avformat/gopher: Add support for Gopher over TLS

This commit adds a "gophers" handler to the gopher protocol. gophers
is a community-adopted protocol that acts the same way like normal
gopher with the added TLS encapsulation.

The gophers protocol is supported by gopher servers like geomydae(8),
and clients like curl(1), clic(1), and hurl(1).

This commit also adds compilation guards to both gopher and gophers,
since now there are two protocols in the file it makes sense to
have this addition.

Signed-off-by: parazyd <parazyd@dyne.org>
Signed-off-by: Marton Balint <cus@passwd.hu>

Changelog

@@ -81,6 +81,7 @@ version <next>:
 - TTML subtitle encoder and muxer
 - identity video filter
 - msad video filter
+- gophers protocol
 
 
 version 4.3:

configure

@@ -3450,6 +3450,7 @@ ffrtmphttp_protocol_conflict="librtmp_protocol"
 ffrtmphttp_protocol_select="http_protocol"
 ftp_protocol_select="tcp_protocol"
 gopher_protocol_select="tcp_protocol"
+gophers_protocol_select="tls_protocol"
 http_protocol_select="tcp_protocol"
 http_protocol_suggest="zlib"
 httpproxy_protocol_select="tcp_protocol"

doc/general_contents.texi

@@ -1371,6 +1371,7 @@ performance on systems without hardware floating point support).
 @item file         @tab X
 @item FTP          @tab X
 @item Gopher       @tab X
+@item Gophers      @tab X
 @item HLS          @tab X
 @item HTTP         @tab X
 @item HTTPS        @tab X

doc/protocols.texi

@@ -341,6 +341,12 @@ operation. ff* tools may produce incomplete content due to server limitations.
 
 Gopher protocol.
 
+@section gophers
+
+Gophers protocol.
+
+The Gopher protocol with TLS encapsulation.
+
 @section hls
 
 Read Apple HTTP Live Streaming compliant segmented stream as

libavformat/Makefile

@@ -621,6 +621,7 @@ OBJS-$(CONFIG_FFRTMPHTTP_PROTOCOL)       += rtmphttp.o
 OBJS-$(CONFIG_FILE_PROTOCOL)             += file.o
 OBJS-$(CONFIG_FTP_PROTOCOL)              += ftp.o urldecode.o
 OBJS-$(CONFIG_GOPHER_PROTOCOL)           += gopher.o
+OBJS-$(CONFIG_GOPHERS_PROTOCOL)          += gopher.o
 OBJS-$(CONFIG_HLS_PROTOCOL)              += hlsproto.o
 OBJS-$(CONFIG_HTTP_PROTOCOL)             += http.o httpauth.o urldecode.o
 OBJS-$(CONFIG_HTTPPROXY_PROTOCOL)        += http.o httpauth.o urldecode.o

libavformat/gopher.c

@@ -2,6 +2,7 @@
  * Gopher protocol
  *
  * Copyright (c) 2009 Toshimitsu Kimura
+ * Copyright (c) 2021 parazyd <parazyd@dyne.org>
  *
  * based on libavformat/http.c, Copyright (c) 2000, 2001 Fabrice Bellard
  *
@@ -22,6 +23,8 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include "config.h"
+
 #include "libavutil/avstring.h"
 #include "avformat.h"
 #include "internal.h"
@@ -75,19 +78,23 @@ static int gopher_close(URLContext *h)
 static int gopher_open(URLContext *h, const char *uri, int flags)
 {
     GopherContext *s = h->priv_data;
-    char hostname[1024], auth[1024], path[1024], buf[1024];
+    char proto[10], hostname[1024], auth[1024], path[1024], buf[1024];
     int port, err;
+    const char *lower_proto = "tcp";
 
     h->is_streamed = 1;
 
     /* needed in any case to build the host string */
-    av_url_split(NULL, 0, auth, sizeof(auth), hostname, sizeof(hostname), &port,
-                 path, sizeof(path), uri);
+    av_url_split(proto, sizeof(proto), auth, sizeof(auth),
+                 hostname, sizeof(hostname), &port, path, sizeof(path), uri);
 
     if (port < 0)
         port = 70;
 
-    ff_url_join(buf, sizeof(buf), "tcp", NULL, hostname, port, NULL);
+    if (!strcmp(proto, "gophers"))
+        lower_proto = "tls";
+
+    ff_url_join(buf, sizeof(buf), lower_proto, NULL, hostname, port, NULL);
 
     s->hd = NULL;
     err = ffurl_open_whitelist(&s->hd, buf, AVIO_FLAG_READ_WRITE,
@@ -110,6 +117,7 @@ static int gopher_read(URLContext *h, uint8_t *buf, int size)
     return len;
 }
 
+#if CONFIG_GOPHER_PROTOCOL
 const URLProtocol ff_gopher_protocol = {
     .name              = "gopher",
     .url_open          = gopher_open,
@@ -120,3 +128,17 @@ const URLProtocol ff_gopher_protocol = {
     .flags             = URL_PROTOCOL_FLAG_NETWORK,
     .default_whitelist = "gopher,tcp"
 };
+#endif /* CONFIG_GOPHER_PROTOCOL */
+
+#if CONFIG_GOPHERS_PROTOCOL
+const URLProtocol ff_gophers_protocol = {
+    .name              = "gophers",
+    .url_open          = gopher_open,
+    .url_read          = gopher_read,
+    .url_write         = gopher_write,
+    .url_close         = gopher_close,
+    .priv_data_size    = sizeof(GopherContext),
+    .flags             = URL_PROTOCOL_FLAG_NETWORK,
+    .default_whitelist = "gopher,gophers,tcp,tls"
+};
+#endif /* CONFIG_GOPHERS_PROTOCOL */

libavformat/protocols.c

@@ -34,6 +34,7 @@ extern const URLProtocol ff_ffrtmphttp_protocol;
 extern const URLProtocol ff_file_protocol;
 extern const URLProtocol ff_ftp_protocol;
 extern const URLProtocol ff_gopher_protocol;
+extern const URLProtocol ff_gophers_protocol;
 extern const URLProtocol ff_hls_protocol;
 extern const URLProtocol ff_http_protocol;
 extern const URLProtocol ff_httpproxy_protocol;

libavformat/version.h

@@ -32,7 +32,7 @@
 // Major bumping may affect Ticket5467, 5421, 5451(compatibility with Chromium)
 // Also please add any ticket numbers that you believe might be affected here
 #define LIBAVFORMAT_VERSION_MAJOR  58
-#define LIBAVFORMAT_VERSION_MINOR  72
+#define LIBAVFORMAT_VERSION_MINOR  73
 #define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \