1.2.1. OpenSER Modules

The following modules must be loaded before this module:

• No dependencies on other OpenSER modules.

1.2.2. External Libraries or Applications

The following libraries or applications must be installed before running OpenSER with this module loaded:

• None.

1.3.1. max_limit (integer)

Set an upper limit for the max-forward value in the outgoing requests. This is the default value if the header is not present in the incoming request. If the header is present, the decremented value is not allowed to exceed this max_limits - if it does, the header value will by decreased to "max_limit".

It's a good way to deal with clients which set max-forward value to a quite high values (like 80).

Default value is "16".

...
modparam("maxfwd", "max_limit", 8)
...

1.4.1. mf_process_maxfwd_header(max_value)

If no Max-Forward header is present in the received request, a header will be added having the original value equal with "max_value". An OK code is returned by the function.

If a Max-Forward header is already present, its value will be decremented. If after this operation its value will be positive non-zero, an OK code will be returned. Otherwise (for a zero value) an error code will be returned. Note that an error code will be also returned if the SIP message couldn't be parsed or if the Max-Forward header's body invalid (non numerical string or negative numerical value).

Meaning of the parameters is as follows:

• max_value - Value to be added if there is no Max-Forwards header field in the message.

...
# initial sanity checks -- messages with
# max_forwards==0, or excessively long requests
if (!mf_process_maxfwd_header("10")) {
	sl_send_reply("483","Too Many Hops");
	break;
};
...