Function esp_input_cb

freebsd/netipsec/xform_esp.c:480–668

* ESP input callback from the crypto driver. */

 * ESP input callback from the crypto driver.
 */
static int
esp_input_cb(struct cryptop *crp)
{
	IPSEC_DEBUG_DECLARE(char buf[128]);
	uint8_t lastthree[3];
	const struct auth_hash *esph;
	struct mbuf *m;
	struct xform_data *xd;
	struct secasvar *sav;
	struct secasindex *saidx;
	crypto_session_t cryptoid;
	int hlen, skip, protoff, error, alen;

	m = crp->crp_buf.cb_mbuf;
	xd = crp->crp_opaque;
	CURVNET_SET(xd->vnet);
	sav = xd->sav;
	skip = xd->skip;
	protoff = xd->protoff;
	cryptoid = xd->cryptoid;
	saidx = &sav->sah->saidx;
	esph = sav->tdb_authalgxform;

	/* Check for crypto errors */
	if (crp->crp_etype) {
		if (crp->crp_etype == EAGAIN) {
			/* Reset the session ID */
			if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
				crypto_freesession(cryptoid);
			xd->cryptoid = crp->crp_session;
			CURVNET_RESTORE();
			return (crypto_dispatch(crp));
		}

		/* EBADMSG indicates authentication failure. */
		if (!(crp->crp_etype == EBADMSG && esph != NULL)) {
			ESPSTAT_INC(esps_noxform);
			DPRINTF(("%s: crypto error %d\n", __func__,
				crp->crp_etype));
			error = crp->crp_etype;
			goto bad;
		}
	}

	/* Shouldn't happen... */
	if (m == NULL) {
		ESPSTAT_INC(esps_crypto);
		DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
		error = EINVAL;
		goto bad;
	}
	ESPSTAT_INC(esps_hist[sav->alg_enc]);

	/* If authentication was performed, check now. */
	if (esph != NULL) {
		alen = xform_ah_authsize(esph);
		AHSTAT_INC(ahs_hist[sav->alg_auth]);
		if (crp->crp_etype == EBADMSG) {