[PATCH 09/22] tcp, udp, util: Fixes for bitmap handling on big-endian, casts

[Stefano Brivio <sbrivio@redhat.com>]

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Bitmap manipulating functions would otherwise refer to inconsistent
sets of bits on big-endian architectures. While at it, fix up a
couple of casts.

Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>
---
 passt.h |  3 ++-
 tcp.c   |  2 +-
 udp.c   |  4 ++--
 util.c  | 12 +++++++++---
 util.h  |  2 ++
 5 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/passt.h b/passt.h
index ae3035f..0ef1897 100644
--- a/passt.h
+++ b/passt.h
@@ -67,7 +67,8 @@ extern char pkt_buf		[PKT_BUF_BYTES];
 
 extern char *ip_proto_str[];
 #define IP_PROTO_STR(n)							\
-	(((n) <= IPPROTO_SCTP && ip_proto_str[(n)]) ? ip_proto_str[(n)] : "?")
+	(((uint8_t)(n) <= IPPROTO_SCTP && ip_proto_str[(n)]) ?		\
+			  ip_proto_str[(n)] : "?")
 
 #include <resolv.h>	/* For MAXNS below */
 
diff --git a/tcp.c b/tcp.c
index 839bf30..18f07b6 100644
--- a/tcp.c
+++ b/tcp.c
@@ -2518,7 +2518,7 @@ eintr:
 	}
 
 
-	if (n < (seq_from_tap - conn->seq_from_tap)) {
+	if (n < (int)(seq_from_tap - conn->seq_from_tap)) {
 		partial_send = 1;
 		conn->seq_from_tap += n;
 		tcp_send_to_tap(c, conn, 0, now);
diff --git a/udp.c b/udp.c
index 15e0c96..e1a9ecb 100644
--- a/udp.c
+++ b/udp.c
@@ -684,7 +684,7 @@ void udp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events,
 		cur_mh->msg_iov = &udp6_l2_iov_tap[0];
 		msg_i = msglen = iov_in_msg = 0;
 
-		for (i = 0; i < n; i++) {
+		for (i = 0; i < (unsigned)n; i++) {
 			struct udp6_l2_buf_t *b = &udp6_l2_buf[i];
 			size_t ip_len, iov_len;
 
@@ -770,7 +770,7 @@ void udp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events,
 		cur_mh->msg_iov = &udp4_l2_iov_tap[0];
 		msg_i = msglen = iov_in_msg = 0;
 
-		for (i = 0; i < n; i++) {
+		for (i = 0; i < (unsigned)n; i++) {
 			struct udp4_l2_buf_t *b = &udp4_l2_buf[i];
 			size_t ip_len, iov_len;
 			in_addr_t s_addr;
diff --git a/util.c b/util.c
index 7a3ea51..46a539b 100644
--- a/util.c
+++ b/util.c
@@ -342,7 +342,9 @@ int timespec_diff_ms(struct timespec *a, struct timespec *b)
  */
 void bitmap_set(uint8_t *map, int bit)
 {
-	map[bit / 8] |= 1 << (bit % 8);
+	unsigned long *word = (unsigned long *)map + BITMAP_WORD(bit);
+
+	*word |= BITMAP_BIT(bit);
 }
 
 /**
@@ -352,7 +354,9 @@ void bitmap_set(uint8_t *map, int bit)
  */
 void bitmap_clear(uint8_t *map, int bit)
 {
-	map[bit / 8] &= ~(1 << (bit % 8));
+	unsigned long *word = (unsigned long *)map + BITMAP_WORD(bit);
+
+	*word &= ~BITMAP_BIT(bit);
 }
 
 /**
@@ -364,7 +368,9 @@ void bitmap_clear(uint8_t *map, int bit)
  */
 int bitmap_isset(const uint8_t *map, int bit)
 {
-	return map[bit / 8] & (1 << bit % 8);
+	unsigned long *word = (unsigned long *)map + BITMAP_WORD(bit);
+
+	return *word & BITMAP_BIT(bit);
 }
 
 /**
diff --git a/util.h b/util.h
index 63cd8f9..800a91d 100644
--- a/util.h
+++ b/util.h
@@ -43,6 +43,8 @@ void debug(const char *format, ...);
 #define ROUND_DOWN(x, y)	((x) & ~((y) - 1))
 #define ROUND_UP(x, y)		(((x) + (y) - 1) & ~((y) - 1))
 
+#define BITMAP_BIT(n)		(1UL << (n) % (sizeof(long) * 8))
+#define BITMAP_WORD(n)		(n / (sizeof(long) * 8))
 
 #define SWAP(a, b)							\
 	do {								\
-- 
@@ -43,6 +43,8 @@ void debug(const char *format, ...);
 #define ROUND_DOWN(x, y)	((x) & ~((y) - 1))
 #define ROUND_UP(x, y)		(((x) + (y) - 1) & ~((y) - 1))
 
+#define BITMAP_BIT(n)		(1UL << (n) % (sizeof(long) * 8))
+#define BITMAP_WORD(n)		(n / (sizeof(long) * 8))
 
 #define SWAP(a, b)							\
 	do {								\
-- 
2.33.0