src/net/client_factory.cpp

@@ -12,35 +12,11 @@
 #include "net/udp_client.hpp"
 
 namespace rmrf::net {
-    
-    [[nodiscard]] socketaddr get_own_address_after_connect(const auto_fd& socket) {
-        socketaddr own_address;
-        socklen_t sa_local_len = sizeof(sockaddr_storage);
-
-        if (getsockname(socket.get(), own_address.ptr(), &sa_local_len) == 0) {
-            // Update length field after the internal structure was modified
-            // TODO: Maybe make this an internal method in socketaddr to update the size
-            own_address = own_address.ptr();
-        } else {
-            switch(errno) {
-                case EBADF:
-                case ENOTSOCK:
-                    throw netio_exception("Invalid file descriptor provided to obtain own address. ERRNO: " + std::to_string(errno));
-                case EFAULT:
-                case EINVAL:
-                    throw netio_exception("Invlid data structure for information retrival of own socket address provided. ERRNO: " + std::to_string(errno));
-                case ENOBUFS:
-                    throw netio_exception("Kernel temporarily out of buffer space to store own address informatio.n ERRNO:." + std::to_string(errno));
-                default:
-                    throw netio_exception("Unexpected error while requesting own socket address. ERRNO: " + std::to_string(errno));
-            }
-        }
-        return own_address;
-    }
-    
+
     [[nodiscard]] std::unique_ptr<udp_client> client_factory_construct_udp_client(const socketaddr& socket_identifier, connection_client::incomming_data_cb cb) {
         const auto family = socket_identifier.family();
 
+        // TODO maybe implement also unix sockets with SOCK_SEQPACKET if we need them
         if (!(family == AF_INET || family == AF_INET6)) {
             std::stringstream ss;
             ss << "Invalid IP address family. (" <<  family << ")";
@@ -61,15 +37,31 @@ namespace rmrf::net {
         }
         return c;
     }
-    
-    [[nodiscard]] std::unique_ptr<tcp_client> client_factory_construct_tcp_client(const socketaddr& socket_identifier, connection_client::incomming_data_cb cb) {
+
+    [[nodiscard]] std::unique_ptr<connection_client> client_factory_construct_tcp_client(const socketaddr& socket_identifier, connection_client::incomming_data_cb cb) {
+        if (auto f = socket_identifier.family(); f != AF_INET6 && f != AF_INET) {
+            throw netio_exception("Expected TCP socket address over IP");
+        }
+
+        return client_factory_construct_stream_client(socket_identifier, cb);
+    }
+
+    [[nodiscard]] std::unique_ptr<connection_client> client_factory_construct_unix_client(const socketaddr& socket_identifier, connection_client::incomming_data_cb cb) {
+        if (socket_identifier.family() != AF_UNIX) {
+            throw netio_exception("Expected UNIX domain socket address as target");
+        }
+
+        return client_factory_construct_stream_client(socket_identifier, cb);
+    }
+
+    [[nodiscard]] std::unique_ptr<connection_client> client_factory_construct_stream_client(const socketaddr& socket_identifier, connection_client::incomming_data_cb cb) {
         auto_fd socket_candidate{socket(socket_identifier.family(), SOCK_STREAM, 0)};
-        
+
         if (socket_candidate.valid()) {
             if (connect(socket_candidate.get(), socket_identifier.ptr(), socket_identifier.size()) == 0) {
                 make_socket_nonblocking(socket_candidate);
-                const auto own_address = get_own_address_after_connect(socket_candidate);
-                
+                const auto own_address = socket_identifier.family() != AF_UNIX ? get_own_address_after_connect(socket_candidate) : socketaddr{};
+
                 // TODO create client object using socket_candidate, own_address and socket_identifier as remote address
                 auto c = std::make_unique<tcp_client>(nullptr, std::move(socket_candidate), own_address, socket_identifier);
                 if(cb) {
@@ -80,21 +72,20 @@ namespace rmrf::net {
         }
         return nullptr;
     }
-    
+
     [[nodiscard]] std::unique_ptr<connection_client> connect(const socketaddr& address, const socket_t& type) {
         switch(type) {
             case socket_t::TCP:
                 return client_factory_construct_tcp_client(address);
+            case socket_t::UNIX:
+                return client_factory_construct_unix_client(address);
             case socket_t::UDP:
                 return client_factory_construct_udp_client(address);
-            case socket_t::UNIX:
-                // TODO implement
-                return nullptr;
             default:
                 return nullptr;
         }
     }
-    
+
     socket_t guess_socket_type_from_address(const socketaddr& address) {
         switch(address.family()) {
             case AF_INET:
@@ -117,11 +108,11 @@ namespace rmrf::net {
 
