commit 452cfaacfc6e6b4313d2170c29e18d6399038999
Author: Nick Mathewson <nickm(a)torproject.org>
Date: Mon Mar 11 22:06:07 2013 -0400
Track TLS overhead: diagnostic for bug 7707
---
changes/bug7707_diagnostic | 5 +++++
src/common/tortls.c | 25 +++++++++++++++++++++++++
src/common/tortls.h | 2 ++
src/or/status.c | 6 ++++++
4 files changed, 38 insertions(+), 0 deletions(-)
diff --git a/changes/bug7707_diagnostic b/changes/bug7707_diagnostic
new file mode 100644
index 0000000..0c3138e
--- /dev/null
+++ b/changes/bug7707_diagnostic
@@ -0,0 +1,5 @@
+ o Minor features:
+ - Add another diagnostic to the heartbeat message: track and log
+ overhead that TLS is adding to the data we write. If this is
+ high, we are sending too little data to SSL_write at a time.
+ Diagnostic for bug 7707.
diff --git a/src/common/tortls.c b/src/common/tortls.c
index a08910b..b7e5bc1 100644
--- a/src/common/tortls.c
+++ b/src/common/tortls.c
@@ -1997,6 +1997,10 @@ tor_tls_free(tor_tls_t *tls)
if (!tls)
return;
tor_assert(tls->ssl);
+ {
+ size_t r,w;
+ tor_tls_get_n_raw_bytes(tls,&r,&w); /* ensure written_by_tls is updated */
+ }
#ifdef SSL_set_tlsext_host_name
SSL_set_tlsext_host_name(tls->ssl, NULL);
#endif
@@ -2048,6 +2052,13 @@ tor_tls_read(tor_tls_t *tls, char *cp, size_t len)
}
}
+/** Total number of bytes that we've used TLS to send. Used to track TLS
+ * overhead. */
+static uint64_t total_bytes_written_over_tls = 0;
+/** Total number of bytes that TLS has put on the network for us. Used to
+ * track TLS overhead. */
+static uint64_t total_bytes_written_by_tls = 0;
+
/** Underlying function for TLS writing. Write up to <b>n</b>
* characters from <b>cp</b> onto <b>tls</b>. On success, returns the
* number of characters written. On failure, returns TOR_TLS_ERROR,
@@ -2074,6 +2085,7 @@ tor_tls_write(tor_tls_t *tls, const char *cp, size_t n)
r = SSL_write(tls->ssl, cp, (int)n);
err = tor_tls_get_error(tls, r, 0, "writing", LOG_INFO, LD_NET);
if (err == TOR_TLS_DONE) {
+ total_bytes_written_over_tls += r;
return r;
}
if (err == TOR_TLS_WANTWRITE || err == TOR_TLS_WANTREAD) {
@@ -2563,10 +2575,23 @@ tor_tls_get_n_raw_bytes(tor_tls_t *tls, size_t *n_read, size_t *n_written)
"r=%lu, last_read=%lu, w=%lu, last_written=%lu",
r, tls->last_read_count, w, tls->last_write_count);
}
+ total_bytes_written_by_tls += *n_written;
tls->last_read_count = r;
tls->last_write_count = w;
}
+/** Return a ratio of the bytes that TLS has sent to the bytes that we've told
+ * it to send. Used to track whether our TLS records are getting too tiny. */
+double
+tls_get_write_overhead_ratio(void)
+{
+ if (total_bytes_written_over_tls == 0)
+ return 1.0;
+
+ return U64_TO_DBL(total_bytes_written_by_tls) /
+ U64_TO_DBL(total_bytes_written_over_tls);
+}
+
/** Implement check_no_tls_errors: If there are any pending OpenSSL
* errors, log an error message. */
void
diff --git a/src/common/tortls.h b/src/common/tortls.h
index 1ae6344..49c488b 100644
--- a/src/common/tortls.h
+++ b/src/common/tortls.h
@@ -95,6 +95,8 @@ void tor_tls_get_buffer_sizes(tor_tls_t *tls,
size_t *rbuf_capacity, size_t *rbuf_bytes,
size_t *wbuf_capacity, size_t *wbuf_bytes);
+double tls_get_write_overhead_ratio(void);
+
int tor_tls_used_v1_handshake(tor_tls_t *tls);
int tor_tls_received_v3_certificate(tor_tls_t *tls);
int tor_tls_get_num_server_handshakes(tor_tls_t *tls);
diff --git a/src/or/status.c b/src/or/status.c
index 126167d..e44de63 100644
--- a/src/or/status.c
+++ b/src/or/status.c
@@ -85,6 +85,7 @@ log_heartbeat(time_t now)
char *bw_rcvd = NULL;
char *uptime = NULL;
const routerinfo_t *me;
+ double r = tls_get_write_overhead_ratio();
const or_options_t *options = get_options();
(void)now;
@@ -112,6 +113,11 @@ log_heartbeat(time_t now)
100*(U64_TO_DBL(stats_n_data_bytes_packaged) /
U64_TO_DBL(stats_n_data_cells_packaged*RELAY_PAYLOAD_SIZE)) );
+ if (r > 1.0) {
+ double overhead = ( r - 1.0 ) * 100.0;
+ log_notice(LD_HEARTBEAT, "TLS write overhead: %.f%%", overhead);
+ }
+
tor_free(uptime);
tor_free(bw_sent);
tor_free(bw_rcvd);