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_cmd(fp) (fr_cb(fp)->fr_cmd) 58 #define fr_dir(fp) (fr_cmd(fp)->sc_data_direction) 59 #define fr_crc(fp) (fr_cb(fp)->fr_crc) 60 61 struct fc_frame { 62 struct sk_buff skb; 63 }; 64 65 struct fcoe_rcv_info { 66 struct packet_type *ptype; 67 struct fc_lport *fr_dev; /* transport layer private pointer */ 68 struct fc_seq *fr_seq; /* for use with exchange manager */ 69 struct scsi_cmnd *fr_cmd; /* for use of scsi command */ 70 u32 fr_crc; 71 u16 fr_max_payload; /* max FC payload */ 72 enum fc_sof fr_sof; /* start of frame delimiter */ 73 enum fc_eof fr_eof; /* end of frame delimiter */ 74 u8 fr_flags; /* flags - see below */ 75 }; 76 77 78 /* 79 * Get fc_frame pointer for an skb that's already been imported. 80 */ 81 static inline struct fcoe_rcv_info *fcoe_dev_from_skb(const struct sk_buff *skb) 82 { 83 BUILD_BUG_ON(sizeof(struct fcoe_rcv_info) > sizeof(skb->cb)); 84 return (struct fcoe_rcv_info *) skb->cb; 85 } 86 87 /* 88 * fr_flags. 89 */ 90 #define FCPHF_CRC_UNCHECKED 0x01 /* CRC not computed, still appended */ 91 92 /* 93 * Initialize a frame. 94 * We don't do a complete memset here for performance reasons. 95 * The caller must set fr_free, fr_hdr, fr_len, fr_sof, and fr_eof eventually. 96 */ 97 static inline void fc_frame_init(struct fc_frame *fp) 98 { 99 fr_dev(fp) = NULL; 100 fr_seq(fp) = NULL; 101 fr_flags(fp) = 0; 102 } 103 104 struct fc_frame *fc_frame_alloc_fill(struct fc_lport *, size_t payload_len); 105 106 struct fc_frame *__fc_frame_alloc(size_t payload_len); 107 108 /* 109 * Get frame for sending via port. 110 */ 111 static inline struct fc_frame *_fc_frame_alloc(struct fc_lport *dev, 112 size_t payload_len) 113 { 114 return __fc_frame_alloc(payload_len); 115 } 116 117 /* 118 * Allocate fc_frame structure and buffer. Set the initial length to 119 * payload_size + sizeof (struct fc_frame_header). 120 */ 121 static inline struct fc_frame *fc_frame_alloc(struct fc_lport *dev, size_t len) 122 { 123 struct fc_frame *fp; 124 125 /* 126 * Note: Since len will often be a constant multiple of 4, 127 * this check will usually be evaluated and eliminated at compile time. 128 */ 129 if ((len % 4) != 0) 130 fp = fc_frame_alloc_fill(dev, len); 131 else 132 fp = _fc_frame_alloc(dev, len); 133 return fp; 134 } 135 136 /* 137 * Free the fc_frame structure and buffer. 138 */ 139 static inline void fc_frame_free(struct fc_frame *fp) 140 { 141 kfree_skb(fp_skb(fp)); 142 } 143 144 static inline int fc_frame_is_linear(struct fc_frame *fp) 145 { 146 return !skb_is_nonlinear(fp_skb(fp)); 147 } 148 149 /* 150 * Get frame header from message in fc_frame structure. 151 * This hides a cast and provides a place to add some checking. 152 */ 153 static inline 154 struct fc_frame_header *fc_frame_header_get(const struct fc_frame *fp) 155 { 156 WARN_ON(fr_len(fp) < sizeof(struct fc_frame_header)); 157 return (struct fc_frame_header *) fr_hdr(fp); 158 } 159 160 /* 161 * Get frame payload from message in fc_frame structure. 162 * This hides a cast and provides a place to add some checking. 163 * The len parameter is the minimum length for the payload portion. 164 * Returns NULL if the frame is too short. 165 * 166 * This assumes the interesting part of the payload is in the first part 167 * of the buffer for received data. This may not be appropriate to use for 168 * buffers being transmitted. 169 */ 170 static inline void *fc_frame_payload_get(const struct fc_frame *fp, 171 size_t len) 172 { 173 void *pp = NULL; 174 175 if (fr_len(fp) >= sizeof(struct fc_frame_header) + len) 176 pp = fc_frame_header_get(fp) + 1; 177 return pp; 178 } 179 180 /* 181 * Get frame payload opcode (first byte) from message in fc_frame structure. 182 * This hides a cast and provides a place to add some checking. Return 0 183 * if the frame has no payload. 184 */ 185 static inline u8 fc_frame_payload_op(const struct fc_frame *fp) 186 { 187 u8 *cp; 188 189 cp = fc_frame_payload_get(fp, sizeof(u8)); 190 if (!cp) 191 return 0; 192 return *cp; 193 194 } 195 196 /* 197 * Get FC class from frame. 198 */ 199 static inline enum fc_class fc_frame_class(const struct fc_frame *fp) 200 { 201 return fc_sof_class(fr_sof(fp)); 202 } 203 204 /* 205 * Check the CRC in a frame. 206 * The CRC immediately follows the last data item *AFTER* the length. 207 * The return value is zero if the CRC matches. 208 */ 209 u32 fc_frame_crc_check(struct fc_frame *); 210 211 static inline u8 fc_frame_rctl(const struct fc_frame *fp) 212 { 213 return fc_frame_header_get(fp)->fh_r_ctl; 214 } 215 216 static inline bool fc_frame_is_cmd(const struct fc_frame *fp) 217 { 218 return fc_frame_rctl(fp) == FC_RCTL_DD_UNSOL_CMD; 219 } 220 221 static inline bool fc_frame_is_read(const struct fc_frame *fp) 222 { 223 if (fc_frame_is_cmd(fp) && fr_cmd(fp)) 224 return fr_dir(fp) == DMA_FROM_DEVICE; 225 return false; 226 } 227 228 static inline bool fc_frame_is_write(const struct fc_frame *fp) 229 { 230 if (fc_frame_is_cmd(fp) && fr_cmd(fp)) 231 return fr_dir(fp) == DMA_TO_DEVICE; 232 return false; 233 } 234 235 /* 236 * Check for leaks. 237 * Print the frame header of any currently allocated frame, assuming there 238 * should be none at this point. 239 */ 240 void fc_frame_leak_check(void); 241 242 #endif /* _FC_FRAME_H_ */ 243