initial import of incomplete project to record E1 lines

README

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+Osmocom E1 recorder
+===================
+(C) 2016 by Harald Welte <laforge@gnumonks.org>
+
+The idea of this program is to be able to passively record E1/T1 based
+communications for purposes of data analysis.
+
+Recording of a single E1 link always requires two E1 interface cards,
+one for each direction.
+
+Recording can be performed either
+* passively, using a E1 Tap aapter
+* asa proxy / man-in-the-middle
+
+All timeslots will be opened in "raw" mode, making sure the recording
+will work wheter or not there is HLDC-based signalling (MTP or LAPD),
+PCM voice, TRAU frames or anything else on the line.
+
+Recording will be done on a per-timeslot basis, dumping the raw bytes
+read for this timeslot into a file.
+
+New files are started regularly, after reaching a pre-determined file
+size limit.  File names contain RTC time stamping and timeslot number.
+
+Later possible extensions could include automatic detection of the
+payload and a more intelligent storage format (e.g. in case of HDLC
+bsaed signalling).

src/Makefile

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+CFLAGS=-g -Wall
+LDFLAGS=-losmocore -losmogsm -losmovty -losmoabis -ltalloc
+
+all: osmo-e1-recorder
+
+osmo-e1-recorder: e1_recorder.o storage.o vty.o
+	$(CC) $(LDFLAGS) -o$@ $^
+
+%.o: %.c
+	$(CC) $(CFLAGS) -o $@ -c $^
+
+clean:
+	@rm *.o osmo-e1-recorder

src/e1_recorder.c

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+#include <osmocom/core/signal.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/application.h>
+#include <osmocom/vty/vty.h>
+#include <osmocom/vty/telnet_interface.h>
+
+#include <osmocom/abis/abis.h>
+#include <osmocom/abis/e1_input.h>
+
+#include "storage.h"
+#include "recorder.h"
+
+static enum osmo_e1cap_capture_mode ts2cap_mode(struct e1inp_ts *ts)
+{
+	switch (ts->type) {
+	case E1INP_TS_TYPE_RAW:
+		return OSMO_E1CAP_MODE_RAW;
+	case E1INP_TS_TYPE_SIGN:
+		return OSMO_E1CAP_MODE_HDLC;
+	case E1INP_TS_TYPE_TRAU:
+		return OSMO_E1CAP_MODE_TRAU;
+	default:
+		OSMO_ASSERT(0);
+	}
+}
+
+/* receive a raw message frome the E1 timeslot */
+void e1ts_raw_recv(struct e1inp_ts *ts, struct msgb *msg)
+{
+	struct e1_recorder_line *rline = &g_recorder.line[ts->line->nr];
+	enum osmo_e1cap_capture_mode cap_mode = ts2cap_mode(ts);
+
+	/* FIXME: special processing of TFP and PGSL */
+
+	e1frame_store(ts, msg, cap_mode);
+
+	if (rline.mirror.enabled) {
+		/* forward data to destination line */
+	}
+}
+
+static int inp_sig_cb(unsigned int subsys, unsigned int signal,
+		      void *handler_data, void *signal_data)
+{
+	OSMO_ASSERT(subsys == SS_L_INPUT);
+
+	/* FIXME */
+
+	return 0;
+}
+
+//	e1inp_ts_config_raw(ts, line, &e1ts_raw_recv);
+
+static const struct log_info_cat recorder_categories[] = {
+	[DMAIN] = {
+		.name = "MAIN",
+		.enabled = 1, .loglevel = LOGL_DEBUG,
+	},
+};
+static struct log_info info = {
+	.cat = recorder_categories,
+	.num_cat = ARRAY_SIZE(recorder_categories),
+};
+
+struct vty_app_info vty_info = {
+	.name = "osmo-e1-recorder",
+	.version = "0",
+	.copyright = "(C) 2016 by Harald Welte <laforge@gnumonks.org>\n",
+};
+
+static void *rec_tall_ctx;
+struct e1_recorder g_recorder;
+
+int main(int argc, char **argv)
+{
+	int rc;
+
+	rec_tall_ctx = talloc_named_const(NULL, 0, "recorder");
+
+	osmo_init_logging(&info);
+	vty_init(&vty_info);
+	osmo_signal_register_handler(SS_L_INPUT, inp_sig_cb, NULL);
+	libosmo_abis_init(rec_tall_ctx);
+	e1inp_vty_init();
+	recorder_vty_init();
+
+	rc = vty_read_config_file("osmo-e1-recorder.cfg", NULL);
+	if (rc < 0)
+		exit(1);
+
+	/* start telne tafte reading config for vty_get_bind_adr() */
+	telnet_init_dynif(rec_tall_ctx, NULL, vty_get_bind_addr(), 4444);
+
+	while (1) {
+		osmo_select_main(0);
+	};
+}

src/recorder.h

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+#pragma once
+#include <stdbool.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/vty/command.h>
+#include <osmocom/abis/e1_input.h>
+
+/* logging */
+enum {
+	DMAIN,
+};
+
+/* vty */
+enum rec_vty_node {
+	RECORDER_NODE = _LAST_OSMOVTY_NODE + 1,
+};
+
+struct e1_recorder_line {
+	struct {
+		bool enabled;
+		uint8_t line_nr;
+	} mirror;
+};
+
+struct e1_recorder {
+	char *storage_path;
+	unsigned int max_file_size_mb;
+	struct e1_recorder_line line[256];
+};
+
+extern struct e1_recorder g_recorder;
+
+/* e1_recorder.c */
+void e1ts_raw_recv(struct e1inp_ts *ts, struct msgb *msg);
+
+/* vty.c */
+void recorder_vty_init(void);

