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 /*
  34  * The fc_frame interface is used to pass frame data between functions.
  35  * The frame includes the data buffer, length, and SOF / EOF delimiter types.
  36  * A pointer to the port structure of the receiving port is also includeded.
  37  */
  38
  39 #define FC_FRAME_HEADROOM       32      /* headroom for VLAN + FCoE headers */
  40 #define FC_FRAME_TAILROOM       8       /* trailer space for FCoE */
  41
  42 /* Max number of skb frags allowed, reserving one for fcoe_crc_eof page */
  43 #define FC_FRAME_SG_LEN         (MAX_SKB_FRAGS - 1)
  44
  45 #define fp_skb(fp)      (&((fp)->skb))
  46 #define fr_hdr(fp)      ((fp)->skb.data)
  47 #define fr_len(fp)      ((fp)->skb.len)
  48 #define fr_cb(fp)       ((struct fcoe_rcv_info *)&((fp)->skb.cb[0]))
  49 #define fr_dev(fp)      (fr_cb(fp)->fr_dev)
  50 #define fr_seq(fp)      (fr_cb(fp)->fr_seq)
  51 #define fr_sof(fp)      (fr_cb(fp)->fr_sof)
  52 #define fr_eof(fp)      (fr_cb(fp)->fr_eof)
  53 #define fr_flags(fp)    (fr_cb(fp)->fr_flags)
  54 #define fr_max_payload(fp)      (fr_cb(fp)->fr_max_payload)
  55 #define fr_fsp(fp)      (fr_cb(fp)->fr_fsp)
  56 #define fr_crc(fp)      (fr_cb(fp)->fr_crc)
  57
  58 struct fc_frame {
  59         struct sk_buff skb;
  60 };
  61
  62 struct fcoe_rcv_info {
  63         struct packet_type  *ptype;
  64         struct fc_lport *fr_dev;        /* transport layer private pointer */
  65         struct fc_seq   *fr_seq;        /* for use with exchange manager */
  66         struct fc_fcp_pkt *fr_fsp;      /* for the corresponding fcp I/O */
  67         u32             fr_crc;
  68         u16             fr_max_payload; /* max FC payload */
  69         enum fc_sof     fr_sof;         /* start of frame delimiter */
  70         enum fc_eof     fr_eof;         /* end of frame delimiter */
  71         u8              fr_flags;       /* flags - see below */
  72         u8              granted_mac[ETH_ALEN]; /* FCoE MAC address */
  73 };
  74
  75
  76 /*
  77  * Get fc_frame pointer for an skb that's already been imported.
  78  */
  79 static inline struct fcoe_rcv_info *fcoe_dev_from_skb(const struct sk_buff *skb)
  80 {
  81         BUILD_BUG_ON(sizeof(struct fcoe_rcv_info) > sizeof(skb->cb));
  82         return (struct fcoe_rcv_info *) skb->cb;
  83 }
  84
  85 /*
  86  * fr_flags.
  87  */
  88 #define FCPHF_CRC_UNCHECKED     0x01    /* CRC not computed, still appended */
  89
  90 /*
  91  * Initialize a frame.
  92  * We don't do a complete memset here for performance reasons.
  93  * The caller must set fr_free, fr_hdr, fr_len, fr_sof, and fr_eof eventually.
  94  */
  95 static inline void fc_frame_init(struct fc_frame *fp)
  96 {
  97         fr_dev(fp) = NULL;
  98         fr_seq(fp) = NULL;
  99         fr_flags(fp) = 0;
 100 }
 101
 102 struct fc_frame *fc_frame_alloc_fill(struct fc_lport *, size_t payload_len);
 103 struct fc_frame *_fc_frame_alloc(size_t payload_len);
 104
 105 /*
 106  * Allocate fc_frame structure and buffer.  Set the initial length to
 107  * payload_size + sizeof (struct fc_frame_header).
 108  */
 109 static inline struct fc_frame *fc_frame_alloc(struct fc_lport *dev, size_t len)
 110 {
 111         struct fc_frame *fp;
 112
 113         /*
 114          * Note: Since len will often be a constant multiple of 4,
 115          * this check will usually be evaluated and eliminated at compile time.
 116          */
 117         if (len && len % 4)
 118                 fp = fc_frame_alloc_fill(dev, len);
 119         else
 120                 fp = _fc_frame_alloc(len);
 121         return fp;
 122 }
 123
 124 /*
 125  * Free the fc_frame structure and buffer.
 126  */
 127 static inline void fc_frame_free(struct fc_frame *fp)
 128 {
 129         kfree_skb(fp_skb(fp));
 130 }
 131
 132 static inline int fc_frame_is_linear(struct fc_frame *fp)
 133 {
 134         return !skb_is_nonlinear(fp_skb(fp));
 135 }
 136
 137 /*
 138  * Get frame header from message in fc_frame structure.
 139  * This hides a cast and provides a place to add some checking.
 140  */
 141 static inline
 142 struct fc_frame_header *fc_frame_header_get(const struct fc_frame *fp)
 143 {
 144         WARN_ON(fr_len(fp) < sizeof(struct fc_frame_header));
 145         return (struct fc_frame_header *) fr_hdr(fp);
 146 }
 147
 148 /*
 149  * Get frame payload from message in fc_frame structure.
 150  * This hides a cast and provides a place to add some checking.
 151  * The len parameter is the minimum length for the payload portion.
 152  * Returns NULL if the frame is too short.
 153  *
 154  * This assumes the interesting part of the payload is in the first part
 155  * of the buffer for received data.  This may not be appropriate to use for
 156  * buffers being transmitted.
 157  */
 158 static inline void *fc_frame_payload_get(const struct fc_frame *fp,
 159                                          size_t len)
 160 {
 161         void *pp = NULL;
 162
 163         if (fr_len(fp) >= sizeof(struct fc_frame_header) + len)
 164                 pp = fc_frame_header_get(fp) + 1;
 165         return pp;
 166 }
 167
 168 /*
 169  * Get frame payload opcode (first byte) from message in fc_frame structure.
 170  * This hides a cast and provides a place to add some checking. Return 0
 171  * if the frame has no payload.
 172  */
 173 static inline u8 fc_frame_payload_op(const struct fc_frame *fp)
 174 {
 175         u8 *cp;
 176
 177         cp = fc_frame_payload_get(fp, sizeof(u8));
 178         if (!cp)
 179                 return 0;
 180         return *cp;
 181
 182 }
 183
 184 /*
 185  * Get FC class from frame.
 186  */
 187 static inline enum fc_class fc_frame_class(const struct fc_frame *fp)
 188 {
 189         return fc_sof_class(fr_sof(fp));
 190 }
 191
 192 /*
 193  * Check the CRC in a frame.
 194  * The CRC immediately follows the last data item *AFTER* the length.
 195  * The return value is zero if the CRC matches.
 196  */
 197 u32 fc_frame_crc_check(struct fc_frame *);
 198
 199 static inline u8 fc_frame_rctl(const struct fc_frame *fp)
 200 {
 201         return fc_frame_header_get(fp)->fh_r_ctl;
 202 }
 203
 204 static inline bool fc_frame_is_cmd(const struct fc_frame *fp)
 205 {
 206         return fc_frame_rctl(fp) == FC_RCTL_DD_UNSOL_CMD;
 207 }
 208
 209 /*
 210  * Check for leaks.
 211  * Print the frame header of any currently allocated frame, assuming there
 212  * should be none at this point.
 213  */
 214 void fc_frame_leak_check(void);
 215
 216 #endif /* _FC_FRAME_H_ */