nsec3_get_salt
if(!nsec3_get_salt(rrset, r, salt, saltlen))
(void)nsec3_get_salt(h1->nsec3, h1->rr, &s1, &s1len);
(void)nsec3_get_salt(h2->nsec3, h2->rr, &s2, &s2len);
if(!nsec3_get_salt(c->nsec3, c->rr, &salt, &saltlen))
if(!nsec3_get_salt(rrset, r, salt, saltlen))
(void)nsec3_get_salt(h1->nsec3, h1->rr, &s1, &s1len);
(void)nsec3_get_salt(h2->nsec3, h2->rr, &s2, &s2len);
if(!nsec3_get_salt(c->nsec3, c->rr, &salt, &saltlen))