MINOR: mux-quic: ensure CONNECTION_CLOSE is scheduled once per conn

Add BUG_ON() statements to ensure qcc_emit_cc()/qcc_emit_cc_app() is not
called more than one time for each connection. This should improve code
resilience of MUX-QUIC and H3 and it will ensure that a scheduled
CONNECTION_CLOSE is not overwritten by another one with a different
error code.

This commit relies on the previous one to ensure all QUIC operations are
not conducted as soon as a CONNECTION_CLOSE has been prepared :
  commit d7fbf458f8a4c5b09cbf0da0208fbad70caaca33
  MINOR: mux-quic: interrupt most operations if CONNECTION_CLOSE scheduled

This should be backported up to 2.7.

diff --git a/src/mux_quic.c b/src/mux_quic.c
index 945fd6d5f023e60fa7dd89b6176ca6863b64ff67..c67432391dea5824b65b50419a78524d60c268d8 100644 (file)
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -31,6 +31,9 @@ static void qcc_emit_cc(struct qcc *qcc, int err)
 {
        TRACE_ENTER(QMUX_EV_QCC_END, qcc->conn);
 
+       /* This function must not be called multiple times. */
+       BUG_ON(qcc->flags & QC_CF_CC_EMIT);
+
        TRACE_STATE("set CONNECTION_CLOSE on quic-conn", QMUX_EV_QCC_WAKE, qcc->conn);
        quic_set_connection_close(qcc->conn->handle.qc, quic_err_transport(err));
        qcc->flags |= QC_CF_CC_EMIT;
@@ -832,6 +835,9 @@ void qcc_emit_cc_app(struct qcc *qcc, int err, int immediate)
 {
        TRACE_ENTER(QMUX_EV_QCC_END, qcc->conn);
 
+       /* This function must not be called multiple times after immediate is set. */
+       BUG_ON(qcc->flags & QC_CF_CC_EMIT);
+
        if (immediate) {
                quic_set_connection_close(qcc->conn->handle.qc, quic_err_app(err));
                qcc->flags |= QC_CF_CC_EMIT;