test-server/test-server-mirror.c

   1 /*
   2  * libwebsockets-test-server - libwebsockets test implementation
   3  *
   4  * Copyright (C) 2010-2015 Andy Green <andy@warmcat.com>
   5  *
   6  *  This library is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU Lesser General Public
   8  *  License as published by the Free Software Foundation:
   9  *  version 2.1 of the License.
  10  *
  11  *  This library is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *  Lesser General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU Lesser General Public
  17  *  License along with this library; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  19  *  MA  02110-1301  USA
  20  */
  21 #include "test-server.h"
  22
  23 /* lws-mirror_protocol */
  24
  25 #define MAX_MESSAGE_QUEUE 512
  26
  27 struct a_message {
  28         void *payload;
  29         size_t len;
  30 };
  31
  32 static struct a_message ringbuffer[MAX_MESSAGE_QUEUE];
  33 static int ringbuffer_head;
  34
  35 int
  36 callback_lws_mirror(struct lws *wsi, enum lws_callback_reasons reason,
  37                     void *user, void *in, size_t len)
  38 {
  39         struct per_session_data__lws_mirror *pss =
  40                         (struct per_session_data__lws_mirror *)user;
  41         int n, m;
  42
  43         switch (reason) {
  44
  45         case LWS_CALLBACK_ESTABLISHED:
  46                 lwsl_info("%s: LWS_CALLBACK_ESTABLISHED\n", __func__);
  47                 pss->ringbuffer_tail = ringbuffer_head;
  48                 pss->wsi = wsi;
  49                 break;
  50
  51         case LWS_CALLBACK_PROTOCOL_DESTROY:
  52                 lwsl_notice("%s: mirror protocol cleaning up\n", __func__);
  53                 for (n = 0; n < sizeof ringbuffer / sizeof ringbuffer[0]; n++)
  54                         if (ringbuffer[n].payload)
  55                                 free(ringbuffer[n].payload);
  56                 break;
  57
  58         case LWS_CALLBACK_SERVER_WRITEABLE:
  59                 if (close_testing)
  60                         break;
  61                 while (pss->ringbuffer_tail != ringbuffer_head) {
  62                         m = ringbuffer[pss->ringbuffer_tail].len;
  63                         n = lws_write(wsi, (unsigned char *)
  64                                    ringbuffer[pss->ringbuffer_tail].payload +
  65                                    LWS_PRE, m, LWS_WRITE_TEXT);
  66                         if (n < 0) {
  67                                 lwsl_err("ERROR %d writing to mirror socket\n", n);
  68                                 return -1;
  69                         }
  70                         if (n < m)
  71                                 lwsl_err("mirror partial write %d vs %d\n", n, m);
  72
  73                         if (pss->ringbuffer_tail == (MAX_MESSAGE_QUEUE - 1))
  74                                 pss->ringbuffer_tail = 0;
  75                         else
  76                                 pss->ringbuffer_tail++;
  77
  78                         if (((ringbuffer_head - pss->ringbuffer_tail) &
  79                             (MAX_MESSAGE_QUEUE - 1)) == (MAX_MESSAGE_QUEUE - 15))
  80                                 lws_rx_flow_allow_all_protocol(lws_get_context(wsi),
  81                                                lws_get_protocol(wsi));
  82
  83                         if (lws_send_pipe_choked(wsi)) {
  84                                 lws_callback_on_writable(wsi);
  85                                 break;
  86                         }
  87                 }
  88                 break;
  89
  90         case LWS_CALLBACK_RECEIVE:
  91                 if (((ringbuffer_head - pss->ringbuffer_tail) &
  92                     (MAX_MESSAGE_QUEUE - 1)) == (MAX_MESSAGE_QUEUE - 1)) {
  93                         lwsl_err("dropping!\n");
  94                         goto choke;
  95                 }
  96
  97                 if (ringbuffer[ringbuffer_head].payload)
  98                         free(ringbuffer[ringbuffer_head].payload);
  99
 100                 ringbuffer[ringbuffer_head].payload = malloc(LWS_PRE + len);
 101                 ringbuffer[ringbuffer_head].len = len;
 102                 memcpy((char *)ringbuffer[ringbuffer_head].payload +
 103                        LWS_PRE, in, len);
 104                 if (ringbuffer_head == (MAX_MESSAGE_QUEUE - 1))
 105                         ringbuffer_head = 0;
 106                 else
 107                         ringbuffer_head++;
 108
 109                 if (((ringbuffer_head - pss->ringbuffer_tail) &
 110                     (MAX_MESSAGE_QUEUE - 1)) != (MAX_MESSAGE_QUEUE - 2))
 111                         goto done;
 112
 113 choke:
 114                 lwsl_debug("LWS_CALLBACK_RECEIVE: throttling %p\n", wsi);
 115                 lws_rx_flow_control(wsi, 0);
 116
 117 done:
 118                 lws_callback_on_writable_all_protocol(lws_get_context(wsi),
 119                                                       lws_get_protocol(wsi));
 120                 break;
 121
 122         /*
 123          * this just demonstrates how to use the protocol filter. If you won't
 124          * study and reject connections based on header content, you don't need
 125          * to handle this callback
 126          */
 127
 128         case LWS_CALLBACK_FILTER_PROTOCOL_CONNECTION:
 129                 dump_handshake_info(wsi);
 130                 /* you could return non-zero here and kill the connection */
 131                 break;
 132
 133         default:
 134                 break;
 135         }
 136
 137         return 0;
 138 }