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 packet_type  *ptype;
  82         struct fc_lport *fr_dev;        /* transport layer private pointer */
  83         struct fc_seq   *fr_seq;        /* for use with exchange manager */
  84         struct fc_fcp_pkt *fr_fsp;      /* for the corresponding fcp I/O */
  85         u32             fr_crc;
  86         u16             fr_max_payload; /* max FC payload */
  87         u8              fr_sof;         /* start of frame delimiter */
  88         u8              fr_eof;         /* end of frame delimiter */
  89         u8              fr_flags;       /* flags - see below */
  90         u8              fr_encaps;      /* LLD encapsulation info (e.g. FIP) */
  91         u8              granted_mac[ETH_ALEN]; /* FCoE MAC address */
  92 };
  93
  94
  95 /*
  96  * Get fc_frame pointer for an skb that's already been imported.
  97  */
  98 static inline struct fcoe_rcv_info *fcoe_dev_from_skb(const struct sk_buff *skb)
  99 {
 100         BUILD_BUG_ON(sizeof(struct fcoe_rcv_info) > sizeof(skb->cb));
 101         return (struct fcoe_rcv_info *) skb->cb;
 102 }
 103
 104 /*
 105  * fr_flags.
 106  */
 107 #define FCPHF_CRC_UNCHECKED     0x01    /* CRC not computed, still appended */
 108
 109 /*
 110  * Initialize a frame.
 111  * We don't do a complete memset here for performance reasons.
 112  * The caller must set fr_free, fr_hdr, fr_len, fr_sof, and fr_eof eventually.
 113  */
 114 static inline void fc_frame_init(struct fc_frame *fp)
 115 {
 116         fr_dev(fp) = NULL;
 117         fr_seq(fp) = NULL;
 118         fr_flags(fp) = 0;
 119         fr_encaps(fp) = 0;
 120 }
 121
 122 struct fc_frame *fc_frame_alloc_fill(struct fc_lport *, size_t payload_len);
 123 struct fc_frame *_fc_frame_alloc(size_t payload_len);
 124
 125 /*
 126  * Allocate fc_frame structure and buffer.  Set the initial length to
 127  * payload_size + sizeof (struct fc_frame_header).
 128  */
 129 static inline struct fc_frame *fc_frame_alloc(struct fc_lport *dev, size_t len)
 130 {
 131         struct fc_frame *fp;
 132
 133         /*
 134          * Note: Since len will often be a constant multiple of 4,
 135          * this check will usually be evaluated and eliminated at compile time.
 136          */
 137         if (len && len % 4)
 138                 fp = fc_frame_alloc_fill(dev, len);
 139         else
 140                 fp = _fc_frame_alloc(len);
 141         return fp;
 142 }
 143
 144 /*
 145  * Free the fc_frame structure and buffer.
 146  */
 147 static inline void fc_frame_free(struct fc_frame *fp)
 148 {
 149         kfree_skb(fp_skb(fp));
 150 }
 151
 152 static inline int fc_frame_is_linear(struct fc_frame *fp)
 153 {
 154         return !skb_is_nonlinear(fp_skb(fp));
 155 }
 156
 157 /*
 158  * Get frame header from message in fc_frame structure.
 159  * This version doesn't do a length check.
 160  */
 161 static inline
 162 struct fc_frame_header *__fc_frame_header_get(const struct fc_frame *fp)
 163 {
 164         return (struct fc_frame_header *)fr_hdr(fp);
 165 }
 166
 167 /*
 168  * Get frame header from message in fc_frame structure.
 169  * This hides a cast and provides a place to add some checking.
 170  */
 171 static inline
 172 struct fc_frame_header *fc_frame_header_get(const struct fc_frame *fp)
 173 {
 174         WARN_ON(fr_len(fp) < sizeof(struct fc_frame_header));
 175         return __fc_frame_header_get(fp);
 176 }
 177
 178 /*
 179  * Get source FC_ID (S_ID) from frame header in message.
 180  */
 181 static inline u32 fc_frame_sid(const struct fc_frame *fp)
 182 {
 183         return ntoh24(__fc_frame_header_get(fp)->fh_s_id);
 184 }
 185
 186 /*
 187  * Get destination FC_ID (D_ID) from frame header in message.
 188  */
 189 static inline u32 fc_frame_did(const struct fc_frame *fp)
 190 {
 191         return ntoh24(__fc_frame_header_get(fp)->fh_d_id);
 192 }
 193
 194 /*
 195  * Get frame payload from message in fc_frame structure.
 196  * This hides a cast and provides a place to add some checking.
 197  * The len parameter is the minimum length for the payload portion.
 198  * Returns NULL if the frame is too short.
 199  *
 200  * This assumes the interesting part of the payload is in the first part
 201  * of the buffer for received data.  This may not be appropriate to use for
 202  * buffers being transmitted.
 203  */
 204 static inline void *fc_frame_payload_get(const struct fc_frame *fp,
 205                                          size_t len)
 206 {
 207         void *pp = NULL;
 208
 209         if (fr_len(fp) >= sizeof(struct fc_frame_header) + len)
 210                 pp = fc_frame_header_get(fp) + 1;
 211         return pp;
 212 }
 213
 214 /*
 215  * Get frame payload opcode (first byte) from message in fc_frame structure.
 216  * This hides a cast and provides a place to add some checking. Return 0
 217  * if the frame has no payload.
 218  */
 219 static inline u8 fc_frame_payload_op(const struct fc_frame *fp)
 220 {
 221         u8 *cp;
 222
 223         cp = fc_frame_payload_get(fp, sizeof(u8));
 224         if (!cp)
 225                 return 0;
 226         return *cp;
 227
 228 }
 229
 230 /*
 231  * Get FC class from frame.
 232  */
 233 static inline enum fc_class fc_frame_class(const struct fc_frame *fp)
 234 {
 235         return fc_sof_class(fr_sof(fp));
 236 }
 237
 238 /*
 239  * Check the CRC in a frame.
 240  * The CRC immediately follows the last data item *AFTER* the length.
 241  * The return value is zero if the CRC matches.
 242  */
 243 u32 fc_frame_crc_check(struct fc_frame *);
 244
 245 static inline u8 fc_frame_rctl(const struct fc_frame *fp)
 246 {
 247         return fc_frame_header_get(fp)->fh_r_ctl;
 248 }
 249
 250 static inline bool fc_frame_is_cmd(const struct fc_frame *fp)
 251 {
 252         return fc_frame_rctl(fp) == FC_RCTL_DD_UNSOL_CMD;
 253 }
 254
 255 /*
 256  * Check for leaks.
 257  * Print the frame header of any currently allocated frame, assuming there
 258  * should be none at this point.
 259  */
 260 void fc_frame_leak_check(void);
 261
 262 #endif /* _FC_FRAME_H_ */