libjaylink/discovery_tcp.c

   1 /*
   2  * This file is part of the libjaylink project.
   3  *
   4  * Copyright (C) 2015-2017 Marc Schink <jaylink-dev@marcschink.de>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdlib.h>
  21 #include <stdint.h>
  22 #include <string.h>
  23 #include <ctype.h>
  24 #ifdef _WIN32
  25 #include <winsock2.h>
  26 #else
  27 #include <sys/types.h>
  28 #include <sys/socket.h>
  29 #include <netinet/in.h>
  30 #include <arpa/inet.h>
  31 #endif
  32
  33 #include "libjaylink.h"
  34 #include "libjaylink-internal.h"
  35
  36 /**
  37  * @file
  38  *
  39  * Device discovery (TCP/IP).
  40  */
  41
  42 /** @cond PRIVATE */
  43 /** Size of the advertisement message in bytes. */
  44 #define ADV_MESSAGE_SIZE        128
  45
  46 /** Device discovery port number. */
  47 #define DISC_PORT               19020
  48
  49 /** Size of the discovery message in bytes. */
  50 #define DISC_MESSAGE_SIZE       64
  51
  52 /** Discovery timeout in milliseconds. */
  53 #define DISC_TIMEOUT            20
  54 /** @endcond */
  55
  56 static bool compare_devices(const void *a, const void *b)
  57 {
  58         const struct jaylink_device *dev;
  59         const struct jaylink_device *new_dev;
  60
  61         dev = a;
  62         new_dev = b;
  63
  64         if (dev->iface != JAYLINK_HIF_TCP)
  65                 return false;
  66
  67         if (memcmp(dev->ipv4_address, new_dev->ipv4_address,
  68                         sizeof(dev->ipv4_address)) != 0)
  69                 return false;
  70
  71         if (dev->serial_number != new_dev->serial_number)
  72                 return false;
  73
  74         if (memcmp(dev->mac_address, new_dev->mac_address,
  75                         sizeof(dev->mac_address)) != 0)
  76                 return false;
  77
  78         if (strcmp(dev->product_name, new_dev->product_name) != 0)
  79                 return false;
  80
  81         if (strcmp(dev->nickname, new_dev->nickname) != 0)
  82                 return false;
  83
  84         if (dev->hw_version.type != new_dev->hw_version.type)
  85                 return false;
  86
  87         if (dev->hw_version.major != new_dev->hw_version.major)
  88                 return false;
  89
  90         if (dev->hw_version.minor != new_dev->hw_version.minor)
  91                 return false;
  92
  93         if (dev->hw_version.revision != new_dev->hw_version.revision)
  94                 return false;
  95
  96         return true;
  97 }
  98
  99 static struct jaylink_device *find_device(const struct jaylink_context *ctx,
 100                 const struct jaylink_device *dev)
 101 {
 102         struct list *item;
 103
 104         item = list_find_custom(ctx->devs, &compare_devices, dev);
 105
 106         if (item)
 107                 return item->data;
 108
 109         return NULL;
 110 }
 111
 112 static bool parse_adv_message(struct jaylink_device *dev,
 113                 const uint8_t *buffer)
 114 {
 115         struct in_addr in;
 116         uint32_t tmp;
 117
 118         if (memcmp(buffer, "Found", 5) != 0)
 119                 return false;
 120
 121         /*
 122          * Use inet_ntoa() instead of inet_ntop() because the latter requires
 123          * at least Windows Vista.
