http.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2006, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*!
 * \file
 * \brief http server for AMI access
 *
 * \author Mark Spencer <markster@digium.com>
 *
 * This program implements a tiny http server
 * and was inspired by micro-httpd by Jef Poskanzer
 *
 * \extref GMime http://spruce.sourceforge.net/gmime/
 *
 * \ref AstHTTP - AMI over the http protocol
 */

/*** MODULEINFO
   <support_level>core</support_level>
 ***/

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 410382 $")

#include <time.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/signal.h>
#include <fcntl.h>

#include "asterisk/paths.h"   /* use ast_config_AST_DATA_DIR */
#include "asterisk/network.h"
#include "asterisk/cli.h"
#include "asterisk/tcptls.h"
#include "asterisk/http.h"
#include "asterisk/utils.h"
#include "asterisk/strings.h"
#include "asterisk/config.h"
#include "asterisk/stringfields.h"
#include "asterisk/ast_version.h"
#include "asterisk/manager.h"
#include "asterisk/_private.h"
#include "asterisk/astobj2.h"

#define MAX_PREFIX 80
#define DEFAULT_SESSION_LIMIT 100

#define DEFAULT_HTTP_PORT 8088
#define DEFAULT_HTTPS_PORT 8089

/* See http.h for more information about the SSL implementation */
#if defined(HAVE_OPENSSL) && (defined(HAVE_FUNOPEN) || defined(HAVE_FOPENCOOKIE))
#define  DO_SSL   /* comment in/out if you want to support ssl */
#endif

static int session_limit = DEFAULT_SESSION_LIMIT;
static int session_count = 0;

static struct ast_tls_config http_tls_cfg;

static void *httpd_helper_thread(void *arg);

/*!
 * we have up to two accepting threads, one for http, one for https
 */
static struct ast_tcptls_session_args http_desc = {
   .accept_fd = -1,
   .master = AST_PTHREADT_NULL,
   .tls_cfg = NULL,
   .poll_timeout = -1,
   .name = "http server",
   .accept_fn = ast_tcptls_server_root,
   .worker_fn = httpd_helper_thread,
};

static struct ast_tcptls_session_args https_desc = {
   .accept_fd = -1,
   .master = AST_PTHREADT_NULL,
   .tls_cfg = &http_tls_cfg,
   .poll_timeout = -1,
   .name = "https server",
   .accept_fn = ast_tcptls_server_root,
   .worker_fn = httpd_helper_thread,
};

static AST_RWLIST_HEAD_STATIC(uris, ast_http_uri); /*!< list of supported handlers */

/* all valid URIs must be prepended by the string in prefix. */
static char prefix[MAX_PREFIX];
static int enablestatic;

/*! \brief Limit the kinds of files we're willing to serve up */
static struct {
   const char *ext;
   const char *mtype;
} mimetypes[] = {
   { "png", "image/png" },
   { "xml", "text/xml" },
   { "jpg", "image/jpeg" },
   { "js", "application/x-javascript" },
   { "wav", "audio/x-wav" },
   { "mp3", "audio/mpeg" },
   { "svg", "image/svg+xml" },
   { "svgz", "image/svg+xml" },
   { "gif", "image/gif" },
   { "html", "text/html" },
   { "htm", "text/html" },
   { "css", "text/css" },
   { "cnf", "text/plain" },
   { "cfg", "text/plain" },
   { "bin", "application/octet-stream" },
   { "sbn", "application/octet-stream" },
   { "ld", "application/octet-stream" },
};

struct http_uri_redirect {
   AST_LIST_ENTRY(http_uri_redirect) entry;
   char *dest;
   char target[0];
};

static AST_RWLIST_HEAD_STATIC(uri_redirects, http_uri_redirect);

static const struct ast_cfhttp_methods_text {
   enum ast_http_method method;
   const char *text;
} ast_http_methods_text[] = {
   { AST_HTTP_UNKNOWN,     "UNKNOWN" },
   { AST_HTTP_GET,         "GET" },
   { AST_HTTP_POST,        "POST" },
   { AST_HTTP_HEAD,        "HEAD" },
   { AST_HTTP_PUT,         "PUT" },
};

const char *ast_get_http_method(enum ast_http_method method)
{
   int x;

   for (x = 0; x < ARRAY_LEN(ast_http_methods_text); x++) {
      if (ast_http_methods_text[x].method == method) {
         return ast_http_methods_text[x].text;
      }
   }

   return NULL;
}

const char *ast_http_ftype2mtype(const char *ftype)
{
   int x;

   if (ftype) {
      for (x = 0; x < ARRAY_LEN(mimetypes); x++) {
         if (!strcasecmp(ftype, mimetypes[x].ext)) {
            return mimetypes[x].mtype;
         }
      }
   }
   return NULL;
}

uint32_t ast_http_manid_from_vars(struct ast_variable *headers)
{
   uint32_t mngid = 0;
   struct ast_variable *v, *cookies;

   cookies = ast_http_get_cookies(headers);
   for (v = cookies; v; v = v->next) {
      if (!strcasecmp(v->name, "mansession_id")) {
         sscanf(v->value, "%30x", &mngid);
         break;
      }
   }
   ast_variables_destroy(cookies);
   return mngid;
}

