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