= SSL/TLS on Symbian =
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PJSIP provides secure communications via secure socket abstraction, {{{pj_ssl_sock_*}}}, which can be used by the higher level applications, such as SSL/TLS SIP transport to perform secure SIP signaling. On Symbian platforms, the secure socket implementation is done natively using {{{CSecureSocket}}} class. This feature is available from version 1.5 onwards.

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== Scope ==
Secure socket implementation on Symbian provides:
 1. Transparent SSL/TLS operations, application uses the secure socket basically the same way as using normal socket, e.g: when connection completion status is reported (via callback) as successful, it means that both the underlying socket connection and the SSL/TLS handshake are successful.
 1. Active socket operations as provided by [[http://www.pjsip.org/pjlib/docs/html/group__PJ__ACTIVESOCK.htm Active Socket I/O]].
 1. List of trusted Certificate Authorities (CA) is based on Symbian Certificate Management, e.g: in E65, Main Menu > Tools > Settings > Security > Certificates Management.
 1. Support for SSL 3.0 and TLS 1.0.

== Limitations ==
 1. Only support for client mode ({{{CSecureSocket}}} limitation).
 1. Specifying client credential (e.g: certificate and the corresponding private key) is not supported ({{{CSecureSocket}}} limitation), so secure socket may not be able to connect to server that requires client certificate.
 1. Currently, server certificate verification is only done internally by {{{CSecureSocket}}}, further verification mechanism by application (e.g: via callback) is not supported. '''Note''' that untrusted server certificates result in a user dialog.
 1. Managing (adding/editing/deleting) entry of trusted CA list should be handled by application.

== Enable SIP transport SSL/TLS on {{{symbian_ua}}} sample application ==
 1. Enable TLS as described [wiki:TLS#BuildPJSIPwithTLSSupport here].
 1. Modify transport setting in {{{ua.cpp}}}:
{{{
#define ENABLE_SIP_TLS	1 // default is 0
}}}
 1. You have to set the SSL/TLS server name field accordingly, otherwise the connection will either fail with !KErrAbort/Interrupted or a warning dialog about different server name will be displayed:
{{{
#define TLS_SRV_NAME	"pjsip.org"
}}}
 1. Update other related configurations {{{ua.cpp}}} such as SIP account, e.g:
{{{
#define HAS_SIP_ACCOUNT	1
#define SIP_DOMAIN	"your_domain/realm"
#define SIP_USER	"your_userid"
#define SIP_PASSWD	"your_pass"
#define SIP_PROXY	"<sip:some_proxy;transport=tls;lr>"
}}}
'''Note''' that without registering an account into a registrar, symbian_ua will not be able to be contacted (e.g: receive calls), as the secure socket backend ({{{CSecureSocket}}}) can only work as client.
 1. If you don't use SIP account (for example for quick testing only), don't forget to add ";transport=tls" parameter to your destination URI, e.g.:
{{{
#define SIP_DST_URI	"<sip:100@pjsip.org;transport=tls>"
}}}


== Building your own application using SSL/TLS on Symbian ==
 1. Enable TLS as described [wiki:TLS#BuildPJSIPwithTLSSupport here].
 1. If the '''low level''' secure socket is needed, include {{{ssl_sock.h}}}:
{{{
#include<pj/ssl_sock.h>
}}}
 1. When '''using PJSUA-LIB''', SIP transport TLS can be enabled by instantiating SIP transport type {{{PJSIP_TRANSPORT_TLS}}}, e.g (captured from symbian_ua {{{ua.cpp}}}):
{{{
pjsua_transport_config tcfg;
pjsua_transport_id tid;

pjsua_transport_config_default(&tcfg);
tcfg.port = SIP_PORT;
tcfg.tls_setting.server_name = pj_str(TLS_SRV_NAME);
status = pjsua_transport_create(PJSIP_TRANSPORT_TLS, &tcfg, &tid);

// then, specify "transport=tls" URI param in the proxy/registrar URI,
// e.g: "<sip:some_proxy;transport=tls>"
}}}
 1. '''Link''' the application to {{{securesocket.lib}}}, by specifying the library in the application MMP:
{{{
LIBRARY securesocket.lib 
}}}

== Troubleshooting ==

=== Error -7547 ===
{{{
 08:10:30.853    pjsua_acc.c  Registration sent
 08:10:32.279 tlsc0x2432b71c  TLS connect() error: Symbian native error -7547 [code=127547]
 08:10:32.294  tsx0x243184b8  Failed to send Request msg REGISTER/cseq=38313 (tdta0x24328cf0)! err=127547 (Symbian native error -7547)
 08:10:32.304    pjsua_acc.c  SIP registration failed, status=503 (Symbian native error -7547)
 08:10:32.314 symbian_ua.cpp  Registration failed!
 08:10:32.431 tlsc0x2432b71c  TLS transport destroyed with reason 127547: Symbian native error -7547
}}}
Symbian error -7547 is about set setOpt.
Check the source code, you have to define servername.

=== Error KErrAborted / Interrupted ===

You need to set the servername field.