commit da6b00443c266f1f0928ae02c3832123cbaa9455 Author: Nick Mathewson nickm@torproject.org Date: Thu May 4 11:25:33 2017 -0400

Try not to mess up caches with the X-Or-Diff-From-Consensus header --- src/or/directory.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/or/directory.c b/src/or/directory.c index 4537d79..aca3030 100644 --- a/src/or/directory.c +++ b/src/or/directory.c @@ -3288,8 +3288,9 @@ write_http_response_header_impl(dir_connection_t *conn, ssize_t length, /** As write_http_response_header_impl, but sets encoding and content-typed * based on whether the response will be <b>compressed</b> or not. */ static void -write_http_response_header(dir_connection_t *conn, ssize_t length, - compress_method_t method, long cache_lifetime) +write_http_response_headers(dir_connection_t *conn, ssize_t length, + compress_method_t method, + const char *extra_headers, long cache_lifetime) { const char *methodname = compression_method_get_name(method); const char *doctype; @@ -3300,10 +3301,19 @@ write_http_response_header(dir_connection_t *conn, ssize_t length, write_http_response_header_impl(conn, length, doctype, methodname, - NULL, + extra_headers, cache_lifetime); }

+/** As write_http_response_headers, but assumes extra_headers is NULL */ +static void +write_http_response_header(dir_connection_t *conn, ssize_t length, + compress_method_t method, + long cache_lifetime) +{ + write_http_response_headers(conn, length, method, NULL, cache_lifetime); +} + /** Array of compression methods to use (if supported) for serving * precompressed data, ordered from best to worst. */ static compress_method_t srv_meth_pref_precompressed[] = { @@ -4056,14 +4066,19 @@ handle_get_current_consensus(dir_connection_t *conn, DIRREQ_DIRECT); }

+ /* Use this header to tell caches that the response depends on the + * X-Or-Diff-From-Consensus header (or lack thereof). */ + const char vary_header[] = "Vary: X-Or-Diff-From-Consensus\r\n"; + clear_spool = 0;

// The compress_method might have been NO_METHOD, but we store the data // compressed. Decompress them using `compression_used`. See fallback code in // find_best_consensus() and find_best_diff(). - write_http_response_header(conn, -1, + write_http_response_headers(conn, -1, compress_method == NO_METHOD ? NO_METHOD : compression_used, + vary_header, smartlist_len(conn->spool) == 1 ? lifetime : 0);

if (compress_method == NO_METHOD)