huatuo/core/events/dropwatch.go

265 lines
7.4 KiB
Go

// Copyright 2025 The HuaTuo Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package events
import (
"context"
"fmt"
"net"
"strings"
"time"
"huatuo-bamai/internal/bpf"
"huatuo-bamai/internal/conf"
"huatuo-bamai/internal/log"
"huatuo-bamai/internal/storage"
"huatuo-bamai/internal/utils/bpfutil"
"huatuo-bamai/internal/utils/netutil"
"huatuo-bamai/internal/utils/symbolutil"
"huatuo-bamai/pkg/tracing"
)
const (
tracerName = "dropwatch"
logPrefix = tracerName + ": "
// type
typeTCPCommonDrop = 1
typeTCPSynFlood = 2
typeTCPListenOverflowHandshake1 = 3
typeTCPListenOverflowHandshake3 = 4
)
// from include/net/tcp_states.h
var tcpstateMap = []string{
"<nil>", // 0
"ESTABLISHED",
"SYN_SENT",
"SYN_RECV",
"FIN_WAIT1",
"FIN_WAIT2",
"TIME_WAIT",
"CLOSE",
"CLOSE_WAIT",
"LAST_ACK",
"LISTEN",
"CLOSING",
"NEW_SYN_RECV",
}
var typeMap = map[uint8]string{
typeTCPCommonDrop: "common_drop",
typeTCPSynFlood: "syn_flood",
typeTCPListenOverflowHandshake1: "listen_overflow_handshake1",
typeTCPListenOverflowHandshake3: "listen_overflow_handshake3",
}
type perfEventT struct {
TgidPid uint64 `json:"tgid_pid"`
Saddr uint32 `json:"saddr"`
Daddr uint32 `json:"daddr"`
Sport uint16 `json:"sport"`
Dport uint16 `json:"dport"`
Seq uint32 `json:"seq"`
AckSeq uint32 `json:"ack_seq"`
QueueMapping uint32 `json:"queue_mapping"`
PktLen uint64 `json:"pkt_len"`
StackSize int64 `json:"stack_size"`
Stack [symbolutil.KsymbolStackMaxDepth]uint64 `json:"stack"`
SkMaxAckBacklog uint32 `json:"sk_max_ack_backlog"`
State uint8 `json:"state"`
Type uint8 `json:"type"`
Comm [bpfutil.TaskCommLen]byte `json:"comm"`
}
type DropWatchTracingData struct {
Type string `json:"type"`
Comm string `json:"comm"`
Pid uint64 `json:"pid"`
Saddr string `json:"saddr"`
Daddr string `json:"daddr"`
Sport uint16 `json:"sport"`
Dport uint16 `json:"dport"`
SrcHostname string `json:"src_hostname"`
DestHostname string `json:"dest_hostname"`
MaxAckBacklog uint32 `json:"max_ack_backlog"`
Seq uint32 `json:"seq"`
AckSeq uint32 `json:"ack_seq"`
QueueMapping uint32 `json:"queue_mapping"`
PktLen uint64 `json:"pkt_len"`
State string `json:"state"`
Stack string `json:"stack"`
}
type dropWatchTracing struct{}
//go:generate $BPF_COMPILE $BPF_INCLUDE -s $BPF_DIR/dropwatch.c -o $BPF_DIR/dropwatch.o
func init() {
tracing.RegisterEventTracing(tracerName, newDropWatch)
}
func newDropWatch() (*tracing.EventTracingAttr, error) {
return &tracing.EventTracingAttr{
TracingData: &dropWatchTracing{},
Internal: 10,
Flag: tracing.FlagTracing,
}, nil
}
// Start starts the tracer.
func (c *dropWatchTracing) Start(ctx context.Context) error {
log.Info(logPrefix + "tracer will be starting.")
b, err := bpf.LoadBpf(bpfutil.ThisBpfOBJ(), nil)
if err != nil {
return fmt.Errorf(logPrefix+"failed to load bpf: %w", err)
}
defer b.Close()
childCtx, cancel := context.WithCancel(ctx)
defer cancel()
// attach
reader, err := b.AttachAndEventPipe(childCtx, "perf_events", 8192)
if err != nil {
return fmt.Errorf(logPrefix+"failed to attach and event pipe: %w", err)
}
defer reader.Close()
// breaker
b.WaitDetachByBreaker(childCtx, cancel)
log.Info(logPrefix + "tracer is waitting for event.")
