gapk: Add support for RTP input/output streams

Instead of having only file-based I/O, this enables gapk to receive and
send RTP streams, e.g. from live GSM network equipment like
sysmoBTS/nanoBTS.

Support is currently simplistic.  On transmit, there is hard-coded codec
type of full-rate GSM.  On receive-side, we should auto-detect the
format based on frame size and/or payload type, but we don't do that yet
at all.

5 files changed, 349 insertions, 13 deletions

diff --git a/configure.ac b/configure.ac
index 0b0968d..1208025 100644
--- a/configure.ac
+++ b/configure.ac
@@ -49,6 +49,7 @@ AC_PROG_LIBTOOL
 
 # Checks for libraries.
  # libosmocore (codec module)
+PKG_CHECK_MODULES(LIBOSMOCORE, libosmocore >= 0.3.2)
 PKG_CHECK_MODULES(LIBOSMOCODEC, libosmocodec >= 0.1.25)
 
  # opencore-amrnb for AMR and EFR decoding
diff --git a/include/gapk/procqueue.h b/include/gapk/procqueue.h
index ba1e2fa..93893ca 100644
--- a/include/gapk/procqueue.h
+++ b/include/gapk/procqueue.h
@@ -44,6 +44,11 @@ int			pq_execute(struct pq *pq);
 int pq_queue_file_input(struct pq *pq, FILE *src, unsigned int block_len);
 int pq_queue_file_output(struct pq *pq, FILE *dst, unsigned int block_len);
 
+/* RTP */
+int pq_queue_rtp_input(struct pq *pq, int rtp_fd, unsigned int block_len);
+int pq_queue_rtp_output(struct pq *pq, int rtp_fd, unsigned int block_len);
+
+
 /* Format */
 struct format_desc;
 int pq_queue_fmt_convert(struct pq *pq, const struct format_desc *fmt, int to_from_n);
diff --git a/src/Makefile.am b/src/Makefile.am
index 55a6a5d..c17dd3f 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,14 +1,18 @@
 INCLUDES = $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)
-AM_CFLAGS=-Wall $(LIBOSMOCODEC_CFLAGS) ${OPENCORE_AMRNB_CFLAGS}
-AM_LDFLAGS=$(LIBOSMOCODEC_LIBS) ${OPENCORE_AMRNB_LIBS} ${LIBGSM_LIBS}
+AM_CFLAGS=-Wall $(LIBOSMOCODEC_CFLAGS) $(LIBOSMOCORE_CFLAGS) \
+	  ${OPENCORE_AMRNB_CFLAGS}
+AM_LDFLAGS=$(LIBOSMOCODEC_LIBS) $(LIBOSMOCORE_LIBS) \
+	   ${OPENCORE_AMRNB_LIBS} ${LIBGSM_LIBS}
 
-bin_PROGRAMS = gapk
-gapk_SOURCES =	main.c	\
-		procqueue.c pq_file.c pq_format.c pq_codec.c \
+COM_SOURCES = procqueue.c pq_file.c pq_format.c pq_codec.c pq_rtp.c \
 		formats.c fmt_amr.c fmt_gsm.c fmt_hr_ref.c fmt_racal.c \
 			fmt_rawpcm.c fmt_ti.c \
 		codecs.c codec_pcm.c codec_hr.c codec_fr.c codec_efr.c
 
+bin_PROGRAMS = gapk
+
+gapk_SOURCES =	main.c $(COM_SOURCES)
+
 if ENABLE_GSMHR
 gapk_LDADD = $(top_builddir)/libgsmhr/libgsmhr.la
 endif
diff --git a/src/main.c b/src/main.c
index 9b49445..fd91d4b 100644
--- a/src/main.c
+++ b/src/main.c
@@ -25,6 +25,11 @@
 #include <unistd.h>
 #include <getopt.h>
 
