ifconfig: Stop supporting setting/displaying default gateway

The `route` command allows more sophiscated control over routing tables
now, and supporting this in ifconfig is no longer meaningful.

Base/usr/share/man/man1/ifconfig.md

@@ -5,7 +5,7 @@ ifconfig
 ## Synopsis
 
 ```sh
-$ ifconfig [--ipv4 ip] [--adapter adapter] [--gateway gateway] [--mask mask]
+$ ifconfig [--ipv4 ip] [--adapter adapter] [--mask mask]
 ```
 
 ## Description
@@ -16,7 +16,6 @@ Display or modify the configuration of each network interface.
 
 * `-i ip`, `--ipv4 ip`: Set the IP address of the selected network
 * `-a adapter`, `--adapter adapter`: Select a specific network adapter to configure
-* `-g gateway`, `--gateway gateway`: Set the default gateway of the selected network
 * `-m mask`, `--mask mask`: Set the network mask of the selected network
 
 <!-- Auto-generated through ArgsParser -->

Userland/Utilities/ifconfig.cpp

@@ -27,18 +27,16 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 {
     char const* value_ipv4 = nullptr;
     char const* value_adapter = nullptr;
-    char const* value_gateway = nullptr;
     char const* value_mask = nullptr;
 
     Core::ArgsParser args_parser;
     args_parser.set_general_help("Display or modify the configuration of each network interface.");
     args_parser.add_option(value_ipv4, "Set the IP address of the selected network", "ipv4", 'i', "ip");
     args_parser.add_option(value_adapter, "Select a specific network adapter to configure", "adapter", 'a', "adapter");
-    args_parser.add_option(value_gateway, "Set the default gateway of the selected network", "gateway", 'g', "gateway");
     args_parser.add_option(value_mask, "Set the network mask of the selected network", "mask", 'm', "mask");
     args_parser.parse(arguments);
 
-    if (!value_ipv4 && !value_adapter && !value_gateway && !value_mask) {
+    if (!value_ipv4 && !value_adapter && !value_mask) {
         auto file = TRY(Core::File::open("/proc/net/adapters", Core::OpenMode::ReadOnly));
         auto json = TRY(JsonValue::from_string(file->read_all()));
 
@@ -49,7 +47,6 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
             auto class_name = if_object.get("class_name").to_string();
             auto mac_address = if_object.get("mac_address").to_string();
             auto ipv4_address = if_object.get("ipv4_address").to_string();
-            auto gateway = if_object.get("ipv4_gateway").to_string();
             auto netmask = if_object.get("ipv4_netmask").to_string();
             auto packets_in = if_object.get("packets_in").to_u32();
             auto bytes_in = if_object.get("bytes_in").to_u32();
@@ -61,7 +58,6 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
             outln("\tmac: {}", mac_address);
             outln("\tipv4: {}", ipv4_address);
             outln("\tnetmask: {}", netmask);
-            outln("\tgateway: {}", gateway);
             outln("\tclass: {}", class_name);
             outln("\tRX: {} packets {} bytes ({})", packets_in, bytes_in, human_readable_size(bytes_in));
             outln("\tTX: {} packets {} bytes ({})", packets_out, bytes_out, human_readable_size(bytes_out));
@@ -140,30 +136,6 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
                 return 1;
             }
         }
-
-        if (value_gateway) {
-            auto address = IPv4Address::from_string(value_gateway);
-
-            int fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
-            if (fd < 0) {
-                perror("socket");
-                return 1;
-            }
-
-            struct rtentry rt;
-            memset(&rt, 0, sizeof(rt));
-
-            rt.rt_dev = const_cast<char*>(ifname.characters());
-            rt.rt_gateway.sa_family = AF_INET;
-            ((sockaddr_in&)rt.rt_gateway).sin_addr.s_addr = address.value().to_in_addr_t();
-            rt.rt_flags = RTF_UP | RTF_GATEWAY;
-
-            int rc = ioctl(fd, SIOCADDRT, &rt);
-            if (rc < 0) {
-                perror("ioctl(SIOCADDRT)");
-                return 1;
-            }
-        }
     }
     return 0;
 }