diff --git a/src/unix/bsd/mod.rs b/src/unix/bsd/mod.rs
index cf58a026a4770aa088a05f3c5e21f595ae7f5b9e..bacfb41189bc81d2cdc8190f471b06556eada083 100644
--- a/src/unix/bsd/mod.rs
+++ b/src/unix/bsd/mod.rs
@@ -183,6 +183,7 @@ pub const IP_MULTICAST_IF: ::c_int = 9;
 pub const IP_MULTICAST_TTL: ::c_int = 10;
 pub const IP_MULTICAST_LOOP: ::c_int = 11;
 
+pub const IPV6_UNICAST_HOPS: ::c_int = 4;
 pub const IPV6_MULTICAST_IF: ::c_int = 9;
 pub const IPV6_MULTICAST_HOPS: ::c_int = 10;
 pub const IPV6_MULTICAST_LOOP: ::c_int = 11;
diff --git a/src/unix/notbsd/mod.rs b/src/unix/notbsd/mod.rs
index d3033bee26cf1b37d84b3256f6ffd6a782dd3039..92dfad6b9f2be1633d5d7eb5429af35a526d211e 100644
--- a/src/unix/notbsd/mod.rs
+++ b/src/unix/notbsd/mod.rs
@@ -576,6 +576,7 @@ pub const IP_HDRINCL: ::c_int = 3;
 pub const IP_ADD_MEMBERSHIP: ::c_int = 35;
 pub const IP_DROP_MEMBERSHIP: ::c_int = 36;
 pub const IP_TRANSPARENT: ::c_int = 19;
+pub const IPV6_UNICAST_HOPS: ::c_int = 16;
 pub const IPV6_MULTICAST_IF: ::c_int = 17;
 pub const IPV6_MULTICAST_HOPS: ::c_int = 18;
 pub const IPV6_MULTICAST_LOOP: ::c_int = 19;