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+#include <osmocom/core/socket.h>
+
 #include <gapk/codecs.h>
 #include <gapk/formats.h>
 #include <gapk/procqueue.h>
@@ -33,9 +38,17 @@
 struct gapk_options
 {
 	const char *fname_in;
+	struct {
+		const char *hostname;
+		uint16_t port;
+	} rtp_in;
 	const struct format_desc *fmt_in;
 
 	const char *fname_out;
+	struct {
+		const char *hostname;
+		uint16_t port;
+	} rtp_out;
 	const struct format_desc *fmt_out;
 };
 
@@ -45,7 +58,7 @@ struct gapk_state
 
 	struct pq *pq;
 
-	union {
+	struct {
 		struct {
 			FILE *fh;
 		} file;
@@ -54,7 +67,7 @@ struct gapk_state
 		} rtp;
 	} in;
 
-	union {
+	struct {
 		struct {
 			FILE *fh;
 		} file;
@@ -75,7 +88,9 @@ print_help(char *progname)
 	fprintf(stdout, "\n");
 	fprintf(stdout, "Options:\n");
 	fprintf(stdout, "  -i, --input-file=FILE\t\tInput file\n");
+	fprintf(stdout, "  -I, --input-rtp=HOST/PORT\t\tInput RTP stream\n");
 	fprintf(stdout, "  -o, --output-file=FILE\tOutput file\n");
+	fprintf(stdout, "  -O, --output-rtp=HOST/PORT\tOutput RTP stream\n");
 	fprintf(stdout, "  -f, --input-format=FMT\tInput format (see below)\n");
 	fprintf(stdout, "  -g, --output-format=FMT\tOutput format (see below)\n");
 	fprintf(stdout, "\n");
@@ -114,16 +129,39 @@ print_help(char *progname)
 }
 
 static int
+parse_host_port(const char *host_port, const char **host)
+{
+	char *dup = strdup(host_port);
+	char *tok;
+
+	if (!dup)
+		return -ENOMEM;
+
+	tok = strtok(dup, "/");
+	if (!tok)
+		return -EINVAL;
+	*host = tok;
+
+	tok = strtok(NULL, "/");
+	if (!tok)
+		return -EINVAL;
+
+	return atoi(tok);
+}
+
+static int
 parse_options(struct gapk_state *state, int argc, char *argv[])
 {
 	const struct option long_options[] = {
 		{"input-file", 1, 0, 'i'},
 		{"output-file", 1, 0, 'o'},
+		{"input-rtp", 1, 0, 'I'},
+		{"output-rtp", 1, 0, 'O'},
 		{"input-format", 1, 0, 'f'},
 		{"output-format", 1, 0, 'g'},
 		{"help", 0, 0, 'h'},
 	};
-	const char *short_options = "i:o:f:g:h";
+	const char *short_options = "i:o:I:O:f:g:h";
 
 	struct gapk_options *opt = &state->opts;
 
@@ -132,7 +170,7 @@ parse_options(struct gapk_state *state, int argc, char *argv[])
 
 	/* Parse */
 	while (1) {
-		int c;
+		int c, rv;
 		int opt_idx;
 
 		c = getopt_long(
@@ -149,6 +187,24 @@ parse_options(struct gapk_state *state, int argc, char *argv[])
 			opt->fname_out = optarg;
 			break;
 
+		case 'I':
+			rv = parse_host_port(optarg, &opt->rtp_in.hostname);
+			if (rv < 0 || rv > 0xffff) {
+				fprintf(stderr, "[!] Invalid port: %d\n", rv);
+				return -EINVAL;
+			}
+			opt->rtp_in.port = rv;
+			break;
+
+		case 'O':
+			rv = parse_host_port(optarg, &opt->rtp_out.hostname);
+			if (rv < 0 || rv > 0xffff) {
+				fprintf(stderr, "[!] Invalid port: %d\n", rv);
+				return -EINVAL;
+			}
+			opt->rtp_out.port = rv;
+			break;
+
 		case 'f':
 			opt->fmt_in = fmt_get_from_name(optarg);
 			if (!opt->fmt_in) {
@@ -214,6 +270,18 @@ check_options(struct gapk_state *gs)
 		}
 	}
 
