Release notes for SIP Express Router (ser)

***********************************************

$Id: NEWS 166 2007-03-02 19:28:23Z vingarzan $

0.10.99-dev changes

new archs:

modules:

- tls - new module that enables tls support (set enable_tls=yes

in the config file and load the tls module)

- ctl - new fifo/unixsocket/xmlrpc like module, using a space

efficient binary encoding for the requests.

It supports multiple clients on tcp, udp, unix stream or

unix datagram modes. By default (no modparams) it opens

one unix stream control socket in /tmp/ser_ctl.

It also includes extended fifo support: multiple fifos,

fifo over tcp, udp and unix sockets (see ctl/ctl.cfg).

Use utils/sercmd/sercmd to send commands to it.

- dispatcher - added hashing after request uri and to uri

- added a new flag parameter which can be used (for now) to

select only the username or the username, host and port when

hashing after an uri (to, from or request uri)

- improved uri hashing (password is ignored, port is used only

if != 5060 or 5061)

- tm - aggregate challenges (WWW/Proxy-Authenticate) from all the

401 & 407 if the final reply is a 401/407. To turn this off

and fall back to the old behaviour set tm aggregate_challenges

parameter to 0.

- if a relayed 503 is the final reply, replace it by a 500

- if a 503 reply is received try the dns based failover

(forward to another ip if the original destination uri

resolved to several SRV, A or AAAA records)

- on 6xx immediately cancel all the branches for which a

provisional response was received and wait for all the

branches to finish (either timeout, the 487 from the CANCEL

or a final response still on the wire in the moment the

CANCEL was sent)

- better final reply selection: 6xx is preferred over other

negative replies; from several 4xx prefer 401, 407, 415, 420,

484 (in this order). For all the other cases, return the lowest

code (as before)

- special functions for checking for timeout, if a reply was

received or if the current transaction was canceled

- dns failover and dst blacklist support

- migrated to the new timers (tm timers completely rewritten)

- improved speed and less memory usage

- much more precise retransmissions timing

- params: - retr_timer1p1, retr_timer1p2, retr_timer1p3 removed

and replaced by retr_timer1 and retr_timer2

- all timer values are now expressed in milliseconds

(they were in seconds before).

Affected params: fr_timer, fr_inv_timer, wt_timer,

delete_timer, retr_timer1, retr_timer2

- retr_timer1 (first retransmission) changed to 500 ms

- delete_timer changed to 200 ms

- unix_tx_timeout expressed now in milliseconds; default

value changed to 500 ms

- functions:

- t_branch_timeout() -- returns true if the failure

route is executed for a branch that did timeout

(failure_route only).

- t_branch_replied() -- returns true if the failure

route is executed for a branch that did receive at

least one reply in the past (the current reply

is not taken into account). It can be used

together with t_branch_timeout() to distinguish

between a remote side that doesn't respond (some

provisional reply received) and one that is completely

dead. (failure_route only)

- t_any_timeout() -- returns true if any of the current

transaction branches did timeout.

- t_any_replied() -- returns true if at least one branch

of the current transaction received one reply in the

past. If called from a failure_route or an

onreply_route, the "current" reply is not taken into

account.

- t_is_canceled() -- returns true if the current

transaction has been canceled.

- new t_set_fr(timeout_fr_inv, timeout_fr) -- allows

changing the transaction timer from script, even if

the transaction was already created (see tm docs for

more).

- t_relay will not stop script execution anymore in case of

send error

- textops - search() can be used in the onsend_route where it will search

on the "new" message (after applying all script changes, adding

Vias a.s.o) and not on the original message

core:

- compiled by default with tls hooks support (so that no recompile is

needed before loading the tls module and enabling the tls support)

- enable_tls config option added (the reverse of disable_tls)

- added STUN keep-alive functionality in accordance with

draft-ietf-behave-rfc3489bis-04.txt

- dns cache and dns failover support added (see doc/dns.txt)

- destination blacklist added -- destinations to which forwarding fails

(send error, tm timeout a.s.o) are temporarily added to a blacklist which

is consulted before each send => faster send error detection

in the near future (see doc/dst_blacklist.txt)

- default log level switched to 0 (only messages < L_WARN will be printed

by default)

- separate memdbg log level which controls the memory/malloc related

debug messages (to see them ser must be compiled with malloc debuging:

-DDBG_QM_MALLOC or -DDBG_FM_MALLOC and memdbg must be <= debug )

- added named routes: names can be used instead of numbers in all the

route commads or route declarations. route(number) is equivalent to

route("number").

