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