 124          */
 125         memcpy(&in, buffer + 16, 4);
 126         memcpy(dev->ipv4_address, inet_ntoa(in), sizeof(dev->ipv4_address));
 127
 128         memcpy(dev->mac_address, buffer + 32, sizeof(dev->mac_address));
 129         dev->has_mac_address = true;
 130
 131         dev->serial_number = buffer_get_u32(buffer, 48);
 132         dev->valid_serial_number = true;
 133
 134         tmp = buffer_get_u32(buffer, 52);
 135         dev->hw_version.type = (tmp / 1000000) % 100;
 136         dev->hw_version.major = (tmp / 10000) % 100;
 137         dev->hw_version.minor = (tmp / 100) % 100;
 138         dev->hw_version.revision = tmp % 100;
 139         dev->has_hw_version = true;
 140
 141         memcpy(dev->product_name, buffer + 64, sizeof(dev->product_name));
 142         dev->product_name[JAYLINK_PRODUCT_NAME_MAX_LENGTH - 1] = '\0';
 143         dev->has_product_name = isprint((unsigned char)dev->product_name[0]);
 144
 145         memcpy(dev->nickname, buffer + 96, sizeof(dev->nickname));
 146         dev->nickname[JAYLINK_NICKNAME_MAX_LENGTH - 1] = '\0';
 147         dev->has_nickname = isprint((unsigned char)dev->nickname[0]);
 148
 149         return true;
 150 }
 151
 152 static struct jaylink_device *probe_device(struct jaylink_context *ctx,
 153                 struct sockaddr_in *addr, const uint8_t *buffer)
 154 {
 155         struct jaylink_device tmp;
 156         struct jaylink_device *dev;
 157
 158         /*
 159          * Use inet_ntoa() instead of inet_ntop() because the latter requires
 160          * at least Windows Vista.
 161          */
 162         log_dbg(ctx, "Received advertisement message (IPv4 address = %s).",
 163                 inet_ntoa(addr->sin_addr));
 164
 165         if (!parse_adv_message(&tmp, buffer)) {
 166                 log_dbg(ctx, "Received invalid advertisement message.");
 167                 return NULL;
 168         }
 169
 170         log_dbg(ctx, "Found device (IPv4 address = %s).", tmp.ipv4_address);
 171         log_dbg(ctx, "Device: MAC address = %02x:%02x:%02x:%02x:%02x:%02x.",
 172                 tmp.mac_address[0], tmp.mac_address[1], tmp.mac_address[2],
 173                 tmp.mac_address[3], tmp.mac_address[4], tmp.mac_address[5]);
 174         log_dbg(ctx, "Device: Serial number = %u.", tmp.serial_number);
 175
 176         if (tmp.has_product_name)
 177                 log_dbg(ctx, "Device: Product = %s.", tmp.product_name);
 178
 179         if (tmp.has_nickname)
 180                 log_dbg(ctx, "Device: Nickname = %s.", tmp.nickname);
 181
 182         dev = find_device(ctx, &tmp);
 183
 184         if (dev) {
 185                 log_dbg(ctx, "Using existing device instance.");
 186                 return jaylink_ref_device(dev);
 187         }
 188
 189         log_dbg(ctx, "Allocating new device instance.");
 190
 191         dev = device_allocate(ctx);
 192
 193         if (!dev) {
 194                 log_warn(ctx, "Device instance malloc failed.");
 195                 return NULL;
 196         }
 197
 198         dev->iface = JAYLINK_HIF_TCP;
 199
 200         dev->serial_number = tmp.serial_number;
 201         dev->valid_serial_number = tmp.valid_serial_number;
 202
 203         memcpy(dev->ipv4_address, tmp.ipv4_address, sizeof(dev->ipv4_address));
 204
 205         memcpy(dev->mac_address, tmp.mac_address, sizeof(dev->mac_address));
 206         dev->has_mac_address = tmp.has_mac_address;
 207
 208         memcpy(dev->product_name, tmp.product_name, sizeof(dev->product_name));
 209         dev->has_product_name = tmp.has_product_name;
 210
 211         memcpy(dev->nickname, tmp.nickname, sizeof(dev->nickname));
 212         dev->has_nickname = tmp.has_nickname;
 213
 214         dev->hw_version = tmp.hw_version;
 215         dev->has_hw_version = tmp.has_hw_version;
 216
 217         return dev;
 218 }
 219
 220 /** @private */
 221 JAYLINK_PRIV int discovery_tcp_scan(struct jaylink_context *ctx)
 222 {
 223         int ret;
 224         int sock;
 225         int opt_value;
 226         fd_set rfds;
 227         struct sockaddr_in addr;
