adjust_tcp_mss
m0 = adjust_tcp_mss(m0, session->peer_mru);
m0 = adjust_tcp_mss(m0, session->peer_mru);
struct mbuf *adjust_tcp_mss (struct mbuf *, int);
adjust_tcp_mss(pktp, lpktp, MRU_IPMTU(ppp->peer_mru));
adjust_tcp_mss(pktp, lpktp, MRU_IPMTU(ppp->peer_mru));
int adjust_tcp_mss(u_char *, int, int);