Properly determine device name from target if possible

nping/EchoServer.cc

@@ -1411,14 +1411,17 @@ int EchoServer::start() {
     nping_fatal(QT_3, "Failed to create new nsock_iod.  QUITTING.\n");
 
   /* Open pcap */
-  nping_print(DBG_2,"Opening pcap device %s", o.getDevice());
-  Strncpy(pcapdev, o.getDevice(), sizeof(pcapdev));
+  const char *device = o.getDevice();
+  if (!device)
+    nping_fatal(QT_3, "Unable to determine device name.  QUITTING.\n");
+  nping_print(DBG_2,"Opening pcap device %s", device);
+  Strncpy(pcapdev, device, sizeof(pcapdev));
   rc = nsock_pcap_open(nsp, pcap_nsi, pcapdev, MAX_ECHOED_PACKET_LEN, 1,
                        ProbeMode::getBPFFilterString());
   if (rc)
-    nping_fatal(QT_3, "Error opening capture device %s\n", o.getDevice());
+    nping_fatal(QT_3, "Error opening capture device %s\n", device);
   else
-    nping_print(VB_0,"Packet capture will be performed using network interface %s.", o.getDevice());
+    nping_print(VB_0,"Packet capture will be performed using network interface %s.", device);
   nping_print(VB_0,"Waiting for connections...");
 
   /* Get a socket suitable for an accept() call */

nping/NpingOps.cc

@@ -701,8 +701,14 @@ int NpingOps::setDevice(char *n){
 } /* End of setDevice() */
 
 
-char *NpingOps::getDevice(){
-  return this->device;
+const char *NpingOps::getDevice(){
+  if (this->device_set)
+    return this->device;
+  if (this->targets.devices.empty())
+    return NULL;
+  if (this->targets.devices.size() > 1)
+    nping_fatal(QT_3, "Nping does not support targets on multiple devices. QUITTING.\n");
+  return this->targets.devices.front()->getName();
 } /* End of getDevice() */
 
 
@@ -2301,86 +2307,8 @@ if (this->isRoot() && this->havePcap()==false){
         nping_print(VB_0, "Warning: Payload supplied in TCP Connect mode. Payload will be ignored.");
   }
 
-/** SOURCE IP, SOURCE MAC and NETWORK DEVICE *********************************/
-/* If we are in a mode where we need to craft IP packets, then we need to
- * obtain a network interface name and a source IP address. There are three
- * different possibilities:
- *  1. User did NOT specify both network interface and source IP address.
- *  2. User did specify a network interface but not a source IP address.
- *  3. User did actually supply a source IP but not a network interface name
- *
- * I know the following code is ugly but the thing is that we want to determine
- * interface and source IP without user intervention, so we try in many ways
- * until either we succeed or we run out of possibilities and fatal().
- */
-if( this->getMode()!=TCP_CONNECT && this->getMode()!=UDP_UNPRIV && this->getRole()!=ROLE_SERVER){
-
-    char devbuff[32];
-    char *dev;
-    struct sockaddr_storage ss, ifaddr;
-    struct sockaddr_in *s4=(struct sockaddr_in *)&ifaddr;
-    struct sockaddr_in6 *s6=(struct sockaddr_in6 *)&ifaddr;
-    size_t ss_len;
-    char hostname[128];
-    memset(&ss, 0, sizeof(struct sockaddr_storage));
-    memset(&ifaddr, 0, sizeof(struct sockaddr_storage));
-
-
-   /* CASE 1: User did not specify a device so we have to select one. */
-    if( !this->issetDevice() ){
-        if( this->ipv4() ){
-            /* Ugly hack. Get the first resolvable target and determine net interface. Let's
-             * hope user did not specify something that mixes localhost with
-             * other targets, like "nping localhost google.com playboy.com" */
-             for(int z=0; z<this->targets.getTargetSpecCount(); z++){
-                if( this->targets.getNextTargetAddressAndName(&ss, &ss_len, hostname, sizeof(hostname)) == OP_SUCCESS )
-                    break;
-                else if( z>=(this->targets.getTargetSpecCount()-1) )
-                    nping_fatal(QT_3,"Cannot find a valid target. Please make sure the specified hosts are either IP addresses in standard notation or hostnames that can be resolved with DNS");
-             }
-             this->targets.rewind();
-
-             /* Try to obtain a device name from the target IP */
-             if ( getNetworkInterfaceName( &ss , devbuff) != OP_SUCCESS ) {
-                /* If that didn't work, ask libpcap */
-                if ( (dev = this->select_network_iface()) == NULL)
-                    nping_fatal(QT_3, "Cannot obtain device for packet capture");
-                else {
-                    this->setDevice( dev );
-                    free(dev);
-                }
-                /* Libpcap gave us a device name, try to obtain it's IP */
-                if ( devname2ipaddr(this->getDevice(), this->af(), &ifaddr) != 0 ){
-                    if( this->isRoot() )
-                        nping_fatal(QT_3,"Cannot figure out what source address to use for device %s, does it even exist?", this->getDevice());
-                    else
-                        nping_fatal(QT_3,"Cannot figure out what source address to use for device %s, are you root?", this->getDevice());
-                }
-                else{
-                    if( s4->sin_family==AF_INET )
-                        this->setIPv4SourceAddress(s4->sin_addr);
-                    else if ( s6->sin6_family==AF_INET6 )
-                        this->setIPv6SourceAddress(s6->sin6_addr.s6_addr);
-                }
-            }else{
-                this->setDevice(devbuff);
-            }
-        }else{ /* In IPv6 we just select one in libpcap and hope is the right one */
-            char *selected_iface=this->select_network_iface();
-            if(selected_iface==NULL)
-                nping_fatal(QT_3, "Error trying to find a suitable network interface ");
-            else {
-                this->setDevice( selected_iface );
-                free(selected_iface);
-            }
-        }
-    } /* CASE 2: User did actually supply a device name */
-    else{
-        nping_print(DBG_2, "Using network interface \"%s\"", this->getDevice() );
-    }
-
 /* The echo server needs to find out a network interface*/
-}else if (this->getRole()==ROLE_SERVER && this->issetDevice()==false){
+if (this->getRole()==ROLE_SERVER && this->issetDevice()==false){
   char *selected_iface=this->select_network_iface();
   if(selected_iface==NULL)
     nping_fatal(QT_3, "Error trying to find a suitable network interface ");

