smtpd

package
v0.0.0-...-c7a3bb2 Latest Latest
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Published: Jun 26, 2023 License: MIT Imports: 19 Imported by: 0

Documentation

Index

Constants

View Source
const (
	CMD_READY = iota
	CMD_STARTTLS
	CMD_HELO
	CMD_EHLO
	CMD_AUTH_PLAIN
	CMD_AUTH_LOGIN
	CMD_AUTH_LOGIN_USER
	CMD_AUTH_LOGIN_PWD
	CMD_MAIL_FROM
	CMD_RCPT_TO
	CMD_DATA
	CMD_DATA_END
	CMD_QUIT
)
View Source
const (
	MSG_INIT            = "220.init"
	MSG_OK              = "250.ok"
	MSG_MAIL_OK         = "250"
	MSG_BYE             = "221"
	MSG_BAD_SYNTAX      = "500"
	MSG_COMMAND_HE_ERR  = "503"
	MSG_COMMAND_ERR     = "502"
	MSG_BAD_USER        = "505"
	MSG_BAD_OPEN_RELAY  = "505.open.relay"
	MSG_BAD_MAIL_ADDR   = "554"
	MSG_COMMAND_TM_ERR  = "421"
	MSG_COMMAND_TM_CTC  = "421.ctc"
	MSG_AUTH_LOGIN_USER = "334.user"
	MSG_AUTH_LOGIN_PWD  = "334.passwd"
	MSG_AUTH_OK         = "235"
	MSG_AUTH_FAIL       = "535"
	MSG_DATA            = "354"
	MSG_STARTTLS        = "220"
)

Variables

View Source
var GO_EOL = tools.GetGoEol()

Functions

func Delivery

func Delivery(addr string, from string, to string, msg []byte) error

Delivery of mail to external mail

func DeliveryDebug

func DeliveryDebug(args ...interface{})

func DnsQuery

func DnsQuery(domain string) (string, error)

func SendMail

func SendMail(addr string, a Auth, from string, to []string, msg []byte) error

SendMail connects to the server at addr, switches to TLS if possible, authenticates with the optional mechanism a if possible, and then sends an email from address from, to addresses to, with message msg. The addr must include a port, as in "mail.example.com:smtp".

The addresses in the to parameter are the SMTP RCPT addresses.

The msg parameter should be an RFC 822-style email with headers first, a blank line, and then the message body. The lines of msg should be CRLF terminated. The msg headers should usually include fields such as "From", "To", "Subject", and "Cc". Sending "Bcc" messages is accomplished by including an email address in the to parameter but not including it in the msg headers.

The SendMail function and the net/smtp package are low-level mechanisms and provide no support for DKIM signing, MIME attachments (see the mime/multipart package), or other mail functionality. Higher-level packages exist outside of the standard library.

func Start

func Start(port int)

func StartSSL

func StartSSL(port int)

Types

type Auth

type Auth interface {
	// Start begins an authentication with a server.
	// It returns the name of the authentication protocol
	// and optionally data to include in the initial AUTH message
	// sent to the server. It can return proto == "" to indicate
	// that the authentication should be skipped.
	// If it returns a non-nil error, the SMTP client aborts
	// the authentication attempt and closes the connection.
	Start(server *ServerInfo) (proto string, toServer []byte, err error)

	// Next continues the authentication. The server has just sent
	// the fromServer data. If more is true, the server expects a
	// response, which Next should return as toServer; otherwise
	// Next should return toServer == nil.
	// If Next returns a non-nil error, the SMTP client aborts
	// the authentication attempt and closes the connection.
	Next(fromServer []byte, more bool) (toServer []byte, err error)
}

Auth is implemented by an SMTP authentication mechanism.

func CRAMMD5Auth

func CRAMMD5Auth(username, secret string) Auth

CRAMMD5Auth returns an Auth that implements the CRAM-MD5 authentication mechanism as defined in RFC 2195. The returned Auth uses the given username and secret to authenticate to the server using the challenge-response mechanism.

func PlainAuth

func PlainAuth(identity, username, password, host string) Auth

PlainAuth returns an Auth that implements the PLAIN authentication mechanism as defined in RFC 4616. The returned Auth uses the given username and password to authenticate to host and act as identity. Usually identity should be the empty string, to act as username.

