Release 2.26.0

- [OPTIMIZATION] Adjust packet reordering threshold when spurious losses
  are detected.
- [API] Pass pointer to local sockaddr to ea_get_ssl_ctx() callback.

Author: Dmitri Tikhonov

CHANGELOG

@@ -1,3 +1,9 @@
+2020-12-09
+    - 2.26.0
+    - [OPTIMIZATION] Adjust packet reordering threshold when spurious losses
+      are detected.
+    - [API] Pass pointer to local sockaddr to ea_get_ssl_ctx() callback.
+
 2020-12-04
     - 2.25.0
     - [API, FEATURE] Add es_delay_onclose option to delay on_close until all

bin/prog.c

@@ -39,7 +39,7 @@
 
 static int prog_stopped;
 
-static SSL_CTX * get_ssl_ctx (void *);
+static SSL_CTX * get_ssl_ctx (void *, const struct sockaddr *);
 
 static const struct lsquic_packout_mem_if pmi = {
     .pmi_allocate = pba_allocate,
@@ -417,7 +417,7 @@ prog_init_client (struct prog *prog)
 
 
 static SSL_CTX *
-get_ssl_ctx (void *peer_ctx)
+get_ssl_ctx (void *peer_ctx, const struct sockaddr *unused)
 {
     const struct service_port *const sport = peer_ctx;
     return sport->sp_prog->prog_ssl_ctx;

docs/apiref.rst

@@ -257,10 +257,10 @@ optional members.
 
         Look up certificate.  Mandatory in server mode.
 
-    .. member:: struct ssl_ctx_st *                (*ea_get_ssl_ctx)(void *peer_ctx)
+    .. member:: struct ssl_ctx_st *                (*ea_get_ssl_ctx)(void *peer_ctx, const struct sockaddr *local)
 
         Get SSL_CTX associated with a peer context.  Mandatory in server
-        mode.  This is use for default values for SSL instantiation.
+        mode.  This is used for default values for SSL instantiation.
 
     .. member:: const struct lsquic_hset_if         *ea_hsi_if
     .. member:: void                                *ea_hsi_ctx

docs/conf.py

@@ -24,9 +24,9 @@
 author = u'LiteSpeed Technologies'
 
 # The short X.Y version
-version = u'2.25'
+version = u'2.26'
 # The full version, including alpha/beta/rc tags
-release = u'2.25.0'
+release = u'2.26.0'
 
 
 # -- General configuration ---------------------------------------------------

docs/tutorial.rst

@@ -863,7 +863,8 @@ The server requires SSL callbacks to be present.  The basic required callback is
   struct lsquic_engine_api {
     lsquic_lookup_cert_f   ea_lookup_cert;
     void                  *ea_cert_lu_ctx;
-    struct ssl_ctx_st *  (*ea_get_ssl_ctx)(void *peer_ctx);
+    struct ssl_ctx_st *  (*ea_get_ssl_ctx)(void *peer_ctx,
+                                            const struct sockaddr *local);
     /* (Other members of the struct are not shown) */
   };
 

include/lsquic.h

@@ -24,7 +24,7 @@ extern "C" {
 #endif
 
 #define LSQUIC_MAJOR_VERSION 2
-#define LSQUIC_MINOR_VERSION 25
+#define LSQUIC_MINOR_VERSION 26
 #define LSQUIC_PATCH_VERSION 0
 
 /**
@@ -1274,7 +1274,8 @@ struct lsquic_engine_api
     lsquic_lookup_cert_f                 ea_lookup_cert;
     void                                *ea_cert_lu_ctx;
     /** Mandatory callback for server, optional for client. */
-    struct ssl_ctx_st *                (*ea_get_ssl_ctx)(void *peer_ctx);
+    struct ssl_ctx_st *                (*ea_get_ssl_ctx)(void *peer_ctx,
+                                                const struct sockaddr *local);
     /**
      * Shared hash interface is optional.  If set to zero, performance of
      * multiple LSQUIC instances will be degraded.

src/liblsquic/lsquic_enc_sess_ietf.c

@@ -888,11 +888,20 @@ iquic_esfi_create_client (const char *hostname,
         enc_sess->esi_alpn = am->alpn;
     }
 
-    if (enc_sess->esi_enpub->enp_get_ssl_ctx
-                && (ssl_ctx = enc_sess->esi_enpub->enp_get_ssl_ctx(peer_ctx)))
-        set_app_ctx = 1;
+    if (enc_sess->esi_enpub->enp_get_ssl_ctx)
+    {
+        struct network_path *const path =
+            enc_sess->esi_conn->cn_if->ci_get_path(enc_sess->esi_conn, NULL);
+        ssl_ctx = enc_sess->esi_enpub->enp_get_ssl_ctx(peer_ctx,
+                                                            NP_LOCAL_SA(path));
+        if (ssl_ctx)
+            set_app_ctx = 1;
+        else
+            goto create_new_ssl_ctx;
+    }
     else
     {
+  create_new_ssl_ctx:
         LSQ_DEBUG("Create new SSL_CTX");
         ssl_ctx = SSL_CTX_new(TLS_method());
         if (!ssl_ctx)
@@ -1363,6 +1372,7 @@ static int
 iquic_esfi_init_server (enc_session_t *enc_session_p)
 {
     struct enc_sess_iquic *const enc_sess = enc_session_p;
+    struct network_path *path;
     const struct alpn_map *am;
     unsigned quic_ctx_idx;
     int transpa_len;
@@ -1390,8 +1400,9 @@ iquic_esfi_init_server (enc_session_t *enc_session_p)
   ok:   enc_sess->esi_alpn = am->alpn;
     }
 