     [[nodiscard]] std::unique_ptr<connection_client> connect(const std::string& peer_address, const std::string& service, int ip_addr_family) {
         const auto candidates = get_socketaddr_list(peer_address, service);
-        
+
         if (candidates.empty()) {
             throw netio_exception("Unable to find suitable connection candidate.");
         }
-        
+
         if (ip_addr_family == AF_UNSPEC) {
             ip_addr_family = candidates.front().family();
         }
@@ -129,20 +120,21 @@ namespace rmrf::net {
         if (!(ip_addr_family == AF_INET || ip_addr_family == AF_INET6 || ip_addr_family == AF_UNIX)) {
             throw netio_exception("Invalid IP address family.");
         }
-        
+
         std::unique_ptr<connection_client> latest_client;
-        
+
         for(const auto& current_connection_candidate : candidates) {
             if(latest_client = connect(current_connection_candidate, guess_socket_type_from_address(current_connection_candidate));
                 latest_client) {
                 break;
             }
         }
-        
+
         if (!latest_client) {
             throw netio_exception("Unable to find suitable connection candidate.");
         }
-        
+
         return latest_client;
     }
- }
+
+}

src/net/client_factory.hpp

@@ -10,16 +10,9 @@
 namespace rmrf::net {
     
     [[nodiscard]] std::unique_ptr<udp_client> client_factory_construct_udp_client(const socketaddr& socket_identifier, connection_client::incomming_data_cb cb = nullptr);
-    [[nodiscard]] std::unique_ptr<tcp_client> client_factory_construct_tcp_client(const socketaddr& socket_identifier, connection_client::incomming_data_cb cb = nullptr);
-    
-    /**
-     * This method queries the remote address of a connected client. Please note that only TCP sockets are supported
-     * at the moment. This operation will fail if an unsupported socket type is provided.
-     * @brief Get the address of the connected remote client
-     * @param socket The socket representing the client
-     * @return The remote socketaddr pair
-     */
-    [[nodiscard]] socketaddr get_own_address_after_connect(const auto_fd& socket);
+    [[nodiscard]] std::unique_ptr<connection_client> client_factory_construct_tcp_client(const socketaddr& socket_identifier, connection_client::incomming_data_cb cb = nullptr);
+    [[nodiscard]] std::unique_ptr<connection_client> client_factory_construct_unix_client(const socketaddr& socket_identifier, connection_client::incomming_data_cb cb = nullptr);
+    [[nodiscard]] std::unique_ptr<connection_client> client_factory_construct_stream_client(const socketaddr& socket_identifier, connection_client::incomming_data_cb cb = nullptr);
     
     /**
      * This method directly connects to the given address and returns an invalid pointer if it fails.

src/net/connection_client.cpp

@@ -15,6 +15,7 @@ namespace rmrf::net {
 
         if (this->server_active) {
             io.stop();
+            this->net_socket.reset();
         }
 
         if (destructor_cb) {
@@ -31,7 +32,7 @@ namespace rmrf::net {
         }
 
         if (events & ::ev::READ) {
-            if(this->in_data_cb != nullptr)
+            if (this->in_data_cb != nullptr)
                 this->read_from_socket(w);
         }
 
@@ -52,19 +53,27 @@ namespace rmrf::net {
 
                 if (partial_write_allowed)
                     this->write_queue.push_front(buffer);
+
                 this->data_write_active = false;
             }
         }
 
         set_new_flags();
     }
-    
+
     void connection_client::stop_server() {
         this->server_active = false;
+        this->net_socket.reset();
+        this->write_queue.clear();
         io.stop();
+        async.stop();
     }
 
     void connection_client::set_incomming_data_callback(const incomming_data_cb &cb) {
+        if (!this->server_active) {
+            return;
+        }
+
         this->in_data_cb = cb;
         this->async.send();
     }

src/net/connection_client.hpp

@@ -52,7 +52,9 @@ private:
     ::ev::async async;
     ioqueue<iorecord> write_queue;
     const destructor_cb_type destructor_cb;
+protected:
     bool server_active = false;
+private:
     bool partial_write_allowed = true;
     bool data_write_active = false;
     
