sys/sys/syslink.h

   1 /*
   2  * Copyright (c) 2004-2007 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/sys/sys/syslink.h,v 1.5 2007/04/16 17:40:16 dillon Exp $
  35  */
  36
  37 /*
  38  * The syslink infrastructure implements an optimized RPC mechanism across a
  39  * communications link.  RPC functions are grouped together into larger
  40  * protocols.  Prototypes are typically associated with system structures
  41  * but do not have to be.
  42  *
  43  * syslink      - Implements a communications end-point and protocol.  A
  44  *                syslink is typically directly embedded in a related
  45  *                structure.
  46  *
  47  * syslink_proto- Specifies a set of RPC functions.
  48  *
  49  * syslink_desc - Specifies a single RPC function within a protocol.
  50  */
  51
  52 #ifndef _SYS_SYSLINK_H_
  53 #define _SYS_SYSLINK_H_
  54
  55 #ifndef _SYS_TYPES_H_
  56 #include <sys/types.h>
  57 #endif
  58 #ifndef _SYS_TREE_H_
  59 #include <sys/tree.h>
  60 #endif
  61 #ifndef _SYS_SOCKET_H_
  62 #include <sys/socket.h>
  63 #endif
  64
  65 /*
  66  * SYSIDs are 64 bit entities and come in two varieties.  Physical SYSIDs
  67  * are used to efficiently route messages across the mesh, while Logical
  68  * SYSIDs are persistently assigned identifiers representing specific devices
  69  * or specific media or named filesystems.  That is, the logical SYSID
  70  * assigned to a filesystem or ANVIL partition can be stored in that
  71  * filesystem's superblock and allows the filesystem to migrate or
  72  * be multi-homed (have multiple physical SYSIDs representing the same
  73  * logical entity).
  74  *
  75  * Physical SYSIDs can be ever-changing, and any given logical SYSID could
  76  * in fact have multiple physical SYSIDs associated with it.  The mesh is
  77  * self-healing and the combination of the logical and physical sysid
  78  * basically validates the message at the target and determines whether
  79  * the physical SYSID must be recalculated (looked up again) or not.
  80  */
  81 typedef u_int64_t       sysid_t;
  82
  83 /***************************************************************************
  84  *                              PROTOCOL API/ABI                           *
  85  ***************************************************************************
  86  *
  87  * These structures implement the programming interface for end-points and
  88  * RPC calls.
  89  */
  90
  91 struct syslink;
  92 struct syslink_ops;
  93 struct syslink_proto;
  94 struct syslink_transport;
  95 struct syslink_desc;
  96 struct syslink_generic_args;
  97
  98 typedef int (*syslink_func_t)(struct syslink_generic_args *);
  99
 100 /*
 101  * Commands for the syslink system call.
 102  *
 103  * CREATE:      Create a new syslink route node with the route node sysid
 104  *              and label information specified in the passed info structure.
 105  *              0 on success, -1 on failure or if the route node already
 106  *              exists.
 107  *
 108  *              The info structure must also contain the number of bits of
 109  *              address space you wish this route node to use.
 110  *
 111  * DESTROY:     Destroy the existing syslink route node with the route node
 112  *              sysid specified in the passed info structure.
 113  *              0 on success, -1 on failure.
 114  *
 115  * LOCATE:      Locate the first syslink route node with a sysid greater or
 116  *              equal to the sysid specified in the passed info structure.
 117  *              The info structure will be loaded on success and the linkid
 118  *              field will also be cleared.
 119  *
 120  *              To scan route nodes, start by specifying a sysid 0.  On
 121  *              success, increment the sysid in the info structure and loop.
 122  *
 123  *              You can also use the contents of the info structure to
 124  *              initiate a scan of links within the route node via the FIND
 125  *              command.  The sysid will remain unchanged through the scan
 126  *              and on completion you can increment it and loop up to
 127  *              the next LOCATE.
 128  *
 129  * ADD:         Add a link to the route node specified in the info structure.
