Project

General

Profile

Libosmocore » History » Version 9

laforge, 02/19/2016 10:49 PM

1 1 laforge
[[PageOutline]]
2
= libosmocore =
3
4
libosmocore is a library with various utility functions that were originally developed as part of 
5
the [wiki:OpenBSC] project, but which are of a more generic nature and thus useful to (at least)
6 8 laforge
other programs that we develop in the sphere of Free Software / Open Source mobile communications.
7 1 laforge
8
There is no clear scope of it.  We simply move all shared code between [wiki:OsmocomBB] and [wiki:OpenBSC]
9
in this library to avoid code duplication.
10
11 9 laforge
== Browsing its source code ==
12
13
You can do that using our cgit installation at http://cgit.osmocom.org/cgit/libosmocore/
14 1 laforge
== Obtaining it ==
15
16
When you download and build [wiki:OsmocomBB], then libosmocore is automatically part of the package,
17
no special action is required.
18
19
If you want to obtain a standalone version of libosmocore, you can use the following git URL:
20 5 laforge
21 1 laforge
{{{git clone git://git.osmocom.org/libosmocore.git}}}
22
23 7 tsaitgaist
== Compiling and installing it ==
24
25
To compile and install it as standalone:
26
27
{{{
28
cd libosmocore/
29
autoreconf -i
30
./configure
31
make
32
sudo make install
33
cd ..
34
}}}
35
36 1 laforge
== Licensing ==
37
38
This library is GPL licensed, as the code is taken from the similarly GPL-licensed OpenBSC codebase.
39
40
This means you '''cannot use this library from non-GPL licensed code without infringing copyright!
41
42
== Features ==
43
44
=== Select loop abstraction ===
45
This is implemented in select.[ch] and enables you to build complex asynchronous/non-blocking I/O
46
programs in a single thread.
47
48
=== Message buffer handling ===
49
Inspired by the Linux kernel {{{struct sk_buff}}}, this is our message buffer {{{struct msgb}}}
50
implementation.  It provides handling of packet buffers, putting them in queues, prepending
51
and appending data to it, etc.
52
53
=== Bitvector ===
54
A convenient set of routines to deal with bit-vectors in C.  This was originally written
55
for rest-octet parsing.
56
57
=== TLV handling ===
58
The GSM Layer3 and above are full of TV / TLV / TL16V and other data fields.  Our implementation
59
provides parser and generator functions, tightly coupled to {{{struct msgb}}}
60
61
=== Timers ===
62
Provides a timer core where you can register timers with a callback function. The function
63
is called when the timer expires.
64
65
=== Comp128v1 ===
66
A Comp128v1 implementation by Sylvain Munaut is included.
67
68 6 laforge
=== Rate Counter ===
69
Provides infrastructure for maintaining ''rate counters'', i.e. counters that can be incremented
70
and will also keep track of the rate of events per second, minute, hour and day.  A group of rate
71
counters is defined as an abstract ''class'', from which you can then allocate instances.  The
72
''class'' description includes information about the counter names.
73
74
75 3 laforge
=== Protocol helper code ===
76 1 laforge
77 3 laforge
==== GSM utils ====
78
 * conversion functions for ARFCN, RxLevel, 7bit GSM character set, power level, frame numbers, ...
79
80
==== GSM 04.08 ====
81
 * extensive header files for the GSM 04.08 (Layer 3 RR/MM/CC) messages
82
 * TLV parser definitions to parse the optional IEs
83
 * utility functions such as
84
  * human readable strings for RR cause names
85
  * converting GSM Mobile Identities (MI) to string and back
86
 * encoding and decoding functions for call control IEs
87
88 6 laforge
==== GSM 08.08 (A Interface) ====
89
 * API to wrap 04.08 messages in BSSMAP/DTAP message
90
 * TLV parser definitions
91
92 4 laforge
==== GSM 08.58 (A-bis RSL) ====
93 3 laforge
 * header file with structure and enum definitions for GSM 08.58 protocol
94
 * TLV parser definitions for RSL optional IEs
95 1 laforge
 * human readable strings for RSL Error values and RLM cause values
96 4 laforge
 * encoding and decoding of RSL channel number
97
98
==== GSM 12.21 (A-bis OML) ====
99
 * header file with structure and enum definitions for GSM 12.21 (and 08.59) protocol
100 3 laforge
101
==== GSM 04.11 (SMS) ====
102 1 laforge
 * header file with structure and enum definitions for GSM 04.11 (SMS RP and CP layers) protocol
103 3 laforge
104 1 laforge
=== Talloc memory allocator ===
105 6 laforge
The talloc memory allocator from the Samba project is (optionally) part of libosmocore.
106
It provides hierarchical memory allocation and extensive debugging features such as dumping
107
the currently allocated objects (at runtime) to the console.
108 1 laforge
109
=== Logging framework ===
110 6 laforge
A generic logging implementation, supporting a dynamic number of 'log targets', understanding
111
the notion of log levels and log categories.  Filtering based on levels and categories is
112
implemented in the core, while context-specific filtering can be implemented by the application
113
using libosmocore.
114 3 laforge
 * logging with various log levels for various subsystems inside the application
115
 * logging to stderr, syslog or application-defined targets
116
 * runtime reconfigurable per-subsystem log levels
117
 * timestamping of log lines
118
 * colorized log output
119
120
=== Write Queue ===
121
122
This is a write queue implementation on top of libosmocore's select loop abstraction.
123
It allows you to simply say "write this msg_buff to this file descriptor as soon as
124
the file descriptor is writable".
125 2 laforge
126
== Development Cycle ==
127
128
As we are still developing the GSM protocol stacks on the network side (OpenBSC) and phone side (OsmocomBB),
129
every so often there is a need to add some new code to libosmocore.  Even worse, we sometimes need to break
130
the API and ABI of the library.
131
132
However, by keeping libosmocore in a separate git repository, we run into one problem: Checking out an old
133
version of e.g. OpenBSC or OsmocomBB will result in failed builds, as we don't remember which old version
134
of libosmocore was required.  This makes debugging and things like git bisect very hard to impossible.
135
136
In order to solve this problem, we use [http://github.com/apenwarr/git-subtree git-subtree] to import the
137
full libosmocore.git repository into OsmocomBB.
138
139
This way, we ensure that there is always a compatible version of libosmocore inside the tree if we check out
140
old OsmocomBB versions from git.
141
142
=== Making changes to libosmocore ===
143
144
 '''NEVER COMMIT CHANGES DIRECTLY TO osmocom-bb.git:src/shared/libosmocore'''
145
146
Instead, use the following process:
147
 1. make your changes to your local copy of libosmocore
148
 1. test them together with OsmocomBB and OpenBSC
149
 1. test if libosmocore still builds for both host and target (ARM)
150
 1. create a ''diff'' of your local libosmocore changes
151
 1. apply that diff to the libosmocore.git repository
152
 1. use the script in osmocom-bb.git/src/shared/update-libosmocore.sh (uses git-subtree) to import your changes from libosmocore.git
153
 1. test + commit your OsmocomBB changes that depend on the newly introduced code to libosmocore
154
155
It is important that the steps are followed in the order state above to ensure consistency of our repositories
Add picture from clipboard (Maximum size: 48.8 MB)