diff --git a/sys/netinet6/frag6.c b/sys/netinet6/frag6.c
index 2dd8aaa43346..fd05c9f7eb3e 100644
--- a/sys/netinet6/frag6.c
+++ b/sys/netinet6/frag6.c
@@ -62,11 +62,11 @@ __FBSDID("$FreeBSD$");
  */
 #define IN6_IFSTAT_STRICT
 
-static void frag6_enq __P((struct ip6asfrag *, struct ip6asfrag *));
-static void frag6_deq __P((struct ip6asfrag *));
-static void frag6_insque __P((struct ip6q *, struct ip6q *));
-static void frag6_remque __P((struct ip6q *));
-static void frag6_freef __P((struct ip6q *));
+static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *);
+static void frag6_deq(struct ip6asfrag *);
+static void frag6_insque(struct ip6q *, struct ip6q *);
+static void frag6_remque(struct ip6q *);
+static void frag6_freef(struct ip6q *);
 
 static struct mtx ip6qlock;
 /*
diff --git a/sys/netinet6/icmp6.c b/sys/netinet6/icmp6.c
index c224663b6df5..ea5a646c6141 100644
--- a/sys/netinet6/icmp6.c
+++ b/sys/netinet6/icmp6.c
@@ -117,19 +117,19 @@ static int icmp6errpps_count = 0;
 static struct timeval icmp6errppslim_last;
 extern int icmp6_nodeinfo;
 
-static void icmp6_errcount __P((struct icmp6errstat *, int, int));
-static int icmp6_rip6_input __P((struct mbuf **, int));
-static int icmp6_ratelimit __P((const struct in6_addr *, const int, const int));
+static void icmp6_errcount(struct icmp6errstat *, int, int);
+static int icmp6_rip6_input(struct mbuf **, int);
+static int icmp6_ratelimit(const struct in6_addr *, const int, const int);
 static const char *icmp6_redirect_diag __P((struct in6_addr *,
 	struct in6_addr *, struct in6_addr *));
-static struct mbuf *ni6_input __P((struct mbuf *, int));
-static struct mbuf *ni6_nametodns __P((const char *, int, int));
-static int ni6_dnsmatch __P((const char *, int, const char *, int));
+static struct mbuf *ni6_input(struct mbuf *, int);
+static struct mbuf *ni6_nametodns(const char *, int, int);
+static int ni6_dnsmatch(const char *, int, const char *, int);
 static int ni6_addrs __P((struct icmp6_nodeinfo *, struct mbuf *,
 			  struct ifnet **, struct in6_addr *));
 static int ni6_store_addrs __P((struct icmp6_nodeinfo *, struct icmp6_nodeinfo *,
 				struct ifnet *, int));
-static int icmp6_notify_error __P((struct mbuf **, int, int, int));
+static int icmp6_notify_error(struct mbuf **, int, int, int);
 
 
 void
@@ -885,7 +885,7 @@ icmp6_notify_error(struct mbuf **mp, int off, int icmp6len, int code)
 
 	/* Detect the upper level protocol */
 	{
-		void (*ctlfunc) __P((int, struct sockaddr *, void *));
+		void (*ctlfunc)(int, struct sockaddr *, void *);
 		u_int8_t nxt = eip6->ip6_nxt;
 		int eoff = off + sizeof(struct icmp6_hdr) +
 		    sizeof(struct ip6_hdr);
@@ -1072,7 +1072,7 @@ icmp6_notify_error(struct mbuf **mp, int off, int icmp6len, int code)
 			icmp6_mtudisc_update(&ip6cp, 1);	/*XXX*/
 		}
 
