lws-secure-streams.h

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/*
 * libwebsockets - small server side websockets and web server implementation
 *
 * Copyright (C) 2019 - 2021 Andy Green <andy@warmcat.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * included from libwebsockets.h
 *
 *
 * Secure Streams is a *payload-only* client communication channel where all the
 * details about the connection are held in a systemwide policy database and
 * are keyed by the streamtype field... the user of the communication channel
 * does not know or manage the choice of endpoint, tls CA, or even wire
 * protocol.  The advantage is he then does not have any dependency on any of
 * those and they can be changed just by changing the policy database without
 * touching the code using the stream.
 *
 * There are two ways secure streams interfaces to user code:
 *
 * 1) [Linux / RTOS] the natural, smallest interface is to call back to user
 *    code that only operates directly from the lws event loop thread context
 *    (direct callbacks from lws_ss_t)
 *
 *    lws_thread( [user code] ---- lws )
 *
 * 2) [Linux] where the user code is in a different process and communicates
 *    asynchronously via a proxy socket
 *
 *    user_process{ [user code] | shim | socket-}------ lws_process{ lws }
 *
 * In the second, IPC, case, all packets are prepended by one or more bytes
 * indicating the packet type and serializing any associated data, known as
 * Serialized Secure Streams or SSS.
 */
 
 
#define LWS_SS_MTU 1540
 
struct lws_ss_handle;
typedef uint32_t lws_ss_tx_ordinal_t;
 
#if defined(STANDALONE)
#define lws_context lws_context_standalone
struct lws_context_standalone;
#endif
 
/*
 * connection state events
 *
 * If you add states, take care about the state names and state transition
 * validity enforcement tables too
 */
typedef enum {
        /* zero means unset */
        LWSSSCS_CREATING                = 1,
        LWSSSCS_DISCONNECTED,
        LWSSSCS_UNREACHABLE,            /* oridinal arg = 1 = caused by dns
                                         * server reachability failure */
        LWSSSCS_AUTH_FAILED,
        LWSSSCS_CONNECTED,
        LWSSSCS_CONNECTING,
        LWSSSCS_DESTROYING,
        LWSSSCS_POLL,
        LWSSSCS_ALL_RETRIES_FAILED,     /* all retries in bo policy failed */
        LWSSSCS_QOS_ACK_REMOTE,         /* remote peer received and acked tx */
        LWSSSCS_QOS_NACK_REMOTE,
        LWSSSCS_QOS_ACK_LOCAL,          /* local proxy accepted our tx */
        LWSSSCS_QOS_NACK_LOCAL,         /* local proxy refused our tx */
        LWSSSCS_TIMEOUT,                /* optional timeout timer fired */
 
        LWSSSCS_SERVER_TXN,
        LWSSSCS_SERVER_UPGRADE,         /* the server protocol upgraded */
 
        LWSSSCS_EVENT_WAIT_CANCELLED, /* somebody called lws_cancel_service */
 
        LWSSSCS_UPSTREAM_LINK_RETRY,    /* if we are being proxied over some
                                         * intermediate link, this transient
                                         * state may be sent to indicate we are
                                         * waiting to establish that link before
                                         * creation can proceed.. ack is the
                                         * number of ms we have been trying */
 
        LWSSSCS_SINK_JOIN,              /* sinks get this when a new source
                                         * stream joins the sink */
        LWSSSCS_SINK_PART,              /* sinks get this when a new source
                                         * stream leaves the sink */
 
        LWSSSCS_USER_BASE = 1000
} lws_ss_constate_t;
 
enum {
        LWSSS_FLAG_SOM                                          = (1 << 0),
        /* payload contains the start of new message */
        LWSSS_FLAG_EOM                                          = (1 << 1),
        /* payload contains the end of message */
        LWSSS_FLAG_POLL                                         = (1 << 2),
        /* Not a real transmit... poll for rx if protocol needs it */
        LWSSS_FLAG_RELATED_START                                = (1 << 3),
        /* Appears in a zero-length message indicating a message group of zero
         * or more messages is now starting. */
        LWSSS_FLAG_RELATED_END                                  = (1 << 4),
        /* Appears in a zero-length message indicating a message group of zero
         * or more messages has now finished. */
        LWSSS_FLAG_RIDESHARE                                    = (1 << 5),
        /* Serialized payload starts with non-default rideshare name length and
         * name string without NUL, then payload */
        LWSSS_FLAG_PERF_JSON                                    = (1 << 6),
        /* This RX is JSON performance data, only on streams with "perf" flag
         * set */
};
 
