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