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feat: implement IGMP parsing
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@SkuldNorniern
SkuldNorniern committed Jan 21, 2025
1 parent 371112d commit f2534b2
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314 changes: 314 additions & 0 deletions src/net/parser/raw/protocols/igmp.rs
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use crate::net::parser::raw::protocols::ProtocolParser;
use crate::net::parser::raw::RawProtocolHeader;
use std::net::{IpAddr, Ipv4Addr};

pub struct IgmpParser;

// IGMP message types with their RFC-specified values
const MEMBERSHIP_QUERY: u8 = 0x11; // Query message for all versions
const IGMPV1_MEMBERSHIP_REPORT: u8 = 0x12; // IGMPv1 report message
const IGMPV2_MEMBERSHIP_REPORT: u8 = 0x16; // IGMPv2 report message
const IGMPV3_MEMBERSHIP_REPORT: u8 = 0x22; // IGMPv3 report message
const LEAVE_GROUP: u8 = 0x17; // IGMPv2/v3 leave message

impl IgmpParser {
// IGMPv2 Message Format (RFC 2236)
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Type | Max Resp Time | Checksum |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Group Address |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//
// Type (8 bits):
// - 0x11: Membership Query
// - 0x12: IGMPv1 Membership Report
// - 0x16: IGMPv2 Membership Report
// - 0x17: Leave Group
//
// Max Response Time (8 bits):
// - In units of 0.1 seconds
// - Used only in Membership Query messages
// - Set to 0 in other messages
//
// Checksum (16 bits):
// - 16-bit one's complement of the one's complement sum
//
// Group Address (32 bits):
// - Multicast group address being queried/reported
// - Set to 0 in General Query messages

// IGMPv3 Query Message Format (RFC 3376)
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Type = 0x11 | Max Resp Code | Checksum |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Group Address |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Resv |S| QRV | QQIC | Number of Sources (N) |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | Source Address [1] |
// +- -+
// | Source Address [2] |
// +- . -+
// | Source Address [N] |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//
// S Flag (1 bit):
// - Suppress Router-Side Processing flag
//
// QRV (3 bits):
// - Querier's Robustness Variable
//
// QQIC (8 bits):
// - Querier's Query Interval Code
//
// Number of Sources (16 bits):
// - Number of source addresses present
//
// Source Addresses:
// - List of N IPv4 source addresses

// Destination addresses for different message types:
// General Query: 224.0.0.1 (All Systems)
// Group-Specific Query: The group being queried
// IGMPv1/v2/v3 Membership Report: The group being reported
// Leave Group: 224.0.0.2 (All Routers)
// IGMPv3 Membership Report: 224.0.0.22 (IGMPv3-capable multicast routers)

fn get_destination_addr(igmp_type: u8) -> Option<IpAddr> {
match igmp_type {
MEMBERSHIP_QUERY => Some(IpAddr::V4(Ipv4Addr::new(224, 0, 0, 1))), // All Systems
LEAVE_GROUP => Some(IpAddr::V4(Ipv4Addr::new(224, 0, 0, 2))), // All Routers
IGMPV3_MEMBERSHIP_REPORT => Some(IpAddr::V4(Ipv4Addr::new(224, 0, 0, 22))), // IGMPv3 Routers
_ => None,
}
}

fn parse_v3_query(payload: &[u8]) -> Option<RawProtocolHeader> {
if payload.len() < 12 {
return None;
}

let max_resp_code = payload[1];
let group_addr = if payload.len() >= 8 {
Some(IpAddr::V4(Ipv4Addr::new(
payload[4], payload[5], payload[6], payload[7],
)))
} else {
None
};

let flags = payload[8];
let qrv = flags & 0x07;
let qqic = payload[9];
let num_sources = u16::from_be_bytes([payload[10], payload[11]]);

let expected_len = 12 + (num_sources as usize * 4);
if payload.len() < expected_len {
return None;
}

let inner_payload = if num_sources > 0 {
Some(payload[12..expected_len].to_vec())
} else {
None
};

