nghttpx: Send nghttpx-0rtt-uniq header if request is replayable

The incoming nghttpx-0rtt-uniq header fields from inbound client are
stripped by default.  Use --no-strip-incoming-nghttpx-0rtt-uniq in
order not to strip them.

genheaderfunc.py

@@ -31,6 +31,7 @@ HEADERS = [
     "user-agent",
     "date",
     "content-type",
+    "nghttpx-0rtt-uniq",
     # disallowed h1 headers
     'connection',
     'keep-alive',

gennghttpxfun.py

@@ -172,6 +172,7 @@ OPTIONS = [
     "tls-anti-replay-memcached-cert-file",
     "tls-anti-replay-memcached-private-key-file",
     "tls-anti-replay-memcached-address-family",
+    "no-strip-incoming-nghttpx-0rtt-uniq",
 ]
 
 LOGVARS = [

src/http2.cc

@@ -434,6 +434,11 @@ void copy_headers_to_nva_internal(std::vector<nghttp2_nv> &nva,
       kv = &(*it_via);
       it_via = it;
       break;
+    case HD_NGHTTPX_0RTT_UNIQ:
+      if (flags & HDOP_STRIP_NGHTTPX_ZERO_RTT_UNIQ) {
+        continue;
+      }
+      break;
     }
     nva.push_back(
         make_nv_internal(kv->name, kv->value, kv->no_index, nv_flags));
@@ -920,6 +925,11 @@ int lookup_token(const uint8_t *name, size_t namelen) {
         return HD_X_FORWARDED_PROTO;
       }
       break;
+    case 'q':
+      if (util::streq_l("nghttpx-0rtt-uni", name, 16)) {
+        return HD_NGHTTPX_0RTT_UNIQ;
+      }
+      break;
     }
     break;
   }

src/http2.h

@@ -203,9 +203,13 @@ enum HeaderBuildOp {
   // Via header fields must be stripped.  If this flag is not set, all
   // Via header fields other than last one are added.
   HDOP_STRIP_VIA = 1 << 3,
+  // nghttpx-0rtt-uniq header fields must be stripped.  If this flag
+  // is not set, all nghttpx-0rtt-uniq header fields are added.
+  HDOP_STRIP_NGHTTPX_ZERO_RTT_UNIQ = 1 << 4,
   // Strip above all header fields.
   HDOP_STRIP_ALL = HDOP_STRIP_FORWARDED | HDOP_STRIP_X_FORWARDED_FOR |
-                   HDOP_STRIP_X_FORWARDED_PROTO | HDOP_STRIP_VIA,
+                   HDOP_STRIP_X_FORWARDED_PROTO | HDOP_STRIP_VIA |
+                   HDOP_STRIP_NGHTTPX_ZERO_RTT_UNIQ,
 };
 
 // Appends headers in |headers| to |nv|.  |headers| must be indexed
@@ -312,6 +316,7 @@ enum {
   HD_KEEP_ALIVE,
   HD_LINK,
   HD_LOCATION,
+  HD_NGHTTPX_0RTT_UNIQ,
   HD_PROXY_CONNECTION,
   HD_SERVER,
   HD_TE,

src/shrpx.cc

@@ -1486,6 +1486,7 @@ void fill_default_config(Config *config) {
   httpconf.max_requests = std::numeric_limits<size_t>::max();
   httpconf.xfp.add = true;
   httpconf.xfp.strip_incoming = true;
+  httpconf.zero_rtt_uniq.strip_incoming = true;
 
   auto &http2conf = config->http2;
   {
@@ -2615,6 +2616,9 @@ HTTP:
               Default: obfuscated
   --no-via    Don't append to  Via header field.  If  Via header field
               is received, it is left unaltered.
+  --no-strip-incoming-nghttpx-0rtt-uniq
+              Don't strip nghttpx-0rtt-uniq  header field from inbound
+              client requests.
   --no-location-rewrite
               Don't  rewrite location  header field  in default  mode.
               When --http2-proxy  is used, location header  field will
@@ -3457,6 +3461,8 @@ int main(int argc, char **argv) {
          required_argument, &flag, 162},
         {SHRPX_OPT_TLS_ANTI_REPLAY_MEMCACHED_PRIVATE_KEY_FILE.c_str(),
          required_argument, &flag, 163},
+        {SHRPX_OPT_NO_STRIP_INCOMING_NGHTTPX_0RTT_UNIQ.c_str(), no_argument,
+         &flag, 164},
         {nullptr, 0, nullptr, 0}};
 