/*
 * Returns from state() callback can tell the caller what the user code
 * wants to do
 */
 
typedef enum lws_ss_state_return {
        LWSSSSRET_TX_DONT_SEND          =  1, /* (*tx) only, or failure */
 
        LWSSSSRET_OK                    =  0, /* no error */
        LWSSSSRET_DISCONNECT_ME         = -1, /* caller should disconnect us */
        LWSSSSRET_DESTROY_ME            = -2, /* caller should destroy us */
} lws_ss_state_return_t;
 
enum {
        LWSSSINFLAGS_REGISTER_SINK                      =       (1 << 0),
        LWSSSINFLAGS_PROXIED                            =       (1 << 1),
        LWSSSINFLAGS_SERVER                             =       (1 << 2),
        LWSSSINFLAGS_ACCEPTED                           =       (1 << 3),
        LWSSSINFLAGS_ACCEPTED_SINK                      =       (1 << 4),
};
 
typedef lws_ss_state_return_t (*lws_sscb_rx)(void *userobj, const uint8_t *buf,
                                             size_t len, int flags);
typedef lws_ss_state_return_t (*lws_sscb_tx)(void *userobj,
                                             lws_ss_tx_ordinal_t ord,
                                             uint8_t *buf, size_t *len,
                                             int *flags);
typedef lws_ss_state_return_t (*lws_sscb_state)(void *userobj, void *h_src,
                                                lws_ss_constate_t state,
                                                lws_ss_tx_ordinal_t ack);
 
#if defined(LWS_WITH_SECURE_STREAMS_BUFFER_DUMP)
typedef void (*lws_ss_buffer_dump_cb)(void *userobj, const uint8_t *buf,
                size_t len, int done);
#endif
 
struct lws_ss_policy;
 
typedef struct lws_ss_info {
        const char *streamtype; 
        size_t      user_alloc; 
        size_t      handle_offset; 
        size_t      opaque_user_data_offset;
#if defined(LWS_WITH_SECURE_STREAMS_CPP)
        const struct lws_ss_policy      *policy;
#endif
 
#if defined(LWS_WITH_SYS_FAULT_INJECTION)
        lws_fi_ctx_t                            fic;
#endif
 
        lws_sscb_rx rx;
        lws_sscb_tx tx;
        lws_sscb_state state;
#if defined(LWS_WITH_SECURE_STREAMS_BUFFER_DUMP)
        lws_ss_buffer_dump_cb dump;
#endif
        int         manual_initial_tx_credit;
        uint32_t        client_pid;
        uint8_t         flags;
        uint8_t         sss_protocol_version;
} lws_ss_info_t;
 
#define LWS_SS_USER_TYPEDEF \
        typedef struct { \
                struct lws_ss_handle    *ss; \
                void                    *opaque_data;
 
#define LWS_SS_INFO(_streamtype, _type) \
        const lws_ss_info_t ssi_##_type = { \
                .handle_offset = offsetof(_type, ss), \
                .opaque_user_data_offset = offsetof(_type, opaque_data), \
                .user_alloc = sizeof(_type), \
                .streamtype = _streamtype,
 
#define lws_ss_from_user(_u)            (_u)->ss
#define lws_ss_opaque_from_user(_u)     (_u)->opaque_data
#define lws_ss_cx_from_user(_u)         lws_ss_get_context((_u)->ss)
 
#if defined(LWS_SS_USE_SSPC)
#define lws_context_info_defaults(_x, _y) _lws_context_info_defaults(_x, NULL)
#else
#define lws_context_info_defaults(_x, _y) _lws_context_info_defaults(_x, _y)
#endif
 
