Chapter 10 iflist example add

Author: Artiom N.

src/book01/ch10/cpp/CMakeLists.txt

@@ -1,6 +1,7 @@
 cmake_minimum_required(VERSION 3.10)
 
 if (UNIX)
+    add_subdirectory("if_list")
     add_subdirectory("if_nameindex")
     add_subdirectory("if_rename")
     add_subdirectory("ethtool")

src/book01/ch10/cpp/if_list/CMakeLists.txt

@@ -0,0 +1,6 @@
+cmake_minimum_required(VERSION 3.10)
+
+project("${CHAPTER_NAME}if_list" C CXX)
+
+add_executable("${PROJECT_NAME}" main.cpp)
+target_link_libraries("${PROJECT_NAME}" socket-wrapper)

src/book01/ch10/cpp/if_list/main.cpp

@@ -0,0 +1,68 @@
+extern "C"
+{
+#include <net/if.h>
+#include <sys/ioctl.h>
+}
+
+#include <socket_wrapper/socket_class.h>
+#include <socket_wrapper/socket_headers.h>
+#include <socket_wrapper/socket_wrapper.h>
+
+#include <array>
+#include <cassert>
+#include <iostream>
+#include <stdexcept>
+#include <vector>
+
+
+int main()
+{
+    ifconf ifc = {0};
+
+    const socket_wrapper::SocketWrapper sock_wrap;
+
+    const auto sock = socket_wrapper::Socket(AF_INET, SOCK_DGRAM, 0);
+
+    if (sock < 0)
+    {
+        throw std::system_error(errno, std::system_category(), "socket");
+    }
+
+    if (ioctl(sock, SIOCGIFCONF, &ifc) < 0)
+    {
+        throw std::system_error(errno, std::system_category(), "SIOCGIFCONF with 0 buffer");
+    }
+
+    std::cout << "Buffer size = " << ifc.ifc_len << std::endl;
+    assert(ifc.ifc_len);
+
+    std::vector<char> buffer(ifc.ifc_len);
+
+    ifc.ifc_buf = buffer.data();
+
+    if (ioctl(sock, SIOCGIFCONF, &ifc) < 0)
+    {
+        throw std::system_error(errno, std::system_category(), "SIOCGIFCONF");
+    }
+
+    for (auto i = ifc.ifc_req; i != ifc.ifc_req + ifc.ifc_len / sizeof(ifreq); ++i)
+    {
+        std::cout << i->ifr_name << ": ";
+        if (AF_INET == i->ifr_addr.sa_family)
+        {
+            std::array<char, INET_ADDRSTRLEN> buf;
+            std::cout << inet_ntop(
+                AF_INET, &(reinterpret_cast<sockaddr_in*>(&i->ifr_addr)->sin_addr), buf.data(), buf.size());
+        }
+        else if (AF_INET6 == i->ifr_addr.sa_family)
+        {
+            std::array<char, INET6_ADDRSTRLEN> buf;
+            std::cout << inet_ntop(
+                AF_INET6, &(reinterpret_cast<sockaddr_in6*>(&i->ifr_addr)->sin6_addr), buf.data(), buf.size());
+        }
+
+        std::cout << std::endl;
+    }
+
+    return EXIT_SUCCESS;
+}