@@ -165,6 +167,10 @@ public:
         return this->rate_limit;
     }
 
+    [[nodiscard]] inline bool is_client_alive() {
+        return this->server_active;
+    }
+
 protected:
     /**
      * @brief Implement the read operation of the implemented service
@@ -195,8 +201,12 @@ private:
     void cb_async(::ev::async& w, int events);
     
     inline void set_new_flags() {
+        if (!this->server_active) {
+            return;
+        }
+
         auto new_flags = 0;
-        if(this->in_data_cb) {
+        if (this->in_data_cb) {
             new_flags |= ::ev::READ;
         }
         if (!this->write_queue.empty()) {

src/net/ioqueue.hpp

@@ -79,6 +79,10 @@ namespace rmrf::net {
         [[nodiscard]] inline std::deque<iorecord_type>::const_iterator end() const {
             return this->queue.end();
         }
+
+        void clear() {
+            this->queue.clear();
+        }
     };
 
 }

src/net/sock_address_factory.cpp

@@ -162,6 +162,17 @@ namespace rmrf::net {
     }
 
     std::list<socketaddr> get_socketaddr_list(const std::string &interface_description, const std::string &service_or_port, const socket_t socket_type) {
+        if (socket_type == socket_t::UNIX) {
+            sockaddr_un storage;
+            strncpy(storage.sun_path, interface_description.c_str(), sizeof(storage.sun_path));
+            // Required as the automatic initialization of sockaddr_un is broken on linux.
+            // This will be optimized out on platforms where it is not.
+            ((sockaddr*) &storage)->sa_family = AF_UNIX;
+            const socketaddr sa{storage};
+            std::list<socketaddr> l = {sa};
+            return l;
+        }
+
         int port = -1;
 
         try {
@@ -177,9 +188,9 @@ namespace rmrf::net {
             return l;
         }
 
+        // Attempt DNS lookup
         struct addrinfo hints = {};
-
-        struct addrinfo* addrs;
+        struct addrinfo* addrs = nullptr;
 
         hints.ai_family = AF_INET6;
         hints.ai_socktype = get_socket_type_hint(socket_type);
@@ -190,8 +201,10 @@ namespace rmrf::net {
             dns_error = getaddrinfo(interface_description.c_str(), NULL, &hints, &addrs);
 
             if (dns_error != 0) {
-                freeaddrinfo(addrs);
-                throw std::invalid_argument("Something went wrong with the DNS lookup. Error code: " + format_network_error(dns_error));
+                if (addrs != nullptr) {
+                    freeaddrinfo(addrs);
+                }
+                throw std::invalid_argument("Something went wrong with the DNS lookup. Error: " + format_network_error(dns_error));
             }
         }
 

src/net/socket_utils.cpp

@@ -11,4 +11,29 @@ namespace rmrf::net {
             throw netio_exception("Failed to set socket mode. fcntl resulted in error:" + std::to_string(errno));
         }
     }
+
+    [[nodiscard]] socketaddr get_own_address_after_connect(const auto_fd& socket) {
+        socketaddr own_address;
+        socklen_t sa_local_len = sizeof(sockaddr_storage);
+
+        if (getsockname(socket.get(), own_address.ptr(), &sa_local_len) == 0) {
+            // Update length field after the internal structure was modified
+            // TODO: Maybe make this an internal method in socketaddr to update the size
+            own_address = own_address.ptr();
+        } else {
+            switch(errno) {
+                case EBADF:
+                case ENOTSOCK:
+                    throw netio_exception("Invalid file descriptor provided to obtain own address. ERRNO: " + std::to_string(errno));
+                case EFAULT:
+                case EINVAL:
+                    throw netio_exception("Invlid data structure for information retrival of own socket address provided. ERRNO: " + std::to_string(errno));
+                case ENOBUFS:
+                    throw netio_exception("Kernel temporarily out of buffer space to store own address informatio.n ERRNO:." + std::to_string(errno));
+                default:
+                    throw netio_exception("Unexpected error while requesting own socket address. ERRNO: " + std::to_string(errno));
+            }
+        }
+        return own_address;
+    }
 }

