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 #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
  38 static inline u32 ntoh24(const u8 *p)
  39 {
  40         return (p[0] << 16) | (p[1] << 8) | p[2];
  41 }
  42
  43 static 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
  76 struct fc_frame {
  77         struct sk_buff skb;
  78 };
  79
  80 struct 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  */
  97 static 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  */
 113 static 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
 121 struct fc_frame *fc_frame_alloc_fill(struct fc_lport *, size_t payload_len);
 122 struct 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  */
 128 static 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  */
 146 static inline void fc_frame_free(struct fc_frame *fp)
 147 {
 148         kfree_skb(fp_skb(fp));
 149 }
 150
 151 static 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  */
 160 static inline
 161 struct 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  */
 170 static inline
 171 struct 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  */
 180 static 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  */
 188 static 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  */
 203 static 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  */
 218 static 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  */
 232 static 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  */
 242 u32 fc_frame_crc_check(struct fc_frame *);
 243
 244 static inline u8 fc_frame_rctl(const struct fc_frame *fp)
 245 {
 246         return fc_frame_header_get(fp)->fh_r_ctl;
 247 }
 248
 249 static 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  */
 259 void fc_frame_leak_check(void);
 260
 261 #endif /* _FC_FRAME_H_ */