[FFmpeg-cvslog] lavf: Add a protocol for SRTP encryption/decryption

Martin Storsjö git at videolan.org
Tue Jan 15 16:12:14 CET 2013


ffmpeg | branch: master | Martin Storsjö <martin at martin.st> | Wed Dec 12 00:22:48 2012 +0200| [2f3bada63e57345329c4f9b48e9b81b5cfc03d05] | committer: Martin Storsjö

lavf: Add a protocol for SRTP encryption/decryption

This is mostly useful for encryption together with the RTP muxer,
but could also be set up as IO towards the peer with the SDP
demuxer with custom IO.

Signed-off-by: Martin Storsjö <martin at martin.st>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=2f3bada63e57345329c4f9b48e9b81b5cfc03d05
---

 libavformat/Makefile     |    1 +
 libavformat/allformats.c |    1 +
 libavformat/srtpproto.c  |  144 ++++++++++++++++++++++++++++++++++++++++++++++
 libavformat/version.h    |    4 +-
 4 files changed, 148 insertions(+), 2 deletions(-)

diff --git a/libavformat/Makefile b/libavformat/Makefile
index 7c0b926..1f008a9 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -367,6 +367,7 @@ OBJS-$(CONFIG_RTMPTE_PROTOCOL)           += rtmpproto.o rtmppkt.o
 OBJS-$(CONFIG_RTMPTS_PROTOCOL)           += rtmpproto.o rtmppkt.o
 OBJS-$(CONFIG_RTP_PROTOCOL)              += rtpproto.o
 OBJS-$(CONFIG_SCTP_PROTOCOL)             += sctp.o
+OBJS-$(CONFIG_SRTP_PROTOCOL)             += srtpproto.o srtp.o
 OBJS-$(CONFIG_TCP_PROTOCOL)              += tcp.o
 OBJS-$(CONFIG_TLS_PROTOCOL)              += tls.o
 OBJS-$(CONFIG_UDP_PROTOCOL)              += udp.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 34cf566..4aae223 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -280,6 +280,7 @@ void av_register_all(void)
     REGISTER_PROTOCOL(RTMPTS,           rtmpts);
     REGISTER_PROTOCOL(RTP,              rtp);
     REGISTER_PROTOCOL(SCTP,             sctp);
+    REGISTER_PROTOCOL(SRTP,             srtp);
     REGISTER_PROTOCOL(TCP,              tcp);
     REGISTER_PROTOCOL(TLS,              tls);
     REGISTER_PROTOCOL(UDP,              udp);
diff --git a/libavformat/srtpproto.c b/libavformat/srtpproto.c
new file mode 100644
index 0000000..1cacfdb
--- /dev/null
+++ b/libavformat/srtpproto.c
@@ -0,0 +1,144 @@
+/*
+ * SRTP network protocol
+ * Copyright (c) 2012 Martin Storsjo
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/opt.h"
+#include "avformat.h"
+#include "avio_internal.h"
+#include "url.h"
+
+#include "internal.h"
+#include "srtp.h"
+
+typedef struct SRTPProtoContext {
+    const AVClass *class;
+    URLContext *rtp_hd;
+    const char *out_suite, *out_params;
+    const char *in_suite, *in_params;
+    struct SRTPContext srtp_out, srtp_in;
+    uint8_t encryptbuf[1500];
+} SRTPProtoContext;
+
+#define D AV_OPT_FLAG_DECODING_PARAM
+#define E AV_OPT_FLAG_ENCODING_PARAM
+static const AVOption options[] = {
+    { "srtp_out_suite", "", offsetof(SRTPProtoContext, out_suite), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
+    { "srtp_out_params", "", offsetof(SRTPProtoContext, out_params), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
+    { "srtp_in_suite", "", offsetof(SRTPProtoContext, in_suite), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
+    { "srtp_in_params", "", offsetof(SRTPProtoContext, in_params), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
+    { NULL }
+};
+
+static const AVClass srtp_context_class = {
+    .class_name     = "srtp",
+    .item_name      = av_default_item_name,
+    .option         = options,
