Internal job.. India and Modi have gained a lot:
1 - In the middle of negotiations between Taliban and US, when India was sidelined however it was pushing its own standpoint that Taliban will help Kashmiris when US will leave.. This standpoint will gain weight now and in the final agreement, US will try to get Taliban's agreement that they will not help independence movement in Kashmir and also will not destroy Indian investments in the region.
2 - Modi will get a chance to repeat another fake surgical strike before next elections.. this will get him enough public support to win the PM seat again.
3 - Modi will create a war like situation on both LoC and International Border to shatter investor's confidence.
4 - Kashmiri freedom struggle will get a blow in UN and pressure will be increased on China to not veto any resolution put forth against Hafiz Saeed.
5 - Overall, it will hurt Pakistan much more and India will get enough benefit out of this false flag attack.. of course, it was designed to get India all the benefits, not Pakistan..