Kernel: Add so_error to keep track of the socket's error state

This sets the m_so_error variable every time the socket returns an
error.

6 files changed, 88 insertions, 78 deletions

diff --git a/Kernel/Net/IPv4Socket.cpp b/Kernel/Net/IPv4Socket.cpp
index 4ccabe7022..35ee2f9646 100644
--- a/Kernel/Net/IPv4Socket.cpp
+++ b/Kernel/Net/IPv4Socket.cpp
@@ -108,20 +108,20 @@ KResult IPv4Socket::bind(Userspace<const sockaddr*> user_address, socklen_t addr
 {
     VERIFY(setup_state() == SetupState::Unstarted);
     if (address_size != sizeof(sockaddr_in))
-        return EINVAL;
+        return set_so_error(EINVAL);
 
     sockaddr_in address;
     if (!copy_from_user(&address, user_address, sizeof(sockaddr_in)))
-        return EFAULT;
+        return set_so_error(EFAULT);
 
     if (address.sin_family != AF_INET)
-        return EINVAL;
+        return set_so_error(EINVAL);
 
     auto requested_local_port = ntohs(address.sin_port);
     if (!Process::current()->is_superuser()) {
         if (requested_local_port > 0 && requested_local_port < 1024) {
             dbgln("UID {} attempted to bind {} to port {}", Process::current()->uid(), class_name(), requested_local_port);
-            return EACCES;
+            return set_so_error(EACCES);
         }
     }
 
@@ -152,19 +152,19 @@ KResult IPv4Socket::listen(size_t backlog)
 KResult IPv4Socket::connect(FileDescription& description, Userspace<const sockaddr*> address, socklen_t address_size, ShouldBlock should_block)
 {
     if (address_size != sizeof(sockaddr_in))
-        return EINVAL;
+        return set_so_error(EINVAL);
     u16 sa_family_copy;
     auto* user_address = reinterpret_cast<const sockaddr*>(address.unsafe_userspace_ptr());
     if (!copy_from_user(&sa_family_copy, &user_address->sa_family, sizeof(u16)))
-        return EFAULT;
+        return set_so_error(EFAULT);
     if (sa_family_copy != AF_INET)
-        return EINVAL;
+        return set_so_error(EINVAL);
     if (m_role == Role::Connected)
-        return EISCONN;
+        return set_so_error(EISCONN);
 
     sockaddr_in safe_address;
     if (!copy_from_user(&safe_address, (const sockaddr_in*)user_address, sizeof(sockaddr_in)))
-        return EFAULT;
+        return set_so_error(EFAULT);
 
     m_peer_address = IPv4Address((const u8*)&safe_address.sin_addr.s_addr);
     if (m_peer_address == IPv4Address { 0, 0, 0, 0 })
@@ -205,16 +205,16 @@ KResultOr<size_t> IPv4Socket::sendto(FileDescription&, const UserOrKernelBuffer&
     MutexLocker locker(lock());
 
     if (addr && addr_length != sizeof(sockaddr_in))
-        return EINVAL;
+        return set_so_error(EINVAL);
 
     if (addr) {
         sockaddr_in ia;
         if (!copy_from_user(&ia, Userspace<const sockaddr_in*>(addr.ptr())))
-            return EFAULT;
+            return set_so_error(EFAULT);
 
         if (ia.sin_family != AF_INET) {
             dmesgln("sendto: Bad address family: {} is not AF_INET", ia.sin_family);
-            return EAFNOSUPPORT;
+            return set_so_error(EAFNOSUPPORT);
         }
 
         m_peer_address = IPv4Address((const u8*)&ia.sin_addr.s_addr);
@@ -222,11 +222,11 @@ KResultOr<size_t> IPv4Socket::sendto(FileDescription&, const UserOrKernelBuffer&
     }
 
     if (!is_connected() && m_peer_address.is_zero())
-        return EPIPE;
+        return set_so_error(EPIPE);
 
