split off osmo-mgw: remove files, apply build, rename

Add vty and logging previously used from libcommon

Rename libmgcp to libosmo-legacy-mgcp and install.

Use DLMGCP, not DMGCP.

Slim down the public mgcpgw_client API, move all elements not actually used by
current callers to private headers / static c.

Depends: libosmocore I09c587e2d59472cbde852d467d457254746d9e67
Change-Id: I71a0a16ebaaef881c34235849601fc40aa12cfd7
diff --git a/tests/legacy_mgcp/mgcp_transcoding_test.c b/tests/legacy_mgcp/mgcp_transcoding_test.c
new file mode 100644
index 0000000..61de25f
--- /dev/null
+++ b/tests/legacy_mgcp/mgcp_transcoding_test.c
@@ -0,0 +1,661 @@
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <err.h>
+#include <stdint.h>
+#include <errno.h>
+
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/application.h>
+
+#include <osmocom/netif/rtp.h>
+
+#include <osmocom/legacy_mgcp/mgcp.h>
+#include <osmocom/legacy_mgcp/mgcp_internal.h>
+
+#include "bscconfig.h"
+#ifndef BUILD_MGCP_TRANSCODING
+#error "Requires MGCP transcoding enabled (see --enable-mgcp-transcoding)"
+#endif
+
+#include <osmocom/legacy_mgcp/mgcp_transcode.h>
+
+uint8_t *audio_frame_l16[] = {
+};
+
+struct rtp_packets {
+	float t;
+	int len;
+	char *data;
+};
+
+struct rtp_packets audio_packets_l16[] = {
+	/* RTP: SeqNo=1, TS=160 */
+	{0.020000, 332,
+		"\x80\x0B\x00\x01\x00\x00\x00\xA0\x11\x22\x33\x44"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+		"\x00\x00\x40\x13\x5A\x9E\x40\x13\x00\x00\xBF\xED\xA5\x62\xBF\xED"
+	},
+};
+
+struct rtp_packets audio_packets_gsm[] = {
+	/* RTP: SeqNo=1, TS=160 */
+	{0.020000, 45,
+		"\x80\x03\x00\x01\x00\x00\x00\xA0\x11\x22\x33\x44"
+		"\xD4\x7C\xE3\xE9\x62\x50\x39\xF0\xF8\xB4\x68\xEA\x6C\x0E\x81\x1B"
+		"\x56\x2A\xD5\xBC\x69\x9C\xD1\xF0\x66\x7A\xEC\x49\x7A\x33\x3D\x0A"
+		"\xDE"
+	},
+};
+
+struct rtp_packets audio_packets_gsm_invalid_size[] = {
+	/* RTP: SeqNo=1, TS=160 */
+	{0.020000, 41,
+		"\x80\x03\x00\x01\x00\x00\x00\xA0\x11\x22\x33\x44"
+		"\xD4\x7C\xE3\xE9\x62\x50\x39\xF0\xF8\xB4\x68\xEA\x6C\x0E\x81\x1B"
+		"\x56\x2A\xD5\xBC\x69\x9C\xD1\xF0\x66\x7A\xEC\x49\x7A\x33\x3D\x0A"
+		"\xDE"
+	},
+};
+
+struct rtp_packets audio_packets_gsm_invalid_data[] = {
+	/* RTP: SeqNo=1, TS=160 */
+	{0.020000, 45,
+		"\x80\x03\x00\x01\x00\x00\x00\xA0\x11\x22\x33\x44"
+		"\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE"
+		"\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE\xEE"
+		"\xEE"
+	},
+};
+
+struct rtp_packets audio_packets_gsm_invalid_ptype[] = {
+	/* RTP: SeqNo=1, TS=160 */
+	{0.020000, 45,
+		"\x80\x08\x00\x01\x00\x00\x00\xA0\x11\x22\x33\x44"
+		"\xD4\x7C\xE3\xE9\x62\x50\x39\xF0\xF8\xB4\x68\xEA\x6C\x0E\x81\x1B"
+		"\x56\x2A\xD5\xBC\x69\x9C\xD1\xF0\x66\x7A\xEC\x49\x7A\x33\x3D\x0A"
+		"\xDE"
+	},
+};
+
+struct rtp_packets audio_packets_g729[] = {
+	/* RTP: SeqNo=1, TS=160 */
