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 #include "../lib/libwebsockets.h"
  21 #include <string.h>
  22 #include <stdlib.h>
  23
  24 /* lws-mirror_protocol */
  25
  26 #define MAX_MESSAGE_QUEUE 512
  27
  28 struct per_session_data__lws_mirror {
  29         struct lws *wsi;
  30         int ringbuffer_tail;
  31 };
  32
  33 struct a_message {
  34         void *payload;
  35         size_t len;
  36 };
  37
  38 struct per_vhost_data__lws_mirror {
  39         struct a_message ringbuffer[MAX_MESSAGE_QUEUE];
  40         int ringbuffer_head;
  41 };
  42
  43 static int
  44 callback_lws_mirror(struct lws *wsi, enum lws_callback_reasons reason,
  45                     void *user, void *in, size_t len)
  46 {
  47         struct per_session_data__lws_mirror *pss =
  48                         (struct per_session_data__lws_mirror *)user;
  49         struct per_vhost_data__lws_mirror *v =
  50                         (struct per_vhost_data__lws_mirror *)
  51                         lws_protocol_vh_priv_get(lws_vhost_get(wsi),
  52                                         lws_get_protocol(wsi));
  53         int n, m;
  54
  55         switch (reason) {
  56
  57         case LWS_CALLBACK_ESTABLISHED:
  58                 lwsl_info("%s: LWS_CALLBACK_ESTABLISHED\n", __func__);
  59                 pss->ringbuffer_tail = v->ringbuffer_head;
  60                 pss->wsi = wsi;
  61                 break;
  62
  63         case LWS_CALLBACK_PROTOCOL_INIT: /* per vhost */
  64                 lws_protocol_vh_priv_zalloc(lws_vhost_get(wsi),
  65                                 lws_get_protocol(wsi),
  66                                 sizeof(struct per_vhost_data__lws_mirror));
  67                 break;
  68
  69         case LWS_CALLBACK_PROTOCOL_DESTROY: /* per vhost */
  70                 if (!v)
  71                         break;
  72                 lwsl_info("%s: mirror protocol cleaning up %p\n", __func__, v);
  73                 for (n = 0; n < ARRAY_SIZE(v->ringbuffer); n++)
  74                         if (v->ringbuffer[n].payload) {
  75                                 free(v->ringbuffer[n].payload);
  76                                 v->ringbuffer[n].payload = NULL;
  77                         }
  78                 break;
  79
  80         case LWS_CALLBACK_SERVER_WRITEABLE:
  81                 while (pss->ringbuffer_tail != v->ringbuffer_head) {
  82                         m = v->ringbuffer[pss->ringbuffer_tail].len;
  83                         n = lws_write(wsi, (unsigned char *)
  84                                    v->ringbuffer[pss->ringbuffer_tail].payload +
  85                                    LWS_PRE, m, LWS_WRITE_TEXT);
  86                         if (n < 0) {
  87                                 lwsl_err("ERROR %d writing to mirror socket\n", n);
  88                                 return -1;
  89                         }
  90                         if (n < m)
  91                                 lwsl_err("mirror partial write %d vs %d\n", n, m);
  92
  93                         if (pss->ringbuffer_tail == (MAX_MESSAGE_QUEUE - 1))
  94                                 pss->ringbuffer_tail = 0;
  95                         else
  96                                 pss->ringbuffer_tail++;
  97
  98                         if (((v->ringbuffer_head - pss->ringbuffer_tail) &
  99                             (MAX_MESSAGE_QUEUE - 1)) == (MAX_MESSAGE_QUEUE - 15))
 100                                 lws_rx_flow_allow_all_protocol(lws_get_context(wsi),
 101                                                lws_get_protocol(wsi));
 102
 103                         if (lws_send_pipe_choked(wsi)) {
 104                                 lws_callback_on_writable(wsi);
 105                                 break;
 106                         }
 107                 }
 108                 break;
 109
 110         case LWS_CALLBACK_RECEIVE:
 111                 if (((v->ringbuffer_head - pss->ringbuffer_tail) &
 112                     (MAX_MESSAGE_QUEUE - 1)) == (MAX_MESSAGE_QUEUE - 1)) {
 113                         lwsl_err("dropping!\n");
 114                         goto choke;
 115                 }
 116
 117                 if (v->ringbuffer[v->ringbuffer_head].payload)
 118                         free(v->ringbuffer[v->ringbuffer_head].payload);
 119
 120                 v->ringbuffer[v->ringbuffer_head].payload = malloc(LWS_PRE + len);
 121                 v->ringbuffer[v->ringbuffer_head].len = len;
 122                 memcpy((char *)v->ringbuffer[v->ringbuffer_head].payload +
 123                        LWS_PRE, in, len);
 124                 if (v->ringbuffer_head == (MAX_MESSAGE_QUEUE - 1))
 125                         v->ringbuffer_head = 0;
 126                 else
 127                         v->ringbuffer_head++;
 128
 129                 if (((v->ringbuffer_head - pss->ringbuffer_tail) &
 130                     (MAX_MESSAGE_QUEUE - 1)) != (MAX_MESSAGE_QUEUE - 2))
 131                         goto done;
 132
 133 choke:
 134                 lwsl_debug("LWS_CALLBACK_RECEIVE: throttling %p\n", wsi);
 135                 lws_rx_flow_control(wsi, 0);
 136
 137 done:
 138                 lws_callback_on_writable_all_protocol(lws_get_context(wsi),
 139                                                       lws_get_protocol(wsi));
 140                 break;
 141
 142         default:
 143                 break;
 144         }
 145
 146         return 0;
 147 }
 148
 149 static const struct lws_protocols protocols[] = {
 150         {
 151                 "lws-mirror-protocol",
 152                 callback_lws_mirror,
 153                 sizeof(struct per_session_data__lws_mirror),
 154                 128, /* rx buf size must be >= permessage-deflate rx size */
 155         },
 156 };
 157
 158 LWS_VISIBLE int
 159 init_protocol_lws_mirror(struct lws_context *context,
 160                              struct lws_plugin_capability *c)
 161 {
 162         if (c->api_magic != LWS_PLUGIN_API_MAGIC) {
 163                 lwsl_err("Plugin API %d, library API %d", LWS_PLUGIN_API_MAGIC,
 164                          c->api_magic);
 165                 return 1;
 166         }
 167
 168         c->protocols = protocols;
 169         c->count_protocols = ARRAY_SIZE(protocols);
 170         c->extensions = NULL;
 171         c->count_extensions = 0;
 172
 173         return 0;
 174 }
 175
 176 LWS_VISIBLE int
 177 destroy_protocol_lws_mirror(struct lws_context *context)
 178 {
 179         return 0;
 180 }
 181