void ast_http_prefix(char *buf, int len)
{
   if (buf) {
      ast_copy_string(buf, prefix, len);
   }
}

static int static_callback(struct ast_tcptls_session_instance *ser,
   const struct ast_http_uri *urih, const char *uri,
   enum ast_http_method method, struct ast_variable *get_vars,
   struct ast_variable *headers)
{
   char *path;
   const char *ftype;
   const char *mtype;
   char wkspace[80];
   struct stat st;
   int len;
   int fd;
   struct ast_str *http_header;
   struct timeval tv;
   struct ast_tm tm;
   char timebuf[80], etag[23];
   struct ast_variable *v;
   int not_modified = 0;

   if (method != AST_HTTP_GET && method != AST_HTTP_HEAD) {
      ast_http_error(ser, 501, "Not Implemented", "Attempt to use unimplemented / unsupported method");
      return -1;
   }

   /* Yuck.  I'm not really sold on this, but if you don't deliver static content it makes your configuration
      substantially more challenging, but this seems like a rather irritating feature creep on Asterisk. */
   if (!enablestatic || ast_strlen_zero(uri)) {
      goto out403;
   }

   /* Disallow any funny filenames at all (checking first character only??) */
   if ((uri[0] < 33) || strchr("./|~@#$%^&*() \t", uri[0])) {
      goto out403;
   }

   if (strstr(uri, "/..")) {
      goto out403;
   }

   if ((ftype = strrchr(uri, '.'))) {
      ftype++;
   }

   if (!(mtype = ast_http_ftype2mtype(ftype))) {
      snprintf(wkspace, sizeof(wkspace), "text/%s", S_OR(ftype, "plain"));
      mtype = wkspace;
   }

   /* Cap maximum length */
   if ((len = strlen(uri) + strlen(ast_config_AST_DATA_DIR) + strlen("/static-http/") + 5) > 1024) {
      goto out403;
   }

   path = ast_alloca(len);
   sprintf(path, "%s/static-http/%s", ast_config_AST_DATA_DIR, uri);
   if (stat(path, &st)) {
      goto out404;
   }

   if (S_ISDIR(st.st_mode)) {
      goto out404;
   }

   if (strstr(path, "/private/") && !astman_is_authed(ast_http_manid_from_vars(headers))) {
      goto out403;
   }

   fd = open(path, O_RDONLY);
   if (fd < 0) {
      goto out403;
   }

   /* make "Etag:" http header value */
   snprintf(etag, sizeof(etag), "\"%ld\"", (long)st.st_mtime);

   /* make "Last-Modified:" http header value */
   tv.tv_sec = st.st_mtime;
   tv.tv_usec = 0;
   ast_strftime(timebuf, sizeof(timebuf), "%a, %d %b %Y %H:%M:%S GMT", ast_localtime(&tv, &tm, "GMT"));

   /* check received "If-None-Match" request header and Etag value for file */
   for (v = headers; v; v = v->next) {
      if (!strcasecmp(v->name, "If-None-Match")) {
         if (!strcasecmp(v->value, etag)) {
            not_modified = 1;
         }
         break;
      }
   }

   if ( (http_header = ast_str_create(255)) == NULL) {
      close(fd);
      return -1;
   }

   ast_str_set(&http_header, 0, "Content-type: %s\r\n"
      "ETag: %s\r\n"
      "Last-Modified: %s\r\n",
      mtype,
      etag,
      timebuf);

   /* ast_http_send() frees http_header, so we don't need to do it before returning */
   if (not_modified) {
      ast_http_send(ser, method, 304, "Not Modified", http_header, NULL, 0, 1);
   } else {
      ast_http_send(ser, method, 200, NULL, http_header, NULL, fd, 1); /* static content flag is set */
   }
   close(fd);
   return 0;

out404:
   ast_http_error(ser, 404, "Not Found", "The requested URL was not found on this server.");
   return -1;

out403:
   ast_http_error(ser, 403, "Access Denied", "You do not have permission to access the requested URL.");
   return -1;
}

static int httpstatus_callback(struct ast_tcptls_session_instance *ser,
   const struct ast_http_uri *urih, const char *uri,
   enum ast_http_method method, struct ast_variable *get_vars,
   struct ast_variable *headers)
{
   struct ast_str *out;
   struct ast_variable *v, *cookies = NULL;

   if (method != AST_HTTP_GET && method != AST_HTTP_HEAD) {
      ast_http_error(ser, 501, "Not Implemented", "Attempt to use unimplemented / unsupported method");
      return -1;
   }

   if ( (out = ast_str_create(512)) == NULL) {
      return -1;
   }

   ast_str_append(&out, 0,
      "<title>Asterisk HTTP Status</title>\r\n"
      "<body bgcolor=\"#ffffff\">\r\n"
      "<table bgcolor=\"#f1f1f1\" align=\"center\"><tr><td bgcolor=\"#e0e0ff\" colspan=\"2\" width=\"500\">\r\n"
      "<h2>&nbsp;&nbsp;Asterisk&trade; HTTP Status</h2></td></tr>\r\n");

