initial sip implementation

7 files changed, 270 insertions, 6 deletions

diff --git a/cmd/vpnweb/vpnweb.go b/cmd/vpnweb/vpnweb.go
index 2305d98..ff25e09 100644
--- a/cmd/vpnweb/vpnweb.go
+++ b/cmd/vpnweb/vpnweb.go
@@ -21,11 +21,11 @@ func main() {
 	/* protected routes */
 
 	/* TODO ----
-	http.HandleFunc("/3/auth", auth.AuthMiddleware(opts.Auth))
 	http.HandleFunc("/3/refresh-token", auth.RefreshAuthMiddleware(opts.Auth))
 	*/
 
-	http.Handle("/3/cert", auth.AuthMiddleware(opts.Auth, ch))
+	http.Handle("/3/cert", auth.RestrictedMiddleware(opts.Auth, ch))
+	http.Handle("/3/auth", auth.Authenticator(opts.Auth))
 
 	/* static files */
 
diff --git a/go.mod b/go.mod
index 11be102..55f4406 100644
--- a/go.mod
+++ b/go.mod
@@ -8,5 +8,7 @@ require (
 	github.com/dgrijalva/jwt-go v3.2.0+incompatible
 	github.com/go-martini/martini v0.0.0-20170121215854-22fa46961aab // indirect
 	github.com/gorilla/mux v1.7.3 // indirect
+	github.com/reiver/go-oi v1.0.0 // indirect
+	github.com/reiver/go-telnet v0.0.0-20180421082511-9ff0b2ab096e
 	github.com/urfave/negroni v1.0.0 // indirect
 )
diff --git a/go.sum b/go.sum
index 7211e92..6f0e519 100644
--- a/go.sum
+++ b/go.sum
@@ -8,5 +8,9 @@ github.com/go-martini/martini v0.0.0-20170121215854-22fa46961aab h1:xveKWz2iauee
 github.com/go-martini/martini v0.0.0-20170121215854-22fa46961aab/go.mod h1:/P9AEU963A2AYjv4d1V5eVL1CQbEJq6aCNHDDjibzu8=
 github.com/gorilla/mux v1.7.3 h1:gnP5JzjVOuiZD07fKKToCAOjS0yOpj/qPETTXCCS6hw=
 github.com/gorilla/mux v1.7.3/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
+github.com/reiver/go-oi v1.0.0 h1:nvECWD7LF+vOs8leNGV/ww+F2iZKf3EYjYZ527turzM=
+github.com/reiver/go-oi v1.0.0/go.mod h1:RrDBct90BAhoDTxB1fenZwfykqeGvhI6LsNfStJoEkI=
+github.com/reiver/go-telnet v0.0.0-20180421082511-9ff0b2ab096e h1:quuzZLi72kkJjl+f5AQ93FMcadG19WkS7MO6TXFOSas=
+github.com/reiver/go-telnet v0.0.0-20180421082511-9ff0b2ab096e/go.mod h1:+5vNVvEWwEIx86DB9Ke/+a5wBI464eDRo3eF0LcfpWg=
 github.com/urfave/negroni v1.0.0 h1:kIimOitoypq34K7TG7DUaJ9kq/N4Ofuwi1sjz0KipXc=
 github.com/urfave/negroni v1.0.0/go.mod h1:Meg73S6kFm/4PpbYdq35yYWoCZ9mS/YSx+lKnmiohz4=
diff --git a/pkg/auth/middleware.go b/pkg/auth/middleware.go
index 5fe0ab7..a183c1b 100644
--- a/pkg/auth/middleware.go
+++ b/pkg/auth/middleware.go
@@ -11,14 +11,13 @@ import (
 const anonAuth string = "anon"
 const sipAuth string = "sip"
 
+/* FIXME -- get this from configuration variables */
 var jwtSecret = []byte("somethingverysecret")
 
-func getHandler(ch web.CertHandler) func(w http.ResponseWriter, r *http.Request) {
-	return ch.CertResponder
+func Authenticator(auth string) {
 }
 
