pf's on-the-fly checksum adjustments


case AF_INET:
        *pc = pf_cksum_fixup(pf_cksum_fixup(pf_cksum_fixup(*pc,
            ao.addr16[0], an->addr16[0], u),
            ao.addr16[1], an->addr16[1], u),
            po, pn, u);
        break;
case AF_INET6:
        *pc = pf_cksum_fixup(pf_cksum_fixup(pf_cksum_fixup(
            pf_cksum_fixup(pf_cksum_fixup(pf_cksum_fixup(
            pf_cksum_fixup(pf_cksum_fixup(pf_cksum_fixup(*pc,
            ao.addr16[0], an->addr16[0], u),
            ao.addr16[1], an->addr16[1], u),
            ao.addr16[2], an->addr16[2], u),
            ao.addr16[3], an->addr16[3], u),
            ao.addr16[4], an->addr16[4], u),
            ao.addr16[5], an->addr16[5], u),
            ao.addr16[6], an->addr16[6], u),
            ao.addr16[7], an->addr16[7], u),
            po, pn, u);
        break;