Deal with RFC 6733 change to Vendor-Specific-Application-Id

RFC 6733 has changed the arity of Vendor-Id in this Grouped AVP, from 1*
in RFC 3588 to 1 in RFC 6773. This impacts the generated dictionary
modules: Vendor-Id is expected to be list-valued in the 3588 dictionary,
integer-valued in the 6733 dictionary. This, in turn, breaks the
independence of capabilities configuration on a service or transport
from the dictionary that will be used to encode an outgoing CER or CEA.

This commit fixes this by massaging any Vendor-Specific-Application-Id
config as appropriate when constructing CER or CEA for a given
dictionary.

2 files changed, 67 insertions, 4 deletions

diff --git a/lib/diameter/src/base/diameter_capx.erl b/lib/diameter/src/base/diameter_capx.erl
index 715b15628c..9a443fead0 100644
--- a/lib/diameter/src/base/diameter_capx.erl
+++ b/lib/diameter/src/base/diameter_capx.erl
@@ -172,7 +172,50 @@ ipaddr(A) ->
 bCER(#diameter_caps{} = Rec, Dict) ->
     Values = lists:zip(Dict:'#info-'(diameter_base_CER, fields),
                        tl(tuple_to_list(Rec))),
-    Dict:'#new-'(diameter_base_CER, Values).
+    Dict:'#new-'(diameter_base_CER, [{K, map(K, V, Dict)}
+                                     || {K,V} <- Values]).
+
+%% map/3
+%%
+%% Deal with differerences in common dictionary AVP's to make changes
+%% transparent in service/transport config. In particular, one
+%% annoying difference between RFC 3588 and RFC 6733.
+%%
+%% RFC 6773 changes the definition of Vendor-Specific-Application-Id,
+%% giving Vendor-Id arity 1 instead of 3588's 1*. This causes woe
+%% since the corresponding dictionaries expect different values for a
+%% 'Vendor-Id': a list for 3588, an integer for 6733.
+
+map('Vendor-Specific-Application-Id', L, Dict) ->
+    Rec = Dict:'#new-'('diameter_base_Vendor-Specific-Application-Id', []),
+    Def = Dict:'#get-'('Vendor-Id', Rec),
+    [vsa(V, Def) || V <- L];
+map(_, V, _) ->
+    V.
+
+vsa({_, N, _, _} = Rec, [])
+  when is_integer(N) ->
+    setelement(2, Rec, [N]);
+
+vsa({_, [N], _, _} = Rec, undefined)
+  when is_integer(N) ->
+    setelement(2, Rec, N);
+
+vsa([_|_] = L, Def) ->
+    [vid(T, Def) || T <- L];
+
+vsa(T, _) ->
+    T.
+
+vid({'Vendor-Id' = K, N}, [])
+  when is_integer(N) ->
+    {K, [N]};
+
+vid({'Vendor-Id' = K, [N]}, undefined) ->
+    {K, N};
+
+vid(T, _) ->
+    T.
 
 %% rCER/3
 %%
diff --git a/lib/diameter/test/diameter_capx_SUITE.erl b/lib/diameter/test/diameter_capx_SUITE.erl
index a4e4195a19..6fe6682571 100644
--- a/lib/diameter/test/diameter_capx_SUITE.erl
+++ b/lib/diameter/test/diameter_capx_SUITE.erl
@@ -34,6 +34,7 @@
 
 %% testcases
 -export([start/1,
+         vendor_id/1,
          start_services/1,
          add_listeners/1,
          s_no_common_application/1,
@@ -69,7 +70,7 @@
 -define(HOST(Name), Name ++ "." ++ ?REALM).
 
 %% Config for diameter:start_service/2.
--define(SERVICE(Name),
+-define(SERVICE,
         [{'Origin-Realm', ?REALM},
          {'Host-IP-Address', [?ADDR]},
          {'Vendor-Id', 12345},
@@ -103,6 +104,7 @@ suite() ->
     [{timetrap, {seconds, 60}}].
 
 all() -> [start,
+          vendor_id,
           start_services,
           add_listeners]
       ++ [{group, D, P} || D <- ?DICTS, P <- [[], [parallel]]]
@@ -156,9 +158,27 @@ tc() ->
 start(_Config) ->
     ok = diameter:start().
 
+%% Ensure that both integer and list-valued vendor id's can be
+%% configured in a 'Vendor-Specific-Application-Id, the arity having
+%% changed between RFC 3588 and RFC 6733.
+vendor_id(_Config) ->
+    [] = ?util:run([[fun vid/1, V] || V <- [1, [1], [1,2], x]]).
+
+vid(V) ->
+    RC = diameter:start_service(make_ref(),
+                                [{'Vendor-Specific-Application-Id',
+                                  [[{'Vendor-Id', V}]]}
+                                 | ?SERVICE]),
+    vid(V, RC).
+
+vid(x, {error, _}) ->
+    ok;
+vid(_, ok) ->
+    ok.
+
 start_services(_Config) ->
-    ok = diameter:start_service(?SERVER, ?SERVICE(?SERVER)),
-    ok = diameter:start_service(?CLIENT, ?SERVICE(?CLIENT)).
+    ok = diameter:start_service(?SERVER, ?SERVICE),
+    ok = diameter:start_service(?CLIENT, ?SERVICE).
 
 %% One server that responds only to base accounting, one that responds
 %% to both this and the common application. Share a common service just