Some(
RawProtocolHeader::new(
None,
group_addr,
MEMBERSHIP_QUERY as u16,
max_resp_code as u16,
Self::protocol_number(),
payload.len() as u16,
inner_payload,
)
.with_raw_packet(payload.to_vec())
.with_flags(flags)
.with_version(3)
.with_qrv(qrv)
.with_qqic(qqic),
)
}
}

impl ProtocolParser for IgmpParser {
fn protocol_number() -> u8 {
2
}

fn parse_packet(payload: &[u8], _protocol_number: u8) -> Option<RawProtocolHeader> {
if payload.len() < 8 {
return None;
}

let igmp_type = payload[0];
let max_resp_time = payload[1];
let group_addr = if payload.len() >= 8 {
Some(IpAddr::V4(Ipv4Addr::new(
payload[4], payload[5], payload[6], payload[7],
)))
} else {
None
};

if igmp_type == MEMBERSHIP_QUERY && payload.len() >= 12 {
return Self::parse_v3_query(payload);
}

let version = match igmp_type {
IGMPV1_MEMBERSHIP_REPORT => 1,
IGMPV2_MEMBERSHIP_REPORT | LEAVE_GROUP => 2,
IGMPV3_MEMBERSHIP_REPORT => 3,
MEMBERSHIP_QUERY => {
if payload.len() >= 12 {
3
} else {
2
}
}
_ => 2,
};

let inner_payload = if payload.len() > 8 {
Some(payload[8..].to_vec())
} else {
None
};

Some(
RawProtocolHeader::new(
None,
Self::get_destination_addr(igmp_type).or(group_addr),
igmp_type as u16,
max_resp_time as u16,
Self::protocol_number(),
payload.len() as u16,
inner_payload,
)
.with_raw_packet(payload.to_vec())
.with_flags(igmp_type)
.with_version(version),
)
}
}

#[cfg(test)]
mod tests {
use super::*;

#[test]
fn test_igmp_v1_membership_report() {
let payload = [
IGMPV1_MEMBERSHIP_REPORT, // Type
0, // Unused
0x00,
0x00, // Checksum (not validated)
239,
1,
2,
3, // Group Address
];

let result = IgmpParser::parse_packet(&payload, IgmpParser::protocol_number());
assert!(result.is_some());

let header = result.unwrap();
assert_eq!(header.version.unwrap(), 1);
assert_eq!(header.flags.unwrap(), IGMPV1_MEMBERSHIP_REPORT);
assert!(header.dst_ip.is_some());
}

#[test]
fn test_igmp_v2_membership_query() {
let payload = [
MEMBERSHIP_QUERY, // Type
100, // Max Response Time (10 seconds)
0x00,
0x00, // Checksum (not validated)
224,
0,
0,
1, // Group Address
];

let result = IgmpParser::parse_packet(&payload, IgmpParser::protocol_number());
assert!(result.is_some());

let header = result.unwrap();
assert_eq!(header.src_port, MEMBERSHIP_QUERY as u16);
assert_eq!(header.dst_port, 100); // Max Response Time
assert_eq!(header.version.unwrap(), 2);
assert_eq!(header.dst_ip.unwrap().to_string(), "224.0.0.1");
}

#[test]
fn test_igmp_v3_group_specific_query() {
let payload = [
MEMBERSHIP_QUERY, // Type
100, // Max Response Code
0x00,
0x00, // Checksum
239,
1,
2,
3, // Group Address (specific group)
0x02, // Resv|S|QRV (QRV=2)
0x7D, // QQIC
0x00,
0x00, // Number of Sources (0)
];

let result = IgmpParser::parse_packet(&payload, IgmpParser::protocol_number());
assert!(result.is_some());

let header = result.unwrap();
assert_eq!(header.version.unwrap(), 3);
assert_eq!(header.qrv.unwrap(), 2);
assert_eq!(header.qqic.unwrap(), 0x7D);
assert!(header.dst_ip.is_some());
}

#[test]
fn test_igmp_v3_source_specific_query() {
let payload = [
MEMBERSHIP_QUERY, // Type
100, // Max Response Code
0x00,
0x00, // Checksum
239,
1,
2,
3, // Group Address
0x02, // Resv|S|QRV (QRV=2)
0x7D, // QQIC
0x00,
0x01, // Number of Sources (1)
10,
0,
0,
1, // Source Address 1
];

let result = IgmpParser::parse_packet(&payload, IgmpParser::protocol_number());
assert!(result.is_some());

let header = result.unwrap();
assert_eq!(header.version.unwrap(), 3);
assert_eq!(header.qrv.unwrap(), 2);
assert!(header.payload.is_some());
assert_eq!(header.payload.unwrap().len(), 4); // 1 source address
}

#[test]
fn test_igmp_invalid_length() {
let payload = [
MEMBERSHIP_QUERY, // Type
100, // Max Response Time
0x00, // Incomplete packet
];

let result = IgmpParser::parse_packet(&payload, IgmpParser::protocol_number());
assert!(result.is_none());
}
}

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