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use crate::error::ParserErrorKind;
use bgp_models::bgp::BgpMessage;
use bgp_models::mrt::bgp4mp::{Bgp4Mp, Bgp4MpMessage, Bgp4MpStateChange, Bgp4MpType, BgpState};
use bgp_models::network::{Afi, Asn, AsnLength};
use num_traits::FromPrimitive;
use crate::parser::bgp::messages::parse_bgp_message;
use crate::parser::DataBytes;
pub fn parse_bgp4mp(sub_type: u16, input: &mut DataBytes) -> Result<Bgp4Mp, ParserErrorKind> {
let bgp4mp_type: Bgp4MpType = match Bgp4MpType::from_u16(sub_type) {
Some(t) => t,
None => {return Err(ParserErrorKind::ParseError(format!("cannot parse bgp4mp subtype: {}", sub_type)))}
};
let msg: Bgp4Mp = match bgp4mp_type {
Bgp4MpType::Bgp4MpStateChange => {
Bgp4Mp::Bgp4MpStateChange(parse_bgp4mp_state_change(input, AsnLength::Bits16, &bgp4mp_type)?)
}
Bgp4MpType::Bgp4MpStateChangeAs4 => {
Bgp4Mp::Bgp4MpStateChangeAs4(parse_bgp4mp_state_change(input, AsnLength::Bits32, &bgp4mp_type)?)
}
Bgp4MpType::Bgp4MpMessage|Bgp4MpType::Bgp4MpMessageLocal => {
Bgp4Mp::Bgp4MpMessage(parse_bgp4mp_message(input, false, AsnLength::Bits16, &bgp4mp_type)?)
}
Bgp4MpType::Bgp4MpMessageAs4 | Bgp4MpType::Bgp4MpMessageAs4Local => {
Bgp4Mp::Bgp4MpMessage(parse_bgp4mp_message(input, false, AsnLength::Bits32, &bgp4mp_type)?)
}
Bgp4MpType::Bgp4MpMessageAddpath| Bgp4MpType::Bgp4MpMessageLocalAddpath => {
Bgp4Mp::Bgp4MpMessage(parse_bgp4mp_message(input, true, AsnLength::Bits16, &bgp4mp_type)?)
}
Bgp4MpType::Bgp4MpMessageAs4Addpath | Bgp4MpType::Bgp4MpMessageLocalAs4Addpath => {
Bgp4Mp::Bgp4MpMessage(parse_bgp4mp_message(input, true, AsnLength::Bits32, &bgp4mp_type)?)
}
};
Ok(msg)
}
fn total_should_read(afi: &Afi, asn_len: &AsnLength, total_size: usize) -> usize {
let ip_size = match afi{
Afi::Ipv4 => { 4 * 2}
Afi::Ipv6 => { 16 * 2}
};
let asn_size = match asn_len {
AsnLength::Bits16 => {2 * 2}
AsnLength::Bits32 => {2 * 4}
};
total_size - asn_size - 2 - 2 - ip_size
}
pub fn parse_bgp4mp_message(input: &mut DataBytes, add_path: bool, asn_len: AsnLength, msg_type: &Bgp4MpType) -> Result<Bgp4MpMessage, ParserErrorKind> {
let total_size = input.total;
let peer_asn: Asn = input.read_asn(&asn_len)?;
let local_asn: Asn = input.read_asn(&asn_len)?;
let interface_index: u16 = input.read_16b()?;
let afi: Afi = input.read_afi()?;
let peer_ip = input.read_address(&afi)?;
let local_ip = input.read_address(&afi)?;
let should_read = total_should_read(&afi, &asn_len, total_size);
let bgp_message: BgpMessage = parse_bgp_message(input,add_path, &afi, &asn_len, should_read)?;
Ok(Bgp4MpMessage{
msg_type: msg_type.clone(),
peer_asn,
local_asn,
interface_index,
afi,
peer_ip,
local_ip,
bgp_message,
})
}
pub fn parse_bgp4mp_state_change(input: &mut DataBytes, asn_len: AsnLength, msg_type: &Bgp4MpType) -> Result<Bgp4MpStateChange, ParserErrorKind> {
let peer_asn: Asn = input.read_asn(&asn_len)?;
let local_asn: Asn = input.read_asn(&asn_len)?;
let interface_index: u16 = input.read_16b()?;
let address_family: Afi = input.read_afi()?;
let peer_addr = input.read_address(&address_family)?;
let local_addr = input.read_address(&address_family)?;
let old_state = match BgpState::from_u16(input.read_16b()?){
Some(t) => t,
None => {return Err(ParserErrorKind::ParseError(format!("cannot parse bgp4mp old_state")))}
};
let new_state = match BgpState::from_u16(input.read_16b()?){
Some(t) => t,
None => {return Err(ParserErrorKind::ParseError(format!("cannot parse bgp4mp new_state")))}
};
Ok(
Bgp4MpStateChange{
msg_type: msg_type.clone(),
peer_asn,
local_asn,
interface_index,
address_family,
peer_addr,
local_addr,
old_state,
new_state
}
)
}
