commit 7a3efe25d9625a566d08eae7ab9ffd862c1d4a6d Author: Alexander Færøy ahf@torproject.org Date: Fri May 12 13:55:18 2017 +0200

Use different preferences for compression methods when streaming.

See: https://bugs.torproject.org/21667 --- src/or/directory.c | 36 ++++++++++++++++++++++++++++-------- 1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/src/or/directory.c b/src/or/directory.c index d9d402a..4a528f2 100644 --- a/src/or/directory.c +++ b/src/or/directory.c @@ -3296,6 +3296,15 @@ static compress_method_t srv_meth_pref_precompressed[] = { NO_METHOD };

+/** Array of compression methods to use (if supported) for serving + * streamed data, ordered from best to worst. */ +static compress_method_t srv_meth_pref_streaming_compression[] = { + ZSTD_METHOD, + ZLIB_METHOD, + GZIP_METHOD, + NO_METHOD +}; + /** Parse the compression methods listed in an Accept-Encoding header <b>h</b>, * and convert them to a bitfield where compression method x is supported if * and only if 1 &lt;&lt; x is set in the bitfield. */ @@ -3700,11 +3709,22 @@ find_best_diff(const smartlist_t *digests, int flav, * <b>compression_methods</b>. Return NO_METHOD if no mutually supported * compression method could be found. */ static compress_method_t -find_best_compression_method(unsigned compression_methods) +find_best_compression_method(unsigned compression_methods, int stream) { unsigned u; - for (u = 0; u < ARRAY_LENGTH(srv_meth_pref_precompressed); ++u) { - compress_method_t method = srv_meth_pref_precompressed[u]; + compress_method_t *methods; + size_t length; + + if (stream) { + methods = srv_meth_pref_streaming_compression; + length = ARRAY_LENGTH(srv_meth_pref_streaming_compression); + } else { + methods = srv_meth_pref_precompressed; + length = ARRAY_LENGTH(srv_meth_pref_precompressed); + } + + for (u = 0; u < length; ++u) { + compress_method_t method = methods[u]; if (compression_methods & (1u<<method)) return method; } @@ -3720,7 +3740,7 @@ handle_get_current_consensus(dir_connection_t *conn, { const char *url = args->url; const compress_method_t compress_method = - find_best_compression_method(args->compression_supported); + find_best_compression_method(args->compression_supported, 0); const time_t if_modified_since = args->if_modified_since; int clear_spool = 0;

@@ -3878,7 +3898,7 @@ handle_get_status_vote(dir_connection_t *conn, const get_handler_args_t *args) { const char *url = args->url; const compress_method_t compress_method = - find_best_compression_method(args->compression_supported); + find_best_compression_method(args->compression_supported, 1); { int current; ssize_t body_len = 0; @@ -3990,7 +4010,7 @@ handle_get_microdesc(dir_connection_t *conn, const get_handler_args_t *args) { const char *url = args->url; const compress_method_t compress_method = - find_best_compression_method(args->compression_supported); + find_best_compression_method(args->compression_supported, 1); int clear_spool = 1; { conn->spool = smartlist_new(); @@ -4044,7 +4064,7 @@ handle_get_descriptor(dir_connection_t *conn, const get_handler_args_t *args) { const char *url = args->url; const compress_method_t compress_method = - find_best_compression_method(args->compression_supported); + find_best_compression_method(args->compression_supported, 1); const or_options_t *options = get_options(); int clear_spool = 1; if (!strcmpstart(url,"/tor/server/") || @@ -4138,7 +4158,7 @@ handle_get_keys(dir_connection_t *conn, const get_handler_args_t *args) { const char *url = args->url; const compress_method_t compress_method = - find_best_compression_method(args->compression_supported); + find_best_compression_method(args->compression_supported, 1); const time_t if_modified_since = args->if_modified_since; { smartlist_t *certs = smartlist_new();