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_fsp(fp)      (fr_cb(fp)->fr_fsp)
  58 #define fr_crc(fp)      (fr_cb(fp)->fr_crc)
  59
  60 struct fc_frame {
  61         struct sk_buff skb;
  62 };
  63
  64 struct fcoe_rcv_info {
  65         struct packet_type  *ptype;
  66         struct fc_lport *fr_dev;        /* transport layer private pointer */
  67         struct fc_seq   *fr_seq;        /* for use with exchange manager */
  68         struct fc_fcp_pkt *fr_fsp;      /* for the corresponding fcp I/O */
  69         u32             fr_crc;
  70         u16             fr_max_payload; /* max FC payload */
  71         enum fc_sof     fr_sof;         /* start of frame delimiter */
  72         enum fc_eof     fr_eof;         /* end of frame delimiter */
  73         u8              fr_flags;       /* flags - see below */
  74 };
  75
  76
  77 /*
  78  * Get fc_frame pointer for an skb that's already been imported.
  79  */
  80 static inline struct fcoe_rcv_info *fcoe_dev_from_skb(const struct sk_buff *skb)
  81 {
  82         BUILD_BUG_ON(sizeof(struct fcoe_rcv_info) > sizeof(skb->cb));
  83         return (struct fcoe_rcv_info *) skb->cb;
  84 }
  85
  86 /*
  87  * fr_flags.
  88  */
  89 #define FCPHF_CRC_UNCHECKED     0x01    /* CRC not computed, still appended */
  90
  91 /*
  92  * Initialize a frame.
  93  * We don't do a complete memset here for performance reasons.
  94  * The caller must set fr_free, fr_hdr, fr_len, fr_sof, and fr_eof eventually.
  95  */
  96 static inline void fc_frame_init(struct fc_frame *fp)
  97 {
  98         fr_dev(fp) = NULL;
  99         fr_seq(fp) = NULL;
 100         fr_flags(fp) = 0;
 101 }
 102
 103 struct fc_frame *fc_frame_alloc_fill(struct fc_lport *, size_t payload_len);
 104
 105 struct fc_frame *__fc_frame_alloc(size_t payload_len);
 106
 107 /*
 108  * Get frame for sending via port.
 109  */
 110 static inline struct fc_frame *_fc_frame_alloc(struct fc_lport *dev,
 111                                                size_t payload_len)
 112 {
 113         return __fc_frame_alloc(payload_len);
 114 }
 115
 116 /*
 117  * Allocate fc_frame structure and buffer.  Set the initial length to
 118  * payload_size + sizeof (struct fc_frame_header).
 119  */
 120 static inline struct fc_frame *fc_frame_alloc(struct fc_lport *dev, size_t len)
 121 {
 122         struct fc_frame *fp;
 123
 124         /*
 125          * Note: Since len will often be a constant multiple of 4,
 126          * this check will usually be evaluated and eliminated at compile time.
 127          */
 128         if ((len % 4) != 0)
 129                 fp = fc_frame_alloc_fill(dev, len);
 130         else
 131                 fp = _fc_frame_alloc(dev, len);
 132         return fp;
 133 }
 134
 135 /*
 136  * Free the fc_frame structure and buffer.
 137  */
 138 static inline void fc_frame_free(struct fc_frame *fp)
 139 {
 140         kfree_skb(fp_skb(fp));
 141 }
 142
 143 static inline int fc_frame_is_linear(struct fc_frame *fp)
 144 {
 145         return !skb_is_nonlinear(fp_skb(fp));
 146 }
 147
 148 /*
 149  * Get frame header from message in fc_frame structure.
 150  * This hides a cast and provides a place to add some checking.
 151  */
 152 static inline
 153 struct fc_frame_header *fc_frame_header_get(const struct fc_frame *fp)
 154 {
 155         WARN_ON(fr_len(fp) < sizeof(struct fc_frame_header));
 156         return (struct fc_frame_header *) fr_hdr(fp);
 157 }
 158
 159 /*
 160  * Get frame payload from message in fc_frame structure.
 161  * This hides a cast and provides a place to add some checking.
 162  * The len parameter is the minimum length for the payload portion.
 163  * Returns NULL if the frame is too short.
 164  *
 165  * This assumes the interesting part of the payload is in the first part
 166  * of the buffer for received data.  This may not be appropriate to use for
 167  * buffers being transmitted.
 168  */
 169 static inline void *fc_frame_payload_get(const struct fc_frame *fp,
 170                                          size_t len)
 171 {
 172         void *pp = NULL;
 173
 174         if (fr_len(fp) >= sizeof(struct fc_frame_header) + len)
 175                 pp = fc_frame_header_get(fp) + 1;
 176         return pp;
 177 }
 178
 179 /*
 180  * Get frame payload opcode (first byte) from message in fc_frame structure.
 181  * This hides a cast and provides a place to add some checking. Return 0
 182  * if the frame has no payload.
 183  */
 184 static inline u8 fc_frame_payload_op(const struct fc_frame *fp)
 185 {
 186         u8 *cp;
 187
 188         cp = fc_frame_payload_get(fp, sizeof(u8));
 189         if (!cp)
 190                 return 0;
 191         return *cp;
 192
 193 }
 194
 195 /*
 196  * Get FC class from frame.
 197  */
 198 static inline enum fc_class fc_frame_class(const struct fc_frame *fp)
 199 {
 200         return fc_sof_class(fr_sof(fp));
 201 }
 202
 203 /*
 204  * Check the CRC in a frame.
 205  * The CRC immediately follows the last data item *AFTER* the length.
 206  * The return value is zero if the CRC matches.
 207  */
 208 u32 fc_frame_crc_check(struct fc_frame *);
 209
 210 static inline u8 fc_frame_rctl(const struct fc_frame *fp)
 211 {
 212         return fc_frame_header_get(fp)->fh_r_ctl;
 213 }
 214
 215 static inline bool fc_frame_is_cmd(const struct fc_frame *fp)
 216 {
 217         return fc_frame_rctl(fp) == FC_RCTL_DD_UNSOL_CMD;
 218 }
 219
 220 /*
 221  * Check for leaks.
 222  * Print the frame header of any currently allocated frame, assuming there
 223  * should be none at this point.
 224  */
 225 void fc_frame_leak_check(void);
 226
 227 #endif /* _FC_FRAME_H_ */