-		ctlfunc = (void (*) __P((int, struct sockaddr *, void *)))
+		ctlfunc = (void (*)(int, struct sockaddr *, void *))
 		    (inet6sw[ip6_protox[nxt]].pr_ctlinput);
 		if (ctlfunc) {
 			(void) (*ctlfunc)(code, (struct sockaddr *)&icmp6dst,
diff --git a/sys/netinet6/in6.c b/sys/netinet6/in6.c
index f66ddb4f8f7a..450b13013e88 100644
--- a/sys/netinet6/in6.c
+++ b/sys/netinet6/in6.c
@@ -127,7 +127,7 @@ static int in6_lifaddr_ioctl __P((struct socket *, u_long, caddr_t,
 	struct ifnet *, struct thread *));
 static int in6_ifinit __P((struct ifnet *, struct in6_ifaddr *,
 	struct sockaddr_in6 *, int));
-static void in6_unlink_ifa __P((struct in6_ifaddr *, struct ifnet *));
+static void in6_unlink_ifa(struct in6_ifaddr *, struct ifnet *);
 
 struct in6_multihead in6_multihead;	/* XXX BSS initialization */
 int	(*faithprefix_p)(struct in6_addr *);
diff --git a/sys/netinet6/in6_ifattach.c b/sys/netinet6/in6_ifattach.c
index 297c0cd4af8e..6962deb46416 100644
--- a/sys/netinet6/in6_ifattach.c
+++ b/sys/netinet6/in6_ifattach.c
@@ -73,12 +73,12 @@ struct callout in6_tmpaddrtimer_ch;
 extern struct inpcbinfo udbinfo;
 extern struct inpcbinfo ripcbinfo;
 
-static int get_rand_ifid __P((struct ifnet *, struct in6_addr *));
-static int generate_tmp_ifid __P((u_int8_t *, const u_int8_t *, u_int8_t *));
-static int get_ifid __P((struct ifnet *, struct ifnet *, struct in6_addr *));
-static int in6_ifattach_linklocal __P((struct ifnet *, struct ifnet *));
-static int in6_ifattach_loopback __P((struct ifnet *));
-static void in6_purgemaddrs __P((struct ifnet *));
+static int get_rand_ifid(struct ifnet *, struct in6_addr *);
+static int generate_tmp_ifid(u_int8_t *, const u_int8_t *, u_int8_t *);
+static int get_ifid(struct ifnet *, struct ifnet *, struct in6_addr *);
+static int in6_ifattach_linklocal(struct ifnet *, struct ifnet *);
+static int in6_ifattach_loopback(struct ifnet *);
+static void in6_purgemaddrs(struct ifnet *);
 
 #define EUI64_GBIT	0x01
 #define EUI64_UBIT	0x02
diff --git a/sys/netinet6/in6_pcb.c b/sys/netinet6/in6_pcb.c
index cbb27d8b767a..2419b89f36cf 100644
--- a/sys/netinet6/in6_pcb.c
+++ b/sys/netinet6/in6_pcb.c
@@ -571,7 +571,7 @@ void
 in6_pcbnotify(struct inpcbinfo *pcbinfo, struct sockaddr *dst,
     u_int fport_arg, const struct sockaddr *src, u_int lport_arg,
     int cmd, void *cmdarg,
-    struct inpcb *(*notify) __P((struct inpcb *, int)))
+    struct inpcb *(*notify)(struct inpcb *, int))
 {
 	struct inpcbhead *head;
 	struct inpcb *inp, *ninp;
diff --git a/sys/netinet6/in6_proto.c b/sys/netinet6/in6_proto.c
index 6a39d645ed13..7e6a75ec7ac1 100644
--- a/sys/netinet6/in6_proto.c
+++ b/sys/netinet6/in6_proto.c
@@ -339,7 +339,7 @@ struct ip6protosw inet6sw[] = {
 },
 };
 
-extern int in6_inithead __P((void **, int));
+extern int in6_inithead(void **, int);
 
 struct domain inet6domain = {
 	.dom_family =		AF_INET6,
diff --git a/sys/netinet6/in6_rmx.c b/sys/netinet6/in6_rmx.c
index 59e109e81784..ea4c7ff322ea 100644
--- a/sys/netinet6/in6_rmx.c
+++ b/sys/netinet6/in6_rmx.c
@@ -103,7 +103,7 @@ __FBSDID("$FreeBSD$");
 #include <netinet/tcp_timer.h>
 #include <netinet/tcp_var.h>
 
