[SCSI] libfc: A modular Fibre Channel library

libFC is composed of 4 blocks supported by an exchange manager
and a framing library. The upper 4 layers are fc_lport, fc_disc,
fc_rport and fc_fcp. A LLD that uses libfc could choose to
either use libfc's block, or using the transport template
defined in libfc.h, override one or more blocks with its own
implementation.

The EM (Exchange Manager) manages exhcanges/sequences for all
commands- ELS, CT and FCP.

The framing library frames ELS and CT commands.

The fc_lport block manages the library's representation of the
host's FC enabled ports.

The fc_disc block manages discovery of targets as well as
handling changes that occur in the FC fabric (via. RSCN events).

The fc_rport block manages the library's representation of other
entities in the FC fabric. Currently the library uses this block
for targets, its peer when in point-to-point mode and the
directory server, but can be extended for other entities if
needed.

The fc_fcp block interacts with the scsi-ml and handles all
I/O.

Signed-off-by: Robert Love <robert.w.love@intel.com>
[jejb: added include of delay.h to fix ppc64 compile prob spotted by sfr]
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 89 insertions, 0 deletions

diff --git a/drivers/scsi/libfc/fc_frame.c b/drivers/scsi/libfc/fc_frame.c
new file mode 100644
index 000000000000..63fe00cfe667
--- /dev/null
+++ b/drivers/scsi/libfc/fc_frame.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright(c) 2007 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Maintained at www.Open-FCoE.org
+ */
+
+/*
+ * Frame allocation.
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/crc32.h>
+
+#include <scsi/fc_frame.h>
+
+/*
+ * Check the CRC in a frame.
+ */
+u32 fc_frame_crc_check(struct fc_frame *fp)
+{
+	u32 crc;
+	u32 error;
+	const u8 *bp;
+	unsigned int len;
+
+	WARN_ON(!fc_frame_is_linear(fp));
+	fr_flags(fp) &= ~FCPHF_CRC_UNCHECKED;
+	len = (fr_len(fp) + 3) & ~3;	/* round up length to include fill */
+	bp = (const u8 *) fr_hdr(fp);
+	crc = ~crc32(~0, bp, len);
+	error = crc ^ fr_crc(fp);
+	return error;
+}
+EXPORT_SYMBOL(fc_frame_crc_check);
+
+/*
+ * Allocate a frame intended to be sent via fcoe_xmit.
+ * Get an sk_buff for the frame and set the length.
+ */
+struct fc_frame *__fc_frame_alloc(size_t len)
+{
+	struct fc_frame *fp;
+	struct sk_buff *skb;
+
+	WARN_ON((len % sizeof(u32)) != 0);
+	len += sizeof(struct fc_frame_header);
+	skb = dev_alloc_skb(len + FC_FRAME_HEADROOM + FC_FRAME_TAILROOM);
+	if (!skb)
+		return NULL;
+	fp = (struct fc_frame *) skb;
+	fc_frame_init(fp);
+	skb_reserve(skb, FC_FRAME_HEADROOM);
+	skb_put(skb, len);
+	return fp;
+}
+EXPORT_SYMBOL(__fc_frame_alloc);
+
+
+struct fc_frame *fc_frame_alloc_fill(struct fc_lport *lp, size_t payload_len)
+{
+	struct fc_frame *fp;
+	size_t fill;
+
+	fill = payload_len % 4;
+	if (fill != 0)
+		fill = 4 - fill;
+	fp = __fc_frame_alloc(payload_len + fill);
+	if (fp) {
+		memset((char *) fr_hdr(fp) + payload_len, 0, fill);
+		/* trim is OK, we just allocated it so there are no fragments */
+		skb_trim(fp_skb(fp),
+			 payload_len + sizeof(struct fc_frame_header));
+	}
+	return fp;
+}