PlainAuth will only send the credentials if the connection is using TLS or is connected to localhost. Otherwise authentication will fail with an error, without sending the credentials.

type Client

type Client struct {
	// Text is the textproto.Conn used by the Client. It is exported to allow for
	// clients to add extensions.
	Text *textproto.Conn
	// contains filtered or unexported fields
}

A Client represents a client connection to an SMTP server.

func Dial

func Dial(addr string) (*Client, error)

Dial returns a new Client connected to an SMTP server at addr. The addr must include a port, as in "mail.example.com:smtp".

func NewClient

func NewClient(conn net.Conn, host string) (*Client, error)

NewClient returns a new Client using an existing connection and host as a server name to be used when authenticating.

func (*Client) Auth

func (c *Client) Auth(a Auth) error

Auth authenticates a client using the provided authentication mechanism. A failed authentication closes the connection. Only servers that advertise the AUTH extension support this function.

func (*Client) Close

func (c *Client) Close() error

Close closes the connection.

func (*Client) CmdExec

func (c *Client) CmdExec(expectCode int, format string, args ...interface{}) (int, string, error)

cmd is a convenience function that sends a command and returns the response

func (*Client) Data

func (c *Client) Data() (io.WriteCloser, error)

Data issues a DATA command to the server and returns a writer that can be used to write the mail headers and body. The caller should close the writer before calling any more methods on c. A call to Data must be preceded by one or more calls to Rcpt.

func (*Client) Extension

func (c *Client) Extension(ext string) (bool, string)

Extension reports whether an extension is support by the server. The extension name is case-insensitive. If the extension is supported, Extension also returns a string that contains any parameters the server specifies for the extension.

func (*Client) Hello

func (c *Client) Hello(localName string) error

Hello sends a HELO or EHLO to the server as the given host name. Calling this method is only necessary if the client needs control over the host name used. The client will introduce itself as "localhost" automatically otherwise. If Hello is called, it must be called before any of the other methods.

func (*Client) Mail

func (c *Client) Mail(from string) error

Mail issues a MAIL command to the server using the provided email address. If the server supports the 8BITMIME extension, Mail adds the BODY=8BITMIME parameter. If the server supports the SMTPUTF8 extension, Mail adds the SMTPUTF8 parameter. This initiates a mail transaction and is followed by one or more Rcpt calls.

func (*Client) Noop

func (c *Client) Noop() error

Noop sends the NOOP command to the server. It does nothing but check that the connection to the server is okay.

func (*Client) Quit

func (c *Client) Quit() error

Quit sends the QUIT command and closes the connection to the server.

func (*Client) Rcpt

func (c *Client) Rcpt(to string) error

Rcpt issues a RCPT command to the server using the provided email address. A call to Rcpt must be preceded by a call to Mail and may be followed by a Data call or another Rcpt call.

func (*Client) Reset

func (c *Client) Reset() error

Reset sends the RSET command to the server, aborting the current mail transaction.

func (*Client) StartTLS

func (c *Client) StartTLS(config *tls.Config) error

StartTLS sends the STARTTLS command and encrypts all further communication. Only servers that advertise the STARTTLS extension support this function.

func (*Client) TLSConnectionState

func (c *Client) TLSConnectionState() (state tls.ConnectionState, ok bool)

TLSConnectionState returns the client's TLS connection state. The return values are their zero values if StartTLS did not succeed.

func (*Client) Verify

func (c *Client) Verify(addr string) error

Verify checks the validity of an email address on the server. If Verify returns nil, the address is valid. A non-nil return does not necessarily indicate an invalid address. Many servers will not verify addresses for security reasons.

type Peer

type Peer struct {
	HeloName         string   // Server name used in HELO/EHLO command
	Username         string   // Username from authentication, if authenticated
	Password         string   // Password from authentication, if authenticated
	Protocol         Protocol // Protocol used, SMTP or ESMTP
	ServerName       string   // A copy of Server.Hostname
	Addr             net.Addr // Network address
	ReceivedMailAddr string   // Received Mail Address
}

Peer represents the client connecting to the server

type Protocol

type Protocol string

Protocol represents the protocol used in the SMTP session

const (
	// SMTP
	SMTP Protocol = "SMTP"

	// Extended SMTP
	ESMTP = "ESMTP"
)

type ServerInfo

type ServerInfo struct {
	Name string   // SMTP server name
	TLS  bool     // using TLS, with valid certificate for Name
	Auth []string // advertised authentication mechanisms
}

ServerInfo records information about an SMTP server.

type SmtpdServer

type SmtpdServer struct {
	Port int

	LinkSSL bool

	TLSConfig *tls.Config // Enable STARTTLS support.

	//global
	Domain string
	// contains filtered or unexported fields
}

func (*SmtpdServer) D

func (smtp *SmtpdServer) D(format string, args ...interface{})

func (*SmtpdServer) SetReadDeadline

func (smtp *SmtpdServer) SetReadDeadline(state int)

func (*SmtpdServer) StartPort

func (smtp *SmtpdServer) StartPort(port int)

func (*SmtpdServer) StartSSLPort

func (smtp *SmtpdServer) StartSSLPort(port int)

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