   ast_str_append(&out, 0, "<tr><td><i>Prefix</i></td><td><b>%s</b></td></tr>\r\n", prefix);
   ast_str_append(&out, 0, "<tr><td><i>Bind Address</i></td><td><b>%s</b></td></tr>\r\n",
             ast_sockaddr_stringify_addr(&http_desc.old_address));
   ast_str_append(&out, 0, "<tr><td><i>Bind Port</i></td><td><b>%s</b></td></tr>\r\n",
             ast_sockaddr_stringify_port(&http_desc.old_address));
   if (http_tls_cfg.enabled) {
      ast_str_append(&out, 0, "<tr><td><i>SSL Bind Port</i></td><td><b>%s</b></td></tr>\r\n",
                ast_sockaddr_stringify_port(&https_desc.old_address));
   }
   ast_str_append(&out, 0, "<tr><td colspan=\"2\"><hr></td></tr>\r\n");
   for (v = get_vars; v; v = v->next) {
      ast_str_append(&out, 0, "<tr><td><i>Submitted GET Variable '%s'</i></td><td>%s</td></tr>\r\n", v->name, v->value);
   }
   ast_str_append(&out, 0, "<tr><td colspan=\"2\"><hr></td></tr>\r\n");

   cookies = ast_http_get_cookies(headers);
   for (v = cookies; v; v = v->next) {
      ast_str_append(&out, 0, "<tr><td><i>Cookie '%s'</i></td><td>%s</td></tr>\r\n", v->name, v->value);
   }
   ast_variables_destroy(cookies);

   ast_str_append(&out, 0, "</table><center><font size=\"-1\"><i>Asterisk and Digium are registered trademarks of Digium, Inc.</i></font></center></body>\r\n");
   ast_http_send(ser, method, 200, NULL, NULL, out, 0, 0);
   return 0;
}

static struct ast_http_uri statusuri = {
   .callback = httpstatus_callback,
   .description = "Asterisk HTTP General Status",
   .uri = "httpstatus",
   .has_subtree = 0,
   .data = NULL,
   .key = __FILE__,
};

static struct ast_http_uri staticuri = {
   .callback = static_callback,
   .description = "Asterisk HTTP Static Delivery",
   .uri = "static",
   .has_subtree = 1,
   .data = NULL,
   .key= __FILE__,
};


/* send http/1.1 response */
/* free content variable and close socket*/
void ast_http_send(struct ast_tcptls_session_instance *ser,
   enum ast_http_method method, int status_code, const char *status_title,
   struct ast_str *http_header, struct ast_str *out, const int fd,
   unsigned int static_content)
{
   struct timeval now = ast_tvnow();
   struct ast_tm tm;
   char timebuf[80];
   int content_length = 0;

   if (!ser || 0 == ser->f) {
      return;
   }

   ast_strftime(timebuf, sizeof(timebuf), "%a, %d %b %Y %H:%M:%S GMT", ast_localtime(&now, &tm, "GMT"));

   /* calc content length */
   if (out) {
      content_length += strlen(ast_str_buffer(out));
   }

   if (fd) {
      content_length += lseek(fd, 0, SEEK_END);
      lseek(fd, 0, SEEK_SET);
   }

   /* send http header */
   fprintf(ser->f, "HTTP/1.1 %d %s\r\n"
      "Server: Asterisk/%s\r\n"
      "Date: %s\r\n"
      "Connection: close\r\n"
      "%s"
      "Content-Length: %d\r\n"
      "%s"
      "\r\n",
      status_code, status_title ? status_title : "OK",
      ast_get_version(),
      timebuf,
      static_content ? "" : "Cache-Control: no-cache, no-store\r\n",
      content_length,
      http_header ? ast_str_buffer(http_header) : ""
      );

   /* send content */
   if (method != AST_HTTP_HEAD || status_code >= 400) {
      if (out) {
         fprintf(ser->f, "%s", ast_str_buffer(out));
      }

      if (fd) {
         char buf[256];
         int len;
         while ((len = read(fd, buf, sizeof(buf))) > 0) {
            if (fwrite(buf, len, 1, ser->f) != 1) {
               ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
               break;
            }
         }
      }
   }

   if (http_header) {
      ast_free(http_header);
   }
   if (out) {
      ast_free(out);
   }

   fclose(ser->f);
   ser->f = 0;
   return;
}

/* Send http "401 Unauthorized" responce and close socket*/
void ast_http_auth(struct ast_tcptls_session_instance *ser, const char *realm,
   const unsigned long nonce, const unsigned long opaque, int stale,
   const char *text)
{
   struct ast_str *http_headers = ast_str_create(128);
   struct ast_str *out = ast_str_create(512);

   if (!http_headers || !out) {
      ast_free(http_headers);
      ast_free(out);
      return;
   }

   ast_str_set(&http_headers, 0,
      "WWW-authenticate: Digest algorithm=MD5, realm=\"%s\", nonce=\"%08lx\", qop=\"auth\", opaque=\"%08lx\"%s\r\n"
      "Content-type: text/html\r\n",
      realm ? realm : "Asterisk",
      nonce,
      opaque,
      stale ? ", stale=true" : "");

   ast_str_set(&out, 0,
      "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\r\n"
      "<html><head>\r\n"
      "<title>401 Unauthorized</title>\r\n"
      "</head><body>\r\n"
      "<h1>401 Unauthorized</h1>\r\n"
      "<p>%s</p>\r\n"
      "<hr />\r\n"
      "<address>Asterisk Server</address>\r\n"
      "</body></html>\r\n",
      text ? text : "");

   ast_http_send(ser, AST_HTTP_UNKNOWN, 401, "Unauthorized", http_headers, out, 0, 0);
   return;
}

