From fa9c260d851477ede3e37d85271f315a06444dc1 Mon Sep 17 00:00:00 2001
From: Matias Fontanini <matias.fontanini@gmail.com>
Date: Tue, 20 Mar 2012 12:07:08 -0300
Subject: [PATCH] Added Utils::ping_address. Fixed bugs in
 PacketSender::recv_match_loop.

---
 include/packetsender.h |  2 ++
 include/utils.h        | 17 +++++++++++++++++
 src/packetsender.cpp   | 37 ++++++++++++++++++++++++++++++-------
 src/utils.cpp          | 14 +++++++++++++-
 4 files changed, 62 insertions(+), 8 deletions(-)

diff --git a/include/packetsender.h b/include/packetsender.h
index 2ea0678..72cf9da 100644
--- a/include/packetsender.h
+++ b/include/packetsender.h
@@ -29,6 +29,7 @@
 
 #ifndef WIN32
     #include <netinet/in.h>
+    #include <sys/time.h>
 #endif
 
 #include "pdu.h"
@@ -169,6 +170,7 @@ namespace Tins {
         typedef std::map<SocketType, int> SocketTypeMap;
 
         int find_type(SocketType type);
+        int timeval_subtract (struct timeval *result, struct timeval *x, struct timeval *y);
         
         PDU *recv_match_loop(int sock, PDU *pdu, struct sockaddr* link_addr, socklen_t addrlen);
 
diff --git a/include/utils.h b/include/utils.h
index 7409fff..552042d 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -78,6 +78,23 @@ namespace Tins {
          * \param to_resolve The domain name/ip address to resolve.
          */
         uint32_t resolve_ip(const std::string &to_resolve) throw (std::runtime_error);
+        
+        /**
+         * \brief Pings an ip address.
+         * 
+         * This function pings an IP address and returns the ICMP response.
+         * If no response is received, 0 is returned
+         * 
+         * \param ip The IP address to ping.
+         * \param sender The PacketSender that will send the ping request.
+         * \param ip_src The source IP address that will be used in the packet.
+         * If 0, or no parameter is provided, then that IP address is looked
+         * up using Utils::interface_ip.
+         * 
+         * \return PDU * containing either 0 if no response was received,
+         * or the ICMP response otherwise.
+         */
+        PDU *ping_address(uint32_t ip, PacketSender *sender, uint32_t ip_src = 0);
 
         /** \brief Resolves the hardware address for a given ip.
          *
diff --git a/src/packetsender.cpp b/src/packetsender.cpp
index 5f4afa9..1f0c2d6 100644
--- a/src/packetsender.cpp
+++ b/src/packetsender.cpp
@@ -22,16 +22,15 @@
 #ifndef WIN32
     #include <sys/socket.h>
     #include <sys/select.h>
-    #include <sys/time.h>
     #include <arpa/inet.h>
     #include <unistd.h>
     #include <linux/if_ether.h>
     #include <linux/if_packet.h>
     #include <netdb.h>
 #endif
-#include <assert.h>
+#include <cassert>
 #include <errno.h>
-#include <string.h>
+#include <cstring>
 #include <ctime>
 #include "packetsender.h"
 
@@ -156,16 +155,40 @@ Tins::PDU *Tins::PacketSender::recv_match_loop(int sock, PDU *pdu, struct sockad
             if(pdu->matches_response(buffer, size))
                 return pdu->clone_packet(buffer, size);
         }
-        struct timeval this_time;
+        struct timeval this_time, diff;
         gettimeofday(&this_time, 0);
-        if(end_time.tv_sec <= this_time.tv_sec && end_time.tv_usec <= this_time.tv_usec)
+        if(timeval_subtract(&diff, &this_time, &end_time)) {
             return 0;
-        timeout.tv_sec = end_time.tv_sec - this_time.tv_sec;
-        timeout.tv_usec = end_time.tv_usec;
+        }
+        timeout.tv_sec = diff.tv_sec;
+        timeout.tv_usec = diff.tv_usec;
     }
     return 0;
 }
 
+int Tins::PacketSender::timeval_subtract (struct timeval *result, struct timeval *x, struct timeval *y) {
+    /* Perform the carry for the later subtraction by updating y. */
+    if (x->tv_usec < y->tv_usec) {
+        int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
+        y->tv_usec -= 1000000 * nsec;
+        y->tv_sec += nsec;
+    }
+    
+    if (x->tv_usec - y->tv_usec > 1000000) {
+        int nsec = (x->tv_usec - y->tv_usec) / 1000000;
+        y->tv_usec += 1000000 * nsec;
+        y->tv_sec -= nsec;
+    }
+
+    /* Compute the time remaining to wait.
+    tv_usec is certainly positive. */
+    result->tv_sec = x->tv_sec - y->tv_sec;
+    result->tv_usec = x->tv_usec - y->tv_usec;
+
+    /* Return 1 if result is negative. */
+    return x->tv_sec < y->tv_sec;
+}
+
 int Tins::PacketSender::find_type(SocketType type) {
     SocketTypeMap::iterator it = _types.find(type);
     if(it == _types.end())
diff --git a/src/utils.cpp b/src/utils.cpp
index fb56855..f52623c 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -23,7 +23,6 @@
 #include <sstream>
 #include <fstream>
 #include <stdexcept>
-#include <iostream> //borrame
 #include <cassert>
 #include <cstring>
 #ifndef WIN32
@@ -33,6 +32,8 @@
 #endif
 #include "utils.h"
 #include "pdu.h"
+#include "ip.h"
+#include "icmp.h"
 #include "arp.h"
 
 
@@ -187,6 +188,17 @@ uint32_t Tins::Utils::resolve_ip(const string &to_resolve) throw (std::runtime_e
     return Utils::net_to_host_l(((struct in_addr**)data->h_addr_list)[0]->s_addr);
 }
 
+Tins::PDU *Tins::Utils::ping_address(uint32_t ip, PacketSender *sender, uint32_t ip_src) {
+    ICMP *icmp = new ICMP(ICMP::ECHO_REQUEST);
+    if(!ip_src) {
+        std::string iface(Utils::interface_from_ip(ip));
+        if(!iface.size() || !Utils::interface_ip(iface, ip_src))
+            return 0;
+    }
+    IP ip_packet(ip, ip_src, icmp);
+    return sender->send_recv(&ip_packet);
+}
+
 bool Tins::Utils::resolve_hwaddr(const string &iface, uint32_t ip, uint8_t *buffer, PacketSender *sender) {
     uint32_t my_ip;
     uint8_t my_hw[6];