HTTP/3: refactored dynamic table implementation.

Previously dynamic table was not functional because of zero limit on its size
set by default.  Now the following changes enable it:

- new directives to set SETTINGS_QPACK_MAX_TABLE_CAPACITY and
  SETTINGS_QPACK_BLOCKED_STREAMS
- send settings with SETTINGS_QPACK_MAX_TABLE_CAPACITY and
  SETTINGS_QPACK_BLOCKED_STREAMS to the client
- send Insert Count Increment to the client
- send Header Acknowledgement to the client
- evict old dynamic table entries on overflow
- decode Required Insert Count from client
- block stream if Required Insert Count is not reached

7 files changed, 584 insertions, 166 deletions

diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index ac5937347..89e554bf2 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -223,7 +223,17 @@ ngx_http_init_connection(ngx_connection_t *c)
 
 #if (NGX_HTTP_V3)
     if (c->type == SOCK_DGRAM) {
-        hc = ngx_pcalloc(c->pool, sizeof(ngx_http_v3_connection_t));
+        ngx_http_v3_connection_t  *h3c;
+
+        h3c = ngx_pcalloc(c->pool, sizeof(ngx_http_v3_connection_t));
+        if (h3c == NULL) {
+            ngx_http_close_connection(c);
+            return;
+        }
+
+        ngx_queue_init(&h3c->blocked);
+
+        hc = &h3c->hc;
         hc->quic = 1;
         hc->ssl = 1;
 
@@ -414,6 +424,13 @@ ngx_http_quic_stream_handler(ngx_connection_t *c)
     pc = c->qs->parent;
     h3c = pc->data;
 
+    if (!h3c->settings_sent) {
+        h3c->settings_sent = 1;
+
+        /* TODO close QUIC connection on error */
+        (void) ngx_http_v3_send_settings(c);
+    }
+
     if (c->qs->id & NGX_QUIC_STREAM_UNIDIRECTIONAL) {
         ngx_http_v3_handle_client_uni_stream(c);
         return;
@@ -1255,7 +1272,7 @@ ngx_http_process_request_line(ngx_event_t *rev)
             break;
         }
 
-        if (rc == NGX_DONE) {
+        if (rc == NGX_BUSY) {
             if (ngx_handle_read_event(rev, 0) != NGX_OK) {
                 ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                 return;
diff --git a/src/http/v3/ngx_http_v3.h b/src/http/v3/ngx_http_v3.h
index d48f13922..b51febcdd 100644
--- a/src/http/v3/ngx_http_v3.h
+++ b/src/http/v3/ngx_http_v3.h
@@ -48,32 +48,48 @@
 #define NGX_HTTP_V3_MAX_KNOWN_STREAM               6
 
 #define NGX_HTTP_V3_DEFAULT_MAX_FIELD_SIZE         4096
+#define NGX_HTTP_V3_DEFAULT_MAX_TABLE_CAPACITY     16384
+#define NGX_HTTP_V3_DEFAULT_MAX_BLOCKED_STREAMS    16
+
+
+#define ngx_http_v3_get_module_srv_conf(c, module)                            \
+    ngx_http_get_module_srv_conf(                                             \
+             ((ngx_http_v3_connection_t *) c->qs->parent->data)->hc.conf_ctx, \
+             module)
 
 
 typedef struct {
-    ngx_quic_tp_t           quic;
-    size_t                  max_field_size;
+    ngx_quic_tp_t                 quic;
+    size_t                        max_field_size;
+    size_t                        max_table_capacity;
+    ngx_uint_t                    max_blocked_streams;
 } ngx_http_v3_srv_conf_t;
 
 
 typedef struct {
-    ngx_http_connection_t   hc;
-
-    ngx_array_t            *dynamic;
-    ngx_connection_t       *known_streams[NGX_HTTP_V3_MAX_KNOWN_STREAM];
-} ngx_http_v3_connection_t;
+    ngx_str_t                     name;
+    ngx_str_t                     value;
+} ngx_http_v3_header_t;
 
 
-#define ngx_http_v3_get_module_srv_conf(c, module)                            \
-    ngx_http_get_module_srv_conf(                                             \
-             ((ngx_http_v3_connection_t *) c->qs->parent->data)->hc.conf_ctx, \
-             module)
+typedef struct {
+    ngx_http_v3_header_t        **elts;
+    ngx_uint_t                    nelts;
+    ngx_uint_t                    base;
+    size_t                        size;
+    size_t                        capacity;
+} ngx_http_v3_dynamic_table_t;
 
 
 typedef struct {
-    ngx_str_t               name;
-    ngx_str_t               value;
-} ngx_http_v3_header_t;
+    ngx_http_connection_t         hc;
+    ngx_http_v3_dynamic_table_t   table;
+    ngx_queue_t                   blocked;
+    ngx_uint_t                    nblocked;
+    ngx_uint_t                    settings_sent;
+                                               /* unsigned  settings_sent:1; */
+    ngx_connection_t             *known_streams[NGX_HTTP_V3_MAX_KNOWN_STREAM];
+} ngx_http_v3_connection_t;
 
 
 ngx_int_t ngx_http_v3_parse_request(ngx_http_request_t *r, ngx_buf_t *b);
@@ -88,6 +104,7 @@ uintptr_t ngx_http_v3_encode_varlen_int(u_char *p, uint64_t value);
 uintptr_t ngx_http_v3_encode_prefix_int(u_char *p, uint64_t value,
     ngx_uint_t prefix);
 