/* send http error response and close socket*/
void ast_http_error(struct ast_tcptls_session_instance *ser, int status_code, const char *status_title, const char *text)
{
   struct ast_str *http_headers = ast_str_create(40);
   struct ast_str *out = ast_str_create(256);

   if (!http_headers || !out) {
      ast_free(http_headers);
      ast_free(out);
      return;
   }

   ast_str_set(&http_headers, 0, "Content-type: text/html\r\n");

   ast_str_set(&out, 0,
      "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\r\n"
      "<html><head>\r\n"
      "<title>%d %s</title>\r\n"
      "</head><body>\r\n"
      "<h1>%s</h1>\r\n"
      "<p>%s</p>\r\n"
      "<hr />\r\n"
      "<address>Asterisk Server</address>\r\n"
      "</body></html>\r\n",
         status_code, status_title, status_title, text);

   ast_http_send(ser, AST_HTTP_UNKNOWN, status_code, status_title, http_headers, out, 0, 0);
   return;
}

/*! \brief
 * Link the new uri into the list.
 *
 * They are sorted by length of
 * the string, not alphabetically. Duplicate entries are not replaced,
 * but the insertion order (using <= and not just <) makes sure that
 * more recent insertions hide older ones.
 * On a lookup, we just scan the list and stop at the first matching entry.
 */
int ast_http_uri_link(struct ast_http_uri *urih)
{
   struct ast_http_uri *uri;
   int len = strlen(urih->uri);

   AST_RWLIST_WRLOCK(&uris);

   if ( AST_RWLIST_EMPTY(&uris) || strlen(AST_RWLIST_FIRST(&uris)->uri) <= len ) {
      AST_RWLIST_INSERT_HEAD(&uris, urih, entry);
      AST_RWLIST_UNLOCK(&uris);
      return 0;
   }

   AST_RWLIST_TRAVERSE(&uris, uri, entry) {
      if (AST_RWLIST_NEXT(uri, entry) &&
         strlen(AST_RWLIST_NEXT(uri, entry)->uri) <= len) {
         AST_RWLIST_INSERT_AFTER(&uris, uri, urih, entry);
         AST_RWLIST_UNLOCK(&uris);

         return 0;
      }
   }

   AST_RWLIST_INSERT_TAIL(&uris, urih, entry);

   AST_RWLIST_UNLOCK(&uris);

   return 0;
}

void ast_http_uri_unlink(struct ast_http_uri *urih)
{
   AST_RWLIST_WRLOCK(&uris);
   AST_RWLIST_REMOVE(&uris, urih, entry);
   AST_RWLIST_UNLOCK(&uris);
}

void ast_http_uri_unlink_all_with_key(const char *key)
{
   struct ast_http_uri *urih;
   AST_RWLIST_WRLOCK(&uris);
   AST_RWLIST_TRAVERSE_SAFE_BEGIN(&uris, urih, entry) {
      if (!strcmp(urih->key, key)) {
         AST_RWLIST_REMOVE_CURRENT(entry);
         if (urih->dmallocd) {
            ast_free(urih->data);
         }
         if (urih->mallocd) {
            ast_free(urih);
         }
      }
   }
   AST_RWLIST_TRAVERSE_SAFE_END;
   AST_RWLIST_UNLOCK(&uris);
}

/*
 * Decode special characters in http uri.
 * We have ast_uri_decode to handle %XX sequences, but spaces
 * are encoded as a '+' so we need to replace them beforehand.
 */
static void http_decode(char *s)
{
   char *t;

   for (t = s; *t; t++) {
      if (*t == '+') {
         *t = ' ';
      }
   }

   ast_uri_decode(s);
}

#define MAX_POST_CONTENT 1025

/*
 * get post variables from client Request Entity-Body, if content type is
 * application/x-www-form-urlencoded
 */
struct ast_variable *ast_http_get_post_vars(
   struct ast_tcptls_session_instance *ser, struct ast_variable *headers)
{
   int content_length = 0;
   struct ast_variable *v, *post_vars=NULL, *prev = NULL;
   char *buf, *var, *val;
   int res;

   for (v = headers; v; v = v->next) {
      if (!strcasecmp(v->name, "Content-Type")) {
         if (strcasecmp(v->value, "application/x-www-form-urlencoded")) {
            return NULL;
         }
         break;
      }
   }

   for (v = headers; v; v = v->next) {
      if (!strcasecmp(v->name, "Content-Length")) {
         content_length = atoi(v->value);
         break;
      }
   }

   if (content_length <= 0) {
      return NULL;
   }

   if (content_length > MAX_POST_CONTENT - 1) {
      ast_log(LOG_WARNING, "Excessively long HTTP content. %d is greater than our max of %d\n",
            content_length, MAX_POST_CONTENT);
      ast_http_send(ser, AST_HTTP_POST, 413, "Request Entity Too Large", NULL, NULL, 0, 0);
      return NULL;
   }

