include/vlc_tls.h

   1 /*****************************************************************************
   2  * vlc_tls.h:
   3  *****************************************************************************
   4  * Copyright (C) 2004-2016 Rémi Denis-Courmont
   5  * Copyright (C) 2005-2006 VLC authors and VideoLAN
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU Lesser General Public License as published by
   9  * the Free Software Foundation; either version 2.1 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with this program; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  20  *****************************************************************************/
  21
  22 #ifndef VLC_TLS_H
  23 # define VLC_TLS_H
  24
  25 /**
  26  * \ingroup net
  27  * \defgroup transport Transport layer sockets
  28  * Network stream abstraction
  29  *
  30  * Originally intended for the TLS protocol (Transport Layer Security),
  31  * the Transport Layer Sockets now provides a generic abstraction
  32  * for connection-oriented full-duplex I/O byte streams, such as TCP/IP sockets
  33  * and TLS protocol sessions.
  34  *
  35  * @{
  36  * \file
  37  * Transport layer functions
  38  */
  39
  40 # include <vlc_network.h>
  41
  42 /** Transport layer socket */
  43 typedef struct vlc_tls
  44 {
  45     int (*get_fd)(struct vlc_tls *);
  46     ssize_t (*readv)(struct vlc_tls *, struct iovec *, unsigned);
  47     ssize_t (*writev)(struct vlc_tls *, const struct iovec *, unsigned);
  48     int (*shutdown)(struct vlc_tls *, bool duplex);
  49     void (*close)(struct vlc_tls *);
  50
  51     struct vlc_tls *p;
  52 } vlc_tls_t;
  53
  54 /**
  55  * \defgroup tls Transport Layer Security
  56  * @{
  57  */
  58
  59 /**
  60  * TLS credentials
  61  *
  62  * This structure contains the credentials for establishing TLS sessions.
  63  * This includes root Certificate Authorities (on client side),
  64  * trust and cryptographic parameters,
  65  * public certificates and private keys.
  66  */
  67 typedef struct vlc_tls_creds
  68 {
  69     struct vlc_common_members obj;
  70
  71     module_t *module;
  72     void *sys;
  73
  74     vlc_tls_t *(*open)(struct vlc_tls_creds *, vlc_tls_t *sock,
  75                        const char *host, const char *const *alpn);
  76     int  (*handshake)(struct vlc_tls_creds *, vlc_tls_t *session,
  77                       const char *hostname, const char *service,
  78                       char ** /*restrict*/ alp);
  79 } vlc_tls_creds_t;
  80
  81 /**
  82  * Allocates TLS credentials for a client.
  83  * Credentials can be cached and reused across multiple TLS sessions.
  84  *
  85  * @return TLS credentials object, or NULL on error.
  86  **/
  87 VLC_API vlc_tls_creds_t *vlc_tls_ClientCreate(vlc_object_t *);
  88
  89 /**
  90  * Allocates server TLS credentials.
  91  *
  92  * @param cert path to an x509 certificate (required)
  93  * @param key path to the PKCS private key for the certificate,
  94  *            or NULL to use cert path
  95  *
  96  * @return TLS credentials object, or NULL on error.
  97  */
  98 VLC_API vlc_tls_creds_t *vlc_tls_ServerCreate(vlc_object_t *, const char *cert,
  99                                               const char *key);
 100
 101 static inline int vlc_tls_SessionHandshake (vlc_tls_creds_t *crd,
 102                                             vlc_tls_t *tls)
 103 {
 104     return crd->handshake(crd, tls, NULL, NULL, NULL);
 105 }
 106
 107 /**
 108  * Releases TLS credentials.
 109  *
 110  * Releases data allocated with vlc_tls_ClientCreate() or
 111  * vlc_tls_ServerCreate().
 112  *
 113  * @param srv object to be destroyed (or NULL)
 114  */
 115 VLC_API void vlc_tls_Delete(vlc_tls_creds_t *);
 116
 117 /**
 118  * Initiates a client TLS session.
 119  *
 120  * Initiates a Transport Layer Security (TLS) session as the client side, using
 121  * trusted root CAs previously loaded with vlc_tls_ClientCreate().
 122  *
 123  * This is a blocking network operation and may be a thread cancellation point.
