13 #include <unordered_map>
26 #define EPOLL_MAX_EVENTS 8192
27 #define EPOLL_TIMEOUT_MS 20
28 #define MAX_CLIENT_REQUEST 16384
29 #define REQUEST_READ_TIMEOUT_SEC 60
31 class CubemapStateProto;
35 // See Server::hls_zombies, below.
37 std::string remote_addr;
40 std::string user_agent;
44 class Server : public Thread {
49 // Get the list of all currently connected clients.
50 std::vector<ClientStats> get_client_stats() const;
52 // See hls_zombies, below.
53 std::vector<HLSZombie> get_hls_zombies();
55 // Set header (both HTTP header and any stream headers) for the given stream.
56 void set_header(int stream_index,
57 const std::string &http_header,
58 const std::string &stream_header);
60 // Set that the given stream should use the given max pacing rate from now on.
61 // NOTE: This should be set before any clients are connected!
62 void set_pacing_rate(int stream_index, uint32_t pacing_rate);
64 // These will be deferred until the next time an iteration in do_work() happens,
65 // and the order between them are undefined.
66 // XXX: header should ideally be ordered with respect to data.
67 void add_client_deferred(int sock, Acceptor *acceptor);
68 void add_data_deferred(int stream_index, const char *data, size_t bytes, uint16_t metacube_flags, const RationalPTS &pts);
70 // These should not be called while running, since that would violate
71 // threading assumptions (ie., that epoll is only called from one thread
73 CubemapStateProto serialize(std::unordered_map<const std::string *, size_t> *short_response_pool);
74 void add_client_from_serialized(const ClientProto &client, const std::vector<std::shared_ptr<const std::string>> &short_responses);
75 int add_stream(const std::string &url,
76 const std::string &hls_url,
77 size_t bytes_received,
78 size_t prebuffering_bytes,
79 Stream::Encoding encoding,
80 Stream::Encoding src_encoding,
81 unsigned hls_frag_duration,
82 size_t hls_backlog_margin,
83 const std::string &allow_origin);
84 int add_stream_from_serialized(const StreamProto &stream, int data_fd);
85 void add_hls_zombie_from_serialized(const HLSZombieProto &hls_zombie);
86 int lookup_stream_by_url(const std::string &url) const;
87 void set_backlog_size(int stream_index, size_t new_size);
88 void set_prebuffering_bytes(int stream_index, size_t new_amount);
89 void set_encoding(int stream_index, Stream::Encoding encoding);
90 void set_src_encoding(int stream_index, Stream::Encoding encoding);
91 void set_hls_frag_duration(int stream_index, unsigned hls_frag_duration);
92 void set_hls_backlog_margin(int stream_index, size_t hls_backlog_margin);
93 void set_allow_origin(int stream_index, const std::string &allow_origin);
94 void register_hls_url(int stream_index, const std::string &hls_url);
95 void add_gen204(const std::string &url, const std::string &allow_origin);
96 void create_tls_context_for_acceptor(const Acceptor *acceptor);
99 // Mutex protecting queued_add_clients.
100 // Note that if you want to hold both this and <mu> below,
101 // you will need to take <mu> before this one.
102 mutable std::mutex queued_clients_mutex;
104 // Deferred commands that should be run from the do_work() thread as soon as possible.
105 // We defer these for two reasons:
107 // - We only want to fiddle with epoll from one thread at any given time,
108 // and doing add_client() from the acceptor thread would violate that.
109 // - We don't want the input thread(s) hanging on <mu> when doing
110 // add_data(), since they want to do add_data() rather often, and <mu>
111 // can be taken a lot of the time.
113 // Protected by <queued_clients_mutex>.
114 std::vector<std::pair<int, Acceptor *>> queued_add_clients;
116 // All variables below this line are protected by the mutex.
117 mutable std::mutex mu;
120 std::vector<std::unique_ptr<Stream>> streams;
122 // Map from URL to index into <streams>.
123 std::unordered_map<std::string, int> stream_url_map, stream_hls_url_map;
125 // Map from URL to CORS Allow-Origin header (or empty string).
126 std::unordered_map<std::string, std::string> ping_url_map;
128 // Map from file descriptor to client.
129 std::unordered_map<int, Client> clients;
131 // A list of all clients, ordered by the time they connected (first element),
132 // and their file descriptor (second element). It is ordered by connection time
133 // (and thus also by read timeout time) so that we can read clients from the
134 // start and stop processing once we get to one that isn't ready to be
135 // timed out yet (which means we only have to look at each client exactly once,
136 // save for the first element of the queue, which is always checked).
