rend-spec-v3.txt: Merge prop305 in it

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

1 files changed, 62 insertions, 0 deletions

diff --git a/rend-spec-v3.txt b/rend-spec-v3.txt
index a3e0b0a..68f6c28 100644
--- a/rend-spec-v3.txt
+++ b/rend-spec-v3.txt
@@ -50,6 +50,7 @@ Table of contents:
     3. The introduction protocol [INTRO-PROTOCOL]
         3.1. Registering an introduction point [REG_INTRO_POINT]
             3.1.1. Extensible ESTABLISH_INTRO protocol. [EST_INTRO]
+               3.1.1.1. Denial-of-Server Defense Extension. [EST_INTRO_DOS_EXT]
             3.1.2. Registering an introduction point on a legacy Tor node [LEGACY_EST_INTRO]
             3.1.3. Acknowledging establishment of introduction point [INTRO_ESTABLISHED]
         3.2. Sending an INTRODUCE1 cell to the introduction point. [SEND_INTRO1]
@@ -1566,6 +1567,67 @@ Table of contents:
    Otherwise, the node must associate the key with the circuit, for use
    later in INTRODUCE1 cells.
 
+3.1.1.1. Denial-of-Service Defense Extension. [EST_INTRO_DOS_EXT]
+
+   This extension can be used to send Denial-of-Service (DoS) parameters to
+   the introduction point in order for it to apply them for the introduction
+   circuit.
+
+   If used, it needs to be encoded within the N_EXTENSIONS field of the
+   ESTABLISH_INTRO cell defined in the previous section. The content is
+   defined as follow:
+
+      EXT_FIELD_TYPE:
+
+         [01] -- Denial-of-Service Parameters.
+
+         If this flag is set, the extension should be used by the introduction
+         point to learn what values the denial of service subsystem should be
+         using.
+
+      EXT_FIELD content format is:
+
+        N_PARAMS       [1 byte]
+        N_PARAMS times:
+           PARAM_TYPE  [1 byte]
+           PARAM_VALUE [8 byte]
+
+        The PARAM_TYPE possible values are:
+
+         [01] -- DOS_INTRODUCE2_RATE_PER_SEC
+                 The rate per second of INTRODUCE2 cell relayed to the
+                 service.
+
+         [02] -- DOS_INTRODUCE2_BURST_PER_SEC
+                 The burst per second of INTRODUCE2 cell relayed to the
+                 service.
+
+        The PARAM_VALUE size is 8 bytes in order to accomodate 64bit values.
+        It MUST match the specified limit for the following PARAM_TYPE:
+
+         [01] -- Min: 0, Max: 2147483647
+         [02] -- Min: 0, Max: 2147483647
+
+        A value of 0 means the defense is disabled. If the rate per second is
+        set to 0 (param 0x01) then the burst value should be ignored. And
+        vice-versa, if the burst value is 0 (param 0x02), then the rate value
+        should be ignored. In other words, setting one single parameter to 0
+        disables the defense.
+
+        The burst can NOT be smaller than the rate. If so, the parameters
+        should be ignored by the introduction point.
+
+        Any valid value does have precedence over the network wide consensus
+        parameter.
+
+   Using this extension extends the payload of the ESTABLISH_INTRO cell by 19
+   bytes bringing it from 134 bytes to 155 bytes.
+
+   This extension can only be used with relays supporting the protocol version
+   "HSIntro=5".
+
+   Introduced in tor-0.4.2.1-alpha.
+
 3.1.2. Registering an introduction point on a legacy Tor node
        [LEGACY_EST_INTRO]