nping/NpingOps.h

@@ -344,7 +344,7 @@ class NpingOps {
     bool sendEth();
 
     int setDevice(char *n);
-    char *getDevice();
+    const char *getDevice();
     bool issetDevice();
 
     int setSpoofSource();

nping/NpingTargets.cc

@@ -67,16 +67,33 @@
 #include "NpingTargets.h"
 #include "common_modified.h"
 #include <algorithm>
+#include <cstring>
 
 extern NpingOps o;
 
+bool NpingDevice::strEqual(const char *name) const
+{
+  return 0 == std::strcmp(devname, name);
+}
+
 NpingTargets::NpingTargets()
 : ready(false), current_target(0)
 {
+  if (o.issetDevice()) {
+    devices.push_back(new NpingDevice(o.getDevice()));
+  }
 } /* End of NpingTargets constructor */
 
 
 NpingTargets::~NpingTargets(){
+  while (!netblocks.empty()) {
+    delete netblocks.back();
+    netblocks.pop_back();
+  }
+  while (!devices.empty()) {
+    delete devices.back();
+    devices.pop_back();
+  }
 } /* End of NpingTargets destructor */
 
 
@@ -91,8 +108,20 @@ int NpingTargets::addSpec(char *spec){
     return OP_FAILURE;
   netblocks.push_back(nb);
   return OP_SUCCESS;
-} /* End of NpingTargets */
+} /* End of NpingTargets::addSpec */
 
+void NpingTargets::addDevice(const char *dev)
+{
+  if(dev == NULL || *dev == '\0')
+    return;
+  for (std::vector<NpingDevice *>::iterator it=devices.begin();
+      it != devices.end(); ++it) {
+    NpingDevice *d = *it;
+    if (d->strEqual(dev))
+      return;
+  }
+  devices.push_back(new NpingDevice(dev));
+}
 
 /** Returns next target */
 int NpingTargets::getNextTargetAddressAndName(struct sockaddr_storage *t, size_t *tlen, char *hname, size_t hlen){
@@ -309,6 +338,7 @@ int NpingTargets::processSpecs(){
 
     /* Insert current target into targets array */
     this->Targets.push_back(mytarget);
+    this->addDevice(mytarget->getDeviceName());
   }
 
