From 83ff88e35bf80e105b73fde758f52c7256cbc975 Mon Sep 17 00:00:00 2001
From: Jozef Reisinger <jozef.reisinger@gmail.com>
Date: Tue, 16 May 2023 11:20:46 +0200
Subject: [PATCH] Add check to see if an IP belongs to AWS (close #40)

---
 check/check.go        |  2 ++
 check/http.go         |  2 +-
 check/isonaws.go      | 70 +++++++++++++++++++++++++++++++++++++++++++
 check/isonaws_test.go | 35 ++++++++++++++++++++++
 4 files changed, 108 insertions(+), 1 deletion(-)
 create mode 100644 check/isonaws.go
 create mode 100644 check/isonaws_test.go

diff --git a/check/check.go b/check/check.go
index db0f47f..ffe0915 100644
--- a/check/check.go
+++ b/check/check.go
@@ -18,6 +18,7 @@ var All = []checkip.Check{
 	Firehol,
 	IPSum,
 	IPtoASN,
+	IsOnAWS,
 	MaxMind,
 	OTX,
 	PhishStats,
@@ -38,6 +39,7 @@ var Default = []checkip.Check{
 	Firehol,
 	IPSum,
 	IPtoASN,
+	IsOnAWS,
 	OTX,
 	Ping,
 	Shodan,
diff --git a/check/http.go b/check/http.go
index 2cf1a89..6c99c09 100644
--- a/check/http.go
+++ b/check/http.go
@@ -10,7 +10,7 @@ import (
 )
 
 // defaultHttpClient is reused by checks that make HTTP requests.
-var defaultHttpClient = newHttpClient(&http.Client{Timeout: 5 * time.Second})
+var defaultHttpClient = newHttpClient(&http.Client{Timeout: 10 * time.Second})
 
 type httpClient struct {
 	client *http.Client
diff --git a/check/isonaws.go b/check/isonaws.go
new file mode 100644
index 0000000..7b0e1f0
--- /dev/null
+++ b/check/isonaws.go
@@ -0,0 +1,70 @@
+package check
+
+import (
+	"encoding/json"
+	"fmt"
+	"net"
+
+	"github.com/jreisinger/checkip"
+)
+
+type awsIpRanges struct {
+	IsOn bool
+	Info struct {
+		IpPrefix           string   `json:"ip_prefix"`
+		Region             string   `json:"region"`
+		Services           []string `json:"services"`
+		NetworkBorderGroup string   `json:"network_border_group"`
+	}
+}
+
+// Json implements checkip.Info
+func (a awsIpRanges) Json() ([]byte, error) {
+	return json.Marshal(&a)
+}
+
+// Summary implements checkip.Info
+func (a awsIpRanges) Summary() string {
+	if a.IsOn {
+		return fmt.Sprintf("%t, prefix: %s, region: %s, sevices: %v",
+			a.IsOn, a.Info.IpPrefix, a.Info.Region, a.Info.Services)
+	}
+	return fmt.Sprintf("%t", a.IsOn)
+}
+
+// IsOnAWS checks if ipaddr belongs to AWS. If so it provides info about the IP
+// address. It gets the info from https://ip-ranges.amazonaws.com/ip-ranges.json
+func IsOnAWS(ipaddr net.IP) (checkip.Result, error) {
+	result := checkip.Result{
+		Name: "is on AWS",
+	}
+	resp := struct {
+		Prefixes []struct {
+			IpPrefix           string `json:"ip_prefix"`
+			Region             string `json:"region"`
+			Service            string `json:"service"`
+			NetworkBorderGroup string `json:"network_border_group"`
+		} `json:"prefixes"`
+	}{}
+	apiUrl := "https://ip-ranges.amazonaws.com/ip-ranges.json"
+	if err := defaultHttpClient.GetJson(apiUrl, map[string]string{}, map[string]string{}, &resp); err != nil {
+		return result, newCheckError(err)
+	}
+	var a awsIpRanges
+	for _, prefix := range resp.Prefixes {
+		_, network, err := net.ParseCIDR(prefix.IpPrefix)
+		if err != nil {
+			return result, fmt.Errorf("parse CIDR %q: %v", prefix.IpPrefix, err)
+		}
+		if network.Contains(ipaddr) {
+			a.IsOn = true
+			a.Info.IpPrefix = prefix.IpPrefix
+			a.Info.NetworkBorderGroup = prefix.NetworkBorderGroup
+			a.Info.Region = prefix.Region
+			a.Info.Services = append(a.Info.Services, prefix.Service)
+		}
+
+	}
+	result.Info = a
+	return result, nil
+}
diff --git a/check/isonaws_test.go b/check/isonaws_test.go
new file mode 100644
index 0000000..52223ba
--- /dev/null
+++ b/check/isonaws_test.go
@@ -0,0 +1,35 @@
+package check_test
+
+import (
+	"net"
+	"testing"
+
+	"github.com/jreisinger/checkip/check"
+)
+
+func TestIsOnAWS(t *testing.T) {
+	tests := []struct {
+		ipAddr  string
+		summary string
+	}{
+		{
+			ipAddr:  "54.74.0.27",
+			summary: "true, prefix: 54.74.0.0/15, region: eu-west-1, sevices: [AMAZON EC2]",
+		},
+		{
+			ipAddr:  "1.1.1.1",
+			summary: "false",
+		},
+	}
+
+	for i, test := range tests {
+		ipaddr := net.ParseIP(test.ipAddr)
+		r, err := check.IsOnAWS(ipaddr)
+		if err != nil {
+			t.Fatalf("check.IsOnAWS(%s) failed: %v", ipaddr, err)
+		}
+		if r.Info.Summary() != test.summary {
+			t.Errorf("test %d\ngot\t%q\nwant\t%q", i, r.Info.Summary(), test.summary)
+		}
+	}
+}