+ngx_int_t ngx_http_v3_send_settings(ngx_connection_t *c);
 void ngx_http_v3_handle_client_uni_stream(ngx_connection_t *c);
 
 ngx_int_t ngx_http_v3_ref_insert(ngx_connection_t *c, ngx_uint_t dynamic,
@@ -99,8 +116,12 @@ ngx_int_t ngx_http_v3_duplicate(ngx_connection_t *c, ngx_uint_t index);
 ngx_int_t ngx_http_v3_ack_header(ngx_connection_t *c, ngx_uint_t stream_id);
 ngx_int_t ngx_http_v3_cancel_stream(ngx_connection_t *c, ngx_uint_t stream_id);
 ngx_int_t ngx_http_v3_inc_insert_count(ngx_connection_t *c, ngx_uint_t inc);
-ngx_http_v3_header_t *ngx_http_v3_lookup_table(ngx_connection_t *c,
-    ngx_uint_t dynamic, ngx_uint_t index);
+ngx_int_t ngx_http_v3_lookup_static(ngx_connection_t *c, ngx_uint_t index,
+    ngx_str_t *name, ngx_str_t *value);
+ngx_int_t ngx_http_v3_lookup(ngx_connection_t *c, ngx_uint_t index,
+    ngx_str_t *name, ngx_str_t *value);
+ngx_int_t ngx_http_v3_decode_insert_count(ngx_connection_t *c,
+    ngx_uint_t *insert_count);
 ngx_int_t ngx_http_v3_check_insert_count(ngx_connection_t *c,
     ngx_uint_t insert_count);
 ngx_int_t ngx_http_v3_set_param(ngx_connection_t *c, uint64_t id,
diff --git a/src/http/v3/ngx_http_v3_module.c b/src/http/v3/ngx_http_v3_module.c
index 17029934e..386209cb7 100644
--- a/src/http/v3/ngx_http_v3_module.c
+++ b/src/http/v3/ngx_http_v3_module.c
@@ -125,6 +125,20 @@ static ngx_command_t  ngx_http_v3_commands[] = {
       offsetof(ngx_http_v3_srv_conf_t, max_field_size),
       NULL },
 
+    { ngx_string("http3_max_table_capacity"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_size_slot,
+      NGX_HTTP_SRV_CONF_OFFSET,
+      offsetof(ngx_http_v3_srv_conf_t, max_table_capacity),
+      NULL },
+
+    { ngx_string("http3_max_blocked_streams"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_num_slot,
+      NGX_HTTP_SRV_CONF_OFFSET,
+      offsetof(ngx_http_v3_srv_conf_t, max_blocked_streams),
+      NULL },
+
       ngx_null_command
 };
 
@@ -276,6 +290,8 @@ ngx_http_v3_create_srv_conf(ngx_conf_t *cf)
     v3cf->quic.retry = NGX_CONF_UNSET;
 
     v3cf->max_field_size = NGX_CONF_UNSET_SIZE;
+    v3cf->max_table_capacity = NGX_CONF_UNSET_SIZE;
+    v3cf->max_blocked_streams = NGX_CONF_UNSET_UINT;
 
     return v3cf;
 }
@@ -342,6 +358,14 @@ ngx_http_v3_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
                               prev->max_field_size,
                               NGX_HTTP_V3_DEFAULT_MAX_FIELD_SIZE);
 
+    ngx_conf_merge_size_value(conf->max_table_capacity,
+                              prev->max_table_capacity,
+                              NGX_HTTP_V3_DEFAULT_MAX_TABLE_CAPACITY);
+
+    ngx_conf_merge_uint_value(conf->max_blocked_streams,
+                              prev->max_blocked_streams,
+                              NGX_HTTP_V3_DEFAULT_MAX_BLOCKED_STREAMS);
+
     return NGX_CONF_OK;
 }
 
diff --git a/src/http/v3/ngx_http_v3_parse.c b/src/http/v3/ngx_http_v3_parse.c
index 85491082e..bd91c5b02 100644
--- a/src/http/v3/ngx_http_v3_parse.c
+++ b/src/http/v3/ngx_http_v3_parse.c
@@ -10,6 +10,10 @@
 #include <ngx_http.h>
 
 
+static ngx_int_t ngx_http_v3_parse_lookup(ngx_connection_t *c,
+    ngx_uint_t dynamic, ngx_uint_t index, ngx_str_t *name, ngx_str_t *value);
+
+
 ngx_int_t
 ngx_http_v3_parse_varlen_int(ngx_connection_t *c,
     ngx_http_v3_parse_varlen_int_t *st, u_char ch)
@@ -144,6 +148,7 @@ ngx_http_v3_parse_headers(ngx_connection_t *c, ngx_http_v3_parse_headers_t *st,
         sw_start = 0,
         sw_length,
         sw_prefix,
+        sw_verify,
         sw_header_rep,
         sw_done
     };
@@ -195,9 +200,20 @@ ngx_http_v3_parse_headers(ngx_connection_t *c, ngx_http_v3_parse_headers_t *st,
             return NGX_ERROR;
         }
 
-        st->state = sw_header_rep;
+        st->state = sw_verify;
         break;
 
