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agnhost/netexec: logging cleanup and print more verbose errors

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There's currently no way to know whether an error is for SCTP or
UDP, for example:

Jul 24 09:55:54.469: INFO: netserver-0[e2e-nettest-3476].container[webserver].log
2020/07/24 09:53:52 Started UDP server
2020/07/24 09:53:52 Error occurred. error:protocol not supported

In this case the "Error occurred. error:protocol not supported" is
actually for the SCTP socket. Make that more apparent.
This commit is contained in:
Dan Williams 2020-07-24 14:35:14 -05:00
parent 1ed2cf1895
commit 31c563a46f
1 changed files with 25 additions and 25 deletions
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50
test/images/agnhost/netexec/netexec.go
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@ -491,9 +491,9 @@ func hostNameHandler(w http.ResponseWriter, r *http.Request) {
// udp server supports the hostName, echo and clientIP commands. // udp server supports the hostName, echo and clientIP commands.
func startUDPServer(udpPort int) { func startUDPServer(udpPort int) {
serverAddress, err := net.ResolveUDPAddr("udp", fmt.Sprintf(":%d", udpPort)) serverAddress, err := net.ResolveUDPAddr("udp", fmt.Sprintf(":%d", udpPort))
assertNoError(err) assertNoError(err, fmt.Sprintf("failed to resolve UDP address for port %d", sctpPort))
serverConn, err := net.ListenUDP("udp", serverAddress) serverConn, err := net.ListenUDP("udp", serverAddress)
assertNoError(err) assertNoError(err, fmt.Sprintf("failed to create listener for UDP address %v", serverAddress))
defer serverConn.Close() defer serverConn.Close()
buf := make([]byte, 2048) buf := make([]byte, 2048)
@ -506,27 +506,27 @@ func startUDPServer(udpPort int) {
}() }()
for { for {
n, clientAddress, err := serverConn.ReadFromUDP(buf) n, clientAddress, err := serverConn.ReadFromUDP(buf)
assertNoError(err) assertNoError(err, fmt.Sprintf("failed accepting UDP connections"))
receivedText := strings.ToLower(strings.TrimSpace(string(buf[0:n]))) receivedText := strings.ToLower(strings.TrimSpace(string(buf[0:n])))
if receivedText == "hostname" { if receivedText == "hostname" {
log.Println("Sending udp hostName response") log.Println("Sending udp hostName response")
_, err = serverConn.WriteToUDP([]byte(getHostName()), clientAddress) _, err = serverConn.WriteToUDP([]byte(getHostName()), clientAddress)
assertNoError(err) assertNoError(err, fmt.Sprintf("failed to write hostname to UDP client %s", clientAddress))
} else if strings.HasPrefix(receivedText, "echo ") { } else if strings.HasPrefix(receivedText, "echo ") {
parts := strings.SplitN(receivedText, " ", 2) parts := strings.SplitN(receivedText, " ", 2)
resp := "" resp := ""
if len(parts) == 2 { if len(parts) == 2 {
resp = parts[1] resp = parts[1]
} }
log.Printf("Echoing %v\n", resp) log.Printf("Echoing %v to UDP client %s\n", resp, clientAddress)
_, err = serverConn.WriteToUDP([]byte(resp), clientAddress) _, err = serverConn.WriteToUDP([]byte(resp), clientAddress)
assertNoError(err) assertNoError(err, fmt.Sprintf("failed to echo to UDP client %s", clientAddress))
} else if receivedText == "clientip" { } else if receivedText == "clientip" {
log.Printf("Sending back clientip to %s", clientAddress.String()) log.Printf("Sending clientip back to UDP client %s\n", clientAddress)
_, err = serverConn.WriteToUDP([]byte(clientAddress.String()), clientAddress) _, err = serverConn.WriteToUDP([]byte(clientAddress.String()), clientAddress)
assertNoError(err) assertNoError(err, fmt.Sprintf("failed to write clientip to UDP client %s", clientAddress))
} else if len(receivedText) > 0 { } else if len(receivedText) > 0 {