Example:

route("test");

route["test"]{

...

}

- added named flags, declared at the beginning of the config file with:

flags flag1_name[:position], flag2_name ...

Example:

flags test, a:1, b:2 ;

route{

setflag(test);

if (isflagset(a)){ # equiv. to isflagset(1)

....

}

resetflag(b); # equiv. to resetflag(2)

- added return [val] which returns from a route. if no value is specified, or

a route reaches its end without executing a return statement, it returns 1.

If return is used in the top level route is equivalent with exit [val].

- drop /exit [n] now will end the script execution

exit n will exit with code n (usefull in onreply/onsend routes where

if script code !=0 a reply is generated/the message is sent or to force

script errors)

- added $? which can be used to check the return code of the last executed

route{} (e.g. route(1); if ($?==1){ /* ... */}else if ($?==2) ... )

- onsend_route added: special route executed before a request is sent.

Only a limited number of commands are allowed (drop, if

+ all the checks, msg flag manipulations, send(), log(),

textops::search()). In this route the final destination

of the message is available an can be checked (with

snd_ip, snd_port, to_ip, to_port, snd_proto, snd_af).

This route is executed only when forwarding requests.

It's not executed for replies, retransmissions, or

locally generated messages (e.g. via fifo uac).

short example:

onsend_route{ if(to_ip==1.2.3.4 && !isflagset(12)){

log(1, "message blocked\n");

drop;

}

}

- onsend_route specific checks:

- snd_ip, snd_port - behave like src_ip/src_port, but contain the

ip/port ser will use to send the message

- to_ip, to_port - like above, but contain the ip/port the message will

be sent to (not to be confused with dst_ip/dst-port, which are the

destination of the original message: ser's ip and port on which the

message was received)

- snd_proto, snd_af - behave like proto/af but contain the

protocol/address family that ser will use to send the message

- msg:len - when used in an onsend_route, msg:len will contain the length

of the message on the wire (after all the changes in the script are

applied, Vias are added a.s.o) and not the lentgh of the original

message

- timer: - improved performance/precision, new api, see doc/timers.txt

- tcp: - improved performance (io event handling), using OS specific

optimizations

- 1024 connections limit removed (see tcp_max_connections)

- resolver: - timeouts, retries a.s.o can now be set from ser.cfg

(see below dns_* and man resolv.conf(6)).

The maximum time a dns request can take (before failing) is:

(dns_retr_time*dns_retr_no)*(search_list_domains)

If dns_try_ipv6 is yes, mutliply it again by 2.

The fastest possible dns config (max 1s):

dns_try_ipv6=no

dns_retr_time=1

dns_retr_no=1

dns_use_search_list=no

- default on reply route added: onreply_route {.. } will add a default

onreply route that will be executed for any reply (usefull to catch

replies without using tm)

- branch_routes added (tm triggered), only a very limited number of commands

are available (see tm docs)

- avps directly accessible from script with %avp_name (variable style)

new config variables:

enable_tls/disable_tls = enable/disable tls support, default disable.

Note: a tls "engine" is still needed (e.g. the tls module must

be loaded, enable_tls by itself is not enough).

exit_timeout = seconds - how much time ser will wait for all the shutdown

procedures to complete. If this time is exceeded, all the remaining

processes are immediately killed and ser exits immediately (it might

also generate a core dump if the cleanup part takes too long).

Default: 60 s. Use 0 to disable.

stun_refresh_interval = number in millisecond (default 0); value for

attribute REFRESH INTERVAL

stun_allow_stun = 0 | 1 (off | on - default 1); use STUN or not if compiled

stun_allow_fp = 0 | 1 (off | on - default 1); use FINGERPRINT attribute

use_dns_cache = on | off (default on)

use_dns_failover = on | off (default off)

dns_cache_flags = number (default 0)

dns_cache_negative_ttl = number in seconds (default 60)

dns_cache_min_ttl = time in seconds (default 0)

dns_cache_max_ttl = time in seconds (default MAXINT)

dns_cache_mem = maximum memory used for the dns cache in Kb (default 500 K)

dns_cache_gc_interval = interval in seconds after which the dns cache is

garbage collected (default: 120 s)

use_dst_blacklist = on | off (default off)

dst_blacklist_expire = time in s (default 60)

dst_blacklist_mem = maximum memory used for the blacklist in Kb (default 250

K)

dst_blacklist_gc_interval = interval in seconds after which the destination

blacklist is garbage collected (default 60)

tos = number - ip type of service (TOS) value

dns_try_ipv6 = yes/no - if yes and a dns lookup fails, it will retry it

for ipv6 (AAAA record). Default: yes

dns_retr_time = time - time in s before retrying a dns request.

