/*
 * Copyright (C) Yichun Zhang (agentzh)
 */


#ifndef DDEBUG
#define DDEBUG 0
#endif
#include "ddebug.h"


#if (NGX_HTTP_SSL)


#include "ngx_http_lua_cache.h"
#include "ngx_http_lua_initworkerby.h"
#include "ngx_http_lua_util.h"
#include "ngx_http_ssl_module.h"
#include "ngx_http_lua_contentby.h"
#include "ngx_http_lua_ssl_session_fetchby.h"
#include "ngx_http_lua_ssl.h"
#include "ngx_http_lua_directive.h"


/* Lua SSL cached session loading routines */
static void ngx_http_lua_ssl_sess_fetch_done(void *data);
static void ngx_http_lua_ssl_sess_fetch_aborted(void *data);
static u_char *ngx_http_lua_log_ssl_sess_fetch_error(ngx_log_t *log,
    u_char *buf, size_t len);
static ngx_int_t ngx_http_lua_ssl_sess_fetch_by_chunk(lua_State *L,
    ngx_http_request_t *r);


/* load Lua code from a file for fetching cached SSL session */
ngx_int_t
ngx_http_lua_ssl_sess_fetch_handler_file(ngx_http_request_t *r,
    ngx_http_lua_srv_conf_t *lscf, lua_State *L)
{
    ngx_int_t           rc;

    rc = ngx_http_lua_cache_loadfile(r->connection->log, L,
                                     lscf->srv.ssl_sess_fetch_src.data,
                                     lscf->srv.ssl_sess_fetch_src_key);
    if (rc != NGX_OK) {
        return rc;
    }

    /*  make sure we have a valid code chunk */
    ngx_http_lua_assert(lua_isfunction(L, -1));

    return ngx_http_lua_ssl_sess_fetch_by_chunk(L, r);
}


/* load lua code from an inline snippet for fetching cached SSL session */
ngx_int_t
ngx_http_lua_ssl_sess_fetch_handler_inline(ngx_http_request_t *r,
    ngx_http_lua_srv_conf_t *lscf, lua_State *L)
{
    ngx_int_t           rc;

    rc = ngx_http_lua_cache_loadbuffer(r->connection->log, L,
                                       lscf->srv.ssl_sess_fetch_src.data,
                                       lscf->srv.ssl_sess_fetch_src.len,
                                       lscf->srv.ssl_sess_fetch_src_key,
                                       "=ssl_session_fetch_by_lua_block");
    if (rc != NGX_OK) {
        return rc;
    }

    /*  make sure we have a valid code chunk */
    ngx_http_lua_assert(lua_isfunction(L, -1));

    return ngx_http_lua_ssl_sess_fetch_by_chunk(L, r);
}


char *
ngx_http_lua_ssl_sess_fetch_by_lua_block(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf)
{
    char        *rv;
    ngx_conf_t   save;

    save = *cf;
    cf->handler = ngx_http_lua_ssl_sess_fetch_by_lua;
    cf->handler_conf = conf;

    rv = ngx_http_lua_conf_lua_block_parse(cf, cmd);

    *cf = save;

    return rv;
}


/* conf parser for directive ssl_session_fetch_by_lua */
char *
ngx_http_lua_ssl_sess_fetch_by_lua(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf)
{
    u_char                      *p;
    u_char                      *name;
    ngx_str_t                   *value;
    ngx_http_lua_srv_conf_t     *lscf = conf;

    dd("enter");

    /*  must specifiy a content handler */
    if (cmd->post == NULL) {
        return NGX_CONF_ERROR;
    }

    if (lscf->srv.ssl_sess_fetch_handler) {
        return "is duplicate";
    }

    if (ngx_http_lua_ssl_init(cf->log) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    value = cf->args->elts;

    lscf->srv.ssl_sess_fetch_handler =
        (ngx_http_lua_srv_conf_handler_pt) cmd->post;

    if (cmd->post == ngx_http_lua_ssl_sess_fetch_handler_file) {
        /* Lua code in an external file */

        name = ngx_http_lua_rebase_path(cf->pool, value[1].data,
                                        value[1].len);
        if (name == NULL) {
            return NGX_CONF_ERROR;
        }

        lscf->srv.ssl_sess_fetch_src.data = name;
        lscf->srv.ssl_sess_fetch_src.len = ngx_strlen(name);

        p = ngx_palloc(cf->pool, NGX_HTTP_LUA_FILE_KEY_LEN + 1);
        if (p == NULL) {
            return NGX_CONF_ERROR;
        }

        lscf->srv.ssl_sess_fetch_src_key = p;

        p = ngx_copy(p, NGX_HTTP_LUA_FILE_TAG, NGX_HTTP_LUA_FILE_TAG_LEN);
        p = ngx_http_lua_digest_hex(p, value[1].data, value[1].len);
        *p = '\0';

