NATT Keepalive RIL Implementation

RIL support for startKeepalive and stopKeepalive

Bug: 63942305
Test: vts
Merged-In: Ie4ad70b0120d234fc976a9e24e244c8bd9b08bfb
Change-Id: Ie4ad70b0120d234fc976a9e24e244c8bd9b08bfb
3 files changed
tree: 9d0248d8569133a466b78bc75ccd0479ba0cf948
  1. include/
  2. libril/
  3. librilutils/
  4. reference-ril/
  5. rild/
  6. CleanSpec.mk