netdev - [PATCH] dnet: fix strict aliasing warnings

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Date:	Wed,  9 Jun 2010 20:52:41 -0400
From:	Mike Frysinger <vapier@...too.org>
To:	stephen.hemminger@...tta.com, netdev@...r.kernel.org
Subject: [PATCH] dnet: fix strict aliasing warnings

Recent gcc doesn't like it when you cast char pointers to uint16_t
pointers and then dereference it.  So use memcpy() instead and let
gcc take care of optimizing things away (when appropriate).  This
should also fix alignment issues on arches where gcc packs the char
pointer tighter than 16bits.

Signed-off-by: Mike Frysinger <vapier@...too.org>
---
 lib/dnet_ntop.c |    8 ++++++--
 lib/dnet_pton.c |    5 ++++-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/lib/dnet_ntop.c b/lib/dnet_ntop.c
index 9500df8..507a7eb 100644
--- a/lib/dnet_ntop.c
+++ b/lib/dnet_ntop.c
@@ -1,4 +1,5 @@
 #include <errno.h>
+#include <string.h>
 #include <sys/types.h>
 #include <netinet/in.h>
 
@@ -35,11 +36,14 @@ static __inline__ int do_digit(char *str, u_int16_t *addr, u_int16_t scale, size
 
 static const char *dnet_ntop1(const struct dn_naddr *dna, char *str, size_t len)
 {
-	u_int16_t addr = dn_ntohs(*(u_int16_t *)dna->a_addr);
-	u_int16_t area = addr >> 10;
+	u_int16_t addr, area;
 	size_t pos = 0;
 	int started = 0;
 
+	memcpy(&addr, dna->a_addr, sizeof(addr));
+	addr = dn_ntohs(addr);
+	area = addr >> 10;
+
 	if (dna->a_len != 2)
 		return NULL;
 
diff --git a/lib/dnet_pton.c b/lib/dnet_pton.c
index bd7727a..7385756 100644
--- a/lib/dnet_pton.c
+++ b/lib/dnet_pton.c
@@ -1,4 +1,5 @@
 #include <errno.h>
+#include <string.h>
 #include <sys/types.h>
 #include <netinet/in.h>
 
@@ -37,6 +38,7 @@ static int dnet_num(const char *src, u_int16_t * dst)
 
 static int dnet_pton1(const char *src, struct dn_naddr *dna)
 {
+	u_int16_t addr;
 	u_int16_t area = 0;
 	u_int16_t node = 0;
 	int pos;
@@ -48,7 +50,8 @@ static int dnet_pton1(const char *src, struct dn_naddr *dna)
 	if ((pos == 0) || (node > 1023))
 		return 0;
 	dna->a_len = 2;
-	*(u_int16_t *)dna->a_addr = dn_htons((area << 10) | node);
+	addr = dn_htons((area << 10) | node);
+	memcpy(dna->a_addr, &addr, sizeof(addr));
 
 	return 1;
 }
-- 
1.7.1

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