+    case sw_verify:
+
+        rc = ngx_http_v3_check_insert_count(c, st->prefix.insert_count);
+        if (rc != NGX_OK) {
+            return rc;
+        }
+
+        st->state = sw_header_rep;
+
+        /* fall through */
+
     case sw_header_rep:
 
         rc = ngx_http_v3_parse_header_rep(c, &st->header_rep, st->prefix.base,
@@ -228,6 +244,12 @@ done:
 
     ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http3 parse headers done");
 
+    if (st->prefix.insert_count > 0) {
+        if (ngx_http_v3_client_ack_header(c, c->qs->id) != NGX_OK) {
+            return NGX_ERROR;
+        }
+    }
+
     st->state = sw_start;
     return NGX_DONE;
 }
@@ -286,6 +308,10 @@ ngx_http_v3_parse_header_block_prefix(ngx_connection_t *c,
 
 done:
 
+    if (ngx_http_v3_decode_insert_count(c, &st->insert_count) != NGX_OK) {
+        return NGX_ERROR;
+    }
+
     if (st->sign) {
         st->base = st->insert_count - st->delta_base - 1;
     } else {
@@ -294,7 +320,7 @@ done:
 
     ngx_log_debug4(NGX_LOG_DEBUG_HTTP, c->log, 0,
                   "http3 parse header block prefix done "
-                  "i:%ui, s:%ui, d:%ui, base:%uL",
+                  "insert_count:%ui, sign:%ui, delta_base:%ui, base:%uL",
                   st->insert_count, st->sign, st->delta_base, st->base);
 
     st->state = sw_start;
@@ -479,7 +505,6 @@ ngx_int_t
 ngx_http_v3_parse_header_ri(ngx_connection_t *c, ngx_http_v3_parse_header_t *st,
     u_char ch)
 {
-    ngx_http_v3_header_t  *h;
     enum {
         sw_start = 0,
         sw_index
@@ -518,15 +543,14 @@ done:
         st->index = st->base - st->index - 1;
     }
 
-    h = ngx_http_v3_lookup_table(c, st->dynamic, st->index);
-    if (h == NULL) {
+    if (ngx_http_v3_parse_lookup(c, st->dynamic, st->index, &st->name,
+                                 &st->value)
+        != NGX_OK)
+    {
         return NGX_ERROR;
     }
 
-    st->name = h->name;
-    st->value = h->value;
     st->state = sw_start;
-
     return NGX_DONE;
 }
 
@@ -535,8 +559,7 @@ ngx_int_t
 ngx_http_v3_parse_header_lri(ngx_connection_t *c,
     ngx_http_v3_parse_header_t *st, u_char ch)
 {
-    ngx_int_t              rc;
-    ngx_http_v3_header_t  *h;
+    ngx_int_t  rc;
     enum {
         sw_start = 0,
         sw_index,
@@ -616,12 +639,12 @@ done:
         st->index = st->base - st->index - 1;
     }
 
-    h = ngx_http_v3_lookup_table(c, st->dynamic, st->index);
-    if (h == NULL) {
+    if (ngx_http_v3_parse_lookup(c, st->dynamic, st->index, &st->name, NULL)
+        != NGX_OK)
+    {
         return NGX_ERROR;
     }
 
-    st->name = h->name;
     st->state = sw_start;
     return NGX_DONE;
 }
@@ -735,7 +758,6 @@ ngx_int_t
 ngx_http_v3_parse_header_pbi(ngx_connection_t *c,
     ngx_http_v3_parse_header_t *st, u_char ch)
 {
-    ngx_http_v3_header_t  *h;
     enum {
         sw_start = 0,
         sw_index
@@ -768,13 +790,13 @@ done:
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                    "http3 parse header pbi done dynamic[+%ui]", st->index);
 
-    h = ngx_http_v3_lookup_table(c, 1, st->base + st->index);
-    if (h == NULL) {
+    if (ngx_http_v3_parse_lookup(c, 1, st->base + st->index, &st->name,
+                                 &st->value)
+        != NGX_OK)
+    {
         return NGX_ERROR;
     }
 
-    st->name = h->name;
-    st->value = h->value;
     st->state = sw_start;
     return NGX_DONE;
 }
@@ -784,8 +806,7 @@ ngx_int_t
 ngx_http_v3_parse_header_lpbi(ngx_connection_t *c,
     ngx_http_v3_parse_header_t *st, u_char ch)
 {
-    ngx_int_t              rc;
-    ngx_http_v3_header_t  *h;
+    ngx_int_t  rc;
     enum {
         sw_start = 0,
         sw_index,
@@ -860,17 +881,57 @@ done:
                    "http3 parse header lpbi done dynamic[+%ui] \"%V\"",
                    st->index, &st->value);
 
-    h = ngx_http_v3_lookup_table(c, 1, st->base + st->index);
-    if (h == NULL) {
+    if (ngx_http_v3_parse_lookup(c, 1, st->base + st->index, &st->name, NULL)
+        != NGX_OK)
+    {
         return NGX_ERROR;
     }
 