+	{0.020000, 32,
+		"\x80\x12\x00\x01\x00\x00\x00\xA0\x11\x22\x33\x44"
+		"\xAF\xC2\x81\x40\x00\xFA\xCE\xA4\x21\x7C\xC5\xC3\x4F\xA5\x98\xF5"
+		"\xB2\x95\xC4\xAD"
+	},
+};
+
+struct rtp_packets audio_packets_pcma[] = {
+	/* RTP: SeqNo=1, TS=160 */
+	{0.020000, 172,
+		"\x80\x08\x00\x01\x00\x00\x00\xA0\x11\x22\x33\x44"
+		"\xD5\xA5\xA3\xA5\xD5\x25\x23\x25\xD5\xA5\xA3\xA5\xD5\x25\x23\x25"
+		"\xD5\xA5\xA3\xA5\xD5\x25\x23\x25\xD5\xA5\xA3\xA5\xD5\x25\x23\x25"
+		"\xD5\xA5\xA3\xA5\xD5\x25\x23\x25\xD5\xA5\xA3\xA5\xD5\x25\x23\x25"
+		"\xD5\xA5\xA3\xA5\xD5\x25\x23\x25\xD5\xA5\xA3\xA5\xD5\x25\x23\x25"
+		"\xD5\xA5\xA3\xA5\xD5\x25\x23\x25\xD5\xA5\xA3\xA5\xD5\x25\x23\x25"
+		"\xD5\xA5\xA3\xA5\xD5\x25\x23\x25\xD5\xA5\xA3\xA5\xD5\x25\x23\x25"
+		"\xD5\xA5\xA3\xA5\xD5\x25\x23\x25\xD5\xA5\xA3\xA5\xD5\x25\x23\x25"
+		"\xD5\xA5\xA3\xA5\xD5\x25\x23\x25\xD5\xA5\xA3\xA5\xD5\x25\x23\x25"
+		"\xD5\xA5\xA3\xA5\xD5\x25\x23\x25\xD5\xA5\xA3\xA5\xD5\x25\x23\x25"
+		"\xD5\xA5\xA3\xA5\xD5\x25\x23\x25\xD5\xA5\xA3\xA5\xD5\x25\x23\x25"
+	},
+	/* RTP: SeqNo=26527, TS=232640 */
+	{0.020000, 92,
+		"\x80\x08\x67\x9f\x00\x03\x8c\xc0\x04\xaa\x67\x9f\xd5\xd5\xd5\xd5"
+		"\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5"
+		"\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5"
+		"\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5\xd5"
+		"\xd5\xd5\xd5\xd5\xd5\xd5\x55\x55\xd5\xd5\x55\x55\xd5\xd5\x55\x55"
+		"\xd5\xd5\xd5\x55\x55\xd5\xd5\xd5\x55\x55\xd5\xd5"
+	},
+	/* RTP: SeqNo=26528, TS=232720 */
+	{0.020000, 92,
+		"\x80\x08\x67\xa0\x00\x03\x8d\x10\x04\xaa\x67\x9f\x55\xd5\xd5\x55"
+		"\xd5\x55\xd5\xd5\xd5\x55\xd5\x55\xd5\xd5\x55\xd5\x55\xd5\x55\xd5"
+		"\x55\x55\xd5\x55\xd5\xd5\x55\x55\x55\x55\x55\xd5\xd5\x55\xd5\xd5"
+		"\xd5\x55\xd5\xd5\xd5\x55\x54\x55\xd5\xd5\x55\xd5\xd5\xd5\xd5\x55"
+		"\x54\x55\xd5\x55\xd5\x55\x55\x55\x55\x55\xd5\xd5\xd5\xd5\xd5\xd4"
+		"\xd5\x54\x55\xd5\xd4\xd5\x54\xd5\x55\xd5\xd5\xd5"
+	},
+};
+
+
+
+static int audio_name_to_type(const char *name)
+{
+	if (!strcasecmp(name, "gsm"))
+		return 3;
+#ifdef HAVE_BCG729
+	else if (!strcasecmp(name, "g729"))
+		return 18;
+#endif
+	else if (!strcasecmp(name, "pcma"))
+		return 8;
+	else if (!strcasecmp(name, "l16"))
+		return 11;
+	return -1;
+}
+
+int mgcp_get_trans_frame_size(void *state_, int nsamples, int dst);
+
+static int given_configured_endpoint(int in_samples, int out_samples,
+				const char *srcfmt, const char *dstfmt,
+				void **out_ctx, struct mgcp_endpoint **out_endp)
+{
+	int rc;
+	struct mgcp_rtp_end *dst_end;
+	struct mgcp_rtp_end *src_end;
+	struct mgcp_config *cfg;
+	struct mgcp_trunk_config *tcfg;
+	struct mgcp_endpoint *endp;
+
+	cfg = mgcp_config_alloc();
+	tcfg = talloc_zero(cfg, struct mgcp_trunk_config);
+	endp = talloc_zero(tcfg, struct mgcp_endpoint);
+
+	cfg->setup_rtp_processing_cb = mgcp_transcoding_setup;