src/net/socket_utils.hpp

 #pragma once
 
 #include "net/async_fd.hpp"
+#include "net/socketaddress.hpp"
 
 namespace rmrf::net {
     /**
@@ -8,4 +9,13 @@ namespace rmrf::net {
      * @param socket The socket to modify
      */
      void make_socket_nonblocking(auto_fd& socket);
+
+    /**
+     * This method queries the remote address of a connected client. Please note that only TCP sockets are supported
+     * at the moment. This operation will fail if an unsupported socket type is provided.
+     * @brief Get the address of the connected remote client
+     * @param socket The socket representing the client
+     * @return The remote socketaddr pair
+     */
+    [[nodiscard]] socketaddr get_own_address_after_connect(const auto_fd& socket);
 }

src/net/socketaddress.hpp

@@ -70,7 +70,7 @@ public:
     template <typename T, typename std::enable_if<has_field<T>::value, T>::type * = nullptr>
     explicit socketaddr(T *other) : addr{}, len{} {
         if (other->*(family_map<T>::sa_family_field) != family_map<T>::sa_family) {
-            throw netio_exception("Address family mismatch in sockaddr structure.");
+            throw netio_exception("Unable to construct socketaddr object. Address family mismatch in sockaddr structure.");
         }
 
         memcpy(&addr, other, sizeof(T));
@@ -88,7 +88,7 @@ public:
     template <typename T, typename std::enable_if<has_field<T>::value, T>::type * = nullptr>
     explicit socketaddr(const T& other) : addr{}, len{} {
         if (other.*(family_map<T>::sa_family_field) != family_map<T>::sa_family) {
-            throw netio_exception("Address family mismatch in sockaddr structure.");
+            throw netio_exception("Unable to construct socketaddr object from reference. Address family mismatch in sockaddr structure.");
         }
 
         memcpy(&addr, &other, sizeof(T));
@@ -98,7 +98,7 @@ public:
     template <typename T>
     socketaddr& operator=(const T *rhs) {
         if (rhs->*(family_map<T>::sa_family_field) != family_map<T>::sa_family) {
-            throw netio_exception("Address family mismatch in sockaddr structure.");
+            throw netio_exception("Unable to construct socketaddr object from rhs. Address family mismatch in sockaddr structure.");
         }
 
         memcpy(&addr, rhs, sizeof(T));

src/net/tcp_client.cpp

@@ -35,89 +35,6 @@ tcp_client::tcp_client(
     this->own_address = own_address_;
 }
 