 130  *              The route node must exist and must contain sufficient
 131  *              address space to handle the new link.  If associating a file
 132  *              descriptor, 0 is returned on success and -1 on failure.
 133  *              If obtaining a direct syslink file descriptor, the new
 134  *              descriptor is returned on success or -1 on failure.
 135  *
 136  *              On return, the linkid in the info structure is filled in and
 137  *              other adjustments may also have been made.
 138  *
 139  *              The info structure must contain the number of bits of
 140  *              address space required by the link.  If 0 is specified,
 141  *              a direct stream or connected socket is expected.  If
 142  *              non-zero, a switch is assumed (typically a switched UDP
 143  *              socket).  An all 0's address is reserved and an all 1's
 144  *              address implies a broadcast.  All other addresses imply
 145  *              single targets within the switched infrastructure.
 146  *
 147  *              FLAGS SUPPORTED:
 148  *
 149  *              SENDTO          This allows you to directly associate a
 150  *                              UDP socket and subnet with a syslink route
 151  *                              node.  To use this option the info structure
 152  *                              must contain a sockaddr representing the
 153  *                              broadcast address.  The low bits are adjusted
 154  *                              based on the size of the subnet (as
 155  *                              specified with PHYSBITS) to forward messages.
 156  *                              If not specified, write() is used and the
 157  *                              target is responsible for any switch
 158  *                              demultiplexing.
 159  *
 160  *              PACKET          Indicates that messages are packetized.
 161  *                              syslink will aggregate multiple syslink
 162  *                              messages into a single packet if possible,
 163  *                              but will not exceed 16384 bytes per packet
 164  *                              and will not attempt to pad messages to
 165  *                              align them for FIFO debuffering.
 166  *
 167  * REM:         Disassociate a link using the route node and linkid
 168  *              specified in the info structure.
 169  *
 170  *              The syslink route node will close() the related descriptor
 171  *              (or cause an EOF to occur for any direct syslink descriptor).
 172  *
 173  * FIND:        Locate the first linkid greater or equal to the linkid
 174  *              in the passed info structure for the route node sysid
 175  *              specified in the info structure, and fill in the rest of the
 176  *              structure as appropriate.
 177  *
 178  *              To locate the first link for any given route sysid, set
 179  *              linkid to 0.  To scan available links, increment the
 180  *              returned linkid before looping.
 181  */
 182
 183 #define SYSLINK_CMD_CREATE      0x00000001      /* create route node */
 184 #define SYSLINK_CMD_DESTROY     0x00000002      /* destroy route node */
 185 #define SYSLINK_CMD_LOCATE      0x00000003      /* locate first route node */
 186 #define SYSLINK_CMD_ADD         0x00000004      /* add link */
 187 #define SYSLINK_CMD_REM         0x00000005      /* remove link */
 188 #define SYSLINK_CMD_FIND        0x00000006      /* locate link info */
 189
 190 #define SYSLINK_LABEL_SIZE      32
 191 #define SYSLINK_ROUTER_MAXBITS  20
 192 /*
 193  * syslink_info structure
 194  *
 195  * This structure contains information about a syslink route node or
 196  * linkage.
 197  */
 198 struct syslink_info {
 199         sysid_t sysid;                  /* route node sysid */
 200         int linkid;                     /* linkid (base physical address) */
 201         int bits;                       /* physical address bits if switched */
 202         int flags;                      /* message control/switch flags */
 203         char label[SYSLINK_LABEL_SIZE]; /* symbolic name */
 204         char reserved[32];
 205         union {
 206                 struct sockaddr sa;     /* required for SLIF_SENDTO */
 207         } u;
 208 };
 209
 210 #define SLIF_PACKET             0x0001  /* packetized, else stream */
 211 #define SLIF_SENDTO             0x0002  /* use sendto() */
 212 #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
 213 #define SLIF_DESTROYED          0x4000
 214 #define SLIF_ERROR              0x8000
 215 #endif
 216
 217 #define SLIF_USERFLAGS          (SLIF_PACKET|SLIF_SENDTO)
 218
 219
 220 /*
 221  * A syslink structure represents an end-point for communications.  System
 222  * structures such as vnodes are typically associated with end-points and
 223  * usually embed a syslink structure.  There is typically one master
 224  * structure (sl_remote_id == 0) and any number of slave structures at
 225  * remote locations (sl_remote_id on slaves point to master).
