HelenOS sources

DHCP_LINK_ADD      70 uspace/lib/inet/src/dhcp.c 	errno_t rc = async_req_1_0(exch, DHCP_LINK_ADD, link_id);
DHCP_LINK_ADD     139 uspace/srv/net/dhcp/main.c 		case DHCP_LINK_ADD:
HelenOS homepage, sources at GitHub