-/*
-// TODO move to client_factory
-auto_fd tcp_client::get_connection(const std::string& peer_address_, const std::string& service_or_port, int ip_addr_family) {
-    std::list<socketaddr> connection_candidates = get_socketaddr_list(peer_address_, service_or_port, socket_t::TCP);
-
-    if (ip_addr_family == AF_UNSPEC) {
-        ip_addr_family = connection_candidates.front().family();
-    }
-
-    if (!(ip_addr_family == AF_INET || ip_addr_family == AF_INET6)) {
-        throw netio_exception("Invalid IP address family.");
-    }
-
-    // TODO build another nice HL structure wrapper for outbound connections
-    int status = 1;
-
-    do {
-        if (connection_candidates.empty()) {
-            throw netio_exception("Unable to find suitable connection candidate.");
-        }
-
-        socketaddr socket_identifier = connection_candidates.front();
-        connection_candidates.pop_front();
-        auto_fd socket_candidate{socket(socket_identifier.family(), SOCK_STREAM, 0)};
-
-        if (socket_candidate.valid()) {
-            if (connect(socket_candidate.get(), socket_identifier.ptr(), socket_identifier.size()) == 0) {
-                status = 0;
-
-                if (
-                    const auto existing_fd_flags = fcntl(socket_candidate.get(), F_GETFL, 0);
-                    existing_fd_flags == -1 || fcntl(socket_candidate.get(), F_SETFL, existing_fd_flags | O_NONBLOCK) == -1
-                ) {
-                    throw netio_exception("Failed to set socket mode. fcntl resulted in error:" + std::to_string(errno));
-                }
-
-                // Hier bin ich mir nicht sicher, wie ich das am besten mache. Auch mit socketaddr und type cast ist das irgendwie doof.
-                // Das Problem besteht darin, dass erst nach erfolgreichem connect der Port auf dieser Seite bekannt ist.
-                socketaddr sa_local;
-                socklen_t sa_local_len = sizeof(sockaddr_storage);
-
-                if (getsockname(socket_candidate.get(), sa_local.ptr(), &sa_local_len)) {
-                    // Update length field after the internal structure was modified
-                    // TODO: Maybe make this an internal method in socketaddr to update the size
-                    sa_local = sa_local.ptr();
-                    this->own_address = sa_local;
-                }
-                
-                // Store remote connection endpoint (that is prior to redirect)
-                this->peer_address = socket_identifier;
-                return std::forward<auto_fd>(socket_candidate);
-            }
-        }
-
-        // We don't need to worry about closing broken fd as auto_fd handles this for us
-    } while (status == 1);
-    return null_fd{};
-}
-
-// TODO remove and replace with raw socketaddr constructor from factory and implement connect construcor
-tcp_client::tcp_client(
-    const std::string& peer_address_,
-    const std::string& service_or_port,
-    int ip_addr_family
-) :
-    connection_client{get_connection(peer_address_, service_or_port, ip_addr_family), this->get_peer_address()},
-    destructor_cb(nullptr)
-{}
-
-tcp_client::tcp_client(
-    const std::string &peer_address_,
-    const std::string &service_or_port
-) :
-    tcp_client(peer_address_, service_or_port, AF_UNSPEC)
-{}
-
-tcp_client::tcp_client(
-    const std::string &peer_address_,
-    const uint16_t port_
-) :
-    tcp_client(peer_address_, std::to_string(port_))
-{}*/
-
 tcp_client::~tcp_client() {}
 
 ssize_t tcp_client::push_write_queue(::ev::io& w, iorecord& buffer) {
@@ -131,6 +48,31 @@ inline uint16_t tcp_client::get_port() {
     return optional_port.value();
 }
 
+inline std::string get_recv_error() {
+    switch (errno) {
+    case EBADF:
+        return "The argument sockfd is an invalid file descriptor.";
+    case ECONNREFUSED:
+        return "A remote host refused to allow the network connection.";
+    case EFAULT:
+        return "The receive buffer pointer(s) point outside the process's address space.";
+    case EINTR:
+        return "The receive was interrupted by delivery of a signal before any data was available.";
+    case EINVAL:
+        return "Invalid argument passed.";
+    case ENOMEM:
+        return "Could not allocate memory for recvmsg().";
+    case ENOTCONN:
+        return "The  socket  is  associated  with a connection-oriented protocol and has not been connected.";
+    case ENOTSOCK:
+        return "The file descriptor sockfd does not refer to a socket.";
+    case 104:
+        return "Connection Reset by peer (Linux bug)";
+    default:
+        return "Error Code not captured: " + std::to_string(errno);
+    }
+}
+
 void tcp_client::read_from_socket(::ev::io& w) {
     // notify incomming_data_cb
     uint8_t buffer[1024];
@@ -138,7 +80,12 @@ void tcp_client::read_from_socket(::ev::io& w) {
     ssize_t n_read_bytes = recv(w.fd, buffer, sizeof(buffer), 0);
 
     if (n_read_bytes < 0) {
-        throw netio_exception("Failed to read from network socket in TCP client.");
+        if (errno == ECONNRESET) {
+            this->stop_server();
+            return;
+        } else if (errno != EAGAIN) {
+            throw netio_exception("Failed to read from network socket in TCP client. " + get_recv_error());
+        }
     }
 
