MINOR: quic: refactor packet drop on reception

Sometimes, a packet is dropped on reception. Several goto statements are
used, mostly to increment a proxy drop counter or drop silently the
packet. However, this labels are interleaved. Re-arrang goto labels to
simplify this process :
* drop label is used to drop a packet with counter incrementation. This
  is the default method.
* drop_silent is the next label which does the same thing but skip the
  counter incrementation. This is useful when we do not need to report
  the packet dropping operation.

This should be backported up to 2.6.

diff --git a/src/quic_conn.c b/src/quic_conn.c
index f279501db2f3d15981555366f9caed89d95af662..7c77bfae0095e3014b88e2b0ece18b66a15e90a9 100644 (file)
--- a/src/quic_conn.c
+++ b/src/quic_conn.c
@@ -6056,7 +6056,7 @@ static int quic_rx_pkt_parse(struct quic_rx_packet *pkt,
        const unsigned char *beg = buf;
        struct proxy *prx;
        struct quic_counters *prx_counters;
-       int drop_no_conn = 0, long_header = 0;
+       int long_header = 0;
        uint32_t version;
        const struct quic_version *qv = NULL;
 
@@ -6083,7 +6083,7 @@ static int quic_rx_pkt_parse(struct quic_rx_packet *pkt,
                         * the remaining space.
                         */
                        pkt->len = end - buf;
-                       goto drop_no_conn;
+                       goto drop_silent;
                }
 
                TRACE_PROTO("Packet dropped", QUIC_EV_CONN_LPKT);
@@ -6105,12 +6105,8 @@ static int quic_rx_pkt_parse(struct quic_rx_packet *pkt,
                        goto drop;
                }
 
-               if (pkt->type == QUIC_PACKET_TYPE_0RTT && !l->bind_conf->ssl_conf.early_data) {
-                       TRACE_PROTO("0-RTT packet not supported", QUIC_EV_CONN_LPKT);
-                       drop_no_conn = 1;
-               }
-               else if (pkt->type == QUIC_PACKET_TYPE_INITIAL &&
-                        dgram->len < QUIC_INITIAL_PACKET_MINLEN) {
+               if (pkt->type == QUIC_PACKET_TYPE_INITIAL &&
+                   dgram->len < QUIC_INITIAL_PACKET_MINLEN) {
                        TRACE_PROTO("Too short datagram with an Initial packet", QUIC_EV_CONN_LPKT);
                        HA_ATOMIC_INC(&prx_counters->too_short_initial_dgram);
                        goto drop;
@@ -6138,11 +6134,11 @@ static int quic_rx_pkt_parse(struct quic_rx_packet *pkt,
                         /* unsupported version, send Negotiation packet */
                        if (send_version_negotiation(l->rx.fd, &dgram->saddr, pkt)) {
                                TRACE_ERROR("VN packet not sent", QUIC_EV_CONN_LPKT);
-                               goto err;
+                               goto drop_silent;
                        }
 
                        TRACE_PROTO("VN packet sent", QUIC_EV_CONN_LPKT);
-                       goto err;
+                       goto drop_silent;
                }
                pkt->version = qv;
 
@@ -6169,11 +6165,11 @@ static int quic_rx_pkt_parse(struct quic_rx_packet *pkt,
                                        if (send_retry(l->rx.fd, &dgram->saddr, pkt, qv)) {
                                                TRACE_PROTO("Error during Retry generation",
                                                            QUIC_EV_CONN_LPKT, NULL, NULL, NULL, qv);
-                                               goto err;
+                                               goto drop_silent;
                                        }
 
                                        HA_ATOMIC_INC(&prx_counters->retry_sent);
-                                       goto err;
+                                       goto drop_silent;
                                }
                        }
                        else if (!global.cluster_secret && token_len) {
@@ -6209,8 +6205,15 @@ static int quic_rx_pkt_parse(struct quic_rx_packet *pkt,
                 */
                pkt->pn_offset = buf - beg;
                pkt->len = pkt->pn_offset + len;
-               if (drop_no_conn)
-                       goto drop_no_conn;
+
+               /* Interrupt parsing after packet length retrieval : this
+                * ensures that only the packet is dropped but not the whole
+                * datagram.
+                */
+               if (pkt->type == QUIC_PACKET_TYPE_0RTT && !l->bind_conf->ssl_conf.early_data) {
+                       TRACE_PROTO("0-RTT packet not supported", QUIC_EV_CONN_LPKT);
+                       goto drop;
+               }
        }
        else {
                TRACE_PROTO("short header packet received", QUIC_EV_CONN_LPKT);
@@ -6242,17 +6245,9 @@ static int quic_rx_pkt_parse(struct quic_rx_packet *pkt,
        TRACE_LEAVE(QUIC_EV_CONN_LPKT, NULL, pkt, NULL, qv);
        return 0;
 
- drop_no_conn:
-       if (drop_no_conn)
-               HA_ATOMIC_INC(&prx_counters->dropped_pkt);
-       TRACE_LEAVE(QUIC_EV_CONN_LPKT, NULL, pkt);
-
-       return -1;
-
  drop:
        HA_ATOMIC_INC(&prx_counters->dropped_pkt);
-
- err:
+ drop_silent:
        if (!pkt->len)
                pkt->len = end - beg;
        TRACE_LEAVE(QUIC_EV_CONN_LPKT, NULL, pkt, NULL, qv);
@@ -6336,7 +6331,7 @@ static void qc_rx_pkt_handle(struct quic_conn *qc, struct quic_rx_packet *pkt,
                        TRACE_PROTO("Packet dropped",
                                    QUIC_EV_CONN_LPKT, qc, NULL, NULL, qv);
                        HA_ATOMIC_INC(&qc->prx_counters->dropped_pkt_bufoverrun);
-                       goto drop_no_conn;
+                       goto drop_silent;
                }
 
                /* Let us consume the remaining contiguous space. */
@@ -6349,7 +6344,7 @@ static void qc_rx_pkt_handle(struct quic_conn *qc, struct quic_rx_packet *pkt,
                        TRACE_PROTO("Too big packet",
                                    QUIC_EV_CONN_LPKT, qc, pkt, &pkt->len, qv);
                        HA_ATOMIC_INC(&qc->prx_counters->dropped_pkt_bufoverrun);
-                       goto drop_no_conn;
+                       goto drop_silent;
                }
        }
 
@@ -6365,7 +6360,7 @@ static void qc_rx_pkt_handle(struct quic_conn *qc, struct quic_rx_packet *pkt,
        *tasklist_head = tasklet_wakeup_after(*tasklist_head,
                                              qc->wait_event.tasklet);
 
- drop_no_conn:
+ drop_silent:
        TRACE_LEAVE(QUIC_EV_CONN_LPKT, qc ? qc : NULL, pkt, NULL, qv);
        return;