     auto routing_decision = route_to(m_peer_address, m_local_address, bound_interface());
     if (routing_decision.is_zero())
-        return EHOSTUNREACH;
+        return set_so_error(EHOSTUNREACH);
 
     if (m_local_address.to_u32() == 0)
         m_local_address = routing_decision.adapter->ipv4_address();
@@ -241,12 +241,12 @@ KResultOr<size_t> IPv4Socket::sendto(FileDescription&, const UserOrKernelBuffer&
         data_length = min(data_length, routing_decision.adapter->mtu() - ipv4_payload_offset);
         auto packet = routing_decision.adapter->acquire_packet_buffer(ipv4_payload_offset + data_length);
         if (!packet)
-            return ENOMEM;
+            return set_so_error(ENOMEM);
         routing_decision.adapter->fill_in_ipv4_header(*packet, local_address(), routing_decision.next_hop,
             m_peer_address, (IPv4Protocol)protocol(), data_length, m_ttl);
         if (!data.read(packet->buffer->data() + ipv4_payload_offset, data_length)) {
             routing_decision.adapter->release_packet_buffer(*packet);
-            return EFAULT;
+            return set_so_error(EFAULT);
         }
         routing_decision.adapter->send_packet(packet->bytes());
         routing_decision.adapter->release_packet_buffer(*packet);
@@ -266,7 +266,7 @@ KResultOr<size_t> IPv4Socket::receive_byte_buffered(FileDescription& description
         if (protocol_is_disconnected())
             return 0;
         if (!description.is_blocking())
-            return EAGAIN;
+            return set_so_error(EAGAIN);
 
         locker.unlock();
         auto unblocked_flags = BlockFlags::None;
@@ -275,10 +275,10 @@ KResultOr<size_t> IPv4Socket::receive_byte_buffered(FileDescription& description
 
         if (!has_flag(unblocked_flags, BlockFlags::Read)) {
             if (res.was_interrupted())
-                return EINTR;
+                return set_so_error(EINTR);
 
             // Unblocked due to timeout.
-            return EAGAIN;
+            return set_so_error(EAGAIN);
         }
     }
 
@@ -306,7 +306,7 @@ KResultOr<size_t> IPv4Socket::receive_packet_buffered(FileDescription& descripti
             if (protocol_is_disconnected())
                 return 0;
             if (!description.is_blocking())
-                return EAGAIN;
+                return set_so_error(EAGAIN);
         }
 
         if (!m_receive_queue.is_empty()) {
@@ -336,10 +336,10 @@ KResultOr<size_t> IPv4Socket::receive_packet_buffered(FileDescription& descripti
 
         if (!has_flag(unblocked_flags, BlockFlags::Read)) {
             if (res.was_interrupted())
-                return EINTR;
+                return set_so_error(EINTR);
 
             // Unblocked due to timeout.
-            return EAGAIN;
+            return set_so_error(EAGAIN);
         }
         VERIFY(m_can_read);
         VERIFY(!m_receive_queue.is_empty());
@@ -369,18 +369,18 @@ KResultOr<size_t> IPv4Socket::receive_packet_buffered(FileDescription& descripti
         out_addr.sin_family = AF_INET;
         Userspace<sockaddr_in*> dest_addr = addr.ptr();
         if (!copy_to_user(dest_addr, &out_addr))
-            return EFAULT;
+            return set_so_error(EFAULT);
 
         socklen_t out_length = sizeof(sockaddr_in);
         VERIFY(addr_length);
         if (!copy_to_user(addr_length, &out_length))
-            return EFAULT;
+            return set_so_error(EFAULT);
     }
 
     if (type() == SOCK_RAW) {
         size_t bytes_written = min(packet.data.value().size(), buffer_length);
         if (!buffer.write(packet.data.value().data(), bytes_written))
-            return EFAULT;
+            return set_so_error(EFAULT);
         return bytes_written;
     }
 
