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_ */ 217