-    st->name = h->name;
     st->state = sw_start;
     return NGX_DONE;
 }
 
 
+static ngx_int_t
+ngx_http_v3_parse_lookup(ngx_connection_t *c, ngx_uint_t dynamic,
+    ngx_uint_t index, ngx_str_t *name, ngx_str_t *value)
+{
+    u_char  *p;
+
+    if (!dynamic) {
+        return ngx_http_v3_lookup_static(c, index, name, value);
+    }
+
+    if (ngx_http_v3_lookup(c, index, name, value) != NGX_OK) {
+        return NGX_ERROR;
+    }
+
+    if (name) {
+        p = ngx_pnalloc(c->pool, name->len + 1);
+        if (p == NULL) {
+            return NGX_ERROR;
+        }
+
+        ngx_memcpy(p, name->data, name->len);
+        p[name->len] = '\0';
+        name->data = p;
+    }
+
+    if (value) {
+        p = ngx_pnalloc(c->pool, value->len + 1);
+        if (p == NULL) {
+            return NGX_ERROR;
+        }
+
+        ngx_memcpy(p, value->data, value->len);
+        p[value->len] = '\0';
+        value->data = p;
+    }
+
+    return NGX_OK;
+}
+
+
 ngx_int_t
 ngx_http_v3_parse_control(ngx_connection_t *c, void *data, u_char ch)
 {
@@ -1145,7 +1206,7 @@ done:
                    "http3 parse encoder instruction done");
 
     st->state = sw_start;
-    return NGX_DONE;
+    return NGX_AGAIN;
 }
 
 
@@ -1429,7 +1490,7 @@ done:
                    "http3 parse decoder instruction done");
 
     st->state = sw_start;
-    return NGX_DONE;
+    return NGX_AGAIN;
 }
 
 
diff --git a/src/http/v3/ngx_http_v3_request.c b/src/http/v3/ngx_http_v3_request.c
index 5747c8ee6..ae65ba9ea 100644
--- a/src/http/v3/ngx_http_v3_request.c
+++ b/src/http/v3/ngx_http_v3_request.c
@@ -64,12 +64,18 @@ ngx_http_v3_parse_request(ngx_http_request_t *r, ngx_buf_t *b)
     }
 
     while (b->pos < b->last) {
-        rc = ngx_http_v3_parse_headers(c, st, *b->pos++);
+        rc = ngx_http_v3_parse_headers(c, st, *b->pos);
 
         if (rc == NGX_ERROR) {
             goto failed;
         }
 
+        if (rc == NGX_BUSY) {
+            return NGX_BUSY;
+        }
+
+        b->pos++;
+
         if (rc == NGX_AGAIN) {
             continue;
         }
diff --git a/src/http/v3/ngx_http_v3_streams.c b/src/http/v3/ngx_http_v3_streams.c
index bd4583998..229ce5bf4 100644
--- a/src/http/v3/ngx_http_v3_streams.c
+++ b/src/http/v3/ngx_http_v3_streams.c
@@ -34,10 +34,6 @@ ngx_http_v3_handle_client_uni_stream(ngx_connection_t *c)
 {
     ngx_http_v3_uni_stream_t  *us;
 
-    ngx_http_v3_get_uni_stream(c, NGX_HTTP_V3_STREAM_CONTROL);
-    ngx_http_v3_get_uni_stream(c, NGX_HTTP_V3_STREAM_ENCODER);
-    ngx_http_v3_get_uni_stream(c, NGX_HTTP_V3_STREAM_DECODER);
-
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                    "http3 new uni stream id:0x%uxL", c->qs->id);
 
@@ -341,6 +337,56 @@ failed:
 
 
 ngx_int_t
+ngx_http_v3_send_settings(ngx_connection_t *c)
+{
+    u_char                    *p, buf[NGX_HTTP_V3_VARLEN_INT_LEN * 6];
+    size_t                     n;
+    ngx_connection_t          *cc;
+    ngx_http_v3_srv_conf_t    *v3cf;
+    ngx_http_v3_connection_t  *h3c;
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http3 send settings");
+
+    cc = ngx_http_v3_get_uni_stream(c, NGX_HTTP_V3_STREAM_CONTROL);
+    if (cc == NULL) {
+        return NGX_ERROR;
+    }
+
+    h3c = c->qs->parent->data;
+    v3cf = ngx_http_get_module_srv_conf(h3c->hc.conf_ctx, ngx_http_v3_module);
+
+    n = ngx_http_v3_encode_varlen_int(NULL,
+                                      NGX_HTTP_V3_PARAM_MAX_TABLE_CAPACITY);
+    n += ngx_http_v3_encode_varlen_int(NULL, v3cf->max_table_capacity);
+    n += ngx_http_v3_encode_varlen_int(NULL, NGX_HTTP_V3_PARAM_BLOCKED_STREAMS);
+    n += ngx_http_v3_encode_varlen_int(NULL, v3cf->max_blocked_streams);
+
+    p = (u_char *) ngx_http_v3_encode_varlen_int(buf,
+                                                 NGX_HTTP_V3_FRAME_SETTINGS);
+    p = (u_char *) ngx_http_v3_encode_varlen_int(p, n);
+    p = (u_char *) ngx_http_v3_encode_varlen_int(p,
+                                         NGX_HTTP_V3_PARAM_MAX_TABLE_CAPACITY);
+    p = (u_char *) ngx_http_v3_encode_varlen_int(p, v3cf->max_table_capacity);
+    p = (u_char *) ngx_http_v3_encode_varlen_int(p,
+                                            NGX_HTTP_V3_PARAM_BLOCKED_STREAMS);
+    p = (u_char *) ngx_http_v3_encode_varlen_int(p, v3cf->max_blocked_streams);
+    n = p - buf;
+
+    if (cc->send(cc, buf, n) != (ssize_t) n) {
+        goto failed;
+    }
+
+    return NGX_OK;
+
+failed:
+
+    ngx_http_v3_close_uni_stream(cc);
+
+    return NGX_ERROR;
+}
+
+
+ngx_int_t
 ngx_http_v3_client_ref_insert(ngx_connection_t *c, ngx_uint_t dynamic,
     ngx_uint_t index, ngx_str_t *value)
 {
diff --git a/src/http/v3/ngx_http_v3_tables.c b/src/http/v3/ngx_http_v3_tables.c
index ecebe943c..a57eccb9f 100644
--- a/src/http/v3/ngx_http_v3_tables.c
+++ b/src/http/v3/ngx_http_v3_tables.c
@@ -10,10 +10,22 @@
 #include <ngx_http.h>
 
