include/scsi/fc_frame.h

   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 /*
  32  * The fc_frame interface is used to pass frame data between functions.
  33  * The frame includes the data buffer, length, and SOF / EOF delimiter types.
  34  * A pointer to the port structure of the receiving port is also includeded.
  35  */
  36
  37 #define FC_FRAME_HEADROOM       32      /* headroom for VLAN + FCoE headers */
  38 #define FC_FRAME_TAILROOM       8       /* trailer space for FCoE */
  39
  40 /*
  41  * Information about an individual fibre channel frame received or to be sent.
  42  * The buffer may be in up to 4 additional non-contiguous sections,
  43  * but the linear section must hold the frame header.
  44  */
  45 #define FC_FRAME_SG_LEN         4       /* scatter/gather list maximum length */
  46
  47 #define fp_skb(fp)      (&((fp)->skb))
  48 #define fr_hdr(fp)      ((fp)->skb.data)
  49 #define fr_len(fp)      ((fp)->skb.len)
  50 #define fr_cb(fp)       ((struct fcoe_rcv_info *)&((fp)->skb.cb[0]))
  51 #define fr_dev(fp)      (fr_cb(fp)->fr_dev)
  52 #define fr_seq(fp)      (fr_cb(fp)->fr_seq)
  53 #define fr_sof(fp)      (fr_cb(fp)->fr_sof)
  54 #define fr_eof(fp)      (fr_cb(fp)->fr_eof)
  55 #define fr_flags(fp)    (fr_cb(fp)->fr_flags)
  56 #define fr_max_payload(fp)      (fr_cb(fp)->fr_max_payload)
  57 #define fr_cmd(fp)      (fr_cb(fp)->fr_cmd)
  58 #define fr_dir(fp)      (fr_cmd(fp)->sc_data_direction)
  59 #define fr_crc(fp)      (fr_cb(fp)->fr_crc)
  60
  61 struct fc_frame {
  62         struct sk_buff skb;
  63 };
  64
  65 struct fcoe_rcv_info {
  66         struct packet_type  *ptype;
  67         struct fc_lport *fr_dev;        /* transport layer private pointer */
  68         struct fc_seq   *fr_seq;        /* for use with exchange manager */
  69         struct scsi_cmnd *fr_cmd;       /* for use of scsi command */
  70         u32             fr_crc;
  71         u16             fr_max_payload; /* max FC payload */
  72         enum fc_sof     fr_sof;         /* start of frame delimiter */
  73         enum fc_eof     fr_eof;         /* end of frame delimiter */
  74         u8              fr_flags;       /* flags - see below */
  75 };
  76
  77
  78 /*
  79  * Get fc_frame pointer for an skb that's already been imported.
  80  */
  81 static inline struct fcoe_rcv_info *fcoe_dev_from_skb(const struct sk_buff *skb)
  82 {
  83         BUILD_BUG_ON(sizeof(struct fcoe_rcv_info) > sizeof(skb->cb));
  84         return (struct fcoe_rcv_info *) skb->cb;
  85 }
  86
  87 /*
  88  * fr_flags.
  89  */
  90 #define FCPHF_CRC_UNCHECKED     0x01    /* CRC not computed, still appended */
  91
  92 /*
  93  * Initialize a frame.
  94  * We don't do a complete memset here for performance reasons.
  95  * The caller must set fr_free, fr_hdr, fr_len, fr_sof, and fr_eof eventually.
  96  */
  97 static inline void fc_frame_init(struct fc_frame *fp)
  98 {
  99         fr_dev(fp) = NULL;
 100         fr_seq(fp) = NULL;
 101         fr_flags(fp) = 0;
 102 }
 103
 104 struct fc_frame *fc_frame_alloc_fill(struct fc_lport *, size_t payload_len);
 105
 106 struct fc_frame *__fc_frame_alloc(size_t payload_len);
 107
 108 /*
 109  * Get frame for sending via port.
 110  */
 111 static inline struct fc_frame *_fc_frame_alloc(struct fc_lport *dev,
 112                                                size_t payload_len)
 113 {
 114         return __fc_frame_alloc(payload_len);
 115 }
 116
 117 /*
 118  * Allocate fc_frame structure and buffer.  Set the initial length to
 119  * payload_size + sizeof (struct fc_frame_header).
