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
  21 #if !defined (LWS_PLUGIN_STATIC)
  22 #define LWS_DLL
  23 #define LWS_INTERNAL
  24 #include "../lib/libwebsockets.h"
  25 #endif
  26
  27 #include <string.h>
  28 #include <stdlib.h>
  29
  30 /* lws-mirror_protocol */
  31
  32 #if defined(LWS_WITH_ESP8266)
  33 #define MAX_MESSAGE_QUEUE 64
  34 #else
  35 #define MAX_MESSAGE_QUEUE 512
  36 #endif
  37
  38 #define MAX_MIRROR_INSTANCES 10
  39
  40 struct lws_mirror_instance;
  41
  42 struct per_session_data__lws_mirror {
  43         struct lws *wsi;
  44         struct lws_mirror_instance *mi;
  45         struct per_session_data__lws_mirror *same_mi_pss_list;
  46         int ringbuffer_tail;
  47 };
  48
  49 struct a_message {
  50         void *payload;
  51         size_t len;
  52 };
  53
  54 struct lws_mirror_instance {
  55         struct lws_mirror_instance *next;
  56         struct per_session_data__lws_mirror *same_mi_pss_list;
  57         char name[30];
  58         struct a_message ringbuffer[MAX_MESSAGE_QUEUE];
  59         int ringbuffer_head;
  60 };
  61
  62 struct per_vhost_data__lws_mirror {
  63         struct lws_mirror_instance *mi_list;
  64 };
  65
  66 static int
  67 callback_lws_mirror(struct lws *wsi, enum lws_callback_reasons reason,
  68                     void *user, void *in, size_t len)
  69 {
  70         struct per_session_data__lws_mirror *pss =
  71                         (struct per_session_data__lws_mirror *)user, **ppss,
  72                         *pss1;
  73         struct per_vhost_data__lws_mirror *v =
  74                         (struct per_vhost_data__lws_mirror *)
  75                         lws_protocol_vh_priv_get(lws_get_vhost(wsi),
  76                                         lws_get_protocol(wsi));
  77         struct lws_mirror_instance *mi, **pmi;
  78         char name[30];
  79         int n, m, count_mi = 0;
  80
  81         switch (reason) {
  82
  83         case LWS_CALLBACK_ESTABLISHED:
  84                 lwsl_info("%s: LWS_CALLBACK_ESTABLISHED\n", __func__);
  85
  86                 /*
  87                  * mirror instance name... defaults to "", but if URL includes
  88                  * "?mirror=xxx", will be "xxx"
  89                  */
  90
  91                 name[0] = '\0';
  92                 lws_get_urlarg_by_name(wsi, "mirror", name, sizeof(name) - 1);
  93
  94                 lwsl_notice("mirror %s\n", name);
  95
  96                 /* is there already a mirror instance of this name? */
  97
  98                 mi = v->mi_list;
  99                 while (mi) {
 100                         if (!strcmp(name, mi->name)) {
 101                                 lwsl_notice("Joining existing mi %p '%s'\n",
 102                                                 mi, name);
 103                                 /* yes... we will join it */
 104                                 break;
 105                         }
 106                         count_mi++;
 107                         mi = mi->next;
 108                 }
 109
 110                 if (!mi) {
 111
 112                         /* no existing mirror instance for name */
 113
 114                         if (count_mi == MAX_MIRROR_INSTANCES)
 115                                 return -1;
 116
 117                         /* create one with this name, and join it */
 118
 119                         mi = malloc(sizeof(*mi));
 120                         memset(mi, 0, sizeof(*mi));
 121                         mi->next = v->mi_list;
 122                         v->mi_list = mi;
 123                         strcpy(mi->name, name);
 124                         mi->ringbuffer_head = 0;
 125
 126
 127                         lwsl_notice("Created new mi %p '%s'\n", mi, name);
 128                 }
 129
 130                 /* add our pss to list of guys bound to this mi */
 131
 132                 pss->same_mi_pss_list = mi->same_mi_pss_list;
 133                 mi->same_mi_pss_list = pss;
 134
 135                 /* init the pss */
 136
 137                 pss->mi = mi;
 138                 pss->ringbuffer_tail = mi->ringbuffer_head;
 139                 pss->wsi = wsi;
 140
 141                 break;
 142
 143         case LWS_CALLBACK_CLOSED:
 144
 145                 /* detach our pss from the mirror instance */
 146
 147                 mi = pss->mi;
 148                 if (!mi)
 149                         break;
 150                 ppss = &mi->same_mi_pss_list;
 151
 152                 while (*ppss) {
 153                         if (*ppss == pss) {
 154                                 *ppss = pss->same_mi_pss_list;
 155                                 break;
 156                         }
 157
 158                         ppss = &(*ppss)->same_mi_pss_list;
 159                 }
 160
 161                 if (!mi->same_mi_pss_list) {
 162
 163                         /* last pss unbound from mi... delete mi */
 164
 165                         pmi = &v->mi_list;
 166                         while (*pmi) {
 167                                 if (*pmi == mi) {
 168                                         *pmi = (*pmi)->next;
 169
 170                                         if (!pss->mi)
 171                                                 break;
 172                                         lwsl_info("%s: mirror protocol cleaning up %p\n", __func__, v);
 173                                         for (n = 0; n < ARRAY_SIZE(pss->mi->ringbuffer); n++)
 174                                                 if (pss->mi->ringbuffer[n].payload) {
 175                                                         free(pss->mi->ringbuffer[n].payload);
