inany: Helper to test for various address types

Add helpers to determine if an inany is loopback, unspecified or
multicast, regardless of whether it's a "true" IPv6 address or an IPv4
address represented as v4-mapped.

Use the loopback helper to simplify tcp_splice_conn_from_sock() slightly.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

2 files changed, 53 insertions, 12 deletions

diff --git a/inany.h b/inany.h
index fe652ff..d110380 100644
--- a/inany.h
+++ b/inany.h
@@ -55,6 +55,56 @@ static inline bool inany_equals(const union inany_addr *a,
 	return IN6_ARE_ADDR_EQUAL(&a->a6, &b->a6);
 }
 
+/** inany_is_loopback() - Check if address is loopback
+ * @a:		IPv[46] address
+ *
+ * Return: true if @a is either ::1 or in 127.0.0.1/8
+ */
+static inline bool inany_is_loopback(const union inany_addr *a)
+{
+	const struct in_addr *v4 = inany_v4(a);
+
+	return IN6_IS_ADDR_LOOPBACK(&a->a6) || (v4 && IN4_IS_ADDR_LOOPBACK(v4));
+}
+
+/** inany_is_unspecified() - Check if address is unspecified
+ * @a:		IPv[46] address
+ *
+ * Return: true if @a is either :: or 0.0.0.0
+ */
+static inline bool inany_is_unspecified(const union inany_addr *a)
+{
+	const struct in_addr *v4 = inany_v4(a);
+
+	return IN6_IS_ADDR_UNSPECIFIED(&a->a6) ||
+		(v4 && IN4_IS_ADDR_UNSPECIFIED(v4));
+}
+
+/** inany_is_multicast() - Check if address is multicast or broadcast
+ * @a:		IPv[46] address
+ *
+ * Return: true if @a is IPv6 multicast or IPv4 multicast or broadcast
+ */
+static inline bool inany_is_multicast(const union inany_addr *a)
+{
+	const struct in_addr *v4 = inany_v4(a);
+
+	return IN6_IS_ADDR_MULTICAST(&a->a6) ||
+		(v4 && (IN4_IS_ADDR_MULTICAST(v4) ||
+			IN4_IS_ADDR_BROADCAST(v4)));
+}
+
+/** inany_is_unicast() - Check if address is specified and unicast
+ * @a:		IPv[46] address
+ *
+ * Return: true if @a is specified and a unicast address
+ */
+/* cppcheck-suppress unusedFunction */
+static inline bool inany_is_unicast(const union inany_addr *a)
+{
+	return !inany_is_unspecified(a) && !inany_is_multicast(a);
+}
+
 /** inany_from_af - Set IPv[46] address from IPv4 or IPv6 address
  * @aa:		Pointer to store IPv[46] address
  * @af:		Address family of @addr
diff --git a/tcp_splice.c b/tcp_splice.c
index 5b38a82..cdc09a4 100644
--- a/tcp_splice.c
+++ b/tcp_splice.c
@@ -449,29 +449,20 @@ bool tcp_splice_conn_from_sock(const struct ctx *c,
 			       struct tcp_splice_conn *conn, int s,
 			       const struct sockaddr *sa)
 {
-	const struct in_addr *a4;
 	union inany_addr aany;
 	in_port_t port;
 
 	ASSERT(c->mode == MODE_PASTA);
 
 	inany_from_sockaddr(&aany, &port, sa);
-	a4 = inany_v4(&aany);
-
-	if (a4) {
-		if (!IN4_IS_ADDR_LOOPBACK(a4))
-			return false;
-		conn->flags = 0;
-	} else {
-		if (!IN6_IS_ADDR_LOOPBACK(&aany.a6))
-			return false;
-		conn->flags = SPLICE_V6;
-	}
+	if (!inany_is_loopback(&aany))
+		return false;
 
 	if (setsockopt(s, SOL_TCP, TCP_QUICKACK, &((int){ 1 }), sizeof(int)))
 		flow_trace(conn, "failed to set TCP_QUICKACK on %i", s);
 
 	conn->f.type = FLOW_TCP_SPLICE;
+	conn->flags = inany_v4(&aany) ? 0 : SPLICE_V6;
 	conn->s[0] = s;
 
 	if (tcp_splice_new(c, conn, ref.port, ref.pif))