From 502189ba42469d3332bc0658caa2bd0de1e3fcb9 Mon Sep 17 00:00:00 2001 From: Anders Svensson Date: Mon, 24 Aug 2015 16:14:49 +0200 Subject: Add service_opt() strict_mbit There are differing opinions on whether or not reception of an arbitrary AVP setting the M-bit is an error. 1.3.4 of RFC 6733 says this about how an existing Diameter application may be modified: o The M-bit allows the sender to indicate to the receiver whether or not understanding the semantics of an AVP and its content is mandatory. If the M-bit is set by the sender and the receiver does not understand the AVP or the values carried within that AVP, then a failure is generated (see Section 7). It is the decision of the protocol designer when to develop a new Diameter application rather than extending Diameter in other ways. However, a new Diameter application MUST be created when one or more of the following criteria are met: M-bit Setting An AVP with the M-bit in the MUST column of the AVP flag table is added to an existing Command/Application. An AVP with the M-bit in the MAY column of the AVP flag table is added to an existing Command/Application. The point here is presumably interoperability: that the command grammar should specify explicitly what mandatory AVPs much be understood, and that anything more is an error. On the other hand, 3.2 says thus about command grammars: avp-name = avp-spec / "AVP" ; The string "AVP" stands for *any* arbitrary AVP ; Name, not otherwise listed in that Command Code ; definition. The inclusion of this string ; is recommended for all CCFs to allow for ; extensibility. This renders 1.3.4 pointless unless "*any* AVP" is qualified by "not setting the M-bit", since the sender can effectively violate 1.3.4 without this necessitating an error at the receiver. If clients add arbitrary AVPs setting the M-bit then request handling becomes more implementation-dependent. The current interpretation in diameter is strict: if a command grammar doesn't explicitly allow an AVP setting the M-bit then reception of such an AVP is regarded as an error. The strict_mbit option now allows this behaviour to be changed, false turning all responsibility for the M-bit over to the user. --- lib/diameter/src/base/diameter_config.erl | 3 +++ 1 file changed, 3 insertions(+) (limited to 'lib/diameter/src/base/diameter_config.erl') diff --git a/lib/diameter/src/base/diameter_config.erl b/lib/diameter/src/base/diameter_config.erl index 89b26707ad..242b6b4d08 100644 --- a/lib/diameter/src/base/diameter_config.erl +++ b/lib/diameter/src/base/diameter_config.erl @@ -646,6 +646,7 @@ make_config(SvcName, Opts) -> {?NOMASK, sequence}, {nodes, restrict_connections}, {16#FFFFFF, incoming_maxlen}, + {true, strict_mbit}, {true, string_decode}, {[], spawn_opt}]), @@ -684,12 +685,14 @@ opt(K, false = B) K == use_shared_peers; K == monitor; K == restrict_connections; + K == strict_mbit; K == string_decode -> B; opt(K, true = B) when K == share_peers; K == use_shared_peers; + K == strict_mbit; K == string_decode -> B; -- cgit v1.2.3