+	/* Input combinations */
+	if (gs->opts.fname_in && gs->opts.rtp_in.port) {
+		fprintf(stderr, "[!] You have to decide on either file or RTP input\n");
+		return -EINVAL;
+	}
+
+	/* Output combinations */
+	if (gs->opts.fname_out && gs->opts.rtp_out.port) {
+		fprintf(stderr, "[!] You have to decide on either file or RTP output\n");
+		return -EINVAL;
+	}
+
 	return 0;
 }
 
@@ -227,6 +295,16 @@ files_open(struct gapk_state *gs)
 			perror("fopen");
 			return -errno;
 		}
+	} else if (gs->opts.rtp_in.port) {
+		gs->in.rtp.fd = osmo_sock_init(AF_UNSPEC, SOCK_DGRAM,
+						IPPROTO_UDP,
+						gs->opts.rtp_in.hostname,
+						gs->opts.rtp_in.port,
+						OSMO_SOCK_F_BIND);
+		if (gs->in.rtp.fd < 0) {
+			fprintf(stderr, "[!] Error while opening input socket\n");
+			return gs->in.rtp.fd;
+		}
 	} else
 		gs->in.file.fh = stdin;
 
@@ -237,6 +315,16 @@ files_open(struct gapk_state *gs)
 			perror("fopen");
 			return -errno;
 		}
+	} else if (gs->opts.rtp_out.port) {
+		gs->out.rtp.fd = osmo_sock_init(AF_UNSPEC, SOCK_DGRAM,
+						IPPROTO_UDP,
+						gs->opts.rtp_out.hostname,
+						gs->opts.rtp_out.port,
+						OSMO_SOCK_F_CONNECT);
+		if (gs->out.rtp.fd < 0) {
+			fprintf(stderr, "[!] Error while opening output socket\n");
+			return gs->out.rtp.fd;
+		}
 	} else
 		gs->out.file.fh = stdout;
 
@@ -248,8 +336,12 @@ files_close(struct gapk_state *gs)
 {
 	if (gs->in.file.fh && gs->in.file.fh != stdin)
 		fclose(gs->in.file.fh);
+	if (gs->in.rtp.fd >= 0)
+		close(gs->in.rtp.fd);
 	if (gs->out.file.fh && gs->out.file.fh != stdout)
 		fclose(gs->out.file.fh);
+	if (gs->out.rtp.fd >= 0)
+		close(gs->out.rtp.fd);
 }
 
 static int
@@ -260,7 +352,7 @@ handle_headers(struct gapk_state *gs)
 
 	/* Input file header (remove & check it) */
 	len = gs->opts.fmt_in->header_len;
-	if (len) {
+	if (len && gs->in.file.fh) {
 		uint8_t *buf;
 		
 		buf = malloc(len);
@@ -281,7 +373,7 @@ handle_headers(struct gapk_state *gs)
 
 	/* Output file header (write it) */
 	len = gs->opts.fmt_out->header_len;
-	if (len) {
+	if (len && gs->out.file.fh) {
 		rv = fwrite(gs->opts.fmt_out->header, len, 1, gs->out.file.fh);
 		if (rv != 1)
 			return -ENOSPC;
@@ -310,7 +402,10 @@ make_processing_chain(struct gapk_state *gs)
 	           (fmt_out->codec_type != fmt_in->codec_type);
 
 	/* File read */
-	pq_queue_file_input(gs->pq, gs->in.file.fh, fmt_in->frame_len);
+	if (gs->in.file.fh)
+		pq_queue_file_input(gs->pq, gs->in.file.fh, fmt_in->frame_len);
+	else
+		pq_queue_rtp_input(gs->pq, gs->in.rtp.fd, fmt_in->frame_len);
 