+	cfg->rtp_processing_cb = mgcp_transcoding_process_rtp;
+	cfg->get_net_downlink_format_cb = mgcp_transcoding_net_downlink_format;
+
+	tcfg->endpoints = endp;
+	tcfg->number_endpoints = 1;
+	tcfg->cfg = cfg;
+	endp->tcfg = tcfg;
+	endp->cfg = cfg;
+	mgcp_initialize_endp(endp);
+
+	dst_end = &endp->bts_end;
+	dst_end->codec.payload_type = audio_name_to_type(dstfmt);
+
+	src_end = &endp->net_end;
+	src_end->codec.payload_type = audio_name_to_type(srcfmt);
+
+	if (out_samples) {
+		dst_end->codec.frame_duration_den = dst_end->codec.rate;
+		dst_end->codec.frame_duration_num = out_samples;
+		dst_end->frames_per_packet = 1;
+		dst_end->force_output_ptime = 1;
+	}
+
+	rc = mgcp_transcoding_setup(endp, dst_end, src_end);
+	if (rc < 0) {
+		printf("setup failed: %s", strerror(-rc));
+		abort();
+	}
+
+	*out_ctx = cfg;
+	*out_endp = endp;
+	return 0;
+}
+
+
+static int transcode_test(const char *srcfmt, const char *dstfmt,
+			  uint8_t *src_pkts, size_t src_pkt_size)
+{
+	char buf[4096] = {0x80, 0};
+	void *ctx;
+
+	struct mgcp_rtp_end *dst_end;
+	struct mgcp_process_rtp_state *state;
+	struct mgcp_endpoint *endp;
+	int in_size;
+	const int in_samples = 160;
+	int len, cont;
+
+	printf("== Transcoding test ==\n");
+	printf("converting %s -> %s\n", srcfmt, dstfmt);
+
+	given_configured_endpoint(in_samples, 0, srcfmt, dstfmt, &ctx, &endp);
+
+	dst_end = &endp->bts_end;
+	state = dst_end->rtp_process_data;
+	OSMO_ASSERT(state != NULL);
+
+	in_size = mgcp_transcoding_get_frame_size(state, in_samples, 0);
+	OSMO_ASSERT(sizeof(buf) >= in_size + 12);
+
+	memcpy(buf, src_pkts, src_pkt_size);
+
+	len = src_pkt_size;
+
+	cont = mgcp_transcoding_process_rtp(endp, dst_end,
+					    buf, &len, sizeof(buf));
+	if (cont < 0) {
+		printf("Nothing encoded due: %s\n", strerror(-cont));
+		talloc_free(ctx);
+		return -1;
+	}
+
+	if (len < 24) {
+		printf("encoded: %s\n", osmo_hexdump((unsigned char *)buf, len));
+	} else {
+		const char *str = osmo_hexdump((unsigned char *)buf, len);
+		int i = 0;
+		const int prefix = 4;
+		const int cutlen = 48;
+		int nchars = 0;
+
+		printf("encoded:\n");
+		do {
+			nchars = printf("%*s%-.*s", prefix, "", cutlen, str + i);
+			i += nchars - prefix;
+			printf("\n");
+		} while (nchars - prefix >= cutlen);
+	}
+	printf("counted: %d\n", cont);
+	talloc_free(ctx);
+	return 0;
+}
+
+static void test_rtp_seq_state(void)
+{
+	char buf[4096];
+	int len;
+	int cont;
+	void *ctx;
+	struct mgcp_endpoint *endp;
+	struct mgcp_process_rtp_state *state;
+	struct rtp_hdr *hdr;
+	uint32_t ts_no;
+	uint16_t seq_no;
+
+	given_configured_endpoint(160, 0, "pcma", "l16", &ctx, &endp);
+	state = endp->bts_end.rtp_process_data;
+	OSMO_ASSERT(!state->is_running);
+	OSMO_ASSERT(state->next_seq == 0);
+	OSMO_ASSERT(state->next_time == 0);
+
+	/* initialize packet */
+	len = audio_packets_pcma[0].len;
