Trait ServerBuilderExt

pub trait ServerBuilderExt {
    // Required methods
    fn server(self, product: impl Into<String>) -> Self;
    fn server_products(self, products: Vec<impl Into<String>>) -> Self;
}

Server header builder

This module provides builder methods for the Server header in SIP messages.

SIP Server Header Overview

The Server header is defined in RFC 3261 as part of the core SIP protocol. It contains information about the software implementation used by the UAS (User Agent Server) or server generating the response. This header helps identify the server software for troubleshooting, statistics, and compatibility handling.

Purpose of Server Header

The Server header serves several important purposes in SIP:

1. It identifies the server software responding to requests
2. It helps with troubleshooting interoperability issues
3. It provides information for network analytics and statistics
4. It allows clients to implement workarounds for known server behaviors

Format and Conventions

The Server header typically follows these formatting conventions:

• Product/version identifiers (e.g., “SIP-Server/1.0”)
• Platform information in parentheses (e.g., “(Linux x86_64)”)
• Multiple components separated by spaces
• Order from general to specific (platform, server, modules)

A comprehensive Server header might look like: SIPProxy/5.2 (Debian; Linux x86_64) OpenSIPS/3.1

Comparison with User-Agent Header

The Server header is analogous to the User-Agent header:

• Server: Used in responses to identify the responding server software
• User-Agent: Used in requests to identify the client software

Security Considerations

When implementing Server headers, consider:

• The header may reveal implementation details that could be exploited
• Version information might expose vulnerability windows
• Some deployments may choose to minimize information disclosure
• In secure environments, generic identifiers may be preferred over detailed information

Examples

Basic SIP Proxy Identification

use rvoip_sip_core::prelude::*;
use rvoip_sip_core::builder::{SimpleResponseBuilder, headers::ServerBuilderExt};

// Scenario: SIP proxy responding to an OPTIONS request

// Create a 200 OK response with Server identification
let response = SimpleResponseBuilder::new(StatusCode::Ok, None)
    .from("ProxyServer", "sip:proxy.example.com", None)
    .to("Client", "sip:client@example.org", Some("abc123"))
    // Identify the server software
    .server("MyProxyServer/2.3")
    .build();

// The client can identify which server implementation handled the request
// and potentially adjust behavior based on known server capabilities

Detailed Server Information

use rvoip_sip_core::prelude::*;
use rvoip_sip_core::builder::{SimpleResponseBuilder, headers::ServerBuilderExt};

// Scenario: SIP registrar with comprehensive server information

// Create a REGISTER 200 OK with detailed server information
let response = SimpleResponseBuilder::new(StatusCode::Ok, None)
    .from("User", "sip:user@example.com", Some("reg123"))
    .to("User", "sip:user@example.com", None)
    .contact("<sip:user@203.0.113.1:5060>", Some("7200"))
    // Add detailed server information
    .server_products(vec![
        "ExampleSIPServer/4.2.1",    // Product name and version
        "(Ubuntu 20.04 LTS)",        // OS information
        "Kamailio/5.4.3",            // SIP server software
        "TLS/1.3"                    // Security information
    ])
    .build();

// Administrators can use this detailed information for
// troubleshooting and interoperability analysis

Enterprise SBC with Minimal Identification

use rvoip_sip_core::prelude::*;
use rvoip_sip_core::builder::{SimpleResponseBuilder, headers::ServerBuilderExt};

// Scenario: Session Border Controller with security considerations

// Create a 403 Forbidden response with minimal server information
let response = SimpleResponseBuilder::new(StatusCode::Forbidden, Some("Authentication Failed"))
    .from("SBC", "sip:edge.enterprise.example", None)
    .to("External", "sip:external@example.org", Some("ext789"))
    // Use generic identifier to avoid revealing implementation details
    .server("EnterpriseSessionBorderController")
    .build();

// Minimal identification that doesn't reveal version information
// which could be used by attackers to target known vulnerabilities

Required Methods

fn server(self, product: impl Into<String>) -> Self

Add a Server header with a single product token

This method adds a Server header with a single product identifier, which is typically in the format “ProductName/VersionNumber”.

Parameters

• product - The product identifier string, typically in Product/Version format

Returns

• Self - The builder with the Server header added

Examples

use rvoip_sip_core::prelude::*;
use rvoip_sip_core::builder::{SimpleResponseBuilder, headers::ServerBuilderExt};

// Basic 200 OK response from a SIP registrar
let response = SimpleResponseBuilder::new(StatusCode::Ok, None)
    .from("Registrar", "sip:registrar.example.com", None)
    .to("User", "sip:user@example.org", Some("reg456"))
    // Identify as version 3.1 of the registrar software
    .server("SIPRegistrar/3.1")
    .build();

// The client knows this is version 3.1 of the SIP registrar

fn server_products(self, products: Vec<impl Into<String>>) -> Self

Add a Server header with multiple product tokens

This method adds a Server header with multiple product identifiers, which allows for more detailed server information including product names, versions, platform details, and additional components.

Parameters

• products - A vector of product identifier strings and other components

Returns

• Self - The builder with the Server header containing all components

Examples

use rvoip_sip_core::prelude::*;
use rvoip_sip_core::builder::{SimpleResponseBuilder, headers::ServerBuilderExt};

// Create a 486 Busy Here response with comprehensive server information
let response = SimpleResponseBuilder::new(StatusCode::BusyHere, None)
    .from("PBX", "sip:pbx.example.com", None)
    .to("Caller", "sip:caller@example.org", Some("call123"))
    // Add detailed server stack information
    .server_products(vec![
        "CompanyPBX/5.1.2",             // Main product
        "(CentOS 7; x86_64)",           // OS details
        "FreeSWITCH/1.10.7",            // SIP server platform
        "mod_sofia/1.0.0",              // SIP module
        "mod_conference/1.7.0"          // Conference module
    ])
    .build();

// This provides comprehensive information for troubleshooting
// and feature compatibility assessment

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<T> ServerBuilderExt for T

where T: HeaderSetter,