 	/* Decoding to PCM ? */
 	if (need_dec)
@@ -363,7 +458,10 @@ make_processing_chain(struct gapk_state *gs)
 	}
 
 	/* File write */
-	pq_queue_file_output(gs->pq, gs->out.file.fh, fmt_out->frame_len);
+	if (gs->out.file.fh)
+		pq_queue_file_output(gs->pq, gs->out.file.fh, fmt_out->frame_len);
+	else
+		pq_queue_rtp_output(gs->pq, gs->out.rtp.fd, fmt_out->frame_len);
 
 	return 0;
 }
@@ -391,6 +489,8 @@ int main(int argc, char *argv[])
 
 	/* Clear state */
 	memset(gs, 0x00, sizeof(struct gapk_state));
+	gs->in.rtp.fd = -1;
+	gs->out.rtp.fd = -1;
 
 	/* Parse / check options */
 	rv = parse_options(gs, argc, argv);
diff --git a/src/pq_rtp.c b/src/pq_rtp.c
new file mode 100644
index 0000000..87e0f2e
--- /dev/null
+++ b/src/pq_rtp.c
@@ -0,0 +1,226 @@
+/* Process Queue: RTP handling tasks */
+
+/* (C) 2013 by Harald Welte <laforge@gnumonks.org>
+ *
+ * This file is part of gapk (GSM Audio Pocket Knife).
+ *
+ * gapk is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * gapk 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with gapk.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <errno.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <arpa/inet.h>
+
+#include <gapk/codecs.h>
+#include <gapk/formats.h>
+#include <gapk/procqueue.h>
+
+#ifndef __BYTE_ORDER
+# ifdef __APPLE__
+#  define __BYTE_ORDER __DARWIN_BYTE_ORDER
+#  define __LITTLE_ENDIAN __DARWIN_LITTLE_ENDIAN
+#  define __BIG_ENDIAN __DARWIN_BIG_ENDIAN
+# else
+#  error "__BYTE_ORDER should be defined by someone"
+# endif
+#endif
+
+/* according to RFC 3550 */
+struct rtp_hdr {
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+	uint8_t  csrc_count:4,
+		  extension:1,
+		  padding:1,
+		  version:2;
+	uint8_t  payload_type:7,
+		  marker:1;
+#elif __BYTE_ORDER == __BIG_ENDIAN
+	uint8_t  version:2,
+		  padding:1,
+		  extension:1,
+		  csrc_count:4;
+	uint8_t  marker:1,
+		  payload_type:7;
+#endif
+	uint16_t sequence;
+	uint32_t timestamp;
+	uint32_t ssrc;
+} __attribute__((packed));
+
+struct rtp_x_hdr {
+	uint16_t by_profile;
+	uint16_t length;
+} __attribute__((packed));
+
+#define RTP_VERSION	2
+
+#define RTP_PT_GSM_FULL 3
+
+struct pq_state_rtp {
+	int fd;
+	int blk_len;
+
+	/* configurable */
+	uint32_t duration;
+	uint8_t payload_type;
+
+	/* auto-increment */
+	uint16_t sequence;
+	uint32_t timestamp;
+	uint32_t ssrc;
+};
+
+
+static int
+pq_cb_rtp_input(void *_state, uint8_t *out, const uint8_t *in)
+{
+	struct pq_state_rtp *state = _state;
+	uint8_t buf[state->blk_len+256];
+	struct rtp_hdr *rtph = (struct rtp_hdr *)buf;
+	struct rtp_x_hdr *rtpxh;
+	uint8_t *payload;
+	int rv, x_len, payload_len;
+
+	rv = read(state->fd, buf, sizeof(buf));
+	if (rv <= 0)
+		return -1;
+
+	if (rv < sizeof(struct rtp_hdr))
+		return -1;
+
