From 8313d357499b3ac473120252143037e6e633bf60 Mon Sep 17 00:00:00 2001
From: brapru <brapru@pm.me>
Date: Sat, 24 Jul 2021 20:04:11 -0400
Subject: [PATCH] Kernel: Support ioctl SIOCSARP and SIOCDARP

Creates ioctl calls necessary to set/delete an entry from the ARP table
---
 Kernel/Net/IPv4Socket.cpp                   | 30 +++++++++++++++++++++
 Kernel/UnixTypes.h                          |  8 ++++++
 Userland/Libraries/LibC/net/route.h         |  8 ++++++
 Userland/Libraries/LibC/sys/ioctl_numbers.h |  4 +++
 4 files changed, 50 insertions(+)

diff --git a/Kernel/Net/IPv4Socket.cpp b/Kernel/Net/IPv4Socket.cpp
index 011efabdea..aded09dc5a 100644
--- a/Kernel/Net/IPv4Socket.cpp
+++ b/Kernel/Net/IPv4Socket.cpp
@@ -604,6 +604,32 @@ int IPv4Socket::ioctl(FileDescription&, unsigned request, FlatPtr arg)
         return -EINVAL;
     };
 
+    auto ioctl_arp = [request, arg]() {
+        arpreq arp_req;
+        if (!copy_from_user(&arp_req, (arpreq*)arg))
+            return -EFAULT;
+
+        switch (request) {
+        case SIOCSARP:
+            if (!Process::current()->is_superuser())
+                return -EPERM;
+            if (arp_req.arp_pa.sa_family != AF_INET)
+                return -EAFNOSUPPORT;
+            update_arp_table(IPv4Address(((sockaddr_in&)arp_req.arp_pa).sin_addr.s_addr), *(MACAddress*)&arp_req.arp_ha.sa_data[0], UpdateArp::Set);
+            return 0;
+
+        case SIOCDARP:
+            if (!Process::current()->is_superuser())
+                return -EPERM;
+            if (arp_req.arp_pa.sa_family != AF_INET)
+                return -EAFNOSUPPORT;
+            update_arp_table(IPv4Address(((sockaddr_in&)arp_req.arp_pa).sin_addr.s_addr), *(MACAddress*)&arp_req.arp_ha.sa_data[0], UpdateArp::Delete);
+            return 0;
+        }
+
+        return -EINVAL;
+    };
+
     auto ioctl_interface = [request, arg]() {
         ifreq* user_ifr = (ifreq*)arg;
         ifreq ifr;
@@ -730,6 +756,10 @@ int IPv4Socket::ioctl(FileDescription&, unsigned request, FlatPtr arg)
     case SIOCADDRT:
     case SIOCDELRT:
         return ioctl_route();
+
+    case SIOCSARP:
+    case SIOCDARP:
+        return ioctl_arp();
     }
 
     return -EINVAL;
diff --git a/Kernel/UnixTypes.h b/Kernel/UnixTypes.h
index 53ba25595c..88a69f5070 100644
--- a/Kernel/UnixTypes.h
+++ b/Kernel/UnixTypes.h
@@ -691,6 +691,14 @@ struct rtentry {
 #define AT_FDCWD -100
 #define AT_SYMLINK_NOFOLLOW 0x100
 
+struct arpreq {
+    struct sockaddr arp_pa;      /* protocol address */
+    struct sockaddr arp_ha;      /* hardware address */
+    struct sockaddr arp_netmask; /* netmask of protocol address */
+    int arp_flags;               /* flags */
+    char arp_dev[16];
+};
+
 #define PURGE_ALL_VOLATILE 0x1
 #define PURGE_ALL_CLEAN_INODE 0x2
 
diff --git a/Userland/Libraries/LibC/net/route.h b/Userland/Libraries/LibC/net/route.h
index 27cf9596c6..aa82d81c92 100644
--- a/Userland/Libraries/LibC/net/route.h
+++ b/Userland/Libraries/LibC/net/route.h
@@ -18,3 +18,11 @@ struct rtentry {
 
 #define RTF_UP 0x1      /* do not delete the route */
 #define RTF_GATEWAY 0x2 /* the route is a gateway and not an end host */
+
+struct arpreq {
+    struct sockaddr arp_pa;      /* protocol address */
+    struct sockaddr arp_ha;      /* hardware address */
+    struct sockaddr arp_netmask; /* netmask of protocol address */
+    int arp_flags;               /* flags */
+    char arp_dev[16];
+};
diff --git a/Userland/Libraries/LibC/sys/ioctl_numbers.h b/Userland/Libraries/LibC/sys/ioctl_numbers.h
index 234a5decd2..0e24317ac9 100644
--- a/Userland/Libraries/LibC/sys/ioctl_numbers.h
+++ b/Userland/Libraries/LibC/sys/ioctl_numbers.h
@@ -79,6 +79,8 @@ enum IOCtlNumber {
     SIOCGIFCONF,
     SIOCADDRT,
     SIOCDELRT,
+    SIOCSARP,
+    SIOCDARP,
     FIBMAP,
     FIONBIO,
 };
@@ -117,5 +119,7 @@ enum IOCtlNumber {
 #define SIOCGIFCONF SIOCGIFCONF
 #define SIOCADDRT SIOCADDRT
 #define SIOCDELRT SIOCDELRT
+#define SIOCSARP SIOCSARP
+#define SIOCDARP SIOCDARP
 #define FIBMAP FIBMAP
 #define FIONBIO FIONBIO