   buf = ast_malloc(content_length + 1);
   if (!buf) {
      return NULL;
   }

   res = fread(buf, 1, content_length, ser->f);
   if (res < content_length) {
      /* Error, distinguishable by ferror() or feof(), but neither
       * is good. */
      goto done;
   }
   buf[content_length] = '\0';

   while ((val = strsep(&buf, "&"))) {
      var = strsep(&val, "=");
      if (val) {
         http_decode(val);
      } else  {
         val = "";
      }
      http_decode(var);
      if ((v = ast_variable_new(var, val, ""))) {
         if (post_vars) {
            prev->next = v;
         } else {
            post_vars = v;
         }
         prev = v;
      }
   }

done:
   ast_free(buf);
   return post_vars;
}

static int handle_uri(struct ast_tcptls_session_instance *ser, char *uri,
   enum ast_http_method method, struct ast_variable *headers)
{
   char *c;
   int res = -1;
   char *params = uri;
   struct ast_http_uri *urih = NULL;
   int l;
   struct ast_variable *get_vars = NULL, *v, *prev = NULL;
   struct http_uri_redirect *redirect;

   ast_debug(2, "HTTP Request URI is %s \n", uri);

   strsep(&params, "?");
   /* Extract arguments from the request and store them in variables. */
   if (params) {
      char *var, *val;

      while ((val = strsep(&params, "&"))) {
         var = strsep(&val, "=");
         if (val) {
            http_decode(val);
         } else  {
            val = "";
         }
         http_decode(var);
         if ((v = ast_variable_new(var, val, ""))) {
            if (get_vars) {
               prev->next = v;
            } else {
               get_vars = v;
            }
            prev = v;
         }
      }
   }
   http_decode(uri);

   AST_RWLIST_RDLOCK(&uri_redirects);
   AST_RWLIST_TRAVERSE(&uri_redirects, redirect, entry) {
      if (!strcasecmp(uri, redirect->target)) {
         struct ast_str *http_header = ast_str_create(128);
         ast_str_set(&http_header, 0, "Location: %s\r\n", redirect->dest);
         ast_http_send(ser, method, 302, "Moved Temporarily", http_header, NULL, 0, 0);

         break;
      }
   }
   AST_RWLIST_UNLOCK(&uri_redirects);
   if (redirect) {
      goto cleanup;
   }

   /* We want requests to start with the (optional) prefix and '/' */
   l = strlen(prefix);
   if (!strncasecmp(uri, prefix, l) && uri[l] == '/') {
      uri += l + 1;
      /* scan registered uris to see if we match one. */
      AST_RWLIST_RDLOCK(&uris);
      AST_RWLIST_TRAVERSE(&uris, urih, entry) {
         ast_debug(2, "match request [%s] with handler [%s] len %d\n", uri, urih->uri, l);
         l = strlen(urih->uri);
         c = uri + l;   /* candidate */
         if (strncasecmp(urih->uri, uri, l) /* no match */
             || (*c && *c != '/')) { /* substring */
            continue;
         }
         if (*c == '/') {
            c++;
         }
         if (!*c || urih->has_subtree) {
            uri = c;
            break;
         }
      }
      AST_RWLIST_UNLOCK(&uris);
   }
   if (urih) {
      res = urih->callback(ser, urih, uri, method, get_vars, headers);
   } else {
      ast_http_error(ser, 404, "Not Found", "The requested URL was not found on this server.");
   }

cleanup:
   ast_variables_destroy(get_vars);
   return res;
}

#ifdef DO_SSL
#if defined(HAVE_FUNOPEN)
#define HOOK_T int
#define LEN_T int
#else
#define HOOK_T ssize_t
#define LEN_T size_t
#endif

/*!
 * replacement read/write functions for SSL support.
 * We use wrappers rather than SSL_read/SSL_write directly so
 * we can put in some debugging.
 */
/*static HOOK_T ssl_read(void *cookie, char *buf, LEN_T len)
{
   int i = SSL_read(cookie, buf, len-1);
#if 0
   if (i >= 0)
      buf[i] = '\0';
   ast_verbose("ssl read size %d returns %d <%s>\n", (int)len, i, buf);
#endif
   return i;
}

static HOOK_T ssl_write(void *cookie, const char *buf, LEN_T len)
{
#if 0
   char *s = ast_alloca(len+1);
   strncpy(s, buf, len);
   s[len] = '\0';
   ast_verbose("ssl write size %d <%s>\n", (int)len, s);
#endif
   return SSL_write(cookie, buf, len);
}

static int ssl_close(void *cookie)
{
   close(SSL_get_fd(cookie));
   SSL_shutdown(cookie);
   SSL_free(cookie);
   return 0;
}*/
#endif   /* DO_SSL */

static struct ast_variable *parse_cookies(const char *cookies)
{
   char *parse = ast_strdupa(cookies);
   char *cur;
   struct ast_variable *vars = NULL, *var;

   while ((cur = strsep(&parse, ";"))) {
      char *name, *val;

      name = val = cur;
      strsep(&val, "=");

      if (ast_strlen_zero(name) || ast_strlen_zero(val)) {
         continue;
      }

      name = ast_strip(name);
      val = ast_strip_quoted(val, "\"", "\"");

      if (ast_strlen_zero(name) || ast_strlen_zero(val)) {
         continue;
      }

      ast_debug(1, "HTTP Cookie, Name: '%s'  Value: '%s'\n", name, val);

      var = ast_variable_new(name, val, __FILE__);
      var->next = vars;
      vars = var;
   }

   return vars;
}

/* get cookie from Request headers */
struct ast_variable *ast_http_get_cookies(struct ast_variable *headers)
{
   struct ast_variable *v, *cookies = NULL;

   for (v = headers; v; v = v->next) {
      if (!strcasecmp(v->name, "Cookie")) {
         ast_variables_destroy(cookies);
         cookies = parse_cookies(v->value);
      }
   }
   return cookies;
}