 
-static ngx_array_t *ngx_http_v3_get_dynamic_table(ngx_connection_t *c);
+#define ngx_http_v3_table_entry_size(n, v) ((n)->len + (v)->len + 32)
+
+
+static ngx_int_t ngx_http_v3_evict(ngx_connection_t *c, size_t need);
+static void ngx_http_v3_cleanup_table(void *data);
+static void ngx_http_v3_unblock(void *data);
 static ngx_int_t ngx_http_v3_new_header(ngx_connection_t *c);
 
 
+typedef struct {
+    ngx_queue_t        queue;
+    ngx_connection_t  *connection;
+    ngx_uint_t        *nblocked;
+} ngx_http_v3_block_t;
+
+
 static ngx_http_v3_header_t  ngx_http_v3_static_table[] = {
 
     { ngx_string(":authority"),            ngx_string("") },
@@ -148,40 +160,73 @@ ngx_int_t
 ngx_http_v3_ref_insert(ngx_connection_t *c, ngx_uint_t dynamic,
     ngx_uint_t index, ngx_str_t *value)
 {
-    ngx_array_t           *dt;
-    ngx_connection_t      *pc;
-    ngx_http_v3_header_t  *ref, *h;
+    ngx_str_t  name;
 
-    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
-                   "http3 ref insert %s[$ui] \"%V\"",
-                   dynamic ? "dynamic" : "static", index, value);
+    if (dynamic) {
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                       "http3 ref insert dynamic[%ui] \"%V\"", index, value);
 
-    pc = c->qs->parent;
+        if (ngx_http_v3_lookup(c, index, &name, NULL) != NGX_OK) {
+            return NGX_ERROR;
+        }
 
-    ref = ngx_http_v3_lookup_table(c, dynamic, index);
-    if (ref == NULL) {
-        return NGX_ERROR;
-    }
+    } else {
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                       "http3 ref insert static[%ui] \"%V\"", index, value);
 
-    dt = ngx_http_v3_get_dynamic_table(c);
-    if (dt == NULL) {
-        return NGX_ERROR;
+        if (ngx_http_v3_lookup_static(c, index, &name, NULL) != NGX_OK) {
+            return NGX_ERROR;
+        }
     }
 
-    h = ngx_array_push(dt);
-    if (h == NULL) {
+    return ngx_http_v3_insert(c, &name, value);
+}
+
+
+ngx_int_t
+ngx_http_v3_insert(ngx_connection_t *c, ngx_str_t *name, ngx_str_t *value)
+{
+    u_char                       *p;
+    size_t                        size;
+    ngx_http_v3_header_t         *h;
+    ngx_http_v3_connection_t     *h3c;
+    ngx_http_v3_dynamic_table_t  *dt;
+
+    size = ngx_http_v3_table_entry_size(name, value);
+
+    if (ngx_http_v3_evict(c, size) != NGX_OK) {
         return NGX_ERROR;
     }
 
-    h->name = ref->name;
+    h3c = c->qs->parent->data;
+    dt = &h3c->table;
 
-    h->value.data = ngx_pstrdup(pc->pool, value);
-    if (h->value.data == NULL) {
-        h->value.len = 0;
+    ngx_log_debug4(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "http3 insert [%ui] \"%V\":\"%V\", size:%uz",
+                   dt->base + dt->nelts, name, value, size);
+
+    p = ngx_alloc(sizeof(ngx_http_v3_header_t) + name->len + value->len,
+                  c->log);
+    if (p == NULL) {
         return NGX_ERROR;
     }
 
