Adding upstream version 2.4.57.upstream/2.4.57

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 864 insertions, 0 deletions

diff --git a/modules/http2/h2_c2.c b/modules/http2/h2_c2.c
new file mode 100644
index 0000000..44a08d0
--- /dev/null
+++ b/modules/http2/h2_c2.c
@@ -0,0 +1,864 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+ 
+#include <assert.h>
+#include <stddef.h>
+
+#include <apr_atomic.h>
+#include <apr_strings.h>
+
+#include <httpd.h>
+#include <http_core.h>
+#include <http_config.h>
+#include <http_connection.h>
+#include <http_protocol.h>
+#include <http_request.h>
+#include <http_log.h>
+#include <http_vhost.h>
+#include <util_filter.h>
+#include <ap_mmn.h>
+#include <ap_mpm.h>
+#include <mpm_common.h>
+#include <mod_core.h>
+#include <scoreboard.h>
+
+#include "h2_private.h"
+#include "h2.h"
+#include "h2_bucket_beam.h"
+#include "h2_c1.h"
+#include "h2_config.h"
+#include "h2_conn_ctx.h"
+#include "h2_c2_filter.h"
+#include "h2_protocol.h"
+#include "h2_mplx.h"
+#include "h2_request.h"
+#include "h2_headers.h"
+#include "h2_session.h"
+#include "h2_stream.h"
+#include "h2_c2.h"
+#include "h2_util.h"
+
+
+static module *mpm_module;
+static int mpm_supported = 1;
+static apr_socket_t *dummy_socket;
+
+#if AP_HAS_RESPONSE_BUCKETS
+
+static ap_filter_rec_t *c2_net_in_filter_handle;
+static ap_filter_rec_t *c2_net_out_filter_handle;
+static ap_filter_rec_t *c2_request_in_filter_handle;
+static ap_filter_rec_t *c2_notes_out_filter_handle;
+
+#endif /* AP_HAS_RESPONSE_BUCKETS */
+
+static void check_modules(int force)
+{
+    static int checked = 0;
+    int i;
+
+    if (force || !checked) {
+        for (i = 0; ap_loaded_modules[i]; ++i) {
+            module *m = ap_loaded_modules[i];
+
+            if (!strcmp("event.c", m->name)) {
+                mpm_module = m;
+                break;
+            }
+            else if (!strcmp("motorz.c", m->name)) {
+                mpm_module = m;
+                break;
+            }
+            else if (!strcmp("mpm_netware.c", m->name)) {
+                mpm_module = m;
+                break;
+            }
+            else if (!strcmp("prefork.c", m->name)) {
+                mpm_module = m;
+                /* While http2 can work really well on prefork, it collides
+                 * today's use case for prefork: running single-thread app engines
+                 * like php. If we restrict h2_workers to 1 per process, php will
+                 * work fine, but browser will be limited to 1 active request at a
+                 * time. */
+                mpm_supported = 0;
+                break;
+            }
+            else if (!strcmp("simple_api.c", m->name)) {
+                mpm_module = m;
+                mpm_supported = 0;
+                break;
+            }
+            else if (!strcmp("mpm_winnt.c", m->name)) {
+                mpm_module = m;
+                break;
+            }
+            else if (!strcmp("worker.c", m->name)) {
+                mpm_module = m;
+                break;
+            }
+        }
+        checked = 1;
+    }
+}
+
+const char *h2_conn_mpm_name(void)
+{
+    check_modules(0);
+    return mpm_module? mpm_module->name : "unknown";
+}
+
+int h2_mpm_supported(void)
+{
+    check_modules(0);
+    return mpm_supported;
+}
+
+apr_status_t h2_c2_child_init(apr_pool_t *pool, server_rec *s)
+{
+    check_modules(1);
+    return apr_socket_create(&dummy_socket, APR_INET, SOCK_STREAM,
+                             APR_PROTO_TCP, pool);
+}
+
+void h2_c2_destroy(conn_rec *c2)
+{
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE3, 0, c2,
+                  "h2_c2(%s): destroy", c2->log_id);
+    apr_pool_destroy(c2->pool);
+}
+
+void h2_c2_abort(conn_rec *c2, conn_rec *from)
+{
+    h2_conn_ctx_t *conn_ctx = h2_conn_ctx_get(c2);
+
+    AP_DEBUG_ASSERT(conn_ctx);
+    AP_DEBUG_ASSERT(conn_ctx->stream_id);
+    if (conn_ctx->beam_in) {
+        h2_beam_abort(conn_ctx->beam_in, from);
+    }
+    if (conn_ctx->beam_out) {
+        h2_beam_abort(conn_ctx->beam_out, from);
+    }
+    c2->aborted = 1;
+}
+
+typedef struct {
+    apr_bucket_brigade *bb;       /* c2: data in holding area */
+} h2_c2_fctx_in_t;
+
+static apr_status_t h2_c2_filter_in(ap_filter_t* f,
+                                           apr_bucket_brigade* bb,
+                                           ap_input_mode_t mode,
+                                           apr_read_type_e block,
+                                           apr_off_t readbytes)
+{
+    h2_conn_ctx_t *conn_ctx;
+    h2_c2_fctx_in_t *fctx = f->ctx;
+    apr_status_t status = APR_SUCCESS;
+    apr_bucket *b;
+    apr_off_t bblen;
+    apr_size_t rmax = (readbytes < APR_INT32_MAX)?
