/*
  * TLS/SSL Protocol
  * Copyright (c) 2011 Martin Storsjo
  *

  * This file is part of FFmpeg.

  *

  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *

  * FFmpeg is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include "avformat.h"
 #include "url.h"
 #include "libavutil/avstring.h"

 #include "libavutil/opt.h"

 #include "libavutil/parseutils.h"

 #include "network.h"
 #include "os_support.h"
 #include "internal.h"

 #if CONFIG_GNUTLS
 #include <gnutls/gnutls.h>

 #include <gnutls/x509.h>

 #define TLS_read(c, buf, size)  gnutls_record_recv(c->session, buf, size)
 #define TLS_write(c, buf, size) gnutls_record_send(c->session, buf, size)
 #define TLS_shutdown(c)         gnutls_bye(c->session, GNUTLS_SHUT_RDWR)
 #define TLS_free(c) do { \
         if (c->session) \
             gnutls_deinit(c->session); \
         if (c->cred) \
             gnutls_certificate_free_credentials(c->cred); \
     } while (0)
 #elif CONFIG_OPENSSL
 #include <openssl/bio.h>
 #include <openssl/ssl.h>
 #include <openssl/err.h>
 #define TLS_read(c, buf, size)  SSL_read(c->ssl,  buf, size)
 #define TLS_write(c, buf, size) SSL_write(c->ssl, buf, size)
 #define TLS_shutdown(c)         SSL_shutdown(c->ssl)
 #define TLS_free(c) do { \
         if (c->ssl) \
             SSL_free(c->ssl); \
         if (c->ctx) \
             SSL_CTX_free(c->ctx); \
     } while (0)
 #endif
 #if HAVE_POLL_H
 #include <poll.h>
 #endif
 
 typedef struct {
     const AVClass *class;
     URLContext *tcp;
 #if CONFIG_GNUTLS
     gnutls_session_t session;
     gnutls_certificate_credentials_t cred;
 #elif CONFIG_OPENSSL
     SSL_CTX *ctx;
     SSL *ssl;
 #endif
     int fd;

     char *ca_file;
     int verify;

     char *cert_file;
     char *key_file;
     int listen;

 } TLSContext;
 

 #define OFFSET(x) offsetof(TLSContext, x)
 #define D AV_OPT_FLAG_DECODING_PARAM
 #define E AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {
     {"ca_file",    "Certificate Authority database file", OFFSET(ca_file),   AV_OPT_TYPE_STRING, .flags = D|E },

     {"cafile",     "Certificate Authority database file", OFFSET(ca_file),   AV_OPT_TYPE_STRING, .flags = D|E },

     {"tls_verify", "Verify the peer certificate",         OFFSET(verify),    AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, .flags = D|E },

     {"cert_file",  "Certificate file",                    OFFSET(cert_file), AV_OPT_TYPE_STRING, .flags = D|E },
     {"key_file",   "Private key file",                    OFFSET(key_file),  AV_OPT_TYPE_STRING, .flags = D|E },
     {"listen",     "Listen for incoming connections",     OFFSET(listen),    AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, .flags = D|E },

     { NULL }
 };
 
 static const AVClass tls_class = {
     .class_name = "tls",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 static int do_tls_poll(URLContext *h, int ret)
 {
     TLSContext *c = h->priv_data;
     struct pollfd p = { c->fd, 0, 0 };
 #if CONFIG_GNUTLS

     switch (ret) {
     case GNUTLS_E_AGAIN:
     case GNUTLS_E_INTERRUPTED:
         break;
     case GNUTLS_E_WARNING_ALERT_RECEIVED:
         av_log(h, AV_LOG_WARNING, "%s\n", gnutls_strerror(ret));
         break;
     default:

         av_log(h, AV_LOG_ERROR, "%s\n", gnutls_strerror(ret));

         return AVERROR(EIO);
     }
     if (gnutls_record_get_direction(c->session))
         p.events = POLLOUT;
     else
         p.events = POLLIN;
 #elif CONFIG_OPENSSL
     ret = SSL_get_error(c->ssl, ret);
     if (ret == SSL_ERROR_WANT_READ) {
         p.events = POLLIN;
     } else if (ret == SSL_ERROR_WANT_WRITE) {
         p.events = POLLOUT;
     } else {

         av_log(h, AV_LOG_ERROR, "%s\n", ERR_error_string(ERR_get_error(), NULL));

         return AVERROR(EIO);
     }
 #endif

     if (h->flags & AVIO_FLAG_NONBLOCK)

         return AVERROR(EAGAIN);
     while (1) {
         int n = poll(&p, 1, 100);
         if (n > 0)
             break;

         if (ff_check_interrupt(&h->interrupt_callback))

             return AVERROR(EINTR);
     }
     return 0;
 }
 

 static void set_options(URLContext *h, const char *uri)
 {
     TLSContext *c = h->priv_data;

     char buf[1024];

     const char *p = strchr(uri, '?');
     if (!p)
         return;
 

     if (!c->ca_file && av_find_info_tag(buf, sizeof(buf), "cafile", p))
         c->ca_file = av_strdup(buf);

     if (!c->verify && av_find_info_tag(buf, sizeof(buf), "verify", p)) {

         char *endptr = NULL;

         c->verify = strtol(buf, &endptr, 10);

         if (buf == endptr)

             c->verify = 1;