/*! Limit the number of request headers in case the sender is being ridiculous. */
#define MAX_HTTP_REQUEST_HEADERS 100

static void *httpd_helper_thread(void *data)
{
   char buf[4096];
   char header_line[4096];
   struct ast_tcptls_session_instance *ser = data;
   struct ast_variable *headers = NULL;
   struct ast_variable *tail = headers;
   char *uri, *method;
   enum ast_http_method http_method = AST_HTTP_UNKNOWN;
   int remaining_headers;

   if (ast_atomic_fetchadd_int(&session_count, +1) >= session_limit) {
      goto done;
   }

   if (!fgets(buf, sizeof(buf), ser->f)) {
      goto done;
   }

   /* Get method */
   method = ast_skip_blanks(buf);
   uri = ast_skip_nonblanks(method);
   if (*uri) {
      *uri++ = '\0';
   }

   if (!strcasecmp(method,"GET")) {
      http_method = AST_HTTP_GET;
   } else if (!strcasecmp(method,"POST")) {
      http_method = AST_HTTP_POST;
   } else if (!strcasecmp(method,"HEAD")) {
      http_method = AST_HTTP_HEAD;
   } else if (!strcasecmp(method,"PUT")) {
      http_method = AST_HTTP_PUT;
   }

   uri = ast_skip_blanks(uri);   /* Skip white space */

   if (*uri) {       /* terminate at the first blank */
      char *c = ast_skip_nonblanks(uri);

      if (*c) {
         *c = '\0';
      }
   } else {
      ast_http_error(ser, 400, "Bad Request", "Invalid Request");
      goto done;
   }

   /* process "Request Headers" lines */
   remaining_headers = MAX_HTTP_REQUEST_HEADERS;
   while (fgets(header_line, sizeof(header_line), ser->f)) {
      char *name, *value;

      /* Trim trailing characters */
      ast_trim_blanks(header_line);
      if (ast_strlen_zero(header_line)) {
         break;
      }

      value = header_line;
      name = strsep(&value, ":");
      if (!value) {
         continue;
      }

      value = ast_skip_blanks(value);
      if (ast_strlen_zero(value) || ast_strlen_zero(name)) {
         continue;
      }

      ast_trim_blanks(name);

      if (!remaining_headers--) {
         /* Too many headers. */
         ast_http_error(ser, 413, "Request Entity Too Large", "Too many headers");
         goto done;
      }
      if (!headers) {
         headers = ast_variable_new(name, value, __FILE__);
         tail = headers;
      } else {
         tail->next = ast_variable_new(name, value, __FILE__);
         tail = tail->next;
      }
      if (!tail) {
         /*
          * Variable allocation failure.
          * Try to make some room.
          */
         ast_variables_destroy(headers);
         headers = NULL;

         ast_http_error(ser, 500, "Server Error", "Out of memory");
         goto done;
      }
   }

   handle_uri(ser, uri, http_method, headers);

done:
   ast_atomic_fetchadd_int(&session_count, -1);

   /* clean up all the header information */
   ast_variables_destroy(headers);

   if (ser->f) {
      fclose(ser->f);
   }
   ao2_ref(ser, -1);
   ser = NULL;
   return NULL;
}

/*!
 * \brief Add a new URI redirect
 * The entries in the redirect list are sorted by length, just like the list
 * of URI handlers.
 */
static void add_redirect(const char *value)
{
   char *target, *dest;
   struct http_uri_redirect *redirect, *cur;
   unsigned int target_len;
   unsigned int total_len;

   dest = ast_strdupa(value);
   dest = ast_skip_blanks(dest);
   target = strsep(&dest, " ");
   target = ast_skip_blanks(target);
   target = strsep(&target, " "); /* trim trailing whitespace */

   if (!dest) {
      ast_log(LOG_WARNING, "Invalid redirect '%s'\n", value);
      return;
   }

   target_len = strlen(target) + 1;
   total_len = sizeof(*redirect) + target_len + strlen(dest) + 1;

   if (!(redirect = ast_calloc(1, total_len))) {
      return;
   }
   redirect->dest = redirect->target + target_len;
   strcpy(redirect->target, target);
   strcpy(redirect->dest, dest);

