From e5cd66313a68634d20e9ac670f4c0a5400295ce9 Mon Sep 17 00:00:00 2001
From: Stephen Birarda <commit@birarda.com>
Date: Thu, 2 May 2013 16:28:19 -0700
Subject: [PATCH] check the number of sscanf matches, store sending socket for
 device to reply

---
 pairing-server/src/main.cpp | 50 +++++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 21 deletions(-)

diff --git a/pairing-server/src/main.cpp b/pairing-server/src/main.cpp
index 0586bb9411..4383efe1ad 100644
--- a/pairing-server/src/main.cpp
+++ b/pairing-server/src/main.cpp
@@ -18,6 +18,7 @@ const int MAX_PACKET_SIZE_BYTES = 1400;
 struct PairableDevice {
     char identifier[64];
     char name[64];
+    sockaddr_in sendingSocket;
     sockaddr_in localSocket;
 };
 
@@ -34,40 +35,47 @@ int indexOfFirstOccurenceOfCharacter(char* haystack, char needle) {
 int main(int argc, const char* argv[]) {
     UDPSocket serverSocket(PAIRING_SERVER_LISTEN_PORT);
     
-    sockaddr deviceAddress;
+    sockaddr_in deviceAddress;
     char deviceData[MAX_PACKET_SIZE_BYTES] = {};
     ssize_t receivedBytes = 0;
     
     std::vector<PairableDevice> devices;
     
     while (true) {
-        if (serverSocket.receive(&deviceAddress, &deviceData, &receivedBytes)) {
+        if (serverSocket.receive((sockaddr *)&deviceAddress, &deviceData, &receivedBytes)) {
             // create a new PairableDevice
             PairableDevice newDevice = {};
             
             int addressBytes[4];
             int socketPort = 0;
             
-            sscanf(deviceData, "A %s %d.%d.%d.%d:%d %s",
-                   newDevice.identifier,
-                   &addressBytes[3],
-                   &addressBytes[2],
-                   &addressBytes[1],
-                   &addressBytes[0],
-                   &socketPort,
-                   newDevice.name);
+            int numMatches = sscanf(deviceData, "A %s %d.%d.%d.%d:%d %s",
+                                    newDevice.identifier,
+                                    &addressBytes[3],
+                                    &addressBytes[2],
+                                    &addressBytes[1],
+                                    &addressBytes[0],
+                                    &socketPort,
+                                    newDevice.name);
             
-            // setup the localSocket for the pairing device
-            newDevice.localSocket.sin_family = AF_INET;
-            newDevice.localSocket.sin_addr.s_addr = (addressBytes[3] |
-                                                     addressBytes[2] << 8 |
-                                                     addressBytes[1] << 16 |
-                                                     addressBytes[0] << 24);
-            newDevice.localSocket.sin_port = socketPort;
-            
-            // push this new device into the vector
-            printf("Adding device %s (%s) to list\n", newDevice.identifier, newDevice.name);
-            devices.push_back(newDevice);
+            if (numMatches >= 6) {
+                // if we have fewer than 6 matches the packet wasn't properly formatted
+                
+                // setup the localSocket for the pairing device
+                newDevice.localSocket.sin_family = AF_INET;
+                newDevice.localSocket.sin_addr.s_addr = (addressBytes[3] |
+                                                         addressBytes[2] << 8 |
+                                                         addressBytes[1] << 16 |
+                                                         addressBytes[0] << 24);
+                newDevice.localSocket.sin_port = socketPort;
+                
+                // store this device's sending socket so we can talk back to it
+                newDevice.sendingSocket = deviceAddress;
+                
+                // push this new device into the vector
+                printf("Adding device %s (%s) to list\n", newDevice.identifier, newDevice.name);
+                devices.push_back(newDevice);
+            }
         }
     }