-    ssl_ctx = enc_sess->esi_enpub->enp_get_ssl_ctx(
-                    lsquic_conn_get_peer_ctx(enc_sess->esi_conn, NULL));
+    path = enc_sess->esi_conn->cn_if->ci_get_path(enc_sess->esi_conn, NULL);
+    ssl_ctx = enc_sess->esi_enpub->enp_get_ssl_ctx(path->np_peer_ctx,
+                                                            NP_LOCAL_SA(path));
     if (!ssl_ctx)
     {
         LSQ_ERROR("fetching SSL context associated with peer context failed");

src/liblsquic/lsquic_engine_public.h

@@ -20,6 +20,7 @@ struct ssl_ctx_st;
 struct crand;
 struct evp_aead_ctx_st;
 struct lsquic_server_config;
+struct sockaddr;
 
 enum warning_type
 {
@@ -37,7 +38,8 @@ struct lsquic_engine_public {
     struct token_generator         *enp_tokgen;
     lsquic_lookup_cert_f            enp_lookup_cert;
     void                           *enp_cert_lu_ctx;
-    struct ssl_ctx_st *           (*enp_get_ssl_ctx)(void *peer_ctx);
+    struct ssl_ctx_st *           (*enp_get_ssl_ctx)(void *peer_ctx,
+                                                     const struct sockaddr *);
     const struct lsquic_shared_hash_if
                                    *enp_shi;
     void                           *enp_shi_ctx;

src/liblsquic/lsquic_packet_out.h

@@ -166,6 +166,7 @@ typedef struct lsquic_packet_out
         POL_HEADER_PROT = 1 << 9,       /* Header protection applied */
 #endif
         POL_LIMITED     = 1 << 10,      /* Used to credit sc_next_limit if needed. */
+        POL_FACKED   = 1 << 11,         /* Lost due to FACK check */
     }                  po_lflags:16;
     unsigned char     *po_data;
 

src/liblsquic/lsquic_send_ctl.c

@@ -417,6 +417,13 @@ lsquic_send_ctl_init (lsquic_send_ctl_t *ctl, struct lsquic_alarmset *alset,
         ctl->sc_can_send = send_ctl_can_send_pre_hsk;
     else
         ctl->sc_can_send = send_ctl_can_send;
+    ctl->sc_reord_thresh = N_NACKS_BEFORE_RETX;
+#if LSQUIC_DEVEL
+    const char *s;
+    s = getenv("LSQUIC_DYN_PTHRESH");
+    if (s == NULL || atoi(s))
+        ctl->sc_flags |= SC_DYN_PTHRESH;
+#endif
 }
 
 
@@ -884,7 +891,7 @@ send_ctl_destroy_chain (struct lsquic_send_ctl *ctl,
 }
 
 
-static void
+static struct lsquic_packet_out *
 send_ctl_record_loss (struct lsquic_send_ctl *ctl,
                                         struct lsquic_packet_out *packet_out)
 {
@@ -909,16 +916,21 @@ send_ctl_record_loss (struct lsquic_send_ctl *ctl,
          * remove from the list:
          */
         TAILQ_INSERT_BEFORE(packet_out, loss_record, po_next);
+        return loss_record;
     }
     else
+    {
         LSQ_INFO("cannot allocate memory for loss record");
+        return NULL;
+    }
 }
 
 
-static int
+static struct lsquic_packet_out *
 send_ctl_handle_regular_lost_packet (struct lsquic_send_ctl *ctl,
             lsquic_packet_out_t *packet_out, struct lsquic_packet_out **next)
 {
+    struct lsquic_packet_out *loss_record;
     unsigned packet_sz;
 
     assert(ctl->sc_n_in_flight_all);
@@ -952,11 +964,11 @@ send_ctl_handle_regular_lost_packet (struct lsquic_send_ctl *ctl,
     {
         LSQ_DEBUG("lost retransmittable packet %"PRIu64,
                                                     packet_out->po_packno);
-        send_ctl_record_loss(ctl, packet_out);
+        loss_record = send_ctl_record_loss(ctl, packet_out);
         send_ctl_unacked_remove(ctl, packet_out, packet_sz);
         TAILQ_INSERT_TAIL(&ctl->sc_lost_packets, packet_out, po_next);
         packet_out->po_flags |= PO_LOST;
-        return 1;
+        return loss_record;
     }
     else
     {
@@ -965,7 +977,7 @@ send_ctl_handle_regular_lost_packet (struct lsquic_send_ctl *ctl,
         send_ctl_unacked_remove(ctl, packet_out, packet_sz);
         send_ctl_destroy_chain(ctl, packet_out, next);
         send_ctl_destroy_packet(ctl, packet_out);
-        return 0;
+        return NULL;
     }
 }
 