     if (n_read_bytes == 0) {

src/net/tcp_server_socket.cpp

@@ -30,46 +30,50 @@
 
 
 namespace rmrf::net {
-    
-    auto_fd create_tcp_server_socket(const socketaddr& socket_identifier) {
-        auto_fd socket_fd{socket(socket_identifier.family(), SOCK_STREAM, 0)};
-        
-        if (!socket_fd.valid()) {
-            // TODO implement propper error handling
-            throw netio_exception("Failed to create socket fd.");
-        }
-        
-        if (auto error = bind(socket_fd.get(), socket_identifier.ptr(), socket_identifier.size()); error != 0) {
-            std::string msg = "Failed to bind to all addresses (FIXME). Errorcode: " + std::to_string(error);
-
-            if (socket_identifier.family() == AF_INET6) {
-                sockaddr_in* inptr = (sockaddr_in*) socket_identifier.ptr();
-                const auto port = ntohs(inptr->sin_port);
-
-                if (port < 1024) {
-                    msg += "\nYou tried to bind to a port smaller than 1024. Are you root?";
-                }
-            } else if (socket_identifier.family() == AF_INET) {
-                sockaddr_in6* inptr = (sockaddr_in6*) socket_identifier.ptr();
-                const auto port = ntohs(inptr->sin6_port);
-
-                if (port < 1024) {
-                    msg += "\nYou tried to bind to a port smaller than 1024. Are you root?";
-                }
+
+static auto_fd create_tcp_server_socket(const socketaddr& socket_identifier) {
+    if (auto f = socket_identifier.family(); f != AF_INET6 && f != AF_INET) {
+        throw netio_exception("For now, TCP is only supported over IP(v6).");
+    }
+
+    auto_fd socket_fd{socket(socket_identifier.family(), SOCK_STREAM, 0)};
+
+    if (!socket_fd.valid()) {
+        // TODO implement propper error handling
+        throw netio_exception("Failed to create socket fd.");
+    }
+
+    if (auto error = bind(socket_fd.get(), socket_identifier.ptr(), socket_identifier.size()); error != 0) {
+        std::string msg = "Failed to bind to all addresses (FIXME). Errorcode: " + std::to_string(error);
+
+        if (socket_identifier.family() == AF_INET6) {
+            sockaddr_in* inptr = (sockaddr_in*) socket_identifier.ptr();
+            const auto port = ntohs(inptr->sin_port);
+
+            if (port < 1024) {
+                msg += "\nYou tried to bind to a port smaller than 1024. Are you root?";
             }
+        } else if (socket_identifier.family() == AF_INET) {
+            sockaddr_in6* inptr = (sockaddr_in6*) socket_identifier.ptr();
+            const auto port = ntohs(inptr->sin6_port);
 
-            throw netio_exception(msg);
-        }
-        
-        make_socket_nonblocking(socket_fd);
-        
-        if (listen(socket_fd.get(), 5) == -1) {
-            throw netio_exception("Failed to enable listening mode for raw socket");
+            if (port < 1024) {
+                msg += "\nYou tried to bind to a port smaller than 1024. Are you root?";
+            }
         }
-        
-        return socket_fd;
+
+        throw netio_exception(msg);
+    }
+
+    make_socket_nonblocking(socket_fd);
+
+    if (listen(socket_fd.get(), 128) == -1) {
+        throw netio_exception("Failed to enable listening mode for raw socket");
     }
 
+    return socket_fd;
+}
+
 tcp_server_socket::tcp_server_socket(
     const socketaddr& socket_identifier,
     async_server_socket::accept_handler_type client_listener
@@ -111,7 +115,7 @@ std::shared_ptr<connection_client> tcp_server_socket::await_raw_socket_incomming
     if (client_fd_raw < 0) {
         throw netio_exception("Unable to bind incoming client");
     }
-    
+
     auto client_socket = auto_fd(client_fd_raw);
     make_socket_nonblocking(client_socket);
 
@@ -122,7 +126,7 @@ std::shared_ptr<connection_client> tcp_server_socket::await_raw_socket_incomming
         setsockopt(client_socket.get(), IPPROTO_TCP, TCP_QUICKACK, &one, sizeof(one));
 #endif
     }
-    
+
     return std::make_shared<tcp_client>(
         this->get_locked_destructor_callback(),
         std::move(client_socket),