+    h = (ngx_http_v3_header_t *) p;
+
+    h->name.data = p + sizeof(ngx_http_v3_header_t);
+    h->name.len = name->len;
+    h->value.data = ngx_cpymem(h->name.data, name->data, name->len);
     h->value.len = value->len;
+    ngx_memcpy(h->value.data, value->data, value->len);
+
+    dt->elts[dt->nelts++] = h;
+    dt->size += size;
+
+    /* TODO increment can be sent less often */
+
+    if (ngx_http_v3_client_inc_insert_count(c, 1) != NGX_OK) {
+        return NGX_ERROR;
+    }
 
     if (ngx_http_v3_new_header(c) != NGX_OK) {
         return NGX_ERROR;
@@ -192,95 +237,150 @@ ngx_http_v3_ref_insert(ngx_connection_t *c, ngx_uint_t dynamic,
 
 
 ngx_int_t
-ngx_http_v3_insert(ngx_connection_t *c, ngx_str_t *name,
-    ngx_str_t *value)
+ngx_http_v3_set_capacity(ngx_connection_t *c, ngx_uint_t capacity)
 {
-    ngx_array_t           *dt;
-    ngx_connection_t      *pc;
-    ngx_http_v3_header_t  *h;
+    ngx_uint_t                     max, prev_max;
+    ngx_connection_t              *pc;
+    ngx_pool_cleanup_t            *cln;
+    ngx_http_v3_header_t         **elts;
+    ngx_http_v3_srv_conf_t        *v3cf;
+    ngx_http_v3_connection_t      *h3c;
+    ngx_http_v3_dynamic_table_t   *dt;
 
-    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
-                   "http3 insert \"%V\":\"%V\"", name, value);
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "http3 set capacity %ui", capacity);
 
     pc = c->qs->parent;
+    h3c = pc->data;
+    v3cf = ngx_http_get_module_srv_conf(h3c->hc.conf_ctx, ngx_http_v3_module);
 
-    dt = ngx_http_v3_get_dynamic_table(c);
-    if (dt == NULL) {
+    if (capacity > v3cf->max_table_capacity) {
+        ngx_log_error(NGX_LOG_INFO, c->log, 0,
+                      "client exceeded http3_max_table_capacity limit");
         return NGX_ERROR;
     }
 
-    h = ngx_array_push(dt);
-    if (h == NULL) {
-        return NGX_ERROR;
-    }
+    dt = &h3c->table;
 
-    h->name.data = ngx_pstrdup(pc->pool, name);
-    if (h->name.data == NULL) {
-        h->name.len = 0;
-        h->value.len = 0;
-        return NGX_ERROR;
+    if (dt->size > capacity) {
+        if (ngx_http_v3_evict(c, dt->size - capacity) != NGX_OK) {
+            return NGX_ERROR;
+        }
     }
 
-    h->name.len = name->len;
+    max = capacity / 32;
+    prev_max = dt->capacity / 32;
 
-    h->value.data = ngx_pstrdup(pc->pool, value);
-    if (h->value.data == NULL) {
-        h->value.len = 0;
-        return NGX_ERROR;
-    }
+    if (max > prev_max) {
+        elts = ngx_alloc(max * sizeof(void *), c->log);
+        if (elts == NULL) {
+            return NGX_ERROR;
+        }
 
-    h->value.len = value->len;
+        if (dt->elts == NULL) {
+            cln = ngx_pool_cleanup_add(pc->pool, 0);
+            if (cln == NULL) {
+                return NGX_ERROR;
+            }
 
-    if (ngx_http_v3_new_header(c) != NGX_OK) {
-        return NGX_ERROR;
+            cln->handler = ngx_http_v3_cleanup_table;
+            cln->data = dt;
+
+        } else {
+            ngx_memcpy(elts, dt->elts, dt->nelts * sizeof(void *));
+            ngx_free(dt->elts);
+        }
+
+        dt->elts = elts;
     }
 
+    dt->capacity = capacity;
+
     return NGX_OK;
 }
 
 
-ngx_int_t
-ngx_http_v3_set_capacity(ngx_connection_t *c, ngx_uint_t capacity)
+static void
+ngx_http_v3_cleanup_table(void *data)
 {
-    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
-                   "http3 set capacity %ui", capacity);
+    ngx_http_v3_dynamic_table_t  *dt = data;
 
-    /* XXX ignore capacity */
+    ngx_uint_t  n;
 
-    return NGX_OK;
+    for (n = 0; n < dt->nelts; n++) {
+        ngx_free(dt->elts[n]);
+    }
+
+    ngx_free(dt->elts);
 }
 
 
-ngx_int_t
-ngx_http_v3_duplicate(ngx_connection_t *c, ngx_uint_t index)
+static ngx_int_t
+ngx_http_v3_evict(ngx_connection_t *c, size_t need)
 {
-    ngx_array_t           *dt;
-    ngx_http_v3_header_t  *ref, *h;
+    size_t                        size, target;
+    ngx_uint_t                    n;
+    ngx_http_v3_header_t         *h;
+    ngx_http_v3_connection_t     *h3c;
+    ngx_http_v3_dynamic_table_t  *dt;
 
-    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http3 duplicate %ui", index);
+    h3c = c->qs->parent->data;
+    dt = &h3c->table;
 
-    ref = ngx_http_v3_lookup_table(c, 1, index);
-    if (ref == NULL) {
+    if (need > dt->capacity) {
+        ngx_log_error(NGX_LOG_ERR, c->log, 0,
+                      "not enough dynamic table capacity");
         return NGX_ERROR;
     }
 
-    dt = ngx_http_v3_get_dynamic_table(c);
-    if (dt == NULL) {
-        return NGX_ERROR;
+    target = dt->capacity - need;
+    n = 0;
+
+    while (dt->size > target) {
+        h = dt->elts[n++];
+        size = ngx_http_v3_table_entry_size(&h->name, &h->value);
+
+        ngx_log_debug4(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                       "http3 evict [%ui] \"%V\":\"%V\" size:%uz",
+                       dt->base, &h->name, &h->value, size);
+
+        ngx_free(h);
+        dt->size -= size;
+    }
+
+    if (n) {
+        dt->nelts -= n;
+        dt->base += n;
+        ngx_memmove(dt->elts, &dt->elts[n], dt->nelts * sizeof(void *));
     }
 
