proto_hep Module

Ionut-Razvan Ionita

OpenSIPS Solutions

Table of Contents

1. Admin Guide
1.1. Overview
1.2. Dependencies
1.2.1. OpenSIPS Modules
1.2.2. External Libraries or Applications
1.3. Exported Parameters
1.3.1. hep_port (integer)
1.3.2. hep_send_timeout (integer)
1.3.3. hep_max_msg_chunks (integer)
1.3.4. hep_async (integer)
1.3.5. hep_async_max_postponed_chunks (integer)
1.3.6. hep_capture_id (integer)
1.3.7. hep_async_local_connect_timeout (integer)
1.3.8. hep_async_local_write_timeout (integer)
2. Developer Guide
2.1. Available Functions
2.1.1. pack_hep(from, to, proto, payload, plen, retbuf, retlen)
2.1.2. register_hep_cb(cb)
2.1.3. hep_version

List of Examples

1.1. Set hep_port parameter
1.2. Set hep_send_timeout parameter
1.3. Set hep_max_msg_chunks parameter
1.4. Set hep_async parameter
1.5. Set hep_async_max_postponed_chunks parameter
1.6. Set hep_capture_id parameter
1.7. Set hep_async_local_connect_timeout parameter
1.8. Set hep_async_local_write_timeout parameter

Chapter 1. Admin Guide

1.1. Overview

The proto_hep module is a transport module which implements hepV1 and hepV2 UDP-based communication and hepV3 TCP-based communication. It also offers an API with which you can register callbacks which are called after the HEP header is parsed and also can pack sip messages to HEP messages.The unpacking part is done internally.

Once loaded, you will be able to define HEP listeners in your configuration file by adding their IP and, optionally, a listening port. You can define both TCP and UDP listeners. On UDP you will be able to receive HEP v1, v2 and v3 packets, on TCP only HEPv3.

#HEPv3 listener
listen = hep_tcp: 		# change the listening IP
#HEPv1, v2, v3 listener
listen = hep_udp: 		# change the listening IP

1.2. Dependencies

1.2.1. OpenSIPS Modules

The following modules must be loaded before this module:

  • None.

1.2.2. External Libraries or Applications

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

  • None.

1.3. Exported Parameters

1.3.1. hep_port (integer)

The default port to be used by all TCP/UDP listeners.

Default value is 5656.

Example 1.1. Set hep_port parameter

modparam("proto_hep", "hep_port", 6666)

1.3.2. hep_send_timeout (integer)

Time in milliseconds after a TCP connection will be closed if it is not available for blocking writing in this interval (and OpenSIPS wants to send something on it).

Default value is 100 ms.

Example 1.2. Set hep_send_timeout parameter

modparam("proto_hep", "hep_send_timeout", 200)

1.3.3. hep_max_msg_chunks (integer)

The maximum number of chunks in which a HEP message is expected to arrive via TCP. If a received packet is more fragmented than this, the connection is dropped (either the connection is very overloaded and this leads to high fragmentation - or we are the victim of an ongoing attack where the attacker is sending very fragmented traffic in order to decrease server performance).

Default value is 32.

Example 1.3. Set hep_max_msg_chunks parameter

modparam("proto_hep", "hep_max_msg_chunks", 8)

1.3.4. hep_async (integer)

Specifies whether the TCP connect and write operations should be done in an asynchronous mode (non-blocking connect and write) or not. If disabled, OpenSIPS will block and wait for TCP operations like connect and write.

Default value is 1 (enabled).

Example 1.4. Set hep_async parameter

modparam("proto_hep", "hep_async", 0)

1.3.5. hep_async_max_postponed_chunks (integer)

If hep_async is enabled, this specifies the maximum number of HEP messages that can be stashed for later/async writing. If the connection pending writes exceed this number, the connection will be marked as broken and dropped.

Default value is 32.

Example 1.5. Set hep_async_max_postponed_chunks parameter

modparam("proto_hep", "hep_async_max_postponed_chunks", 16)

1.3.6. hep_capture_id (integer)

The parameter indicate the capture agent ID for HEPv2/v3 protocol. Limitation: 16-bit integer.

Default value is "1".

Example 1.6. Set hep_capture_id parameter

modparam("proto_hep", "hep_capture_id", 234)

1.3.7. hep_async_local_connect_timeout (integer)

If hep_async is enabled, this specifies the number of milliseconds that a connect will be tried in blocking mode (optimization). If the connect operation lasts more than this, the connect will go to async mode and will be passed to TCP MAIN for polling.

Default value is 100 ms.

Example 1.7. Set hep_async_local_connect_timeout parameter

modparam("proto_hep", "hep_async_local_connect_timeout", 200)

1.3.8. hep_async_local_write_timeout (integer)

If hep_async is enabled, this specifies the number of milliseconds that a write op will be tried in blocking mode (optimization). If the write operation lasts more than this, the write will go to async mode and will be passed to bin MAIN for polling.

Default value is 10 ms.

Example 1.8. Set hep_async_local_write_timeout parameter

modparam("proto_hep", "tcp_async_local_write_timeout", 100)

Chapter 2. Developer Guide

2.1. Available Functions

2.1.1.  pack_hep(from, to, proto, payload, plen, retbuf, retlen)

The function packs connection details and sip message into HEP message. It's your job to free both the old and the new buffer.

Meaning of the parameters is as follows:

  • sockaddr_union *from - sockaddr_union describing sending socket

  • sockaddr_union *to - sockaddr_union describing receiving socket

  • int proto - protocol used in hep header;

  • char *payload SIP payload buffer

  • int plen SIP payload buffer length

  • char **retbuf HEP message buffer

  • int *retlen HEP message buffer length

2.1.2.  register_hep_cb(cb)

The function register callbacks to be called whenever a HEP message is received. The callbacks parameters are struct hep_desc*(see hep.h for details) a structure that holds all details about the hep header and the receive_info* structure. The callback can return HEP_SCRIPT_SKIP which stops the HEP message from being passed thrrough scripts.

Meaning of the parameters is as follows:

  • hep_cb_t cb HEP callback

2.1.3.  hep_version

Current version of hep used.