From e4c0d74883205d54a8fbe83c086267123de70db7 Mon Sep 17 00:00:00 2001
From: Matias Fontanini <matias.fontanini@gmail.com>
Date: Thu, 7 Jun 2012 11:45:51 -0300
Subject: [PATCH] Added Utils::route_entries to retrieve routing table entries.

---
 include/utils.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++---
 src/utils.cpp   | 52 +++++++++++++++----------------------------------
 2 files changed, 65 insertions(+), 39 deletions(-)

diff --git a/include/utils.h b/include/utils.h
index d1425ad..b51cb76 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -29,6 +29,7 @@
 #endif
 #include <string>
 #include <set>
+#include <fstream>
 #include <stdint.h>
 #include "packetsender.h"
 #include "ipaddress.h"
@@ -49,6 +50,14 @@ namespace Tins {
             uint8_t hw_addr[6];
         };
         
+        /**
+         * \brief Struct that represents an entry in /proc/net/route
+         */
+        struct RouteEntry {
+            std::string interface;
+            IPv4Address destination, gateway, mask;
+        };
+        
         /** \brief Convert a dotted-ip-notation string to an integer.
          *
          * \param ip A dotted ip notation string
@@ -193,7 +202,16 @@ namespace Tins {
          * 
          * \return bool indicating wether the lookup was successfull.
          */
-        bool gateway_from_ip(IPv4Address ip, IPv4Address &gw_addr) ;
+        bool gateway_from_ip(IPv4Address ip, IPv4Address &gw_addr);
+        
+        
+        /**
+         * \brief Retrieves entries int the routing table.
+         * 
+         * \brief output ForwardIterator in which entries will be stored.
+         */
+        template<class ForwardIterator>
+        void route_entries(ForwardIterator output);
         
 
         /** \brief Convert 16 bit integer into network byte order.
@@ -275,7 +293,35 @@ namespace Tins {
             if(ifaddrs)
                 freeifaddrs(ifaddrs);
         }
-    };
-};
+        
+        namespace Internals {
+            void skip_line(std::istream &input);
+            bool from_hex(const std::string &str, uint32_t &result);
+        }
+    }
+}
+
+template<class ForwardIterator>
+void Tins::Utils::route_entries(ForwardIterator output) {
+    using namespace Utils::Internals;
+    std::ifstream input("/proc/net/route");
+    std::string destination, mask, gw;
+    uint32_t dummy;
+    skip_line(input);
+    RouteEntry entry;
+    while(input >> entry.interface >> destination >> gw) {
+        for(unsigned i(0); i < 5; ++i)
+            input >> mask;
+        from_hex(destination, dummy);
+        entry.destination = net_to_host_l(dummy);
+        from_hex(mask, dummy);
+        entry.mask = net_to_host_l(dummy);
+        from_hex(gw, dummy);
+        entry.gateway = net_to_host_l(dummy);
+        skip_line(input);
+        *output = entry;
+        ++output;
+    }
+}
 
 #endif
diff --git a/src/utils.cpp b/src/utils.cpp
index 140ee6c..e22bc4d 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -21,7 +21,6 @@
 
 #include <stdexcept>
 #include <sstream>
-#include <fstream>
 #include <stdexcept>
 #include <cassert>
 #include <cstring>
@@ -105,7 +104,7 @@ struct InterfaceInfoCollector {
     }
 };
 
-bool from_hex(const string &str, uint32_t &result) {
+bool Tins::Utils::Internals::from_hex(const string &str, uint32_t &result) {
     unsigned i(0);
     result = 0;
     while(i < str.size()) {
@@ -122,7 +121,7 @@ bool from_hex(const string &str, uint32_t &result) {
     return true;
 }
 
-void skip_line(istream &input) {
+void Tins::Utils::Internals::skip_line(istream &input) {
     int c = 0;
     while(c != '\n' && input)
          c = input.get();
@@ -248,46 +247,27 @@ bool Tins::Utils::resolve_hwaddr(const string &iface, IPv4Address ip,
 string Tins::Utils::interface_from_ip(IPv4Address ip) {
     if(ip == 0x7f000001)
         return "lo";
-    ifstream input("/proc/net/route");
-    bool match(false);
-    string iface;
-    string destination, mask;
-    uint32_t destination_int, mask_int, ip_int = ip;
-    skip_line(input);
-    while(!match) {
-        input >> iface >> destination;
-        for(unsigned i(0); i < 6; ++i)
-            input >> mask;
-        from_hex(destination, destination_int);
-        from_hex(mask, mask_int);
-        if((ip_int & mask_int) == destination_int)
-            return iface;
-        skip_line(input);
+    std::vector<RouteEntry> entries;
+    uint32_t ip_int = ip;
+    route_entries(std::back_inserter(entries));
+    for(std::vector<RouteEntry>::const_iterator it(entries.begin()); it != entries.end(); ++it) {
+        std::cout << std::hex << ip_int << " " << (uint32_t)it->mask << " " << (uint32_t)it->destination << "\n";
+        if((ip_int & it->mask) == it->destination)
+            return it->interface;
     }
     return "";
 }
 
 bool Tins::Utils::gateway_from_ip(IPv4Address ip, IPv4Address &gw_addr) {
-    ifstream input("/proc/net/route");
-    bool match(false);
-    string iface;
-    string destination, mask, gw;
-    uint32_t destination_int, mask_int;
-    ip = Utils::net_to_host_l(ip);
-    skip_line(input);
-    while(!match) {
-        input >> iface >> destination >> gw;
-        for(unsigned i(0); i < 5; ++i)
-            input >> mask;
-        from_hex(destination, destination_int);
-        from_hex(mask, mask_int);
-        if((ip & mask_int) == destination_int) {
-            uint32_t tmp_ip;
-            from_hex(gw, tmp_ip);
-            gw_addr = net_to_host_l(tmp_ip);
+    std::vector<RouteEntry> entries;
+    uint32_t ip_int = ip;
+    route_entries(std::back_inserter(entries));
+    for(std::vector<RouteEntry>::const_iterator it(entries.begin()); it != entries.end(); ++it) {
+        std::cout << std::hex << ip_int << " " << (uint32_t)it->mask << " " << (uint32_t)it->destination << "\n";
+        if((ip_int & it->mask) == it->destination) {
+            gw_addr = it->gateway;
             return true;
         }
-        skip_line(input);
     }
     return false;
 }