nbdsrv.h

   1 #ifndef NBDSRV_H
   2 #define NBDSRV_H
   3
   4 #include "lfs.h"
   5
   6 #include <glib.h>
   7 #include <stdbool.h>
   8 #include <stdint.h>
   9
  10 #include <sys/socket.h>
  11 #include <sys/types.h>
  12 #include <semaphore.h>
  13 #include "nbd.h"
  14
  15 /* Structures */
  16
  17 /**
  18  * Types of virtuatlization
  19  **/
  20 typedef enum {
  21         VIRT_NONE=0,    /**< No virtualization */
  22         VIRT_IPLIT,     /**< Literal IP address as part of the filename */
  23         VIRT_IPHASH,    /**< Replacing all dots in an ip address by a / before
  24                              doing the same as in IPLIT */
  25         VIRT_CIDR,      /**< Every subnet in its own directory */
  26 } VIRT_STYLE;
  27
  28 /**
  29  * Variables associated with a server.
  30  **/
  31 typedef struct {
  32         gchar* exportname;    /**< (unprocessed) filename of the file we're exporting */
  33         uint64_t expected_size; /**< size of the exported file as it was told to
  34                                us through configuration */
  35         gchar* listenaddr;   /**< The IP address we're listening on */
  36         char* authname;      /**< filename of the authorization file */
  37         int flags;           /**< flags associated with this exported file */
  38         VIRT_STYLE virtstyle;/**< The style of virtualization, if any */
  39         uint8_t cidrlen;     /**< The length of the mask when we use
  40                                   CIDR-style virtualization */
  41         gchar* prerun;       /**< command to be ran after connecting a client,
  42                                   but before starting to serve */
  43         gchar* postrun;      /**< command that will be ran after the client
  44                                   disconnects */
  45         gchar* servename;    /**< name of the export as selected by nbd-client */
  46         int max_connections; /**< maximum number of opened connections */
  47         int numclients;      /**< number of clients connected to this export */
  48         gchar* transactionlog;/**< filename for transaction log */
  49         gchar* cowdir;       /**< directory for copy-on-write diff files. */
  50         int refcnt;          /**< reference counter */
  51 } SERVER;
  52
  53 /**
  54   * Variables associated with a client connection
  55   */
  56 typedef struct _client {
  57         uint64_t exportsize;    /**< size of the file we're exporting */
  58         char *clientname;       /**< peer, in human-readable format */
  59         struct sockaddr_storage clientaddr; /**< peer, in binary format, network byte order */
  60         char *exportname;       /**< (processed) filename of the file we're exporting */
  61         GArray *export;         /**< array of FILE_INFO of exported files;
  62                                      array size is always 1 unless we're doing
  63                                      the multiple file option */
  64         pthread_rwlock_t export_lock;
  65         int net;                /**< The actual client socket */
  66         SERVER *server;         /**< The server this client is getting data from */
  67         char* difffilename;     /**< filename of the copy-on-write file, if any */
  68         int difffile;           /**< filedescriptor of copyonwrite file. @todo shouldn't this be an array too? (cfr
  69                                      export) Or make -m and -c mutually exclusive */
  70         uint32_t difffilelen;   /**< number of pages in difffile */
  71         uint32_t *difmap;       /**< see comment on the global difmap for this one */
  72         int transactionlogfd;   /**< fd for transaction log */
  73         char semname[100];      /**< name of the posix sem that protects access to the transaction log */
  74         sem_t *logsem;          /**< posix sem that protects access to the transaction log */
  75         int clientfeats;        /**< Client flags specified during negotiation */
  76         int clientflags;        /**< Internal flags for this client, as determined by nbd-server */
  77         pthread_mutex_t lock;   /**< socket lock */
  78         void *tls_session;      /**< TLS session context. Is NULL unless STARTTLS
  79                                      has been negotiated. */
  80         int (*socket_read)(struct _client*, void* buf, size_t len);
  81         int (*socket_write)(struct _client*, const void* buf, size_t len);
  82         void (*socket_closed)(struct _client*);
  83 } CLIENT;
  84
  85 /**
  86  * Variables associated with an open file
  87  **/
  88 typedef struct {
  89         int fhandle;      /**< file descriptor */
  90         off_t startoff;   /**< starting offset of this file */
  91 } FILE_INFO;
  92
  93 typedef struct {
  94         struct nbd_request *req;
  95         char *buf;
  96         size_t buflen;
  97         size_t current_offset;
  98         uint32_t current_len;
  99         unsigned int is_structured : 1;
 100         unsigned int df : 1;
 101 } READ_CTX;
 102
 103 /* Constants and macros */
 104
 105 /**
 106  * Error domain common for all NBD server errors.