-extern int	in6_inithead __P((void **head, int off));
+extern int	in6_inithead(void **head, int off);
 
 #define RTPRF_OURS		RTF_PROTO3	/* set on routes we manage */
 
diff --git a/sys/netinet6/in6_src.c b/sys/netinet6/in6_src.c
index 76a412a9258e..3093f6f8427e 100644
--- a/sys/netinet6/in6_src.c
+++ b/sys/netinet6/in6_src.c
@@ -121,15 +121,15 @@ static int selectroute __P((struct sockaddr_in6 *, struct ip6_pktopts *,
 static int in6_selectif __P((struct sockaddr_in6 *, struct ip6_pktopts *,
 	struct ip6_moptions *, struct route_in6 *ro, struct ifnet **));
 
-static struct in6_addrpolicy *lookup_addrsel_policy __P((struct sockaddr_in6 *));
+static struct in6_addrpolicy *lookup_addrsel_policy(struct sockaddr_in6 *);
 
-static void init_policy_queue __P((void));
-static int add_addrsel_policyent __P((struct in6_addrpolicy *));
-static int delete_addrsel_policyent __P((struct in6_addrpolicy *));
+static void init_policy_queue(void);
+static int add_addrsel_policyent(struct in6_addrpolicy *);
+static int delete_addrsel_policyent(struct in6_addrpolicy *);
 static int walk_addrsel_policy __P((int (*)(struct in6_addrpolicy *, void *),
 				    void *));
-static int dump_addrsel_policyent __P((struct in6_addrpolicy *, void *));
-static struct in6_addrpolicy *match_addrsel_policy __P((struct sockaddr_in6 *));
+static int dump_addrsel_policyent(struct in6_addrpolicy *, void *);
+static struct in6_addrpolicy *match_addrsel_policy(struct sockaddr_in6 *);
 
 /*
  * Return an IPv6 address, which is the most appropriate for a given
@@ -1010,7 +1010,7 @@ delete_addrsel_policyent(struct in6_addrpolicy *key)
 }
 
 static int
-walk_addrsel_policy(int (*callback) __P((struct in6_addrpolicy *, void *)),
+walk_addrsel_policy(int (*callback)(struct in6_addrpolicy *, void *),
     void *w)
 {
 	struct addrsel_policyent *pol;
diff --git a/sys/netinet6/ip6_input.c b/sys/netinet6/ip6_input.c
index acf1d2d92d6d..c15b9621586f 100644
--- a/sys/netinet6/ip6_input.c
+++ b/sys/netinet6/ip6_input.c
@@ -130,11 +130,11 @@ struct pfil_head inet6_pfil_hook;
 
 struct ip6stat ip6stat;
 
-static void ip6_init2 __P((void *));
-static struct ip6aux *ip6_setdstifaddr __P((struct mbuf *, struct in6_ifaddr *));
-static int ip6_hopopts_input __P((u_int32_t *, u_int32_t *, struct mbuf **, int *));
+static void ip6_init2(void *);
+static struct ip6aux *ip6_setdstifaddr(struct mbuf *, struct in6_ifaddr *);
+static int ip6_hopopts_input(u_int32_t *, u_int32_t *, struct mbuf **, int *);
 #ifdef PULLDOWN_TEST
-static struct mbuf *ip6_pullexthdr __P((struct mbuf *, size_t, int));
+static struct mbuf *ip6_pullexthdr(struct mbuf *, size_t, int);
 #endif
 
 /*
diff --git a/sys/netinet6/ip6_mroute.c b/sys/netinet6/ip6_mroute.c
index a14882f6955f..1465a901590d 100644
--- a/sys/netinet6/ip6_mroute.c
+++ b/sys/netinet6/ip6_mroute.c
@@ -125,10 +125,10 @@ static MALLOC_DEFINE(M_MRTABLE6, "mf6c", "multicast forwarding cache entry");
 /* XXX: this is a very common idiom; move to <sys/mbuf.h> ? */
 #define M_HASCL(m) ((m)->m_flags & M_EXT)
 