+                       (apr_size_t)readbytes : APR_INT32_MAX;
+    
+    conn_ctx = h2_conn_ctx_get(f->c);
+    AP_DEBUG_ASSERT(conn_ctx);
+
+    if (mode == AP_MODE_INIT) {
+        return ap_get_brigade(f->c->input_filters, bb, mode, block, readbytes);
+    }
+    
+    if (f->c->aborted) {
+        return APR_ECONNABORTED;
+    }
+    
+    if (APLOGctrace3(f->c)) {
+        ap_log_cerror(APLOG_MARK, APLOG_TRACE3, 0, f->c,
+                      "h2_c2_in(%s-%d): read, mode=%d, block=%d, readbytes=%ld",
+                      conn_ctx->id, conn_ctx->stream_id, mode, block,
+                      (long)readbytes);
+    }
+
+    if (!fctx) {
+        fctx = apr_pcalloc(f->c->pool, sizeof(*fctx));
+        f->ctx = fctx;
+        fctx->bb = apr_brigade_create(f->c->pool, f->c->bucket_alloc);
+        if (!conn_ctx->beam_in) {
+            b = apr_bucket_eos_create(f->c->bucket_alloc);
+            APR_BRIGADE_INSERT_TAIL(fctx->bb, b);
+        }
+    }
+    
+    while (APR_BRIGADE_EMPTY(fctx->bb)) {
+        /* Get more input data for our request. */
+        if (APLOGctrace2(f->c)) {
+            ap_log_cerror(APLOG_MARK, APLOG_TRACE2, status, f->c,
+                          "h2_c2_in(%s-%d): get more data from mplx, block=%d, "
+                          "readbytes=%ld",
+                          conn_ctx->id, conn_ctx->stream_id, block, (long)readbytes);
+        }
+        if (conn_ctx->beam_in) {
+            if (conn_ctx->pipe_in[H2_PIPE_OUT]) {
+receive:
+                status = h2_beam_receive(conn_ctx->beam_in, f->c, fctx->bb, APR_NONBLOCK_READ,
+                                         conn_ctx->mplx->stream_max_mem);
+                if (APR_STATUS_IS_EAGAIN(status) && APR_BLOCK_READ == block) {
+                    status = h2_util_wait_on_pipe(conn_ctx->pipe_in[H2_PIPE_OUT]);
+                    if (APR_SUCCESS == status) {
+                        goto receive;
+                    }
+                }
+            }
+            else {
+                status = h2_beam_receive(conn_ctx->beam_in, f->c, fctx->bb, block,
+                                         conn_ctx->mplx->stream_max_mem);
+            }
+        }
+        else {
+            status = APR_EOF;
+        }
+        
+        if (APLOGctrace3(f->c)) {
+            ap_log_cerror(APLOG_MARK, APLOG_TRACE3, status, f->c,
+                          "h2_c2_in(%s-%d): read returned",
+                          conn_ctx->id, conn_ctx->stream_id);
+        }
+        if (APR_STATUS_IS_EAGAIN(status) 
+            && (mode == AP_MODE_GETLINE || block == APR_BLOCK_READ)) {
+            /* chunked input handling does not seem to like it if we
+             * return with APR_EAGAIN from a GETLINE read... 
