From 36f808c9364bb2e6781e555697eac977d754e905 Mon Sep 17 00:00:00 2001
From: Nick Mathewson <nickm@torproject.org>
Date: Sun, 25 Nov 2018 10:05:13 -0500
Subject: [PATCH] Vote on the StaleDesc flag from prop293

The StaleDesc flag tells relays that they need to upload a new
descriptor soon, or they will drop out of the consensus.
---
 src/feature/dirauth/dirvote.c           | 3 ++-
 src/feature/dirauth/voteflags.c         | 4 ++++
 src/feature/dirauth/voteflags.h         | 3 +++
 src/feature/dirparse/ns_parse.c         | 2 ++
 src/feature/nodelist/fmt_routerstatus.c | 3 ++-
 src/feature/nodelist/routerstatus_st.h  | 2 ++
 6 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/feature/dirauth/dirvote.c b/src/feature/dirauth/dirvote.c
index 066a9e6e8a..aa4242f678 100644
--- a/src/feature/dirauth/dirvote.c
+++ b/src/feature/dirauth/dirvote.c
@@ -4620,7 +4620,8 @@ dirserv_generate_networkstatus_vote_obj(crypto_pk_t *private_key,
 
   v3_out->known_flags = smartlist_new();
   smartlist_split_string(v3_out->known_flags,
-                         "Authority Exit Fast Guard Stable V2Dir Valid HSDir",
+                         "Authority Exit Fast Guard Stable V2Dir Valid HSDir "
+                         "StaleDesc",
                          0, SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
   if (vote_on_reachability)
     smartlist_add_strdup(v3_out->known_flags, "Running");
diff --git a/src/feature/dirauth/voteflags.c b/src/feature/dirauth/voteflags.c
index 4a24dcb50d..5adf21ad11 100644
--- a/src/feature/dirauth/voteflags.c
+++ b/src/feature/dirauth/voteflags.c
@@ -593,6 +593,10 @@ set_routerstatus_from_routerinfo(routerstatus_t *rs,
   rs->or_port = ri->or_port;
   rs->dir_port = ri->dir_port;
   rs->is_v2_dir = ri->supports_tunnelled_dir_requests;
+
+  rs->is_staledesc =
+    (ri->cache_info.published_on + DESC_IS_STALE_INTERVAL) < now;
+
   if (options->AuthDirHasIPv6Connectivity == 1 &&
       !tor_addr_is_null(&ri->ipv6_addr) &&
       node->last_reachable6 >= now - REACHABLE_TIMEOUT) {
diff --git a/src/feature/dirauth/voteflags.h b/src/feature/dirauth/voteflags.h
index 2f0e061ea4..743a666cc8 100644
--- a/src/feature/dirauth/voteflags.h
+++ b/src/feature/dirauth/voteflags.h
@@ -25,6 +25,9 @@ void set_routerstatus_from_routerinfo(routerstatus_t *rs,
 void dirserv_compute_performance_thresholds(digestmap_t *omit_as_sybil);
 
 #ifdef VOTEFLAGS_PRIVATE
+/** Any descriptor older than this age causes the authorities to set the
+ * StaleDesc flag. */
+#define DESC_IS_STALE_INTERVAL (18*60*60)
 STATIC void dirserv_set_routerstatus_testing(routerstatus_t *rs);
 #endif
 
diff --git a/src/feature/dirparse/ns_parse.c b/src/feature/dirparse/ns_parse.c
index 3fccec1540..e0cdb2d46d 100644
--- a/src/feature/dirparse/ns_parse.c
+++ b/src/feature/dirparse/ns_parse.c
@@ -434,6 +434,8 @@ routerstatus_parse_entry_from_string(memarea_t *area,
         rs->is_hs_dir = 1;
       } else if (!strcmp(tok->args[i], "V2Dir")) {
         rs->is_v2_dir = 1;
+      } else if (!strcmp(tok->args[i], "StaleDesc")) {
+        rs->is_staledesc = 1;
       }
     }
     /* These are implied true by having been included in a consensus made
diff --git a/src/feature/nodelist/fmt_routerstatus.c b/src/feature/nodelist/fmt_routerstatus.c
index e70aeb2950..b1d4a48038 100644
--- a/src/feature/nodelist/fmt_routerstatus.c
+++ b/src/feature/nodelist/fmt_routerstatus.c
@@ -135,7 +135,7 @@ routerstatus_format_entry(const routerstatus_t *rs, const char *version,
     goto done;
 
   smartlist_add_asprintf(chunks,
-                   "s%s%s%s%s%s%s%s%s%s%s\n",
+                   "s%s%s%s%s%s%s%s%s%s%s%s\n",
                   /* These must stay in alphabetical order. */
                    rs->is_authority?" Authority":"",
                    rs->is_bad_exit?" BadExit":"",
@@ -145,6 +145,7 @@ routerstatus_format_entry(const routerstatus_t *rs, const char *version,
                    rs->is_hs_dir?" HSDir":"",
                    rs->is_flagged_running?" Running":"",
                    rs->is_stable?" Stable":"",
+                   rs->is_staledesc?" StaleDesc":"",
                    rs->is_v2_dir?" V2Dir":"",
                    rs->is_valid?" Valid":"");
 
diff --git a/src/feature/nodelist/routerstatus_st.h b/src/feature/nodelist/routerstatus_st.h
index 714aa27435..ea06587799 100644
--- a/src/feature/nodelist/routerstatus_st.h
+++ b/src/feature/nodelist/routerstatus_st.h
@@ -47,6 +47,8 @@ struct routerstatus_t {
   unsigned int is_v2_dir:1; /** True iff this router publishes an open DirPort
                              * or it claims to accept tunnelled dir requests.
                              */
+  unsigned int is_staledesc:1; /** True iff the authorities think this router
+                                * should upload a new descriptor soon. */
 
   unsigned int has_bandwidth:1; /**< The vote/consensus had bw info */
   unsigned int has_exitsummary:1; /**< The vote/consensus had exit summaries */