+	if (rtph->version != RTP_VERSION)
+		return -1;
+
+	payload = buf + sizeof(struct rtp_hdr) + (rtph->csrc_count << 2);
+	payload_len = rv - sizeof(struct rtp_hdr) - (rtph->csrc_count << 2);
+	if (payload_len < 0)
+		return -1;
+
+	if (rtph->extension) {
+		if (payload_len < sizeof(struct rtp_x_hdr))
+			return -1;
+		rtpxh = (struct rtp_x_hdr *)payload;
+		x_len = ntohs(rtpxh->length) * 4 + sizeof(struct rtp_x_hdr);
+		payload += x_len;
+		payload_len -= x_len;
+		if (payload_len < 0)
+			return -1;
+	}
+	if (rtph->padding) {
+		if (payload_len < 0)
+			return -1;
+		payload_len -= payload[payload_len -1];
+		if (payload_len < 0)
+			return -1;
+	}
+
+	state->ssrc = ntohl(rtph->ssrc);
+	state->timestamp = ntohl(rtph->timestamp);
+	state->sequence = ntohs(rtph->sequence);
+	/* FIXME: check for discontinuity, ... */
+
+	memcpy(out, payload, payload_len);
+
+	return 0;
+}
+
+static int
+pq_cb_rtp_output(void *_state, uint8_t *out, const uint8_t *in)
+{
+	struct pq_state_rtp *state = _state;
+	int len = state->blk_len + sizeof(struct rtp_hdr);
+	uint8_t buf[len];
+	struct rtp_hdr *rtph = (struct rtp_hdr *)buf;
+	uint8_t *payload;
+	int rv;
+
+	rtph->version = RTP_VERSION;
+	rtph->padding = 0;
+	rtph->extension = 0;
+	rtph->csrc_count = 0;
+	rtph->marker = 0;
+	rtph->payload_type = state->payload_type;
+	rtph->sequence = htons(state->sequence++);
+	rtph->timestamp = htonl(state->timestamp);
+	state->timestamp += state->duration;
+	rtph->ssrc = htonl(state->ssrc);
+
+	payload = buf + sizeof(*rtph);
+	memcpy(payload, in, state->blk_len);
+
+	rv = write(state->fd, buf, len);
+	return rv == len ? 0 : -1;
+}
+
+static void
+pq_cb_rtp_exit(void *_state)
+{
+	free(_state);
+}
+
+static int
+pq_queue_rtp_op(struct pq *pq, int udp_fd, unsigned int blk_len, int in_out_n)
+{
+	struct pq_item *item;
+	struct pq_state_rtp *state;
+
+	state = calloc(1, sizeof(struct pq_state_rtp));
+	if (!state)
+		return -ENOMEM;
+
+	state->fd = udp_fd;
+	state->blk_len = blk_len;
+
+	state->duration = 160;
+
+	if (in_out_n == 0) {
+		state->ssrc = rand();
+		state->sequence = random();
+		state->timestamp = random();
+		/* FIXME: other payload types!! */
+		state->payload_type = RTP_PT_GSM_FULL;
+	}
+
+	item = pq_add_item(pq);
+	if (!item) {
+		free(state);
+		return -ENOMEM;
+	}
+
+	item->len_in  = in_out_n ? 0 : blk_len;
+	item->len_out = in_out_n ? blk_len : 0;
+	item->state   = state;
+	item->proc    = in_out_n ? pq_cb_rtp_input : pq_cb_rtp_output;
+	item->exit    = pq_cb_rtp_exit;
+
+	return 0;
+}
+
+
+int
+pq_queue_rtp_input(struct pq *pq, int udp_fd, unsigned int blk_len)
+{
+	return pq_queue_rtp_op(pq, udp_fd, blk_len, 1);
+}
+
+int
+pq_queue_rtp_output(struct pq *pq, int udp_fd, unsigned int blk_len)
+{
+	return pq_queue_rtp_op(pq, udp_fd, blk_len, 0);
+}