MINOR: quic: QUIC socket management finalization.

Implement ->accept_conn() callback for QUIC listener sockets.
Note that this patch also implements quic_session_accept() function
which is similar to session_accept_fd() without calling conn_complete_session()
at this time because we do not have any real QUIC mux.

src/quic_sock.c

@@ -17,6 +17,111 @@
 
 #include <haproxy/connection.h>
 #include <haproxy/listener.h>
+#include <haproxy/xprt_quic.h>
+
+/* This function is called from the protocol layer accept() in order to
+ * instantiate a new session on behalf of a given listener and frontend. It
+ * returns a positive value upon success, 0 if the connection can be ignored,
+ * or a negative value upon critical failure. The accepted connection is
+ * closed if we return <= 0. If no handshake is needed, it immediately tries
+ * to instantiate a new stream. The connection must already have been filled
+ * with the incoming connection handle (a fd), a target (the listener) and a
+ * source address.
+ */
+int quic_session_accept(struct connection *cli_conn)
+{
+	struct listener *l = __objt_listener(cli_conn->target);
+	struct proxy *p = l->bind_conf->frontend;
+	struct session *sess;
+
+	cli_conn->proxy_netns = l->rx.settings->netns;
+	conn_prepare(cli_conn, l->rx.proto, l->bind_conf->xprt);
+
+	/* This flag is ordinarily set by conn_ctrl_init() which cannot
+	 * be called for now.
+	 */
+	cli_conn->flags |= CO_FL_CTRL_READY;
+
+	/* wait for a PROXY protocol header */
+	if (l->options & LI_O_ACC_PROXY)
+		cli_conn->flags |= CO_FL_ACCEPT_PROXY;
+
+	/* wait for a NetScaler client IP insertion protocol header */
+	if (l->options & LI_O_ACC_CIP)
+		cli_conn->flags |= CO_FL_ACCEPT_CIP;
+
+	if (conn_xprt_init(cli_conn) < 0)
+		goto out_free_conn;
+
+	/* Add the handshake pseudo-XPRT */
+	if (cli_conn->flags & (CO_FL_ACCEPT_PROXY | CO_FL_ACCEPT_CIP)) {
+		if (xprt_add_hs(cli_conn) != 0)
+			goto out_free_conn;
+	}
+	sess = session_new(p, l, &cli_conn->obj_type);
+	if (!sess)
+		goto out_free_conn;
+
+	conn_set_owner(cli_conn, sess, NULL);
+
+	return 1;
+
+ out_free_sess:
+	/* prevent call to listener_release during session_free. It will be
+	* done below, for all errors. */
+	sess->listener = NULL;
+	session_free(sess);
+ out_free_conn:
+	cli_conn->qc->conn = NULL;
+	conn_stop_tracking(cli_conn);
+	conn_xprt_close(cli_conn);
+	conn_free(cli_conn);
+ out:
+
+	return 0;
+}
+
+/*
+ * Inspired from session_accept_fd().
+ * Instantiate a new connection (connection struct) to be attached to <qc>
+ * QUIC connection of <l> listener.
+ * Returns 1 if succeeded, 0 if not.
+ */
+static int new_quic_cli_conn(struct quic_conn *qc, struct listener *l,
+                             struct sockaddr_storage *saddr)
+{
+	struct connection *cli_conn;
+	struct sockaddr_storage *dst;
+
+	dst = NULL;
+	if (unlikely((cli_conn = conn_new(&l->obj_type)) == NULL))
+		goto out;
+
+	if (!sockaddr_alloc(&dst, saddr, sizeof *saddr))
+		goto out_free_conn;
+
+	qc->conn = cli_conn;
+	cli_conn->qc = qc;
+
+	cli_conn->dst = dst;
+	cli_conn->handle.fd = l->rx.fd;
+	cli_conn->flags |= CO_FL_ADDR_FROM_SET;
+	cli_conn->target = &l->obj_type;
+
+	/* XXX Should not be there. */
+	l->accept = quic_session_accept;
+
+	return 1;
+
+ out_free_conn:
+	conn_stop_tracking(cli_conn);
+	conn_xprt_close(cli_conn);
+	conn_free(cli_conn);
+	qc->conn = NULL;
+ out:
+
+	return 0;
+}
 
 /* Tests if the receiver supports accepting connections. Returns positive on
  * success, 0 if not possible
@@ -32,8 +137,54 @@ int quic_sock_accepting_conn(const struct receiver *rx)
  */
 struct connection *quic_sock_accept_conn(struct listener *l, int *status)
 {
-	/* TO DO */
-	return NULL;
+	struct quic_conn *qc;
+	struct quic_rx_packet *pkt;
+	struct quic_cid *odcid;
+	int ret, ipv4;
+
+	qc = NULL;
+	pkt = LIST_ELEM(l->rx.qpkts.n, struct quic_rx_packet *, rx_list);
+	/* Should never happen. */
+	if (&pkt->rx_list == &l->rx.qpkts)
+		goto err;
+
+	qc = pkt->qc;
+	LIST_DEL(&pkt->rx_list);
+	if (!new_quic_cli_conn(qc, l, &pkt->saddr))
+		goto err;
+
+	ipv4 = pkt->saddr.ss_family == AF_INET;
+	if (!qc_new_conn_init(qc, ipv4, &l->rx.odcids, &l->rx.cids,
+	                      pkt->dcid.data, pkt->dcid.len,
+	                      pkt->scid.data, pkt->scid.len))
+		goto err;
+
+	odcid = &qc->params.original_destination_connection_id;
+	/* Copy the transport parameters. */
+	qc->params = l->bind_conf->quic_params;
+	/* Copy original_destination_connection_id transport parameter. */
+	memcpy(odcid->data, &pkt->dcid, pkt->odcid_len);
+	odcid->len = pkt->odcid_len;
+	/* Copy the initial source connection ID. */
+	quic_cid_cpy(&qc->params.initial_source_connection_id, &qc->scid);
+	qc->enc_params_len =
+		quic_transport_params_encode(qc->enc_params,
+		                             qc->enc_params + sizeof qc->enc_params,
+		                             &qc->params, 1);
+	if (!qc->enc_params_len)
+		goto err;
+
+	ret = CO_AC_DONE;
+
+ done:
+	if (status)
+		*status = ret;
+
+	return qc ? qc->conn : NULL;
+
+ err:
+	ret = CO_AC_PAUSE;
+	goto done;
 }
 
 /* Function called on a read event from a listening socket. It tries
@@ -69,4 +220,5 @@ void quic_sock_fd_iocb(int fd)
 	} while (0);
 
 	buf->data = ret;
+	quic_lstnr_dgram_read(buf->area, buf->data, l, &saddr);
 }