138 // Note that when we delete a client, we don't update this queue.
139 // This means that when reading it, we need to check if the client it
140 // describes is still exists (ie., that the fd still exists, and that
141 // the timespec matches).
142 std::queue<std::pair<timespec, int>> clients_ordered_by_connect_time;
144 // HLS is harder to keep viewer statistics for than regular streams,
145 // since there's no 1:1 mapping between ongoing HTTP connections and
146 // actual viewers. After a HLS fragment has been successfully sent,
147 // we keep a note of that in this structure, so that we can add some
148 // fake entries in the .stats file for clients that we believe are still
149 // watching, but are not downloading anything right now. We clean this
150 // out whenever we write statistics centrally.
152 // The structure is keyed by X-Playback-Session-Id if it exists
153 // (typically iOS clients) or IP address otherwise; we can't use the socket,
154 // since clients can (and do) keep open multiple HTTP connections for
155 // the same video playack session, and may also close the socket
156 // between downloading fragments. This means multiple clients between
157 // the same NAT may be undercounted, but that's how it is.
158 std::unordered_map<std::string, HLSZombie> hls_zombies;
160 // Used for epoll implementation (obviously).
162 epoll_event events[EPOLL_MAX_EVENTS];
164 // For each TLS-enabled acceptor, our private server context for its key pair.
165 std::unordered_map<const Acceptor *, TLSContext *> tls_server_contexts;
167 // The actual worker thread.
168 virtual void do_work();
170 // Process a client; read and write data as far as we can.
171 // After this call, one of these four is true:
173 // 1. The socket is closed, and the client deleted.
174 // 2. We are still waiting for more data from the client.
175 // 3. We've sent all the data we have to the client,
176 // and put it in <sleeping_clients>.
177 // 4. The socket buffer is full (which means we still have
178 // data outstanding).
180 // For #2, we listen for EPOLLIN events. For #3 and #4, we listen
181 // for EPOLLOUT in edge-triggered mode; it will never fire for #3,
182 // but it's cheaper than taking it in and out all the time.
183 void process_client(Client *client);
185 // If the TLS library wants to write anything to this client,
186 // output it. Returns true if the processing should go to sleep
187 // (an error, or lack of outgoing buffer space).
188 bool send_pending_tls_data(Client *client);
190 // Reads regular data fro ma socket. Returns -1 if the processing
191 // should go to sleep (an error, or no data available yet), otherwise
192 // the number of bytes read.
193 int read_plain_data(Client *client, char *buf, size_t max_size);
195 // Reads (decrypted) data from a TLS socket. Returns -1 if the processing
196 // should go to sleep (an error, or no data available yet), otherwise
197 // the number of bytes read. The buffer will be used as scratch space
198 // for TLS data, so it can be overwritten by more bytes than what is returned.
199 int read_tls_data(Client *client, char *buf, size_t max_size);
201 // Close a given client socket, and clean up after it.
202 void close_client(Client *client);
204 // Listen for a different set of epoll events.
205 void change_epoll_events(Client *client, uint32_t events);
207 // If we're supposed to listen for more requests (persistent HTTP connections),
208 // puts the client back into READING_REQUEST, changes its epoll flags and returns
210 bool more_requests(Client *client);
212 // Parse the HTTP request. Returns a HTTP status code (200/204/400/404).
213 int parse_request(Client *client);
215 // Construct the HTTP header for a regular stream, and set the client into
216 // the SENDING_HEADER state.
217 void construct_stream_header(Client *client);
219 // Construct a HLS playlist (or get it from the cache), and set the client into
220 // the SENDING_HEADER state.
221 void construct_hls_playlist(Client *client);
223 // Construct a generic error with the given line, and set the client into
224 // the SENDING_SHORT_RESPONSE state.
225 void construct_error(Client *client, int error_code);
227 // Construct a 204, and set the client into the SENDING_SHORT_RESPONSE state.
228 void construct_204(Client *client);
230 void process_queued_data();
231 void skip_lost_data(Client *client);
233 void add_client(int sock, Acceptor *acceptor);
235 // Mark that a client just went into READING_REQUEST state, so we should
236 // note the current time of day and then put it into <clients_ordered_by_connect_time>.
237 void start_client_timeout_timer(Client *client);
240 #endif // !defined(_SERVER_H)