 120  */
 121 static inline struct fc_frame *fc_frame_alloc(struct fc_lport *dev, size_t len)
 122 {
 123         struct fc_frame *fp;
 124
 125         /*
 126          * Note: Since len will often be a constant multiple of 4,
 127          * this check will usually be evaluated and eliminated at compile time.
 128          */
 129         if ((len % 4) != 0)
 130                 fp = fc_frame_alloc_fill(dev, len);
 131         else
 132                 fp = _fc_frame_alloc(dev, len);
 133         return fp;
 134 }
 135
 136 /*
 137  * Free the fc_frame structure and buffer.
 138  */
 139 static inline void fc_frame_free(struct fc_frame *fp)
 140 {
 141         kfree_skb(fp_skb(fp));
 142 }
 143
 144 static inline int fc_frame_is_linear(struct fc_frame *fp)
 145 {
 146         return !skb_is_nonlinear(fp_skb(fp));
 147 }
 148
 149 /*
 150  * Get frame header from message in fc_frame structure.
 151  * This hides a cast and provides a place to add some checking.
 152  */
 153 static inline
 154 struct fc_frame_header *fc_frame_header_get(const struct fc_frame *fp)
 155 {
 156         WARN_ON(fr_len(fp) < sizeof(struct fc_frame_header));
 157         return (struct fc_frame_header *) fr_hdr(fp);
 158 }
 159
 160 /*
 161  * Get frame payload from message in fc_frame structure.
 162  * This hides a cast and provides a place to add some checking.
 163  * The len parameter is the minimum length for the payload portion.
 164  * Returns NULL if the frame is too short.
 165  *
 166  * This assumes the interesting part of the payload is in the first part
 167  * of the buffer for received data.  This may not be appropriate to use for
 168  * buffers being transmitted.
 169  */
 170 static inline void *fc_frame_payload_get(const struct fc_frame *fp,
 171                                          size_t len)
 172 {
 173         void *pp = NULL;
 174
 175         if (fr_len(fp) >= sizeof(struct fc_frame_header) + len)
 176                 pp = fc_frame_header_get(fp) + 1;
 177         return pp;
 178 }
 179
 180 /*
 181  * Get frame payload opcode (first byte) from message in fc_frame structure.
 182  * This hides a cast and provides a place to add some checking. Return 0
 183  * if the frame has no payload.
 184  */
 185 static inline u8 fc_frame_payload_op(const struct fc_frame *fp)
 186 {
 187         u8 *cp;
 188
 189         cp = fc_frame_payload_get(fp, sizeof(u8));
 190         if (!cp)
 191                 return 0;
 192         return *cp;
 193
 194 }
 195
 196 /*
 197  * Get FC class from frame.
 198  */
 199 static inline enum fc_class fc_frame_class(const struct fc_frame *fp)
 200 {
 201         return fc_sof_class(fr_sof(fp));
 202 }
 203
 204 /*
 205  * Check the CRC in a frame.
 206  * The CRC immediately follows the last data item *AFTER* the length.
 207  * The return value is zero if the CRC matches.
 208  */
 209 u32 fc_frame_crc_check(struct fc_frame *);
 210
 211 static inline u8 fc_frame_rctl(const struct fc_frame *fp)
 212 {
 213         return fc_frame_header_get(fp)->fh_r_ctl;
 214 }
 215
 216 static inline bool fc_frame_is_cmd(const struct fc_frame *fp)
 217 {
 218         return fc_frame_rctl(fp) == FC_RCTL_DD_UNSOL_CMD;
 219 }
 220
 221 static inline bool fc_frame_is_read(const struct fc_frame *fp)
 222 {
 223         if (fc_frame_is_cmd(fp) && fr_cmd(fp))
 224                 return fr_dir(fp) == DMA_FROM_DEVICE;
 225         return false;
 226 }
 227
 228 static inline bool fc_frame_is_write(const struct fc_frame *fp)
 229 {
 230         if (fc_frame_is_cmd(fp) && fr_cmd(fp))
 231                 return fr_dir(fp) == DMA_TO_DEVICE;
 232         return false;
 233 }
 234
 235 /*
 236  * Check for leaks.
 237  * Print the frame header of any currently allocated frame, assuming there
 238  * should be none at this point.
 239  */
 240 void fc_frame_leak_check(void);
 241
 242 #endif /* _FC_FRAME_H_ */