nbd.h (3861B) - Raw
1 /* SPDX-License-Identifier: GPL-1.0+ WITH Linux-syscall-note */ 2 /* 3 * 1999 Copyright (C) Pavel Machek, pavel@ucw.cz. This code is GPL. 4 * 1999/11/04 Copyright (C) 1999 VMware, Inc. (Regis "HPReg" Duchesne) 5 * Made nbd_end_request() use the io_request_lock 6 * 2001 Copyright (C) Steven Whitehouse 7 * New nbd_end_request() for compatibility with new linux block 8 * layer code. 9 * 2003/06/24 Louis D. Langholtz <ldl@aros.net> 10 * Removed unneeded blksize_bits field from nbd_device struct. 11 * Cleanup PARANOIA usage & code. 12 * 2004/02/19 Paul Clements 13 * Removed PARANOIA, plus various cleanup and comments 14 * 2023 Copyright Red Hat 15 * Link to userspace extensions, favor cookie over handle. 16 */ 17 18 #ifndef LINUX_NBD_H 19 #define LINUX_NBD_H 20 21 #include <linux/types.h> 22 23 #define NBD_SET_SOCK _IO( 0xab, 0 ) 24 #define NBD_SET_BLKSIZE _IO( 0xab, 1 ) 25 #define NBD_SET_SIZE _IO( 0xab, 2 ) 26 #define NBD_DO_IT _IO( 0xab, 3 ) 27 #define NBD_CLEAR_SOCK _IO( 0xab, 4 ) 28 #define NBD_CLEAR_QUE _IO( 0xab, 5 ) 29 #define NBD_PRINT_DEBUG _IO( 0xab, 6 ) 30 #define NBD_SET_SIZE_BLOCKS _IO( 0xab, 7 ) 31 #define NBD_DISCONNECT _IO( 0xab, 8 ) 32 #define NBD_SET_TIMEOUT _IO( 0xab, 9 ) 33 #define NBD_SET_FLAGS _IO( 0xab, 10) 34 35 /* 36 * See also https://github.com/NetworkBlockDevice/nbd/blob/master/doc/proto.md 37 * for additional userspace extensions not yet utilized in the kernel module. 38 */ 39 40 enum { 41 NBD_CMD_READ = 0, 42 NBD_CMD_WRITE = 1, 43 NBD_CMD_DISC = 2, 44 NBD_CMD_FLUSH = 3, 45 NBD_CMD_TRIM = 4, 46 /* userspace defines additional extension commands */ 47 NBD_CMD_WRITE_ZEROES = 6, 48 }; 49 50 /* values for flags field, these are server interaction specific. */ 51 #define NBD_FLAG_HAS_FLAGS (1 << 0) /* nbd-server supports flags */ 52 #define NBD_FLAG_READ_ONLY (1 << 1) /* device is read-only */ 53 #define NBD_FLAG_SEND_FLUSH (1 << 2) /* can flush writeback cache */ 54 #define NBD_FLAG_SEND_FUA (1 << 3) /* send FUA (forced unit access) */ 55 #define NBD_FLAG_ROTATIONAL (1 << 4) /* device is rotational */ 56 #define NBD_FLAG_SEND_TRIM (1 << 5) /* send trim/discard */ 57 #define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6) /* supports WRITE_ZEROES */ 58 /* there is a gap here to match userspace */ 59 #define NBD_FLAG_CAN_MULTI_CONN (1 << 8) /* Server supports multiple connections per export. */ 60 61 /* values for cmd flags in the upper 16 bits of request type */ 62 #define NBD_CMD_FLAG_FUA (1 << 16) /* FUA (forced unit access) op */ 63 #define NBD_CMD_FLAG_NO_HOLE (1 << 17) /* Do not punch a hole for WRITE_ZEROES */ 64 65 /* These are client behavior specific flags. */ 66 #define NBD_CFLAG_DESTROY_ON_DISCONNECT (1 << 0) /* delete the nbd device on 67 disconnect. */ 68 #define NBD_CFLAG_DISCONNECT_ON_CLOSE (1 << 1) /* disconnect the nbd device on 69 * close by last opener. 70 */ 71 72 /* userspace doesn't need the nbd_device structure */ 73 74 /* These are sent over the network in the request/reply magic fields */ 75 76 #define NBD_REQUEST_MAGIC 0x25609513 77 #define NBD_REPLY_MAGIC 0x67446698 78 /* Do *not* use magics: 0x12560953 0x96744668. */ 79 /* magic 0x668e33ef for structured reply not supported by kernel yet */ 80 81 /* 82 * This is the packet used for communication between client and 83 * server. All data are in network byte order. 84 */ 85 struct nbd_request { 86 __be32 magic; /* NBD_REQUEST_MAGIC */ 87 __be32 type; /* See NBD_CMD_* */ 88 union { 89 __be64 cookie; /* Opaque identifier for request */ 90 char handle[8]; /* older spelling of cookie */ 91 }; 92 __be64 from; 93 __be32 len; 94 } __attribute__((packed)); 95 96 /* 97 * This is the reply packet that nbd-server sends back to the client after 98 * it has completed an I/O request (or an error occurs). 99 */ 100 struct nbd_reply { 101 __be32 magic; /* NBD_REPLY_MAGIC */ 102 __be32 error; /* 0 = ok, else error */ 103 union { 104 __be64 cookie; /* Opaque identifier from request */ 105 char handle[8]; /* older spelling of cookie */ 106 }; 107 }; 108 #endif /* LINUX_NBD_H */