Defined in 2 files as a macro:

• include/uapi/linux/tcp.h, line 105 (as a macro)
• tools/include/uapi/linux/tcp.h, line 102 (as a macro)

Referenced in 5 files:

• net/ipv4/tcp.c, line 4540
• net/mptcp/sockopt.c, line 1419
• tools/testing/selftests/bpf/prog_tests/tcp_rtt.c, line 34
• tools/testing/selftests/net/tcp_ao/lib/repair.c, line 77
• tools/testing/selftests/net/tcp_mmap.c, line 161