diff --git a/src/libsystemd-network/sd-radv.c b/src/libsystemd-network/sd-radv.c
index 28da73c8d5..2386fbd644 100644
--- a/src/libsystemd-network/sd-radv.c
+++ b/src/libsystemd-network/sd-radv.c
@@ -611,8 +611,8 @@ _public_ int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p, bool dynamic) {
 }
 
 _public_ sd_radv_prefix *sd_radv_remove_prefix(sd_radv *ra,
-                                               struct in6_addr *prefix,
-                                               uint8_t prefixlen) {
+                                               const struct in6_addr *prefix,
+                                               unsigned char prefixlen) {
         sd_radv_prefix *cur, *next;
 
         assert_return(ra, NULL);
@@ -772,7 +772,7 @@ _public_ sd_radv_prefix *sd_radv_prefix_unref(sd_radv_prefix *p) {
         return mfree(p);
 }
 
-_public_ int sd_radv_prefix_set_prefix(sd_radv_prefix *p, struct in6_addr *in6_addr,
+_public_ int sd_radv_prefix_set_prefix(sd_radv_prefix *p, const struct in6_addr *in6_addr,
                                        unsigned char prefixlen) {
         assert_return(p, -EINVAL);
         assert_return(in6_addr, -EINVAL);
diff --git a/src/systemd/sd-radv.h b/src/systemd/sd-radv.h
index e319a82dbf..9d4ba87447 100644
--- a/src/systemd/sd-radv.h
+++ b/src/systemd/sd-radv.h
@@ -64,8 +64,8 @@ int sd_radv_set_managed_information(sd_radv *ra, int managed);
 int sd_radv_set_other_information(sd_radv *ra, int other);
 int sd_radv_set_preference(sd_radv *ra, unsigned preference);
 int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p, bool dynamic);
-sd_radv_prefix *sd_radv_remove_prefix(sd_radv *ra, struct in6_addr *prefix,
-                                      uint8_t prefixlen);
+sd_radv_prefix *sd_radv_remove_prefix(sd_radv *ra, const struct in6_addr *prefix,
+                                      unsigned char prefixlen);
 int sd_radv_set_rdnss(sd_radv *ra, uint32_t lifetime,
                       const struct in6_addr *dns, size_t n_dns);
 int sd_radv_set_dnssl(sd_radv *ra, uint32_t lifetime, char **search_list);
@@ -75,7 +75,7 @@ int sd_radv_prefix_new(sd_radv_prefix **ret);
 sd_radv_prefix *sd_radv_prefix_ref(sd_radv_prefix *ra);
 sd_radv_prefix *sd_radv_prefix_unref(sd_radv_prefix *ra);
 
-int sd_radv_prefix_set_prefix(sd_radv_prefix *p, struct in6_addr *in6_addr,
+int sd_radv_prefix_set_prefix(sd_radv_prefix *p, const struct in6_addr *in6_addr,
                               unsigned char prefixlen);
 int sd_radv_prefix_set_onlink(sd_radv_prefix *p, int onlink);
 int sd_radv_prefix_set_address_autoconfiguration(sd_radv_prefix *p,