-//func AuthMiddleware(auth string, ch web.CertHandler) func(w http.ResponseWriter, r *http.Request) {
-func AuthMiddleware(auth string, ch web.CertHandler) http.Handler {
+func RestrictedMiddleware(auth string, ch web.CertHandler) http.Handler {
 
 	jwtMiddleware := jwtmiddleware.New(jwtmiddleware.Options{
 		ValidationKeyGetter: func(token *jwt.Token) (interface{}, error) {
@@ -38,5 +37,6 @@ func AuthMiddleware(auth string, ch web.CertHandler) http.Handler {
 	default:
 		log.Fatal("Unknown auth module: '", auth, "'. Should be one of: ", anonAuth, ", ", sipAuth, ".")
 	}
+	// should not get here
 	return nil
 }
diff --git a/pkg/auth/sip2/client.go b/pkg/auth/sip2/client.go
new file mode 100644
index 0000000..fbdeded
--- /dev/null
+++ b/pkg/auth/sip2/client.go
@@ -0,0 +1,74 @@
+package sip2
+
+import (
+	"fmt"
+	"github.com/reiver/go-telnet"
+	"log"
+	"time"
+)
+
+const loginRequestTemplate string = "9300CN%s|CO%s|CP%s|"
+const statusRequestTemplate string = "23000%s    %sAO%s|AA%s|AD%s|"
+
+type Client struct {
+	Host     string
+	Port     string
+	location string
+	conn     *telnet.Conn
+	parser   *Parser
+}
+
+func NewClient(host, port, location string) Client {
+	c := Client{host, port, location, nil, nil}
+	c.parser = getParser()
+	return c
+}
+
+func (c *Client) Connect() (bool, error) {
+	conn, err := telnet.DialTo(c.Host + ":" + c.Port)
+	if nil != err {
+		log.Println(log.Printf("error: %v", err))
+		return false, err
+	}
+	c.conn = conn
+	return true, nil
+}
+
+func (c *Client) Login(user, pass string) bool {
+	loginStr := fmt.Sprintf(loginRequestTemplate, user, pass, c.location)
+	if nil == c.conn {
+		fmt.Println("error! null connection")
+	}
+	telnetSend(c.conn, loginStr)
+	loginResp := telnetRead(c.conn)
+	msg := c.parseResponse(loginResp)
+	if value, ok := c.parser.getFixedFieldValue(msg, Ok); ok && value == TRUE {
+		return true
+	}
+	return false
+}
+
+func (c *Client) CheckCredentials(user, passwd string) bool {
+	currentTime := time.Now()
+	statusRequest := fmt.Sprintf(
+		statusRequestTemplate,
+		currentTime.Format("20060102"),
+		currentTime.Format("150102"),
+		c.location, user, passwd)
+	telnetSend(c.conn, statusRequest)
+
+	statusMsg := c.parseResponse(telnetRead(c.conn))
+	if value, ok := c.parser.getFieldValue(statusMsg, ValidPatron); ok && value == YES {
+		if value, ok := c.parser.getFieldValue(statusMsg, ValidPatronPassword); ok && value == YES {
+			return true
+		}
+	}
+
+	// TODO log whatever error we can find (AF, Screen Message, for instance)
+	return false
+}
+
+func (c *Client) parseResponse(txt string) *Message {
+	msg := c.parser.parseMessage(txt)
+	return msg
+}
diff --git a/pkg/auth/sip2/spec.go b/pkg/auth/sip2/spec.go
new file mode 100644
index 0000000..9c4ac48
--- /dev/null
+++ b/pkg/auth/sip2/spec.go
@@ -0,0 +1,141 @@
+package sip2
+
+import (
+	"log"
+	"strconv"
+	"strings"
+)
+
+type FixedFieldSpec struct {
+	length int
+	label  string
+}
+
+type FixedField struct {
+	spec  FixedFieldSpec
+	value string
+}
+
+type VariableFieldSpec struct {
+	id    string
+	label string
+}
+
+type VariableField struct {
+	spec  VariableFieldSpec
+	value string
+}
+
+type MessageSpec struct {
+	id     int
+	label  string
+	fields []FixedFieldSpec
+}
+
+type Message struct {
+	fields       []VariableField
+	fixed_fields []FixedField
+	msg_txt      string
+}
+
+type Parser struct {
+	getMessageSpecByCode   func(int) MessageSpec
+	getVariableFieldByCode func(string) VariableFieldSpec
+	getFixedFieldValue     func(*Message, string) (string, bool)
+	getFieldValue          func(*Message, string) (string, bool)
+	parseMessage           func(string) *Message
+}
+
+const (
+	YES                  string = "Y"
+	TRUE                 string = "1"
+	Ok                   string = "ok"
+	Language             string = "language"
+	PatronStatus         string = "patron status"