@@ -392,9 +392,9 @@ KResultOr<size_t> IPv4Socket::recvfrom(FileDescription& description, UserOrKerne
     if (user_addr_length) {
         socklen_t addr_length;
         if (!copy_from_user(&addr_length, user_addr_length.unsafe_userspace_ptr()))
-            return EFAULT;
+            return set_so_error(EFAULT);
         if (addr_length < sizeof(sockaddr_in))
-            return EINVAL;
+            return set_so_error(EINVAL);
     }
 
     dbgln_if(IPV4_SOCKET_DEBUG, "recvfrom: type={}, local_port={}", type(), local_port());
diff --git a/Kernel/Net/LocalSocket.cpp b/Kernel/Net/LocalSocket.cpp
index 5e8dc330f5..8041c8d459 100644
--- a/Kernel/Net/LocalSocket.cpp
+++ b/Kernel/Net/LocalSocket.cpp
@@ -122,14 +122,14 @@ KResult LocalSocket::bind(Userspace<const sockaddr*> user_address, socklen_t add
 {
     VERIFY(setup_state() == SetupState::Unstarted);
     if (address_size != sizeof(sockaddr_un))
-        return EINVAL;
+        return set_so_error(EINVAL);
 
     sockaddr_un address;
     if (!copy_from_user(&address, user_address, sizeof(sockaddr_un)))
-        return EFAULT;
+        return set_so_error(EFAULT);
 
     if (address.sun_family != AF_LOCAL)
-        return EINVAL;
+        return set_so_error(EINVAL);
 
     auto path = String(address.sun_path, strnlen(address.sun_path, sizeof(address.sun_path)));
 
@@ -140,7 +140,7 @@ KResult LocalSocket::bind(Userspace<const sockaddr*> user_address, socklen_t add
     auto result = VirtualFileSystem::the().open(path, O_CREAT | O_EXCL | O_NOFOLLOW_NOERROR, mode, Process::current()->current_directory(), owner);
     if (result.is_error()) {
         if (result.error() == -EEXIST)
-            return EADDRINUSE;
+            return set_so_error(EADDRINUSE);
         return result.error();
     }
 
@@ -148,7 +148,7 @@ KResult LocalSocket::bind(Userspace<const sockaddr*> user_address, socklen_t add
 
     VERIFY(file->inode());
     if (!file->inode()->bind_socket(*this))
-        return EADDRINUSE;
+        return set_so_error(EADDRINUSE);
 
     m_file = move(file);
 
@@ -161,33 +161,33 @@ KResult LocalSocket::connect(FileDescription& description, Userspace<const socka
 {
     VERIFY(!m_bound);
     if (address_size != sizeof(sockaddr_un))
-        return EINVAL;
+        return set_so_error(EINVAL);
     u16 sa_family_copy;
     auto* user_address = reinterpret_cast<const sockaddr*>(address.unsafe_userspace_ptr());
     if (!copy_from_user(&sa_family_copy, &user_address->sa_family, sizeof(u16)))
-        return EFAULT;
+        return set_so_error(EFAULT);
     if (sa_family_copy != AF_LOCAL)
-        return EINVAL;
+        return set_so_error(EINVAL);
     if (is_connected())
-        return EISCONN;
+        return set_so_error(EISCONN);
 
     const auto& local_address = *reinterpret_cast<const sockaddr_un*>(user_address);
     char safe_address[sizeof(local_address.sun_path) + 1] = { 0 };
     if (!copy_from_user(&safe_address[0], &local_address.sun_path[0], sizeof(safe_address) - 1))
-        return EFAULT;
+        return set_so_error(EFAULT);
     safe_address[sizeof(safe_address) - 1] = '\0';
 
     dbgln_if(LOCAL_SOCKET_DEBUG, "LocalSocket({}) connect({})", this, safe_address);
 
     auto description_or_error = VirtualFileSystem::the().open(safe_address, O_RDWR, 0, Process::current()->current_directory());
     if (description_or_error.is_error())
-        return ECONNREFUSED;
+        return set_so_error(ECONNREFUSED);
 
     m_file = move(description_or_error.value());
 