   AST_RWLIST_WRLOCK(&uri_redirects);

   target_len--; /* So we can compare directly with strlen() */
   if (AST_RWLIST_EMPTY(&uri_redirects)
      || strlen(AST_RWLIST_FIRST(&uri_redirects)->target) <= target_len ) {
      AST_RWLIST_INSERT_HEAD(&uri_redirects, redirect, entry);
      AST_RWLIST_UNLOCK(&uri_redirects);

      return;
   }

   AST_RWLIST_TRAVERSE(&uri_redirects, cur, entry) {
      if (AST_RWLIST_NEXT(cur, entry)
         && strlen(AST_RWLIST_NEXT(cur, entry)->target) <= target_len ) {
         AST_RWLIST_INSERT_AFTER(&uri_redirects, cur, redirect, entry);
         AST_RWLIST_UNLOCK(&uri_redirects);
         return;
      }
   }

   AST_RWLIST_INSERT_TAIL(&uri_redirects, redirect, entry);

   AST_RWLIST_UNLOCK(&uri_redirects);
}

static int __ast_http_load(int reload)
{
   struct ast_config *cfg;
   struct ast_variable *v;
   int enabled=0;
   int newenablestatic=0;
   struct hostent *hp;
   struct ast_hostent ahp;
   char newprefix[MAX_PREFIX] = "";
   struct http_uri_redirect *redirect;
   struct ast_flags config_flags = { reload ? CONFIG_FLAG_FILEUNCHANGED : 0 };
   struct sockaddr_in tmp = {0,};
   struct sockaddr_in tmp2 = {0,};
   int http_tls_was_enabled = 0;

   cfg = ast_config_load2("http.conf", "http", config_flags);
   if (cfg == CONFIG_STATUS_FILEMISSING || cfg == CONFIG_STATUS_FILEUNCHANGED || cfg == CONFIG_STATUS_FILEINVALID) {
      return 0;
   }

   http_tls_was_enabled = (reload && http_tls_cfg.enabled);

   tmp.sin_family = AF_INET;
   tmp.sin_port = htons(DEFAULT_HTTP_PORT);
   ast_sockaddr_from_sin(&http_desc.local_address, &tmp);

   http_tls_cfg.enabled = 0;
   if (http_tls_cfg.certfile) {
      ast_free(http_tls_cfg.certfile);
   }
   http_tls_cfg.certfile = ast_strdup(AST_CERTFILE);

   if (http_tls_cfg.pvtfile) {
      ast_free(http_tls_cfg.pvtfile);
   }
   http_tls_cfg.pvtfile = ast_strdup("");

   if (http_tls_cfg.cipher) {
      ast_free(http_tls_cfg.cipher);
   }
   http_tls_cfg.cipher = ast_strdup("");

   AST_RWLIST_WRLOCK(&uri_redirects);
   while ((redirect = AST_RWLIST_REMOVE_HEAD(&uri_redirects, entry))) {
      ast_free(redirect);
   }
   AST_RWLIST_UNLOCK(&uri_redirects);

   ast_sockaddr_setnull(&https_desc.local_address);

   if (cfg) {
      v = ast_variable_browse(cfg, "general");
      for (; v; v = v->next) {

         /* read tls config options while preventing unsupported options from being set */
         if (strcasecmp(v->name, "tlscafile")
            && strcasecmp(v->name, "tlscapath")
            && strcasecmp(v->name, "tlscadir")
            && strcasecmp(v->name, "tlsverifyclient")
            && strcasecmp(v->name, "tlsdontverifyserver")
            && strcasecmp(v->name, "tlsclientmethod")
            && strcasecmp(v->name, "sslclientmethod")
            && strcasecmp(v->name, "tlscipher")
            && strcasecmp(v->name, "sslcipher")
            && !ast_tls_read_conf(&http_tls_cfg, &https_desc, v->name, v->value)) {
            continue;
         }

         if (!strcasecmp(v->name, "enabled")) {
            enabled = ast_true(v->value);
         } else if (!strcasecmp(v->name, "enablestatic")) {
            newenablestatic = ast_true(v->value);
         } else if (!strcasecmp(v->name, "bindport")) {
            ast_sockaddr_set_port(&http_desc.local_address,
                        atoi(v->value));
         } else if (!strcasecmp(v->name, "bindaddr")) {
            if ((hp = ast_gethostbyname(v->value, &ahp))) {
               ast_sockaddr_to_sin(&http_desc.local_address,
                         &tmp);
               memcpy(&tmp.sin_addr, hp->h_addr, sizeof(tmp.sin_addr));
               ast_sockaddr_from_sin(&http_desc.local_address,
                           &tmp);
            } else {
               ast_log(LOG_WARNING, "Invalid bind address '%s'\n", v->value);
            }
         } else if (!strcasecmp(v->name, "prefix")) {
            if (!ast_strlen_zero(v->value)) {
               newprefix[0] = '/';
               ast_copy_string(newprefix + 1, v->value, sizeof(newprefix) - 1);
            } else {
               newprefix[0] = '\0';
            }
         } else if (!strcasecmp(v->name, "redirect")) {
            add_redirect(v->value);
         } else if (!strcasecmp(v->name, "sessionlimit")) {
            if (ast_parse_arg(v->value, PARSE_INT32|PARSE_DEFAULT|PARSE_IN_RANGE,
                     &session_limit, DEFAULT_SESSION_LIMIT, 1, INT_MAX)) {
               ast_log(LOG_WARNING, "Invalid %s '%s' at line %d of http.conf\n",
                     v->name, v->value, v->lineno);
            }
         } else {
            ast_log(LOG_WARNING, "Ignoring unknown option '%s' in http.conf\n", v->name);
         }
      }

