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mirror of https://github.com/ribbybibby/ssl_exporter.git synced 2024-11-24 08:22:17 +02:00
ssl_exporter/prober/tcp.go
Rob Best c74c0de901 Refactor prober function and metrics collection
The existing implementation consists of a collector that exports
information from a tls.ConnectionState returned by the prober function.
This won't necessarily integrate well with additional probers that
retrieve certs from sources other than a tls handshake (from file, for
instance).

I've made the probing more generically expandable by removing the
collector and instead registering and collecting metrics inside the
prober. This makes it possible to collect the same metrics in a
different way, or collect different metrics depending on the prober.
2020-11-07 17:17:06 +00:00

152 lines
3.0 KiB
Go

package prober
import (
"bufio"
"crypto/tls"
"fmt"
"net"
"regexp"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/log"
"github.com/ribbybibby/ssl_exporter/config"
)
// ProbeTCP performs a tcp probe
func ProbeTCP(target string, module config.Module, timeout time.Duration, registry *prometheus.Registry) error {
tlsConfig, err := newTLSConfig(target, registry, &module.TLSConfig)
if err != nil {
return err
}
dialer := &net.Dialer{Timeout: timeout}
conn, err := dialer.Dial("tcp", target)
if err != nil {
return err
}
defer conn.Close()
if err := conn.SetDeadline(time.Now().Add(timeout)); err != nil {
return fmt.Errorf("Error setting deadline")
}
if module.TCP.StartTLS != "" {
err = startTLS(conn, module.TCP.StartTLS)
if err != nil {
return err
}
}
tlsConn := tls.Client(conn, tlsConfig)
defer tlsConn.Close()
return tlsConn.Handshake()
}
type queryResponse struct {
expect string
send string
}
var (
// These are the protocols for which I had servers readily available to test
// against. There are plenty of other protocols that should be added here in
// the future.
//
// See openssl s_client for more examples:
// https://github.com/openssl/openssl/blob/openssl-3.0.0-alpha3/apps/s_client.c#L2229-L2728
startTLSqueryResponses = map[string][]queryResponse{
"smtp": []queryResponse{
queryResponse{
expect: "^220",
},
queryResponse{
send: "EHLO prober",
},
queryResponse{
expect: "^250-STARTTLS",
},
queryResponse{
send: "STARTTLS",
},
queryResponse{
expect: "^220",
},
},
"ftp": []queryResponse{
queryResponse{
expect: "^220",
},
queryResponse{
send: "AUTH TLS",
},
queryResponse{
expect: "^234",
},
},
"imap": []queryResponse{
queryResponse{
expect: "OK",
},
queryResponse{
send: ". CAPABILITY",
},
queryResponse{
expect: "STARTTLS",
},
queryResponse{
expect: "OK",
},
queryResponse{
send: ". STARTTLS",
},
queryResponse{
expect: "OK",
},
},
}
)
// startTLS will send the STARTTLS command for the given protocol
func startTLS(conn net.Conn, proto string) error {
var err error
qr, ok := startTLSqueryResponses[proto]
if !ok {
return fmt.Errorf("STARTTLS is not supported for %s", proto)
}
scanner := bufio.NewScanner(conn)
for _, qr := range qr {
if qr.expect != "" {
var match bool
for scanner.Scan() {
log.Debugf("read line: %s", scanner.Text())
match, err = regexp.Match(qr.expect, scanner.Bytes())
if err != nil {
return err
}
if match {
log.Debugf("regex: %s matched: %s", qr.expect, scanner.Text())
break
}
}
if scanner.Err() != nil {
return scanner.Err()
}
if !match {
return fmt.Errorf("regex: %s didn't match: %s", qr.expect, scanner.Text())
}
}
if qr.send != "" {
log.Debugf("sending line: %s", qr.send)
if _, err := fmt.Fprintf(conn, "%s\r\n", qr.send); err != nil {
return err
}
}
}
return nil
}