     VERIFY(m_file->inode());
     if (!m_file->inode()->socket())
-        return ECONNREFUSED;
+        return set_so_error(ECONNREFUSED);
 
     m_address.sun_family = sa_family_copy;
     memcpy(m_address.sun_path, safe_address, sizeof(m_address.sun_path));
@@ -210,14 +210,14 @@ KResult LocalSocket::connect(FileDescription& description, Userspace<const socka
     auto unblock_flags = Thread::FileDescriptionBlocker::BlockFlags::None;
     if (Thread::current()->block<Thread::ConnectBlocker>({}, description, unblock_flags).was_interrupted()) {
         set_connect_side_role(Role::None);
-        return EINTR;
+        return set_so_error(EINTR);
     }
 
     dbgln_if(LOCAL_SOCKET_DEBUG, "LocalSocket({}) connect({}) status is {}", this, safe_address, to_string(setup_state()));
 
     if (!has_flag(unblock_flags, Thread::FileDescriptionBlocker::BlockFlags::Connect)) {
         set_connect_side_role(Role::None);
-        return ECONNREFUSED;
+        return set_so_error(ECONNREFUSED);
     }
     set_connect_side_role(Role::Connected);
     return KSuccess;
@@ -227,7 +227,7 @@ KResult LocalSocket::listen(size_t backlog)
 {
     MutexLocker locker(lock());
     if (type() != SOCK_STREAM)
-        return EOPNOTSUPP;
+        return set_so_error(EOPNOTSUPP);
     set_backlog(backlog);
     auto previous_role = m_role;
     m_role = Role::Listener;
@@ -300,10 +300,10 @@ bool LocalSocket::can_write(const FileDescription& description, size_t) const
 KResultOr<size_t> LocalSocket::sendto(FileDescription& description, const UserOrKernelBuffer& data, size_t data_size, int, Userspace<const sockaddr*>, socklen_t)
 {
     if (!has_attached_peer(description))
-        return EPIPE;
+        return set_so_error(EPIPE);
     auto* socket_buffer = send_buffer_for(description);
     if (!socket_buffer)
-        return EINVAL;
+        return set_so_error(EINVAL);
     auto nwritten_or_error = socket_buffer->write(data, data_size);
     if (!nwritten_or_error.is_error() && nwritten_or_error.value() > 0)
         Thread::current()->did_unix_socket_write(nwritten_or_error.value());
@@ -334,17 +334,18 @@ KResultOr<size_t> LocalSocket::recvfrom(FileDescription& description, UserOrKern
 {
     auto* socket_buffer = receive_buffer_for(description);
     if (!socket_buffer)
-        return EINVAL;
+        return set_so_error(EINVAL);
     if (!description.is_blocking()) {
         if (socket_buffer->is_empty()) {
             if (!has_attached_peer(description))
                 return 0;
-            return EAGAIN;
+            return set_so_error(EAGAIN);
         }
     } else if (!can_read(description, 0)) {
         auto unblock_flags = Thread::FileDescriptionBlocker::BlockFlags::None;
-        if (Thread::current()->block<Thread::ReadBlocker>({}, description, unblock_flags).was_interrupted())
-            return EINTR;
+        if (Thread::current()->block<Thread::ReadBlocker>({}, description, unblock_flags).was_interrupted()) {
+            return set_so_error(EINTR);
+        }
     }
     if (!has_attached_peer(description) && socket_buffer->is_empty())
         return 0;
@@ -447,7 +448,7 @@ KResult LocalSocket::chown(FileDescription&, uid_t uid, gid_t gid)
 
     auto current_process = Process::current();
     if (!current_process->is_superuser() && (current_process->euid() != uid || !current_process->in_group(gid)))
-        return EPERM;
+        return set_so_error(EPERM);
 
     m_prebind_uid = uid;
     m_prebind_gid = gid;
@@ -479,13 +480,13 @@ KResult LocalSocket::sendfd(const FileDescription& socket_description, FileDescr
     MutexLocker locker(lock());
     auto role = this->role(socket_description);
     if (role != Role::Connected && role != Role::Accepted)
-        return EINVAL;
+        return set_so_error(EINVAL);
     auto& queue = sendfd_queue_for(socket_description);
     // FIXME: Figure out how we should limit this properly.
     if (queue.size() > 128)
-        return EBUSY;
+        return set_so_error(EBUSY);
     if (!queue.try_append(move(passing_description)))
-        return ENOMEM;
+        return set_so_error(ENOMEM);
     return KSuccess;
 }
 