Default: system specific, depends also on the/etc/resolv.conf content

(usually 5s).

dns_retr_no = no. - number of dns retransmissions before giving up.

Default: see above (usually 4)

dns_servers_no = no. - how many dns servers from the ones defined in

/etc/resolv.conf will be used. Default: all of them.

dns_use_search_list= yes/no - if no, the search list in /etc/resolv.conf

will be ignored (=> fewer lookups => gives up faster). Default: yes.

HINT: even if you don't have a search list defined, setting this option

to "no" will still be "faster", because an empty search list is in

fact search "" (so even if the search list is empty/missing there will

still be 2 dns queries, eg. foo+'.' and foo+""+'.')

tcp_connection_lifetime = value (s) - how long the lifetime of a

tcp connection will be exteneded after an IO event (accept, connect,

read, write). Default: 120 s.

tcp_poll_method = poll|select|epoll_et|epoll-lt|kqueue|devpoll - poll

method used (by default the best one for the current OS is selected)

tcp_max_connections = no. - maximum number of tcp connections (if the number

is exceeded no new tcp connections will be accepted). Default: 2048.

tools:

utils/sercmd - command line serctl like tool for interrogating ser ctl

module (uses the binrpc encoding). Supports various

connection methods (udp, tcp, unix stream & datagram sockets),

reply formating (see -f, e.g. sercmd -f "pid:%v %v\n" core.ps)

, interactive mode, command line completion (if compiled with

libreadline) a.s.o.

WARNING: - older 0.10.99-dev version (< 0.10.99-dev46) returned a 480 reply

on invite transaction timeout, if a provisional reply was received. Newer

versions reverted to returning 408 on all timeouts (one can use

t_branch_timeout() and t_branch_replied() to distinguish between the two

timeout types)

0.9.4 fixes/improvements (0.9.4 is a bug fix release for 0.9.3)

general:

- gcc 4.0 support

- mutlicast options are set for all the sockets

- mediaproxy: memory leak, unchecked memory allocations

- postgress: some bugs and cleanups (compiles cleanly now)

- tm: shm cloned lumps (SER-55)

- tm: t_fifo: 64-bit fix

- tm: dst_uri clone fix

- tm: t_newtran/t_restransmit* races (!)

- usloc: memory leak

solaris:

- serctl, better ISA detection, signals

*bsd:

- multicast options are properly set

openbsd:

- tcp 64 bit fix

0.9.3 changes

new archs:

- alpha experimental support

- mips2/cobalt experimental support

- x86_64 support

- OS X (darwin) support

- sparc32 single cpu highly experimental support

- ppc64 support

modules:

- enum - support for more than one NAPTR

- msilo - explicit multidomain support -- recipient's user ID is stored in

the columns username and domain -- r_uri column kept for compatibility

reasons (will be removed in future) but not filled by this version of

module

- mysql - implements a connection pool, all modules will use same connection

to access the database

- nathelper received port test (flag 16 for nat_uac_test): compares the

source port of the message with sip port in the first Via and returns

true if different.

- permsions - support for multiple allow/deny files, allow_register function

- TM has a new parameter: restart_fr_on_each_reply. If set (default)

fr_inv timer will be restarted for each provisional reply, if not set

it will be restarted only for the first reply and for replies >=180

(but only if increasing, eg.: 180, 181 ...). Usefull when dealing with bad

UAs that re-transmit 180s.

- TM saves the avp list into transactions, and make it available into

callbacks, failure and reply routes.

- TM contains new command - t_write_unix("/tmp/sems.sock", "announcement")

sends a message using unix socket interface instead of FIFO interface.

- TM contains new config variable - unix_tx_timeout -- it specifies the

transmit timeout of t_write_sock

- VM functionality was transfered into TM module. Instead of fetching the

email value from DB (as VM), TM looks for the "email" attribute to get the

value.

vm() function was replaced with t_write_req()

vm_reply() fifo functions was replcated by TM with t_reply() fifo function

NOTE!! because current version of SEMS/AA try to send reply via vm_reply,

it will not work with the TM version.

