pppoehdr
struct pppoehdr *ph;
ph = (struct pppoehdr *)(mtod(n, caddr_t) + noff);
#define PPPOE_HEADERLEN sizeof(struct pppoehdr)
struct pppoehdr *ph;
ph = (struct pppoehdr *)(eh + 1);
struct pppoehdr *ph;
ph = mtod(m, struct pppoehdr *);