src/net/unix_socket_server.cpp

+#include "net/unix_socket_server.hpp"
+
+#include <filesystem>
+#include <sstream>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+
+#include "net/async_fd.hpp"
+#include "net/netio_exception.hpp"
+#include "net/socket_utils.hpp"
+#include "net/tcp_client.hpp"
+
+
+namespace rmrf::net {
+
+static std::string get_unix_socket_path(const socketaddr& addr) {
+    if (addr.family() != AF_UNIX) {
+        return {};
+    }
+
+    return std::string(((sockaddr_un*) addr.ptr())->sun_path);
+}
+
+static auto_fd construct_server_fd(const socketaddr& addr) {
+    if (addr.family() != AF_UNIX) {
+        throw netio_exception("Expected a UNIX socket file path.");
+    }
+
+    // man 7 unix suggests the ussage of SOCK_SEQPACKET, but we'd loose the ability to distinguish multiple clients if we do so
+    auto_fd socket_fd{socket(addr.family(), SOCK_STREAM, 0)};
+
+    if (!socket_fd.valid()) {
+        throw netio_exception("Failed to create UNIX socket. Do you have the permissions to do this?");
+    }
+
+    if (auto error = bind(socket_fd.get(), addr.ptr(), addr.size()); error != 0) {
+        std::stringstream ss;
+        ss << "Failed to bind to socket " + addr.str() << ".";
+        const auto p = std::filesystem::path(get_unix_socket_path(addr));
+
+        if (std::filesystem::exists(p)) {
+            ss << " Reason: The file already exists.";
+
+            if (std::filesystem::is_socket(p)) {
+                ss << " It is also a socket. Is the application already running?";
+            }
+        } else {
+            ss << " Is there buffer space avaiable and do you have the permission to create a socket there?";
+        }
+
+        throw netio_exception(ss.str());
+    }
+
+    make_socket_nonblocking(socket_fd);
+
+    if (listen(socket_fd.get(), 5) == -1) {
+        // We already created the socket and close won't remove the file thus we need to unlink it.
+        unlink(get_unix_socket_path(addr).c_str());
+        throw netio_exception("Failed to enable listening mode for raw socket");
+    }
+
+    return socket_fd;
+}
+
+unix_socket_server::unix_socket_server(
+    const socketaddr& socket_identifier,
+    async_server_socket::accept_handler_type client_listener_
+) : async_server_socket{construct_server_fd(socket_identifier)}, socket_path{get_unix_socket_path(socket_identifier)} {
+    this->set_accept_handler(client_listener_);
+}
+
+unix_socket_server::~unix_socket_server() {
+    if (this->socket_path.length() > 0) {
+        // We're ignoring potential errors as there's nothing we can do about it anyway.
+        unlink(this->socket_path.c_str());
+    }
+}
+
+std::shared_ptr<connection_client> unix_socket_server::await_raw_socket_incomming(const auto_fd& server_socket) {
+    auto client_socket = auto_fd{accept(server_socket.get(), nullptr, nullptr)};
+
+    if (!client_socket.valid()) {
+        throw netio_exception("Failed to accept incomming client to unix socket.");
+    }
+
+    make_socket_nonblocking(client_socket);
+
+    const socketaddr own_address{}, peer_address{};
+
+    return std::make_shared<tcp_client>(
+        this->get_locked_destructor_callback(),
+        std::move(client_socket),
+        own_address,
+        peer_address);
+}
+
+}

src/net/unix_socket_server.hpp

+#pragma once
+
+#include <string>
+
+#include "net/async_fd.hpp"
+#include "net/async_server.hpp"
+#include "net/socketaddress.hpp"
+
+namespace rmrf::net {
+
+/**
+ * @class unix_socket_server
+ * @author doralitze
+ * @date 12/03/23
+ * @file unix_socket_server.hpp
+ * @brief A unix file socket server
+ */
+class unix_socket_server : public async_server_socket
+{
+private:
+    std::string socket_path;
+
+public:
+    unix_socket_server(const socketaddr& socket_identifier, async_server_socket::accept_handler_type client_listener_);
+    virtual ~unix_socket_server();
+
+public:
+    virtual std::shared_ptr<connection_client> await_raw_socket_incomming(const auto_fd& socket);
+};
+
+}

test/address_tests.cpp

@@ -46,6 +46,11 @@ BOOST_AUTO_TEST_CASE(Socketaddr_IPv6_Construction_Test) {
     BOOST_CHECK_EQUAL(sa.str(), "SocketAddress: IPv6 [::]:80");
 }
 
