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feat: speed up incoming data parser #1161

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Merged
bdraco merged 1 commit into from
Apr 23, 2023
Merged

feat: speed up incoming data parser #1161

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2 changes: 1 addition & 1 deletion src/zeroconf/_dns.pxd
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Original file line number Diff line number Diff line change
Expand Up @@ -105,4 +105,4 @@ cdef class DNSRRSet:
cpdef suppresses(self, DNSRecord record)

@cython.locals(lookup=cython.dict)
cdef _get_lookup(self)
cdef cython.dict _get_lookup(self)
4 changes: 3 additions & 1 deletion src/zeroconf/_dns.py
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Expand Up @@ -538,4 +538,6 @@ def suppresses(self, record: _DNSRecord) -> bool:
information held in this record."""
lookup = self._get_lookup()
other_ttl = lookup.get(record)
return bool(other_ttl and other_ttl > (record.ttl / 2))
if other_ttl is None:
return False
return other_ttl > (record.ttl / 2)
9 changes: 5 additions & 4 deletions src/zeroconf/_protocol/incoming.pxd
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Expand Up @@ -35,10 +35,10 @@ cdef class DNSIncoming:

cdef bint _did_read_others
cdef public unsigned int flags
cdef unsigned int offset
cdef object offset
cdef public bytes data
cdef unsigned int _data_len
cdef public object name_cache
cdef public cython.dict name_cache
cdef public object questions
cdef object _answers
cdef public object id
Expand All @@ -55,9 +55,10 @@ cdef class DNSIncoming:
off=cython.uint,
label_idx=cython.uint,
length=cython.uint,
link=cython.uint
link=cython.uint,
link_data=cython.uint
)
cdef _decode_labels_at_offset(self, unsigned int off, cython.list labels, object seen_pointers)
cdef _decode_labels_at_offset(self, unsigned int off, cython.list labels, cython.set seen_pointers)

cdef _read_header(self)

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13 changes: 8 additions & 5 deletions src/zeroconf/_protocol/incoming.py
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Expand Up @@ -353,7 +353,9 @@ def _decode_labels_at_offset(self, off: int, labels: List[str], seen_pointers: S
)

# We have a DNS compression pointer
link = (length & 0x3F) * 256 + self.data[off + 1]
link_data = self.data[off + 1]
link = (length & 0x3F) * 256 + link_data
lint_int = int(link)
if link > self._data_len:
raise IncomingDecodeError(
f"DNS compression pointer at {off} points to {link} beyond packet from {self.source}"
Expand All @@ -362,15 +364,16 @@ def _decode_labels_at_offset(self, off: int, labels: List[str], seen_pointers: S
raise IncomingDecodeError(
f"DNS compression pointer at {off} points to itself from {self.source}"
)
if link in seen_pointers:
if lint_int in seen_pointers:
raise IncomingDecodeError(
f"DNS compression pointer at {off} was seen again from {self.source}"
)
linked_labels = self.name_cache.get(link, [])
linked_labels = self.name_cache.get(lint_int)
if not linked_labels:
seen_pointers.add(link)
linked_labels = []
seen_pointers.add(lint_int)
self._decode_labels_at_offset(link, linked_labels, seen_pointers)
self.name_cache[link] = linked_labels
self.name_cache[lint_int] = linked_labels
labels.extend(linked_labels)
if len(labels) > MAX_DNS_LABELS:
raise IncomingDecodeError(
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