     int option_index = 0;
@@ -4239,6 +4245,11 @@ int main(int argc, char **argv) {
             SHRPX_OPT_TLS_ANTI_REPLAY_MEMCACHED_PRIVATE_KEY_FILE,
             StringRef{optarg});
         break;
+      case 164:
+        // --no-strip-incoming-nghttpx-0rtt-uniq
+        cmdcfgs.emplace_back(SHRPX_OPT_NO_STRIP_INCOMING_NGHTTPX_0RTT_UNIQ,
+                             StringRef::from_lit("yes"));
+        break;
       default:
         break;
       }

src/shrpx_config.cc

@@ -2269,6 +2269,11 @@ int option_lookup_token(const char *name, size_t namelen) {
         return SHRPX_OPTID_NO_STRIP_INCOMING_X_FORWARDED_PROTO;
       }
       break;
+    case 'q':
+      if (util::strieq_l("no-strip-incoming-nghttpx-0rtt-uni", name, 34)) {
+        return SHRPX_OPTID_NO_STRIP_INCOMING_NGHTTPX_0RTT_UNIQ;
+      }
+      break;
     case 'r':
       if (util::strieq_l("frontend-http2-dump-response-heade", name, 34)) {
         return SHRPX_OPTID_FRONTEND_HTTP2_DUMP_RESPONSE_HEADER;
@@ -3590,6 +3595,10 @@ int parse_config(Config *config, int optid, const StringRef &opt,
   case SHRPX_OPTID_NO_VERIFY_OCSP:
     config->tls.ocsp.no_verify = util::strieq_l("yes", optarg);
 
+    return 0;
+  case SHRPX_OPTID_NO_STRIP_INCOMING_NGHTTPX_0RTT_UNIQ:
+    config->http.zero_rtt_uniq.strip_incoming = !util::strieq_l("yes", optarg);
+
     return 0;
   case SHRPX_OPTID_CONF:
     LOG(WARN) << "conf: ignored";

src/shrpx_config.h

@@ -351,6 +351,8 @@ constexpr auto SHRPX_OPT_TLS_ANTI_REPLAY_MEMCACHED_PRIVATE_KEY_FILE =
     StringRef::from_lit("tls-anti-replay-memcached-private-key-file");
 constexpr auto SHRPX_OPT_TLS_ANTI_REPLAY_MEMCACHED_ADDRESS_FAMILY =
     StringRef::from_lit("tls-anti-replay-memcached-address-family");
+constexpr auto SHRPX_OPT_NO_STRIP_INCOMING_NGHTTPX_0RTT_UNIQ =
+    StringRef::from_lit("no-strip-incoming-nghttpx-0rtt-uniq");
 
 constexpr size_t SHRPX_OBFUSCATED_NODE_LENGTH = 8;
 
@@ -704,6 +706,9 @@ struct HttpConfig {
     bool add;
     bool strip_incoming;
   } xfp;
+  struct {
+    bool strip_incoming;
+  } zero_rtt_uniq;
   std::vector<AltSvc> altsvcs;
   std::vector<ErrorPage> error_pages;
   HeaderRefs add_request_headers;
@@ -1096,6 +1101,7 @@ enum {
   SHRPX_OPTID_NO_OCSP,
   SHRPX_OPTID_NO_SERVER_PUSH,
   SHRPX_OPTID_NO_SERVER_REWRITE,
+  SHRPX_OPTID_NO_STRIP_INCOMING_NGHTTPX_0RTT_UNIQ,
   SHRPX_OPTID_NO_STRIP_INCOMING_X_FORWARDED_PROTO,
   SHRPX_OPTID_NO_VERIFY_OCSP,
   SHRPX_OPTID_NO_VIA,

src/shrpx_connection.h

@@ -61,6 +61,8 @@ struct TLSConnection {
   DefaultPeekMemchunks rbuf;
   // Stores TLSv1.3 early data.
   DefaultMemchunks earlybuf;
+  // Message digest of ClientHello in hex string.
+  StringRef ch_hex_md;
   SSL *ssl;
   SSL_SESSION *cached_session;
   MemcachedRequest *cached_session_lookup_req;

src/shrpx_http2_downstream_connection.cc

@@ -271,7 +271,7 @@ int Http2DownstreamConnection::push_request_headers() {
     num_cookies = downstream_->count_crumble_request_cookie();
   }
 
