ipsec_decode_transform
ipsec_decode_transform(msg, sa, TAILQ_FIRST(&sa->protos), xf->p);
ipsec_decode_transform(msg, sa, TAILQ_FIRST(&sa->protos),
ipsec_decode_transform(msg, sa, proto, xf->p);
ipsec_decode_transform(msg, sa, proto,
extern void ipsec_decode_transform(struct message *, struct sa *,