fix: same TCP connection appears twice

```
TCP, TCP6, UDP, and UDP6 are dynamically changing,
and when we read these files, we should read them all at once.
there will be data consistency issues if using line by lin reading

fix: #576
```

Signed-off-by: weidongkl <[email protected]>

net_ip_socket.go

@@ -14,10 +14,8 @@
 package procfs
 
 import (
-	"bufio"
 	"encoding/hex"
 	"fmt"
-	"io"
 	"net"
 	"os"
 	"strconv"
@@ -74,49 +72,50 @@ type (
 )
 
 func newNetIPSocket(file string) (NetIPSocket, error) {
-	f, err := os.Open(file)
+	var netIPSocket NetIPSocket
+	isUDP := strings.Contains(file, "udp")
+	content, err := os.ReadFile(file)
 	if err != nil {
 		return nil, err
 	}
-	defer f.Close()
-
-	var netIPSocket NetIPSocket
-	isUDP := strings.Contains(file, "udp")
+	lines := strings.Split(string(content), "\n")
+	if len(lines) < 1 {
+		return nil, ErrFileParse
+	}
 
-	lr := io.LimitReader(f, readLimit)
-	s := bufio.NewScanner(lr)
-	s.Scan() // skip first line with headers
-	for s.Scan() {
-		fields := strings.Fields(s.Text())
+	for _, line := range lines[1:] {
+		fields := strings.Fields(line)
+		if len(fields) == 0 {
+			continue
+		}
 		line, err := parseNetIPSocketLine(fields, isUDP)
 		if err != nil {
 			return nil, err
 		}
 		netIPSocket = append(netIPSocket, line)
 	}
-	if err := s.Err(); err != nil {
-		return nil, err
-	}
 	return netIPSocket, nil
 }
 
 // newNetIPSocketSummary creates a new NetIPSocket{,6} from the contents of the given file.
 func newNetIPSocketSummary(file string) (*NetIPSocketSummary, error) {
-	f, err := os.Open(file)
-	if err != nil {
-		return nil, err
-	}
-	defer f.Close()
-
 	var netIPSocketSummary NetIPSocketSummary
 	var udpPacketDrops uint64
 	isUDP := strings.Contains(file, "udp")
+	content, err := os.ReadFile(file)
+	if err != nil {
+		return nil, err
+	}
+	lines := strings.Split(string(content), "\n")
+	if len(lines) < 1 {
+		return nil, ErrFileParse
+	}
 
-	lr := io.LimitReader(f, readLimit)
-	s := bufio.NewScanner(lr)
-	s.Scan() // skip first line with headers
-	for s.Scan() {
-		fields := strings.Fields(s.Text())
+	for _, line := range lines[1:] {
+		fields := strings.Fields(line)
+		if len(fields) == 0 {
+			continue
+		}
 		line, err := parseNetIPSocketLine(fields, isUDP)
 		if err != nil {
 			return nil, err
@@ -129,9 +128,6 @@ func newNetIPSocketSummary(file string) (*NetIPSocketSummary, error) {
 			netIPSocketSummary.Drops = &udpPacketDrops
 		}
 	}
-	if err := s.Err(); err != nil {
-		return nil, err
-	}
 	return &netIPSocketSummary, nil
 }