Defined in 2 files as a macro:

• bsd/net/if_types.h, line 131 (as a macro)
• bsd/net/if_types.h, line 142 (as a macro)

Referenced in 5 files:

• bsd/netinet/in_pcb.c, line 1337
• bsd/netinet/ip_icmp.c, line 354
• bsd/netinet/ip_input.c, line 976
• bsd/netinet6/in6.c, line 2661
• bsd/netinet6/ip6_input.c, line 732