c/ooni-probe-cli
Watch
1
0
Fork
You've already forked ooni-probe-cli
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

feat: save CNAME into archival data format (#877)

Browse source 
* feat: save CNAME into archival data format

When a DNSResponse contains a non-empty CNAME, we include it
into the related list of answers.

Closes https://github.com/ooni/probe/issues/2227

* doc: add design note

While there, make code more compact and robust to a case where
we're going to extract additional answers.

* doc: document the expected growth of extraction function

Based on feedback by @DecFox
This commit is contained in:
Simone Basso 2022-08-23 15:13:37 +02:00 • committed by GitHub
commit 60b7d1f87b
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
2 changed files with 205 additions and 44 deletions
Download patch file Download diff file Expand all files Collapse all files

36
internal/measurexlite/dns.go
View file

@ -114,7 +114,7 @@ type DNSNetworkAddresser interface {
func NewArchivalDNSLookupResultFromRoundTrip(index int64, started time.Duration, reso DNSNetworkAddresser, query model.DNSQuery,
response model.DNSResponse, addrs []string, err error, finished time.Duration) *model.ArchivalDNSLookupResult {
return &model.ArchivalDNSLookupResult{
Answers: archivalAnswersFromAddrs(addrs),
Answers: newArchivalDNSAnswers(addrs, response),
Engine: reso.Network(),
Failure: tracex.NewFailure(err),
Hostname: query.Domain(),
@ -125,8 +125,16 @@ func NewArchivalDNSLookupResultFromRoundTrip(index int64, started time.Duration,
}
}
// archivalAnswersFromAddrs generates model.ArchivalDNSAnswer from an array of addresses
func archivalAnswersFromAddrs(addrs []string) (out []model.ArchivalDNSAnswer) {
// newArchivalDNSAnswers generates []model.ArchivalDNSAnswer from [addrs] and [resp].
func newArchivalDNSAnswers(addrs []string, resp model.DNSResponse) (out []model.ArchivalDNSAnswer) {
// Design note: in principle we might want to extract everything from the
// response but, when we're called by netxlite, netxlite has already extracted
// the addresses to return them to the caller, so I think it's fine to keep
// this extraction code as such rather than suppressing passing the addrs from
// netxlite. Also, a wrong IP address is a bug because netxlite should not
// return invalid IP addresses from its resolvers, so we want to know about that.
// Include IP addresses extracted by netxlite
for _, addr := range addrs {
ipv6, err := netxlite.IsIPv6(addr)
if err != nil {
@ -142,6 +150,7 @@ func archivalAnswersFromAddrs(addrs []string) (out []model.ArchivalDNSAnswer) {
AnswerType: "A",
Hostname: "",
IPv4: addr,
IPv6: "",
TTL: nil,
})
case true:
@ -150,11 +159,32 @@ func archivalAnswersFromAddrs(addrs []string) (out []model.ArchivalDNSAnswer) {
ASOrgName: org,
AnswerType: "AAAA",
Hostname: "",
IPv4: "",
IPv6: addr,
TTL: nil,
})
}
}
// Include additional answer types when a response is available
if resp != nil {
// Include CNAME if available
if cname, err := resp.DecodeCNAME(); err == nil && cname != "" {
out = append(out, model.ArchivalDNSAnswer{
ASN: 0,
ASOrgName: "",
AnswerType: "CNAME",
Hostname: cname,
IPv4: "",
IPv6: "",
TTL: nil,
})
}
// TODO(bassosimone): what other fields generally present inside A/AAAA replies
// would it be useful to extract here? Perhaps, the SoA field?
}
return
}