 107  **/
 108 #define NBDS_ERR g_quark_from_static_string("server-error-quark")
 109
 110 /**
 111  * NBD server error codes.
 112  **/
 113 typedef enum {
 114         NBDS_ERR_CFILE_NOTFOUND,          /**< The configuration file is not found */
 115         NBDS_ERR_CFILE_MISSING_GENERIC,   /**< The (required) group "generic" is missing */
 116         NBDS_ERR_CFILE_KEY_MISSING,       /**< A (required) key is missing */
 117         NBDS_ERR_CFILE_VALUE_INVALID,     /**< A value is syntactically invalid */
 118         NBDS_ERR_CFILE_VALUE_UNSUPPORTED, /**< A value is not supported in this build */
 119         NBDS_ERR_CFILE_NO_EXPORTS,        /**< A config file was specified that does not
 120                                                define any exports */
 121         NBDS_ERR_CFILE_INCORRECT_PORT,    /**< The reserved port was specified for an
 122                                                old-style export. */
 123         NBDS_ERR_CFILE_DIR_UNKNOWN,       /**< A directory requested does not exist*/
 124         NBDS_ERR_CFILE_READDIR_ERR,       /**< Error occurred during readdir() */
 125         NBDS_ERR_CFILE_INVALID_SPLICE,    /**< We can't use splice with the other options
 126                                                specified for the export. */
 127         NBDS_ERR_SO_LINGER,               /**< Failed to set SO_LINGER to a socket */
 128         NBDS_ERR_SO_REUSEADDR,            /**< Failed to set SO_REUSEADDR to a socket */
 129         NBDS_ERR_SO_KEEPALIVE,            /**< Failed to set SO_KEEPALIVE to a socket */
 130         NBDS_ERR_GAI,                     /**< Failed to get address info */
 131         NBDS_ERR_SOCKET,                  /**< Failed to create a socket */
 132         NBDS_ERR_BIND,                    /**< Failed to bind an address to socket */
 133         NBDS_ERR_LISTEN,                  /**< Failed to start listening on a socket */
 134         NBDS_ERR_SYS,                     /**< Underlying system call or library error */
 135         NBDS_ERR_CFILE_INVALID_WAIT,      /**< We can't use wait with the other options
 136                                                specified for the export. */
 137 } NBDS_ERRS;
 138
 139 /**
 140   * Logging macros.
 141   *
 142   * @todo remove this. We should use g_log in all cases, and use the
 143   * logging mangler to redirect to syslog if and when necessary.
