1 /*
2 * ws protocol handler plugin for "lws-minimal-pmd-bulk"
3 *
4 * Written in 2010-2019 by 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 protocol shows how to send and receive bulk messages over a ws connection
10 * that optionally may have the permessage-deflate extension negotiated on it.
11 */
12
13 #if !defined (LWS_PLUGIN_STATIC)
14 #define LWS_DLL
15 #define LWS_INTERNAL
16 #include <libwebsockets.h>
17 #endif
18
19 #include <string.h>
20
21 /*
22 * We will produce a large ws message either from this text repeated many times,
23 * or from 0x40 + a 6-bit pseudorandom number
24 */
25
26 static const char * const redundant_string =
27 "No one would have believed in the last years of the nineteenth "
28 "century that this world was being watched keenly and closely by "
29 "intelligences greater than man's and yet as mortal as his own; that as "
30 "men busied themselves about their various concerns they were "
31 "scrutinised and studied, perhaps almost as narrowly as a man with a "
32 "microscope might scrutinise the transient creatures that swarm and "
33 "multiply in a drop of water. With infinite complacency men went to "
34 "and fro over this globe about their little affairs, serene in their "
35 "assurance of their empire over matter. It is possible that the "
36 "infusoria under the microscope do the same. No one gave a thought to "
37 "the older worlds of space as sources of human danger, or thought of "
38 "them only to dismiss the idea of life upon them as impossible or "
39 "improbable. It is curious to recall some of the mental habits of "
40 "those departed days. At most terrestrial men fancied there might be "
41 "other men upon Mars, perhaps inferior to themselves and ready to "
42 "welcome a missionary enterprise. Yet across the gulf of space, minds "
43 "that are to our minds as ours are to those of the beasts that perish, "
44 "intellects vast and cool and unsympathetic, regarded this earth with "
45 "envious eyes, and slowly and surely drew their plans against us. And "
46 "early in the twentieth century came the great disillusionment. "
47 ;
48
49 /* this reflects the length of the string above */
50 #define REPEAT_STRING_LEN 1337
51 /* this is the total size of the ws message we will send */
52 #define MESSAGE_SIZE (100 * REPEAT_STRING_LEN)
53 /* this is how much we will send each time the connection is writable */
54 #define MESSAGE_CHUNK_SIZE (1 * 1024)
55
56 /* one of these is created for each client connecting to us */
57
58 struct per_session_data__minimal_pmd_bulk {
59 int position_tx, position_rx;
60 uint64_t rng_rx, rng_tx;
61 };
62
63 struct vhd_minimal_pmd_bulk {
64 int *interrupted;
65 /*
66 * b0 = 1: test compressible text, = 0: test uncompressible binary
67 * b1 = 1: send as a single blob, = 0: send as fragments
68 */
69 int *options;
70 };
71
rng(uint64_t * r)72 static uint64_t rng(uint64_t *r)
73 {
74 *r ^= *r << 21;
75 *r ^= *r >> 35;
76 *r ^= *r << 4;
77
78 return *r;
79 }
80
81 static int
callback_minimal_pmd_bulk(struct lws * wsi,enum lws_callback_reasons reason,void * user,void * in,size_t len)82 callback_minimal_pmd_bulk(struct lws *wsi, enum lws_callback_reasons reason,
83 void *user, void *in, size_t len)
84 {
85 struct per_session_data__minimal_pmd_bulk *pss =
86 (struct per_session_data__minimal_pmd_bulk *)user;
87 struct vhd_minimal_pmd_bulk *vhd = (struct vhd_minimal_pmd_bulk *)
88 lws_protocol_vh_priv_get(lws_get_vhost(wsi),
89 lws_get_protocol(wsi));
90 uint8_t buf[LWS_PRE + MESSAGE_SIZE], *start = &buf[LWS_PRE], *p;
91 int n, m, flags, olen, amount;
92
93 switch (reason) {
94 case LWS_CALLBACK_PROTOCOL_INIT:
95 vhd = lws_protocol_vh_priv_zalloc(lws_get_vhost(wsi),
96 lws_get_protocol(wsi),
97 sizeof(struct vhd_minimal_pmd_bulk));
98 if (!vhd)
99 return -1;
100
101 /* get the pointer to "interrupted" we were passed in pvo */
102 vhd->interrupted = (int *)lws_pvo_search(