+	memcpy(buf, audio_packets_pcma[0].data, len);
+	cont = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, len);
+	OSMO_ASSERT(cont >= 0);
+	OSMO_ASSERT(state->is_running);
+	OSMO_ASSERT(state->next_seq == 2);
+	OSMO_ASSERT(state->next_time == 240);
+
+	/* verify that the right timestamp was written */
+	OSMO_ASSERT(len == audio_packets_pcma[0].len);
+	hdr = (struct rtp_hdr *) &buf[0];
+
+	memcpy(&ts_no, &hdr->timestamp, sizeof(ts_no));
+	OSMO_ASSERT(htonl(ts_no) == 160);
+	memcpy(&seq_no, &hdr->sequence, sizeof(seq_no));
+	OSMO_ASSERT(htons(seq_no) == 1);
+	/* Check the right sequence number is written */
+	state->next_seq = 1234;
+	len = audio_packets_pcma[0].len;
+	memcpy(buf, audio_packets_pcma[0].data, len);
+	cont = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, len);
+	OSMO_ASSERT(cont >= 0);
+	OSMO_ASSERT(len == audio_packets_pcma[0].len);
+	hdr = (struct rtp_hdr *) &buf[0];
+
+	memcpy(&seq_no, &hdr->sequence, sizeof(seq_no));
+	OSMO_ASSERT(htons(seq_no) == 1234);
+
+	talloc_free(ctx);
+}
+
+static void test_transcode_result(void)
+{
+	char buf[4096];
+	int len, res;
+	void *ctx;
+	struct mgcp_endpoint *endp;
+	struct mgcp_process_rtp_state *state;
+
+	{
+		/* from GSM to PCMA and same ptime */
+		given_configured_endpoint(160, 0, "gsm", "pcma", &ctx, &endp);
+		state = endp->bts_end.rtp_process_data;
+
+		/* result */
+		len = audio_packets_gsm[0].len;
+		memcpy(buf, audio_packets_gsm[0].data, len);
+		res = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, ARRAY_SIZE(buf));
+		OSMO_ASSERT(res == sizeof(struct rtp_hdr));
+		OSMO_ASSERT(state->sample_cnt == 0);
+
+		len = res;
+		res = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, ARRAY_SIZE(buf));
+		OSMO_ASSERT(res == -ENOMSG);
+
+		talloc_free(ctx);
+	}
+
+	{
+		/* from GSM to PCMA and same ptime */
+		given_configured_endpoint(160, 160, "gsm", "pcma", &ctx, &endp);
+		state = endp->bts_end.rtp_process_data;
+
+		/* result */
+		len = audio_packets_gsm[0].len;
+		memcpy(buf, audio_packets_gsm[0].data, len);
+		res = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, ARRAY_SIZE(buf));
+		OSMO_ASSERT(res == sizeof(struct rtp_hdr));
+		OSMO_ASSERT(state->sample_cnt == 0);
+
+		len = res;
+		res = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, ARRAY_SIZE(buf));
+		OSMO_ASSERT(res == -EAGAIN);
+
+		talloc_free(ctx);
+	}
+
+	{
+		/* from PCMA to GSM and wrong different ptime */
+		given_configured_endpoint(80, 160, "pcma", "gsm", &ctx, &endp);
+		state = endp->bts_end.rtp_process_data;
+
+		/* Add the first sample */
+		len = audio_packets_pcma[1].len;
+		memcpy(buf, audio_packets_pcma[1].data, len);
+		res = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, ARRAY_SIZE(buf));
+		OSMO_ASSERT(state->sample_cnt == 80);
+		OSMO_ASSERT(state->next_time == 232640);
+		OSMO_ASSERT(res < 0);