-static int ip6_mdq __P((struct mbuf *, struct ifnet *, struct mf6c *));
-static void phyint_send __P((struct ip6_hdr *, struct mif6 *, struct mbuf *));
+static int ip6_mdq(struct mbuf *, struct ifnet *, struct mf6c *);
+static void phyint_send(struct ip6_hdr *, struct mif6 *, struct mbuf *);
 
-static int set_pim6 __P((int *));
+static int set_pim6(int *);
 static int socket_send __P((struct socket *, struct mbuf *,
 	    struct sockaddr_in6 *));
 static int register_send __P((struct ip6_hdr *, struct mif6 *,
@@ -185,7 +185,7 @@ static u_int mrt6debug = 0;		/* debug level */
 #define DEBUG_PIM	0x40
 #endif
 
-static void	expire_upcalls __P((void *));
+static void	expire_upcalls(void *);
 #define	EXPIRE_TIMEOUT	(hz / 4)	/* 4x / second */
 #define	UPCALL_EXPIRE	6		/* number of timeouts */
 
@@ -285,13 +285,13 @@ static u_long upcall_data[UPCALL_MAX + 1];
 static void collate();
 #endif /* UPCALL_TIMING */
 
-static int get_sg_cnt __P((struct sioc_sg_req6 *));
-static int get_mif6_cnt __P((struct sioc_mif_req6 *));
-static int ip6_mrouter_init __P((struct socket *, int, int));
-static int add_m6if __P((struct mif6ctl *));
-static int del_m6if __P((mifi_t *));
-static int add_m6fc __P((struct mf6cctl *));
-static int del_m6fc __P((struct mf6cctl *));
+static int get_sg_cnt(struct sioc_sg_req6 *);
+static int get_mif6_cnt(struct sioc_mif_req6 *);
+static int ip6_mrouter_init(struct socket *, int, int);
+static int add_m6if(struct mif6ctl *);
+static int del_m6if(mifi_t *);
+static int add_m6fc(struct mf6cctl *);
+static int del_m6fc(struct mf6cctl *);
 
 static struct callout expire_upcalls_ch;
 
diff --git a/sys/netinet6/ip6_output.c b/sys/netinet6/ip6_output.c
index 303028c8ef04..a79363ebded3 100644
--- a/sys/netinet6/ip6_output.c
+++ b/sys/netinet6/ip6_output.c
@@ -117,20 +117,20 @@ static int ip6_pcbopt __P((int, u_char *, int, struct ip6_pktopts **,
 			   int, int));
 static int ip6_pcbopts __P((struct ip6_pktopts **, struct mbuf *,
 	struct socket *, struct sockopt *));
-static int ip6_getpcbopt __P((struct ip6_pktopts *, int, struct sockopt *));
+static int ip6_getpcbopt(struct ip6_pktopts *, int, struct sockopt *);
 static int ip6_setpktopt __P((int, u_char *, int, struct ip6_pktopts *, int,
 	int, int, int));
 
-static int ip6_setmoptions __P((int, struct ip6_moptions **, struct mbuf *));
-static int ip6_getmoptions __P((int, struct ip6_moptions *, struct mbuf **));
-static int ip6_copyexthdr __P((struct mbuf **, caddr_t, int));
+static int ip6_setmoptions(int, struct ip6_moptions **, struct mbuf *);
+static int ip6_getmoptions(int, struct ip6_moptions *, struct mbuf **);
+static int ip6_copyexthdr(struct mbuf **, caddr_t, int);
 static int ip6_insertfraghdr __P((struct mbuf *, struct mbuf *, int,
 	struct ip6_frag **));
-static int ip6_insert_jumboopt __P((struct ip6_exthdrs *, u_int32_t));
-static int ip6_splithdr __P((struct mbuf *, struct ip6_exthdrs *));
+static int ip6_insert_jumboopt(struct ip6_exthdrs *, u_int32_t);
+static int ip6_splithdr(struct mbuf *, struct ip6_exthdrs *);
 static int ip6_getpmtu __P((struct route_in6 *, struct route_in6 *,
 	struct ifnet *, struct in6_addr *, u_long *, int *));
-static int copypktopts __P((struct ip6_pktopts *, struct ip6_pktopts *, int));
+static int copypktopts(struct ip6_pktopts *, struct ip6_pktopts *, int);
 
