linux/include/scsi/fc_frame.h
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   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#ifndef _FC_FRAME_H_
  21#define _FC_FRAME_H_
  22
  23#include <linux/scatterlist.h>
  24#include <linux/skbuff.h>
  25#include <scsi/scsi_cmnd.h>
  26
  27#include <scsi/fc/fc_fs.h>
  28#include <scsi/fc/fc_fcp.h>
  29#include <scsi/fc/fc_encaps.h>
  30
  31#include <linux/if_ether.h>
  32
  33/* some helpful macros */
  34
  35#define ntohll(x) be64_to_cpu(x)
  36#define htonll(x) cpu_to_be64(x)
  37
  38static inline u32 ntoh24(const u8 *p)
  39{
  40        return (p[0] << 16) | (p[1] << 8) | p[2];
  41}
  42
  43static inline void hton24(u8 *p, u32 v)
  44{
  45        p[0] = (v >> 16) & 0xff;
  46        p[1] = (v >> 8) & 0xff;
  47        p[2] = v & 0xff;
  48}
  49
  50/*
  51 * The fc_frame interface is used to pass frame data between functions.
  52 * The frame includes the data buffer, length, and SOF / EOF delimiter types.
  53 * A pointer to the port structure of the receiving port is also includeded.
  54 */
  55
  56#define FC_FRAME_HEADROOM       32      /* headroom for VLAN + FCoE headers */
  57#define FC_FRAME_TAILROOM       8       /* trailer space for FCoE */
  58
  59/* Max number of skb frags allowed, reserving one for fcoe_crc_eof page */
  60#define FC_FRAME_SG_LEN         (MAX_SKB_FRAGS - 1)
  61
  62#define fp_skb(fp)      (&((fp)->skb))
  63#define fr_hdr(fp)      ((fp)->skb.data)
  64#define fr_len(fp)      ((fp)->skb.len)
  65#define fr_cb(fp)       ((struct fcoe_rcv_info *)&((fp)->skb.cb[0]))
  66#define fr_dev(fp)      (fr_cb(fp)->fr_dev)
  67#define fr_seq(fp)      (fr_cb(fp)->fr_seq)
  68#define fr_sof(fp)      (fr_cb(fp)->fr_sof)
  69#define fr_eof(fp)      (fr_cb(fp)->fr_eof)
  70#define fr_flags(fp)    (fr_cb(fp)->fr_flags)
  71#define fr_encaps(fp)   (fr_cb(fp)->fr_encaps)
  72#define fr_max_payload(fp)      (fr_cb(fp)->fr_max_payload)
  73#define fr_fsp(fp)      (fr_cb(fp)->fr_fsp)
  74#define fr_crc(fp)      (fr_cb(fp)->fr_crc)
  75
  76struct fc_frame {
  77        struct sk_buff skb;
  78};
  79
  80struct fcoe_rcv_info {
  81        struct fc_lport *fr_dev;        /* transport layer private pointer */
  82        struct fc_seq   *fr_seq;        /* for use with exchange manager */
  83        struct fc_fcp_pkt *fr_fsp;      /* for the corresponding fcp I/O */
  84        u32             fr_crc;
  85        u16             fr_max_payload; /* max FC payload */
  86        u8              fr_sof;         /* start of frame delimiter */
  87        u8              fr_eof;         /* end of frame delimiter */
  88        u8              fr_flags;       /* flags - see below */
  89        u8              fr_encaps;      /* LLD encapsulation info (e.g. FIP) */
  90        u8              granted_mac[ETH_ALEN]; /* FCoE MAC address */
  91};
  92
  93
  94/*
  95 * Get fc_frame pointer for an skb that's already been imported.
  96 */
  97static inline struct fcoe_rcv_info *fcoe_dev_from_skb(const struct sk_buff *skb)
  98{
  99        BUILD_BUG_ON(sizeof(struct fcoe_rcv_info) > sizeof(skb->cb));
 100        return (struct fcoe_rcv_info *) skb->cb;
 101}
 102
 103/*
 104 * fr_flags.
 105 */
 106#define FCPHF_CRC_UNCHECKED     0x01    /* CRC not computed, still appended */
 107
 108/*
 109 * Initialize a frame.
 110 * We don't do a complete memset here for performance reasons.
 111 * The caller must set fr_free, fr_hdr, fr_len, fr_sof, and fr_eof eventually.
 112 */
 113static inline void fc_frame_init(struct fc_frame *fp)
 114{
 115        fr_dev(fp) = NULL;
 116        fr_seq(fp) = NULL;
 117        fr_flags(fp) = 0;
 118        fr_encaps(fp) = 0;
 119}
 120
 121struct fc_frame *fc_frame_alloc_fill(struct fc_lport *, size_t payload_len);
 122struct fc_frame *_fc_frame_alloc(size_t payload_len);
 123
 124/*
 125 * Allocate fc_frame structure and buffer.  Set the initial length to
 126 * payload_size + sizeof (struct fc_frame_header).
