Planned for 1.0
* portability:
  o add at least one OS other than Linux
  o compile with at least one compiler other than GCC 
- stable API (freeze code base)
- advanced backend protocol capabilities
  (1/3): (un-)ordered send mode (i.e. for video streaming: QoS)
  (2/3): unicast/multicast 
  (3/3): encryption mode
- IPv6 support
- write generic streaming functionality with (see IDL):
  o input: any struct
  o ouput: pack/unpack functions (C-code)
- add at least one more backend
  o SCTP backend
  o job backend (simple process management)
  o XMMS remote control backend using libXMMS (optional: simple, but funny!) 
  o UDP backend


Changes between 0.7 and 0.8 (released 27-02-2006)
- major rewrite of the design with the following aims:
  o no backends - instead, a peer-to-peer layout is implemented
  o simplified plugins (with only 4 functions)
  o similar user API
  o much cleaner interfaces (internal API)
  o better test-cases
- though reimplemented, many parts could be reused, such as mutex pools,
  threading, signals, etc.
- direct access to filedescriptors is made possible with the psi_getFD() call
- a packet transfer protocol is not yet implemented

Changes between 0.6 and 0.7 (last changed 04-10-2005 - never released!)
- depends on PSIutil 1.5
- rename PSInet to PSIroads. Versioning remains the same
- added likely(cond) and unlikely(cond) macros for checks (in
  PSIutil/typedef.h)
- added -ffast-math flag to CFLAGS in Makefile
- changed author email host to project-psi.org
- peer_connect() function now creates a connecting client backend using the
  new PSI URI protocol
- new backend: auth_backend handles URI requests, which contains user, passwd
  and hostname fields. This backend is currently inactive, though.
- fixed some memleaks
- socket.[ch] now moved to TCP plugin. 
- target hostname is now resolved on backend creation with gethostbyname(). 
  Also, we now use a permanent connection for each peer (sethostent()) 
- sending behaviour changed: buffer is now partitioned into
  PSI_NET_BUFSIZE large blocks while sending
- assuming ISO C99 conformimng compiler - i.e., gcc 3.x or higher. Hence,
  code like the following is allowed:
    for (int i=0; i < x; i++) { ... } 
- C++ wrapper classes implemented
- connecting to services is now possible via sbe_connect(), which takes a
  transport backend (i.e., psi-tcp) as argument for peer communication. The
  target peer instance routes the request internally to service backend, and
  replies the backend address to the requesting backend
- improved POSIX thread handling:
  o using condition variables for thread synchronization (PSIutil/psi_signal_*())
  o pthread_detach() is called on thread cleanup
- polished API (see below)
- almost complete Doxygen documentation written
- mutex pools implemented
- peer message dispatcher: 
  o messages can be routed to service backends
  o peer generic (not backend specific) services can be implemented here
- fixed: COPYING updated
- API changes:
  o kill_backend() -> be_remove()
  o peer and be structs now contain a thread handle, which consists of a 
    thread ID (pthread_t), a thread attribute (pthread_attr_t) and a list 
    of mutexes (pthread_mutex_t)
  o removed all receive buffer parameters (rBuf)
  o socket_be_create() -> socket_be_init()
  o plugin->proto changed to plugin->id of type 'unsigned long'
  o renamed net_cap_t into psi_plugin_cap_t, which now is defined for
    each plugin
  o socket_close moved to tcp_backend and renamed to be_close (plugin field)
  o handle_kill_chunk now static in socket.c
  o chunk_t struct is now psi_chunk_t:
    - net_types_t removed
    - the chunk is split into a header (16 byte) and a variable length data 
      stream
    - header is defined as follows: 
      struct chunk_header {
        uint16_t      flags; /* chunk flags */
        uint16_t     req_id; /* request ID */
        psi_addr_t      src; /* optional - enabled by flags */
        psi_addr_t      dst; /* optional - enabled by flags */  
        uint32_t       size; /* length of data stream */
      };
  o sendMessage() -> psi_send() (slightly changed prototype)
  o socket_listen_thread_main() -> be_listen_loop() (now in backend.c)
  o socket_recv_thread_main() -> be_recv_loop() (now in be_recv.c)
  o socket_send_ordered()/socket_recv_ordered() -> be_send()/be_recv()
  o PSIutil: 'export' keyword renamed to PSIEXPORT (for C++ compatibility)
  o _null_send_fn() renamed to be_null_send_fn() (now exported)
  o psi_be_status_t now in backend.h (was in typedef.h)
  o replaced callback mechanism (be->event struct) by a much simpler
    variant. Note, that no mutex locking is performed internally.
  o be_getByID() -> peer_get_be()       (takes psi_addr_t as argument)
  o renamed some attribute macros to ATTRIBUTE_* (see PSIutil/typedef.h)
- API removals:
  - moved puri.[ch] to PSIutil/puri.[ch]:
    - puri_parse()
    - puri_assemble()
  - removed io_common/io_model_pthread files. This functionality is now located
    in PSIutil/psi_thread.[ch]:
    - exit_self()
    - join_from_background()
    - detach_self()  
  - moved some basic definitions from PSIroads/typedef.h to 
    PSIutil/typedef.h (i.e., export keyword)
  - removed 'mode' field in psi_backend_t struct
  - handle_check_passwd()
  - passwd_file in peer->set struct removed
  - peer_addUser() removed (for now)
  - obsolete phfs_backend.c removed
  - obsolete recv_packet.[ch] files removed
  - moved all plugin functions to PSIutil
  - removed convertChunk()
  - removed be_*_tcp functions 
  - removed PSI_PROTO_* macros
  - removed psi_proto_t type
  - removed psi_[dont]_free() functions (now in PSIutil/psi_thread)
  - removed be_cleanup() function (be_remove() handles this already)
  - removed (*destr)() field from psi_backend_t*, since backends are
    required to be malloc'ed anyway.
  - removed be_recv_raw() function from socket.[ch] (was not implemented)
  - obsolete notify_be_cleanup() removed
  - removed net_proto.[ch]:
    - killChunk()
    - dbgChunk()
    - dumpStream()
  - obsolete per packet compression removed (net_compress.[ch])
  - rBuf struct from socket_be_t
  - removed options.[ch]
  - removed some unused macros in typedef.h
  - psi_net_set_t struct and psi_net_t->set field removed
  - CI and CI_num fields in psi_net_t struct removed
  - removed authCall structs from psi_net_t struct
  - removed psi_cleanup_file()
  - be->send() removed (solely using be->plugin->send())
  - be_getID() and be_getTID() removed
  - peer_getID(), peer_getTID() and peer_getByID() removed
  - PSI_PROTO_ macros completely removed
  - psi_net_t->status field removed
  - removed PSI_DEFAULT_QUEUE macro
- recent API additions:
  + peer_connect() and peer_connect2()
  + peer_service() and peer_service2()
  + peer_query_info()
  + peer_refresh_info_cache()
  + peer_get_sender()
  + be_is_null()
  + be_signal_*()
  + peer_signal_*()
  + be_signal_*()
  + sbe_init()
  + sbe_connect()
  + sbe_accept()
  + sbe_dispatch()
  + sbe_send()
  + mtx_pool_*()
  