 226  *
 227  * A ref counter is integrated into the structure and used by SYSLINK to
 228  * keep track of sysid references sent to remote targets.  This counter
 229  * may also be used by the governing structure (e.g. vnode) so long as
 230  * the SYSLINK API is used to manipulate it.
 231  *
 232  * An operations vector implements the ABI for the numerous functions
 233  * associated with the system structure.  E.G. VOPs for vnodes.  The
 234  * ops structure also references the transport and protocol layers.  Using
 235  * vnodes as an example, the ops structure would be replicated from a
 236  * template on a per-mount basis.
 237  */
 238 struct syslink {
 239         sysid_t         sl_source;
 240         sysid_t         sl_target;
 241         int             sl_refs;        /* track references */
 242         struct syslink_ops *sl_ops;     /* operations vector */
 243 };
 244
 245 /*
 246  * The syslink_ops structure is typically embedded as part of a larger system
 247  * structure.  It conatins a reference to the transport layer (if any),
 248  * protocol, and a structural offset range specifying the function vectors
 249  * in the larger system structure.
 250  *
 251  * For example, vnode operations (VOPs) embed this structure in the vop_ops
 252  * structure.
 253  *
 254  * The syslink_ops structure may be replaced as necessary.  The VFS subsystem
 255  * typically replicates syslink_ops on a per-mount basis and stores a pointer
 256  * to the mount point in the larger system structure (vop_ops).
 257  */
 258 struct syslink_ops {
 259         struct syslink_proto *proto;
 260         void *transport;        /* FUTURE USE (transport layer) */
 261         int beg_offset;
 262         int end_offset;
 263 };
 264
 265 /*
 266  * The syslink_desc structure describes a function vector in the protocol.
 267  * This structure may be extended by the protocol to contain additional
 268  * information.
 269  */
 270 struct syslink_desc {
 271         int sd_offset;          /* offset into ops structure */
 272         const char *sd_name;    /* name for debugging */
 273 };
 274
 275 /*
 276  * The syslink_proto structure describes a protocol.  The structure contains
 277  * templates for the various ops structures required to implement the
 278  * protocol.
 279  */
 280 struct syslink_proto {
 281         const char      *sp_name;       /* identifying name */
 282         int             sp_flags;
 283         int             sp_opssize;     /* structure embedding syslink_ops */
 284         struct syslink_ops *sp_call_encode;     /* encode call */
 285         struct syslink_ops *sp_call_decode;     /* decode call */
 286         struct syslink_ops *sp_reply_encode;    /* encode reply */
 287         struct syslink_ops *sp_reply_decode;    /* decode reply */
 288         struct syslink_ops *sp_ops;             /* direct ABI calls */
 289 };
 290
 291 #define SPF_ALLOCATED   0x00000001
 292
 293 /*
 294  * The syslink_generic_args structure contains the base data required in
 295  * the arguments structure passed to any given ops function.  This structure
 296  * is typically extended with the actual call arguments.
 297  */
 298 struct syslink_generic_args {
 299         struct syslink_desc     *a_desc;        /* ABI method description */
 300         struct syslink          *a_syslink;     /* original syslink */
 301         /* extend arguments */
 302 };
 303
 304 typedef struct syslink *syslink_t;
 305 typedef struct syslink_ops *syslink_ops_t;
 306 typedef struct syslink_desc *syslink_desc_t;
 307 typedef struct syslink_proto *syslink_proto_t;
 308 typedef struct syslink_generic_args *syslink_generic_args_t;
 309
 310 #if !defined(_KERNEL)
 311 int syslink(int, int, sysid_t, void *, size_t *);
 312 #endif
 313
 314 #endif