+             * upload 100k test on test-ser.example.org hangs */
+            status = APR_SUCCESS;
+        }
+        else if (APR_STATUS_IS_EOF(status)) {
+            break;
+        }
+        else if (status != APR_SUCCESS) {
+            conn_ctx->last_err = status;
+            return status;
+        }
+
+        if (APLOGctrace3(f->c)) {
+            h2_util_bb_log(f->c, conn_ctx->stream_id, APLOG_TRACE3,
+                        "c2 input recv raw", fctx->bb);
+        }
+        if (h2_c_logio_add_bytes_in) {
+            apr_brigade_length(bb, 0, &bblen);
+            h2_c_logio_add_bytes_in(f->c, bblen);
+        }
+    }
+    
+    /* Nothing there, no more data to get. Return. */
+    if (status == APR_EOF && APR_BRIGADE_EMPTY(fctx->bb)) {
+        return status;
+    }
+
+    if (APLOGctrace3(f->c)) {
+        h2_util_bb_log(f->c, conn_ctx->stream_id, APLOG_TRACE3,
+                    "c2 input.bb", fctx->bb);
+    }
+           
+    if (APR_BRIGADE_EMPTY(fctx->bb)) {
+        if (APLOGctrace3(f->c)) {
+            ap_log_cerror(APLOG_MARK, APLOG_TRACE3, 0, f->c,
+                          "h2_c2_in(%s-%d): no data",
+                          conn_ctx->id, conn_ctx->stream_id);
+        }
+        return (block == APR_NONBLOCK_READ)? APR_EAGAIN : APR_EOF;
+    }
+    
+    if (mode == AP_MODE_EXHAUSTIVE) {
+        /* return all we have */
+        APR_BRIGADE_CONCAT(bb, fctx->bb);
+    }
+    else if (mode == AP_MODE_READBYTES) {
+        status = h2_brigade_concat_length(bb, fctx->bb, rmax);
+    }
+    else if (mode == AP_MODE_SPECULATIVE) {
+        status = h2_brigade_copy_length(bb, fctx->bb, rmax);
+    }
+    else if (mode == AP_MODE_GETLINE) {
+        /* we are reading a single LF line, e.g. the HTTP headers. 
+         * this has the nasty side effect to split the bucket, even
+         * though it ends with CRLF and creates a 0 length bucket */
+        status = apr_brigade_split_line(bb, fctx->bb, block,
+                                        HUGE_STRING_LEN);
+        if (APLOGctrace3(f->c)) {
+            char buffer[1024];
+            apr_size_t len = sizeof(buffer)-1;
+            apr_brigade_flatten(bb, buffer, &len);
+            buffer[len] = 0;
+            ap_log_cerror(APLOG_MARK, APLOG_TRACE3, status, f->c,
+                          "h2_c2_in(%s-%d): getline: %s",
+                          conn_ctx->id, conn_ctx->stream_id, buffer);
+        }
+    }
+    else {
+        /* Hmm, well. There is mode AP_MODE_EATCRLF, but we chose not
+         * to support it. Seems to work. */
+        ap_log_cerror(APLOG_MARK, APLOG_ERR, APR_ENOTIMPL, f->c,
+                      APLOGNO(03472) 
+                      "h2_c2_in(%s-%d), unsupported READ mode %d",
+                      conn_ctx->id, conn_ctx->stream_id, mode);
+        status = APR_ENOTIMPL;
+    }
+    
+    if (APLOGctrace3(f->c)) {
+        apr_brigade_length(bb, 0, &bblen);
+        ap_log_cerror(APLOG_MARK, APLOG_TRACE3, status, f->c,
+                      "h2_c2_in(%s-%d): %ld data bytes",
+                      conn_ctx->id, conn_ctx->stream_id, (long)bblen);
+    }
+    return status;
+}
+
+static apr_status_t beam_out(conn_rec *c2, h2_conn_ctx_t *conn_ctx, apr_bucket_brigade* bb)
+{
+    apr_off_t written, header_len = 0;
+    apr_status_t rv;
+
+    if (h2_c_logio_add_bytes_out) {
+        /* mod_logio wants to report the number of bytes  written in a
+         * response, including header and footer fields. Since h2 converts
+         * those during c1 processing into the HPACKed h2 HEADER frames,
+         * we need to give mod_logio something here and count just the
+         * raw lengths of all headers in the buckets. */
+        apr_bucket *b;
+        for (b = APR_BRIGADE_FIRST(bb);
+             b != APR_BRIGADE_SENTINEL(bb);
+             b = APR_BUCKET_NEXT(b)) {
+#if AP_HAS_RESPONSE_BUCKETS
+            if (AP_BUCKET_IS_RESPONSE(b)) {
+                header_len += (apr_off_t)response_length_estimate(b->data);
+            }
+            if (AP_BUCKET_IS_HEADERS(b)) {
+                header_len += (apr_off_t)headers_length_estimate(b->data);
+            }
+#else
+            if (H2_BUCKET_IS_HEADERS(b)) {
+                header_len += (apr_off_t)h2_bucket_headers_headers_length(b);