-  // 9 means:
+  // 10 means:
   // 1. :method
   // 2. :scheme
   // 3. :path
@@ -281,8 +281,9 @@ int Http2DownstreamConnection::push_request_headers() {
   // 7. x-forwarded-proto (optional)
   // 8. te (optional)
   // 9. forwarded (optional)
+  // 10. nghttpx-0rtt-uniq (optional)
   auto nva = std::vector<nghttp2_nv>();
-  nva.reserve(req.fs.headers().size() + 9 + num_cookies +
+  nva.reserve(req.fs.headers().size() + 10 + num_cookies +
               httpconf.add_request_headers.size());
 
   nva.push_back(
@@ -311,11 +312,15 @@ int Http2DownstreamConnection::push_request_headers() {
   auto &fwdconf = httpconf.forwarded;
   auto &xffconf = httpconf.xff;
   auto &xfpconf = httpconf.xfp;
+  auto &zero_rtt_uniqconf = httpconf.zero_rtt_uniq;
 
   uint32_t build_flags =
       (fwdconf.strip_incoming ? http2::HDOP_STRIP_FORWARDED : 0) |
       (xffconf.strip_incoming ? http2::HDOP_STRIP_X_FORWARDED_FOR : 0) |
-      (xfpconf.strip_incoming ? http2::HDOP_STRIP_X_FORWARDED_PROTO : 0);
+      (xfpconf.strip_incoming ? http2::HDOP_STRIP_X_FORWARDED_PROTO : 0) |
+      (zero_rtt_uniqconf.strip_incoming
+           ? http2::HDOP_STRIP_NGHTTPX_ZERO_RTT_UNIQ
+           : 0);
 
   http2::copy_headers_to_nva_nocopy(nva, req.fs.headers(), build_flags);
 
@@ -326,6 +331,15 @@ int Http2DownstreamConnection::push_request_headers() {
   auto upstream = downstream_->get_upstream();
   auto handler = upstream->get_client_handler();
 
+#if OPENSSL_1_1_1_API
+  auto conn = handler->get_connection();
+
+  if (!SSL_is_init_finished(conn->tls.ssl)) {
+    nva.push_back(
+        http2::make_nv_ls_nocopy("nghttpx-0rtt-uniq", conn->tls.ch_hex_md));
+  }
+#endif // OPENSSL_1_1_1_API
+
   auto fwd =
       fwdconf.strip_incoming ? nullptr : req.fs.header(http2::HD_FORWARDED);
 

src/shrpx_http_downstream_connection.cc

@@ -535,11 +535,15 @@ int HttpDownstreamConnection::push_request_headers() {
   auto &fwdconf = httpconf.forwarded;
   auto &xffconf = httpconf.xff;
   auto &xfpconf = httpconf.xfp;
+  auto &zero_rtt_uniqconf = httpconf.zero_rtt_uniq;
 
   uint32_t build_flags =
       (fwdconf.strip_incoming ? http2::HDOP_STRIP_FORWARDED : 0) |
       (xffconf.strip_incoming ? http2::HDOP_STRIP_X_FORWARDED_FOR : 0) |
-      (xfpconf.strip_incoming ? http2::HDOP_STRIP_X_FORWARDED_PROTO : 0);
+      (xfpconf.strip_incoming ? http2::HDOP_STRIP_X_FORWARDED_PROTO : 0) |
+      (zero_rtt_uniqconf.strip_incoming
+           ? http2::HDOP_STRIP_NGHTTPX_ZERO_RTT_UNIQ
+           : 0);
 
   http2::build_http1_headers_from_headers(buf, req.fs.headers(), build_flags);
 
@@ -580,6 +584,16 @@ int HttpDownstreamConnection::push_request_headers() {
   auto upstream = downstream_->get_upstream();
   auto handler = upstream->get_client_handler();
 
+#if OPENSSL_1_1_1_API
+  auto conn = handler->get_connection();
+
+  if (!SSL_is_init_finished(conn->tls.ssl)) {
+    buf->append("Nghttpx-0rtt-uniq: ");
+    buf->append(conn->tls.ch_hex_md);
+    buf->append("\r\n");
+  }
+#endif // OPENSSL_1_1_1_API
+
   auto fwd =
       fwdconf.strip_incoming ? nullptr : req.fs.header(http2::HD_FORWARDED);
 

src/shrpx_tls.cc

@@ -580,7 +580,7 @@ int early_cb(SSL *ssl, int *al, void *arg) {
 
   auto &tlsconf = get_config()->tls;
 
-  auto hex_md =
+  conn->tls.ch_hex_md =
       util::format_hex(balloc, StringRef{std::begin(md), std::end(md)});
 
   if (tlsconf.anti_replay.memcached.host.empty()) {
@@ -590,7 +590,7 @@ int early_cb(SSL *ssl, int *al, void *arg) {
   auto req = make_unique<MemcachedRequest>();
   req->op = MEMCACHED_OP_ADD;
   req->key = MEMCACHED_ANTI_REPLY_KEY_PREFIX.str();
-  req->key += hex_md;
+  req->key += conn->tls.ch_hex_md;
 
   // TODO No value at the moment