@@ -494,11 +495,11 @@ KResultOr<NonnullRefPtr<FileDescription>> LocalSocket::recvfd(const FileDescript
     MutexLocker locker(lock());
     auto role = this->role(socket_description);
     if (role != Role::Connected && role != Role::Accepted)
-        return EINVAL;
+        return set_so_error(EINVAL);
     auto& queue = recvfd_queue_for(socket_description);
     if (queue.is_empty()) {
         // FIXME: Figure out the perfect error code for this.
-        return EAGAIN;
+        return set_so_error(EAGAIN);
     }
     return queue.take_first();
 }
diff --git a/Kernel/Net/Socket.cpp b/Kernel/Net/Socket.cpp
index e7bc17a581..d7a69fa456 100644
--- a/Kernel/Net/Socket.cpp
+++ b/Kernel/Net/Socket.cpp
@@ -71,9 +71,9 @@ KResult Socket::queue_connection_from(NonnullRefPtr<Socket> peer)
     dbgln_if(SOCKET_DEBUG, "Socket({}) queueing connection", this);
     MutexLocker locker(m_lock);
     if (m_pending.size() >= m_backlog)
-        return ECONNREFUSED;
+        return set_so_error(ECONNREFUSED);
     if (!m_pending.try_append(peer))
-        return ENOMEM;
+        return set_so_error(ENOMEM);
     evaluate_block_conditions();
     return KSuccess;
 }
@@ -235,7 +235,7 @@ KResultOr<size_t> Socket::read(FileDescription& description, u64, UserOrKernelBu
 KResultOr<size_t> Socket::write(FileDescription& description, u64, const UserOrKernelBuffer& data, size_t size)
 {
     if (is_shut_down_for_writing())
-        return EPIPE;
+        return set_so_error(EPIPE);
     return sendto(description, data, size, 0, {}, 0);
 }
 
@@ -243,9 +243,9 @@ KResult Socket::shutdown(int how)
 {
     MutexLocker locker(lock());
     if (type() == SOCK_STREAM && !is_connected())
-        return ENOTCONN;
+        return set_so_error(ENOTCONN);
     if (m_role == Role::Listener)
-        return ENOTCONN;
+        return set_so_error(ENOTCONN);
     if (!m_shut_down_for_writing && (how & SHUT_WR))
         shut_down_for_writing();
     if (!m_shut_down_for_reading && (how & SHUT_RD))
diff --git a/Kernel/Net/Socket.h b/Kernel/Net/Socket.h
index 939ee41fb8..d175001a35 100644
--- a/Kernel/Net/Socket.h
+++ b/Kernel/Net/Socket.h
@@ -130,6 +130,13 @@ protected:
 
     Role m_role { Role::None };
 
+    KResult so_error() const { return m_so_error; }
+    KResult set_so_error(KResult error)
+    {
+        m_so_error = error;
+        return error;
+    }
+
 protected:
     ucred m_origin { 0, 0, 0 };
     ucred m_acceptor { 0, 0, 0 };
@@ -154,6 +161,8 @@ private:
     Time m_send_timeout {};
     int m_timestamp { 0 };
 
+    KResult m_so_error { KSuccess };
+
     NonnullRefPtrVector<Socket> m_pending;
 };
 
diff --git a/Kernel/Net/TCPSocket.cpp b/Kernel/Net/TCPSocket.cpp
index c03e631509..c1ea1abd8c 100644
--- a/Kernel/Net/TCPSocket.cpp
+++ b/Kernel/Net/TCPSocket.cpp
@@ -171,7 +171,7 @@ KResultOr<size_t> TCPSocket::protocol_receive(ReadonlyBytes raw_ipv4_packet, Use
     dbgln_if(TCP_SOCKET_DEBUG, "payload_size {}, will it fit in {}?", payload_size, buffer_size);
     VERIFY(buffer_size >= payload_size);
     if (!buffer.write(tcp_packet.payload(), payload_size))
-        return EFAULT;
+        return set_so_error(EFAULT);
     return payload_size;
 }
 