@@ -993,7 +1005,7 @@ send_ctl_handle_lost_packet (struct lsquic_send_ctl *ctl,
         struct lsquic_packet_out *packet_out, struct lsquic_packet_out **next)
 {
     if (0 == (packet_out->po_flags & PO_MTU_PROBE))
-        return send_ctl_handle_regular_lost_packet(ctl, packet_out, next);
+        return send_ctl_handle_regular_lost_packet(ctl, packet_out, next) != NULL;
     else
         return send_ctl_handle_lost_mtu_probe(ctl, packet_out);
 }
@@ -1031,7 +1043,7 @@ static int
 send_ctl_detect_losses (struct lsquic_send_ctl *ctl, enum packnum_space pns,
                                                             lsquic_time_t time)
 {
-    lsquic_packet_out_t *packet_out, *next;
+    struct lsquic_packet_out *packet_out, *next, *loss_record;
     lsquic_packno_t largest_retx_packno, largest_lost_packno;
 
     largest_retx_packno = largest_retx_packet_number(ctl, pns);
@@ -1047,14 +1059,22 @@ send_ctl_detect_losses (struct lsquic_send_ctl *ctl, enum packnum_space pns,
         if (packet_out->po_flags & (PO_LOSS_REC|PO_POISON))
             continue;
 
-        if (packet_out->po_packno + N_NACKS_BEFORE_RETX <
+        if (packet_out->po_packno + ctl->sc_reord_thresh <
                                                 ctl->sc_largest_acked_packno)
         {
-            LSQ_DEBUG("loss by FACK detected, packet %"PRIu64,
+            LSQ_DEBUG("loss by FACK detected (dist: %"PRIu64"), packet %"PRIu64,
+                ctl->sc_largest_acked_packno - packet_out->po_packno,
                                                     packet_out->po_packno);
             if (0 == (packet_out->po_flags & PO_MTU_PROBE))
+            {
                 largest_lost_packno = packet_out->po_packno;
-            (void) send_ctl_handle_lost_packet(ctl, packet_out, &next);
+                loss_record = send_ctl_handle_regular_lost_packet(ctl,
+                                                        packet_out, &next);
+                if (loss_record)
+                    loss_record->po_lflags |= POL_FACKED;
+            }
+            else
+                send_ctl_handle_lost_mtu_probe(ctl, packet_out);
             continue;
         }
 
@@ -1120,6 +1140,26 @@ send_ctl_mtu_probe_acked (struct lsquic_send_ctl *ctl,
 }
 
 
+static void
+send_ctl_maybe_increase_reord_thresh (struct lsquic_send_ctl *ctl,
+                            const struct lsquic_packet_out *loss_record,
+                            lsquic_packno_t prev_largest_acked)
+{
+#if LSQUIC_DEVEL
+    if (ctl->sc_flags & SC_DYN_PTHRESH)
+#endif
+    if ((loss_record->po_lflags & POL_FACKED)
+            && loss_record->po_packno + ctl->sc_reord_thresh
+                < prev_largest_acked)
+    {
+        ctl->sc_reord_thresh = prev_largest_acked - loss_record->po_packno;
+        LSQ_DEBUG("packet %"PRIu64" was a spurious loss by FACK, increase "
+            "reordering threshold to %u", loss_record->po_packno,
+            ctl->sc_reord_thresh);
+    }
+}
+
+
 int
 lsquic_send_ctl_got_ack (lsquic_send_ctl_t *ctl,
                          const struct ack_info *acki,
@@ -1129,6 +1169,7 @@ lsquic_send_ctl_got_ack (lsquic_send_ctl_t *ctl,
                                     &acki->ranges[ acki->n_ranges - 1 ];
     lsquic_packet_out_t *packet_out, *next;
     lsquic_packno_t smallest_unacked;
+    lsquic_packno_t prev_largest_acked;
     lsquic_packno_t ack2ed[2];
     unsigned packet_sz;
     int app_limited, losses_detected;
@@ -1190,6 +1231,7 @@ lsquic_send_ctl_got_ack (lsquic_send_ctl_t *ctl,
         ctl->sc_cur_rt_end = lsquic_senhist_largest(&ctl->sc_senhist);
     }
 
+    prev_largest_acked = ctl->sc_largest_acked_packno;
     do_rtt = 0, skip_checks = 0;
     app_limited = -1;
     do
@@ -1234,6 +1276,8 @@ lsquic_send_ctl_got_ack (lsquic_send_ctl_t *ctl,
                                                                     po_next);
                 LSQ_DEBUG("acking via loss record %"PRIu64,
                                                         packet_out->po_packno);
+                send_ctl_maybe_increase_reord_thresh(ctl, packet_out,
+                                                            prev_largest_acked);
 #if LSQUIC_CONN_STATS
                 ++ctl->sc_conn_pub->conn_stats->out.acked_via_loss;
 #endif