+    .version        = LIBAVUTIL_VERSION_INT,
+};
+
+static int srtp_close(URLContext *h)
+{
+    SRTPProtoContext *s = h->priv_data;
+    ff_srtp_free(&s->srtp_out);
+    ff_srtp_free(&s->srtp_in);
+    ffurl_close(s->rtp_hd);
+    s->rtp_hd = NULL;
+    return 0;
+}
+
+static int srtp_open(URLContext *h, const char *uri, int flags)
+{
+    SRTPProtoContext *s = h->priv_data;
+    char hostname[256], buf[1024], path[1024];
+    int rtp_port, ret;
+
+    if (s->out_suite && s->out_params)
+        if ((ret = ff_srtp_set_crypto(&s->srtp_out, s->out_suite, s->out_params)) < 0)
+            goto fail;
+    if (s->in_suite && s->in_params)
+        if ((ret = ff_srtp_set_crypto(&s->srtp_in, s->in_suite, s->in_params)) < 0)
+            goto fail;
+
+    av_url_split(NULL, 0, NULL, 0, hostname, sizeof(hostname), &rtp_port,
+                 path, sizeof(path), uri);
+    ff_url_join(buf, sizeof(buf), "rtp", NULL, hostname, rtp_port, "%s", path);
+    if ((ret = ffurl_open(&s->rtp_hd, buf, flags, &h->interrupt_callback, NULL)) < 0)
+        goto fail;
+
+    h->max_packet_size = FFMIN(s->rtp_hd->max_packet_size,
+                               sizeof(s->encryptbuf)) - 14;
+    h->is_streamed = 1;
+    return 0;
+
+fail:
+    srtp_close(h);
+    return ret;
+}
+
+static int srtp_read(URLContext *h, uint8_t *buf, int size)
+{
+    SRTPProtoContext *s = h->priv_data;
+    int ret;
+start:
+    ret = ffurl_read(s->rtp_hd, buf, size);
+    if (ret > 0 && s->srtp_in.aes) {
+        if (ff_srtp_decrypt(&s->srtp_in, buf, &ret) < 0)
+            goto start;
+    }
+    return ret;
+}
+
+static int srtp_write(URLContext *h, const uint8_t *buf, int size)
+{
+    SRTPProtoContext *s = h->priv_data;
+    if (!s->srtp_out.aes)
+        return ffurl_write(s->rtp_hd, buf, size);
+    size = ff_srtp_encrypt(&s->srtp_out, buf, size, s->encryptbuf,
+                           sizeof(s->encryptbuf));
+    if (size < 0)
+        return size;
+    return ffurl_write(s->rtp_hd, s->encryptbuf, size);
+}
+
+static int srtp_get_file_handle(URLContext *h)
+{
+    SRTPProtoContext *s = h->priv_data;
+    return ffurl_get_file_handle(s->rtp_hd);
+}
+
+static int srtp_get_multi_file_handle(URLContext *h, int **handles,
+                                      int *numhandles)
+{
+    SRTPProtoContext *s = h->priv_data;
+    return ffurl_get_multi_file_handle(s->rtp_hd, handles, numhandles);
+}
+
+URLProtocol ff_srtp_protocol = {
+    .name                      = "srtp",
+    .url_open                  = srtp_open,
+    .url_read                  = srtp_read,
+    .url_write                 = srtp_write,
+    .url_close                 = srtp_close,
+    .url_get_file_handle       = srtp_get_file_handle,
+    .url_get_multi_file_handle = srtp_get_multi_file_handle,
+    .priv_data_size            = sizeof(SRTPProtoContext),
+    .priv_data_class           = &srtp_context_class,
+    .flags                     = URL_PROTOCOL_FLAG_NETWORK,
+};
diff --git a/libavformat/version.h b/libavformat/version.h
index cb6bc77..89f1f6c 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -30,8 +30,8 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFORMAT_VERSION_MAJOR 54
-#define LIBAVFORMAT_VERSION_MINOR 20
-#define LIBAVFORMAT_VERSION_MICRO  5
+#define LIBAVFORMAT_VERSION_MINOR 21
+#define LIBAVFORMAT_VERSION_MICRO  0
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \



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