diff --git a/lib/irc/mode.ml b/lib/irc/mode.ml
index c1a4991..22d83a2 100644
--- a/lib/irc/mode.ml
+++ b/lib/irc/mode.ml
@@ -148,6 +148,55 @@ module Parse = struct
       ~init:Set.{ add = empty; rem = empty }
       ~add:(fun ms m -> Set.{ add = add m ms.add; rem = remove m ms.rem })
       ~rem:(fun ms m -> Set.{ add = remove m ms.add; rem = add m ms.rem })
+
+  type ('a, 'b) set_or_unset =
+    | Set of 'a
+    | Unset of 'b
+
+  type chan_modes = {
+    chan_modes : Set.change;
+    chan_key : (string, string) set_or_unset option;
+    chan_limit : (int, unit) set_or_unset option;
+    chan_priv : (chan_b * (string, string) set_or_unset) list;
+  }
+
+  let chan_modes_add (args, modes) = function
+    | #chan_a -> fail "TODO: + type A modes"
+    | #chan_b -> fail "TODO: + type B modes"
+    | #chan_c -> fail "TODO: + type C modes"
+    | #chan_d as m ->
+      let chan_modes = {
+        Set.add = Set.add m modes.chan_modes.add;
+        Set.rem = Set.remove m modes.chan_modes.rem;
+      } in
+      args, { modes with chan_modes }
+
+  let chan_modes_rem (args, modes) = function
+    | #chan_a -> fail "TODO: - type A modes"
+    | #chan_b -> fail "TODO: - type B modes"
+    | #chan_c -> fail "TODO: - type C modes"
+    | #chan_d as m ->
+      let chan_modes = {
+        Set.add = Set.remove m modes.chan_modes.add;
+        Set.rem = Set.add m modes.chan_modes.rem;
+      } in
+      args, { modes with chan_modes }
+
+  let chan_modes str args =
+    let modes = {
+      chan_modes = Set.no_change;
+      chan_key = None;
+      chan_limit = None;
+      chan_priv = [];
+    } in
+    let _, modes =
+      parse_mode_set str
+        ~of_char:of_char_chan
+        ~init:(args, modes)
+        ~add:chan_modes_add
+        ~rem:chan_modes_rem
+    in
+    { modes with chan_priv = List.rev modes.chan_priv }
 end
 
 
diff --git a/lib/irc/mode.mli b/lib/irc/mode.mli
index a5ee4c0..2adce0e 100644
--- a/lib/irc/mode.mli
+++ b/lib/irc/mode.mli
@@ -73,5 +73,17 @@ module Parse : sig
 
   type user_modes = Set.change
 
+  type ('a, 'b) set_or_unset =
+    | Set of 'a
+    | Unset of 'b
+
+  type chan_modes = {
+    chan_modes : Set.change;
+    chan_key : (string, string) set_or_unset option;
+    chan_limit : (int, unit) set_or_unset option;
+    chan_priv : (chan_b * (string, string) set_or_unset) list;
+  }
+
   val user_modes : string -> user_modes
+  val chan_modes : string -> string list -> chan_modes
 end