socket-util: introduce in_addr_is_multicast

This patch add support to test whether a internet
address is multicast or not.

2 files changed, 14 insertions, 0 deletions

diff --git a/src/basic/in-addr-util.c b/src/basic/in-addr-util.c
index 3b06cb00ad..3927df2955 100644
--- a/src/basic/in-addr-util.c
+++ b/src/basic/in-addr-util.c
@@ -66,6 +66,18 @@ int in_addr_is_link_local(int family, const union in_addr_union *u) {
         return -EAFNOSUPPORT;
 }
 
+int in_addr_is_multicast(int family, const union in_addr_union *u) {
+        assert(u);
+
+        if (family == AF_INET)
+                return IN_MULTICAST(be32toh(u->in.s_addr));
+
+        if (family == AF_INET6)
+                return IN6_IS_ADDR_MULTICAST(&u->in6);
+
+        return -EAFNOSUPPORT;
+}
+
 bool in4_addr_is_localhost(const struct in_addr *a) {
         assert(a);
 
diff --git a/src/basic/in-addr-util.h b/src/basic/in-addr-util.h
index 64a812c322..51a5aa67e4 100644
--- a/src/basic/in-addr-util.h
+++ b/src/basic/in-addr-util.h
@@ -39,6 +39,8 @@ struct in_addr_data {
 bool in4_addr_is_null(const struct in_addr *a);
 int in_addr_is_null(int family, const union in_addr_union *u);
 
+int in_addr_is_multicast(int family, const union in_addr_union *u);
+
 bool in4_addr_is_link_local(const struct in_addr *a);
 int in_addr_is_link_local(int family, const union in_addr_union *u);