+
+		/* Add the second sample and it should be consumable */
+		len = audio_packets_pcma[2].len;
+		memcpy(buf, audio_packets_pcma[2].data, len);
+		res = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, ARRAY_SIZE(buf));
+		OSMO_ASSERT(state->sample_cnt == 0);
+		OSMO_ASSERT(state->next_time == 232640 + 80 + 160);
+		OSMO_ASSERT(res == sizeof(struct rtp_hdr));
+
+		talloc_free(ctx);
+	}
+
+	{
+		/* from PCMA to GSM with a big time jump */
+		struct rtp_hdr *hdr;
+		uint32_t ts;
+
+		given_configured_endpoint(80, 160, "pcma", "gsm", &ctx, &endp);
+		state = endp->bts_end.rtp_process_data;
+
+		/* Add the first sample */
+		len = audio_packets_pcma[1].len;
+		memcpy(buf, audio_packets_pcma[1].data, len);
+		res = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, ARRAY_SIZE(buf));
+		OSMO_ASSERT(state->sample_cnt == 80);
+		OSMO_ASSERT(state->next_time == 232640);
+		OSMO_ASSERT(state->next_seq == 26527);
+		OSMO_ASSERT(res < 0);
+
+		/* Add a skip to the packet to force a 'resync' */
+		len = audio_packets_pcma[2].len;
+		memcpy(buf, audio_packets_pcma[2].data, len);
+		hdr = (struct rtp_hdr *) &buf[0];
+		/* jump the time and add alignment error */
+		ts = ntohl(hdr->timestamp) + 123 * 80 + 2;
+		hdr->timestamp = htonl(ts);
+		res = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, ARRAY_SIZE(buf));
+		OSMO_ASSERT(res < 0);
+		OSMO_ASSERT(state->sample_cnt == 80);
+		OSMO_ASSERT(state->next_time == ts);
+		OSMO_ASSERT(state->next_seq == 26527);
+		/* TODO: this can create alignment errors */
+
+
+		/* Now attempt to consume 160 samples */
+		len = audio_packets_pcma[2].len;
+		memcpy(buf, audio_packets_pcma[2].data, len);
+		hdr = (struct rtp_hdr *) &buf[0];
+		ts += 80;
+		hdr->timestamp = htonl(ts);
+		res = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, ARRAY_SIZE(buf));
+		OSMO_ASSERT(res == 12);
+		OSMO_ASSERT(state->sample_cnt == 0);
+		OSMO_ASSERT(state->next_time == ts + 160);
+		OSMO_ASSERT(state->next_seq == 26528);
+
+		talloc_free(ctx);
+	}
+}
+
+static void test_transcode_change(void)
+{
+	char buf[4096] = {0x80, 0};
+	void *ctx;
+
+	struct mgcp_endpoint *endp;
+	struct mgcp_process_rtp_state *state;
+	struct rtp_hdr *hdr;
+
+	int len, res;
+
+	{
+		/* from GSM to PCMA and same ptime */
+		printf("Testing Initial L16->GSM, PCMA->GSM\n");
+		given_configured_endpoint(160, 0, "l16", "gsm", &ctx, &endp);
+		endp->net_end.alt_codec = endp->net_end.codec;
+		endp->net_end.alt_codec.payload_type = audio_name_to_type("pcma");
+		state = endp->bts_end.rtp_process_data;
+
+		/* initial transcoding work */
+		OSMO_ASSERT(state->src_fmt == AF_L16);
+		OSMO_ASSERT(state->dst_fmt == AF_GSM);
+		OSMO_ASSERT(endp->net_end.alt_codec.payload_type == 8);
+		OSMO_ASSERT(endp->net_end.codec.payload_type == 11);
+
+		/* result */
+		len = audio_packets_pcma[0].len;
