plugins/protocol_lws_mirror.c

   1 /*
   2  * libwebsockets-test-server - libwebsockets test implementation
   3  *
   4  * Copyright (C) 2010-2016 Andy Green <andy@warmcat.com>
   5  *
   6  * This file is made available under the Creative Commons CC0 1.0
   7  * Universal Public Domain Dedication.
   8  *
   9  * The person who associated a work with this deed has dedicated
  10  * the work to the public domain by waiving all of his or her rights
  11  * to the work worldwide under copyright law, including all related
  12  * and neighboring rights, to the extent allowed by law. You can copy,
  13  * modify, distribute and perform the work, even for commercial purposes,
  14  * all without asking permission.
  15  *
  16  * The test apps are intended to be adapted for use in your code, which
  17  * may be proprietary.  So unlike the library itself, they are licensed
  18  * Public Domain.
  19  */
  20 #define LWS_DLL
  21 #define LWS_INTERNAL
  22 #include "../lib/libwebsockets.h"
  23 #include <string.h>
  24 #include <stdlib.h>
  25
  26 /* lws-mirror_protocol */
  27
  28 #define MAX_MESSAGE_QUEUE 512
  29
  30 struct per_session_data__lws_mirror {
  31         struct lws *wsi;
  32         int ringbuffer_tail;
  33 };
  34
  35 struct a_message {
  36         void *payload;
  37         size_t len;
  38 };
  39
  40 struct per_vhost_data__lws_mirror {
  41         struct a_message ringbuffer[MAX_MESSAGE_QUEUE];
  42         int ringbuffer_head;
  43 };
  44
  45 static int
  46 callback_lws_mirror(struct lws *wsi, enum lws_callback_reasons reason,
  47                     void *user, void *in, size_t len)
  48 {
  49         struct per_session_data__lws_mirror *pss =
  50                         (struct per_session_data__lws_mirror *)user;
  51         struct per_vhost_data__lws_mirror *v =
  52                         (struct per_vhost_data__lws_mirror *)
  53                         lws_protocol_vh_priv_get(lws_get_vhost(wsi),
  54                                         lws_get_protocol(wsi));
  55         int n, m;
  56
  57         switch (reason) {
  58
  59         case LWS_CALLBACK_ESTABLISHED:
  60                 lwsl_info("%s: LWS_CALLBACK_ESTABLISHED\n", __func__);
  61                 pss->ringbuffer_tail = v->ringbuffer_head;
  62                 pss->wsi = wsi;
  63                 break;
  64
  65         case LWS_CALLBACK_PROTOCOL_INIT: /* per vhost */
  66                 lws_protocol_vh_priv_zalloc(lws_get_vhost(wsi),
  67                                 lws_get_protocol(wsi),
  68                                 sizeof(struct per_vhost_data__lws_mirror));
  69                 break;
  70
  71         case LWS_CALLBACK_PROTOCOL_DESTROY: /* per vhost */
  72                 if (!v)
  73                         break;
  74                 lwsl_info("%s: mirror protocol cleaning up %p\n", __func__, v);
  75                 for (n = 0; n < ARRAY_SIZE(v->ringbuffer); n++)
  76                         if (v->ringbuffer[n].payload) {
  77                                 free(v->ringbuffer[n].payload);
  78                                 v->ringbuffer[n].payload = NULL;
  79                         }
  80                 break;
  81
  82         case LWS_CALLBACK_SERVER_WRITEABLE:
  83                 while (pss->ringbuffer_tail != v->ringbuffer_head) {
  84                         m = v->ringbuffer[pss->ringbuffer_tail].len;
  85                         n = lws_write(wsi, (unsigned char *)
  86                                    v->ringbuffer[pss->ringbuffer_tail].payload +
  87                                    LWS_PRE, m, LWS_WRITE_TEXT);
  88                         if (n < 0) {
  89                                 lwsl_err("ERROR %d writing to mirror socket\n", n);
