/* 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 <assert.h>

#include <apr_strings.h>

#include <httpd.h>
#include <http_core.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_mpm.h>
#include <mod_core.h>
#include <scoreboard.h>

#include "h2_private.h"
#include "h2_push.h"
#include "h2_request.h"
#include "h2_util.h"


static apr_status_t inspect_clen(h2_request *req, const char *s)
{
    char *end;
    req->content_length = apr_strtoi64(s, &end, 10);
    return (s == end)? APR_EINVAL : APR_SUCCESS;
}

apr_status_t h2_request_rwrite(h2_request *req, apr_pool_t *pool, 
                               request_rec *r)
{
    apr_status_t status;
    const char *scheme, *authority;
    
    scheme = apr_pstrdup(pool, r->parsed_uri.scheme? r->parsed_uri.scheme
              : ap_http_scheme(r));
    authority = apr_pstrdup(pool, r->hostname);
    if (!ap_strchr_c(authority, ':') && r->server && r->server->port) {
        apr_port_t defport = apr_uri_port_of_scheme(scheme);
        if (defport != r->server->port) {
            /* port info missing and port is not default for scheme: append */
            authority = apr_psprintf(pool, "%s:%d", authority,
                                     (int)r->server->port);
        }
    }
    
    status = h2_req_make(req, pool, apr_pstrdup(pool, r->method), scheme, 
                         authority, apr_uri_unparse(pool, &r->parsed_uri, 
                                                    APR_URI_UNP_OMITSITEPART),
                         r->headers_in);
    return status;
}

apr_status_t h2_request_add_header(h2_request *req, apr_pool_t *pool, 
                                   const char *name, size_t nlen,
                                   const char *value, size_t vlen)
{
    apr_status_t status = APR_SUCCESS;
    
    if (nlen <= 0) {
        return status;
    }
    
    if (name[0] == ':') {
        /* pseudo header, see ch. 8.1.2.3, always should come first */
        if (!apr_is_empty_table(req->headers)) {
            ap_log_perror(APLOG_MARK, APLOG_ERR, 0, pool,
                          APLOGNO(02917) 
                          "h2_request(%d): pseudo header after request start",
                          req->id);
            return APR_EGENERAL;
        }
        
        if (H2_HEADER_METHOD_LEN == nlen
            && !strncmp(H2_HEADER_METHOD, name, nlen)) {
            req->method = apr_pstrndup(pool, value, vlen);
        }
        else if (H2_HEADER_SCHEME_LEN == nlen
                 && !strncmp(H2_HEADER_SCHEME, name, nlen)) {
            req->scheme = apr_pstrndup(pool, value, vlen);
        }
        else if (H2_HEADER_PATH_LEN == nlen
                 && !strncmp(H2_HEADER_PATH, name, nlen)) {
            req->path = apr_pstrndup(pool, value, vlen);
        }
        else if (H2_HEADER_AUTH_LEN == nlen
                 && !strncmp(H2_HEADER_AUTH, name, nlen)) {
            req->authority = apr_pstrndup(pool, value, vlen);
        }
        else {
            char buffer[32];
            memset(buffer, 0, 32);
            strncpy(buffer, name, (nlen > 31)? 31 : nlen);
            ap_log_perror(APLOG_MARK, APLOG_WARNING, 0, pool,
                          APLOGNO(02954) 
                          "h2_request(%d): ignoring unknown pseudo header %s",
                          req->id, buffer);
        }
    }
    else {
        /* non-pseudo header, append to work bucket of stream */
        status = h2_headers_add_h1(req->headers, pool, name, nlen, value, vlen);
    }
    
    return status;
}

apr_status_t h2_request_end_headers(h2_request *req, apr_pool_t *pool, 
                                    int eos, int push)
{
    const char *s;
    
    if (req->eoh) {
        /* already done */
        return APR_SUCCESS;
    }

    /* rfc7540, ch. 8.1.2.3:
     * - if we have :authority, it overrides any Host header 
     * - :authority MUST be ommited when converting h1->h2, so we
     *   might get a stream without, but then Host needs to be there */
    if (!req->authority) {
        const char *host = apr_table_get(req->headers, "Host");
        if (!host) {
            return APR_BADARG;
        }
        req->authority = host;
    }
    else {
        apr_table_setn(req->headers, "Host", req->authority);
    }

    s = apr_table_get(req->headers, "Content-Length");
    if (s) {
        if (inspect_clen(req, s) != APR_SUCCESS) {
            ap_log_perror(APLOG_MARK, APLOG_WARNING, APR_EINVAL, pool,
                          APLOGNO(02959) 
                          "h2_request(%d): content-length value not parsed: %s",
                          req->id, s);
            return APR_EINVAL;
        }
    }
    else {
        /* no content-length given */
        req->content_length = -1;
        if (!eos) {
            /* We have not seen a content-length and have no eos,
             * simulate a chunked encoding for our HTTP/1.1 infrastructure,
             * in case we have "H2SerializeHeaders on" here
             */
            req->chunked = 1;
            apr_table_mergen(req->headers, "Transfer-Encoding", "chunked");
        }
        else if (apr_table_get(req->headers, "Content-Type")) {
            /* If we have a content-type, but already see eos, no more
             * data will come. Signal a zero content length explicitly.
             */
            apr_table_setn(req->headers, "Content-Length", "0");
        }
    }

    req->eoh = 1;
    h2_push_policy_determine(req, pool, push);
    