Changes between 0.5 and 0.6 (released 12-01-2005)
- depends on PSIutil 1.4
- fixed performance regression: a nanosleep call was forgotten in a loop.
- files.h added: it contains macros for files and paths 
- added -fvisibility=hidden flag. This causes no function to be exported, 
  unless API functions are marked with the 'export' attribute. This
  pseudo-keyword is defined as __attribute__((visibility("default"))).
  This flag is placed into the PICFLAG in makefactory/CC by default. 
- some code/API cleanup: private/protected/public scheme from OOP-languages
  adapted into code. Not all files have been updated yet, however, the most
  important ones are. 
- PSI_PROTO_* macros removed from typedef.h. Each backend has to define its 
  own (unique) PSI_PROTO_* macro
- added Uniform Resource Identifier (puri.c/puri.h). These uniquely identify
  any object within the network
- added req_id field into networking packets (chunks):
  o PSI_MODE_NEGOTIATE indicates, whether this field is used.
  o a message can now request an answer
  o maximum number of pending messages is set to 65536
  o static negotiation now implemented with this field. The API, however, 
    might change when generic, adaptive negotiation is fully implemented
- socket.[ch] added: 
  o several functions moved from backend.[ch] and recv_packet.[ch]
  o recv_packet.[ch] removed. 
  o generic backend constructors/destructors added to the plugin structure
  o all socket backends (TCP, UNIX, ...) should inherit from socket.[ch]
- null_recv_fn() and null_send_fn() set be->send()/be->recv()
- be->msgQueue removed
- removed deprecated and (currently) unused params/options stuff. These
  mechanisms will be reintroduced later again
- changed buffer handling:
  o buffer adjustment on runtime is now forbidden (this deprecates
    peer->set.mss)
  o be->recv_buf was replaced by a struct 'rBuf' containing a data, size and 
    destr field (similar to chunk_t).
  o listeners do not need a buffer
  o be_connect_*() and be_listen_*() functions now may be called with a static
    buffer as be argument.
- added more logging verbosity. psi_showStats(), be_showStats(), peer_echo() 
  and be_echo() added
- psi_strm_to_uintX() and psi_uintX_to_strm() macros added for portable 
  integer network type conversion
- API changes:
  o createPeer()       -> peer_create()
  o shutdownPeer()     -> peer_cleanup()
  o psi_getPeer[T]ID() -> peer_get[T]ID()
  o psi_getPeerByNum() -> peer_getByID()
  o psi_showStats      -> peer_showStats()
  o be_connect()       -> (removed)
  o be_listen()        -> (removed)
  o psi_getBE          -> be_getByID()  (moved from peer.[ch] to backend.[ch])
  o PURI functions added: puri_parse(), puri_assemble() and puri_free()
  o directory backend functions: be_{listen|connect}_dir[_va]()
  o null backend functions: _{listen|connect}_null[_va]()
  o various changes in backend API (see above: buffer handling, socket_be_t)
  o export keyword (see above)
  o removed all remaining inline attributes from API calls
  o added psi_strm_to_uintX() macros replacing memcpy (see above)
  o accordingly added psi_uintX_to_strm() macros
  o be_setEstablish_fn() added.
- major updates to backend handling methods:
  o Now any new protocol or backend type needs to implement certain set of 
    methods, and return a handle associated to a certain protocol number
  o null_plugin added (PSI_PROTO_NULL)
  o file access backend type added. This enables local directory operations
    available with PSI_PROTO_DIR backends. This backend is yet incomplete due
    to missing routing/forwarding and negotiation capabilities.