+            }
+#endif /* AP_HAS_RESPONSE_BUCKETS */
+        }
+    }
+
+    rv = h2_beam_send(conn_ctx->beam_out, c2, bb, APR_BLOCK_READ, &written);
+
+    if (APR_STATUS_IS_EAGAIN(rv)) {
+        rv = APR_SUCCESS;
+    }
+    if (written && h2_c_logio_add_bytes_out) {
+        h2_c_logio_add_bytes_out(c2, written + header_len);
+    }
+    return rv;
+}
+
+static apr_status_t h2_c2_filter_out(ap_filter_t* f, apr_bucket_brigade* bb)
+{
+    h2_conn_ctx_t *conn_ctx = h2_conn_ctx_get(f->c);
+    apr_status_t rv;
+
+    ap_assert(conn_ctx);
+#if AP_HAS_RESPONSE_BUCKETS
+    if (!conn_ctx->has_final_response) {
+        apr_bucket *e;
+
+        for (e = APR_BRIGADE_FIRST(bb);
+             e != APR_BRIGADE_SENTINEL(bb);
+             e = APR_BUCKET_NEXT(e))
+        {
+            if (AP_BUCKET_IS_RESPONSE(e)) {
+                ap_bucket_response *resp = e->data;
+                if (resp->status >= 200) {
+                    conn_ctx->has_final_response = 1;
+                    break;
+                }
+            }
+            if (APR_BUCKET_IS_EOS(e)) {
+                break;
+            }
+        }
+    }
+#endif /* AP_HAS_RESPONSE_BUCKETS */
+    rv = beam_out(f->c, conn_ctx, bb);
+
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE2, rv, f->c,
+                  "h2_c2(%s-%d): output leave",
+                  conn_ctx->id, conn_ctx->stream_id);
+    if (APR_SUCCESS != rv) {
+        h2_c2_abort(f->c, f->c);
+    }
+    return rv;
+}
+
+static void check_push(request_rec *r, const char *tag)
+{
+    apr_array_header_t *push_list = h2_config_push_list(r);
+
+    if (!r->expecting_100 && push_list && push_list->nelts > 0) {
+        int i, old_status;
+        const char *old_line;
+
+        ap_log_rerror(APLOG_MARK, APLOG_TRACE1, 0, r,
+                      "%s, early announcing %d resources for push",
+                      tag, push_list->nelts);
+        for (i = 0; i < push_list->nelts; ++i) {
+            h2_push_res *push = &APR_ARRAY_IDX(push_list, i, h2_push_res);
+            apr_table_add(r->headers_out, "Link",
+                           apr_psprintf(r->pool, "<%s>; rel=preload%s",
+                                        push->uri_ref, push->critical? "; critical" : ""));
+        }
+        old_status = r->status;
+        old_line = r->status_line;
+        r->status = 103;
+        r->status_line = "103 Early Hints";
+        ap_send_interim_response(r, 1);
+        r->status = old_status;
+        r->status_line = old_line;
+    }
+}
+
+static int c2_hook_fixups(request_rec *r)
+{
+    conn_rec *c2 = r->connection;
+    h2_conn_ctx_t *conn_ctx;
+
+    if (!c2->master || !(conn_ctx = h2_conn_ctx_get(c2)) || !conn_ctx->stream_id) {
+        return DECLINED;
+    }
+
+    check_push(r, "late_fixup");
+
+    return DECLINED;
+}
+
+#if AP_HAS_RESPONSE_BUCKETS
+
+static void c2_pre_read_request(request_rec *r, conn_rec *c2)
+{
+    h2_conn_ctx_t *conn_ctx;
+
+    if (!c2->master || !(conn_ctx = h2_conn_ctx_get(c2)) || !conn_ctx->stream_id) {
+        return;
+    }
+    ap_log_rerror(APLOG_MARK, APLOG_TRACE3, 0, r,
+                  "h2_c2(%s-%d): adding request filters",
+                  conn_ctx->id, conn_ctx->stream_id);
+    ap_add_input_filter_handle(c2_request_in_filter_handle, NULL, r, r->connection);
+    ap_add_output_filter_handle(c2_notes_out_filter_handle, NULL, r, r->connection);
+}
+
+static int c2_post_read_request(request_rec *r)
+{
+    h2_conn_ctx_t *conn_ctx;
+    conn_rec *c2 = r->connection;
+    apr_time_t timeout;
+
+    if (!c2->master || !(conn_ctx = h2_conn_ctx_get(c2)) || !conn_ctx->stream_id) {
+        return DECLINED;
+    }
+    /* Now that the request_rec is fully initialized, set relevant params */
+    conn_ctx->server = r->server;
+    timeout = h2_config_geti64(r, r->server, H2_CONF_STREAM_TIMEOUT);
+    if (timeout <= 0) {
+        timeout = r->server->timeout;
+    }
+    h2_conn_ctx_set_timeout(conn_ctx, timeout);
+    /* We only handle this one request on the connection and tell everyone
+     * that there is no need to keep it "clean" if something fails. Also,
+     * this prevents mod_reqtimeout from doing funny business with monitoring
+     * keepalive timeouts.