103 (const struct lws_protocol_vhost_options *)in,
104 "interrupted")->value;
105 vhd->options = (int *)lws_pvo_search(
106 (const struct lws_protocol_vhost_options *)in,
107 "options")->value;
108 break;
109
110 case LWS_CALLBACK_ESTABLISHED:
111 pss->rng_tx = 4;
112 pss->rng_rx = 4;
113 lws_callback_on_writable(wsi);
114 break;
115
116 case LWS_CALLBACK_SERVER_WRITEABLE:
117 if (pss->position_tx == MESSAGE_SIZE)
118 break;
119
120 amount = MESSAGE_CHUNK_SIZE;
121 if ((*vhd->options) & 2) {
122 amount = MESSAGE_SIZE;
123 lwsl_user("(writing as one blob of %d)\n", amount);
124 }
125
126 /* fill up one chunk's worth of message content */
127
128 p = start;
129 n = amount;
130 if (n > MESSAGE_SIZE - pss->position_tx)
131 n = MESSAGE_SIZE - pss->position_tx;
132
133 flags = lws_write_ws_flags(LWS_WRITE_BINARY, !pss->position_tx,
134 pss->position_tx + n == MESSAGE_SIZE);
135
136 /*
137 * select between producing compressible repeated text,
138 * or uncompressible PRNG output
139 */
140
141 if (*vhd->options & 1) {
142 while (n) {
143 size_t s;
144
145 m = pss->position_tx % REPEAT_STRING_LEN;
146 s = REPEAT_STRING_LEN - m;
147 if (s > (size_t)n)
148 s = n;
149 memcpy(p, &redundant_string[m], s);
150 pss->position_tx += s;
151 p += s;
152 n -= s;
153 }
154 } else {
155 pss->position_tx += n;
156 while (n--)
157 *p++ = rng(&pss->rng_tx);
158 }
159
160 n = lws_ptr_diff(p, start);
161 m = lws_write(wsi, start, n, flags);
162 lwsl_user("LWS_CALLBACK_SERVER_WRITEABLE: wrote %d\n", n);
163 if (m < n) {
164 lwsl_err("ERROR %d / %d writing ws\n", m, n);
165 return -1;
166 }
167 if (pss->position_tx != MESSAGE_SIZE) /* if more to do... */
168 lws_callback_on_writable(wsi);
169 break;
170
171 case LWS_CALLBACK_RECEIVE:
172 lwsl_user("LWS_CALLBACK_RECEIVE: %4d (pss->pos=%d, rpp %5d, last %d)\n",
173 (int)len, (int)pss->position_rx, (int)lws_remaining_packet_payload(wsi),
174 lws_is_final_fragment(wsi));
175 olen = len;
176
177 if (*vhd->options & 1) {
178 while (len) {
179 size_t s;
180 m = pss->position_rx % REPEAT_STRING_LEN;
181 s = REPEAT_STRING_LEN - m;
182 if (s > len)
183 s = len;
184 if (memcmp(in, &redundant_string[m], s)) {
185 lwsl_user("echo'd data doesn't match\n");
186 return -1;
187 }
188 pss->position_rx += s;
189 in = ((char *)in) + s;
190 len -= s;
191 }
192 } else {
193 p = (uint8_t *)in;
194 pss->position_rx += len;
195 while (len--) {
196 if (*p++ != (uint8_t)rng(&pss->rng_rx)) {
197 lwsl_user("echo'd data doesn't match: 0x%02X 0x%02X (%d)\n",
198 *(p - 1), (int)(0x40 + (pss->rng_rx & 0x3f)),
199 (int)((pss->position_rx - olen) + olen - len));
200 lwsl_hexdump_notice(in, olen);
201 return -1;
202 }
203 }
204 if (pss->position_rx == MESSAGE_SIZE)
205 pss->position_rx = 0;
206 }
207 break;
208
209 default:
210 break;
211 }
212
213 return 0;
214 }
215
216 #define LWS_PLUGIN_PROTOCOL_MINIMAL_PMD_BULK \
217 { \
218 "lws-minimal-pmd-bulk", \
219 callback_minimal_pmd_bulk, \
220 sizeof(struct per_session_data__minimal_pmd_bulk), \
221 4096, \
222 0, NULL, 0 \
223 }
224
225 #if !defined (LWS_PLUGIN_STATIC)
226
227 /* boilerplate needed if we are built as a dynamic plugin */
228
229 static const struct lws_protocols protocols[] = {
230 LWS_PLUGIN_PROTOCOL_MINIMAL_PMD_BULK
231 };
232
233 int
init_protocol_minimal_pmd_bulk(struct lws_context * context,struct lws_plugin_capability * c)234 init_protocol_minimal_pmd_bulk(struct lws_context *context,
235 struct lws_plugin_capability *c)
236 {
237 if (c->api_magic != LWS_PLUGIN_API_MAGIC) {
238 lwsl_err("Plugin API %d, library API %d", LWS_PLUGIN_API_MAGIC,
239 c->api_magic);
240 return 1;
241 }
242
243 c->protocols = protocols;
244 c->count_protocols = LWS_ARRAY_SIZE(protocols);
245 c->extensions = NULL;
246 c->count_extensions = 0;
247
248 return 0;
249 }
250
251 int
destroy_protocol_minimal_pmd_bulk(struct lws_context * context)252 destroy_protocol_minimal_pmd_bulk(struct lws_context *context)
253 {
254 return 0;
255 }
256 #endif
257