log.Printf("Unknown udp command received: %v\n", receivedText) log.Printf("Unknown UDP command received from %s: %v\n", clientAddress, receivedText)
} }
} }
} }
@ -534,9 +534,9 @@ func startUDPServer(udpPort int) {
// sctp server supports the hostName, echo and clientIP commands. // sctp server supports the hostName, echo and clientIP commands.
func startSCTPServer(sctpPort int) { func startSCTPServer(sctpPort int) {
serverAddress, err := sctp.ResolveSCTPAddr("sctp", fmt.Sprintf(":%d", sctpPort)) serverAddress, err := sctp.ResolveSCTPAddr("sctp", fmt.Sprintf(":%d", sctpPort))
assertNoError(err) assertNoError(err, fmt.Sprintf("failed to resolve SCTP address for port %d", sctpPort))
listener, err := sctp.ListenSCTP("sctp", serverAddress) listener, err := sctp.ListenSCTP("sctp", serverAddress)
assertNoError(err) assertNoError(err, fmt.Sprintf("failed to create listener for SCTP address %v", serverAddress))
defer listener.Close() defer listener.Close()
buf := make([]byte, 1024) buf := make([]byte, 1024)
@ -549,30 +549,30 @@ func startSCTPServer(sctpPort int) {
}() }()
for { for {
conn, err := listener.AcceptSCTP() conn, err := listener.AcceptSCTP()
assertNoError(err) assertNoError(err, fmt.Sprintf("failed accepting SCTP connections"))
clientAddress := conn.RemoteAddr().String()
n, err := conn.Read(buf) n, err := conn.Read(buf)
assertNoError(err) assertNoError(err, fmt.Sprintf("failed to read from SCTP client %s", clientAddress))
receivedText := strings.ToLower(strings.TrimSpace(string(buf[0:n]))) receivedText := strings.ToLower(strings.TrimSpace(string(buf[0:n])))
if receivedText == "hostname" { if receivedText == "hostname" {
log.Println("Sending sctp hostName response") log.Println("Sending SCTP hostName response")
_, err = conn.Write([]byte(getHostName())) _, err = conn.Write([]byte(getHostName()))
assertNoError(err) assertNoError(err, fmt.Sprintf("failed to write hostname to SCTP client %s", clientAddress))
} else if strings.HasPrefix(receivedText, "echo ") { } else if strings.HasPrefix(receivedText, "echo ") {
parts := strings.SplitN(receivedText, " ", 2) parts := strings.SplitN(receivedText, " ", 2)
resp := "" resp := ""
if len(parts) == 2 { if len(parts) == 2 {
resp = parts[1] resp = parts[1]
} }
log.Printf("Echoing %v\n", resp) log.Printf("Echoing %v to SCTP client %s\n", resp, clientAddress)
_, err = conn.Write([]byte(resp)) _, err = conn.Write([]byte(resp))
assertNoError(err) assertNoError(err, fmt.Sprintf("failed to echo to SCTP client %s", clientAddress))
} else if receivedText == "clientip" { } else if receivedText == "clientip" {
clientAddress := conn.RemoteAddr() log.Printf("Sending clientip back to SCTP client %s\n", clientAddress)
log.Printf("Sending back clientip to %s", clientAddress.String()) _, err = conn.Write([]byte(clientAddress))
_, err = conn.Write([]byte(clientAddress.String())) assertNoError(err, fmt.Sprintf("failed to write clientip to SCTP client %s", clientAddress))
assertNoError(err)
} else if len(receivedText) > 0 { } else if len(receivedText) > 0 {
log.Printf("Unknown sctp command received: %v\n", receivedText) log.Printf("Unknown SCTP command received from %s: %v\n", clientAddress, receivedText)
} }
conn.Close() conn.Close()
} }
@ -580,12 +580,12 @@ func startSCTPServer(sctpPort int) {
func getHostName() string { func getHostName() string {
hostName, err := os.Hostname() hostName, err := os.Hostname()
assertNoError(err) assertNoError(err, "failed to get hostname")
return hostName return hostName
} }
func assertNoError(err error) { func assertNoError(err error, detail string) {
if err != nil { if err != nil {
log.Fatal("Error occurred. error:", err) log.Fatalf("Error occurred: %s:%v", detail, err)
} }
} }