 124  *
 125  * @param creds X.509 credentials, i.e. set of root certificates of trusted
 126  *              certificate authorities
 127  * @param sock socket through which to establish the secure channel
 128  * @param hostname expected server name, used both as Server Name Indication
 129  *                 and as expected Common Name of the peer certificate [IN]
 130  * @param service unique identifier for the service to connect to
 131  *                (only used locally for certificates database) [IN]
 132  * @param alpn NULL-terminated list of Application Layer Protocols
 133  *             to negotiate, or NULL to not negotiate protocols [IN]
 134  * @param alp storage space for the negotiated Application Layer
 135  *            Protocol or NULL if negotiation was not performed [OUT]
 136  *
 137  * @note The credentials must remain valid until the session is finished.
 138  *
 139  * @return TLS session, or NULL on error.
 140  **/
 141 VLC_API vlc_tls_t *vlc_tls_ClientSessionCreate(vlc_tls_creds_t *creds,
 142                                                vlc_tls_t *sock,
 143                                                const char *host,
 144                                                const char *service,
 145                                                const char *const *alpn,
 146                                                char **alp);
 147
 148 /**
 149  * Creates a TLS server session.
 150  *
 151  * Allocates a Transport Layer Security (TLS) session as the server side, using
 152  * cryptographic keys pair and X.509 certificates chain already loaded with
 153  * vlc_tls_ServerCreate().
 154  *
 155  * Unlike vlc_tls_ClientSessionCreate(), this function does not perform any
 156  * actual network I/O. vlc_tls_SessionHandshake() must be used to perform the
 157  * TLS handshake before sending and receiving data through the TLS session.
 158  *
 159  * This function is non-blocking and is not a cancellation point.
 160  *
 161  * @param creds server credentials, i.e. keys pair and X.509 certificates chain
 162  * @param alpn NULL-terminated list of Application Layer Protocols
 163  *             to negotiate, or NULL to not negotiate protocols
 164  *
 165  * @return TLS session, or NULL on error.
 166  */
 167 VLC_API vlc_tls_t *vlc_tls_ServerSessionCreate(vlc_tls_creds_t *creds,
 168                                                vlc_tls_t *sock,
 169                                                const char *const *alpn);
 170
 171 /** @} */
 172
 173 /**
 174  * Destroys a TLS session down.
 175  *
 176  * All resources associated with the TLS session are released.
 177  *
 178  * If the session was established successfully, then shutdown cleanly, the
 179  * underlying socket can be reused. Otherwise, it must be closed. Either way,
 180  * this function does not close the underlying socket: Use vlc_tls_Close()
 181  * instead to close it at the same.
 182  *
 183  * This function is non-blocking and is not a cancellation point.
 184  */
 185 VLC_API void vlc_tls_SessionDelete (vlc_tls_t *);
 186
 187 static inline int vlc_tls_GetFD(vlc_tls_t *tls)
 188 {
 189     return tls->get_fd(tls);
 190 }
 191
 192 /**
 193  * Receives data through a socket.
 194  *
 195  * This dequeues incoming data from a transport layer socket.
 196  *
 197  * @param buf received buffer start address [OUT]
 198  * @param len buffer length (in bytes)
 199  * @param waitall whether to wait for the exact buffer length (true),
 200  *                or for any amount of data (false)
 201  *
 202  * @note At end of stream, the number of bytes returned may be shorter than
 203  * requested regardless of the "waitall" flag.
 204  *
 205  * @return the number of bytes actually dequeued, or -1 on error.
 206  */
 207 VLC_API ssize_t vlc_tls_Read(vlc_tls_t *, void *buf, size_t len, bool waitall);
 208
 209 /**
 210  * Receives a text line through a socket.
 211  *
 212  * This dequeues one line of text from a transport layer socket.
 213  * @return a heap-allocated nul-terminated string, or NULL on error
 214  */
 215 VLC_API char *vlc_tls_GetLine(vlc_tls_t *);
 216
 217 /**
 218  * Sends data through a socket.
 219  */
 220 VLC_API ssize_t vlc_tls_Write(vlc_tls_t *, const void *buf, size_t len);
 221
 222 /**
 223  * Shuts a connection down.
 224  *
 225  * This sends the connection close notification.
 226  *
 227  * If the TLS protocol is used, this provides a secure indication to the other
 228  * end that no further data will be sent. If using plain TCP/IP, this sets the
 229  * FIN flag.
