GRE_IS_CSUM - Linux

Symbol: GRE_IS_CSUM

drivers/net/ppp/pptp.c

GRE_IS_CSUM(header->gre_hd.flags) || /* flag CSUM should be clear */

tools/testing/selftests/bpf/progs/bpf_flow.c

if (GRE_IS_CSUM(gre->flags))