- xlog - printing the body of any header by specifying the name; new

specifiers for user-agent, message buffer, message length, message's flags,

message id.

new modules:

- avp / avp_db / avp_radius - load and check avps per caller or callee

- avpops - flexible module for operations with avps and database, introducing

a pseudo-varible support in SER configuration file

- cpl-c - implementation of Call Processing Language

- dispatcher - implements a dispatcher for incoming requests using hashes

over parts of the request to select the destination

- diversion - implements the Diversion extensions as per

draft-levy-sip-diversion-08

- flatstore - simple module that implements very fast inserts for accounting

purposes

- gflags - keeps a bitmap of flags in shared memory and may be used to change

behaviour of server based on value of the flags

- options - answer server options requests

- speeddial - provides on-server speed dial facilities

- uri_db - split from uri module, performs various checks related to SIP URI

over database fields

removed modules:

- vm - the functionality was transfered to tm module (see t_write_req(...)

method)

core:

- new parts:

UNIX domain socket server implemented

- changes:

- command line: removed -p port and extended -l:

-l [proto:]addr[:port] , where proto=udp|tcp and

addr= host|ip_address|interface_name. The format is the same

as for listen in the config file. ipv6 addresses must be enclosed in

[].

- added from_uri & to_uri: behave exactly like uri but use the

"From:"/"To:" uris

(e.g.: if (from_uri==myself) ..., if (to_uri=~"^sip:test@")... )

- config: better escape support in strings (e.g. \", \<cr>, \x0a, \012)

- bad network addresses are now automatically fixed

(e.g. 192.168.1.80/27 => 192.168.1.64/27)

- avp (Attribute-Value Pair) support added

- avp alias support added

- multicast support added (see mcast_loopback & mcast_ttl)

- saving of procces group id enabled, if the -G option is specified

(a safe way to quickly kill all ser processes)

- core dump-ing is enabled by default, see also disable_core_dump

- protocol and port can be specified in the alias and listen lines, e.g.:

alias= tcp:foo.bar:* udp:test.bar:5080 foo.com

listen= eth0 tcp:eth0:5065 udp:127.0.0.1 [3ffe::1]

- multiple operator support: ==, != for special operations (e.g myself, ip)

==, !=, ~= for strings

==, !=, >, <, >=, <= for integers

- database api changed to support usage of different drivers

simultaneously. The database URL must start now with the name of the

driver (module). Example: for mysql the DB URL

'sql://user:password@dbhost:port/database' must be specified now as

'mysql://user:password@dbhost:port/database'

- new config variables:

mcast_loopback = <yes/no> - loopback sent multicast datagram, default no.

mcast_ttl = number - set multicast ttl, default OS specific (usually 1).

sock_mode = <permissions> (e.g. sock_mode=0600: default value = 0660)

ser unix sockets and fifo will be created with this permissions

(old name fifo_mode is still supported, but deprecated)

sock_user = username|"uid"

sock_group = groupname|"gid"

change the owner and/or group of the ser unix sockets or fifo

Short example config snippet:

sock_mode=0600 # ser socket/fifo mode

sock_user="www-data" # ser socket/fifo owner

sock_group=nogroup

user=nobody # ser user (ser will suid to it)

disable_core_dump= yes|no

by default core dump limits are set to unlimited or a high enough

value, set this config variable o yes to disable core dump-ing

(will set core limits to 0)

open_files_limit= number

if set and bigger than the current open file limit, ser will try

to increase its open file limit to this number. Note: ser must be

started as root to be able to increase a limit past the hard limit

(which, for open files, is 1024 on most systems)

tcp_connect_timeout= seconds

time before an ongoing connect will be aborted

tcp_send_timeout= seconds

time after a tcp connection will be closed if it is not available

for writing in this interval (and ser wants to send something on it)

tcp_accept_aliases= yes|no

if a message received over a tcp connection has "alias" in its via

a new tcp alias port will be created for the connection the message

came from (the alias port will be set to the via one).

Based on draft-ietf-sip-connect-reuse-00.txt, but using only the port

(host aliases are too dangerous IMHO, involve extra DNS

lookups and the need for them is questionable)

See force_tcp_alias for more details.

log_facility = LOG_LOCAL0

if ser logs to syslog, you can control the facility for logging. Very

useful when you want to divert all ser logs to a different log file.