+     */
+    r->connection->keepalive = AP_CONN_CLOSE;
+
+    if (conn_ctx->beam_in && !apr_table_get(r->headers_in, "Content-Length")) {
+        r->body_indeterminate = 1;
+    }
+
+    if (h2_config_sgeti(conn_ctx->server, H2_CONF_COPY_FILES)) {
+        ap_log_rerror(APLOG_MARK, APLOG_TRACE1, 0, r,
+                      "h2_mplx(%s-%d): copy_files in output",
+                      conn_ctx->id, conn_ctx->stream_id);
+        h2_beam_set_copy_files(conn_ctx->beam_out, 1);
+    }
+
+    /* Add the raw bytes of the request (e.g. header frame lengths to
+     * the logio for this request. */
+    if (conn_ctx->request->raw_bytes && h2_c_logio_add_bytes_in) {
+        h2_c_logio_add_bytes_in(c2, conn_ctx->request->raw_bytes);
+    }
+    return OK;
+}
+
+static int c2_hook_pre_connection(conn_rec *c2, void *csd)
+{
+    h2_conn_ctx_t *conn_ctx;
+
+    if (!c2->master || !(conn_ctx = h2_conn_ctx_get(c2)) || !conn_ctx->stream_id) {
+        return DECLINED;
+    }
+
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, c2,
+                  "h2_c2(%s-%d), adding filters",
+                  conn_ctx->id, conn_ctx->stream_id);
+    ap_add_input_filter_handle(c2_net_in_filter_handle, NULL, NULL, c2);
+    ap_add_output_filter_handle(c2_net_out_filter_handle, NULL, NULL, c2);
+    if (c2->keepalives == 0) {
+        /* Simulate that we had already a request on this connection. Some
+         * hooks trigger special behaviour when keepalives is 0.
+         * (Not necessarily in pre_connection, but later. Set it here, so it
+         * is in place.) */
+        c2->keepalives = 1;
+        /* We signal that this connection will be closed after the request.
+         * Which is true in that sense that we throw away all traffic data
+         * on this c2 connection after each requests. Although we might
+         * reuse internal structures like memory pools.
+         * The wanted effect of this is that httpd does not try to clean up
+         * any dangling data on this connection when a request is done. Which
+         * is unnecessary on a h2 stream.
+         */
+        c2->keepalive = AP_CONN_CLOSE;
+    }
+    return OK;
+}
+
+void h2_c2_register_hooks(void)
+{
+    /* When the connection processing actually starts, we might
+     * take over, if the connection is for a h2 stream.
+     */
+    ap_hook_pre_connection(c2_hook_pre_connection,
+                           NULL, NULL, APR_HOOK_MIDDLE);
+
+    /* We need to manipulate the standard HTTP/1.1 protocol filters and
+     * install our own. This needs to be done very early. */
+    ap_hook_pre_read_request(c2_pre_read_request, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_post_read_request(c2_post_read_request, NULL, NULL, APR_HOOK_REALLY_FIRST);
+    ap_hook_fixups(c2_hook_fixups, NULL, NULL, APR_HOOK_LAST);
+
+    c2_net_in_filter_handle =
+        ap_register_input_filter("H2_C2_NET_IN", h2_c2_filter_in,
+                                 NULL, AP_FTYPE_NETWORK);
+    c2_net_out_filter_handle =
+        ap_register_output_filter("H2_C2_NET_OUT", h2_c2_filter_out,
+                                  NULL, AP_FTYPE_NETWORK);
+    c2_request_in_filter_handle =
+        ap_register_input_filter("H2_C2_REQUEST_IN", h2_c2_filter_request_in,
+                                 NULL, AP_FTYPE_PROTOCOL);
+    c2_notes_out_filter_handle =
+        ap_register_output_filter("H2_C2_NOTES_OUT", h2_c2_filter_notes_out,
+                                  NULL, AP_FTYPE_PROTOCOL);
+}
+
+#else /* AP_HAS_RESPONSE_BUCKETS */
+
+static apr_status_t c2_run_pre_connection(conn_rec *c2, apr_socket_t *csd)
+{
+    if (c2->keepalives == 0) {
+        /* Simulate that we had already a request on this connection. Some
+         * hooks trigger special behaviour when keepalives is 0.
