frameassembly 1.5.1

A DSL for creating custom .pcap/.pcapng captures and decompiling captures to .fasm for testing firewalls, IDS rules, SNMP traps, and pentesting.
Documentation 
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//! Session Initiation Protocol (SIP) (RFC 3261 / RFC 3262 (PRACK) / RFC 3428 (MESSAGE) / RFC 4566 (SDP)) Layer 7 wire packet builder.
//!
//! This module synthesizes deterministic on-the-wire Session Initiation Protocol (SIP) frames over UDP/TCP port 5060 (SIP) and TCP/TLS port 5061 (SIPS).
//! The wire encoder constructs a UTF-8 text signaling message starting with a Request-Line (`<METHOD> <URI> SIP/2.0\r\n` for `INVITE`, `ACK`, `BYE`, `CANCEL`, `REGISTER`, `OPTIONS`, `MESSAGE`) or Status-Line (`SIP/2.0 <STATUS> <REASON>\r\n` e.g. `100 Trying`, `180 Ringing`, `200 OK`, `401 Unauthorized`, `486 Busy Here`), followed by `Via:`, `From:`, `To:`, `Call-ID:`, `CSeq:`, `Contact:`, `Content-Type:`, `Content-Length:`, and optional `application/sdp` body. When optional fields in [`SipSpec`]
//! are omitted in the `.fasm` source, RFC-compliant default values are automatically populated.
//!
//! Canonical `.fasm` syntax:
//! `a -> b SIP [INVITE | BYE | CANCEL | METHOD <str>] [URI <str>] [STATUS <u16>] [REASON <str>] [FROM <str>] [TO <str>] [CALL_ID <str>] [CSEQ <u32>] [VIA <str>] [CONTACT <str>] [CONTENT_TYPE <str>] [BODY <str>] [TRANSPORT TCP]`

use crate::ast::*;
use crate::builders::WireContext;
use alloc::vec::Vec;

/// Builds an RFC 3261 SIP VoIP message string.
/// Syntax mapping: `SIP [INVITE | BYE | CANCEL | METHOD <str>] [URI <str>] [STATUS <u16>] [REASON <str>] [FROM <str>] [TO <str>] [CALL_ID <str>] [CSEQ <u32>] [VIA <str>] [CONTACT <str>] [CONTENT_TYPE <str>] [BODY <str>] [TRANSPORT TCP]`
#[doc(alias = "SIP")]
#[doc(alias = "VOIP")]
#[doc(alias = "RFC3261")]
#[doc(alias = "INVITE")]
#[doc(alias = "CALL_ID")]
#[doc(alias = "CSEQ")]
pub fn build_sip_payload(
    ctx: &WireContext,
    spec: &SipSpec,
    payload_bytes: &[u8],
) -> Vec<u8> {
    let mut out = String::new();
    let call_id = spec.call_id.unwrap_or("call123@pbx");
    let cseq = spec.cseq.unwrap_or(1);
    let cseq_method = spec.method.unwrap_or("INVITE");

    if let Some(status) = spec.status {
        let reason = spec.reason.unwrap_or("OK");
        out.push_str(&format!("SIP/2.0 {} {}\r\n", status, reason));
        if let Some(via) = spec.via {
            out.push_str(&format!("Via: {}\r\n", via));
        }
        if let Some(from) = spec.from {
            out.push_str(&format!("From: {}\r\n", from));
        }
        if let Some(to) = spec.to {
            out.push_str(&format!("To: {}\r\n", to));
        }
        out.push_str(&format!(
            "Call-ID: {}\r\nCSeq: {} {}\r\n",
            call_id, cseq, cseq_method
        ));
        if let Some(contact) = spec.contact {
            if contact.starts_with('<') {
                out.push_str(&format!("Contact: {}\r\n", contact));
            } else {
                out.push_str(&format!("Contact: <{}>\r\n", contact));
            }
        }
        if let Some(ct) = spec.content_type {
            out.push_str(&format!("Content-Type: {}\r\n", ct));
        } else if !payload_bytes.is_empty() {
            out.push_str("Content-Type: application/sdp\r\n");
        }
        if let Some(body) = spec.body {
            out.push_str(&format!("Content-Length: {}\r\n\r\n{}", body.len(), body));
        } else if !payload_bytes.is_empty() {
            out.push_str(&format!("Content-Length: {}\r\n\r\n", payload_bytes.len()));
            let mut bytes = out.into_bytes();
            bytes.extend_from_slice(payload_bytes);
            return bytes;
        } else {
            out.push_str("Content-Length: 0\r\n\r\n");
        }
    } else {
        let method = spec.method.unwrap_or("INVITE");
        let uri = spec.uri.unwrap_or("sip:service@pbx.local");
        let from = spec.from.unwrap_or("sip:alice@pbx");
        let to = spec.to.unwrap_or("sip:bob@pbx");
        let via = spec
            .via
            .map(|v| v.to_string())
            .unwrap_or_else(|| format!("SIP/2.0/UDP {}:5060;branch=z9hG4bK-1", ctx.src_ip));

        out.push_str(&format!(
            "{} {} SIP/2.0\r\nVia: {}\r\nFrom: <{}>;tag=1\r\nTo: <{}>\r\nCall-ID: {}\r\nCSeq: {} {}\r\n",
            method, uri, via, from, to, call_id, cseq, method
        ));
        if let Some(contact) = spec.contact {
            if contact.starts_with('<') {
                out.push_str(&format!("Contact: {}\r\n", contact));
            } else {
                out.push_str(&format!("Contact: <{}>\r\n", contact));
            }
        }
        if let Some(ct) = spec.content_type {
            out.push_str(&format!("Content-Type: {}\r\n", ct));
        } else if !payload_bytes.is_empty() {
            out.push_str("Content-Type: application/sdp\r\n");
        }
        if let Some(body) = spec.body {
            out.push_str(&format!("Content-Length: {}\r\n\r\n{}", body.len(), body));
        } else if !payload_bytes.is_empty() {
            out.push_str(&format!("Content-Length: {}\r\n\r\n", payload_bytes.len()));
            let mut bytes = out.into_bytes();
            bytes.extend_from_slice(payload_bytes);
            return bytes;
        } else {
            out.push_str("Content-Length: 0\r\n\r\n");
        }
    }

    out.into_bytes()
}