hs: Decode flow-control line

This puts the flow control version (unparsed) in the descriptor. The
client doesn't use it yet.

Signed-off-by: David Goulet <dgoulet@torproject.org>

src/feature/hs/hs_descriptor.c

@@ -2347,6 +2347,23 @@ desc_decode_encrypted_v3(const hs_descriptor_t *desc,
     desc_encrypted_out->single_onion_service = 1;
   }
 
+  /* Get flow control if any. */
+  tok = find_opt_by_keyword(tokens, R3_FLOW_CONTROL);
+  if (tok) {
+    int ok;
+
+    tor_asprintf(&desc_encrypted_out->flow_control_pv, "FlowCtrl=%s",
+                 tok->args[0]);
+    uint8_t sendme_inc =
+      (uint8_t) tor_parse_uint64(tok->args[1], 10, 0, UINT8_MAX, &ok, NULL);
+    if (!ok || !congestion_control_validate_sendme_increment(sendme_inc)) {
+      log_warn(LD_REND, "Service descriptor flow control sendme "
+                        "value is invalid");
+      goto err;
+    }
+    desc_encrypted_out->sendme_inc = sendme_inc;
+  }
+
   /* Initialize the descriptor's introduction point list before we start
    * decoding. Having 0 intro point is valid. Then decode them all. */
   desc_encrypted_out->intro_points = smartlist_new();
@@ -2757,6 +2774,7 @@ hs_desc_encrypted_data_free_contents(hs_desc_encrypted_data_t *desc)
                       hs_desc_intro_point_free(ip));
     smartlist_free(desc->intro_points);
   }
+  tor_free(desc->flow_control_pv);
   memwipe(desc, 0, sizeof(*desc));
 }
 

src/feature/hs/hs_descriptor.h

@@ -167,6 +167,10 @@ typedef struct hs_desc_encrypted_data_t {
   /** Is this descriptor a single onion service? */
   unsigned int single_onion_service : 1;
 
+  /** Flow control protocol version line. */
+  char *flow_control_pv;
+  uint8_t sendme_inc;
+
   /** A list of intro points. Contains hs_desc_intro_point_t objects. */
   smartlist_t *intro_points;
 } hs_desc_encrypted_data_t;

src/test/hs_test_helpers.c

@@ -4,6 +4,7 @@
 #define HS_CLIENT_PRIVATE
 
 #include "core/or/or.h"
+#include "core/or/versions.h"
 #include "lib/crypt_ops/crypto_ed25519.h"
 #include "test/test.h"
 #include "feature/nodelist/torcert.h"
@@ -186,6 +187,7 @@ hs_helper_build_hs_desc_impl(unsigned int no_ip,
   desc->encrypted_data.create2_ntor = 1;
   desc->encrypted_data.intro_auth_types = smartlist_new();
   desc->encrypted_data.single_onion_service = 1;
+  desc->encrypted_data.flow_control_pv = tor_strdup("FlowCtrl=1-2");
   smartlist_add(desc->encrypted_data.intro_auth_types, tor_strdup("ed25519"));
   desc->encrypted_data.intro_points = smartlist_new();
   if (!no_ip) {
@@ -332,6 +334,10 @@ hs_helper_desc_equal(const hs_descriptor_t *desc1,
   /* Encrypted data section. */
   tt_uint_op(desc1->encrypted_data.create2_ntor, OP_EQ,
              desc2->encrypted_data.create2_ntor);
+  tt_uint_op(desc1->encrypted_data.single_onion_service, OP_EQ,
+             desc2->encrypted_data.single_onion_service);
+  tt_str_op(desc1->encrypted_data.flow_control_pv, OP_EQ,
+            desc2->encrypted_data.flow_control_pv);
 
   /* Authentication type. */
   tt_int_op(!!desc1->encrypted_data.intro_auth_types, OP_EQ,

src/test/test_protover.c

@@ -355,6 +355,9 @@ test_protover_supports_version(void *arg)
 #define PROTOVER_PADDING_V1 1
 
 #define PROTOVER_FLOWCTRL_V1 1
+#define PROTOVER_FLOWCTRL_V2 2
+
+#define PROTOVER_RELAY_NTOR_V3 4
 
 /* Make sure we haven't forgotten any supported protocols */
 static void
@@ -644,7 +647,8 @@ test_protover_vote_roundtrip_ours(void *args)
             "supports_establish_intro_dos_extension: %d,\n" \
             "supports_v3_hsdir: %d,\n" \
             "supports_v3_rendezvous_point: %d,\n" \
-            "supports_hs_setup_padding: %d.", \
+            "supports_hs_setup_padding: %d,\n" \
+            "supports_congestion_control: %d.", \
             (flags).protocols_known, \
             (flags).supports_extend2_cells, \
             (flags).supports_accepting_ipv6_extends, \
@@ -656,7 +660,8 @@ test_protover_vote_roundtrip_ours(void *args)
             (flags).supports_establish_intro_dos_extension, \
             (flags).supports_v3_hsdir, \
             (flags).supports_v3_rendezvous_point, \
-            (flags).supports_hs_setup_padding); \
+            (flags).supports_hs_setup_padding, \
+            (flags).supports_congestion_control); \
     STMT_END
 
 /* Test that the proto_string version version_macro sets summary_flag. */
@@ -699,6 +704,22 @@ test_protover_summarize_flags(void *args)
 
   /* Now check version exceptions */
 
+  /* Congestion control. */
+  memset(&flags, 0, sizeof(flags));
+  summarize_protover_flags(&flags,
+                           PROTOVER("FlowCtrl", PROTOVER_FLOWCTRL_V2),
+                           NULL);
+  summarize_protover_flags(&flags,
+                           PROTOVER("Relay", PROTOVER_RELAY_NTOR_V3),
+                           NULL);
+  DEBUG_PROTOVER(flags);
+  tt_int_op(flags.protocols_known, OP_EQ, 1);
+  tt_int_op(flags.supports_congestion_control, OP_EQ, 1);
+  /* Now clear those flags, and check the rest are zero */
+  flags.protocols_known = 0;
+  flags.supports_congestion_control = 0;
+  tt_mem_op(&flags, OP_EQ, &zero_flags, sizeof(flags));
+
   /* EXTEND2 cell support */
   memset(&flags, 0, sizeof(flags));
   summarize_protover_flags(&flags, NULL, "Tor 0.2.4.8-alpha");