netinet*: variable cleanup

In preparation for another change factor out various variable cleanups.
These mainly include:
(1) do not assign values to variables during declaration:  this makes
    the code more readable and does allow for better grouping of
    variable declarations,
(2) do not assign values to variables before need; e.g., if a variable
    is only used in the 2nd half of a function and we have multiple
    return paths before that, then do not set it before it is needed, and
(3) try to avoid assigning the same value multiple times.

MFC after:	3 weeks
Sponsored by:	Netflix

1 files changed, 53 insertions, 42 deletions

diff --git a/sys/netinet6/nd6_nbr.c b/sys/netinet6/nd6_nbr.c
index af6be371e38a..e91a1435332f 100644
--- a/sys/netinet6/nd6_nbr.c
+++ b/sys/netinet6/nd6_nbr.c
@@ -121,30 +121,33 @@ VNET_DEFINE_STATIC(int, dad_maxtry) = 15;	/* max # of *tries* to
 void
 nd6_ns_input(struct mbuf *m, int off, int icmp6len)
 {
-	struct ifnet *ifp = m->m_pkthdr.rcvif;
-	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
+	struct ifnet *ifp;
+	struct ip6_hdr *ip6;
 	struct nd_neighbor_solicit *nd_ns;
-	struct in6_addr saddr6 = ip6->ip6_src;
-	struct in6_addr daddr6 = ip6->ip6_dst;
-	struct in6_addr taddr6;
-	struct in6_addr myaddr6;
-	char *lladdr = NULL;
-	struct ifaddr *ifa = NULL;
-	int lladdrlen = 0;
-	int anycast = 0, proxy = 0, tentative = 0;
-	int tlladdr;
-	int rflag;
-	union nd_opts ndopts;
+	struct in6_addr daddr6, myaddr6, saddr6, taddr6;
+	struct ifaddr *ifa;
 	struct sockaddr_dl proxydl;
+	union nd_opts ndopts;
 	char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
+	char *lladdr;
+	int anycast, lladdrlen, proxy, rflag, tentative, tlladdr;
+
+	ifa = NULL;
 
 	/* RFC 6980: Nodes MUST silently ignore fragments */
 	if(m->m_flags & M_FRAGMENTED)
 		goto freeit;
 
-	rflag = (V_ip6_forwarding) ? ND_NA_FLAG_ROUTER : 0;
-	if (ND_IFINFO(ifp)->flags & ND6_IFF_ACCEPT_RTADV && V_ip6_norbit_raif)
-		rflag = 0;
+	ifp = m->m_pkthdr.rcvif;
+	ip6 = mtod(m, struct ip6_hdr *);
+	if (ip6->ip6_hlim != 255) {
+		nd6log((LOG_ERR,
+		    "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
+		    ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
+		    ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
+		goto bads;
+	}
+
 #ifndef PULLDOWN_TEST
 	IP6_EXTHDR_CHECK(m, off, icmp6len,);
 	nd_ns = (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
@@ -156,17 +159,16 @@ nd6_ns_input(struct mbuf *m, int off, int icmp6len)
 	}
 #endif
 	ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
+
+	saddr6 = ip6->ip6_src;
+	daddr6 = ip6->ip6_dst;
 	taddr6 = nd_ns->nd_ns_target;
 	if (in6_setscope(&taddr6, ifp, NULL) != 0)
 		goto bad;
 
-	if (ip6->ip6_hlim != 255) {
-		nd6log((LOG_ERR,
-		    "nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
-		    ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
-		    ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
-		goto bad;
-	}
+	rflag = (V_ip6_forwarding) ? ND_NA_FLAG_ROUTER : 0;
+	if (ND_IFINFO(ifp)->flags & ND6_IFF_ACCEPT_RTADV && V_ip6_norbit_raif)
+		rflag = 0;
 
 	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
 		/* dst has to be a solicited node multicast address. */
@@ -215,6 +217,8 @@ nd6_ns_input(struct mbuf *m, int off, int icmp6len)
 		goto freeit;
 	}
 
+	lladdr = NULL;
+	lladdrlen = 0;
 	if (ndopts.nd_opts_src_lladdr) {
 		lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
 		lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
@@ -254,6 +258,7 @@ nd6_ns_input(struct mbuf *m, int off, int icmp6len)
 		ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
 
