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refactor: extract answer_hostname_question from handle_query #511

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keepsimple1 merged 2 commits into from
Sep 21, 2026
Merged

refactor: extract answer_hostname_question from handle_query #511

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refactor: extract answer_hostname_question from handle_query
keepsimple1 Sep 21, 2026
89ed9ee
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keepsimple1 Sep 21, 2026
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184 changes: 105 additions & 79 deletions src/service_daemon.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -35,9 +35,9 @@ use crate::{
dns_cache::{DnsCache, IpType},
dns_parser::{
ip_address_rr_type, max_pkt_absolute, DnsAddress, DnsEntryExt, DnsIncoming, DnsNSec,
DnsOutgoing, DnsPointer, DnsRecordBox, DnsRecordExt, DnsSrv, DnsTxt, InterfaceId, RRType,
ScopedIp, CLASS_CACHE_FLUSH, CLASS_IN, FLAGS_AA, FLAGS_QR_QUERY, FLAGS_QR_RESPONSE,
MAX_PKT_ABSOLUTE_IPV6, MAX_PKT_DEFAULT,
DnsOutgoing, DnsPointer, DnsQuestion, DnsRecordBox, DnsRecordExt, DnsSrv, DnsTxt,
InterfaceId, RRType, ScopedIp, CLASS_CACHE_FLUSH, CLASS_IN, FLAGS_AA, FLAGS_QR_QUERY,
FLAGS_QR_RESPONSE, MAX_PKT_ABSOLUTE_IPV6, MAX_PKT_DEFAULT,
},
error::{e_fmt, Error, Result},
service_info::{
Expand Down Expand Up @@ -3497,82 +3497,14 @@ impl Zeroconf {
qtype,
RRType::A | RRType::AAAA | RRType::ANY | RRType::SVCB | RRType::HTTPS
) {
let mut hostname = None;
let mut host_ttl = u32::MAX;
let mut has_ipv4 = false;
let mut has_ipv6 = false;
for service in self.my_services.values() {
if service.get_status(if_index) != ServiceStatus::Announced {
continue;
}

let service_hostname = dns_registry.resolve_name(service.get_hostname());

if service_hostname.to_lowercase() == question.entry_name().to_lowercase() {
let ipv4 = service.get_addrs_on_my_intf_v4(intf);
let ipv6 = service.get_addrs_on_my_intf_v6(intf);
if ipv4.is_empty() && ipv6.is_empty() {
continue;
}
hostname = Some(service_hostname);
host_ttl = host_ttl.min(service.get_host_ttl());
has_ipv4 |= !ipv4.is_empty();
has_ipv6 |= !ipv6.is_empty();
// Pick addresses based on the question type, not the
// socket family. RFC 6762 doesn't require A queries
// to come over IPv4 transport — Android's getaddrinfo
// routinely sends both A and AAAA queries over its
// preferred IPv6 mDNS socket and expects A records
// to be answered with v4 addresses.
let mut intf_addrs: Vec<IpAddr> = Vec::new();
if qtype == RRType::A || qtype == RRType::ANY {
intf_addrs.extend(ipv4);
}
if qtype == RRType::AAAA || qtype == RRType::ANY {
intf_addrs.extend(ipv6);
}
for address in intf_addrs {
out.add_answer(
&msg,
DnsAddress::new(
service_hostname,
ip_address_rr_type(&address),
CLASS_IN | CLASS_CACHE_FLUSH,
service.get_host_ttl(),
address,
intf.into(),
),
);
}
}
}
let missing = match qtype {
RRType::A => !has_ipv4,
RRType::AAAA => !has_ipv6,
RRType::SVCB | RRType::HTTPS => true,
_ => false,
};
if let Some(hostname) = hostname.filter(|_| missing) {
// RFC 6762 section 6.1: explicitly deny absent records
// only for a hostname we own on this interface. Combine
// all announced services sharing the hostname, so one
// registration cannot deny another's address family.
let bitmap = if has_ipv6 {
vec![if has_ipv4 { 0x40 } else { 0 }, 0, 0, 0x08]
} else {
vec![0x40]
};
out.add_answer(
&msg,
DnsNSec::new(
hostname,
CLASS_IN | CLASS_CACHE_FLUSH,
host_ttl,
hostname.to_string(),
bitmap,
),
);
}
answer_hostname_question(
&self.my_services,
intf,
question,
dns_registry,
&mut out,
&msg,
);
}