@@ -179,7 +179,7 @@ KResultOr<size_t> TCPSocket::protocol_send(const UserOrKernelBuffer& data, size_
 {
     RoutingDecision routing_decision = route_to(peer_address(), local_address(), bound_interface());
     if (routing_decision.is_zero())
-        return EHOSTUNREACH;
+        return set_so_error(EHOSTUNREACH);
     size_t mss = routing_decision.adapter->mtu() - sizeof(IPv4Packet) - sizeof(TCPPacket);
     data_length = min(data_length, mss);
     int err = send_tcp_packet(TCPFlags::PUSH | TCPFlags::ACK, &data, data_length, &routing_decision);
@@ -199,7 +199,7 @@ KResult TCPSocket::send_tcp_packet(u16 flags, const UserOrKernelBuffer* payload,
 {
     RoutingDecision routing_decision = user_routing_decision ? *user_routing_decision : route_to(peer_address(), local_address(), bound_interface());
     if (routing_decision.is_zero())
-        return EHOSTUNREACH;
+        return set_so_error(EHOSTUNREACH);
 
     auto ipv4_payload_offset = routing_decision.adapter->ipv4_payload_offset();
 
@@ -209,7 +209,7 @@ KResult TCPSocket::send_tcp_packet(u16 flags, const UserOrKernelBuffer* payload,
     const size_t buffer_size = ipv4_payload_offset + tcp_header_size + payload_size;
     auto packet = routing_decision.adapter->acquire_packet_buffer(buffer_size);
     if (!packet)
-        return ENOMEM;
+        return set_so_error(ENOMEM);
     routing_decision.adapter->fill_in_ipv4_header(*packet, local_address(),
         routing_decision.next_hop, peer_address(), IPv4Protocol::TCP,
         buffer_size - ipv4_payload_offset, ttl());
@@ -231,7 +231,7 @@ KResult TCPSocket::send_tcp_packet(u16 flags, const UserOrKernelBuffer* payload,
 
     if (payload && !payload->read(tcp_packet.payload(), payload_size)) {
         routing_decision.adapter->release_packet_buffer(*packet);
-        return EFAULT;
+        return set_so_error(EFAULT);
     }
 
     if (flags & TCPFlags::SYN) {
@@ -370,7 +370,7 @@ KResult TCPSocket::protocol_bind()
     if (has_specific_local_address() && !m_adapter) {
         m_adapter = NetworkingManagement::the().from_ipv4_address(local_address());
         if (!m_adapter)
-            return EADDRNOTAVAIL;
+            return set_so_error(EADDRNOTAVAIL);
     }
 
     return KSuccess;
@@ -386,7 +386,7 @@ KResult TCPSocket::protocol_listen(bool did_allocate_port)
             return true;
         });
         if (!ok)
-            return EADDRINUSE;
+            return set_so_error(EADDRINUSE);
     }
 
     set_direction(Direction::Passive);
@@ -401,7 +401,7 @@ KResult TCPSocket::protocol_connect(FileDescription& description, ShouldBlock sh
 
     auto routing_decision = route_to(peer_address(), local_address());
     if (routing_decision.is_zero())
-        return EHOSTUNREACH;
+        return set_so_error(EHOSTUNREACH);
     if (!has_specific_local_address())
         set_local_address(routing_decision.adapter->ipv4_address());
 