Changes between 0.4 and 0.5 (released 26-09-2004)
- depends on PSIutil 1.3.1 or higher
- bigPackets completely removed and replaced by a general receive method.
  See be_recv(). Also, chunk maximum size has been raised to 4 GB.
- packet_t struct completely removed
- rewritten negotiate / packetfilter mechanism
- per packet compression now works
- enable more 'debugging' : psi_showStats() dumps everything regarding a 
  connection (backend)
- event callbacks recvFilter (now pipeline) and negotiate are now implemented
  per backend instead of per peer
- raw (TCP) send/recv mode (PSI_MODE_RAW) (overrides the PSInet protocol)
- PSIutil : user/password management integration
- PSIworld : much improved Makesystem
- peer->backends.primary and psi_set_primary() removed, though they 
  were unneeded
- chunk_t* cloneChunk(chunk_t* src, chunk_t* dest) API call: 
  makes a deep-copy of a chunk. If cnk->destr() is psi_free(), 
  set it to psi_dont_free().
- cnk->destr() prototype changed from (*)(void*) to (*)(void*,uint).
- PSIutil : base64 converted passwords. Note: authentication is yet
  deactivated
- added Unix Domain Protocol support (PSI_PROTO_UNIX)
- unified (thus heavily changed) backend model:
  o psi_connect()/psi_listen() API calls changed
  o psi_activate_be() call added: it takes an abstract psi_conn_t handle
    and plugs a backend onto a peer.
  o thread handling changed: Unix Domain Protocol and probably others 
    don't need a listening thread. This case is handled by the existance
    of a psi_conn_t->thread() function.
- psi_net_com_t struct dropped. we solely use psi_net_t structs for peer and 
  CI representation.
- peer numbering scheme added:
  o for every peer, the numbering '<CI> : <backend>' will be used,
    where '0 : <backend>' represents all backends of the peer itself.
  o psi_getID() API call returns backend ID. 
  o psi_getPeerID() call returns 0 or the client instance ID if an owner
    exists. 
  o be_echo() call added.
- makefactory/include/portable.h dropped for now.
- peer/backend shutdown tweaked
- detach_thread() call added
- lots of gdb/valgrind failures and warnings removed
- all <stdint.h> includes were replaced by <inttypes.h>
- netConsole testing console much improved. 

Changes between 0.3 and 0.4 (released 15-03-2004) 
- frontend API/model changes: we no longer have explicite server or clients,
  but rather 'peer' communication to each other. each peer can have 
  backends (listener, sender, receiver) connected , which act autonomously
  within a peer
- debugging console added (PSIutil/console)
- threads now properly spawn and join
- receive process rewritten: receiver now acts blocking in an own thread
- removed some unneeded struct fields, i.e rcvQueue in server/client
  structs wasn't needed anymore
- 2004 copyright added
- examples in test/PSInet now use sigaction instead of signal. they also make
  "green" debug output
- simple authentification model implemented (PSIutil/auth)
- almost complete backend rewrite
- backend API/model changes: now a connection object is created, then
  a number of connections can be plugged into it.
- backend test for tcp added (needs updating)