 144   */
 145 #ifdef ISSERVER
 146 #define msg(prio, ...) syslog(prio, __VA_ARGS__)
 147 #else
 148 #define msg(prio, ...) g_log(G_LOG_DOMAIN, G_LOG_LEVEL_MESSAGE, __VA_ARGS__)
 149 #endif
 150 #define MY_NAME "nbd_server"
 151
 152 /** Per-export flags: */
 153 #define F_READONLY 1      /**< flag to tell us a file is readonly */
 154 #define F_MULTIFILE 2     /**< flag to tell us a file is exported using -m */
 155 #define F_COPYONWRITE 4   /**< flag to tell us a file is exported using
 156                             copyonwrite */
 157 #define F_AUTOREADONLY 8  /**< flag to tell us a file is set to autoreadonly */
 158 #define F_SPARSE 16       /**< flag to tell us copyronwrite should use a sparse file */
 159 #define F_SDP 32          /**< flag to tell us the export should be done using the Socket Direct Protocol for RDMA */
 160 #define F_SYNC 64         /**< Whether to fsync() after a write */
 161 #define F_FLUSH 128       /**< Whether server wants FLUSH to be sent by the client */
 162 #define F_FUA 256         /**< Whether server wants FUA to be sent by the client */
 163 #define F_ROTATIONAL 512  /**< Whether server wants the client to implement the elevator algorithm */
 164 #define F_TEMPORARY 1024  /**< Whether the backing file is temporary and should be created then unlinked */
 165 #define F_TRIM 2048       /**< Whether server wants TRIM (discard) to be sent by the client */
 166 #define F_FIXED 4096      /**< Client supports fixed new-style protocol (and can thus send us extra options */
 167 #define F_TREEFILES 8192  /**< flag to tell us a file is exported using -t */
 168 #define F_FORCEDTLS 16384 /**< TLS is required, either for the server as a whole or for a given export */
 169 #define F_SPLICE 32768    /**< flag to tell us to use splice for read/write operations */
 170 #define F_WAIT 65536      /**< flag to tell us to wait for file creation */
 171 #define F_DATALOG 131072  /**< flag to tell us that the transaction log shall contain the written data */
 172
 173 /** Internal flags (for clientflags) */
 174
 175 #define F_STRUCTURED 1
 176
 177 /* Functions */
 178
 179 /**
 180   * Check whether a given address matches a given netmask.
 181   *
 182   * @param mask the address or netmask to check against, in ASCII representation
 183   * @param addr the address to check
 184   *
 185   * @return true if the address matches the mask, false otherwise; in case of
 186   * failure to parse netmask, returns false with err set appropriately.
 187   * @todo decide what to do with v6-mapped IPv4 addresses.
 188   */
 189 bool address_matches(const char* mask, const struct sockaddr* addr, GError** err);
 190
 191 /**
 192   * Gets a byte to allow for address masking.
 193   *
 194   * @param masklen the length of the requested mask.
 195   * @return if the length of the mask is 8 or longer, 0xFF. Otherwise, a byte
 196   * with `masklen' number of leading bits set to 1, everything else set to 0.
 197   */
 198 uint8_t getmaskbyte(int masklen) G_GNUC_PURE;
 199
 200 /**
 201  * Check whether a client is allowed to connect. Works with an authorization
 202  * file which contains one line per machine or network, with CIDR-style
 203  * netmasks.
 204  *
 205  * @param opts The client who's trying to connect.
 206  * @return 0 - authorization refused, 1 - OK
 207  **/
 208 int authorized_client(CLIENT *opts);
 209
 210 /**
 211  * duplicate server
 212  * @param s the old server we want to duplicate
 213  * @return new duplicated server
 214  **/
 215 SERVER* dup_serve(const SERVER *const s);
 216
 217 /**
 218  * Detect the size of a file.
 219  *
 220  * @param fhandle An open filedescriptor
 221  * @return the size of the file, or UINT64_MAX if detection was
 222  * impossible.
 223  **/
 224 uint64_t size_autodetect(int fhandle);
 225
 226 /**
 227  * increase the ref counter for a SERVER
 228  *
 229  * @param s the server to increase
 230  **/
 231 SERVER* serve_inc_ref(SERVER *s);
 232
 233 /**
 234  * decrement the reference counter or a SERVER
 235  *
 236  * @param s the server to decrement
 237  **/
 238 SERVER* serve_dec_ref(SERVER *s);
 239
 240 /**
 241  * Punch a hole in the backend file (if supported by the current system).
 242  *
 243  * @param req the request for which this is being processed
 244  * @param client the client for which we're processing this request
 245  **/
 246 int exptrim(struct nbd_request* req, CLIENT* client);
 247 #endif //NBDSRV_H