@@ -425,20 +425,20 @@ KResult TCPSocket::protocol_connect(FileDescription& description, ShouldBlock sh
         locker.unlock();
         auto unblock_flags = Thread::FileBlocker::BlockFlags::None;
         if (Thread::current()->block<Thread::ConnectBlocker>({}, description, unblock_flags).was_interrupted())
-            return EINTR;
+            return set_so_error(EINTR);
         locker.lock();
         VERIFY(setup_state() == SetupState::Completed);
         if (has_error()) { // TODO: check unblock_flags
             m_role = Role::None;
             if (error() == TCPSocket::Error::RetransmitTimeout)
-                return ETIMEDOUT;
+                return set_so_error(ETIMEDOUT);
             else
-                return ECONNREFUSED;
+                return set_so_error(ECONNREFUSED);
         }
         return KSuccess;
     }
 
-    return EINPROGRESS;
+    return set_so_error(EINPROGRESS);
 }
 
 KResultOr<u16> TCPSocket::protocol_allocate_local_port()
@@ -464,7 +464,7 @@ KResultOr<u16> TCPSocket::protocol_allocate_local_port()
             if (port == first_scan_port)
                 break;
         }
-        return EADDRINUSE;
+        return set_so_error(EADDRINUSE);
     });
 }
 
diff --git a/Kernel/Net/UDPSocket.cpp b/Kernel/Net/UDPSocket.cpp
index fc6217ebf2..170663fc32 100644
--- a/Kernel/Net/UDPSocket.cpp
+++ b/Kernel/Net/UDPSocket.cpp
@@ -69,7 +69,7 @@ KResultOr<size_t> UDPSocket::protocol_receive(ReadonlyBytes raw_ipv4_packet, Use
     VERIFY(udp_packet.length() >= sizeof(UDPPacket)); // FIXME: This should be rejected earlier.
     size_t read_size = min(buffer_size, udp_packet.length() - sizeof(UDPPacket));
     if (!buffer.write(udp_packet.payload(), read_size))
-        return EFAULT;
+        return set_so_error(EFAULT);
     return read_size;
 }
 
@@ -77,20 +77,20 @@ KResultOr<size_t> UDPSocket::protocol_send(const UserOrKernelBuffer& data, size_
 {
     auto routing_decision = route_to(peer_address(), local_address(), bound_interface());
     if (routing_decision.is_zero())
-        return EHOSTUNREACH;
+        return set_so_error(EHOSTUNREACH);
     auto ipv4_payload_offset = routing_decision.adapter->ipv4_payload_offset();
     data_length = min(data_length, routing_decision.adapter->mtu() - ipv4_payload_offset - sizeof(UDPPacket));
     const size_t udp_buffer_size = sizeof(UDPPacket) + data_length;
     auto packet = routing_decision.adapter->acquire_packet_buffer(ipv4_payload_offset + udp_buffer_size);
     if (!packet)
-        return ENOMEM;
+        return set_so_error(ENOMEM);
     memset(packet->buffer->data() + ipv4_payload_offset, 0, sizeof(UDPPacket));
     auto& udp_packet = *reinterpret_cast<UDPPacket*>(packet->buffer->data() + ipv4_payload_offset);
     udp_packet.set_source_port(local_port());
     udp_packet.set_destination_port(peer_port());
     udp_packet.set_length(udp_buffer_size);
     if (!data.read(udp_packet.payload(), data_length))
-        return EFAULT;
+        return set_so_error(EFAULT);
 
     routing_decision.adapter->fill_in_ipv4_header(*packet, local_address(), routing_decision.next_hop,
         peer_address(), IPv4Protocol::UDP, udp_buffer_size, ttl());
@@ -126,7 +126,7 @@ KResultOr<u16> UDPSocket::protocol_allocate_local_port()
             if (port == first_scan_port)
                 break;
         }
-        return EADDRINUSE;
+        return set_so_error(EADDRINUSE);
     });
 }
 
@@ -134,7 +134,7 @@ KResult UDPSocket::protocol_bind()
 {
     return sockets_by_port().with_exclusive([&](auto& table) -> KResult {
         if (table.contains(local_port()))
-            return EADDRINUSE;
+            return set_so_error(EADDRINUSE);
         table.set(local_port(), this);
         return KSuccess;
     });