+		memcpy(buf, audio_packets_pcma[0].data, len);
+		res = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, ARRAY_SIZE(buf));
+		state = endp->bts_end.rtp_process_data;
+		OSMO_ASSERT(res == sizeof(struct rtp_hdr));
+		OSMO_ASSERT(state->sample_cnt == 0);
+		OSMO_ASSERT(state->src_fmt == AF_PCMA);
+		OSMO_ASSERT(state->dst_fmt == AF_GSM);
+		OSMO_ASSERT(endp->net_end.alt_codec.payload_type == 11);
+		OSMO_ASSERT(endp->net_end.codec.payload_type == 8);
+
+		len = res;
+		res = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, ARRAY_SIZE(buf));
+		OSMO_ASSERT(res == -ENOMSG);
+		OSMO_ASSERT(state == endp->bts_end.rtp_process_data);
+
+
+		/* now check that comfort noise doesn't change anything */
+		len = audio_packets_pcma[1].len;
+		memcpy(buf, audio_packets_pcma[1].data, len);
+		hdr = (struct rtp_hdr *) buf;
+		hdr->payload_type = 12;
+		res = mgcp_transcoding_process_rtp(endp, &endp->bts_end, buf, &len, ARRAY_SIZE(buf));
+		OSMO_ASSERT(state == endp->bts_end.rtp_process_data);
+		OSMO_ASSERT(state->sample_cnt == 80);
+		OSMO_ASSERT(state->src_fmt == AF_PCMA);
+		OSMO_ASSERT(state->dst_fmt == AF_GSM);
+		OSMO_ASSERT(endp->net_end.alt_codec.payload_type == 11);
+		OSMO_ASSERT(endp->net_end.codec.payload_type == 8);
+
+		talloc_free(ctx);
+	}
+}
+
+static int test_repacking(int in_samples, int out_samples, int no_transcode)
+{
+	char buf[4096] = {0x80, 0};
+	int cc;
+	struct mgcp_endpoint *endp;
+	void *ctx;
+
+	struct mgcp_process_rtp_state *state;
+	int in_cnt;
+	int out_size;
+	int in_size;
+	uint32_t ts = 0;
+	uint16_t seq = 0;
+	const char *srcfmt = "pcma";
+	const char *dstfmt = no_transcode ? "pcma" : "l16";
+
+	printf("== Transcoding test ==\n");
+	printf("converting %s -> %s\n", srcfmt, dstfmt);
+
+	given_configured_endpoint(in_samples, out_samples, srcfmt, dstfmt, &ctx, &endp);
+
+	state = endp->bts_end.rtp_process_data;
+	OSMO_ASSERT(state != NULL);
+
+	in_size = mgcp_transcoding_get_frame_size(state, in_samples, 0);
+	OSMO_ASSERT(sizeof(buf) >= in_size + 12);
+
+	out_size = mgcp_transcoding_get_frame_size(state, -1, 1);
+	OSMO_ASSERT(sizeof(buf) >= out_size + 12);
+
+	buf[1] = endp->net_end.codec.payload_type;
+	*(uint16_t*)(buf+2) = htons(1);
+	*(uint32_t*)(buf+4) = htonl(0);
+	*(uint32_t*)(buf+8) = htonl(0xaabbccdd);
+
+	for (in_cnt = 0; in_cnt < 16; in_cnt++) {
+		int cont;
+		int len;
+
+		/* fake PCMA data */
+		printf("generating %d %s input samples\n", in_samples, srcfmt);
+		for (cc = 0; cc < in_samples; cc++)
+			buf[12+cc] = cc;
+
+		*(uint16_t*)(buf+2) = htonl(seq);
+		*(uint32_t*)(buf+4) = htonl(ts);
+
+		seq += 1;
+		ts += in_samples;
+
+		cc += 12; /* include RTP header */
+
+		len = cc;
+
+		do {
+			cont = mgcp_transcoding_process_rtp(endp, &endp->bts_end,
+							    buf, &len, sizeof(buf));
+			if (cont == -EAGAIN) {
+				fprintf(stderr, "Got EAGAIN\n");
