static struct xfrm_state * pfkey_msg2xfrm_state(struct net *net,
						const struct sadb_msg *hdr,
						void * const *ext_hdrs)
{
	struct xfrm_state *x;
	const struct sadb_lifetime *lifetime;
	const struct sadb_sa *sa;
	const struct sadb_key *key;
	const struct sadb_x_sec_ctx *sec_ctx;
	uint16_t proto;
	int err;


	sa = ext_hdrs[SADB_EXT_SA - 1];
	if (!sa ||
	    !present_and_same_family(ext_hdrs[SADB_EXT_ADDRESS_SRC-1],
				     ext_hdrs[SADB_EXT_ADDRESS_DST-1]))
		return ERR_PTR(-EINVAL);
	if (hdr->sadb_msg_satype == SADB_SATYPE_ESP &&
	    !ext_hdrs[SADB_EXT_KEY_ENCRYPT-1])
		return ERR_PTR(-EINVAL);
	if (hdr->sadb_msg_satype == SADB_SATYPE_AH &&
	    !ext_hdrs[SADB_EXT_KEY_AUTH-1])
		return ERR_PTR(-EINVAL);
	if (!!ext_hdrs[SADB_EXT_LIFETIME_HARD-1] !=
	    !!ext_hdrs[SADB_EXT_LIFETIME_SOFT-1])
		return ERR_PTR(-EINVAL);

	proto = pfkey_satype2proto(hdr->sadb_msg_satype);
	if (proto == 0)
		return ERR_PTR(-EINVAL);

	/* default error is no buffer space */
	err = -ENOBUFS;

	/* RFC2367:

   Only SADB_SASTATE_MATURE SAs may be submitted in an SADB_ADD message.
   SADB_SASTATE_LARVAL SAs are created by SADB_GETSPI and it is not
   sensible to add a new SA in the DYING or SADB_SASTATE_DEAD state.
   Therefore, the sadb_sa_state field of all submitted SAs MUST be
   SADB_SASTATE_MATURE and the kernel MUST return an error if this is
   not true.

	   However, KAME setkey always uses SADB_SASTATE_LARVAL.
	   Hence, we have to _ignore_ sadb_sa_state, which is also reasonable.
	 */
	if (sa->sadb_sa_auth > SADB_AALG_MAX ||
	    (hdr->sadb_msg_satype == SADB_X_SATYPE_IPCOMP &&
	     sa->sadb_sa_encrypt > SADB_X_CALG_MAX) ||
	    sa->sadb_sa_encrypt > SADB_EALG_MAX)
		return ERR_PTR(-EINVAL);
	key = ext_hdrs[SADB_EXT_KEY_AUTH - 1];
	if (key != NULL &&
	    sa->sadb_sa_auth != SADB_X_AALG_NULL &&
	    ((key->sadb_key_bits+7) / 8 == 0 ||
	     (key->sadb_key_bits+7) / 8 > key->sadb_key_len * sizeof(uint64_t)))
		return ERR_PTR(-EINVAL);
	key = ext_hdrs[SADB_EXT_KEY_ENCRYPT-1];
	if (key != NULL &&
	    sa->sadb_sa_encrypt != SADB_EALG_NULL &&
	    ((key->sadb_key_bits+7) / 8 == 0 ||
	     (key->sadb_key_bits+7) / 8 > key->sadb_key_len * sizeof(uint64_t)))
		return ERR_PTR(-EINVAL);

	x = xfrm_state_alloc(net);
	if (x == NULL)
		return ERR_PTR(-ENOBUFS);

	x->id.proto = proto;
	x->id.spi = sa->sadb_sa_spi;
	x->props.replay_window = min_t(unsigned int, sa->sadb_sa_replay,
					(sizeof(x->replay.bitmap) * 8));
	if (sa->sadb_sa_flags & SADB_SAFLAGS_NOECN)
		x->props.flags |= XFRM_STATE_NOECN;
	if (sa->sadb_sa_flags & SADB_SAFLAGS_DECAP_DSCP)
		x->props.flags |= XFRM_STATE_DECAP_DSCP;
	if (sa->sadb_sa_flags & SADB_SAFLAGS_NOPMTUDISC)
		x->props.flags |= XFRM_STATE_NOPMTUDISC;

	lifetime = ext_hdrs[SADB_EXT_LIFETIME_HARD - 1];
	if (lifetime != NULL) {
		x->lft.hard_packet_limit = _KEY2X(lifetime->sadb_lifetime_allocations);
		x->lft.hard_byte_limit = _KEY2X(lifetime->sadb_lifetime_bytes);
		x->lft.hard_add_expires_seconds = lifetime->sadb_lifetime_addtime;
		x->lft.hard_use_expires_seconds = lifetime->sadb_lifetime_usetime;
	}
	lifetime = ext_hdrs[SADB_EXT_LIFETIME_SOFT - 1];
	if (lifetime != NULL) {
		x->lft.soft_packet_limit = _KEY2X(lifetime->sadb_lifetime_allocations);
		x->lft.soft_byte_limit = _KEY2X(lifetime->sadb_lifetime_bytes);
		x->lft.soft_add_expires_seconds = lifetime->sadb_lifetime_addtime;
		x->lft.soft_use_expires_seconds = lifetime->sadb_lifetime_usetime;
	}

	sec_ctx = ext_hdrs[SADB_X_EXT_SEC_CTX - 1];
	if (sec_ctx != NULL) {
		struct xfrm_user_sec_ctx *uctx = pfkey_sadb2xfrm_user_sec_ctx(sec_ctx);

		if (!uctx)
			goto out;