+	Date                 string = "transaction date"
+	PatronIdentifier     string = "patron identifier"
+	PatronPassword       string = "patron password"
+	PersonalName         string = "personal name"
+	ScreenMessage        string = "screen message"
+	InstitutionId        string = "institution id"
+	ValidPatron          string = "valid patron"
+	ValidPatronPassword  string = "valid patron password"
+	LoginResponse        string = "Login Response"
+	PatronStatusResponse string = "Patron Status Response"
+)
+
+func getParser() *Parser {
+
+	LanguageSpec := FixedFieldSpec{3, Language}
+	PatronStatusSpec := FixedFieldSpec{14, PatronStatus}
+	DateSpec := FixedFieldSpec{18, Date}
+	OkSpec := FixedFieldSpec{1, Ok}
+
+	msgByCodeMap := map[int]MessageSpec{
+		94: MessageSpec{94, LoginResponse, []FixedFieldSpec{OkSpec}},
+		24: MessageSpec{24, PatronStatusResponse, []FixedFieldSpec{PatronStatusSpec, LanguageSpec, DateSpec}},
+	}
+
+	variableFieldByCodeMap := map[string]VariableFieldSpec{
+		"AA": VariableFieldSpec{"AA", PatronIdentifier},
+		"AD": VariableFieldSpec{"AD", PatronPassword},
+		"AE": VariableFieldSpec{"AE", PersonalName},
+		"AF": VariableFieldSpec{"AF", ScreenMessage},
+		"AO": VariableFieldSpec{"AO", InstitutionId},
+		"BL": VariableFieldSpec{"BL", ValidPatron},
+		"CQ": VariableFieldSpec{"CQ", ValidPatronPassword},
+	}
+
+	parser := new(Parser)
+	parser.getMessageSpecByCode = func(code int) MessageSpec {
+		return msgByCodeMap[code]
+	}
+	parser.getVariableFieldByCode = func(code string) VariableFieldSpec {
+		return variableFieldByCodeMap[code]
+	}
+	parser.getFixedFieldValue = func(msg *Message, field string) (string, bool) {
+		for _, v := range msg.fixed_fields {
+			if v.spec.label == field {
+				return v.value, true
+			}
+		}
+		return "", false
+	}
+	parser.getFieldValue = func(msg *Message, field string) (string, bool) {
+		for _, v := range msg.fields {
+			if v.spec.label == field {
+				return v.value, true
+			}
+		}
+		return "", false
+	}
+
+	parser.parseMessage = func(msg string) *Message {
+		txt := msg[:len(msg)-len(terminator)]
+		code, err := strconv.Atoi(txt[:2])
+		if nil != err {
+			log.Println("Error parsing integer: %s", txt[:2])
+		}
+		spec := parser.getMessageSpecByCode(code)
+		txt = txt[2:]
+
+		message := new(Message)
+		for _, sp := range spec.fields {
+			value := txt[:sp.length]
+			txt = txt[sp.length:]
+			message.fixed_fields = append(message.fixed_fields, FixedField{sp, value})
+		}
+		if len(txt) == 0 {
+			return message
+		}
+		for _, part := range strings.Split(txt, "|") {
+			if len(part) > 0 {
+				part_spec := parser.getVariableFieldByCode(part[:2])
+				value := part[2:]
+				message.fields = append(message.fields, VariableField{part_spec, value})
+			}
+		}
+		return message
+	}
+	return parser
+}
diff --git a/pkg/auth/sip2/telnet.go b/pkg/auth/sip2/telnet.go
new file mode 100644
index 0000000..b5abd5f
--- /dev/null
+++ b/pkg/auth/sip2/telnet.go
@@ -0,0 +1,43 @@
+package sip2
+
+import (
+	"github.com/reiver/go-telnet"
+)
+
+// TODO depends on how terminator is configured -- take it from config file
+// const terminator string = "\r\n"
+const terminator string = "\r"
+
+func telnetRead(conn *telnet.Conn) (out string) {
+	var buffer [1]byte
+	recvData := buffer[:]
+	var n int
+	var err error
+
+	for {
+		n, err = conn.Read(recvData)
+		if n <= 0 || err != nil {
+			break
+		} else {
+			out += string(recvData)
+		}
+		if len(out) > 1 && out[len(out)-len(terminator):] == terminator {
+			break
+		}
+	}
+	return out
+}
+
+func telnetSend(conn *telnet.Conn, command string) {
+	var commandBuffer []byte
+	for _, char := range command {
+		commandBuffer = append(commandBuffer, byte(char))
+	}
+
+	var crlfBuffer [2]byte = [2]byte{'\r', '\n'}
+
+	crlf := crlfBuffer[:]
+
+	conn.Write(commandBuffer)
+	conn.Write(crlf)
+}