Ok, here are the same structs in the engine source:

Code:
typedef struct BSP_LEAF {
	int   type;
	int   nRenderFrame;	// was leaf already rendered?
	float minmaxs[6]; // bounding box
	BSP_NODE  *parent;
	byte  *PVS;
	BSP_SURFACE **surfacelist;
	int   numSurfaces;
	int   nLeaf;
} BSP_LEAF;

typedef struct BSP_NODE {
	int   type;
	int   nRenderFrame;	// was node already rendered?
	float minmaxs[6]; // bounding box
	BSP_NODE  *parent;
	BSP_PLANE *plane;
	BSP_NODE  *child[2];
	int   nSurface;
	int   numSurfaces;
} BSP_NODE;