     }
 

     if (!c->cert_file && av_find_info_tag(buf, sizeof(buf), "cert", p))
         c->cert_file = av_strdup(buf);
 
     if (!c->key_file && av_find_info_tag(buf, sizeof(buf), "key", p))
         c->key_file = av_strdup(buf);

 }
 

 static int tls_open(URLContext *h, const char *uri, int flags)
 {
     TLSContext *c = h->priv_data;
     int ret;
     int port;

     char buf[200], host[200], opts[50] = "";

     int numerichost = 0;
     struct addrinfo hints = { 0 }, *ai = NULL;

     const char *proxy_path;
     int use_proxy;

     const char *p = strchr(uri, '?');

 
     ff_tls_init();
 

     if(p && av_find_info_tag(buf, sizeof(buf), "listen", p))
         c->listen = 1;

     if (c->listen)
         snprintf(opts, sizeof(opts), "?listen=1");
 

     av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port, NULL, 0, uri);

     ff_url_join(buf, sizeof(buf), "tcp", NULL, host, port, "%s", opts);

 
     hints.ai_flags = AI_NUMERICHOST;
     if (!getaddrinfo(host, NULL, &hints, &ai)) {
         numerichost = 1;
         freeaddrinfo(ai);
     }
 

     proxy_path = getenv("http_proxy");
     use_proxy = !ff_http_match_no_proxy(getenv("no_proxy"), host) &&
                 proxy_path != NULL && av_strstart(proxy_path, "http://", NULL);
 

     if (use_proxy) {
         char proxy_host[200], proxy_auth[200], dest[200];
         int proxy_port;
         av_url_split(NULL, 0, proxy_auth, sizeof(proxy_auth),
                      proxy_host, sizeof(proxy_host), &proxy_port, NULL, 0,
                      proxy_path);
         ff_url_join(dest, sizeof(dest), NULL, NULL, host, port, NULL);
         ff_url_join(buf, sizeof(buf), "httpproxy", proxy_auth, proxy_host,
                     proxy_port, "/%s", dest);
     }
 

     ret = ffurl_open(&c->tcp, buf, AVIO_FLAG_READ_WRITE,
                      &h->interrupt_callback, NULL);

     if (ret)
         goto fail;
     c->fd = ffurl_get_file_handle(c->tcp);
 
 #if CONFIG_GNUTLS

     gnutls_init(&c->session, c->listen ? GNUTLS_SERVER : GNUTLS_CLIENT);
     if (!c->listen && !numerichost)

         gnutls_server_name_set(c->session, GNUTLS_NAME_DNS, host, strlen(host));
     gnutls_certificate_allocate_credentials(&c->cred);

     set_options(h, uri);

     if (c->ca_file) {
         ret = gnutls_certificate_set_x509_trust_file(c->cred, c->ca_file, GNUTLS_X509_FMT_PEM);
         if (ret < 0)
             av_log(h, AV_LOG_ERROR, "%s\n", gnutls_strerror(ret));
     }

 #if GNUTLS_VERSION_MAJOR >= 3
     else
         gnutls_certificate_set_x509_system_trust(c->cred);
 #endif
     gnutls_certificate_set_verify_flags(c->cred, c->verify ?
                                         GNUTLS_VERIFY_ALLOW_X509_V1_CA_CRT : 0);

     if (c->cert_file && c->key_file) {
         ret = gnutls_certificate_set_x509_key_file(c->cred,
                                                    c->cert_file, c->key_file,
                                                    GNUTLS_X509_FMT_PEM);
         if (ret < 0) {
             av_log(h, AV_LOG_ERROR,
                    "Unable to set cert/key files %s and %s: %s\n",
                    c->cert_file, c->key_file, gnutls_strerror(ret));
             ret = AVERROR(EIO);
             goto fail;
         }

     } else if (c->cert_file || c->key_file)

         av_log(h, AV_LOG_ERROR, "cert and key required\n");

     gnutls_credentials_set(c->session, GNUTLS_CRD_CERTIFICATE, c->cred);
     gnutls_transport_set_ptr(c->session, (gnutls_transport_ptr_t)
                                          (intptr_t) c->fd);
     gnutls_priority_set_direct(c->session, "NORMAL", NULL);
     while (1) {
         ret = gnutls_handshake(c->session);
         if (ret == 0)
             break;
         if ((ret = do_tls_poll(h, ret)) < 0)
             goto fail;
     }

