feat(icmp) support DoNotFragment + Size

README.md

@@ -48,7 +48,6 @@ Have any feedback or questions? [Create a discussion](https://github.com/TwiN/ga
   - [Storage](#storage)
   - [Client configuration](#client-configuration)
   - [Alerting](#alerting)
-    - [Configuring AWS SES alerts](#configuring-aws-ses-alerts)
     - [Configuring Discord alerts](#configuring-discord-alerts)
     - [Configuring Email alerts](#configuring-email-alerts)
     - [Configuring GitHub alerts](#configuring-github-alerts)
@@ -66,6 +65,7 @@ Have any feedback or questions? [Create a discussion](https://github.com/TwiN/ga
     - [Configuring Teams alerts](#configuring-teams-alerts)
     - [Configuring Telegram alerts](#configuring-telegram-alerts)
     - [Configuring Twilio alerts](#configuring-twilio-alerts)
+    - [Configuring AWS SES alerts](#configuring-aws-ses-alerts)
     - [Configuring custom alerts](#configuring-custom-alerts)
     - [Setting a default alert](#setting-a-default-alert)
   - [Maintenance](#maintenance)
@@ -109,7 +109,6 @@ Have any feedback or questions? [Create a discussion](https://github.com/TwiN/ga
   - [API](#api)
   - [Installing as binary](#installing-as-binary)
   - [High level design overview](#high-level-design-overview)
-- [Sponsors](#sponsors)
 
 
 ## Why Gatus?
@@ -352,6 +351,8 @@ the client used to send the request.
 | `client.ignore-redirect`               | Whether to ignore redirects (true) or follow them (false, default).         | `false`         |
 | `client.timeout`                       | Duration before timing out.                                                 | `10s`           |
 | `client.dns-resolver`                  | Override the DNS resolver using the format `{proto}://{host}:{port}`.       | `""`            |
+| `client.icmp.df`                       | Option to set the DoNotFragement bit for ICMP packet                        | `false`         |
+| `client.icmp.size`                     | Size of the ICMP packet                                                     | `25`            |
 | `client.oauth2`                        | OAuth2 client configuration.                                                | `{}`            |
 | `client.oauth2.token-url`              | The token endpoint URL                                                      | required `""`   |
 | `client.oauth2.client-id`              | The client id which should be used for the `Client credentials flow`        | required `""`   |
@@ -363,6 +364,8 @@ the client used to send the request.
 > 📝 Some of these parameters are ignored based on the type of endpoint. For instance, there's no certificate involved
 in ICMP requests (ping), therefore, setting `client.insecure` to `true` for an endpoint of that type will not do anything.
 
+> 📝 The ICMP parameters, including size and the 'Don't Fragment' (DF) flag, are utilized exclusively for ICMP pings. [These parameters can be used to validate MTU](https://stackoverflow.com/questions/45953716/when-to-set-dont-fragment-flag-in-ip-header)
+
 This default configuration is as follows:
 ```yaml
 client:

client/client.go

@@ -241,12 +241,16 @@ func Ping(address string, config *Config) (bool, time.Duration) {
 	}
 	pinger.Count = 1
 	pinger.Timeout = config.Timeout
+	pinger.Size = config.Icmp.Size
 	// Set the pinger's privileged mode to true for every GOOS except darwin
 	// See https://github.com/TwiN/gatus/issues/132
 	//
 	// Note that for this to work on Linux, Gatus must run with sudo privileges.
 	// See https://github.com/prometheus-community/pro-bing#linux
 	pinger.SetPrivileged(runtime.GOOS != "darwin")
+	if config.Icmp.Df {
+		pinger.SetDoNotFragment(true)
+	}
 	err = pinger.Run()
 	if err != nil {
 		return false, 0

client/config.go

@@ -18,6 +18,8 @@ import (
 
 const (
 	defaultTimeout = 10 * time.Second
+	// By default, an ICMP packet can have a size of 0
+	defaultSize = 0
 )
 
 var (
@@ -30,6 +32,10 @@ var (
 		Insecure:       false,
 		IgnoreRedirect: false,
 		Timeout:        defaultTimeout,
+		Icmp: &Icmp{ 
+			Df:   false,
+			Size: defaultSize,
+		},
 	}
 )
 
@@ -54,6 +60,9 @@ type Config struct {
 	// Expected format is {protocol}://{host}:{port}, e.g. tcp://8.8.8.8:53
 	DNSResolver string `yaml:"dns-resolver,omitempty"`
 
+	// See ICMP for more details.
+	Icmp *Icmp `yaml:"icmp,omitempty"`
+
 	// OAuth2Config is the OAuth2 configuration used for the client.
 	//
 	// If non-nil, the http.Client returned by getHTTPClient will automatically retrieve a token if necessary.
@@ -73,6 +82,14 @@ type DNSResolverConfig struct {
 	Port     string
 }
 
+// ICMP is the configuration for the ICMP client specific config
+type Icmp struct {
+	// Don't Fragment flag (DF) for the client
+	Df bool `yaml:"df"`
+	// Size of the packet
+	Size int `yaml:"size"`
+}
+
 // OAuth2Config is the configuration for the OAuth2 client credentials flow
 type OAuth2Config struct {
 	TokenURL     string   `yaml:"token-url"` // e.g. https://dev-12345678.okta.com/token
@@ -91,6 +108,20 @@ func (c *Config) ValidateAndSetDefaults() error {
 	if c.Timeout < time.Millisecond {
 		c.Timeout = 10 * time.Second
 	}
+
+    // Only validate or set defaults for Icmp if it's not nil
+    if c.Icmp != nil {
+        // limit for pro-ping, below 25 it's not working
+        if c.Icmp.Size < 25 {
+            c.Icmp.Size = 25
+        }
+    } else {
+        // If Icmp is nil, let's initialize it with default values
+        c.Icmp = &Icmp{
+            Df:   false,
+            Size: 25,  
+        }
+    }
 	if c.HasCustomDNSResolver() {
 		// Validate the DNS resolver now to make sure it will not return an error later.
 		if _, err := c.parseDNSResolver(); err != nil {