LXR linux/drivers/scsi/libfc/fc

   1/*
   2 * Copyright(c) 2007 Intel Corporation. All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or modify it
   5 * under the terms and conditions of the GNU General Public License,
   6 * version 2, as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope it will be useful, but WITHOUT
   9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11 * more details.
  12 *
  13 * You should have received a copy of the GNU General Public License along with
  14 * this program; if not, write to the Free Software Foundation, Inc.,
  15 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  16 *
  17 * Maintained at www.Open-FCoE.org
  18 */
  19
  20/*
  21 * Frame allocation.
  22 */
  23#include <linux/module.h>
  24#include <linux/kernel.h>
  25#include <linux/skbuff.h>
  26#include <linux/crc32.h>
  27#include <linux/gfp.h>
  28
  29#include <scsi/fc_frame.h>
  30
  31/*
  32 * Check the CRC in a frame.
  33 */
  34u32 fc_frame_crc_check(struct fc_frame *fp)
  35{
  36        u32 crc;
  37        u32 error;
  38        const u8 *bp;
  39        unsigned int len;
  40
  41        WARN_ON(!fc_frame_is_linear(fp));
  42        fr_flags(fp) &= ~FCPHF_CRC_UNCHECKED;
  43        len = (fr_len(fp) + 3) & ~3;    /* round up length to include fill */
  44        bp = (const u8 *) fr_hdr(fp);
  45        crc = ~crc32(~0, bp, len);
  46        error = crc ^ fr_crc(fp);
  47        return error;
  48}
  49EXPORT_SYMBOL(fc_frame_crc_check);
  50
  51/*
  52 * Allocate a frame intended to be sent.
  53 * Get an sk_buff for the frame and set the length.
  54 */
  55struct fc_frame *_fc_frame_alloc(size_t len)
  56{
  57        struct fc_frame *fp;
  58        struct sk_buff *skb;
  59
  60        WARN_ON((len % sizeof(u32)) != 0);
  61        len += sizeof(struct fc_frame_header);
  62        skb = alloc_skb_fclone(len + FC_FRAME_HEADROOM + FC_FRAME_TAILROOM +
  63                               NET_SKB_PAD, GFP_ATOMIC);
  64        if (!skb)
  65                return NULL;
  66        skb_reserve(skb, NET_SKB_PAD + FC_FRAME_HEADROOM);
  67        fp = (struct fc_frame *) skb;
  68        fc_frame_init(fp);
  69        skb_put(skb, len);
  70        return fp;
  71}
  72EXPORT_SYMBOL(_fc_frame_alloc);
  73
  74struct fc_frame *fc_frame_alloc_fill(struct fc_lport *lp, size_t payload_len)
  75{
  76        struct fc_frame *fp;
  77        size_t fill;
  78
  79        fill = payload_len % 4;
  80        if (fill != 0)
  81                fill = 4 - fill;
  82        fp = _fc_frame_alloc(payload_len + fill);
  83        if (fp) {
  84                memset((char *) fr_hdr(fp) + payload_len, 0, fill);
  85                /* trim is OK, we just allocated it so there are no fragments */
  86                skb_trim(fp_skb(fp),
  87                         payload_len + sizeof(struct fc_frame_header));
  88        }
  89        return fp;
  90}
  91EXPORT_SYMBOL(fc_frame_alloc_fill);
  92