 230  *
 231  * Data can still be received until a close notification is received from the
 232  * other end.
 233  *
 234  * @param duplex whether to stop receiving data as well
 235  * @retval 0 the session was terminated securely and cleanly
 236  *           (the underlying socket can be reused for other purposes)
 237  * @return -1 the session was terminated locally, but either a notification
 238  *            could not be sent or received (the underlying socket cannot be
 239  *            reused and must be closed)
 240  */
 241 static inline int vlc_tls_Shutdown(vlc_tls_t *tls, bool duplex)
 242 {
 243     return tls->shutdown(tls, duplex);
 244 }
 245
 246 /**
 247  * Closes a connection and its underlying resources.
 248  *
 249  * This function closes the transport layer socket, and terminates any
 250  * underlying connection. For instance, if the TLS protocol is used over a TCP
 251  * stream, this function terminates both the TLS session, and then underlying
 252  * TCP/IP connection.
 253  *
 254  * To close a connection but retain any underlying resources, use
 255  * vlc_tls_SessionDelete() instead.
 256  */
 257 static inline void vlc_tls_Close(vlc_tls_t *session)
 258 {
 259     do
 260     {
 261         vlc_tls_t *p = session->p;
 262
 263         vlc_tls_SessionDelete(session);
 264         session = p;
 265     }
 266     while (session != NULL);
 267 }
 268
 269 /**
 270  * Creates a transport-layer stream from a socket.
 271  *
 272  * Creates a transport-layer I/O stream from a socket file descriptor.
 273  * Data will be sent and received directly through the socket. This can be used
 274  * either to share common code between non-TLS and TLS cases, or for testing
 275  * purposes.
 276  *
 277  * This function is not a cancellation point.
 278  *
 279  * @deprecated This function is transitional. Do not use it directly.
 280  */
 281 VLC_API vlc_tls_t *vlc_tls_SocketOpen(int fd);
 282
 283 /**
 284  * Creates a connected pair of transport-layer sockets.
 285  */
 286 VLC_API int vlc_tls_SocketPair(int family, int protocol, vlc_tls_t *[2]);
 287
 288 struct addrinfo;
 289
 290 /**
 291  * Creates a transport-layer stream from a struct addrinfo.
 292  *
 293  * This function tries to allocate a socket using the specified addrinfo
 294  * structure. Normally, the vlc_tls_SocketOpenTCP() function takes care of
 295  * this. But in some cases, it cannot be used, notably:
 296  * - if the remote destination is not resolved (directly) from getaddrinfo(),
 297  * - if the socket type is not SOCK_STREAM,
 298  * - if the transport protocol is not TCP (IPPROTO_TCP), or
 299  * - if TCP Fast Open should be attempted.
 300  *
 301  * @param ai a filled addrinfo structure (the ai_next member is ignored)
 302  * @param defer_connect whether to attempt a TCP Fast Open connection or not
 303  */
 304 VLC_API vlc_tls_t *vlc_tls_SocketOpenAddrInfo(const struct addrinfo *ai,
 305                                               bool defer_connect);
 306
 307 /**
 308  * Creates a transport-layer TCP stream from a name and port.
 309  *
 310  * This function resolves a hostname, and attempts to establish a TCP/IP
 311  * connection to the specified host and port number.
 312  *
 313  * @note The function currently iterates through the addrinfo linked list.
 314  * Future versions may implement different behaviour (e.g. RFC6555).
 315  *
 316  * @return a transport layer socket on success or NULL on error
 317  */
 318 VLC_API vlc_tls_t *vlc_tls_SocketOpenTCP(vlc_object_t *obj,
 319                                          const char *hostname, unsigned port);
 320
 321 /**
 322  * Initiates a TLS session over TCP.
 323  *
 324  * This function resolves a hostname, attempts to establish a TCP/IP
 325  * connection to the specified host and port number, and finally attempts to
 326  * establish a TLS session over the TCP/IP stream.
 327  *
 328  * See also vlc_tls_SocketOpenTCP() and vlc_tls_SessionCreate().
 329  */
 330 VLC_API vlc_tls_t *vlc_tls_SocketOpenTLS(vlc_tls_creds_t *crd,
 331                                          const char *hostname, unsigned port,
 332                                          const char *service,
 333                                          const char *const *alpn, char **alp);
 334
 335 /** @} */
 336
 337 #endif