-    h = ngx_array_push(dt);
-    if (h == NULL) {
+    return NGX_OK;
+}
+
+
+ngx_int_t
+ngx_http_v3_duplicate(ngx_connection_t *c, ngx_uint_t index)
+{
+    ngx_str_t                     name, value;
+    ngx_http_v3_connection_t     *h3c;
+    ngx_http_v3_dynamic_table_t  *dt;
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "http3 duplicate %ui", index);
+
+    h3c = c->qs->parent->data;
+    dt = &h3c->table;
+
+    if (dt->base + dt->nelts <= index) {
         return NGX_ERROR;
     }
 
-    *h = *ref;
+    index = dt->base + dt->nelts - 1 - index;
 
-    if (ngx_http_v3_new_header(c) != NGX_OK) {
+    if (ngx_http_v3_lookup(c, index, &name, &value) != NGX_OK) {
         return NGX_ERROR;
     }
 
-    return NGX_OK;
+    return ngx_http_v3_insert(c, &name, &value);
 }
 
 
@@ -320,94 +420,237 @@ ngx_http_v3_inc_insert_count(ngx_connection_t *c, ngx_uint_t inc)
 }
 
 
-static ngx_array_t *
-ngx_http_v3_get_dynamic_table(ngx_connection_t *c)
+ngx_int_t
+ngx_http_v3_lookup_static(ngx_connection_t *c, ngx_uint_t index,
+    ngx_str_t *name, ngx_str_t *value)
 {
-    ngx_connection_t          *pc;
-    ngx_http_v3_connection_t  *h3c;
+    ngx_uint_t             nelts;
+    ngx_http_v3_header_t  *h;
 
-    pc = c->qs->parent;
-    h3c = pc->data;
+    nelts = sizeof(ngx_http_v3_static_table)
+            / sizeof(ngx_http_v3_static_table[0]);
 
-    if (h3c->dynamic) {
-        return h3c->dynamic;
+    if (index >= nelts) {
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                       "http3 static[%ui] lookup out of bounds: %ui",
+                       index, nelts);
+        return NGX_ERROR;
     }
 
-    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http3 create dynamic table");
+    h = &ngx_http_v3_static_table[index];
+
+    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "http3 static[%ui] lookup \"%V\":\"%V\"",
+                   index, &h->name, &h->value);
+
+    if (name) {
+        *name = h->name;
+    }
 
-    h3c->dynamic = ngx_array_create(pc->pool, 1, sizeof(ngx_http_v3_header_t));
+    if (value) {
+        *value = h->value;
+    }
 
-    return h3c->dynamic;
+    return NGX_OK;
 }
 
 
-ngx_http_v3_header_t *
-ngx_http_v3_lookup_table(ngx_connection_t *c, ngx_uint_t dynamic,
-    ngx_uint_t index)
+ngx_int_t
+ngx_http_v3_lookup(ngx_connection_t *c, ngx_uint_t index, ngx_str_t *name,
+    ngx_str_t *value)
 {
-    ngx_uint_t             nelts;
-    ngx_array_t           *dt;
-    ngx_http_v3_header_t  *table;
+    ngx_http_v3_header_t         *h;
+    ngx_http_v3_connection_t     *h3c;
+    ngx_http_v3_dynamic_table_t  *dt;
 
-    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0, "http3 lookup %s[%ui]",
-                   dynamic ? "dynamic" : "static", index);
+    h3c = c->qs->parent->data;
+    dt = &h3c->table;
 
-    if (dynamic) {
-        dt = ngx_http_v3_get_dynamic_table(c);
-        if (dt == NULL) {
-            return NULL;
-        }
+    if (index < dt->base || index - dt->base >= dt->nelts) {
+        ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                       "http3 dynamic[%ui] lookup out of bounds: [%ui,%ui]",
+                       index, dt->base, dt->base + dt->nelts);
+        return NGX_ERROR;
+    }
 
-        table = dt->elts;
-        nelts = dt->nelts;
+    h = dt->elts[index - dt->base];
 
-    } else {
-        table = ngx_http_v3_static_table;
-        nelts = sizeof(ngx_http_v3_static_table)
-                / sizeof(ngx_http_v3_static_table[0]);
+    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "http3 dynamic[%ui] lookup \"%V\":\"%V\"",
+                   index, &h->name, &h->value);
+
+    if (name) {
+        *name = h->name;
     }
 
-    if (index >= nelts) {
-        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
-                       "http3 lookup out of bounds: %ui", nelts);
-        return NULL;
+    if (value) {
+        *value = h->value;
+    }
+
+    return NGX_OK;
+}
+
+
+ngx_int_t
+ngx_http_v3_decode_insert_count(ngx_connection_t *c, ngx_uint_t *insert_count)
+{
+    ngx_uint_t                    max_entries, full_range, max_value,
+                                  max_wrapped, req_insert_count;
+    ngx_http_v3_srv_conf_t       *v3cf;
+    ngx_http_v3_connection_t     *h3c;
+    ngx_http_v3_dynamic_table_t  *dt;
+
+    /* QPACK 4.5.1.1. Required Insert Count */
+
+    if (*insert_count == 0) {
+        return NGX_OK;
     }
 
