m->m_len = sizeof (struct tcpiphdr);
#define xchg(a,b,type) { type t; t=a; a=b; b=t; }
xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, u_long);
xchg(ti->ti_dport, ti->ti_sport, u_short);
#undef xchg
m->m_len = sizeof (struct tcpiphdr);
#define xchg(a,b,type) { type t; t=a; a=b; b=t; }
xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, u_long);
xchg(ti->ti_dport, ti->ti_sport, u_short);
#undef xchg