1/* 2 * libwebsockets - small server side websockets and web server implementation 3 * 4 * Copyright (C) 2010 - 2020 Andy Green <andy@warmcat.com> 5 * Sakthi Kannan <saktr@amazon.com> 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a copy 8 * of this software and associated documentation files (the "Software"), to 9 * deal in the Software without restriction, including without limitation the 10 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 11 * sell copies of the Software, and to permit persons to whom the Software is 12 * furnished to do so, subject to the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in 15 * all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 22 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 23 * IN THE SOFTWARE. 24 */ 25 26#include <private-lib-core.h> 27 28#define MQTT_CONNECT_MSG_BASE_LEN (12) 29 30struct lws * 31lws_mqtt_client_send_connect(struct lws *wsi) 32{ 33 /* static int */ 34 /* lws_mqttc_abs_writeable(lws_abs_protocol_inst_t *api, size_t budget) */ 35 const lws_mqttc_t *c = &wsi->mqtt->client; 36 uint8_t b[256 + LWS_PRE], *start = b + LWS_PRE, *p = start; 37 unsigned int len = MQTT_CONNECT_MSG_BASE_LEN; 38 39 switch (lwsi_state(wsi)) { 40 case LRS_MQTTC_IDLE: 41 /* 42 * Transport connected - this is our chance to do the 43 * protocol connect action. 44 */ 45 46 /* 1. Fixed Headers */ 47 if (lws_mqtt_fill_fixed_header(p++, LMQCP_CTOS_CONNECT, 0, 0, 0)) { 48 lwsl_err("%s: Failled to fill fixed header\n", __func__); 49 return NULL; 50 } 51 52 /* 53 * 2. Remaining length - Add the lengths of client ID, 54 * username and password and their length fields if 55 * the respective flags are set. 56 */ 57 len += c->id->len; 58 if (c->conn_flags & LMQCFT_USERNAME && c->username) { 59 len = len + (unsigned int)c->username->len + 2; 60 if (c->conn_flags & LMQCFT_PASSWORD) 61 len += (unsigned int)(c->password ? c->password->len : 0) + 2u; 62 } 63 if (c->conn_flags & LMQCFT_WILL_FLAG && c->will.topic) { 64 len = len + (unsigned int)c->will.topic->len + 2; 65 len += (c->will.message ? c->will.message->len : 0) + 2u; 66 } 67 p += lws_mqtt_vbi_encode(len, p); 68 69 /* 70 * 3. Variable Header - Protocol name & level, Connect 71 * flags and keep alive time (in secs). 72 */ 73 lws_ser_wu16be(p, 4); /* Length of protocol name */ 74 p += 2; 75 *p++ = 'M'; 76 *p++ = 'Q'; 77 *p++ = 'T'; 78 *p++ = 'T'; 79 *p++ = MQTT_VER_3_1_1; 80 *p++ = (uint8_t)c->conn_flags; 81 lws_ser_wu16be(p, c->keep_alive_secs); 82 p += 2; 83 84 /* 85 * 4. Payload - Client ID, Will topic & message, 86 * Username & password. 87 */ 88 if (lws_mqtt_str_is_not_empty(c->id)) { 89 lws_ser_wu16be(p, c->id->len); 90 p += 2; 91 memcpy(p, c->id->buf, c->id->len); 92 p += c->id->len; 93 } else { 94 /* 95 * If the Client supplies a zero-byte 96 * ClientId, the Client MUST also set 97 * CleanSession to 1 [MQTT-3.1.3-7]. 98 */ 99 if (!(c->conn_flags & LMQCFT_CLEAN_START)) { 100 lwsl_err("%s: Empty client ID needs a clean start\n", 101 __func__); 102 return NULL; 103 } 104 *p++ = 0; 105 } 106 107 if (c->conn_flags & LMQCFT_WILL_FLAG) { 108 if (lws_mqtt_str_is_not_empty(c->will.topic)) { 109 lws_ser_wu16be(p, c->will.topic->len); 110 p += 2; 111 memcpy(p, c->will.topic->buf, c->will.topic->len); 112 p += c->will.topic->len; 113 if (lws_mqtt_str_is_not_empty(c->will.message)) { 114 lws_ser_wu16be(p, c->will.message->len); 115 p += 2; 116 memcpy(p, c->will.message->buf, 117 c->will.message->len); 118 p += c->will.message->len; 119 } else { 120 lws_ser_wu16be(p, 0); 121 p += 2; 122 } 123 } else { 124 lwsl_err("%s: Missing Will Topic\n", __func__); 125 return NULL; 126 } 127 } 128 if (c->conn_flags & LMQCFT_USERNAME) { 129 /* 130 * Detailed sanity check on the username and 131 * password strings. 132 */ 133 if (lws_mqtt_str_is_not_empty(c->username)) { 134 lws_ser_wu16be(p, c->username->len); 135 p += 2; 136 memcpy(p, c->username->buf, c->username->len); 137 p += c->username->len; 138 } else { 139 lwsl_err("%s: Empty / missing Username!\n", 140 __func__); 141 return NULL; 142 } 143 if (c->conn_flags & LMQCFT_PASSWORD) { 144 if (lws_mqtt_str_is_not_empty(c->password)) { 145 lws_ser_wu16be(p, c->password->len); 146 p += 2; 147 memcpy(p, c->password->buf, 148 c->password->len); 149 p += c->password->len; 150 } else { 151 lws_ser_wu16be(p, 0); 152 p += 2; 153 } 154 } 155 } else if (c->conn_flags & LMQCFT_PASSWORD) { 156 lwsl_err("%s: Unsupported - Password without username\n", 157 __func__); 158 return NULL; 159 } 160 break; 161 default: 162 lwsl_err("%s: unexpected state %d\n", __func__, lwsi_state(wsi)); 163 164 return NULL; 165 } 166 167 /* 168 * Perform the actual write 169 */ 170 if (lws_write(wsi, (unsigned char *)&b[LWS_PRE], lws_ptr_diff_size_t(p, start), 171 LWS_WRITE_BINARY) != lws_ptr_diff(p, start)) { 172 lwsl_notice("%s: write failed\n", __func__); 173 174 return NULL; 175 } 176 177 return wsi; 178} 179 180struct lws * 181lws_mqtt_client_send_disconnect(struct lws *wsi) 182{ 183 uint8_t b[256 + LWS_PRE], *start = b + LWS_PRE, *p = start; 184 185 /* 1. Fixed Headers */ 186 if (lws_mqtt_fill_fixed_header(p++, LMQCP_DISCONNECT, 0, 0, 0)) 187 { 188 lwsl_err("%s: Failled to fill fixed header\n", __func__); 189 return NULL; 190 } 191 *p++ = 0; 192 if (lws_write(wsi, (unsigned char *)&b[LWS_PRE], lws_ptr_diff_size_t(p, start), 193 LWS_WRITE_BINARY) != lws_ptr_diff(p, start)) { 194 lwsl_err("%s: write failed\n", __func__); 195 196 return NULL; 197 } 198 199 return wsi; 200} 201