-    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0, "http3 lookup \"%V\":\"%V\"",
-                   &table[index].name, &table[index].value);
+    h3c = c->qs->parent->data;
+    dt = &h3c->table;
+
+    v3cf = ngx_http_get_module_srv_conf(h3c->hc.conf_ctx, ngx_http_v3_module);
+
+    max_entries = v3cf->max_table_capacity / 32;
+    full_range = 2 * max_entries;
+
+    if (*insert_count > full_range) {
+        return NGX_ERROR;
+    }
+
+    max_value = dt->base + dt->nelts + max_entries;
+    max_wrapped = (max_value / full_range) * full_range;
+    req_insert_count = max_wrapped + *insert_count - 1;
+
+    if (req_insert_count > max_value) {
+        if (req_insert_count <= full_range) {
+            return NGX_ERROR;
+        }
+
+        req_insert_count -= full_range;
+    }
 
-    return &table[index];
+    if (req_insert_count == 0) {
+        return NGX_ERROR;
+    }
+
+    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "http3 decode insert_count %ui -> %ui",
+                   *insert_count, req_insert_count);
+
+    *insert_count = req_insert_count;
+
+    return NGX_OK;
 }
 
 
 ngx_int_t
 ngx_http_v3_check_insert_count(ngx_connection_t *c, ngx_uint_t insert_count)
 {
-    size_t                     n;
-    ngx_http_v3_connection_t  *h3c;
+    size_t                        n;
+    ngx_connection_t             *pc;
+    ngx_pool_cleanup_t           *cln;
+    ngx_http_v3_block_t          *block;
+    ngx_http_v3_srv_conf_t       *v3cf;
+    ngx_http_v3_connection_t     *h3c;
+    ngx_http_v3_dynamic_table_t  *dt;
 
-    h3c = c->qs->parent->data;
-    n = h3c->dynamic ? h3c->dynamic->nelts : 0;
+    pc = c->qs->parent;
+    h3c = pc->data;
+    dt = &h3c->table;
+
+    n = dt->base + dt->nelts;
 
     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
-                   "http3 check insert count %ui/%ui", insert_count, n);
+                   "http3 check insert count req:%ui, have:%ui",
+                   insert_count, n);
 
-    if (n < insert_count) {
-        /* XXX how to get notified? */
-        /* XXX wake all streams on any arrival to the encoder stream? */
-        return NGX_AGAIN;
+    if (n >= insert_count) {
+        return NGX_OK;
     }
 
-    return NGX_OK;
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http3 block stream");
+
+    block = NULL;
+
+    for (cln = c->pool->cleanup; cln; cln = cln->next) {
+        if (cln->handler == ngx_http_v3_unblock) {
+            block = cln->data;
+            break;
+        }
+    }
+
+    if (block == NULL) {
+        cln = ngx_pool_cleanup_add(c->pool, sizeof(ngx_http_v3_block_t));
+        if (cln == NULL) {
+            return NGX_ERROR;
+        }
+
+        cln->handler = ngx_http_v3_unblock;
+
+        block = cln->data;
+        block->queue.prev = NULL;
+        block->connection = c;
+        block->nblocked = &h3c->nblocked;
+    }
+
+    if (block->queue.prev == NULL) {
+        v3cf = ngx_http_get_module_srv_conf(h3c->hc.conf_ctx,
+                                            ngx_http_v3_module);
+
+        if (h3c->nblocked == v3cf->max_blocked_streams) {
+            ngx_log_error(NGX_LOG_INFO, c->log, 0,
+                          "client exceeded http3_max_blocked_streams limit");
+            return NGX_ERROR;
+        }
+
+        h3c->nblocked++;
+        ngx_queue_insert_tail(&h3c->blocked, &block->queue);
+    }
+
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "http3 blocked:%ui", h3c->nblocked);
+
+    return NGX_BUSY;
+}
+
+
+static void
+ngx_http_v3_unblock(void *data)
+{
+    ngx_http_v3_block_t  *block = data;
+
+    if (block->queue.prev) {
+        ngx_queue_remove(&block->queue);
+        block->queue.prev = NULL;
+        (*block->nblocked)--;
+    }
 }
 
 
 static ngx_int_t
 ngx_http_v3_new_header(ngx_connection_t *c)
 {
-    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http3 new dynamic header");
+    ngx_queue_t               *q;
+    ngx_connection_t          *bc;
+    ngx_http_v3_block_t       *block;
+    ngx_http_v3_connection_t  *h3c;
+
+    h3c = c->qs->parent->data;
 
-    /* XXX report all waiting streams of a new header */
+    ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
+                   "http3 new dynamic header, blocked:%ui", h3c->nblocked);
+
+    while (!ngx_queue_empty(&h3c->blocked)) {
+        q = ngx_queue_head(&h3c->blocked);
+        block = (ngx_http_v3_block_t *) q;
+        bc = block->connection;
+
+        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, bc->log, 0, "http3 unblock stream");
+
+        ngx_http_v3_unblock(block);
+        ngx_post_event(bc->read, &ngx_posted_events);
+    }
 
     return NGX_OK;
 }