let query_name = q_name.to_lowercase();
Expand Down Expand Up @@ -4426,6 +4358,100 @@ fn add_answer_of_service(
}
}

/// Answers a query for a hostname we own: A/AAAA (address records), SVCB/HTTPS
/// (service-binding records), or ANY.
///
/// Adds the A/AAAA records held on `intf` for every announced service whose
/// hostname matches the question. If the queried address family is absent, adds
/// NSEC (negative) answer instead. SVCB/HTTPS always get the NSEC answer.
fn answer_hostname_question(
services: &HashMap<String, ServiceInfo>,
intf: &MyIntf,
question: &DnsQuestion,
dns_registry: &DnsRegistry,
out: &mut DnsOutgoing,
msg: &DnsIncoming,
) {
let if_index = intf.index;
let qtype = question.entry_type();
let mut hostname = None;
let mut host_ttl = u32::MAX;
let mut has_ipv4 = false;
let mut has_ipv6 = false;
for service in services.values() {
if service.get_status(if_index) != ServiceStatus::Announced {
continue;
}

let service_hostname = dns_registry.resolve_name(service.get_hostname());

if service_hostname.to_lowercase() == question.entry_name().to_lowercase() {
let ipv4 = service.get_addrs_on_my_intf_v4(intf);
let ipv6 = service.get_addrs_on_my_intf_v6(intf);
if ipv4.is_empty() && ipv6.is_empty() {
continue;
}
hostname = Some(service_hostname);
host_ttl = host_ttl.min(service.get_host_ttl());
has_ipv4 |= !ipv4.is_empty();
has_ipv6 |= !ipv6.is_empty();
// Pick addresses based on the question type, not the
// socket family. RFC 6762 doesn't require A queries
// to come over IPv4 transport — Android's getaddrinfo
// routinely sends both A and AAAA queries over its
// preferred IPv6 mDNS socket and expects A records
// to be answered with v4 addresses.
let mut intf_addrs: Vec<IpAddr> = Vec::new();
if qtype == RRType::A || qtype == RRType::ANY {
intf_addrs.extend(ipv4);
}
if qtype == RRType::AAAA || qtype == RRType::ANY {
intf_addrs.extend(ipv6);
}
for address in intf_addrs {
out.add_answer(
msg,
DnsAddress::new(
service_hostname,
ip_address_rr_type(&address),
CLASS_IN | CLASS_CACHE_FLUSH,
service.get_host_ttl(),
address,
intf.into(),
),
);
}
}
}
let missing = match qtype {
RRType::A => !has_ipv4,
RRType::AAAA => !has_ipv6,
RRType::SVCB | RRType::HTTPS => true,
_ => false,
};
if let Some(hostname) = hostname.filter(|_| missing) {
// RFC 6762 section 6.1: explicitly deny absent records
// only for a hostname we own on this interface. Combine
// all announced services sharing the hostname, so one
// registration cannot deny another's address family.
let bitmap = if has_ipv6 {
vec![if has_ipv4 { 0x40 } else { 0 }, 0, 0, 0x08]
} else {
vec![0x40]
};
out.add_answer(
msg,
DnsNSec::new(
hostname,
CLASS_IN | CLASS_CACHE_FLUSH,
host_ttl,
hostname.to_string(),
bitmap,
),
);
}
}

/// All possible events sent to the client from the daemon
/// regarding service discovery.
#[derive(Clone, Debug)]
Expand Down