    } else {
        /* inlined Lua code */

        lscf->srv.ssl_sess_fetch_src = value[1];

        p = ngx_palloc(cf->pool, NGX_HTTP_LUA_INLINE_KEY_LEN + 1);
        if (p == NULL) {
            return NGX_CONF_ERROR;
        }

        lscf->srv.ssl_sess_fetch_src_key = p;

        p = ngx_copy(p, NGX_HTTP_LUA_INLINE_TAG, NGX_HTTP_LUA_INLINE_TAG_LEN);
        p = ngx_http_lua_digest_hex(p, value[1].data, value[1].len);
        *p = '\0';
    }

    return NGX_CONF_OK;
}


/* cached session fetching callback to be set with SSL_CTX_sess_set_get_cb */
ngx_ssl_session_t *
ngx_http_lua_ssl_sess_fetch_handler(ngx_ssl_conn_t *ssl_conn, u_char *id,
    int len, int *copy)
{
    lua_State                       *L;
    ngx_int_t                        rc;
    ngx_connection_t                *c, *fc = NULL;
    ngx_http_request_t              *r = NULL;
    ngx_pool_cleanup_t              *cln;
    ngx_http_connection_t           *hc;
    ngx_http_lua_ssl_ctx_t          *cctx;
    ngx_http_lua_srv_conf_t         *lscf;
    ngx_http_core_loc_conf_t        *clcf;

    /* set copy to 0 as we expect OpenSSL to handle
     * the memory of returned session */

    *copy = 0;

    c = ngx_ssl_get_connection(ssl_conn);

    dd("c = %p", c);

    cctx = ngx_http_lua_ssl_get_ctx(c->ssl->connection);

    dd("ssl sess_fetch handler, sess_fetch-ctx=%p", cctx);

    if (cctx && cctx->entered_sess_fetch_handler) {
        /* not the first time */

        dd("here: %d", (int) cctx->entered_sess_fetch_handler);

        if (cctx->done) {
            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                           "ssl_session_fetch_by_lua*: "
                           "sess get cb exit code: %d",
                           cctx->exit_code);

            dd("lua ssl sess_fetch done, finally");
            return cctx->session;
        }

#ifdef SSL_ERROR_PENDING_SESSION
        return SSL_magic_pending_session_ptr();
#else
        ngx_log_error(NGX_LOG_CRIT, c->log, 0,
                      "lua: cannot yield in sess get cb: "
                      "missing async sess get cb support in OpenSSL");
        return NULL;
#endif
    }

    dd("first time");

    hc = c->data;

    fc = ngx_http_lua_create_fake_connection(NULL);
    if (fc == NULL) {
        goto failed;
    }

    fc->log->handler = ngx_http_lua_log_ssl_sess_fetch_error;
    fc->log->data = fc;

    fc->addr_text = c->addr_text;
    fc->listening = c->listening;

    r = ngx_http_lua_create_fake_request(fc);
    if (r == NULL) {
        goto failed;
    }

    r->main_conf = hc->conf_ctx->main_conf;
    r->srv_conf = hc->conf_ctx->srv_conf;
    r->loc_conf = hc->conf_ctx->loc_conf;

    fc->log->file = c->log->file;
    fc->log->log_level = c->log->log_level;
    fc->ssl = c->ssl;

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

#if defined(nginx_version) && nginx_version >= 1003014

#   if nginx_version >= 1009000

    ngx_set_connection_log(fc, clcf->error_log);

#   else

    ngx_http_set_connection_log(fc, clcf->error_log);

#   endif

#else

    fc->log->file = clcf->error_log->file;

    if (!(fc->log->log_level & NGX_LOG_DEBUG_CONNECTION)) {
        fc->log->log_level = clcf->error_log->log_level;
    }

