PF_HI
pf_patch_8(pd, &icmp6->icmp6_type, type, PF_HI);
pf_patch_8(pd, &icmp4->icmp_type, type, PF_HI);
pf_patch_8(pd, th_off, th->th_off << 4, PF_HI);
#define PF_LO (!PF_HI)
#define PF_ALGNMNT(off) (((off) % 2) == 0 ? PF_HI : PF_LO)