See man page syslog(3) for more detailes.

unix_sock = "/tmp/ser.sock"

The name of the socket the unixsock server should listen on.

unix_sock_children = 1

The number of children that will listen on the unix domain socket.

unix_tx_timeout = 2000

Timeout (in ms) used when sending replies through unix sockets.

- new script commands:

force_send_socket([proto:]address[:port])

sends the message from the specified socket (it _must_ be one of the

sockets ser listens on). If the protocol doesn't match (e.g. udp

message "forced" to a tcp socket) the closest socket of the same

protocol is used.

force_tcp_alias()

force_tcp_alias(port)

adds a tcp port alias for the current connection (if tcp).

Usefull if you want to send all the trafic to port_alias through

the same connection this request came from [it could help

for firewall or nat traversal].

With no parameters adds the port from the message via as the alias.

When the "aliased" connection is closed (e.g. it's idle for too

much time), all the port aliases are removed.

Note: by default ser closes idle connection after 3 minutes (stable)

or 1 minute (unstable) so to take full advantage of tcp aliases for

things like firewall and nat traversal, redefine TCP_CON_*TIMEOUT

in tcp_conn.h and recompile. Also right now there can be maximum

3 port aliases to a connection (you shouldn't need more than one).

To change this redefine TCP_CON_MAX_ALIASES in the same file

(set it to you desired value + 1; 1 is needed for the real port).

utilities:

- ngrep patch for displaying new lines in captured SIP messages is no longer

needed; use ngrep V 1.42 with the option "-W byline"

***********************************************

* Changes/fixes introduced in 0.8.12

***********************************************

+--------------------------------------------------------+

| WARNING: if you want to use a 0.8.11 config script |

| with 0.8.12, replace if ( len_gt(number) ) with: |

| if ( msg:len > bumber ) |

+--------------------------------------------------------+

New Features

============

texops:

- subst('s/re/repl/flags') support

core:

- added switch to check the config file (-c)

- changes: removed len_gt() and replaced with if (msg:len op number|max_len)

- multiple operator support: ==, != for special operations (e.g myself, ip)

==, !=, ~= for strings

==, !=, >, <, >=, <= for integers

- new config variables:

advertised_address= ip | string

address advertised in via and in the DST_* lumps (e.g RR)

This is the default value, if empty (default) the socket

address will be used.

WARNING: - don't set it unless you know what you are doing

(e.g. nat traversal)

- you can set anything here, no check is made

(e.g. foo.bar will be accepted even if

foo.bar doesn't exist)

advertised_port= no

port advertised in via and in the DST_*lumps (e.g. RR)

This is the default value, if empty (default) the socket

port will be used.

Same warnings as above.

- new script commands:

set_advertised_address(ip|string)

same as advertised_address but it affects only the current message:

Message host/lump address= the set_advertised one if

present, else advertised_address else socket address.

set_advertised_port(no)

same as advertised_port but it affects only the current

message; see set_advertised_address & s/address/port/g

usrloc:

- usernames are case insensitive

registrar:

- lookup function succeeds when appending of a branch failed

auth_db:

- support for rpid stored in database (thanks to Jakob Schlyter)

Bug fixes

=========

- memory leak in digest credentials parser fixed

- authenticathion ha1 didn't include domain if username was of the form

user@domain and calculate_ha1 was set to yes (modules/auth_db)

- tm reply processing race condition (modules/tm), special thanks go to

Dong Liu

- Many bugs in pa module fixed, works with registrar again.

Security updates

================

- fifo processing code will write responses only to other

fifos and only if they are not hard-linked, also default

ser fifo persmissions were changed to 0600.

