bwauth: Ignore bandwidth file lines with "vote=0"

so that the relays that would be "excluded" from the bandwidth
file because of something failed can be included to diagnose what
failed, without still including these relays in the bandwidth
authorities vote.

Closes #29806.

changes/ticket29806

@@ -0,0 +1,7 @@
+  o Minor features (bandwidth authority):
+    - Make bandwidth authorities to ignore relays that are reported in the
+      bandwidth file with the key-value "vote=0".
+      This change allows to report the relays that were not measured due
+      some failure and diagnose the reasons without the bandwidth being included in the
+      bandwidth authorities vote.
+      Closes ticket 29806.

src/or/dirserv.c

@@ -2497,7 +2497,13 @@ measured_bw_line_parse(measured_bw_line_t *out, const char *orig_line,
   }
 
   do {
-    if (strcmpstart(cp, "bw=") == 0) {
+    // If the line contains vote=0, ignore it.
+    if (strcmpstart(cp, "vote=0") == 0) {
+      log_debug(LD_DIRSERV, "Ignoring bandwidth file line that contains "
+                "vote=0: %s",escaped(orig_line));
+      tor_free(line);
+      return -1;
+    } else if (strcmpstart(cp, "bw=") == 0) {
       int parse_ok = 0;
       char *endptr;
       if (got_bw) {

src/test/test_dir.c

@@ -1508,6 +1508,19 @@ test_dir_measured_bw_kb(void *arg)
     /* check whether node_id can be at the end and something in the
      * in the middle of bw and node_id */
     "bw=1024 foo=bar node_id=$557365204145532d32353620696e73746561642e\n",
+
+    /* Test that a line with vote=1 will pass. */
+    "node_id=$557365204145532d32353620696e73746561642e bw=1024 vote=1\n",
+    /* Test that a line with unmeasured=1 will pass. */
+    "node_id=$557365204145532d32353620696e73746561642e bw=1024 unmeasured=1\n",
+    /* Test that a line with vote=1 and unmeasured=1 will pass. */
+    "node_id=$557365204145532d32353620696e73746561642e bw=1024 vote=1"
+    "unmeasured=1\n",
+    /* Test that a line with unmeasured=0 will pass. */
+    "node_id=$557365204145532d32353620696e73746561642e bw=1024 unmeasured=0\n",
+    /* Test that a line with vote=1 and unmeasured=0 will pass. */
+    "node_id=$557365204145532d32353620696e73746561642e bw=1024 vote=1"
+    "unmeasured=0\n",
     "end"
   };
   const char *lines_fail[] = {
@@ -1541,6 +1554,12 @@ test_dir_measured_bw_kb(void *arg)
     "node_id=$55736520414552d32353620696e73746561642e bw=1024\n",
     "node_id=557365204145532d32353620696e73746561642e bw=1024\n",
     "node_id= $557365204145532d32353620696e73746561642e bw=0.23\n",
+
+    /* Test that a line with vote=0 will fail too, so that it is ignored. */
+    "node_id=$557365204145532d32353620696e73746561642e bw=1024 vote=0\n",
+    /* Test that a line with vote=0 will fail even if unmeasured=0. */
+    "node_id=$557365204145532d32353620696e73746561642e bw=1024 vote=0 "
+    "unmeasured=0\n",
     "end"
   };
 
@@ -1706,6 +1725,44 @@ test_dir_dirserv_read_measured_bandwidths(void *arg)
   tor_free(content);
   tt_int_op(0, OP_EQ, dirserv_read_measured_bandwidths(fname, NULL));
 
+  /* Test v1.x.x bandwidth line with vote=0.
+   * It will be ignored it and logged it at debug level. */
+  const char *relay_lines_ignore =
+    "node_id=$68A483E05A2ABDCA6DA5A3EF8DB5177638A27F80 bw=1024 vote=0\n"
+    "node_id=$68A483E05A2ABDCA6DA5A3EF8DB5177638A27F80 bw=1024 vote=0"
+    "unmeasured=1\n"
+    "node_id=$68A483E05A2ABDCA6DA5A3EF8DB5177638A27F80 bw=1024 vote=0"
+    "unmeasured=0\n";
+
+  /* Create the bandwidth file */
+  tor_asprintf(&content, "%ld\n%s", (long)timestamp, relay_lines_ignore);
+  write_str_to_file(fname, content, 0);
+  tor_free(content);
+
+  /* Read the bandwidth file */
+  setup_full_capture_of_logs(LOG_DEBUG);
+  tt_int_op(0, OP_EQ, dirserv_read_measured_bandwidths(fname, NULL));
+  expect_log_msg_containing("Ignoring bandwidth file line");
+  teardown_capture_of_logs();
+
+  /* Test v1.x.x bandwidth line with "vote=1" or "unmeasured=1" or
+   * "unmeasured=0".
+   * They will not be ignored. */
+  /* Create the bandwidth file */
+  const char *relay_lines_vote =
+    "node_id=$68A483E05A2ABDCA6DA5A3EF8DB5177638A27F80 bw=1024 vote=1\n"
+    "node_id=$68A483E05A2ABDCA6DA5A3EF8DB5177638A27F80 bw=1024 unmeasured=0\n"
+    "node_id=$68A483E05A2ABDCA6DA5A3EF8DB5177638A27F80 bw=1024 unmeasured=1\n";
+  tor_asprintf(&content, "%ld\n%s", (long)timestamp, relay_lines_vote);
+  write_str_to_file(fname, content, 0);
+  tor_free(content);
+
+  /* Read the bandwidth file */
+  setup_full_capture_of_logs(LOG_DEBUG);
+  tt_int_op(0, OP_EQ, dirserv_read_measured_bandwidths(fname, NULL));
+  expect_log_msg_not_containing("Ignoring bandwidth file line");
+  teardown_capture_of_logs();
+
  done:
   tor_free(fname);
 }