+				break;
+			}
+
+			if (cont < 0) {
+				printf("processing failed: %s", strerror(-cont));
+				abort();
+			}
+
+			len -= 12; /* ignore RTP header */
+
+			printf("got %d %s output frames (%d octets) count=%d\n",
+			       len / out_size, dstfmt, len, cont);
+
+			len = cont;
+		} while (len > 0);
+	}
+
+	talloc_free(ctx);
+	return 0;
+}
+
+static const struct log_info_cat log_categories[] = {
+};
+
+const struct log_info log_info = {
+        .cat = log_categories,
+        .num_cat = ARRAY_SIZE(log_categories),
+};
+
+int main(int argc, char **argv)
+{
+	int rc;
+	osmo_init_logging(&log_info);
+
+	printf("=== Transcoding Good Cases ===\n");
+
+	transcode_test("l16", "l16",
+		       (uint8_t *)audio_packets_l16[0].data,
+		       audio_packets_l16[0].len);
+	transcode_test("l16", "gsm",
+		       (uint8_t *)audio_packets_l16[0].data,
+		       audio_packets_l16[0].len);
+	transcode_test("l16", "pcma",
+		       (uint8_t *)audio_packets_l16[0].data,
+		       audio_packets_l16[0].len);
+	transcode_test("gsm", "l16",
+		       (uint8_t *)audio_packets_gsm[0].data,
+		       audio_packets_gsm[0].len);
+	transcode_test("gsm", "gsm",
+		       (uint8_t *)audio_packets_gsm[0].data,
+		       audio_packets_gsm[0].len);
+	transcode_test("gsm", "pcma",
+		       (uint8_t *)audio_packets_gsm[0].data,
+		       audio_packets_gsm[0].len);
+	transcode_test("pcma", "l16",
+		       (uint8_t *)audio_packets_pcma[0].data,
+		       audio_packets_pcma[0].len);
+	transcode_test("pcma", "gsm",
+		       (uint8_t *)audio_packets_pcma[0].data,
+		       audio_packets_pcma[0].len);
+	transcode_test("pcma", "pcma",
+		       (uint8_t *)audio_packets_pcma[0].data,
+		       audio_packets_pcma[0].len);
+
+	printf("=== Transcoding Bad Cases ===\n");
+
+	printf("Invalid size:\n");
+	rc = transcode_test("gsm", "pcma",
+		       (uint8_t *)audio_packets_gsm_invalid_size[0].data,
+		       audio_packets_gsm_invalid_size[0].len);
+	OSMO_ASSERT(rc < 0);
+
+	printf("Invalid data:\n");
+	rc = transcode_test("gsm", "pcma",
+		       (uint8_t *)audio_packets_gsm_invalid_data[0].data,
+		       audio_packets_gsm_invalid_data[0].len);
+	OSMO_ASSERT(rc < 0);
+
+	printf("Invalid payload type:\n");
+	rc = transcode_test("gsm", "pcma",
+		       (uint8_t *)audio_packets_gsm_invalid_ptype[0].data,
+		       audio_packets_gsm_invalid_ptype[0].len);
+	OSMO_ASSERT(rc == 0);
+
+	printf("=== Repacking ===\n");
+
+	test_repacking(160, 160, 0);
+	test_repacking(160, 160, 1);
+	test_repacking(160, 80, 0);
+	test_repacking(160, 80, 1);
+	test_repacking(160, 320, 0);
+	test_repacking(160, 320, 1);
+	test_repacking(160, 240, 0);
+	test_repacking(160, 240, 1);
+	test_repacking(160, 100, 0);
+	test_repacking(160, 100, 1);
+	test_rtp_seq_state();
+	test_transcode_result();
+	test_transcode_change();
+
+	return 0;
+}
+