  90                                 return -1;
  91                         }
  92                         if (n < m)
  93                                 lwsl_err("mirror partial write %d vs %d\n", n, m);
  94
  95                         if (pss->ringbuffer_tail == (MAX_MESSAGE_QUEUE - 1))
  96                                 pss->ringbuffer_tail = 0;
  97                         else
  98                                 pss->ringbuffer_tail++;
  99
 100                         if (((v->ringbuffer_head - pss->ringbuffer_tail) &
 101                             (MAX_MESSAGE_QUEUE - 1)) == (MAX_MESSAGE_QUEUE - 15))
 102                                 lws_rx_flow_allow_all_protocol(lws_get_context(wsi),
 103                                                lws_get_protocol(wsi));
 104
 105                         if (lws_send_pipe_choked(wsi)) {
 106                                 lws_callback_on_writable(wsi);
 107                                 break;
 108                         }
 109                 }
 110                 break;
 111
 112         case LWS_CALLBACK_RECEIVE:
 113                 if (((v->ringbuffer_head - pss->ringbuffer_tail) &
 114                     (MAX_MESSAGE_QUEUE - 1)) == (MAX_MESSAGE_QUEUE - 1)) {
 115                         lwsl_err("dropping!\n");
 116                         goto choke;
 117                 }
 118
 119                 if (v->ringbuffer[v->ringbuffer_head].payload)
 120                         free(v->ringbuffer[v->ringbuffer_head].payload);
 121
 122                 v->ringbuffer[v->ringbuffer_head].payload = malloc(LWS_PRE + len);
 123                 v->ringbuffer[v->ringbuffer_head].len = len;
 124                 memcpy((char *)v->ringbuffer[v->ringbuffer_head].payload +
 125                        LWS_PRE, in, len);
 126                 if (v->ringbuffer_head == (MAX_MESSAGE_QUEUE - 1))
 127                         v->ringbuffer_head = 0;
 128                 else
 129                         v->ringbuffer_head++;
 130
 131                 if (((v->ringbuffer_head - pss->ringbuffer_tail) &
 132                     (MAX_MESSAGE_QUEUE - 1)) != (MAX_MESSAGE_QUEUE - 2))
 133                         goto done;
 134
 135 choke:
 136                 lwsl_debug("LWS_CALLBACK_RECEIVE: throttling %p\n", wsi);
 137                 lws_rx_flow_control(wsi, 0);
 138
 139 done:
 140                 lws_callback_on_writable_all_protocol(lws_get_context(wsi),
 141                                                       lws_get_protocol(wsi));
 142                 break;
 143
 144         default:
 145                 break;
 146         }
 147
 148         return 0;
 149 }
 150
 151 static const struct lws_protocols protocols[] = {
 152         {
 153                 "lws-mirror-protocol",
 154                 callback_lws_mirror,
 155                 sizeof(struct per_session_data__lws_mirror),
 156                 128, /* rx buf size must be >= permessage-deflate rx size */
 157         },
 158 };
 159
 160 LWS_EXTERN LWS_VISIBLE int
 161 init_protocol_lws_mirror(struct lws_context *context,
 162                              struct lws_plugin_capability *c)
 163 {
 164         if (c->api_magic != LWS_PLUGIN_API_MAGIC) {
 165                 lwsl_err("Plugin API %d, library API %d", LWS_PLUGIN_API_MAGIC,
 166                          c->api_magic);
 167                 return 1;
 168         }
 169
 170         c->protocols = protocols;
 171         c->count_protocols = ARRAY_SIZE(protocols);
 172         c->extensions = NULL;
 173         c->count_extensions = 0;
 174
 175         return 0;
 176 }
 177
 178 LWS_EXTERN LWS_VISIBLE int
 179 destroy_protocol_lws_mirror(struct lws_context *context)
 180 {
 181         return 0;
 182 }
 183