Distributed　denial-of-service　(DDoS)　attacks　have　long　been　the　most　severe　and　destructive　attack　on　modern　networks.　Some　solutions　place　several　middleboxes　that　run　security-oriented　network　functions　(SNFs)　in　the　network　to　defend　against　DDoS　attacks.　However,　middleboxes　are　proprietary　and　fixed-function,　making　them　costly　and　inflexible　when　handling　attack　dynamics.　Another　class　of　solutions　exploits　the　capability　of　software-defined　networking　(SDN)　and　network　function　virtualization　(NFV)　to　run　virtualized　SNFs　on　commodity　servers.　This　reduces　the　cost　of　DDoS　attack　mitigation　while　enabling　high　flexibility　by　dynamically　removing　or　adding　SNF　instances.　However,　this　class　of　solutions　sacrifices　packet　processing　performance　and　incurs　non-trivial　end-to-end　latency,　which　is　unacceptable　for　many　latency-sensitive　internet　services.　Recently,　the　emergence　of　programmable　switches　brings　a　promising　alternative　solution:　arbitrary　SNFs　can　be　directly　performed　in　line-rate　ASIC　pipelines　of　programmable　switches,　enabling　low-cost,　flexible,　and　high-performance　DDoS　attack　mitigation.　In　this　article,　we　present　an　illustrative　survey　of　recent　solutions　that　leverage　programmable　switches　to　provide　DDoS　attack　mitigation.　Our　survey　can　help　understand　how　to　make　full　use　of　the　benefits　of　programmable　switches　to　defend　against　DDoS　attacks.