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Perf: Replace casecmp with memcmp in HPACK static table lookup #6521

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Merged
masaori335 merged 1 commit into from
Feb 5, 2021
+16 −20
Merged

Perf: Replace casecmp with memcmp in HPACK static table lookup #6521

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36 changes: 16 additions & 20 deletions proxy/http2/HPACK.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -231,9 +231,8 @@ namespace HpackStaticTable
std::string_view name = STATIC_TABLE[index].name;
std::string_view value = STATIC_TABLE[index].value;

// TODO: replace `strcasecmp` with `memcmp`
// Check whether name (and value) are matched
if (strcasecmp(header.name, name) == 0) {
if (memcmp(header.name, name) == 0) {
if (memcmp(header.value, value) == 0) {
result.index = index;
result.index_type = HpackIndex::STATIC;
Expand Down Expand Up @@ -619,19 +618,8 @@ encode_literal_header_field_with_new_name(uint8_t *buf_start, const uint8_t *buf
}
*(p++) = flag;

// Convert field name to lower case to follow HTTP2 spec.
// This conversion is needed because WKSs in MIMEFields is old fashioned
int name_len = header.name.size();
const char *original_name = header.name.data();

ts::LocalBuffer<char> local_buffer(name_len);
char *lower_name = local_buffer.data();
for (int i = 0; i < name_len; i++) {
lower_name[i] = ParseRules::ink_tolower(original_name[i]);
}

// Name String
len = xpack_encode_string(p, buf_end, lower_name, name_len);
len = xpack_encode_string(p, buf_end, header.name.data(), header.name.size());
if (len == -1) {
return -1;
}
Expand All @@ -645,8 +633,8 @@ encode_literal_header_field_with_new_name(uint8_t *buf_start, const uint8_t *buf

p += len;

Debug("hpack_encode", "Encoded field: %.*s: %.*s", name_len, lower_name, static_cast<int>(header.value.size()),
header.value.data());
Debug("hpack_encode", "Encoded field: %.*s: %.*s", static_cast<int>(header.name.size()), header.name.data(),
static_cast<int>(header.value.size()), header.value.data());

return p - buf_start;
}
Expand Down Expand Up @@ -922,16 +910,24 @@ hpack_encode_header_block(HpackIndexingTable &indexing_table, uint8_t *out_buf,

MIMEFieldIter field_iter;
for (MIMEField *field = hdr->iter_get_first(&field_iter); field != nullptr; field = hdr->iter_get_next(&field_iter)) {
std::string_view name = field->name_get();
// Convert field name to lower case to follow HTTP2 spec
// This conversion is needed because WKSs in MIMEFields is old fashioned
std::string_view original_name = field->name_get();
int name_len = original_name.size();
ts::LocalBuffer<char> local_buffer(name_len);
char *lower_name = local_buffer.data();
for (int i = 0; i < name_len; i++) {
lower_name[i] = ParseRules::ink_tolower(original_name[i]);
}

std::string_view name{lower_name, static_cast<size_t>(name_len)};
std::string_view value = field->value_get();

// Choose field representation (See RFC7541 7.1.3)
// - Authorization header obviously should not be indexed
// - Short Cookie header should not be indexed because of low entropy
HpackField field_type;
// TODO: replace `strcasecmp` with `memcmp`
if ((value.size() < 20 && strcasecmp(name, HPACK_HDR_FIELD_COOKIE) == 0) ||
(strcasecmp(name, HPACK_HDR_FIELD_AUTHORIZATION) == 0)) {
if ((value.size() < 20 && memcmp(name, HPACK_HDR_FIELD_COOKIE) == 0) || memcmp(name, HPACK_HDR_FIELD_AUTHORIZATION) == 0) {
field_type = HpackField::NEVERINDEX_LITERAL;
} else {
field_type = HpackField::INDEXED_LITERAL;
Expand Down