Write an Android application

Write from GNU source like SIPDROID (Java source ) and/or SIPHON ( C source ) projects a dedicated app following these requirements: a) You can use GNU SIPDROID and SIPHON sources available on the internet b) App will do VoIP calls c) As default voIP provider will be placed with default configuration to avoid configuration requirements from users d) First SIP REGISTER message MUST contents some credentials as encoded IMEI and user phone number to provide back from our registration servers the first credentials e) Protocol must be SIPv2. TLS must be supported if available on our connection servers to encrypt registering communications. SRTP is not full required f) APP must be runs on Android, Symbian and IOS g) Codec g729 must be supported h) Preferable programming in C ( avoid Java as much as possible ) as will help you to implement other voice codecs. i) SIP Provider logo will be provide to show at startup the application j) App must be configurable to use WiFi and/or GPRS/3G/4G networks k) Dial pattern may be any E164 number as well as name@location ( standar SIP To: fields ) and our server will separate the path if calling party is a phone or is a voIP client even from other networks ( i.e. Gtalk, Skype, etc ) l) Dialed number may be fetched from local phone directory m) app must be always running on the phone, as daemon, in a way incoming calls can be delivered to the user ( like whatsapp, Skype, Sipdroid, Viber, Siphon do )