#endif

    if (cctx == NULL) {
        cctx = ngx_pcalloc(c->pool, sizeof(ngx_http_lua_ssl_ctx_t));
        if (cctx == NULL) {
            goto failed;  /* error */
        }
    }

    cctx->exit_code = 1;  /* successful by default */
    cctx->connection = c;
    cctx->request = r;
    cctx->session_id.data = id;
    cctx->session_id.len = len;
    cctx->entered_sess_fetch_handler = 1;
    cctx->done = 0;

    dd("setting cctx = %p", cctx);

    if (SSL_set_ex_data(c->ssl->connection, ngx_http_lua_ssl_ctx_index, cctx)
        == 0)
    {
        ngx_ssl_error(NGX_LOG_ALERT, c->log, 0, "SSL_set_ex_data() failed");
        goto failed;
    }

    lscf = ngx_http_get_module_srv_conf(r, ngx_http_lua_module);

    /* TODO honor lua_code_cache off */
    L = ngx_http_lua_get_lua_vm(r, NULL);

    c->log->action = "fetching SSL session by lua";

    rc = lscf->srv.ssl_sess_fetch_handler(r, lscf, L);

    if (rc >= NGX_OK || rc == NGX_ERROR) {
        cctx->done = 1;

        if (cctx->cleanup) {
            *cctx->cleanup = NULL;
        }

        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                       "ssl_session_fetch_by_lua*: handler return value: %i, "
                       "sess get cb exit code: %d", rc, cctx->exit_code);

        c->log->action = "SSL handshaking";
        return cctx->session;
    }

    /* rc == NGX_DONE */

    cln = ngx_pool_cleanup_add(fc->pool, 0);
    if (cln == NULL) {
        goto failed;
    }

    cln->handler = ngx_http_lua_ssl_sess_fetch_done;
    cln->data = cctx;

    if (cctx->cleanup == NULL)  {
        /* we only want exactly one cleanup handler to be registered with the
         * connection to clean up cctx when connection is aborted */
        cln = ngx_pool_cleanup_add(c->pool, 0);
        if (cln == NULL) {
            goto failed;
        }

        cln->data = cctx;
        cctx->cleanup = &cln->handler;
    }

    *cctx->cleanup = ngx_http_lua_ssl_sess_fetch_aborted;

#ifdef SSL_ERROR_PENDING_SESSION
    return SSL_magic_pending_session_ptr();
#else
    ngx_log_error(NGX_LOG_CRIT, c->log, 0,
                  "lua: cannot yield in sess get cb: "
                  "missing async sess get cb support in OpenSSL");

    /* fall through to the "failed" label below */
#endif

failed:

    if (r && r->pool) {
        ngx_http_lua_free_fake_request(r);
    }

    if (fc) {
        ngx_http_lua_close_fake_connection(fc);
    }

    return NULL;
}


static void
ngx_http_lua_ssl_sess_fetch_done(void *data)
{
    ngx_connection_t                *c;
    ngx_http_lua_ssl_ctx_t          *cctx = data;

    dd("lua ssl sess_fetch done");

    if (cctx->aborted) {
        return;
    }

    ngx_http_lua_assert(cctx->done == 0);

    cctx->done = 1;

    if (cctx->cleanup) {
        *cctx->cleanup = NULL;
    }

    c = cctx->connection;

    c->log->action = "SSL handshaking";

    ngx_post_event(c->write, &ngx_posted_events);
}


static void
ngx_http_lua_ssl_sess_fetch_aborted(void *data)
{
    ngx_http_lua_ssl_ctx_t          *cctx = data;

    dd("lua ssl sess_fetch done");

    if (cctx->done) {
        /* completed successfully already */
        return;
    }

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, cctx->connection->log, 0,
                   "ssl_session_fetch_by_lua*: sess_fetch cb aborted");

    cctx->aborted = 1;
    cctx->request->connection->ssl = NULL;

    ngx_http_lua_finalize_fake_request(cctx->request, NGX_ERROR);
}


static u_char *
ngx_http_lua_log_ssl_sess_fetch_error(ngx_log_t *log, u_char *buf, size_t len)
{
    u_char              *p;
    ngx_connection_t    *c;

    if (log->action) {
        p = ngx_snprintf(buf, len, " while %s", log->action);
        len -= p - buf;
        buf = p;
    }

    p = ngx_snprintf(buf, len, ", context: ssl_session_fetch_by_lua*");
    len -= p - buf;
    buf = p;

    c = log->data;

    if (c->addr_text.len) {
        p = ngx_snprintf(buf, len, ", client: %V", &c->addr_text);
        len -= p - buf;
        buf = p;
    }

