and of course data.)
 */
 
-static void
-save_to_dnscache(int userid, struct query *q, char *answer, int answerlen)
+static void save_to_dnscache(int userid, struct query *q, char *answer, int answerlen)
 /* Store answer in our little DNS cache. */
 {
 	int fill;
@@ -404,8 +396,7 @@ save_to_dnscache(int userid, struct query *q, char *answer, int answerlen)
 	users[userid].dnscache_lastfilled = fill;
 }
 
-static int
-answer_from_dnscache(int dns_fd, int userid, struct query *q)
+static int answer_from_dnscache(int dns_fd, int userid, struct query *q)
 /* Checks cache and sends repeated answer if we alreay saw this query recently.
    Returns: 1 = answer sent, drop this query, 0 = no answer sent, this is
    a new query. */
@@ -446,10 +437,11 @@ answer_from_dnscache(int dns_fd, int userid, struct query *q)
 
 #endif /* DNSCACHE_LEN */
 
-static inline void
-save_to_qmem(unsigned char *qmem_cmc, unsigned short *qmem_type, int qmem_len,
-	     int *qmem_lastfilled, unsigned char *cmc_to_add,
-	     unsigned short type_to_add)
+static inline void save_to_qmem(unsigned char *qmem_cmc,
+				unsigned short *qmem_type, int qmem_len,
+				int *qmem_lastfilled,
+				unsigned char *cmc_to_add,
+				unsigned short type_to_add)
 /* Remember query to check for duplicates */
 {
 	int fill;
@@ -463,8 +455,7 @@ save_to_qmem(unsigned char *qmem_cmc, unsigned short *qmem_type, int qmem_len,
 	*qmem_lastfilled = fill;
 }
 
-static inline void
-save_to_qmem_pingordata(int userid, struct query *q)
+static inline void save_to_qmem_pingordata(int userid, struct query *q)
 {
 	/* Our CMC is a bit more than the "official" CMC; we store 4 bytes
 	   just because we can, and because it may prevent some false matches.
@@ -519,10 +510,9 @@ save_to_qmem_pingordata(int userid, struct query *q)
 	}
 }
 
-static int
-answer_from_qmem(int dns_fd, struct query *q, unsigned char *qmem_cmc,
-		 unsigned short *qmem_type, int qmem_len,
-		 unsigned char *cmc_to_check)
+static int answer_from_qmem(int dns_fd, struct query *q,
+			    unsigned char *qmem_cmc, unsigned short *qmem_type,
+			    int qmem_len, unsigned char *cmc_to_check)
 /* Checks query memory and sends an (illegal) answer if this is a duplicate.
    Returns: 1 = answer sent, drop this query, 0 = no answer sent, this is
    not a duplicate. */
@@ -552,9 +542,9 @@ answer_from_qmem(int dns_fd, struct query *q, unsigned char *qmem_cmc,
 	return 0;
 }
 
-static inline int
-answer_from_qmem_data(int dns_fd, int userid, struct query *q)
 /* Quick helper function to keep handle_null_request() clean */
+static inline int answer_from_qmem_data(int dns_fd, int userid,
+					struct query *q)
 {
 	char cmc[4];
 	int i;
@@ -570,8 +560,6 @@ answer_from_qmem_data(int dns_fd, int userid, struct query *q)
 				(void *) cmc);
 }
 
-static int
-send_chunk_or_dataless(int dns_fd, int userid, struct query *q)
 /* Sends current fragment to user, or dataless packet if there is no
    current fragment available (-> normal "quiet" ping reply).
    Does not update anything, except:
@@ -581,6 +569,7 @@ send_chunk_or_dataless(int dns_fd, int userid, struct query *q)
    Returns: 1 = can call us again immediately, new packet from queue;
    0 = don't call us again for now.
 */
+static int send_chunk_or_dataless(int dns_fd, int userid, struct query *q)
 {
 	char pkt[4096];
 	int datalen = 0;
@@ -664,8 +653,7 @@ send_chunk_or_dataless(int dns_fd, int userid, struct query *q)
 	return 0;	/* don't call us again */
 }
 
-static int
-tunnel_tun(int tun_fd, struct dnsfd *dns_fds)
+static int tunnel_tun(int tun_fd, struct dnsfd *dns_fds)
 {
 	unsigned long outlen;
 	struct ip *header;
@@ -722,8 +710,8 @@ typedef enum {
 	VERSION_FULL
 } version_ack_t;
 
-static void
-send_version_response(int fd, version_ack_t ack, uint32_t payload, int userid, struct query *q)
+static void send_version_response(int fd, version_ack_t ack, uint32_t payload,
+				  int userid, struct query *q)
 {
 	char out[9];
 