+         * (Not necessarily in pre_connection, but later. Set it here, so it
+         * is in place.) */
+        c2->keepalives = 1;
+        /* We signal that this connection will be closed after the request.
+         * Which is true in that sense that we throw away all traffic data
+         * on this c2 connection after each requests. Although we might
+         * reuse internal structures like memory pools.
+         * The wanted effect of this is that httpd does not try to clean up
+         * any dangling data on this connection when a request is done. Which
+         * is unnecessary on a h2 stream.
+         */
+        c2->keepalive = AP_CONN_CLOSE;
+        return ap_run_pre_connection(c2, csd);
+    }
+    ap_assert(c2->output_filters);
+    return APR_SUCCESS;
+}
+
+apr_status_t h2_c2_process(conn_rec *c2, apr_thread_t *thread, int worker_id)
+{
+    h2_conn_ctx_t *conn_ctx = h2_conn_ctx_get(c2);
+
+    ap_assert(conn_ctx);
+    ap_assert(conn_ctx->mplx);
+
+    /* See the discussion at <https://github.com/icing/mod_h2/issues/195>
+     *
+     * Each conn_rec->id is supposed to be unique at a point in time. Since
+     * some modules (and maybe external code) uses this id as an identifier
+     * for the request_rec they handle, it needs to be unique for secondary
+     * connections also.
+     *
+     * The MPM module assigns the connection ids and mod_unique_id is using
+     * that one to generate identifier for requests. While the implementation
+     * works for HTTP/1.x, the parallel execution of several requests per
+     * connection will generate duplicate identifiers on load.
+     *
+     * The original implementation for secondary connection identifiers used
+     * to shift the master connection id up and assign the stream id to the
+     * lower bits. This was cramped on 32 bit systems, but on 64bit there was
+     * enough space.
+     *
+     * As issue 195 showed, mod_unique_id only uses the lower 32 bit of the
+     * connection id, even on 64bit systems. Therefore collisions in request ids.
+     *
+     * The way master connection ids are generated, there is some space "at the
+     * top" of the lower 32 bits on allmost all systems. If you have a setup
+     * with 64k threads per child and 255 child processes, you live on the edge.
+     *
+     * The new implementation shifts 8 bits and XORs in the worker
+     * id. This will experience collisions with > 256 h2 workers and heavy
+     * load still. There seems to be no way to solve this in all possible
+     * configurations by mod_h2 alone.