      ast_config_destroy(cfg);
   }
   /* if the https address has not been set, default is the same as non secure http */
   ast_sockaddr_to_sin(&http_desc.local_address, &tmp);
   ast_sockaddr_to_sin(&https_desc.local_address, &tmp2);
   if (!tmp2.sin_addr.s_addr) {
      tmp2.sin_addr = tmp.sin_addr;
   }
   if (!tmp2.sin_port) {
      tmp2.sin_port = htons(DEFAULT_HTTPS_PORT);
   }
   ast_sockaddr_from_sin(&https_desc.local_address, &tmp2);
   if (!enabled) {
      ast_sockaddr_setnull(&http_desc.local_address);
      ast_sockaddr_setnull(&https_desc.local_address);
   }
   if (strcmp(prefix, newprefix)) {
      ast_copy_string(prefix, newprefix, sizeof(prefix));
   }
   enablestatic = newenablestatic;
   ast_tcptls_server_start(&http_desc);
   /* If https was enabled previously but now is not, then stop the service */
   if (http_tls_was_enabled && !http_tls_cfg.enabled) {
      ast_tcptls_server_stop(&https_desc);
   } else if (ast_ssl_setup(https_desc.tls_cfg)) {
      ast_tcptls_server_start(&https_desc);
   }

   return 0;
}

static char *handle_show_http(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct ast_http_uri *urih;
   struct http_uri_redirect *redirect;
   struct sockaddr_in tmp;

   switch (cmd) {
   case CLI_INIT:
      e->command = "http show status";
      e->usage =
         "Usage: http show status\n"
         "       Lists status of internal HTTP engine\n";
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   if (a->argc != 3) {
      return CLI_SHOWUSAGE;
   }
   ast_cli(a->fd, "HTTP Server Status:\n");
   ast_cli(a->fd, "Prefix: %s\n", prefix);
   ast_sockaddr_to_sin(&http_desc.old_address, &tmp);
   if (!tmp.sin_family) {
      ast_cli(a->fd, "Server Disabled\n\n");
   } else {
      ast_cli(a->fd, "Server Enabled and Bound to %s:%d\n\n",
         ast_inet_ntoa(tmp.sin_addr), ntohs(tmp.sin_port));
      if (http_tls_cfg.enabled) {
         ast_sockaddr_to_sin(&https_desc.old_address, &tmp);
         ast_cli(a->fd, "HTTPS Server Enabled and Bound to %s:%d\n\n",
            ast_inet_ntoa(tmp.sin_addr),
            ntohs(tmp.sin_port));
      }
   }

   ast_cli(a->fd, "Enabled URI's:\n");
   AST_RWLIST_RDLOCK(&uris);
   if (AST_RWLIST_EMPTY(&uris)) {
      ast_cli(a->fd, "None.\n");
   } else {
      AST_RWLIST_TRAVERSE(&uris, urih, entry)
         ast_cli(a->fd, "%s/%s%s => %s\n", prefix, urih->uri, (urih->has_subtree ? "/..." : "" ), urih->description);
   }
   AST_RWLIST_UNLOCK(&uris);

   ast_cli(a->fd, "\nEnabled Redirects:\n");
   AST_RWLIST_RDLOCK(&uri_redirects);
   AST_RWLIST_TRAVERSE(&uri_redirects, redirect, entry)
      ast_cli(a->fd, "  %s => %s\n", redirect->target, redirect->dest);
   if (AST_RWLIST_EMPTY(&uri_redirects)) {
      ast_cli(a->fd, "  None.\n");
   }
   AST_RWLIST_UNLOCK(&uri_redirects);

   return CLI_SUCCESS;
}

int ast_http_reload(void)
{
   return __ast_http_load(1);
}

static struct ast_cli_entry cli_http[] = {
   AST_CLI_DEFINE(handle_show_http, "Display HTTP server status"),
};

static void http_shutdown(void)
{
   struct http_uri_redirect *redirect;
   ast_cli_unregister_multiple(cli_http, ARRAY_LEN(cli_http));

   ast_tcptls_server_stop(&http_desc);
   if (http_tls_cfg.enabled) {
      ast_tcptls_server_stop(&https_desc);
   }
   ast_free(http_tls_cfg.certfile);
   ast_free(http_tls_cfg.pvtfile);
   ast_free(http_tls_cfg.cipher);

   ast_http_uri_unlink(&statusuri);
   ast_http_uri_unlink(&staticuri);

   AST_RWLIST_WRLOCK(&uri_redirects);
   while ((redirect = AST_RWLIST_REMOVE_HEAD(&uri_redirects, entry))) {
      ast_free(redirect);
   }
   AST_RWLIST_UNLOCK(&uri_redirects);
}

int ast_http_init(void)
{
   ast_http_uri_link(&statusuri);
   ast_http_uri_link(&staticuri);
   ast_cli_register_multiple(cli_http, ARRAY_LEN(cli_http));
   ast_register_atexit(http_shutdown);

   return __ast_http_load(0);
}