    if (c && c->listening && c->listening->addr_text.len) {
        p = ngx_snprintf(buf, len, ", server: %V", &c->listening->addr_text);
        buf = p;
    }

    return buf;
}


/* initialize lua coroutine for fetching cached session */
static ngx_int_t
ngx_http_lua_ssl_sess_fetch_by_chunk(lua_State *L, ngx_http_request_t *r)
{
    int                      co_ref;
    ngx_int_t                rc;
    lua_State               *co;
    ngx_http_lua_ctx_t      *ctx;
    ngx_http_cleanup_t      *cln;

    ctx = ngx_http_get_module_ctx(r, ngx_http_lua_module);

    if (ctx == NULL) {
        ctx = ngx_http_lua_create_ctx(r);
        if (ctx == NULL) {
            return NGX_HTTP_INTERNAL_SERVER_ERROR;
        }

    } else {
        dd("reset ctx");
        ngx_http_lua_reset_ctx(r, L, ctx);
    }

    ctx->entered_content_phase = 1;

    /*  {{{ new coroutine to handle request */
    co = ngx_http_lua_new_thread(r, L, &co_ref);

    if (co == NULL) {
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "lua: failed to create new coroutine to handle request");

        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    /*  move code closure to new coroutine */
    lua_xmove(L, co, 1);

    /*  set closure's env table to new coroutine's globals table */
    ngx_http_lua_get_globals_table(co);
    lua_setfenv(co, -2);

    /* save nginx request in coroutine globals table */
    ngx_http_lua_set_req(co, r);

    ctx->cur_co_ctx = &ctx->entry_co_ctx;
    ctx->cur_co_ctx->co = co;
    ctx->cur_co_ctx->co_ref = co_ref;
#ifdef NGX_LUA_USE_ASSERT
    ctx->cur_co_ctx->co_top = 1;
#endif

    /* register request cleanup hooks */
    if (ctx->cleanup == NULL) {
        cln = ngx_http_cleanup_add(r, 0);
        if (cln == NULL) {
            return NGX_HTTP_INTERNAL_SERVER_ERROR;
        }

        cln->handler = ngx_http_lua_request_cleanup_handler;
        cln->data = ctx;
        ctx->cleanup = &cln->handler;
    }

    ctx->context = NGX_HTTP_LUA_CONTEXT_SSL_SESS_FETCH;

    rc = ngx_http_lua_run_thread(L, r, ctx, 0);

    if (rc == NGX_ERROR || rc >= NGX_OK) {
        /* do nothing */

    } else if (rc == NGX_AGAIN) {
        rc = ngx_http_lua_content_run_posted_threads(L, r, ctx, 0);

    } else if (rc == NGX_DONE) {
        rc = ngx_http_lua_content_run_posted_threads(L, r, ctx, 1);

    } else {
        rc = NGX_OK;
    }

    ngx_http_lua_finalize_request(r, rc);
    return rc;
}


#ifndef NGX_LUA_NO_FFI_API

/* de-serialized a SSL session and set it back to the request at lua context */
int
ngx_http_lua_ffi_ssl_set_serialized_session(ngx_http_request_t *r,
    const unsigned char *data, int len, char **err)
{
    u_char                          *p;
    u_char                           buf[NGX_SSL_MAX_SESSION_SIZE];
    ngx_ssl_conn_t                  *ssl_conn;
    ngx_connection_t                *c;
    ngx_ssl_session_t               *session = NULL;
    ngx_http_lua_ssl_ctx_t          *cctx;

    c = r->connection;

    if (c == NULL || c->ssl == NULL) {
        *err = "bad request";
        return NGX_ERROR;
    }

    ssl_conn = c->ssl->connection;
    if (ssl_conn == NULL) {
        *err = "bad ssl conn";
        return NGX_ERROR;
    }

    ngx_memcpy(buf, data, len);
    p = buf;
    session = d2i_SSL_SESSION(NULL, (const unsigned char **)&p,  len);
    if (session == NULL) {
        ERR_clear_error();
        *err = "failed to de-serialize session";
        return NGX_ERROR;
    }

    cctx = ngx_http_lua_ssl_get_ctx(c->ssl->connection);
    if (cctx == NULL) {
        *err = "bad lua context";
        return NGX_ERROR;
    }

    cctx->session = session;

    return NGX_OK;
}

#endif  /* NGX_LUA_NO_FFI_API */


#endif /* NGX_HTTP_SSL */