for {
select {
case <-childCtx.Done():
log.Info(logPrefix + "tracer is stopped.")
return nil
default:
var event perfEventT
if err := reader.ReadInto(&event); err != nil {
return fmt.Errorf(logPrefix+"failed to read from perf: %w", err)
}
// format
tracerTime := time.Now()
tracerData := c.formatEvent(&event)
// ignore
if c.ignore(tracerData) {
log.Debugf(logPrefix+"ignore dropwatch data: %v", tracerData)
continue
}
// save storage
storage.Save(tracerName, "", tracerTime, tracerData)
}
}
}
func (c *dropWatchTracing) formatEvent(event *perfEventT) *DropWatchTracingData {
// hostname
saddr := netutil.InetNtop(event.Saddr).String()
daddr := netutil.InetNtop(event.Daddr).String()
srcHostname := "<nil>"
destHostname := "<nil>"
h, err := net.LookupAddr(saddr)
if err == nil && len(h) > 0 {
srcHostname = h[0]
}
h, err = net.LookupAddr(daddr)
if err == nil && len(h) > 0 {
destHostname = h[0]
}
// stack
stacks := strings.Join(symbolutil.DumpKernelBackTrace(event.Stack[:], symbolutil.KsymbolStackMaxDepth).BackTrace, "\n")
// tracer data
data := &DropWatchTracingData{
Type: typeMap[event.Type],
Comm: strings.TrimRight(string(event.Comm[:]), "\x00"),
Pid: event.TgidPid >> 32,
Saddr: saddr,
Daddr: daddr,
Sport: netutil.InetNtohs(event.Sport),
Dport: netutil.InetNtohs(event.Dport),
SrcHostname: srcHostname,
DestHostname: destHostname,
Seq: netutil.InetNtohl(event.Seq),
AckSeq: netutil.InetNtohl(event.AckSeq),
QueueMapping: event.QueueMapping,
PktLen: event.PktLen,
State: tcpstateMap[event.State],
Stack: stacks,
MaxAckBacklog: event.SkMaxAckBacklog,
}
log.Debugf(logPrefix+"tracing data: %v", data)
return data
}
func (c *dropWatchTracing) ignore(data *DropWatchTracingData) bool {
stack := strings.Split(data.Stack, "\n")
// state: CLOSE_WAIT
// stack:
// 1. kfree_skb/ffffffff963047b0
// 2. kfree_skb/ffffffff963047b0
// 3. skb_rbtree_purge/ffffffff963089e0
// 4. tcp_fin/ffffffff963ac200
// 5. ...
if data.State == "CLOSE_WAIT" {
if len(stack) >= 3 && strings.HasPrefix(stack[2], "skb_rbtree_purge/") {
return true
}
}
// stack:
// 1. kfree_skb/ffffffff96d127b0
// 2. kfree_skb/ffffffff96d127b0
// 3. neigh_invalidate/ffffffff96d388b0
// 4. neigh_timer_handler/ffffffff96d3a870
// 5. ...
if conf.Get().Tracing.Dropwatch.IgnoreNeighInvalidate {
if len(stack) >= 3 && strings.HasPrefix(stack[2], "neigh_invalidate/") {
return true
}
}
// stack:
// 1. kfree_skb/ffffffff82283d10
// 2. kfree_skb/ffffffff82283d10
// 3. bnxt_tx_int/ffffffffc05c6f20
// 4. __bnxt_poll_work_done/ffffffffc05c50c0
// 5. ...
// stack:
// 1. kfree_skb/ffffffffaba83d10
// 2. kfree_skb/ffffffffaba83d10
// 3. __bnxt_tx_int/ffffffffc045df90
// 4. bnxt_tx_int/ffffffffc045e250
// 5. ...
if len(stack) >= 3 &&
(strings.HasPrefix(stack[2], "bnxt_tx_int/") || strings.HasPrefix(stack[2], "__bnxt_tx_int/")) {
return true
}
// default: false
return false
}