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/* Copyright 2015 greenbytes GmbH (https://www.greenbytes.de)
*
* Licensed 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 <apr_strings.h>
#include <httpd.h>
#include <http_core.h>
#include <http_connection.h>
#include <http_protocol.h>
#include <http_log.h>
#include "h2_private.h"
#include "h2_alt_svc.h"
#include "h2_ctx.h"
#include "h2_config.h"
#include "h2_h2.h"
#include "h2_util.h"
static int h2_alt_svc_handler(request_rec *r);
void h2_alt_svc_register_hooks(void)
{
ap_hook_post_read_request(h2_alt_svc_handler, NULL, NULL, APR_HOOK_MIDDLE);
}
/**
* Parse an Alt-Svc specifier as described in "HTTP Alternative Services"
* (https://tools.ietf.org/html/draft-ietf-httpbis-alt-svc-04)
* with the following changes:
* - do not percent encode token values
* - do not use quotation marks
*/
h2_alt_svc *h2_alt_svc_parse(const char *s, apr_pool_t *pool)
{
const char *sep = ap_strchr_c(s, '=');
if (sep) {
const char *alpn = apr_pstrmemdup(pool, s, sep - s);
const char *host = NULL;
int port = 0;
s = sep + 1;
sep = ap_strchr_c(s, ':'); /* mandatory : */
if (sep) {
if (sep != s) { /* optional host */
host = apr_pstrmemdup(pool, s, sep - s);
}
s = sep + 1;
if (*s) { /* must be a port number */
port = (int)apr_atoi64(s);
if (port > 0 && port < (0x1 << 16)) {
h2_alt_svc *as = apr_pcalloc(pool, sizeof(*as));
as->alpn = alpn;
as->host = host;
as->port = port;
return as;
}
}
}
}
return NULL;
}
#define h2_alt_svc_IDX(list, i) ((h2_alt_svc**)(list)->elts)[i]
static int h2_alt_svc_handler(request_rec *r)
{
const h2_config *cfg;
int i;
if (r->connection->keepalives > 0) {
/* Only announce Alt-Svc on the first response */
return DECLINED;
}
if (h2_ctx_rget(r)) {
return DECLINED;
}
cfg = h2_config_sget(r->server);
if (r->hostname && cfg && cfg->alt_svcs && cfg->alt_svcs->nelts > 0) {
const char *alt_svc_used = apr_table_get(r->headers_in, "Alt-Svc-Used");
if (!alt_svc_used) {
/* We have alt-svcs defined and client is not already using
* one, announce the services that were configured and match.
* The security of this connection determines if we allow
* other host names or ports only.
*/
const char *alt_svc = "";
const char *svc_ma = "";
int secure = h2_h2_is_tls(r->connection);
int ma = h2_config_geti(cfg, H2_CONF_ALT_SVC_MAX_AGE);
if (ma >= 0) {
svc_ma = apr_psprintf(r->pool, "; ma=%d", ma);
}
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(03043)
"h2_alt_svc: announce %s for %s:%d",
(secure? "secure" : "insecure"),
r->hostname, (int)r->server->port);
for (i = 0; i < cfg->alt_svcs->nelts; ++i) {
h2_alt_svc *as = h2_alt_svc_IDX(cfg->alt_svcs, i);
const char *ahost = as->host;
if (ahost && !apr_strnatcasecmp(ahost, r->hostname)) {
ahost = NULL;
}
if (secure || !ahost) {
alt_svc = apr_psprintf(r->pool, "%s%s%s=\"%s:%d\"%s",
alt_svc,
(*alt_svc? ", " : ""), as->alpn,
ahost? ahost : "", as->port,
svc_ma);
}
}
if (*alt_svc) {
apr_table_setn(r->headers_out, "Alt-Svc", alt_svc);
}
}
}
return DECLINED;
}