smpp

Documentation

Overview

Package smpp implements fingerprinting for the SMPP (Short Message Peer-to-Peer) protocol.

SMPP is a telecommunications protocol used for exchanging SMS messages between SMS gateways and message centers. Detection uses a two-phase approach with fallback:

Phase 1a: Detection via enquire_link (preferred)

• Send enquire_link PDU (command_id 0x00000015)
• Validate enquire_link_resp (command_id 0x80000015)
• If successful, proceed to enrichment

Phase 1b: Fallback detection via bind_transceiver

• Some servers only respond to enquire_link when already bound (non-standard)
• If enquire_link fails, send bind_transceiver with dummy credentials
• ANY valid SMPP response confirms protocol (including auth errors, generic_nack)
• Cache response to avoid resending during enrichment

Phase 2: Enrichment via bind_transceiver

• Use cached response from Phase 1b if available
• Otherwise, attempt bind_transceiver with dummy credentials
• Extract system_id from bind_transceiver_resp (even on auth error)
• Parse sc_interface_version TLV (tag 0x0210) for protocol version
• Identify vendor from system_id patterns

PDU Structure (16-byte header):

Offset  Size  Field            Description
0       4     command_length   Total PDU length (big-endian)
4       4     command_id       Operation identifier (big-endian)
8       4     command_status   Result code (big-endian)
12      4     sequence_number  Request/response correlation (big-endian)

Key Command IDs:

• enquire_link: 0x00000015
• enquire_link_resp: 0x80000015
• bind_transceiver: 0x00000009
• bind_transceiver_resp: 0x80000009
• generic_nack: 0x80000000

Error codes confirming SMPP (even on auth failure):

• ESME_RINVPASWD (0x0E): Invalid password
• ESME_RINVSYSID (0x0F): Invalid system_id
• ESME_RALYBND (0x05): Already bound

Index

• Constants
• type SMPPPlugin
  • func (p *SMPPPlugin) Name() string
  • func (p *SMPPPlugin) PortPriority(port uint16) bool
  • func (p *SMPPPlugin) Priority() int
  • func (p *SMPPPlugin) Run(conn net.Conn, timeout time.Duration, target plugins.Target) (*plugins.Service, error)
  • func (p *SMPPPlugin) Type() plugins.Protocol
• type VendorInfo

Constants

const (
	SMPP                      = "smpp"
	MIN_RESPONSE_SIZE         = 16
	PDU_HEADER_SIZE           = 16
	CMD_ENQUIRE_LINK          = 0x00000015
	CMD_ENQUIRE_LINK_RESP     = 0x80000015
	CMD_BIND_TRANSCEIVER      = 0x00000009
	CMD_BIND_TRANSCEIVER_RESP = 0x80000009
	CMD_GENERIC_NACK          = 0x80000000
	STATUS_OK                 = 0x00000000
	TLV_SC_INTERFACE_VERSION  = 0x0210
)

Types

type SMPPPlugin

type SMPPPlugin struct{}

func (*SMPPPlugin) Name

func (p *SMPPPlugin) Name() string

func (*SMPPPlugin) PortPriority

func (p *SMPPPlugin) PortPriority(port uint16) bool

func (*SMPPPlugin) Priority

func (p *SMPPPlugin) Priority() int

func (*SMPPPlugin) Run

func (p *SMPPPlugin) Run(conn net.Conn, timeout time.Duration, target plugins.Target) (*plugins.Service, error)

func (*SMPPPlugin) Type

func (p *SMPPPlugin) Type() plugins.Protocol

type VendorInfo

type VendorInfo struct {
	Vendor  string
	Product string
}

VendorInfo holds detected vendor and product information