@@ -748,12 +736,11 @@ send_version_response(int fd, version_ack_t ack, uint32_t payload, int userid, s
 	write_dns(fd, q, out, sizeof(out), users[userid].downenc);
 }
 
-static void
-process_downstream_ack(int userid, int down_seq, int down_frag)
 /* Process acks from downstream fragments.
    After this, .offset and .fragment are updated (if ack correct),
    or .len is set to zero when all is done.
 */
+static void process_downstream_ack(int userid, int down_seq, int down_frag)
 {
 	if (users[userid].outpacket.len <= 0)
 		/* No packet to apply acks to */
@@ -2340,16 +2327,15 @@ static void help(FILE *stream)
 	exit(0);
 }
 
-static void
-version() {
+static void version(void)
+{
 	fprintf(stderr, "iodine IP over DNS tunneling server\n"
 			"Git version: %s\n", GITREVISION);
 
 	exit(0);
 }
 
-static void
-prepare_dns_fd(int fd)
+static void prepare_dns_fd(int fd)
 {
 #ifndef WINDOWS32
 	int flag = 1;
diff --git a/src/user.c b/src/user.c
index ce1fa5a..db76e39 100644
--- a/src/user.c
+++ b/src/user.c
@@ -37,8 +37,7 @@
 struct tun_user *users;
 unsigned usercount;
 
-int
-init_users(in_addr_t my_ip, int netbits)
+int init_users(in_addr_t my_ip, int netbits)
 {
 	int i;
 	int skip = 0;
@@ -84,16 +83,14 @@ init_users(in_addr_t my_ip, int netbits)
 	return usercount;
 }
 
-const char*
-users_get_first_ip()
+const char *users_get_first_ip(void)
 {
 	struct in_addr ip;
 	ip.s_addr = users[0].tun_ip;
 	return strdup(inet_ntoa(ip));
 }
 
-int
-find_user_by_ip(uint32_t ip)
+int find_user_by_ip(uint32_t ip)
 {
 	int ret;
 	int i;
@@ -112,13 +109,12 @@ find_user_by_ip(uint32_t ip)
 	return ret;
 }
 
-int
-all_users_waiting_to_send()
 /* If this returns true, then reading from tun device is blocked.
    So only return true when all clients have at least one packet in
    the outpacket-queue, so that sending back-to-back is possible
    without going through another select loop.
 */
+int all_users_waiting_to_send(void)
 {
 	time_t now;
 	int ret;
@@ -145,8 +141,7 @@ all_users_waiting_to_send()
 	return ret;
 }
 
-int
-find_available_user()
+int find_available_user(void)
 {
 	int ret = -1;
 	int i;
@@ -166,8 +161,7 @@ find_available_user()
 	return ret;
 }
 
-void
-user_switch_codec(int userid, struct encoder *enc)
+void user_switch_codec(int userid, struct encoder *enc)
 {
 	if (userid < 0 || userid >= usercount)
 		return;
@@ -175,8 +169,7 @@ user_switch_codec(int userid, struct encoder *enc)
 	users[userid].encoder = enc;
 }
 
-void
-user_set_conn_type(int userid, enum connection c)
+void user_set_conn_type(int userid, enum connection c)
 {
 	if (userid < 0 || userid >= usercount)
 		return;
diff --git a/src/user.h b/src/user.h
index 7d2553a..c6aa523 100644
--- a/src/user.h
+++ b/src/user.h
@@ -80,10 +80,10 @@ struct tun_user {
 extern struct tun_user *users;
 
 int init_users(in_addr_t, int);
-const char* users_get_first_ip();
+const char* users_get_first_ip(void);
 int find_user_by_ip(uint32_t);
-int all_users_waiting_to_send();
-int find_available_user();
+int all_users_waiting_to_send(void);
+int find_available_user(void);
 void user_switch_codec(int userid, struct encoder *enc);
 void user_set_conn_type(int userid, enum connection c);
 
diff --git a/src/util.c b/src/util.c
index 92e5f88..d8fbd93 100644
--- a/src/util.c
+++ b/src/util.c
@@ -19,8 +19,7 @@
 #include "common.h"
 #include "util.h"
 
-char *
-get_resolvconf_addr()
+char *get_resolvconf_addr(void)
 {
 	static char addr[16];
 	char *rv;
diff --git a/src/util.h b/src/util.h
index a0ee03b..94b4554 100644
--- a/src/util.h
+++ b/src/util.h
@@ -18,7 +18,7 @@
 #ifndef __UTIL_H__
 #define __UTIL_H__
 
-char *get_resolvconf_addr();
+char *get_resolvconf_addr(void);
 void socket_setrtable(int fd, int rtable);
 
 #endif