 
 /*
diff --git a/sys/netinet6/mld6.c b/sys/netinet6/mld6.c
index e48a4970f489..b8f54bf98753 100644
--- a/sys/netinet6/mld6.c
+++ b/sys/netinet6/mld6.c
@@ -148,7 +148,7 @@ mld_starttimer(struct in6_multi *in6m)
 
 	/* start or restart the timer */
 	callout_reset(in6m->in6m_timer_ch, in6m->in6m_timer,
-	    (void (*) __P((void *)))mld_timeo, in6m);
+	    (void (*)(void *))mld_timeo, in6m);
 }
 
 static void
diff --git a/sys/netinet6/nd6.c b/sys/netinet6/nd6.c
index 02140bc858c3..5964570aeb42 100644
--- a/sys/netinet6/nd6.c
+++ b/sys/netinet6/nd6.c
@@ -110,12 +110,12 @@ static struct sockaddr_in6 all1_sa;
 
 static int nd6_is_new_addr_neighbor __P((struct sockaddr_in6 *,
 	struct ifnet *));
-static void nd6_setmtu0 __P((struct ifnet *, struct nd_ifinfo *));
-static void nd6_slowtimo __P((void *));
-static int regen_tmpaddr __P((struct in6_ifaddr *));
-static struct llinfo_nd6 *nd6_free __P((struct rtentry *, int));
-static void nd6_llinfo_timer __P((void *));
-static void clear_llinfo_pqueue __P((struct llinfo_nd6 *));
+static void nd6_setmtu0(struct ifnet *, struct nd_ifinfo *);
+static void nd6_slowtimo(void *);
+static int regen_tmpaddr(struct in6_ifaddr *);
+static struct llinfo_nd6 *nd6_free(struct rtentry *, int);
+static void nd6_llinfo_timer(void *);
+static void clear_llinfo_pqueue(struct llinfo_nd6 *);
 
 struct callout nd6_slowtimo_ch;
 struct callout nd6_timer_ch;
diff --git a/sys/netinet6/nd6_nbr.c b/sys/netinet6/nd6_nbr.c
index 91a883a5905a..fce616ba527a 100644
--- a/sys/netinet6/nd6_nbr.c
+++ b/sys/netinet6/nd6_nbr.c
@@ -73,13 +73,13 @@ __FBSDID("$FreeBSD$");
 #define SDL(s) ((struct sockaddr_dl *)s)
 
 struct dadq;
-static struct dadq *nd6_dad_find __P((struct ifaddr *));
-static void nd6_dad_starttimer __P((struct dadq *, int));
-static void nd6_dad_stoptimer __P((struct dadq *));
-static void nd6_dad_timer __P((struct ifaddr *));
-static void nd6_dad_ns_output __P((struct dadq *, struct ifaddr *));
-static void nd6_dad_ns_input __P((struct ifaddr *));
-static void nd6_dad_na_input __P((struct ifaddr *));
+static struct dadq *nd6_dad_find(struct ifaddr *);
+static void nd6_dad_starttimer(struct dadq *, int);
+static void nd6_dad_stoptimer(struct dadq *);
+static void nd6_dad_timer(struct ifaddr *);
+static void nd6_dad_ns_output(struct dadq *, struct ifaddr *);
+static void nd6_dad_ns_input(struct ifaddr *);
+static void nd6_dad_na_input(struct ifaddr *);
 
 static int dad_ignore_ns = 0;	/* ignore NS in DAD - specwise incorrect*/
 static int dad_maxtry = 15;	/* max # of *tries* to transmit DAD packet */
@@ -1079,7 +1079,7 @@ nd6_dad_starttimer(struct dadq *dp, int ticks)
 {
 
 	callout_reset(&dp->dad_timer_ch, ticks,
-	    (void (*) __P((void *)))nd6_dad_timer, (void *)dp->dad_ifa);
+	    (void (*)(void *))nd6_dad_timer, (void *)dp->dad_ifa);
 }
 
 static void
diff --git a/sys/netinet6/nd6_rtr.c b/sys/netinet6/nd6_rtr.c
index 831f81029c8d..08f9a8311ad7 100644
--- a/sys/netinet6/nd6_rtr.c
+++ b/sys/netinet6/nd6_rtr.c
@@ -64,25 +64,25 @@ __FBSDID("$FreeBSD$");
 