+     */
+    c2->id = (c2->master->id << 8)^worker_id;
+
+    if (!conn_ctx->pre_conn_done) {
+        ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, c2,
+                      "h2_c2(%s-%d), adding filters",
+                      conn_ctx->id, conn_ctx->stream_id);
+        ap_add_input_filter("H2_C2_NET_IN", NULL, NULL, c2);
+        ap_add_output_filter("H2_C2_NET_CATCH_H1", NULL, NULL, c2);
+        ap_add_output_filter("H2_C2_NET_OUT", NULL, NULL, c2);
+
+        c2_run_pre_connection(c2, ap_get_conn_socket(c2));
+        conn_ctx->pre_conn_done = 1;
+    }
+
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c2,
+                  "h2_c2(%s-%d): process connection",
+                  conn_ctx->id, conn_ctx->stream_id);
+
+    c2->current_thread = thread;
+    ap_run_process_connection(c2);
+
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c2,
+                  "h2_c2(%s-%d): processing done",
+                  conn_ctx->id, conn_ctx->stream_id);
+
+    return APR_SUCCESS;
+}
+
+static apr_status_t c2_process(h2_conn_ctx_t *conn_ctx, conn_rec *c)
+{
+    const h2_request *req = conn_ctx->request;
+    conn_state_t *cs = c->cs;
+    request_rec *r;
+    const char *tenc;
+    apr_time_t timeout;
+
+    r = h2_create_request_rec(conn_ctx->request, c, conn_ctx->beam_in == NULL);
+    if (!r) {
+        ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c,
+                      "h2_c2(%s-%d): create request_rec failed, r=NULL",
+                      conn_ctx->id, conn_ctx->stream_id);
+        goto cleanup;
+    }
+    if (r->status != HTTP_OK) {
+        ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c,
+                      "h2_c2(%s-%d): create request_rec failed, r->status=%d",
+                      conn_ctx->id, conn_ctx->stream_id, r->status);
+        goto cleanup;
+    }
+
+    tenc = apr_table_get(r->headers_in, "Transfer-Encoding");
+    conn_ctx->input_chunked = tenc && ap_is_chunked(r->pool, tenc);
+
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c,
+                  "h2_c2(%s-%d): created request_rec for %s",
+                  conn_ctx->id, conn_ctx->stream_id, r->the_request);
+    conn_ctx->server = r->server;
+    timeout = h2_config_geti64(r, r->server, H2_CONF_STREAM_TIMEOUT);
+    if (timeout <= 0) {
+        timeout = r->server->timeout;
+    }
+    h2_conn_ctx_set_timeout(conn_ctx, timeout);
+
+    if (h2_config_sgeti(conn_ctx->server, H2_CONF_COPY_FILES)) {
+        ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c,
+                      "h2_mplx(%s-%d): copy_files in output",
+                      conn_ctx->id, conn_ctx->stream_id);
+        h2_beam_set_copy_files(conn_ctx->beam_out, 1);
+    }
+
+    ap_update_child_status(c->sbh, SERVER_BUSY_WRITE, r);
+    if (cs) {
+        cs->state = CONN_STATE_HANDLER;
+    }
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c,
+                  "h2_c2(%s-%d): start process_request",
+                  conn_ctx->id, conn_ctx->stream_id);
+
+    /* Add the raw bytes of the request (e.g. header frame lengths to
+     * the logio for this request. */
+    if (req->raw_bytes && h2_c_logio_add_bytes_in) {
+        h2_c_logio_add_bytes_in(c, req->raw_bytes);
+    }
+
+    ap_process_request(r);
+    /* After the call to ap_process_request, the
+     * request pool may have been deleted. */
+    r = NULL;
+    if (conn_ctx->beam_out) {
+        h2_beam_close(conn_ctx->beam_out, c);
+    }
+
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c,
+                  "h2_c2(%s-%d): process_request done",
+                  conn_ctx->id, conn_ctx->stream_id);
+    if (cs)
+        cs->state = CONN_STATE_WRITE_COMPLETION;
+
+cleanup:
+    return APR_SUCCESS;
+}
+
+conn_rec *h2_c2_create(conn_rec *c1, apr_pool_t *parent,
+                       apr_bucket_alloc_t *buckt_alloc)
+{
+    apr_pool_t *pool;
+    conn_rec *c2;
+    void *cfg;
+
+    ap_assert(c1);
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE3, 0, c1,
+                  "h2_c2: create for c1(%ld)", c1->id);
+
+    /* We create a pool with its own allocator to be used for
+     * processing a request. This is the only way to have the processing
+     * independent of its parent pool in the sense that it can work in
+     * another thread.
+     */
+    apr_pool_create(&pool, parent);
+    apr_pool_tag(pool, "h2_c2_conn");
+
+    c2 = (conn_rec *) apr_palloc(pool, sizeof(conn_rec));
+    memcpy(c2, c1, sizeof(conn_rec));
+
+    c2->master                 = c1;
+    c2->pool                   = pool;
+    c2->conn_config            = ap_create_conn_config(pool);
+    c2->notes                  = apr_table_make(pool, 5);
+    c2->input_filters          = NULL;
+    c2->output_filters         = NULL;
+    c2->keepalives             = 0;
+#if AP_MODULE_MAGIC_AT_LEAST(20180903, 1)
+    c2->filter_conn_ctx        = NULL;
+#endif
+    c2->bucket_alloc           = apr_bucket_alloc_create(pool);
+#if !AP_MODULE_MAGIC_AT_LEAST(20180720, 1)
+    c2->data_in_input_filters  = 0;
+    c2->data_in_output_filters = 0;
+#endif
+    /* prevent mpm_event from making wrong assumptions about this connection,
+     * like e.g. using its socket for an async read check. */
+    c2->clogging_input_filters = 1;
+    c2->log                    = NULL;
+    c2->aborted                = 0;
+    /* We cannot install the master connection socket on the secondary, as
+     * modules mess with timeouts/blocking of the socket, with
+     * unwanted side effects to the master connection processing.