 228         size_t addr_length;
 229         struct timeval timeout;
 230         uint8_t buf[ADV_MESSAGE_SIZE];
 231         struct jaylink_device *dev;
 232         size_t length;
 233         size_t num_devs;
 234
 235         sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 236
 237         if (sock < 0) {
 238                 log_err(ctx, "Failed to create discovery socket.");
 239                 return JAYLINK_ERR;
 240         }
 241
 242         opt_value = true;
 243
 244         if (!socket_set_option(sock, SOL_SOCKET, SO_BROADCAST, &opt_value,
 245                         sizeof(opt_value))) {
 246                 log_err(ctx, "Failed to enable broadcast option for discovery "
 247                         "socket.");
 248                 socket_close(sock);
 249                 return JAYLINK_ERR;
 250         }
 251
 252         memset(&addr, 0, sizeof(struct sockaddr_in));
 253         addr.sin_family = AF_INET;
 254         addr.sin_port = htons(DISC_PORT);
 255         addr.sin_addr.s_addr = INADDR_ANY;
 256
 257         if (!socket_bind(sock, (struct sockaddr *)&addr,
 258                         sizeof(struct sockaddr_in))) {
 259                 log_err(ctx, "Failed to bind discovery socket.");
 260                 socket_close(sock);
 261                 return JAYLINK_ERR;
 262         }
 263
 264         addr.sin_family = AF_INET;
 265         addr.sin_port = htons(DISC_PORT);
 266         addr.sin_addr.s_addr = INADDR_BROADCAST;
 267
 268         memset(buf, 0, DISC_MESSAGE_SIZE);
 269         memcpy(buf, "Discover", 8);
 270
 271         log_dbg(ctx, "Sending discovery message.");
 272
 273         length = DISC_MESSAGE_SIZE;
 274
 275         if (!socket_sendto(sock, (char *)buf, &length, 0,
 276                         (const struct sockaddr *)&addr, sizeof(addr))) {
 277                 log_err(ctx, "Failed to send discovery message.");
 278                 socket_close(sock);
 279                 return JAYLINK_ERR_IO;
 280         }
 281
 282         if (length < DISC_MESSAGE_SIZE) {
 283                 log_err(ctx, "Only sent %zu bytes of discovery message.",
 284                         length);
 285                 socket_close(sock);
 286                 return JAYLINK_ERR_IO;
 287         }
 288
 289         timeout.tv_sec = DISC_TIMEOUT / 1000;
 290         timeout.tv_usec = (DISC_TIMEOUT % 1000) * 1000;
 291
 292         num_devs = 0;
 293
 294         while (true) {
 295                 FD_ZERO(&rfds);
 296                 FD_SET(sock, &rfds);
 297
 298                 ret = select(sock + 1, &rfds, NULL, NULL, &timeout);
 299
 300                 if (ret <= 0)
 301                         break;
 302
 303                 if (!FD_ISSET(sock, &rfds))
 304                         continue;
 305
 306                 length = ADV_MESSAGE_SIZE;
 307                 addr_length = sizeof(struct sockaddr_in);
 308
 309                 if (!socket_recvfrom(sock, buf, &length, 0,
 310                                 (struct sockaddr *)&addr, &addr_length)) {
 311                         log_warn(ctx, "Failed to receive advertisement "
 312                                 "message.");
 313                         continue;
 314                 }
 315
 316                 /*
 317                  * Filter out messages with an invalid size. This includes the
 318                  * broadcast message we sent before.
 319                  */
 320                 if (length != ADV_MESSAGE_SIZE)
 321                         continue;
 322
 323                 dev = probe_device(ctx, &addr, buf);
 324
 325                 if (dev) {
 326                         ctx->discovered_devs = list_prepend(
 327                                 ctx->discovered_devs, dev);
 328                         num_devs++;
 329                 }
 330         }
 331
 332         socket_close(sock);
 333
 334         if (ret < 0) {
 335                 log_err(ctx, "select() failed.");
 336                 return JAYLINK_ERR;
 337         }
 338
 339         log_dbg(ctx, "Found %zu TCP/IP device(s).", num_devs);
 340
 341         return JAYLINK_OK;
 342 }