Commit 740e5dc5 authored by Daniel Verkamp's avatar Daniel Verkamp
Browse files

iscsi: refactor and simplify digest calculations 



Factor out the common PDU header and data digest calculations into
helper functions in iscsi.c.  This eliminates the need for the crc32c.c
iSCSI-specific padding functions spdk_fixup_crc32c() and spdk_crc32c(),
so remove them.

Change-Id: I8cbf269c43177d7483f1df2e7ce9ce83776e7169
Signed-off-by: default avatarDaniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/369312


Tested-by: default avatarSPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
parent 30c42b9b

lib/iscsi/crc32c.c

+0 −35
Original line number Diff line number Diff line
@@ -93,38 +93,3 @@ spdk_update_crc32c(const uint8_t *buf, size_t len, uint32_t crc) 
	return crc;

}

#endif /* USE_ISAL */
 


uint32_t

spdk_fixup_crc32c(size_t total, uint32_t crc)

{

	uint8_t padding[ISCSI_ALIGNMENT];

	size_t pad_length;

	size_t rest;



	if (total == 0)

		return crc;

	rest = total % ISCSI_ALIGNMENT;

	if (rest != 0) {

		pad_length = ISCSI_ALIGNMENT;

		pad_length -= rest;

		if (pad_length > 0 && pad_length < sizeof padding) {

			memset(padding, 0, sizeof padding);

			crc = spdk_update_crc32c(padding, pad_length, crc);

		}

	}

	return crc;

}



uint32_t

spdk_crc32c(const uint8_t *buf, size_t len)

{

	uint32_t crc32c;



	crc32c = SPDK_CRC32C_INITIAL;

	crc32c = spdk_update_crc32c(buf, len, crc32c);

	if ((len % ISCSI_ALIGNMENT) != 0) {

		crc32c = spdk_fixup_crc32c(len, crc32c);

	}

	crc32c = crc32c ^ SPDK_CRC32C_XOR;

	return crc32c;

}

lib/iscsi/crc32c.h

+0 −2
Original line number Diff line number Diff line
@@ -48,7 +48,5 @@ uint32_t crc32_iscsi(const uint8_t *buf, size_t len, uint32_t crc); 
#else

uint32_t spdk_update_crc32c(const uint8_t *buf, size_t len, uint32_t crc);

#endif

uint32_t spdk_fixup_crc32c(size_t total, uint32_t crc);

uint32_t spdk_crc32c(const uint8_t *buf, size_t len);



#endif /* SPDK_CRC32C_H */

lib/iscsi/iscsi.c

+46 −34
Original line number Diff line number Diff line
@@ -303,6 +303,48 @@ spdk_islun2lun(uint64_t islun) 
	return lun_i;

}



static uint32_t

spdk_iscsi_pdu_calc_header_digest(struct spdk_iscsi_pdu *pdu)

{

	uint32_t crc32c;

	uint32_t ahs_len_bytes = pdu->bhs.total_ahs_len * 4;



	crc32c = SPDK_CRC32C_INITIAL;

	crc32c = spdk_update_crc32c((uint8_t *)&pdu->bhs, ISCSI_BHS_LEN, crc32c);



	if (ahs_len_bytes) {

		crc32c = spdk_update_crc32c((uint8_t *)pdu->ahs, ahs_len_bytes, crc32c);

	}



	/* BHS and AHS are always 4-byte multiples in length, so no padding is necessary. */

	crc32c = crc32c ^ SPDK_CRC32C_XOR;

	return crc32c;

}



static uint32_t

spdk_iscsi_pdu_calc_data_digest(struct spdk_iscsi_pdu *pdu)

{

	uint32_t data_len = DGET24(pdu->bhs.data_segment_len);

	uint32_t crc32c;

	uint32_t mod;



	crc32c = SPDK_CRC32C_INITIAL;

	crc32c = spdk_update_crc32c(pdu->data, data_len, crc32c);



	mod = data_len % ISCSI_ALIGNMENT;

	if (mod != 0) {

		uint32_t pad_length = ISCSI_ALIGNMENT - mod;

		uint8_t pad[3] = {0, 0, 0};



		assert(pad_length > 0);

		assert(pad_length <= sizeof(pad));

		crc32c = spdk_update_crc32c(pad, pad_length, crc32c);

