DSO/dso-transport.h

   1 /* dso-transport.h
   2  *
   3  * Copyright (c) 2018-2019 Apple Computer, Inc. All rights reserved.
   4  *
   5  * Licensed under the Apache License, Version 2.0 (the "License");
   6  * you may not use this file except in compliance with the License.
   7  * You may obtain a copy of the License at
   8  *
   9  *     http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  *
  17  */
  18
  19 #ifndef __DSO_TRANSPORT_H
  20 #define __DSO_TRANSPORT_H
  21
  22 #ifdef DSO_USES_NETWORK_FRAMEWORK
  23 #include <Network/Network.h>
  24 #endif
  25
  26 // Maximum number of IP addresses that we'll deal with as a result of looking up a name
  27 // to which to connect.
  28 #define MAX_DSO_CONNECT_ADDRS 16
  29
  30 // Threshold above which we indicate that a DSO connection isn't writable.   This is advisory,
  31 // but e.g. for a Discovery Relay, if the remote proxy isn't consuming what we are sending, we
  32 // should start dropping packets on the floor rather than just queueing more and more packets.
  33 // 60k may actually be too much.   This is used when we're using NW Framework, because it doesn't
  34 // allow us to use TCP_NOTSENT_LOWAT directly.
  35 #define MAX_UNSENT_BYTES 60000
  36
  37 struct dso_transport {
  38     dso_state_t *dso;                      // DSO state for which this is the transport
  39     struct dso_transport *next;    // Transport is on list of transports.
  40     void *event_context;           // I/O event context
  41     mDNSAddr remote_addr;          // The IP address to which we have connected
  42     int remote_port;               // The port to which we have connected
  43
  44 #ifdef DSO_USES_NETWORK_FRAMEWORK
  45     nw_connection_t connection;
  46     dispatch_data_t to_write;
  47     size_t bytes_to_write;
  48     size_t unsent_bytes;
  49     uint32_t serial;               // Serial number for locating possibly freed dso_transport_t structs
  50     bool write_failed;             // This is set if any of the parts of the dso_write process fail
  51 #else
  52     TCPSocket *connection;         // Socket connected to Discovery Proxy
  53     size_t bytes_needed;
  54     size_t message_length;         // Length of message we are currently accumulating, if known
  55     uint8_t *inbuf;                // Buffer for incoming messages.
  56     size_t inbuf_size;
  57     uint8_t *inbufp;               // Current read pointer (may not be in inbuf)
  58     bool need_length;              // True if we need a 2-byte length
  59
  60     uint8_t lenbuf[2];             // Buffer for storing the length in a DNS TCP message
  61
  62 #define MAX_WRITE_HUNKS 4          // When writing a DSO message, we need this many separate hunks.
  63     const uint8_t *to_write[MAX_WRITE_HUNKS];
  64     ssize_t write_lengths[MAX_WRITE_HUNKS];
  65     int num_to_write;
  66 #endif // DSO_USES_NETWORK_FRAMEWORK
  67
  68     uint8_t *outbuf;               // Output buffer for building and sending DSO messages
  69     size_t outbuf_size;
  70 };
  71
  72 typedef struct dso_lookup dso_lookup_t;
  73 struct dso_lookup {
  74     dso_lookup_t *next;
  75     DNSServiceRef sdref;
  76 };
  77
  78 typedef struct dso_connect_state dso_connect_state_t;
  79 struct dso_connect_state {
  80     dso_connect_state_t *next;
  81     dso_event_callback_t callback;
  82     dso_state_t *dso;
  83     char *detail;
  84     void *context;
  85     TCPListener *listener;
  86
  87     char *hostname;
  88     int num_addrs;
  89     int cur_addr;
  90     mDNSAddr addresses[MAX_DSO_CONNECT_ADDRS];
  91     mDNSIPPort ports[MAX_DSO_CONNECT_ADDRS];
  92     DNSServiceRef lookup;
  93
  94     mDNSBool connecting;
  95     mDNSIPPort config_port, connect_port;
  96 #ifdef DSO_USES_NETWORK_FRAMEWORK
  97     uint32_t serial;
  98     nw_connection_t connection;
  99     bool tls_enabled;
 100 #else
 101     size_t inbuf_size;
 102 #endif
 103     size_t outbuf_size;
 104     int max_outstanding_queries;
 105     mDNSs32 last_event;
 106     mDNSs32 reconnect_time;
 107 };
 108
 109 typedef struct {
 110         TCPListener *listener;
 111     dso_event_callback_t callback;
 112         void *context;
 113 } dso_listen_context_t;
 114
 115 void dso_transport_init(void);
 116 mStatus dso_set_connection(dso_state_t *dso, TCPSocket *socket);
 117 void dso_schedule_reconnect(mDNS *m, dso_connect_state_t *cs, mDNSs32 when);
 118 void dso_set_callback(dso_state_t *dso, void *context, dso_event_callback_t cb);
 119 mStatus dso_message_write(dso_state_t *dso, dso_message_t *msg, bool disregard_low_water);
 120 dso_connect_state_t *dso_connect_state_create(const char *host, mDNSAddr *addr, mDNSIPPort port,
 121                                               int num_outstanding_queries,
 122                                               size_t inbuf_size, size_t outbuf_size,
 123                                               dso_event_callback_t callback,
 124                                               dso_state_t *dso, void *context, const char *detail);
 125 #ifdef DSO_USES_NETWORK_FRAMEWORK
 126 void dso_connect_state_use_tls(dso_connect_state_t *cs);
 127 #endif
 128 void dso_connect_state_drop(dso_connect_state_t *cs);
 129 bool dso_connect(dso_connect_state_t *connect_state);
 130 mStatus dso_listen(dso_connect_state_t *listen_context);
 131 bool dso_write_start(dso_transport_t *transport, size_t length);
 132 bool dso_write_finish(dso_transport_t *transport);
 133 void dso_write(dso_transport_t *transport, const uint8_t *buf, size_t length);
 134 #endif // __DSO_TRANSPORT_H
 135
 136 // Local Variables:
 137 // mode: C
 138 // tab-width: 4
 139 // c-file-style: "bsd"
 140 // c-basic-offset: 4
 141 // fill-column: 108
 142 // indent-tabs-mode: nil
 143 // End: