nghttpx: Add proxyproto to frontend option to accept PROXY protocol

Previously, global accept-proxy-protocol option enables PROXY protocol
support for all frontend listeners, but this was inflexible.  To fix
this issue, accept-proxy-protocol option is now deprecated, and
instead proxyproto parameter in frontend option enables PROXY protocol
support per frontend.

src/shrpx.cc

@@ -1694,6 +1694,10 @@ Connections:
               default.  Any  requests which come through  this address
               are replied with 200 HTTP status, without no body.
 
+              To  accept   PROXY  protocol   version  1   on  frontend
+              connection,  specify  "proxyproto" parameter.   This  is
+              disabled by default.
+
               Default: *,3000
   --backlog=<N>
               Set listen backlog size.
@@ -1718,8 +1722,6 @@ Connections:
               timeouts when connecting and  making CONNECT request can
               be     specified    by     --backend-read-timeout    and
               --backend-write-timeout options.
-  --accept-proxy-protocol
-              Accept PROXY protocol version 1 on frontend connection.
 
 Performance:
   -n, --workers=<N>

src/shrpx_client_handler.cc

@@ -413,7 +413,8 @@ ClientHandler::ClientHandler(Worker *worker, int fd, SSL *ssl,
 
   auto config = get_config();
 
-  if (config->conn.upstream.accept_proxy_protocol) {
+  if (faddr_->accept_proxy_protocol ||
+      config->conn.upstream.accept_proxy_protocol) {
     read_ = &ClientHandler::read_clear;
     write_ = &ClientHandler::noop;
     on_read_ = &ClientHandler::proxy_protocol_read;

src/shrpx_config.cc

@@ -677,6 +677,7 @@ int parse_memcached_connection_params(MemcachedConnectionParams &out,
 struct UpstreamParams {
   int alt_mode;
   bool tls;
+  bool proxyproto;
 };
 
 namespace {
@@ -705,6 +706,8 @@ int parse_upstream_params(UpstreamParams &out, const StringRef &src_params) {
         return -1;
       }
       out.alt_mode = ALTMODE_HEALTHMON;
+    } else if (util::strieq_l("proxyproto", param)) {
+      out.proxyproto = true;
     } else if (!param.empty()) {
       LOG(ERROR) << "frontend: " << param << ": unknown keyword";
       return -1;
@@ -2091,6 +2094,7 @@ int parse_config(Config *config, int optid, const StringRef &opt,
     addr.fd = -1;
     addr.tls = params.tls;
     addr.alt_mode = params.alt_mode;
+    addr.accept_proxy_protocol = params.proxyproto;
 
     if (addr.alt_mode == ALTMODE_API) {
       apiconf.enabled = true;
@@ -2883,6 +2887,8 @@ int parse_config(Config *config, int optid, const StringRef &opt,
 #endif // !HAVE_MRUBY
     return 0;
   case SHRPX_OPTID_ACCEPT_PROXY_PROTOCOL:
+    LOG(WARN) << opt << ": deprecated.  Use proxyproto keyword in "
+              << SHRPX_OPT_FRONTEND << " instead.";
     config->conn.upstream.accept_proxy_protocol = util::strieq_l("yes", optarg);
 
     return 0;

src/shrpx_config.h

@@ -382,6 +382,8 @@ struct UpstreamAddr {
   bool host_unix;
   // true if TLS is enabled.
   bool tls;
+  // true if client is supposed to send PROXY protocol v1 header.
+  bool accept_proxy_protocol;
   int fd;
 };
 
@@ -775,6 +777,7 @@ struct ConnectionConfig {
       RateLimitConfig write;
     } ratelimit;
     size_t worker_connections;
+    // Deprecated.  See UpstreamAddr.accept_proxy_protocol.
     bool accept_proxy_protocol;
   } upstream;