[GitHub] [guacamole-server] mike-jumper commented on a change in pull request #267: GUACAMOLE-513: Implement Wake-on-LAN support in libguac

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mike-jumper commented on a change in pull request #267: GUACAMOLE-513: Implement Wake-on-LAN support in libguac
URL: https://github.com/apache/guacamole-server/pull/267#discussion_r394537195
 
 

 ##########
 File path: src/libguac/wol.c
 ##########
 @@ -0,0 +1,128 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+
+#include "guacamole/wol.h"
+
+/**
+ * Generate the magic Wake-on-LAN (WoL) packet for the specified MAC address
+ * and place it in the character array.
+ * 
+ * @param packet
+ *     The character array that will contain the generated packet.
+ * 
+ * @param mac_address
+ *     The unsigned int representation of the MAC address to place in the packet.
+ */
+static void __guac_wol_create_magic_packet(unsigned char packet[],
+        unsigned int mac_address[]) {
+    
+    int i;
+    unsigned char mac[6];
+    
+    /* Concurrently fill the first part of the packet with 0xFF, and copy the
+     MAC address from the int array to the char array. */
+    for (i = 0; i < 6; i++) {
+        packet[i] = 0xFF;
+        mac[i] = mac_address[i];
+    }
+    
+    /* Copy the MAC address contents into the char array that is storing
+     the rest of the packet. */
+    for (i = 1; i <= 16; i++) {
+        memcpy(&packet[i * 6], &mac, 6 * sizeof(unsigned char));
+    }
+    
+}
+
+/**
+ * Send the magic Wake-on-LAN (WoL) packet to the specified broadcast address,
+ * returning the number of bytes sent, or zero if any error occurred and nothing
+ * was sent.
+ * 
+ * @param broadcast_addr
+ *     The broadcast address to which to send the magic WoL packet.
+ * 
+ * @param packet
+ *     The magic WoL packet to send.
+ * 
+ * @return 
+ *     The number of bytes sent, or zero if nothing could be sent.
+ */
+static ssize_t __guac_wol_send_packet(const char* broadcast_addr,
+        unsigned char packet[]) {
+    
+    int wol_bcast = 1;
+    struct sockaddr_in wol_dest;
+    int wol_socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    
+    /* Attempt to set broadcast; exit with error if this fails. */
+    if (setsockopt(wol_socket, SOL_SOCKET, SO_BROADCAST, &wol_bcast, sizeof(wol_bcast)) < 0) {
+        return 0;
+    }
+    
+    /* Set server endpoint to the broadcast address. */
+    wol_dest.sin_family = AF_INET;
+    wol_dest.sin_port = htons(9);
+    wol_dest.sin_addr.s_addr = inet_addr(broadcast_addr);
+    
+    /* Send the packet and return number of bytes sent. */
+    return sendto(wol_socket, &packet, sizeof(unsigned char) * 102, 0,
+            (struct sockaddr*) &wol_dest, sizeof(wol_dest));
+ 
+}
+
+int guac_wol_wake(const char* mac_addr, const char* broadcast_addr,
+        const int wait_time) {
+    
+    unsigned char wol_packet[102];
 
 Review comment:
   What's this 102 magic number?

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