设计Go语言Ping库：ICMP超时与晚到回复的优雅处理

Request timeout for icmp_seq 2
Request timeout for icmp_seq 3
64 bytes from 80.67.169.18: icmp_seq=2 ttl=58 time=2216.104 ms
64 bytes from 80.67.169.18: icmp_seq=3 ttl=58 time=1216.559 ms

// ...
ipconn.SetReadDeadline(time.Now().Add(time.Second * 1)) // 1 second timeout for each read

resp := make([]byte, 1024)
for {
    readsize, err := ipconn.Read(resp)
    elapsed = time.Now().Sub(start)
    rid, rseq, rcode := parsePingReply(resp)

    if err != nil { // Read timeout or other error
        response <- Response{Delay: 0, Error: err, Destination: raddr.IP.String(), Seq: seq, Writesize: writesize, Readsize: readsize}
        break // Break inner read loop for current seq
    } else if rcode != ICMP_ECHO_REPLY || rseq != seq || rid != sendid { // Not the expected reply for the current 'seq'
        continue // Discard this packet and try reading again
    } else { // Expected reply for the current 'seq'
        response <- Response{Delay: elapsed, Error: err, Destination: raddr.IP.String(), Seq: seq, Writesize: writesize, Readsize: readsize}
        break // Break inner read loop for current seq
    }
}
// ...

type PingResult struct {
    Seq      int
    Status   string // "Success", "Timeout", "LateReply"
    Delay    time.Duration
    // ...
}

// GetLateReplies returns a list of replies that arrived after their timeout was reported.
func (p *Pinger) GetLateReplies() []PingResult {
    // ... internal logic to return late replies
}

// PingOptions allows configuring optional behaviors for Pinguntil.
type PingOptions struct {
    Delay       time.Duration // Delay between successive pings
    OnLateReply chan Response // Optional channel to receive replies that arrived after timeout
}

// Pinguntil sends ICMP echo packets to the destination.
// It reports primary responses to the 'response' channel and late replies to 'options.OnLateReply' if provided.
func Pinguntil(destination string, count int, response chan Response, options PingOptions) {
    // ... implementation
}

package libping

import (
    "bytes"
    "net"
    "os"
    "time"
)

const (
    ICMP_ECHO_REQUEST = 8
    ICMP_ECHO_REPLY   = 0
)

// The struct Response is the data returned by Pinguntil.
type Response struct {
    Delay       time.Duration
    Error       error
    Destination string
    Seq         int
    Readsize    int
    Writesize   int
    IsLateReply bool // New field to indicate if this is a late reply
}

// PingOptions allows configuring optional behaviors for Pinguntil.
type PingOptions struct {
    Delay       time.Duration // Delay between successive pings
    OnLateReply chan Response // Optional channel to receive replies that arrived after timeout
    Timeout     time.Duration // Per-packet read timeout
}

// makePingRequest and parsePingReply functions remain the same
// ... (omitted for brevity)

// Pingonce sends one ICMP echo packet.
func Pingonce(destination string) (time.Duration, error) {
    response := make(chan Response)
    options := PingOptions{Timeout: time.Second}
    go Pinguntil(destination, 1, response, options)
    answer := <-response
    return answer.Delay, answer.Error
}

// Pinguntil will send ICMP echo packets to the destination until the counter is reached,
// or forever if the counter is set to 0.
// Replies are given in the 'response' channel. Late replies can be sent to 'options.OnLateReply'.
func Pinguntil(destination string, count int, response chan Response, options PingOptions) {
    raddr, err := net.ResolveIPAddr("ip", destination)
    if err != nil {
        response <- Response{Delay: 0, Error: err, Destination: destination, Seq: 0}
        close(response)
        return
    }

    ipconn, err := net.Dial("ip:icmp", raddr.IP.String())
    if err != nil {
        response <- Response{Delay: 0, Error: err, Destination: raddr.IP.String(), Seq: 0}
        close(response)
        return
    }
    defer ipconn.Close() // Ensure connection is closed

    sendid := os.Getpid() & 0xffff
    pingpktlen := 64
    seq := 0

    // Default timeout if not specified
    if options.Timeout == 0 {
        options.Timeout = time.Second
    }
    // Default delay if not specified
    if