 #define SDL(s)	((struct sockaddr_dl *)s)
 
-static int rtpref __P((struct nd_defrouter *));
-static struct nd_defrouter *defrtrlist_update __P((struct nd_defrouter *));
+static int rtpref(struct nd_defrouter *);
+static struct nd_defrouter *defrtrlist_update(struct nd_defrouter *);
 static int prelist_update __P((struct nd_prefixctl *, struct nd_defrouter *,
     struct mbuf *, int));
-static struct in6_ifaddr *in6_ifadd __P((struct nd_prefixctl *,	int));
+static struct in6_ifaddr *in6_ifadd(struct nd_prefixctl *,	int);
 static struct nd_pfxrouter *pfxrtr_lookup __P((struct nd_prefix *,
 	struct nd_defrouter *));
-static void pfxrtr_add __P((struct nd_prefix *, struct nd_defrouter *));
-static void pfxrtr_del __P((struct nd_pfxrouter *));
+static void pfxrtr_add(struct nd_prefix *, struct nd_defrouter *);
+static void pfxrtr_del(struct nd_pfxrouter *);
 static struct nd_pfxrouter *find_pfxlist_reachable_router
-	__P((struct nd_prefix *));
-static void defrouter_delreq __P((struct nd_defrouter *));
-static void nd6_rtmsg __P((int, struct rtentry *));
+(struct nd_prefix *);
+static void defrouter_delreq(struct nd_defrouter *);
+static void nd6_rtmsg(int, struct rtentry *);
 
-static int in6_init_prefix_ltimes __P((struct nd_prefix *));
+static int in6_init_prefix_ltimes(struct nd_prefix *);
 static void in6_init_address_ltimes __P((struct nd_prefix *,
 	struct in6_addrlifetime *));
 
-static int rt6_deleteroute __P((struct radix_node *, void *));
+static int rt6_deleteroute(struct radix_node *, void *);
 
 extern int nd6_recalc_reachtm_interval;
 
diff --git a/sys/netinet6/raw_ip6.c b/sys/netinet6/raw_ip6.c
index 9353a7361ef9..e8b5aa2a58dc 100644
--- a/sys/netinet6/raw_ip6.c
+++ b/sys/netinet6/raw_ip6.c
@@ -265,7 +265,7 @@ rip6_ctlinput(int cmd, struct sockaddr *sa, void *d)
 	struct ip6ctlparam *ip6cp = NULL;
 	const struct sockaddr_in6 *sa6_src = NULL;
 	void *cmdarg;
-	struct inpcb *(*notify) __P((struct inpcb *, int)) = in6_rtchange;
+	struct inpcb *(*notify)(struct inpcb *, int) = in6_rtchange;
 
 	if (sa->sa_family != AF_INET6 ||
 	    sa->sa_len != sizeof(struct sockaddr_in6))
diff --git a/sys/netinet6/udp6_usrreq.c b/sys/netinet6/udp6_usrreq.c
index 96b72b21981a..f9f329764ca5 100644
--- a/sys/netinet6/udp6_usrreq.c
+++ b/sys/netinet6/udp6_usrreq.c
@@ -367,7 +367,7 @@ udp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
 	struct ip6ctlparam *ip6cp = NULL;
 	const struct sockaddr_in6 *sa6_src = NULL;
 	void *cmdarg;
-	struct inpcb *(*notify) __P((struct inpcb *, int)) = udp_notify;
+	struct inpcb *(*notify)(struct inpcb *, int) = udp_notify;
 	struct udp_portonly {
 		u_int16_t uh_sport;
 		u_int16_t uh_dport;