    /* In the presence of trailers, force behaviour of chunked encoding */
    s = apr_table_get(req->headers, "Trailer");
    if (s && s[0]) {
        req->trailers = apr_table_make(pool, 5);
        if (!req->chunked) {
            req->chunked = 1;
            apr_table_mergen(req->headers, "Transfer-Encoding", "chunked");
        }
    }
    
    return APR_SUCCESS;
}

static apr_status_t add_h1_trailer(h2_request *req, apr_pool_t *pool, 
                                   const char *name, size_t nlen,
                                   const char *value, size_t vlen)
{
    char *hname, *hvalue;
    
    if (h2_req_ignore_trailer(name, nlen)) {
        return APR_SUCCESS;
    }
    
    hname = apr_pstrndup(pool, name, nlen);
    hvalue = apr_pstrndup(pool, value, vlen);
    h2_util_camel_case_header(hname, nlen);

    apr_table_mergen(req->trailers, hname, hvalue);
    
    return APR_SUCCESS;
}


apr_status_t h2_request_add_trailer(h2_request *req, apr_pool_t *pool,
                                    const char *name, size_t nlen,
                                    const char *value, size_t vlen)
{
    if (!req->trailers) {
        ap_log_perror(APLOG_MARK, APLOG_DEBUG, APR_EINVAL, pool, APLOGNO(03059)
                      "h2_request(%d): unanounced trailers",
                      req->id);
        return APR_EINVAL;
    }
    if (nlen == 0 || name[0] == ':') {
        ap_log_perror(APLOG_MARK, APLOG_DEBUG, APR_EINVAL, pool, APLOGNO(03060)
                      "h2_request(%d): pseudo header in trailer",
                      req->id);
        return APR_EINVAL;
    }
    return add_h1_trailer(req, pool, name, nlen, value, vlen);
}

h2_request *h2_request_clone(apr_pool_t *p, const h2_request *src)
{
    h2_request *dst = apr_pmemdup(p, src, sizeof(*dst));
    dst->method       = apr_pstrdup(p, src->method);
    dst->scheme       = apr_pstrdup(p, src->scheme);
    dst->authority    = apr_pstrdup(p, src->authority);
    dst->path         = apr_pstrdup(p, src->path);
    dst->headers      = apr_table_clone(p, src->headers);
    if (src->trailers) {
        dst->trailers = apr_table_clone(p, src->trailers);
    }
    return dst;
}

request_rec *h2_request_create_rec(const h2_request *req, conn_rec *c)
{
    int access_status = HTTP_OK;    
    
    request_rec *r = ap_create_request(c);

    r->headers_in = apr_table_clone(r->pool, req->headers);

    ap_run_pre_read_request(r, c);
    
    /* Time to populate r with the data we have. */
    r->request_time = req->request_time;
    r->method = req->method;
    /* Provide quick information about the request method as soon as known */
    r->method_number = ap_method_number_of(r->method);
    if (r->method_number == M_GET && r->method[0] == 'H') {
        r->header_only = 1;
    }

    ap_parse_uri(r, req->path);
    r->protocol = "HTTP/2.0";
    r->proto_num = HTTP_VERSION(2, 0);

    r->the_request = apr_psprintf(r->pool, "%s %s %s", 
                                  r->method, req->path, r->protocol);
    
    /* update what we think the virtual host is based on the headers we've
     * now read. may update status.
     * Leave r->hostname empty, vhost will parse if form our Host: header,
     * otherwise we get complains about port numbers.
     */
    r->hostname = NULL;
    ap_update_vhost_from_headers(r);
    
    /* we may have switched to another server */
    r->per_dir_config = r->server->lookup_defaults;
    
    /*
     * Add the HTTP_IN filter here to ensure that ap_discard_request_body
     * called by ap_die and by ap_send_error_response works correctly on
     * status codes that do not cause the connection to be dropped and
     * in situations where the connection should be kept alive.
     */
    ap_add_input_filter_handle(ap_http_input_filter_handle,
                               NULL, r, r->connection);
    
    if (access_status != HTTP_OK
        || (access_status = ap_run_post_read_request(r))) {
        /* Request check post hooks failed. An example of this would be a
         * request for a vhost where h2 is disabled --> 421.
         */
        ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c, APLOGNO(03367)
                      "h2_request(%d): access_status=%d, request_create failed",
                      req->id, access_status);
        ap_die(access_status, r);
        ap_update_child_status(c->sbh, SERVER_BUSY_LOG, r);
        ap_run_log_transaction(r);
        r = NULL;
        goto traceout;
    }
    
    AP_READ_REQUEST_SUCCESS((uintptr_t)r, (char *)r->method, 
                            (char *)r->uri, (char *)r->server->defn_name, 
                            r->status);
    return r;
traceout:
    AP_READ_REQUEST_FAILURE((uintptr_t)r);
    return r;
}