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
lws_ss_create(struct lws_context *context, int tsi, const lws_ss_info_t *ssi,
              void *opaque_user_data, struct lws_ss_handle **ppss,
              void *reserved, const char **ppayload_fmt);
 
LWS_VISIBLE LWS_EXTERN void
lws_ss_destroy(struct lws_ss_handle **ppss);
 
LWS_VISIBLE LWS_EXTERN lws_ss_state_return_t LWS_WARN_UNUSED_RESULT
lws_ss_request_tx(struct lws_ss_handle *pss);
 
LWS_VISIBLE LWS_EXTERN lws_ss_state_return_t LWS_WARN_UNUSED_RESULT
lws_ss_request_tx_len(struct lws_ss_handle *pss, unsigned long len);
 
LWS_VISIBLE LWS_EXTERN lws_ss_state_return_t LWS_WARN_UNUSED_RESULT
lws_ss_client_connect(struct lws_ss_handle *h);
 
LWS_VISIBLE LWS_EXTERN int
lws_ss_proxy_create(struct lws_context *context, const char *bind, int port);
 
LWS_VISIBLE LWS_EXTERN const char *
lws_ss_state_name(int state);
 
LWS_VISIBLE LWS_EXTERN struct lws_context *
lws_ss_get_context(struct lws_ss_handle *h);
 
#define LWSSS_TIMEOUT_FROM_POLICY                               0
 
LWS_VISIBLE LWS_EXTERN void
lws_ss_start_timeout(struct lws_ss_handle *h, unsigned int timeout_ms);
 
LWS_VISIBLE LWS_EXTERN void
lws_ss_cancel_timeout(struct lws_ss_handle *h);
 
LWS_VISIBLE LWS_EXTERN void *
lws_ss_to_user_object(struct lws_ss_handle *h);
 
LWS_VISIBLE LWS_EXTERN const char *
lws_ss_rideshare(struct lws_ss_handle *h);
 
 
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
lws_ss_set_metadata(struct lws_ss_handle *h, const char *name,
                    const void *value, size_t len);
 
LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
lws_ss_alloc_set_metadata(struct lws_ss_handle *h, const char *name,
                          const void *value, size_t len);
 
LWS_VISIBLE LWS_EXTERN int
lws_ss_get_metadata(struct lws_ss_handle *h, const char *name,
                    const void **value, size_t *len);
 
LWS_VISIBLE LWS_EXTERN void
lws_ss_server_ack(struct lws_ss_handle *h, int nack);
 
typedef void (*lws_sssfec_cb)(struct lws_ss_handle *h, void *arg);
 
LWS_VISIBLE LWS_EXTERN void
lws_ss_server_foreach_client(struct lws_ss_handle *h, lws_sssfec_cb cb,
                             void *arg);
 
LWS_VISIBLE LWS_EXTERN void
lws_ss_change_handlers(struct lws_ss_handle *h, lws_sscb_rx rx, lws_sscb_tx tx,
                       lws_sscb_state state);
 
LWS_VISIBLE LWS_EXTERN int
lws_ss_add_peer_tx_credit(struct lws_ss_handle *h, int32_t add);
 
LWS_VISIBLE LWS_EXTERN int
lws_ss_get_est_peer_tx_credit(struct lws_ss_handle *h);
 
LWS_VISIBLE LWS_EXTERN const char *
lws_ss_tag(struct lws_ss_handle *h);
 
 
#if defined(LWS_WITH_SECURE_STREAMS_AUTH_SIGV4)
LWS_VISIBLE LWS_EXTERN int
lws_ss_sigv4_set_aws_key(struct lws_context* context, uint8_t idx,
                                const char * keyid, const char * key);
 
LWS_VISIBLE LWS_EXTERN int
lws_aws_filesystem_credentials_helper(const char *path, const char *kid,
                                      const char *ak, char **aws_keyid,
                                      char **aws_key);
 
#endif
 
#if defined(STANDALONE)
#undef lws_context
#endif