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Implement UDP socket diagnostics
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Signed-off-by: Sven Rebhan <srebhan@influxdata.com>
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@srebhan
srebhan committed Nov 30, 2023
1 parent 0ced838 commit 804e141
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Showing 4 changed files with 149 additions and 25 deletions.
5 changes: 5 additions & 0 deletions inet_diag.go
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Original file line number Diff line number Diff line change
Expand Up @@ -29,3 +29,8 @@ type InetDiagTCPInfoResp struct {
TCPInfo *TCPInfo
TCPBBRInfo *TCPBBRInfo
}

type InetDiagUDPInfoResp struct {
InetDiagMsg *Socket
Memory *MemInfo
}
146 changes: 121 additions & 25 deletions socket_linux.go
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Original file line number Diff line number Diff line change
Expand Up @@ -174,8 +174,18 @@ func SocketGet(local, remote net.Addr) (*Socket, error) {

// SocketDiagTCPInfo requests INET_DIAG_INFO for TCP protocol for specified family type and return with extension TCP info.
func SocketDiagTCPInfo(family uint8) ([]*InetDiagTCPInfoResp, error) {
// Construct the request
req := nl.NewNetlinkRequest(nl.SOCK_DIAG_BY_FAMILY, unix.NLM_F_DUMP)
req.AddData(&socketRequest{
Family: family,
Protocol: unix.IPPROTO_TCP,
Ext: (1 << (INET_DIAG_VEGASINFO - 1)) | (1 << (INET_DIAG_INFO - 1)),
States: uint32(0xfff), // all states
})

// Do the query and parse the result
var result []*InetDiagTCPInfoResp
err := socketDiagTCPExecutor(family, func(m syscall.NetlinkMessage) error {
err := socketDiagExecutor(req, func(m syscall.NetlinkMessage) error {
sockInfo := &Socket{}
if err := sockInfo.deserialize(m.Data); err != nil {
return err
Expand All @@ -201,8 +211,18 @@ func SocketDiagTCPInfo(family uint8) ([]*InetDiagTCPInfoResp, error) {

// SocketDiagTCP requests INET_DIAG_INFO for TCP protocol for specified family type and return related socket.
func SocketDiagTCP(family uint8) ([]*Socket, error) {
// Construct the request
req := nl.NewNetlinkRequest(nl.SOCK_DIAG_BY_FAMILY, unix.NLM_F_DUMP)
req.AddData(&socketRequest{
Family: family,
Protocol: unix.IPPROTO_TCP,
Ext: (1 << (INET_DIAG_VEGASINFO - 1)) | (1 << (INET_DIAG_INFO - 1)),
States: uint32(0xfff), // all states
})

// Do the query and parse the result
var result []*Socket
err := socketDiagTCPExecutor(family, func(m syscall.NetlinkMessage) error {
err := socketDiagExecutor(req, func(m syscall.NetlinkMessage) error {
sockInfo := &Socket{}
if err := sockInfo.deserialize(m.Data); err != nil {
return err
Expand All @@ -216,21 +236,82 @@ func SocketDiagTCP(family uint8) ([]*Socket, error) {
return result, nil
}

// socketDiagTCPExecutor requests INET_DIAG_INFO for TCP protocol for specified family type.
func socketDiagTCPExecutor(family uint8, receiver func(syscall.NetlinkMessage) error) error {
s, err := nl.Subscribe(unix.NETLINK_INET_DIAG)
// SocketDiagUDPInfo requests INET_DIAG_INFO for UDP protocol for specified family type and return with extension info.
func SocketDiagUDPInfo(family uint8) ([]*InetDiagUDPInfoResp, error) {
// Construct the request
var extensions uint8
extensions = 1 << (INET_DIAG_VEGASINFO - 1)
extensions |= 1 << (INET_DIAG_INFO - 1)
extensions |= 1 << (INET_DIAG_MEMINFO - 1)

req := nl.NewNetlinkRequest(nl.SOCK_DIAG_BY_FAMILY, unix.NLM_F_DUMP)
req.AddData(&socketRequest{
Family: family,
Protocol: unix.IPPROTO_UDP,
Ext: extensions,
States: uint32(0xfff), // all states
})

// Do the query and parse the result
var result []*InetDiagUDPInfoResp
err := socketDiagExecutor(req, func(m syscall.NetlinkMessage) error {
sockInfo := &Socket{}
if err := sockInfo.deserialize(m.Data); err != nil {
return err
}
attrs, err := nl.ParseRouteAttr(m.Data[sizeofSocket:])
if err != nil {
return err
}

res, err := attrsToInetDiagUDPInfoResp(attrs, sockInfo)
if err != nil {
return err
}

result = append(result, res)
return nil
})
if err != nil {
return err
return nil, err
}
defer s.Close()
return result, nil
}

