diff --git a/sbin/ipf/common/genmask.c b/sbin/ipf/common/genmask.c
--- a/sbin/ipf/common/genmask.c
+++ b/sbin/ipf/common/genmask.c
@@ -9,10 +9,8 @@
 #include "ipf.h"
 
 
-int genmask(family, msk, mskp)
-	int family;
-	char *msk;
-	i6addr_t *mskp;
+int
+genmask(int family, char *msk, i6addr_t *mskp)
 {
 	char *endptr = 0L;
 	u_32_t addr;
diff --git a/sbin/ipf/common/lexer.c b/sbin/ipf/common/lexer.c
--- a/sbin/ipf/common/lexer.c
+++ b/sbin/ipf/common/lexer.c
@@ -603,8 +603,7 @@
 }
 
 
-static wordtab_t *yyfindkey(key)
-	char *key;
+static wordtab_t *yyfindkey(char *key)
 {
 	wordtab_t *w;
 
diff --git a/sbin/ipf/ipf/bpf_filter.c b/sbin/ipf/ipf/bpf_filter.c
--- a/sbin/ipf/ipf/bpf_filter.c
+++ b/sbin/ipf/ipf/bpf_filter.c
@@ -117,9 +117,7 @@
 }
 
 static int
-m_xword(m, k, err)
-	register mb_t *m;
-	register int k, *err;
+m_xword(mb_t *m, int k, int *err)
 {
 	register int len;
 	register u_char *cp, *np;
@@ -153,9 +151,7 @@
 }
 
 static int
-m_xhalf(m, k, err)
-	register mb_t *m;
-	register int k, *err;
+m_xhalf(mb_t *m, int k, int *err)
 {
 	register int len;
 	register u_char *cp;
@@ -185,11 +181,7 @@
  * in all other cases, p is a pointer to a buffer and buflen is its size.
  */
 u_int
-bpf_filter(pc, p, wirelen, buflen)
-	register struct bpf_insn *pc;
-	register u_char *p;
-	u_int wirelen;
-	register u_int buflen;
+bpf_filter(struct bpf_insn *pc, u_char *p, u_int wirelen, u_int buflen)
 {
 	register u_int32 A, X;
 	register int k;
@@ -478,9 +470,7 @@
  * Otherwise, a bogus program could easily crash the system.
  */
 int
-bpf_validate(f, len)
-	struct bpf_insn *f;
-	int len;
+bpf_validate(struct bpf_insn *f, int len)
 {
 	u_int i, from;
 	const struct bpf_insn *p;
diff --git a/sbin/ipf/ipfstat/ipfstat.c b/sbin/ipf/ipfstat/ipfstat.c
--- a/sbin/ipf/ipfstat/ipfstat.c
+++ b/sbin/ipf/ipfstat/ipfstat.c
@@ -162,8 +162,7 @@
 #endif
 
 
-static void usage(name)
-	char *name;
+static void usage(char *name)
 {
 #ifdef  USE_INET6
 	fprintf(stderr, "Usage: %s [-46aAdfghIilnoRsv]\n", name);
diff --git a/sbin/ipf/ipmon/ipmon.c b/sbin/ipf/ipmon/ipmon.c
--- a/sbin/ipf/ipmon/ipmon.c
+++ b/sbin/ipf/ipmon/ipmon.c
@@ -470,10 +470,7 @@
 
 
 char *
-portlocalname(res, proto, port)
-	int res;
-	char *proto;
-	u_int port;
+portlocalname(int res, char *proto, u_int port)
 {
 	static char pname[8];
 	char *s;
diff --git a/sbin/ipf/libipf/mutex_emul.c b/sbin/ipf/libipf/mutex_emul.c
--- a/sbin/ipf/libipf/mutex_emul.c
+++ b/sbin/ipf/libipf/mutex_emul.c
@@ -85,10 +85,7 @@
 
 
 void
-eMmutex_destroy(mtx, file, line)
-	eMmutex_t *mtx;
-	char *file;
-	int line;
+eMmutex_destroy(eMmutex_t *mtx, char *file, int line)
 {
 	if (mutex_debug & 1)
 		fprintf(mutex_file,
diff --git a/sbin/ipf/libipf/poolio.c b/sbin/ipf/libipf/poolio.c
--- a/sbin/ipf/libipf/poolio.c
+++ b/sbin/ipf/libipf/poolio.c
@@ -28,10 +28,7 @@
 }
 
 int
-pool_ioctl(iocfunc, cmd, ptr)
-	ioctlfunc_t iocfunc;
-	ioctlcmd_t cmd;
-	void *ptr;
+pool_ioctl(ioctlfunc_t iocfunc, ioctlcmd_t cmd, void *ptr)
 {
 	return (*iocfunc)(poolfd, cmd, ptr);
 }
diff --git a/sbin/ipf/libipf/var.c b/sbin/ipf/libipf/var.c
--- a/sbin/ipf/libipf/var.c
+++ b/sbin/ipf/libipf/var.c
@@ -24,8 +24,7 @@
 static char *expand_string(char *, int);
 
 
-static variable_t *find_var(name)
-	char *name;
+static variable_t *find_var(char *name)
 {
 	variable_t *v;