/* 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_mplx.h"
#include "h2_request.h"
#include "h2_task.h"
#include "h2_util.h"


h2_request *h2_request_create(int id, apr_pool_t *pool)
{
    return h2_request_createn(id, pool, NULL, NULL, NULL, NULL, NULL);
}

h2_request *h2_request_createn(int id, apr_pool_t *pool,
                               const char *method, const char *scheme,
                               const char *authority, const char *path,
                               apr_table_t *header)
{
    h2_request *req = apr_pcalloc(pool, sizeof(h2_request));
    
    req->id             = id;
    req->method         = method;
    req->scheme         = scheme;
    req->authority      = authority;
    req->path           = path;
    req->headers        = header? header : apr_table_make(pool, 10);
    req->request_time   = apr_time_now();

    return req;
}

void h2_request_destroy(h2_request *req)
{
}

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;
}

static apr_status_t add_h1_header(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_header(name, nlen)) {
        return APR_SUCCESS;
    }
    else if (H2_HD_MATCH_LIT("cookie", name, nlen)) {
        const char *existing = apr_table_get(req->headers, "cookie");
        if (existing) {
            char *nval;
            
            /* Cookie header come separately in HTTP/2, but need
             * to be merged by "; " (instead of default ", ")
             */
            hvalue = apr_pstrndup(pool, value, vlen);
            nval = apr_psprintf(pool, "%s; %s", existing, hvalue);
            apr_table_setn(req->headers, "Cookie", nval);
            return APR_SUCCESS;
        }
    }
    else if (H2_HD_MATCH_LIT("host", name, nlen)) {
        if (apr_table_get(req->headers, "Host")) {
            return APR_SUCCESS; /* ignore duplicate */
        }
    }
    
    hname = apr_pstrndup(pool, name, nlen);
    hvalue = apr_pstrndup(pool, value, vlen);
    h2_util_camel_case_header(hname, nlen);
    apr_table_mergen(req->headers, hname, hvalue);
    
    return APR_SUCCESS;
}

typedef struct {
    h2_request *req;
    apr_pool_t *pool;
} h1_ctx;

static int set_h1_header(void *ctx, const char *key, const char *value)
{
    h1_ctx *x = ctx;
    size_t klen = strlen(key);
    if (!h2_req_ignore_header(key, klen)) {
        add_h1_header(x->req, x->pool, key, klen, value, strlen(value));
    }
    return 1;
}

static apr_status_t add_all_h1_header(h2_request *req, apr_pool_t *pool, 
                                      apr_table_t *header)
{
    h1_ctx x;
    x.req = req;
    x.pool = pool;
    apr_table_do(set_h1_header, &x, header, NULL);
    return APR_SUCCESS;
}


apr_status_t h2_request_rwrite(h2_request *req, request_rec *r)
{
    apr_status_t status;
    
    req->method    = r->method;
    req->scheme    = (r->parsed_uri.scheme? r->parsed_uri.scheme
                      : ap_http_scheme(r));
    req->authority = r->hostname;
    req->path      = apr_uri_unparse(r->pool, &r->parsed_uri, 
                                     APR_URI_UNP_OMITSITEPART);

    if (!ap_strchr_c(req->authority, ':') && r->server) {
        req->authority = apr_psprintf(r->pool, "%s:%d", req->authority,
                                      (int)r->server->port);
    }
    
    AP_DEBUG_ASSERT(req->scheme);
    AP_DEBUG_ASSERT(req->authority);
    AP_DEBUG_ASSERT(req->path);
    AP_DEBUG_ASSERT(req->method);

    status = add_all_h1_header(req, r->pool, r->headers_in);

    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, status, r,
                  "h2_request(%d): rwrite %s host=%s://%s%s",
                  req->id, req->method, req->scheme, req->authority, req->path);
                  
    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 = add_h1_header(req, pool, name, nlen, value, vlen);
    }
    
    return status;
}

apr_status_t h2_request_end_headers(h2_request *req, apr_pool_t *pool, int eos)
{
    const char *s;
    
    if (req->eoh) {
        return APR_EINVAL;
    }

    /* Always set the "Host" header from :authority, see rfc7540, ch. 8.1.2.3 */
    if (!req->authority) {
        return APR_BADARG;
    }
    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;
    
    /* 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,
                      "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,
                      "h2_request(%d): pseudo header in trailer",
                      req->id);
        return APR_EINVAL;
    }
    return add_h1_trailer(req, pool, name, nlen, value, vlen);
}

#define OPT_COPY(p, s)  ((s)? apr_pstrdup(p, s) : NULL)

void h2_request_copy(apr_pool_t *p, h2_request *dst, const h2_request *src)
{
    /* keep the dst id */
    dst->method         = OPT_COPY(p, src->method);
    dst->scheme         = OPT_COPY(p, src->scheme);
    dst->authority      = OPT_COPY(p, src->authority);
    dst->path           = OPT_COPY(p, src->path);
    dst->headers        = apr_table_clone(p, src->headers);
    dst->content_length = src->content_length;
    dst->chunked        = src->chunked;
    dst->eoh            = src->eoh;
}

request_rec *h2_request_create_rec(const h2_request *req, conn_rec *conn)
{
    request_rec *r;
    apr_pool_t *p;
    int access_status = HTTP_OK;    
    
    apr_pool_create(&p, conn->pool);
    apr_pool_tag(p, "request");
    r = apr_pcalloc(p, sizeof(request_rec));
    AP_READ_REQUEST_ENTRY((intptr_t)r, (uintptr_t)conn);
    r->pool            = p;
    r->connection      = conn;
    r->server          = conn->base_server;
    
    r->user            = NULL;
    r->ap_auth_type    = NULL;
    
    r->allowed_methods = ap_make_method_list(p, 2);
    
    r->headers_in      = apr_table_copy(r->pool, req->headers);
    r->trailers_in     = apr_table_make(r->pool, 5);
    r->subprocess_env  = apr_table_make(r->pool, 25);
    r->headers_out     = apr_table_make(r->pool, 12);
    r->err_headers_out = apr_table_make(r->pool, 5);
    r->trailers_out    = apr_table_make(r->pool, 5);
    r->notes           = apr_table_make(r->pool, 5);
    
    r->request_config  = ap_create_request_config(r->pool);
    /* Must be set before we run create request hook */
    
    r->proto_output_filters = conn->output_filters;
    r->output_filters  = r->proto_output_filters;
    r->proto_input_filters = conn->input_filters;
    r->input_filters   = r->proto_input_filters;
    ap_run_create_request(r);
    r->per_dir_config  = r->server->lookup_defaults;
    
    r->sent_bodyct     = 0;                      /* bytect isn't for body */
    
    r->read_length     = 0;
    r->read_body       = REQUEST_NO_BODY;
    
    r->status          = HTTP_OK;  /* Until further notice */
    r->header_only     = 0;
    r->the_request     = NULL;
    
    /* Begin by presuming any module can make its own path_info assumptions,
     * until some module interjects and changes the value.
     */
    r->used_path_info = AP_REQ_DEFAULT_PATH_INFO;
    
    r->useragent_addr = conn->client_addr;
    r->useragent_ip = conn->client_ip;
    
    ap_run_pre_read_request(r, conn);
    
    /* 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 = (char*)"HTTP/2";
    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_die(access_status, r);
        ap_update_child_status(conn->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;
}