+     * Fortunately, since we never use the secondary socket, we can just install
+     * a single, process-wide dummy and everyone is happy.
+     */
+    ap_set_module_config(c2->conn_config, &core_module, dummy_socket);
+    /* TODO: these should be unique to this thread */
+    c2->sbh = NULL; /*c1->sbh;*/
+    /* TODO: not all mpm modules have learned about secondary connections yet.
+     * copy their config from master to secondary.
+     */
+    if (mpm_module) {
+        cfg = ap_get_module_config(c1->conn_config, mpm_module);
+        ap_set_module_config(c2->conn_config, mpm_module, cfg);
+    }
+
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE3, 0, c2,
+                  "h2_c2(%s): created", c2->log_id);
+    return c2;
+}
+
+static int h2_c2_hook_post_read_request(request_rec *r)
+{
+    h2_conn_ctx_t *conn_ctx = h2_conn_ctx_get(r->connection);
+
+    if (conn_ctx && conn_ctx->stream_id) {
+
+        ap_log_rerror(APLOG_MARK, APLOG_TRACE3, 0, r,
+                      "h2_c2(%s-%d): adding request filters",
+                      conn_ctx->id, conn_ctx->stream_id);
+
+        /* setup the correct filters to process the request for h2 */
+        ap_add_input_filter("H2_C2_REQUEST_IN", NULL, r, r->connection);
+
+        /* replace the core http filter that formats response headers
+         * in HTTP/1 with our own that collects status and headers */
+        ap_remove_output_filter_byhandle(r->output_filters, "HTTP_HEADER");
+
+        ap_add_output_filter("H2_C2_RESPONSE_OUT", NULL, r, r->connection);
+        ap_add_output_filter("H2_C2_TRAILERS_OUT", NULL, r, r->connection);
+    }
+    return DECLINED;
+}
+
+static int h2_c2_hook_process(conn_rec* c)
+{
+    h2_conn_ctx_t *ctx;
+
+    if (!c->master) {
+        return DECLINED;
+    }
+
+    ctx = h2_conn_ctx_get(c);
+    if (ctx->stream_id) {
+        ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c,
+                      "h2_h2, processing request directly");
+        c2_process(ctx, c);
+        return DONE;
+    }
+    else {
+        ap_log_cerror(APLOG_MARK, APLOG_TRACE1, 0, c,
+                      "secondary_conn(%ld): no h2 stream assing?", c->id);
+    }
+    return DECLINED;
+}
+
+void h2_c2_register_hooks(void)
+{
+    /* When the connection processing actually starts, we might
+     * take over, if the connection is for a h2 stream.
+     */
+    ap_hook_process_connection(h2_c2_hook_process,
+                               NULL, NULL, APR_HOOK_FIRST);
+    /* We need to manipulate the standard HTTP/1.1 protocol filters and
+     * install our own. This needs to be done very early. */
+    ap_hook_post_read_request(h2_c2_hook_post_read_request, NULL, NULL, APR_HOOK_REALLY_FIRST);
+    ap_hook_fixups(c2_hook_fixups, NULL, NULL, APR_HOOK_LAST);
+
+    ap_register_input_filter("H2_C2_NET_IN", h2_c2_filter_in,
+                             NULL, AP_FTYPE_NETWORK);
+    ap_register_output_filter("H2_C2_NET_OUT", h2_c2_filter_out,
+                              NULL, AP_FTYPE_NETWORK);
+    ap_register_output_filter("H2_C2_NET_CATCH_H1", h2_c2_filter_catch_h1_out,
+                              NULL, AP_FTYPE_NETWORK);
+
+    ap_register_input_filter("H2_C2_REQUEST_IN", h2_c2_filter_request_in,
+                             NULL, AP_FTYPE_PROTOCOL);
+    ap_register_output_filter("H2_C2_RESPONSE_OUT", h2_c2_filter_response_out,
+                              NULL, AP_FTYPE_PROTOCOL);
+    ap_register_output_filter("H2_C2_TRAILERS_OUT", h2_c2_filter_trailers_out,
+                              NULL, AP_FTYPE_PROTOCOL);
+}
+
+#endif /* else AP_HAS_RESPONSE_BUCKETS */