	}



	crc32c = crc32c ^ SPDK_CRC32C_XOR;

	return crc32c;

}



int

spdk_iscsi_read_pdu(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu **_pdu)

{
@@ -496,21 +538,7 @@ spdk_iscsi_read_pdu(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu **_pdu) 


	/* check digest */

	if (conn->header_digest) {

		if (ahs_len == 0) {

			crc32c = spdk_crc32c((uint8_t *)&pdu->bhs,

					     ISCSI_BHS_LEN);

		} else {

			int upd_total = 0;

			crc32c = SPDK_CRC32C_INITIAL;

			crc32c = spdk_update_crc32c((uint8_t *)&pdu->bhs,

						    ISCSI_BHS_LEN, crc32c);

			upd_total += ISCSI_BHS_LEN;

			crc32c = spdk_update_crc32c((uint8_t *)pdu->ahs,

						    ahs_len, crc32c);

			upd_total += ahs_len;

			crc32c = spdk_fixup_crc32c(upd_total, crc32c);

			crc32c = crc32c ^ SPDK_CRC32C_XOR;

		}

		crc32c = spdk_iscsi_pdu_calc_header_digest(pdu);

		rc = MATCH_DIGEST_WORD(pdu->header_digest, crc32c);

		if (rc == 0) {

			SPDK_ERRLOG("header digest error (%s)\n", conn->initiator_name);
@@ -519,7 +547,7 @@ spdk_iscsi_read_pdu(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu **_pdu) 
		}

	}

	if (conn->data_digest && data_len != 0) {

		crc32c = spdk_crc32c(pdu->data, ISCSI_ALIGN(data_len));

		crc32c = spdk_iscsi_pdu_calc_data_digest(pdu);

		rc = MATCH_DIGEST_WORD(pdu->data_digest, crc32c);

		if (rc == 0) {

			SPDK_ERRLOG("data digest error (%s)\n", conn->initiator_name);
@@ -565,23 +593,7 @@ spdk_iscsi_build_iovecs(struct spdk_iscsi_conn *conn, struct iovec *iovec, 


	/* Header Digest */

	if (enable_digest && conn->header_digest) {

		if (total_ahs_len == 0) {

			crc32c = spdk_crc32c((uint8_t *)&pdu->bhs,

					     ISCSI_BHS_LEN);

		} else {

			int upd_total = 0;

			crc32c = SPDK_CRC32C_INITIAL;

			crc32c = spdk_update_crc32c((uint8_t *)&pdu->bhs,

						    ISCSI_BHS_LEN, crc32c);

			upd_total += ISCSI_BHS_LEN;

			crc32c = spdk_update_crc32c((uint8_t *)pdu->ahs,

						    (4 * total_ahs_len),

						    crc32c);

			upd_total += (4 * total_ahs_len);

			crc32c = spdk_fixup_crc32c(upd_total, crc32c);

			crc32c = crc32c ^ SPDK_CRC32C_XOR;

		}



		crc32c = spdk_iscsi_pdu_calc_header_digest(pdu);

		MAKE_DIGEST_WORD(pdu->header_digest, crc32c);



		iovec[iovec_cnt].iov_base = pdu->header_digest;
@@ -598,7 +610,7 @@ spdk_iscsi_build_iovecs(struct spdk_iscsi_conn *conn, struct iovec *iovec, 


	/* Data Digest */

	if (enable_digest && conn->data_digest && data_len != 0) {

		crc32c = spdk_crc32c(pdu->data, ISCSI_ALIGN(data_len));

		crc32c = spdk_iscsi_pdu_calc_data_digest(pdu);

		MAKE_DIGEST_WORD(pdu->data_digest, crc32c);



		iovec[iovec_cnt].iov_base = pdu->data_digest;