Performance improvements

========================

- tuned internal malloc implementation parameters to better reflect the

actual workload (malloc is a little bit faster now)

***********************************************

* Changes introduced in 0.8.11

***********************************************

+--------------------------------------------------------+

| CAUTION: the 0.8.11 release include changes which |

| are incompatible with scripts and databases used |

| in previous versions. Care is advised when upgrading |

| from previous releases to 0.8.11. |

+--------------------------------------------------------+

New features

=============

- RFC3261 support

- TCP support and cross-transport forwarding [core]

- loose routing support [rr module]

- New modules

- vm -- voicemail interface [vm]

- ENUM support [enum]

- presence agent [pa]

- dynamic domain management -- allows to manipulate

hosting of multiple domains in run-time [module]

- flat-text-file database support [dbtext]

- rich access control lists [permissions]

- Feature Improvements

- click-to-dial, which is based on improved tm/FIFO

that better supports external applications [tm module]

- web accounting -- acc module can report to serweb

on placed calls [acc module]

- improved exec module (header fields passed now

as environment variables to scripts) [exec module]

- Architectural Improvements

- powerpc fast locking support

- netbsd support

- 64 bits arch. support (e.g. netbsd/sparc64).

- New Experimental Features (not tested at all yet)

- nathelper utility for Cisco/ATA NAT traversal [nathelper]

- another NAT traversal utility [mangler]

- postgress support [postgress]

- fcp module [fcp]

- pdt module (prefix2domain) [pdt]

Changes to use of ser scripts

=============================

About Multiple Transport Support

--------------------------------

SER now suports multiple transport protocols: UDP and TCP. As there

may be UAs which support only either protocol and cannot speak to

each other directly, we recommend to alway record-route SIP requests,

to keep the transport-translating SER in path. Also, if a destination

transport is not known, stateful forwarding is recommended -- use of

stateless forwarding for TCP2UDP would result in loss of reliability.

core

----

- reply_route has been renamed to failure_route -- the old name caused

too much confusion

- forward_tcp and forward_udp can force SER to forward via specific

transport protocol

acc module:

-----------

- radius and sql support integrated in this module; you need to

recompile to enable it

- acc_flag is now called log_flag to better reflect it relates

to the syslog mode (as opposed to sql/radius); for the same

reasons, the accounting action is now called "acc_log_request"

and the option for missed calls "log_missed_calls"

- log_fmt allows now to specify what will be printed to syslog

auth module:

------------

- auth module has been split in auth, auth_db, auth_radius, group

group_radius, uri and uri_radius

- all the parameters that were part of former auth module are now

part of auth_db module

- auth_db module contains all functions needed for database

authentication

- auth_radius contains functions needed for radius authentication

- group module contains group membership checking functions

- group_radius contains radius group membeship checking functions

- is_in_group has been renamed to is_user_in and places to groups

module

- check_to and check_from have been moved to the uri module

im module:

----------

- im is no longer used and has been obsoleted by TM

exec module:

------------

- exec_uri and exec_user have been obsoleted by exec_dset;

exec_dset is identical to exec_uri in capabilities; it

additionaly passes content of request elements (header

fields and URI parts) in environment variables; users of

exec_user can use exec_dset now and use the "URI_USER"

variable to learn user part of URI

- exec_dset and exec_msg return false, if return value of

script does not euqal zero

- exec_dset takes an additional parameter, which enables

validation of SIP URIs returned by external application

jabber module:

--------------

- presence support for Jabber users is enabled loading the PA

module and using handle_subscribe("jabber") for SUBSCRIBE

requests to jabber user

msilo module:

-------------

- m_store has now a parameter to set what should be considered

for storing as destination uri. This enables support for saving

the messages on negative replies.

radius_acc module:

------------------

- radius_acc module has been removed and radius accounting

is now part of acc module

registrar/usrloc modules:

-------------------------

- multi domain support, the modules user username@domain as AOR

if enabled

- descent modification time ordering of contacts

- case sensitive/insensitive comparison of URI can be enabled

rr module:

----------

- addRecordRoute has been replaced with record_route

- rewriteFromRoute has been replaced with loose_route()

- a new option, "enable_full_lr" can be set to make life

with misimplemented UAs easier and put LR in from "lr=on"

- rr module can insert two Record-Route header fields when

necesarry (disconnected networks, UDP->TCP and so on)

tm module:

----------

- t_reply_unsafe, used in former versions within reply_routes,

is deprecated; now t_reply is used from any places in script

- t_on_negative is renamed to t_on_failure -- the old name just

caused too much confusion

- FIFO t_uac used by some applications (like serweb) has been

replaced with t_uac_dlg (which allows easier use by dialog-

oriented applications, like click-to-dial)

- if you wish to do forward to another destination from

failure_route (reply_route formerly), you need to call t_relay

or t_relay_to explicitely now

- t_relay_to has been replaced with t_relay_to_udp and t_relay_to_tcp