Package Socket:

- fix tcp,udp,unix socket
- add socket unixgram for session less unix socket
- optmize process & code
- add some standalone test for server / client (add example server config for
  rsyslog)

Package Network/Protocol:
- add unixgram protocol

Package Errors:
- fix bug in loop to prevent circular include

socket/server/unixgram/model.go

@@ -0,0 +1,176 @@
+//go:build linux
+// +build linux
+
+/*
+ * MIT License
+ *
+ * Copyright (c) 2022 Nicolas JUHEL
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ *
+ */
+
+package unixgram
+
+import (
+	"fmt"
+	"net"
+	"os"
+	"sync/atomic"
+
+	libptc "github.com/nabbar/golib/network/protocol"
+
+	libtls "github.com/nabbar/golib/certificates"
+	libsck "github.com/nabbar/golib/socket"
+)
+
+var (
+	closedChanStruct chan struct{}
+)
+
+func init() {
+	closedChanStruct = make(chan struct{})
+	close(closedChanStruct)
+}
+
+type srv struct {
+	l net.Listener
+
+	h *atomic.Value // handler
+	c *atomic.Value // chan []byte
+	s *atomic.Value // chan struct{}
+
+	fe *atomic.Value // function error
+	fi *atomic.Value // function info
+	fs *atomic.Value // function info server
+
+	sr *atomic.Int32 // read buffer size
+	sf *atomic.Value // file unix socket
+	sp *atomic.Int64 // file unix perm
+	sg *atomic.Int32 // file unix group perm
+}
+
+func (o *srv) Done() <-chan struct{} {
+	s := o.s.Load()
+	if s != nil {
+		return s.(chan struct{})
+	}
+
+	return closedChanStruct
+}
+
+func (o *srv) Shutdown() {
+	if o == nil {
+		return
+	}
+
+	s := o.s.Load()
+	if s != nil {
+		o.s.Store(nil)
+	}
+}
+
+func (o *srv) SetTLS(enable bool, config libtls.TLSConfig) error {
+	return nil
+}
+
+func (o *srv) RegisterFuncError(f libsck.FuncError) {
+	if o == nil {
+		return
+	}
+
+	o.fe.Store(f)
+}
+
+func (o *srv) RegisterFuncInfo(f libsck.FuncInfo) {
+	if o == nil {
+		return
+	}
+
+	o.fi.Store(f)
+}
+
+func (o *srv) RegisterFuncInfoServer(f libsck.FuncInfoSrv) {
+	if o == nil {
+		return
+	}
+
+	o.fs.Store(f)
+}
+
+func (o *srv) RegisterSocket(unixFile string, perm os.FileMode, gid int32) error {
+	if _, err := net.ResolveUnixAddr(libptc.NetworkUnixGram.Code(), unixFile); err != nil {
+		return err
+	} else if gid > maxGID {
+		return ErrInvalidGroup
+	}
+
+	o.sf.Store(unixFile)
+	o.sp.Store(int64(perm))
+	o.sg.Store(gid)
+
+	return nil
+}
+
+func (o *srv) fctError(e error) {
+	if o == nil {
+		return
+	}
+
+	v := o.fe.Load()
+	if v != nil {
+		v.(libsck.FuncError)(e)
+	}
+}
+
+func (o *srv) fctInfo(local, remote net.Addr, state libsck.ConnState) {
+	if o == nil {
+		return
+	}
+
+	v := o.fi.Load()
+	if v != nil {
+		v.(libsck.FuncInfo)(local, remote, state)
+	}
+}
+
+func (o *srv) fctInfoSrv(msg string, args ...interface{}) {
+	if o == nil {
+		return
+	}
+
+	v := o.fs.Load()
+	if v != nil {
+		v.(libsck.FuncInfoSrv)(fmt.Sprintf(msg, args...))
+	}
+}
+
+func (o *srv) handler() libsck.Handler {
+	if o == nil {
+		return nil
+	}
+
+	v := o.h.Load()
+	if v != nil {
+		return v.(libsck.Handler)
+	}
+
+	return nil
+}