 	/* (2) check. */
+	proxy = 0;
 	if (ifa == NULL) {
 		struct sockaddr_dl rt_gateway;
 		struct rt_addrinfo info;
@@ -380,6 +385,7 @@ nd6_ns_input(struct mbuf *m, int off, int icmp6len)
 		ip6_sprintf(ip6bufs, &daddr6)));
 	nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n",
 		ip6_sprintf(ip6bufs, &taddr6)));
+ bads:
 	ICMP6STAT_INC(icp6s_badns);
 	if (ifa != NULL)
 		ifa_free(ifa);
@@ -614,34 +620,34 @@ nd6_ns_output(struct ifnet *ifp, const struct in6_addr *saddr6,
 void
 nd6_na_input(struct mbuf *m, int off, int icmp6len)
 {
-	struct ifnet *ifp = m->m_pkthdr.rcvif;
-	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
-	struct nd_neighbor_advert *nd_na;
-	struct in6_addr daddr6 = ip6->ip6_dst;
-	struct in6_addr taddr6;
-	int flags;
-	int is_router;
-	int is_solicited;
-	int is_override;
-	char *lladdr = NULL;
-	int lladdrlen = 0;
-	int checklink = 0;
+	struct ifnet *ifp;
+	struct ip6_hdr *ip6;
 	struct ifaddr *ifa;
-	struct llentry *ln = NULL;
-	union nd_opts ndopts;
-	struct mbuf *chain = NULL;
+	struct llentry *ln;
+	struct mbuf *chain;
+	struct nd_neighbor_advert *nd_na;
+	struct in6_addr daddr6, taddr6;
 	struct sockaddr_in6 sin6;
+	union nd_opts ndopts;
 	u_char linkhdr[LLE_MAX_LINKHDR];
-	size_t linkhdrsize;
-	int lladdr_off;
 	char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
+	char *lladdr;
+	size_t linkhdrsize;
+	int flags, is_override, is_router, is_solicited;
+	int lladdr_off, lladdrlen, checklink;
 
 	NET_EPOCH_ASSERT();
 
+	chain = NULL;
+	ln = NULL;
+	checklink = 0;
+
 	/* RFC 6980: Nodes MUST silently ignore fragments */
 	if(m->m_flags & M_FRAGMENTED)
 		goto freeit;
 
+	ifp = m->m_pkthdr.rcvif;
+	ip6 = mtod(m, struct ip6_hdr *);
 	if (ip6->ip6_hlim != 255) {
 		nd6log((LOG_ERR,
 		    "nd6_na_input: invalid hlim (%d) from %s to %s on %s\n",
@@ -665,7 +671,6 @@ nd6_na_input(struct mbuf *m, int off, int icmp6len)
 	is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
 	is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
 	is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
-	memset(&sin6, 0, sizeof(sin6));
 
 	taddr6 = nd_na->nd_na_target;
 	if (in6_setscope(&taddr6, ifp, NULL))
@@ -677,6 +682,8 @@ nd6_na_input(struct mbuf *m, int off, int icmp6len)
 		    ip6_sprintf(ip6bufs, &taddr6)));
 		goto bad;
 	}
+
+	daddr6 = ip6->ip6_dst;
 	if (IN6_IS_ADDR_MULTICAST(&daddr6))
 		if (is_solicited) {
 			nd6log((LOG_ERR,
@@ -693,6 +700,8 @@ nd6_na_input(struct mbuf *m, int off, int icmp6len)
 		goto freeit;
 	}
 
+	lladdr = NULL;
+	lladdrlen = 0;
 	if (ndopts.nd_opts_tgt_lladdr) {
 		lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
 		lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
@@ -888,8 +897,10 @@ nd6_na_input(struct mbuf *m, int off, int icmp6len)
 	 *  rt->rt_flags &= ~RTF_REJECT;
 	 */
 	ln->la_asked = 0;
-	if (ln->la_hold != NULL)
+	if (ln->la_hold != NULL) {
+		memset(&sin6, 0, sizeof(sin6));
 		nd6_grab_holdchain(ln, &chain, &sin6);
+	}
  freeit:
 	if (ln != NULL)
 		LLE_WUNLOCK(ln);