BUG/MINOR: quic: handle Tx packet allocation failure properly

qc_prep_app_pkts() is responsible to built several new packets for
sending. It can fail due to memory allocation error. Before this patch,
the Tx buffer was released on error even if some packets were properly
generated.

With this patch, if an error happens on qc_prep_app_pkts(), we still try
to send already built packets if Tx buffer is not empty. The sending
loop is then interrupted and the Tx buffer is released with data
cleared.

This should be backported up to 2.7.

diff --git a/src/quic_conn.c b/src/quic_conn.c
index 65c5604ed17698a403316a28f7a180244ac944b7..daa687322c44720b0d3b86348388026ceb2d2167 100644 (file)
--- a/src/quic_conn.c
+++ b/src/quic_conn.c
@@ -4724,7 +4724,7 @@ static int qc_purge_txbuf(struct quic_conn *qc, struct buffer *buf)
  */
 static int qc_send_app_pkts(struct quic_conn *qc, struct list *frms)
 {
-       int status = 0;
+       int status = 0, ret;
        struct buffer *buf;
 
        TRACE_ENTER(QUIC_EV_CONN_TXPKT, qc);
@@ -4739,8 +4739,7 @@ static int qc_send_app_pkts(struct quic_conn *qc, struct list *frms)
                goto err;
 
        /* Prepare and send packets until we could not further prepare packets. */
-       while (1) {
-               int ret;
+       do {
                /* Currently buf cannot be non-empty at this stage. Even if a
                 * previous sendto() has failed it is emptied to simulate
                 * packet emission and rely on QUIC lost detection to try to
@@ -4750,23 +4749,19 @@ static int qc_send_app_pkts(struct quic_conn *qc, struct list *frms)
                b_reset(buf);
 
                ret = qc_prep_app_pkts(qc, buf, frms);
-               if (ret == -1) {
-                       qc_txb_release(qc);
-                       goto err;
-               }
-
-               if (!ret)
-                       break;
 
-               if (!qc_send_ppkts(buf, qc->xprt_ctx)) {
+               if (b_data(buf) && !qc_send_ppkts(buf, qc->xprt_ctx)) {
                        if (qc->flags & QUIC_FL_CONN_TO_KILL)
                                qc_txb_release(qc);
                        goto err;
                }
-       }
+       } while (ret > 0);
 
-       status = 1;
        qc_txb_release(qc);
+       if (ret < 0)
+               goto err;
+
+       status = 1;
        TRACE_LEAVE(QUIC_EV_CONN_TXPKT, qc);
        return status;
 
@@ -8142,7 +8137,7 @@ static struct quic_tx_packet *qc_build_pkt(unsigned char **pos,
 
        quic_packet_encrypt(payload, payload_len, first_byte, aad_len, pn, tls_ctx, qc, &encrypt_failure);
        if (encrypt_failure) {
-               /* TODO Unrecoverable failure, what to do of unencrypted input data ? */
+               /* TODO Unrecoverable failure, unencrypted data should be returned to the caller. */
                WARN_ON("quic_packet_encrypt failure");
                *err = -2;
                goto err;
@@ -8152,7 +8147,7 @@ static struct quic_tx_packet *qc_build_pkt(unsigned char **pos,
        pkt->len += QUIC_TLS_TAG_LEN;
        quic_apply_header_protection(qc, first_byte, buf_pn, pn_len, tls_ctx, &encrypt_failure);
        if (encrypt_failure) {
-               /* TODO Unrecoverable failure, what to do of unencrypted input data ? */
+               /* TODO Unrecoverable failure, unencrypted data should be returned to the caller. */
                WARN_ON("quic_apply_header_protection failure");
                *err = -2;
                goto err;