Network　function　virtualization　allows　network　functions　to　be　implemented　and　managed　flexibly　as　a　service　function　chain　(SFC)　in　the　data　plane　to　process　flows.　However,　software-based　SFCs　lead　to　poor　performance　compared　to　proprietary　middleboxes.　Moreover,　existing　solutions　tackling　performance　issues　suffer　from　the　development　complexity　incurred　by　hardware　details.　To　address　these　problems,　we　leverage　both　the　high　performance　of　P4-capable　devices　and　the　high　flexibility　of　P4　language.　In　this　paper,　we　present　a　P4　Service　Chaining　framework　(P4SC),　which　tackles　multiple　challenges　for　P4　to　support　the　SFC　implementation.　P4SC　provides　a　suite　of　primitives　allowing　efficient　SFC　expression,　and　a　converter　and　a　generator　converting　input　SFC　requests　to　the　corresponding　P4　program.　Here,　an　algorithm　based　on　longest　common　subsequence　(LCS)　is　used　to　allow　simultaneously　implementing　multiple　SFCs.　Moreover,　P4SC　offers　a　runtime　manager　for　flexible　SFC　management　at　runtime.　It　also　provides　an　automatic　integration　mechanism　to　integrate　P4-based　NFs　into　P4SC.　We　implement　a　P4SC　prototype,　which　supports　three　types　of　P4-capable　devices.　The　experimental　results　show　that　P4SC　outperforms　state　of　the　arts　with　orders-of-magnitude　SFC　performance　improvement　while　maintains　high　flexibility.