// SocketDiagUDP requests INET_DIAG_INFO for UDP protocol for specified family type and return related socket.
func SocketDiagUDP(family uint8) ([]*Socket, error) {
// Construct the request
req := nl.NewNetlinkRequest(nl.SOCK_DIAG_BY_FAMILY, unix.NLM_F_DUMP)
req.AddData(&socketRequest{
Family: family,
Protocol: unix.IPPROTO_TCP,
Protocol: unix.IPPROTO_UDP,
Ext: (1 << (INET_DIAG_VEGASINFO - 1)) | (1 << (INET_DIAG_INFO - 1)),
States: uint32(0xfff), // All TCP states
States: uint32(0xfff), // all states
})

// Do the query and parse the result
var result []*Socket
err := socketDiagExecutor(req, func(m syscall.NetlinkMessage) error {
sockInfo := &Socket{}
if err := sockInfo.deserialize(m.Data); err != nil {
return err
}
result = append(result, sockInfo)
return nil
})
if err != nil {
return nil, err
}
return result, nil
}

// socketDiagExecutor requests diagnoses info from the NETLINK_INET_DIAG socket for the specified request.
func socketDiagExecutor(req *nl.NetlinkRequest, receiver func(syscall.NetlinkMessage) error) error {
s, err := nl.Subscribe(unix.NETLINK_INET_DIAG)
if err != nil {
return err
}
defer s.Close()
s.Send(req)

loop:
Expand All @@ -240,7 +321,7 @@ loop:
return err
}
if from.Pid != nl.PidKernel {
return fmt.Errorf("Wrong sender portid %d, expected %d", from.Pid, nl.PidKernel)
return fmt.Errorf("wrong sender portid %d, expected %d", from.Pid, nl.PidKernel)
}
if len(msgs) == 0 {
return errors.New("no message nor error from netlink")
Expand All @@ -263,29 +344,44 @@ loop:
}

func attrsToInetDiagTCPInfoResp(attrs []syscall.NetlinkRouteAttr, sockInfo *Socket) (*InetDiagTCPInfoResp, error) {
var tcpInfo *TCPInfo
var tcpBBRInfo *TCPBBRInfo
info := &InetDiagTCPInfoResp{
InetDiagMsg: sockInfo,
}
for _, a := range attrs {
if a.Attr.Type == INET_DIAG_INFO {
tcpInfo = &TCPInfo{}
if err := tcpInfo.deserialize(a.Value); err != nil {
switch a.Attr.Type {
case INET_DIAG_INFO:
info.TCPInfo = &TCPInfo{}
if err := info.TCPInfo.deserialize(a.Value); err != nil {
return nil, err
}
continue
case INET_DIAG_BBRINFO:
info.TCPBBRInfo = &TCPBBRInfo{}
if err := info.TCPBBRInfo.deserialize(a.Value); err != nil {
return nil, err
}
// default:
// fmt.Println("unknown TCP attribute type", a.Attr.Type, "with data", a.Value)
}
}

return info, nil
}

if a.Attr.Type == INET_DIAG_BBRINFO {
tcpBBRInfo = &TCPBBRInfo{}
if err := tcpBBRInfo.deserialize(a.Value); err != nil {
func attrsToInetDiagUDPInfoResp(attrs []syscall.NetlinkRouteAttr, sockInfo *Socket) (*InetDiagUDPInfoResp, error) {
info := &InetDiagUDPInfoResp{
InetDiagMsg: sockInfo,
}
for _, a := range attrs {
switch a.Attr.Type {
case INET_DIAG_MEMINFO:
info.Memory = &MemInfo{}
if err := info.Memory.deserialize(a.Value); err != nil {
return nil, err
}
continue
// default:
// fmt.Println("unknown UDP attribute type", a.Attr.Type, "with data", a.Value)
}
}

return &InetDiagTCPInfoResp{
InetDiagMsg: sockInfo,
TCPInfo: tcpInfo,
TCPBBRInfo: tcpBBRInfo,
}, nil
return info, nil
}
8 changes: 8 additions & 0 deletions tcp.go
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Original file line number Diff line number Diff line change
Expand Up @@ -82,3 +82,11 @@ type TCPBBRInfo struct {
BBRPacingGain uint32
BBRCwndGain uint32
}

// According to https://man7.org/linux/man-pages/man7/sock_diag.7.html
type MemInfo struct {
RMem uint32
WMem uint32
FMem uint32
TMem uint32
}
15 changes: 15 additions & 0 deletions tcp_linux.go
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@ import (

const (
tcpBBRInfoLen = 20
memInfoLen = 16
)

func checkDeserErr(err error) error {
Expand Down Expand Up @@ -351,3 +352,17 @@ func (t *TCPBBRInfo) deserialize(b []byte) error {

return nil
}

func (m *MemInfo) deserialize(b []byte) error {
if len(b) != memInfoLen {
return errors.New("Invalid length")
}

rb := bytes.NewBuffer(b)
m.RMem = native.Uint32(rb.Next(4))
m.WMem = native.Uint32(rb.Next(4))
m.FMem = native.Uint32(rb.Next(4))
m.TMem = native.Uint32(rb.Next(4))

return nil
}

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