socket-util: add helper for generically initializing sockaddr_union from in_addr_union

src/basic/socket-util.c

@@ -400,6 +400,41 @@ const union in_addr_union *sockaddr_in_addr(const struct sockaddr *_sa) {
         }
 }
 
+int sockaddr_set_in_addr(
+                union sockaddr_union *u,
+                int family,
+                const union in_addr_union *a,
+                uint16_t port) {
+
+        assert(u);
+        assert(a);
+
+        switch (family) {
+
+        case AF_INET:
+                u->in = (struct sockaddr_in) {
+                        .sin_family = AF_INET,
+                        .sin_addr = a->in,
+                        .sin_port = htobe16(port),
+                };
+
+                return 0;
+
+        case AF_INET6:
+                u->in6 = (struct sockaddr_in6) {
+                        .sin6_family = AF_INET6,
+                        .sin6_addr = a->in6,
+                        .sin6_port = htobe16(port),
+                };
+
+                return 0;
+
+        default:
+                return -EAFNOSUPPORT;
+
+        }
+}
+
 int sockaddr_pretty(
                 const struct sockaddr *_sa,
                 socklen_t salen,