 127 */
 128static inline struct fc_frame *fc_frame_alloc(struct fc_lport *dev, size_t len)
 129{
 130        struct fc_frame *fp;
 131
 132        /*
 133         * Note: Since len will often be a constant multiple of 4,
 134         * this check will usually be evaluated and eliminated at compile time.
 135         */
 136        if (len && len % 4)
 137                fp = fc_frame_alloc_fill(dev, len);
 138        else
 139                fp = _fc_frame_alloc(len);
 140        return fp;
 141}
 142
 143/*
 144 * Free the fc_frame structure and buffer.
 145 */
 146static inline void fc_frame_free(struct fc_frame *fp)
 147{
 148        kfree_skb(fp_skb(fp));
 149}
 150
 151static inline int fc_frame_is_linear(struct fc_frame *fp)
 152{
 153        return !skb_is_nonlinear(fp_skb(fp));
 154}
 155
 156/*
 157 * Get frame header from message in fc_frame structure.
 158 * This version doesn't do a length check.
 159 */
 160static inline
 161struct fc_frame_header *__fc_frame_header_get(const struct fc_frame *fp)
 162{
 163        return (struct fc_frame_header *)fr_hdr(fp);
 164}
 165
 166/*
 167 * Get frame header from message in fc_frame structure.
 168 * This hides a cast and provides a place to add some checking.
 169 */
 170static inline
 171struct fc_frame_header *fc_frame_header_get(const struct fc_frame *fp)
 172{
 173        WARN_ON(fr_len(fp) < sizeof(struct fc_frame_header));
 174        return __fc_frame_header_get(fp);
 175}
 176
 177/*
 178 * Get source FC_ID (S_ID) from frame header in message.
 179 */
 180static inline u32 fc_frame_sid(const struct fc_frame *fp)
 181{
 182        return ntoh24(__fc_frame_header_get(fp)->fh_s_id);
 183}
 184
 185/*
 186 * Get destination FC_ID (D_ID) from frame header in message.
 187 */
 188static inline u32 fc_frame_did(const struct fc_frame *fp)
 189{
 190        return ntoh24(__fc_frame_header_get(fp)->fh_d_id);
 191}
 192
 193/*
 194 * Get frame payload from message in fc_frame structure.
 195 * This hides a cast and provides a place to add some checking.
 196 * The len parameter is the minimum length for the payload portion.
 197 * Returns NULL if the frame is too short.
 198 *
 199 * This assumes the interesting part of the payload is in the first part
 200 * of the buffer for received data.  This may not be appropriate to use for
 201 * buffers being transmitted.
 202 */
 203static inline void *fc_frame_payload_get(const struct fc_frame *fp,
 204                                         size_t len)
 205{
 206        void *pp = NULL;
 207
 208        if (fr_len(fp) >= sizeof(struct fc_frame_header) + len)
 209                pp = fc_frame_header_get(fp) + 1;
 210        return pp;
 211}
 212
 213/*
 214 * Get frame payload opcode (first byte) from message in fc_frame structure.
 215 * This hides a cast and provides a place to add some checking. Return 0
 216 * if the frame has no payload.
 217 */
 218static inline u8 fc_frame_payload_op(const struct fc_frame *fp)
 219{
 220        u8 *cp;
 221
 222        cp = fc_frame_payload_get(fp, sizeof(u8));
 223        if (!cp)
 224                return 0;
 225        return *cp;
 226
 227}
 228
 229/*
 230 * Get FC class from frame.
 231 */
 232static inline enum fc_class fc_frame_class(const struct fc_frame *fp)
 233{
 234        return fc_sof_class(fr_sof(fp));
 235}
 236
 237/*
 238 * Check the CRC in a frame.
 239 * The CRC immediately follows the last data item *AFTER* the length.
 240 * The return value is zero if the CRC matches.
 241 */
 242u32 fc_frame_crc_check(struct fc_frame *);
 243
 244static inline u8 fc_frame_rctl(const struct fc_frame *fp)
 245{
 246        return fc_frame_header_get(fp)->fh_r_ctl;
 247}
 248
 249static inline bool fc_frame_is_cmd(const struct fc_frame *fp)
 250{
 251        return fc_frame_rctl(fp) == FC_RCTL_DD_UNSOL_CMD;
 252}
 253
 254/*
 255 * Check for leaks.
 256 * Print the frame header of any currently allocated frame, assuming there
 257 * should be none at this point.
 258 */
 259void fc_frame_leak_check(void);
 260
 261#endif /* _FC_FRAME_H_ */
 262
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