   /* getNextTarget() checks this to ensure user has previously called processSpecs() */

nping/NpingTargets.h

@@ -72,6 +72,17 @@
 
 #define MAX_NPING_HOSTNAME_LEN 512    /**< Max length for named hosts */
 
+class NpingDevice {
+private:
+  // Note: this class doesn't own the storage for this name;
+  // it has to continue to exist elsewhere.
+  const char *devname;
+public:
+  NpingDevice(const char *d) : devname(d) {}
+  bool strEqual(const char *name) const;
+  const char *getName() const { return devname; }
+};
+
 class NpingTargets {
 
   private:
@@ -87,6 +98,7 @@ class NpingTargets {
     NpingTargets();
     ~NpingTargets();
     int addSpec(char *spec);
+    void addDevice(const char *dev);
     int getNextTargetSockAddr(struct sockaddr_storage *t, size_t *tlen);
     NpingTarget *getNextTarget();
     int rewind();
@@ -102,6 +114,7 @@ class NpingTargets {
     /* TODO: Make private */
     NpingTarget *currenths;
     std::vector<NpingTarget *> Targets;
+    std::vector<NpingDevice *> devices;
 
 }; /* End of class NpingTargets */
 

nping/ProbeMode.cc

@@ -98,7 +98,7 @@ int ProbeMode::init_nsock(){
       if ((nsp = nsock_pool_new(NULL)) == NULL)
         nping_fatal(QT_3, "Failed to create new pool.  QUITTING.\n");
       const char *device = o.getDevice();
-      if (*device)
+      if (device && *device)
         nsock_pool_set_device(nsp, device);
 
       /* Allow broadcast addresses */
@@ -304,7 +304,7 @@ int ProbeMode::start(){
 
     if( o.getMode()!=ARP && o.sendEth()==false ){
         /* Get socket descriptor. No need for it in ARP since we send at eth level */
-        if ((rawipsd = netutil_raw_socket(o.issetDevice() ? o.getDevice() : NULL)) < 0 )
+        if ((rawipsd = netutil_raw_socket(o.getDevice())) < 0 )
             nping_fatal(QT_3,"Couldn't acquire raw socket. Are you root?");
     }
 
@@ -314,30 +314,33 @@ int ProbeMode::start(){
 
     /* Set up libpcap */
     if(!o.disablePacketCapture()){
+        const char *device = o.getDevice();
+        if (!device)
+            nping_fatal(QT_3, "Unable to determine device name.  QUITTING.\n");
         /* Create new IOD for pcap */
         if ((pcap_nsi = nsock_iod_new(nsp, NULL)) == NULL)
             nping_fatal(QT_3, "Failed to create new nsock_iod.  QUITTING.\n");
 
         /* Open pcap */
         filterstring=getBPFFilterString();
-        nping_print(DBG_2,"Opening pcap device %s", o.getDevice() );
+        nping_print(DBG_2,"Opening pcap device %s", device);
         #ifdef WIN32
         /* Nping normally uses device names obtained through dnet for interfaces,
          * but Pcap has its own naming system.  So the conversion is done here */
-          if (!DnetName2PcapName(o.getDevice(), pcapdev, sizeof(pcapdev))) {
+          if (!DnetName2PcapName(device, pcapdev, sizeof(pcapdev))) {
                /* Oh crap -- couldn't find the corresponding dev apparently.
                 * Let's just go with what we have then ... */
-               Strncpy(pcapdev, o.getDevice(), sizeof(pcapdev));
+               Strncpy(pcapdev, device, sizeof(pcapdev));
           }
         #else
-          Strncpy(pcapdev, o.getDevice(), sizeof(pcapdev));
+          Strncpy(pcapdev, device, sizeof(pcapdev));
         #endif
 
         rc = nsock_pcap_open(nsp, pcap_nsi, pcapdev, 8192,
                              (o.spoofSource()) ? 1 : 0, filterstring);
         if (rc)
-            nping_fatal(QT_3, "Error opening capture device %s\n", o.getDevice());
-        nping_print(DBG_2,"Pcap device %s open successfully", o.getDevice());
+            nping_fatal(QT_3, "Error opening capture device %s\n", device);
+        nping_print(DBG_2,"Pcap device %s open successfully", device);
     }
 
     /* Ready? Go! */