Hi Walter,
thanks for email.
First I want to see if there is some difference between the new function
you add and the already existing function add_rcv_param().
http://openser.org/docs/modules/1.0.x/nathelper.html#AEN331
Regards,
Bogdan
Walter Schober wrote:
Hi!
Maybe someone find's that useful. It's nearly the same than mangler,
but the difference is, that it stores the old values, too.
Short description: nathelper stores original contact + addr:port from
where the request was received and puts itself in the list to register
a client on the next proxy. Keepalive has to be done by other methods.
See details in attached readme.
/Walter
------------------------------------------------------------------------
Nathelper Patch for registering on remote proxies
-------------------------------------------------
V 0.2
20060212
WSC [EMAIL PROTECTED]
-------------------------------------------------
Description: Openser is placed in front of another proxy not supporting RFC
3327 (Patch Header Support).
Using module nathelper the OpenSER detects nated clients and modifies the Contact field of the register.
The Contact header is expanded by a new "route", which is substituted instead of the IP:Port the
register is received from.
The operation is done after fixing the Contact in
fix_nated_contact();
Original fix_nated_contact() just replaces the host:port with host:port from where the request was
received from.
If the module parameter "contact_expander" is set, this value is inserted behind the user@ replacing the
fixed original host port.
e.g. original Contact is
Contact: <sip:[EMAIL PROTECTED]:5555;some-uri-param>;additional-params
the fix_nated_contact() replaces that with the IP from where the request was
received from:
Contact: <sip:[EMAIL PROTECTED]:port;some-uri-param>;additional-params
If contact_expander is set, this string is inserted as
Contact: <sip:[EMAIL
PROTECTED];x-orig=some_ip:port;x-orig-nat=original-contact;some-uri-param>;additional-params
e.g. contact_exander = 1.2.3.4:5066, resulting in
Contact: <sip:[EMAIL
PROTECTED]:5066;x-orig=33.44.55.66:5066;x-orig-nat=192.168.1.1:5062;some-uri-param>;additional-params
A Invite to such a contact results in
INVITE sip:[EMAIL PROTECTED]:5066;x-orig=33.44.55.66:5066;x-orig-nat=192.168.1.1:5062;some-uri-param
which could be replaced by e.g. textops and avp_ops
avp_write("$ruri","$x-orig");
if (subst_uri('/^sip:(.+)@.*;x-orig-nat=(.*)$/sip:[EMAIL PROTECTED]/i'))
{
avp_subst("$x-orig","/^(.*)@.*;x-orig=(.*);x-orig-nat=.*$/[EMAIL
PROTECTED]/");
avp_pushto("$duri","$x-orig");
route(1);
forwarding to the original contact address, but to NATed contact address.
New Module Param:
--------------------------------------------------
modparam("nathelper", "contact_expander", "1.2.3.4:5066")
New Function Call:
--------------------------------------------------
None.
Example:
--------------------------------------------------
# add myself as an alias
alias=1.2.3.4:5066
# set contact_expander to myself
modparam("nathelper", "contact_expander", "1.2.3.4:5066")
# avpops
modparam("avpops", "avp_aliases", "x-orig=i:32")
# is request is directed to me
if (uri==myself) {
# check, if we have to restore old destination
avp_write("$ruri","$x-orig");
if (subst_uri('/^sip:(.+)@.*;x-orig-nat=(.*)$/sip:[EMAIL PROTECTED]/i'))
{
avp_subst("$x-orig","/^(.*)@.*;x-orig=(.*);x-orig-nat=.*$/[EMAIL
PROTECTED]/");
avp_pushto("$duri","$x-orig");
# forwared to destination
route(1);
return;
}
}
# ... do something ...
# fix the Register as usual
if (method=="REGISTER" || method=="INVITE" || method=="REFER") {
if (nat_uac_test("18")) {
fix_nated_contact();
force_rport();
append_hf("P-hint: nathelper applied\r\n");
} else {
append_hf("P-hint: nathelper not applied\r\n");
};
};
# ... continue ... do something with the request
Installation
----------------------------------------------------
Patch the nathelper.c located in modules/nathelper executing
cp nathelper.c nathelper.c.orig
patch nathelper.c <nathelper.patch
Rebuild module nathelper
make modules=modules/nathelper modules
make install
The patch is based on OpenSER 1.0.0.
Changes are in function fix_nated_contact_f() only + parameter definitions.
Restart OpenSER.
-----------------------------------------------------
New function fix_nated_contact_f():
static int
fix_nated_contact_f(struct sip_msg* msg, char* str1, char* str2)
{
int offset, len, len1;
char *cp, *buf, temp[2];
contact_t *c;
struct lump *anchor;
struct sip_uri uri;
str hostport;
if (get_contact_uri(msg, &uri, &c) == -1)
return -1;
if ((c->uri.s < msg->buf) || (c->uri.s > (msg->buf + msg->len))) {
LOG(L_ERR, "ERROR: you can't call fix_nated_contact twice, "
"check your config!\n");
return -1;
}
offset = c->uri.s - msg->buf;
anchor = del_lump(msg, offset, c->uri.len, HDR_CONTACT_T);
if (anchor == 0)
return -1;
hostport = uri.host;
if (uri.port.len > 0)
hostport.len = uri.port.s + uri.port.len - uri.host.s;
cp = ip_addr2a(&msg->rcv.src_ip);
len = c->uri.len + strlen(cp) + 6 /* :port */ - hostport.len + 1;
if (contact_expander.len) {
LOG(L_DBG, "Expanding Contact: %s\n", contact_expander.s);
len += contact_expander.len + hostport.len + 20;
}
buf = pkg_malloc(len);
if (buf == NULL) {
LOG(L_ERR, "ERROR: fix_nated_contact: out of memory\n");
return -1;
}
temp[0] = hostport.s[0];
temp[1] = c->uri.s[c->uri.len];
c->uri.s[c->uri.len] = hostport.s[0] = '\0';
if (contact_expander.len) {
// sip:user:[EMAIL PROTECTED]:port ->
// sip:user:[EMAIL
PROTECTED]:PORT;x-orig=host:port;x-orig-nat=priv-host:priv-port
len1 = snprintf(buf, len, "%s%s;x-orig=%s:%d;x-orig-nat=%c%s",
c->uri.s,
contact_expander.s,
cp, msg->rcv.src_port,
temp[0],
hostport.s + 1);
} else {
len1 = snprintf(buf, len, "%s%s:%d%s", c->uri.s, cp,
msg->rcv.src_port,
hostport.s + hostport.len);
}
if (len1 < len)
len = len1;
hostport.s[0] = temp[0];
c->uri.s[c->uri.len] = temp[1];
if (insert_new_lump_after(anchor, buf, len, HDR_CONTACT_T) == 0) {
pkg_free(buf);
return -1;
}
c->uri.s = buf;
c->uri.len = len;
return 1;
}
------------------------------------------------------------------------
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