+BOOST_AUTO_TEST_CASE(Socketaddr_IPv6_Any_Interface_Construction_Test) {
+    const auto sa = get_first_general_socketaddr("[::]", "80");
+    BOOST_CHECK_EQUAL(sa.str(), "SocketAddress: IPv6 [::]:80");
+}
+
 BOOST_AUTO_TEST_CASE(Socketaddr_IPv6_Localhost_Construction_Test) {
     sockaddr_in6 addr_ip6;
     addr_ip6.sin6_family = AF_INET6;
@@ -62,3 +67,8 @@ BOOST_AUTO_TEST_CASE(Socketaddr_comparison) {
     BOOST_CHECK_NE(get_first_general_socketaddr("[::1]", "443"), get_first_general_socketaddr("::1", "80"));
     BOOST_CHECK_EQUAL(get_first_general_socketaddr("[::1]", "443"), get_first_general_socketaddr("::1", "443"));
 }
+
+BOOST_AUTO_TEST_CASE(Unix_socket_construction_test) {
+    const auto sa = get_first_general_socketaddr("/tmp/9Lq7BNBnBycd6nxy.socket", "", socket_t::UNIX);
+    BOOST_CHECK_EQUAL(sa.str(), "SocketAddress: FileSocket /tmp/9Lq7BNBnBycd6nxy.socket");
+}

test/loopback_connection_client.hpp

@@ -31,7 +31,7 @@ public:
         data_archive{},
         echo_data_transfer(echo_data)
     {
-        // Does nothing special
+        this->server_active = true;
     }
 
     /**

test/socket_test.cpp

@@ -15,6 +15,7 @@
 #include "net/socketaddress.hpp"
 #include "net/sock_address_factory.hpp"
 #include "net/tcp_server_socket.hpp"
+#include "net/unix_socket_server.hpp"
 
 #include "lib/ev/ev.hpp"
 #include "mumta/evloop.hpp"
@@ -27,6 +28,7 @@ const std::string udp_test_string = "TEST UDP PACKET";
 
 volatile bool tcp_called = false;
 volatile bool udp_called = false;
+volatile bool unix_called = false;
 
 int udp_source_family;
 
@@ -118,6 +120,38 @@ void run_tcp_test(const socketaddr& interface_addr) {
     server.reset();
 }
 
+void run_unix_test() {
+    using namespace std::chrono_literals;
+
+    const socketaddr socket_name = get_first_general_socketaddr("/tmp/9Lq7BNBnBycd6nxy.socket", "", socket_t::UNIX);
+
+    auto server = std::make_shared<unix_socket_server>(socket_name,
+        [](std::shared_ptr<async_server_socket> s, std::shared_ptr<connection_client> c) {
+            BOOST_REQUIRE(s);
+            BOOST_REQUIRE(c);
+            c->set_incomming_data_callback(
+                [c](const iorecord& data) {
+                    c->write_data(data);
+                });
+        });
+
+    auto client = connect(socket_name);
+    client->set_incomming_data_callback(
+        [](const iorecord& data) {
+            BOOST_CHECK_EQUAL(data.str(), "Moin, von UNIX");
+            unix_called = true;
+        });
+
+    const std::string moin_string("Moin, von UNIX");
+    client->write_data(iorecord(moin_string.c_str(), moin_string.length()));
+
+    std::this_thread::yield();
+    std::this_thread::sleep_for(100ms);
+
+    client.reset();
+    server.reset();
+}
+
 BOOST_AUTO_TEST_CASE(Netio_Socket_TCP) {
     using namespace std::chrono_literals;
 
@@ -149,3 +183,18 @@ BOOST_AUTO_TEST_CASE(Netio_Socket_UDP) {
 
     BOOST_CHECK(udp_called);
 }
+
+BOOST_AUTO_TEST_CASE(Netio_Socket_UNIX) {
+    using namespace std::chrono_literals;
+
+    std::thread ev_thread(ev_thread_callable);
+
+    BOOST_CHECK_NO_THROW(run_unix_test()); // TODO put in own test while keeping same ev loop setup
+
+    // Sleep one second without using ev timer
+    std::this_thread::sleep_for(500ms);
+
+    ev_thread.join();
+
+    BOOST_CHECK(unix_called);
+}