 176                                                         pss->mi->ringbuffer[n].payload = NULL;
 177                                                 }
 178
 179                                         free(mi);
 180                                         break;
 181                                 }
 182                                 count_mi++;
 183                                 pmi = &(*pmi)->next;
 184                         }
 185                 }
 186
 187                 break;
 188
 189         case LWS_CALLBACK_PROTOCOL_INIT: /* per vhost */
 190                 lws_protocol_vh_priv_zalloc(lws_get_vhost(wsi),
 191                                 lws_get_protocol(wsi),
 192                                 sizeof(struct per_vhost_data__lws_mirror));
 193                 break;
 194
 195         case LWS_CALLBACK_PROTOCOL_DESTROY: /* per vhost */
 196                 break;
 197
 198         case LWS_CALLBACK_SERVER_WRITEABLE:
 199                 while (pss->ringbuffer_tail != pss->mi->ringbuffer_head) {
 200                         m = pss->mi->ringbuffer[pss->ringbuffer_tail].len;
 201                         n = lws_write(wsi, (unsigned char *)
 202                                         pss->mi->ringbuffer[pss->ringbuffer_tail].payload +
 203                                    LWS_PRE, m, LWS_WRITE_TEXT);
 204                         if (n < 0) {
 205                                 lwsl_err("ERROR %d writing to mirror socket\n", n);
 206                                 return -1;
 207                         }
 208                         if (n < m)
 209                                 lwsl_err("mirror partial write %d vs %d\n", n, m);
 210
 211                         if (pss->ringbuffer_tail == (MAX_MESSAGE_QUEUE - 1))
 212                                 pss->ringbuffer_tail = 0;
 213                         else
 214                                 pss->ringbuffer_tail++;
 215
 216                         if (((pss->mi->ringbuffer_head - pss->ringbuffer_tail) &
 217                             (MAX_MESSAGE_QUEUE - 1)) == (MAX_MESSAGE_QUEUE - 15))
 218                                 lws_rx_flow_allow_all_protocol(lws_get_context(wsi),
 219                                                lws_get_protocol(wsi));
 220
 221                         if (lws_send_pipe_choked(wsi)) {
 222                                 lws_callback_on_writable(wsi);
 223                                 break;
 224                         }
 225                 }
 226                 break;
 227
 228         case LWS_CALLBACK_RECEIVE:
 229                 if (((pss->mi->ringbuffer_head - pss->ringbuffer_tail) &
 230                     (MAX_MESSAGE_QUEUE - 1)) == (MAX_MESSAGE_QUEUE - 1)) {
 231                         lwsl_err("dropping!\n");
 232                         goto choke;
 233                 }
 234
 235                 if (pss->mi->ringbuffer[pss->mi->ringbuffer_head].payload)
 236                         free(pss->mi->ringbuffer[pss->mi->ringbuffer_head].payload);
 237
 238                 pss->mi->ringbuffer[pss->mi->ringbuffer_head].payload = malloc(LWS_PRE + len);
 239                 pss->mi->ringbuffer[pss->mi->ringbuffer_head].len = len;
 240                 memcpy((char *)pss->mi->ringbuffer[pss->mi->ringbuffer_head].payload +
 241                        LWS_PRE, in, len);
 242                 if (pss->mi->ringbuffer_head == (MAX_MESSAGE_QUEUE - 1))
 243                         pss->mi->ringbuffer_head = 0;
 244                 else
 245                         pss->mi->ringbuffer_head++;
 246
 247                 if (((pss->mi->ringbuffer_head - pss->ringbuffer_tail) &
 248                     (MAX_MESSAGE_QUEUE - 1)) != (MAX_MESSAGE_QUEUE - 2))
 249                         goto done;
 250
 251 choke:
 252                 lwsl_debug("LWS_CALLBACK_RECEIVE: throttling %p\n", wsi);
 253                 lws_rx_flow_control(wsi, 0);
 254
 255 done:
 256                 /*
 257                  *  ask for WRITABLE callback for every wsi bound to this
 258                  * mirror instance
 259                  */
 260
 261                 pss1 = pss->mi->same_mi_pss_list;
 262                 while (pss1) {
 263                         lws_callback_on_writable(pss1->wsi);
 264                         pss1 = pss1->same_mi_pss_list;
 265                 }
 266                 break;
 267
 268         default:
 269                 break;
 270         }
 271
 272         return 0;
 273 }
 274
 275 #define LWS_PLUGIN_PROTOCOL_MIRROR { \
 276                 "lws-mirror-protocol", \
 277                 callback_lws_mirror, \
 278                 sizeof(struct per_session_data__lws_mirror), \
 279                 128, /* rx buf size must be >= permessage-deflate rx size */ \
 280         }
 281
 282 #if !defined (LWS_PLUGIN_STATIC)
 283
 284 static const struct lws_protocols protocols[] = {
 285         LWS_PLUGIN_PROTOCOL_MIRROR
 286 };
 287
 288 LWS_EXTERN LWS_VISIBLE int
 289 init_protocol_lws_mirror(struct lws_context *context,
 290                              struct lws_plugin_capability *c)
 291 {
 292         if (c->api_magic != LWS_PLUGIN_API_MAGIC) {
 293                 lwsl_err("Plugin API %d, library API %d", LWS_PLUGIN_API_MAGIC,
 294                          c->api_magic);
 295                 return 1;
 296         }
 297
 298         c->protocols = protocols;
 299         c->count_protocols = ARRAY_SIZE(protocols);
 300         c->extensions = NULL;
 301         c->count_extensions = 0;
 302
 303         return 0;
 304 }
 305
 306 LWS_EXTERN LWS_VISIBLE int
 307 destroy_protocol_lws_mirror(struct lws_context *context)
 308 {
 309         return 0;
 310 }
 311 #endif