     if (c->verify) {
         unsigned int status, cert_list_size;
         gnutls_x509_crt_t cert;
         const gnutls_datum_t *cert_list;
         if ((ret = gnutls_certificate_verify_peers2(c->session, &status)) < 0) {
             av_log(h, AV_LOG_ERROR, "Unable to verify peer certificate: %s\n",
                                     gnutls_strerror(ret));
             ret = AVERROR(EIO);
             goto fail;
         }
         if (status & GNUTLS_CERT_INVALID) {
             av_log(h, AV_LOG_ERROR, "Peer certificate failed verification\n");
             ret = AVERROR(EIO);
             goto fail;
         }
         if (gnutls_certificate_type_get(c->session) != GNUTLS_CRT_X509) {
             av_log(h, AV_LOG_ERROR, "Unsupported certificate type\n");
             ret = AVERROR(EIO);
             goto fail;
         }
         gnutls_x509_crt_init(&cert);
         cert_list = gnutls_certificate_get_peers(c->session, &cert_list_size);
         gnutls_x509_crt_import(cert, cert_list, GNUTLS_X509_FMT_DER);
         ret = gnutls_x509_crt_check_hostname(cert, host);
         gnutls_x509_crt_deinit(cert);
         if (!ret) {
             av_log(h, AV_LOG_ERROR,
                    "The certificate's owner does not match hostname %s\n", host);
             ret = AVERROR(EIO);
             goto fail;
         }
     }

 #elif CONFIG_OPENSSL

     c->ctx = SSL_CTX_new(c->listen ? TLSv1_server_method() : TLSv1_client_method());

     if (!c->ctx) {

         av_log(h, AV_LOG_ERROR, "%s\n", ERR_error_string(ERR_get_error(), NULL));

         ret = AVERROR(EIO);
         goto fail;
     }

     set_options(h, uri);

     if (c->ca_file) {
         if (!SSL_CTX_load_verify_locations(c->ctx, c->ca_file, NULL))
             av_log(h, AV_LOG_ERROR, "SSL_CTX_load_verify_locations %s\n", ERR_error_string(ERR_get_error(), NULL));
     }

     if (c->cert_file && !SSL_CTX_use_certificate_chain_file(c->ctx, c->cert_file)) {
         av_log(h, AV_LOG_ERROR, "Unable to load cert file %s: %s\n",
                c->cert_file, ERR_error_string(ERR_get_error(), NULL));
         ret = AVERROR(EIO);
         goto fail;
     }
     if (c->key_file && !SSL_CTX_use_PrivateKey_file(c->ctx, c->key_file, SSL_FILETYPE_PEM)) {
         av_log(h, AV_LOG_ERROR, "Unable to load key file %s: %s\n",
                c->key_file, ERR_error_string(ERR_get_error(), NULL));
         ret = AVERROR(EIO);
         goto fail;
     }

     // Note, this doesn't check that the peer certificate actually matches
     // the requested hostname.
     if (c->verify)

         SSL_CTX_set_verify(c->ctx, SSL_VERIFY_PEER|SSL_VERIFY_FAIL_IF_NO_PEER_CERT, NULL);

     c->ssl = SSL_new(c->ctx);
     if (!c->ssl) {

         av_log(h, AV_LOG_ERROR, "%s\n", ERR_error_string(ERR_get_error(), NULL));

         ret = AVERROR(EIO);
         goto fail;
     }
     SSL_set_fd(c->ssl, c->fd);

     if (!c->listen && !numerichost)

         SSL_set_tlsext_host_name(c->ssl, host);
     while (1) {

         ret = c->listen ? SSL_accept(c->ssl) : SSL_connect(c->ssl);

         if (ret > 0)
             break;
         if (ret == 0) {

             av_log(h, AV_LOG_ERROR, "Unable to negotiate TLS/SSL session\n");

             ret = AVERROR(EIO);
             goto fail;
         }
         if ((ret = do_tls_poll(h, ret)) < 0)
             goto fail;
     }
 #endif
     return 0;
 fail:
     TLS_free(c);
     if (c->tcp)
         ffurl_close(c->tcp);
     ff_tls_deinit();
     return ret;
 }
 
 static int tls_read(URLContext *h, uint8_t *buf, int size)
 {
     TLSContext *c = h->priv_data;
     while (1) {
         int ret = TLS_read(c, buf, size);
         if (ret > 0)
             return ret;
         if (ret == 0)

             return AVERROR_EOF;

         if ((ret = do_tls_poll(h, ret)) < 0)
             return ret;
     }
     return 0;
 }
 
 static int tls_write(URLContext *h, const uint8_t *buf, int size)
 {
     TLSContext *c = h->priv_data;
     while (1) {
         int ret = TLS_write(c, buf, size);
         if (ret > 0)
             return ret;
         if (ret == 0)

             return AVERROR_EOF;

         if ((ret = do_tls_poll(h, ret)) < 0)
             return ret;
     }
     return 0;
 }
 
 static int tls_close(URLContext *h)
 {
     TLSContext *c = h->priv_data;
     TLS_shutdown(c);
     TLS_free(c);
     ffurl_close(c->tcp);
     ff_tls_deinit();
     return 0;
 }
 
 URLProtocol ff_tls_protocol = {
     .name           = "tls",
     .url_open       = tls_open,
     .url_read       = tls_read,
     .url_write      = tls_write,
     .url_close      = tls_close,
     .priv_data_size = sizeof(TLSContext),

     .flags          = URL_PROTOCOL_FLAG_NETWORK,

     .priv_data_class = &tls_class,

 };