MINOR: listener: Add QUIC info to listeners and receivers.

This patch adds a quic_transport_params struct to bind_conf struct
used for the listeners. This is to store the QUIC transport parameters
for the listeners. Also initializes them when calling str2listener().
Before str2sa_range() it's too early to figure we're going to speak QUIC,
and after it's too late as listeners are already created. So it seems that
doing it in str2listener() when the protocol is discovered is the best
place.

Also adds two ebtrees to the underlying receivers to store the connection
by connections IDs (one for the original connection IDs, and another
one for the definitive connection IDs which really identify the connections.

However it doesn't seem normal that it is stored in the receiver nor the
listener. There should be a private context in the listener so that
protocols can store internal information. This element should in
fact be the listener handle.

Something still feels wrong, and probably we'll have to make QUIC and
SSL co-exist: a proof of this is that there's some explicit code in
bind_parse_ssl() to prevent the "ssl" keyword from replacing the xprt.
diff --git a/include/haproxy/listener-t.h b/include/haproxy/listener-t.h
index ec57f88..ce5ed40 100644
--- a/include/haproxy/listener-t.h
+++ b/include/haproxy/listener-t.h
@@ -36,6 +36,7 @@
 #ifdef USE_OPENSSL
 #include <haproxy/openssl-compat.h>
 #endif
+#include <haproxy/xprt_quic-t.h>
 
 /* Some pointer types reference below */
 struct task;
@@ -166,6 +167,9 @@
 
 	struct cert_key_and_chain * ca_sign_ckch;	/* CA and possible certificate chain for ca generation */
 #endif
+#ifdef USE_QUIC
+	struct quic_transport_params quic_params; /* QUIC transport parameters. */
+#endif
 	struct proxy *frontend;    /* the frontend all these listeners belong to, or NULL */
 	const struct mux_proto_list *mux_proto; /* the mux to use for all incoming connections (specified by the "proto" keyword) */
 	struct xprt_ops *xprt;     /* transport-layer operations for all listeners */
diff --git a/include/haproxy/receiver-t.h b/include/haproxy/receiver-t.h
index 5b17211..7284da3 100644
--- a/include/haproxy/receiver-t.h
+++ b/include/haproxy/receiver-t.h
@@ -62,6 +62,11 @@
 	void (*iocb)(int fd);            /* generic I/O handler (typically accept callback) */
 	struct rx_settings *settings;    /* points to the settings used by this receiver */
 	struct list proto_list;          /* list in the protocol header */
+#ifdef USE_QUIC
+	struct list qpkts;               /* QUIC Initial packets to accept new connections */
+	struct eb_root odcids;           /* QUIC original destination connection IDs. */
+	struct eb_root cids;             /* QUIC connection IDs. */
+#endif
 	/* warning: this struct is huge, keep it at the bottom */
 	struct sockaddr_storage addr;    /* the address the socket is bound to */
 };
diff --git a/src/cfgparse.c b/src/cfgparse.c
index 957ae9e..4dd01bb 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -78,6 +78,7 @@
 #include <haproxy/time.h>
 #include <haproxy/tools.h>
 #include <haproxy/uri_auth-t.h>
+#include <haproxy/xprt_quic.h>
 
 
 /* Used to chain configuration sections definitions. This list
@@ -135,6 +136,17 @@
 			goto fail;
 
 		/* OK the address looks correct */
+
+#ifdef USE_QUIC
+		/* The transport layer automatically switches to QUIC when QUIC
+		 * is selected, regardless of bind_conf settings. We then need
+		 * to initialize QUIC params.
+		 */
+		if (proto->sock_type == SOCK_DGRAM && proto->ctrl_type == SOCK_STREAM) {
+			bind_conf->xprt = xprt_get(XPRT_QUIC);
+			quic_transport_params_init(&bind_conf->quic_params, 1);
+		}
+#endif
 		if (!create_listeners(bind_conf, ss2, port, end, fd, proto, err)) {
 			memprintf(err, "%s for address '%s'.\n", *err, str);
 			goto fail;
diff --git a/src/proto_quic.c b/src/proto_quic.c
index 751fc49..8b3e91b 100644
--- a/src/proto_quic.c
+++ b/src/proto_quic.c
@@ -46,6 +46,7 @@
 #include <haproxy/tools.h>
 
 
+static void quic_add_listener(struct protocol *proto, struct listener *listener);
 static int quic_bind_listener(struct listener *listener, char *errmsg, int errlen);
 static int quic_connect_server(struct connection *conn, int flags);
 static void quic_enable_listener(struct listener *listener);
@@ -60,7 +61,7 @@
 	.listen         = quic_bind_listener,
 	.enable         = quic_enable_listener,
 	.disable        = quic_disable_listener,
-	.add            = default_add_listener,
+	.add            = quic_add_listener,
 	.unbind         = default_unbind_listener,
 	.suspend        = default_suspend_listener,
 	.resume         = default_resume_listener,
@@ -97,7 +98,7 @@
 	.listen         = quic_bind_listener,
 	.enable         = quic_enable_listener,
 	.disable        = quic_disable_listener,
-	.add            = default_add_listener,
+	.add            = quic_add_listener,
 	.unbind         = default_unbind_listener,
 	.suspend        = default_suspend_listener,
 	.resume         = default_resume_listener,
@@ -513,6 +514,18 @@
 	return SF_ERR_NONE;  /* connection is OK */
 }
 
+/* Add listener <listener> to protocol <proto>. Technically speaking we just
+ * initialize a few entries which should be doable during quic_bind_listener().
+ * The end of the initialization goes on with the default function.
+ */
+static void quic_add_listener(struct protocol *proto, struct listener *listener)
+{
+	LIST_INIT(&listener->rx.qpkts);
+	listener->rx.odcids = EB_ROOT_UNIQUE;
+	listener->rx.cids = EB_ROOT_UNIQUE;
+	default_add_listener(proto, listener);
+}
+
 /* This function tries to bind a QUIC4/6 listener. It may return a warning or
  * an error message in <errmsg> if the message is at most <errlen> bytes long
  * (including '\0'). Note that <errmsg> may be NULL if <errlen> is also zero.