Report persistent connections in states other than ESTABLISHED

This aligns the `/proc` connection tracking (persistent connections) with
conntrack (short-lived connections).

probe/endpoint/procspy/procnet.go

@@ -9,17 +9,15 @@ import (
 type ProcNet struct {
 	b                       []byte
 	c                       Connection
-	wantedState             uint
 	bytesLocal, bytesRemote [16]byte
 	seen                    map[uint64]struct{}
 }
 
 // NewProcNet gives a new ProcNet parser.
-func NewProcNet(b []byte, wantedState uint) *ProcNet {
+func NewProcNet(b []byte) *ProcNet {
 	return &ProcNet{
 		b:           b,
 		c:           Connection{},
-		wantedState: wantedState,
 		seen:        map[uint64]struct{}{},
 	}
 }
@@ -40,16 +38,12 @@ again:
 	}
 
 	var (
-		local, remote, state, inode []byte
+		local, remote, inode []byte
 	)
 	_, b = nextField(b) // 'sl' column
 	local, b = nextField(b)
 	remote, b = nextField(b)
-	state, b = nextField(b)
-	if parseHex(state) != p.wantedState {
-		p.b = nextLine(b)
-		goto again
-	}
+	_, b = nextField(b) // 'st' column
 	_, b = nextField(b) // 'tx_queue' column
 	_, b = nextField(b) // 'rx_queue' column
 	_, b = nextField(b) // 'tr' column

probe/endpoint/procspy/spy.go

@@ -7,10 +7,6 @@ import (
 	"net"
 )
 
-const (
-	tcpEstablished = 1 // according to /include/net/tcp_states.h
-)
-
 // Connection is a (TCP) connection. The Proc struct might not be filled in.
 type Connection struct {
 	Transport     string

probe/endpoint/procspy/spy_linux.go

@@ -61,7 +61,7 @@ func (s *linuxScanner) Connections(processes bool) (ConnIter, error) {
 	}
 
 	return &pnConnIter{
-		pn:    NewProcNet(buf.Bytes(), tcpEstablished),
+		pn:    NewProcNet(buf.Bytes()),
 		buf:   buf,
 		procs: procs,
 	}, nil