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Revert "fix: same TCP connection appears twice (#631)" (#633)
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This reverts commit 987bedc.
SuperQ authored Apr 17, 2024

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This commit was created on GitHub.com and signed with GitHub’s verified signature.
1 parent 987bedc commit 6bec248
Showing 1 changed file with 39 additions and 25 deletions.
64 changes: 39 additions & 25 deletions net_ip_socket.go
Original file line number Diff line number Diff line change
@@ -14,14 +14,26 @@
package procfs

import (
"bufio"
"encoding/hex"
"fmt"
"io"
"net"
"os"
"strconv"
"strings"
)

const (
// readLimit is used by io.LimitReader while reading the content of the
// /proc/net/udp{,6} files. The number of lines inside such a file is dynamic
// as each line represents a single used socket.
// In theory, the number of available sockets is 65535 (2^16 - 1) per IP.
// With e.g. 150 Byte per line and the maximum number of 65535,
// the reader needs to handle 150 Byte * 65535 =~ 10 MB for a single IP.
readLimit = 4294967296 // Byte -> 4 GiB
)

// This contains generic data structures for both udp and tcp sockets.
type (
// NetIPSocket represents the contents of /proc/net/{t,u}dp{,6} file without the header.
@@ -62,50 +74,49 @@ type (
)

func newNetIPSocket(file string) (NetIPSocket, error) {
var netIPSocket NetIPSocket
isUDP := strings.Contains(file, "udp")
content, err := os.ReadFile(file)
f, err := os.Open(file)
if err != nil {
return nil, err
}
lines := strings.Split(string(content), "\n")
if len(lines) < 1 {
return nil, ErrFileParse
}
defer f.Close()

for _, line := range lines[1:] {
fields := strings.Fields(line)
if len(fields) == 0 {
continue
}
var netIPSocket NetIPSocket
isUDP := strings.Contains(file, "udp")

lr := io.LimitReader(f, readLimit)
s := bufio.NewScanner(lr)
s.Scan() // skip first line with headers
for s.Scan() {
fields := strings.Fields(s.Text())
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) {
var netIPSocketSummary NetIPSocketSummary
var udpPacketDrops uint64
isUDP := strings.Contains(file, "udp")
content, err := os.ReadFile(file)
f, err := os.Open(file)
if err != nil {
return nil, err
}
lines := strings.Split(string(content), "\n")
if len(lines) < 1 {
return nil, ErrFileParse
}
defer f.Close()

for _, line := range lines[1:] {
fields := strings.Fields(line)
if len(fields) == 0 {
continue
}
var netIPSocketSummary NetIPSocketSummary
var udpPacketDrops uint64
isUDP := strings.Contains(file, "udp")

lr := io.LimitReader(f, readLimit)
s := bufio.NewScanner(lr)
s.Scan() // skip first line with headers
for s.Scan() {
fields := strings.Fields(s.Text())
line, err := parseNetIPSocketLine(fields, isUDP)
if err != nil {
return nil, err
@@ -118,6 +129,9 @@ func newNetIPSocketSummary(file string) (*NetIPSocketSummary, error) {
netIPSocketSummary.Drops = &udpPacketDrops
}
}
if err := s.Err(); err != nil {
return nil, err
}
return &netIPSocketSummary, nil
}

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