		err = security_xfrm_state_alloc(x, uctx);
		kfree(uctx);

		if (err)
			goto out;
	}

	key = ext_hdrs[SADB_EXT_KEY_AUTH - 1];
	if (sa->sadb_sa_auth) {
		int keysize = 0;
		struct xfrm_algo_desc *a = xfrm_aalg_get_byid(sa->sadb_sa_auth);
		if (!a || !a->pfkey_supported) {
			err = -ENOSYS;
			goto out;
		}
		if (key)
			keysize = (key->sadb_key_bits + 7) / 8;
		x->aalg = kmalloc(sizeof(*x->aalg) + keysize, GFP_KERNEL);
		if (!x->aalg)
			goto out;
		strcpy(x->aalg->alg_name, a->name);
		x->aalg->alg_key_len = 0;
		if (key) {
			x->aalg->alg_key_len = key->sadb_key_bits;
			memcpy(x->aalg->alg_key, key+1, keysize);
		}
		x->aalg->alg_trunc_len = a->uinfo.auth.icv_truncbits;
		x->props.aalgo = sa->sadb_sa_auth;
		/* x->algo.flags = sa->sadb_sa_flags; */
	}
	if (sa->sadb_sa_encrypt) {
		if (hdr->sadb_msg_satype == SADB_X_SATYPE_IPCOMP) {
			struct xfrm_algo_desc *a = xfrm_calg_get_byid(sa->sadb_sa_encrypt);
			if (!a || !a->pfkey_supported) {
				err = -ENOSYS;
				goto out;
			}
			x->calg = kmalloc(sizeof(*x->calg), GFP_KERNEL);
			if (!x->calg)
				goto out;
			strcpy(x->calg->alg_name, a->name);
			x->props.calgo = sa->sadb_sa_encrypt;
		} else {
			int keysize = 0;
			struct xfrm_algo_desc *a = xfrm_ealg_get_byid(sa->sadb_sa_encrypt);
			if (!a || !a->pfkey_supported) {
				err = -ENOSYS;
				goto out;
			}
			key = (struct sadb_key*) ext_hdrs[SADB_EXT_KEY_ENCRYPT-1];
			if (key)
				keysize = (key->sadb_key_bits + 7) / 8;
			x->ealg = kmalloc(sizeof(*x->ealg) + keysize, GFP_KERNEL);
			if (!x->ealg)
				goto out;
			strcpy(x->ealg->alg_name, a->name);
			x->ealg->alg_key_len = 0;
			if (key) {
				x->ealg->alg_key_len = key->sadb_key_bits;
				memcpy(x->ealg->alg_key, key+1, keysize);
			}
			x->props.ealgo = sa->sadb_sa_encrypt;
		}
	}
	/* x->algo.flags = sa->sadb_sa_flags; */

	x->props.family = pfkey_sadb_addr2xfrm_addr((struct sadb_address *) ext_hdrs[SADB_EXT_ADDRESS_SRC-1],
						    &x->props.saddr);
	pfkey_sadb_addr2xfrm_addr((struct sadb_address *) ext_hdrs[SADB_EXT_ADDRESS_DST-1],
				  &x->id.daddr);

	if (ext_hdrs[SADB_X_EXT_SA2-1]) {
		const struct sadb_x_sa2 *sa2 = ext_hdrs[SADB_X_EXT_SA2-1];
		int mode = pfkey_mode_to_xfrm(sa2->sadb_x_sa2_mode);
		if (mode < 0) {
			err = -EINVAL;
			goto out;
		}
		x->props.mode = mode;
		x->props.reqid = sa2->sadb_x_sa2_reqid;
	}

	if (ext_hdrs[SADB_EXT_ADDRESS_PROXY-1]) {
		const struct sadb_address *addr = ext_hdrs[SADB_EXT_ADDRESS_PROXY-1];

		/* Nobody uses this, but we try. */
		x->sel.family = pfkey_sadb_addr2xfrm_addr(addr, &x->sel.saddr);
		x->sel.prefixlen_s = addr->sadb_address_prefixlen;
	}

	if (!x->sel.family)
		x->sel.family = x->props.family;

	if (ext_hdrs[SADB_X_EXT_NAT_T_TYPE-1]) {
		const struct sadb_x_nat_t_type* n_type;
		struct xfrm_encap_tmpl *natt;

		x->encap = kmalloc(sizeof(*x->encap), GFP_KERNEL);
		if (!x->encap)
			goto out;

		natt = x->encap;
		n_type = ext_hdrs[SADB_X_EXT_NAT_T_TYPE-1];
		natt->encap_type = n_type->sadb_x_nat_t_type_type;

		if (ext_hdrs[SADB_X_EXT_NAT_T_SPORT-1]) {
			const struct sadb_x_nat_t_port *n_port =
				ext_hdrs[SADB_X_EXT_NAT_T_SPORT-1];
			natt->encap_sport = n_port->sadb_x_nat_t_port_port;
		}
		if (ext_hdrs[SADB_X_EXT_NAT_T_DPORT-1]) {
			const struct sadb_x_nat_t_port *n_port =
				ext_hdrs[SADB_X_EXT_NAT_T_DPORT-1];
			natt->encap_dport = n_port->sadb_x_nat_t_port_port;
		}
		memset(&natt->encap_oa, 0, sizeof(natt->encap_oa));
	}

	err = xfrm_init_state(x);
	if (err)
		goto out;

	x->km.seq = hdr->sadb_msg_seq;
	return x;

out:
	x->km.state = XFRM_STATE_DEAD;
	xfrm_state_put(x);
	return ERR_PTR(err);
}