src/storage.c

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+#include <osmocom/core/msgb.h>
+#include <osmocom/abis/e1_input.h>
+
+#include "storage.h"
+
+int e1frame_store(struct e1inp_ts *ts, struct msgb *msg, enum osmo_e1cap_capture_mode mode)
+{
+	struct osmo_e1cap_pkthdr *h;
+	uint32_t len = msg->len;
+
+	h = (struct osmo_e1cap_pkthdr *) msgb_push(msg, sizeof(*h));
+	h->len = htonl(len);
+	h->line_nr = ts->line->num;
+	h->ts_nr = ts->num;
+	h->capture_mode = mode;
+	h->flags = 0;
+
+	/* FIXME: Write */
+	return 0;
+}

src/storage.h

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+#pragma once
+#include <stdint.h>
+
+enum osmo_e1cap_capture_mode {
+	OSMO_E1CAP_MODE_RAW,
+	OSMO_E1CAP_MODE_HDLC,
+	OSMO_E1CAP_MODE_TRAU,
+	OSMO_E1CAP_MODE_PGSL,
+};
+
+/* header for each frame we store */
+struct osmo_e1cap_pkthdr {
+	struct timeval ts;
+	uint32_t len;
+	uint8_t line_nr;
+	uint8_t ts_nr;
+	uint8_t capture_mode;
+	uint8_t flags;
+} __attribute__((aligned));
+
+int e1frame_store(struct e1inp_ts *ts, struct msgb *msg, enum osmo_e1cap_capture_mode mode);

src/vty.c

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+
+#include <osmocom/abis/e1_input.h>
+#include <osmocom/vty/command.h>
+#include <osmocom/vty/vty.h>
+
+#include "recorder.h"
+
+#define LINE_STR "Configure Recording for given Line\nE1/T1 Line Number\n"
+
+DEFUN(cfg_recorder, cfg_recorder_cmd,
+	"recorder",
+	"Configuration of E1 Recorder\n")
+{
+	vty->node = RECORDER_NODE;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_rec_line_ts_mode, cfg_rec_line_ts_mode_cmd,
+	"line <0-255> ts <0-31> mode (none|signalling|trau|raw)",
+	LINE_STR
+	"E1/T1 Timeslot Number\n"
+	"E1/T1 Timeslot Number\n"
+	"Recording Mode\n"
+	"No recording\n"
+	"Signalling Data (HDLC)\n"
+	"TRAU Frames\n"
+	"Raw Data\n")
+{
+	int line_nr = atoi(argv[0]);
+	int ts_nr = atoi(argv[1]);
+	int mode = get_string_value(e1inp_ts_type_names, argv[2]);
+	struct e1inp_line *line;
+	struct e1inp_ts *ts;
+
+	if (mode < 0) {
+		vty_out(vty, "Cannot parse mode %s%s", argv[2], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+
+	line = e1inp_line_find(line_nr);
+	if (!line) {
+		vty_out(vty, "Cannot find line %d%s", line_nr, VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+	if (ts_nr >= line->num_ts) {
+		vty_out(vty, "Timeslot %d is too large%s", ts_nr, VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+	ts = &line->ts[ts_nr];
+
+	switch (mode) {
+	case E1INP_TS_TYPE_NONE:
+		/* TOOD: have eqinp_ts_config_none ? */
+		ts->type = E1INP_TS_TYPE_NONE;
+		break;
+	case E1INP_TS_TYPE_SIGN:
+		e1inp_ts_config_sign(ts, line);
+		break;
+	case E1INP_TS_TYPE_RAW:
+		e1inp_ts_config_raw(ts, line, &e1ts_raw_recv);
+		break;
+	}
+
+	/* notify driver of change */
+	e1inp_line_update(line);
+
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_rec_line_mirror, cfg_rec_line_mirror_cmd,
+	"line <0-255> mirror <0-255>",
+	LINE_STR "Mirror this line to another line\n"
+	"E1/T1 Line Number\n")
+{
+	uint8_t line_nr = atoi(argv[0]);
+	uint8_t peer_nr = atoi(argv[1]);
+	struct e1_recorder_line *line = &g_recorder.line[line_nr];
+	struct e1_recorder_line *peer = &g_recorder.line[peer_nr];
+	/* look up morror peer and enable mirror flag on peer */
+	if (peer->mirror.enabled &&
+	    peer->mirror.line_nr != line_nr) {
+		vty_out(vty, "Peer line %u already part of another mirror%s",
+			peer_nr, VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+	peer->mirror.enabled = true;
+	peer->mirror.line_nr = line_nr;
+	/* enable mirror flag of current line */
+	if (line->mirror.enabled &&
+	    line->mirror.line_nr != peer_nr) {
+		vty_out(vty, "Line %u already part of another mirror%s",
+			line_nr, VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+	line->mirror.enabled = true;
+	line->mirror.line_nr = peer_nr;
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_rec_no_line_mirror, cfg_rec_no_line_mirror_cmd,
+	"no line <0-255> mirror",
+	LINE_STR "Mirror this line to another line\n"
+	"E1/T1 Line Number\n")
+{
+	uint8_t line_nr = atoi(argv[0]);
+	struct e1_recorder_line *line = &g_recorder.line[line_nr];
+	struct e1_recorder_line *peer;
+
+	if (!line->mirror.enabled)
+		return CMD_WARNING;
+	/* look up morror peer (if any) and disable mirror flag on peer */
+	peer = &g_recorder.line[line->mirror.line_nr];
+	if (peer->mirror.enabled) {
+		peer->mirror.enabled = false;
+		peer->mirror.line_nr = 0;
+	}
+	/* dsiable mirror flag of current line */
+	if (line->mirror.enabled){
+		line->mirror.enabled = false;
+		line->mirror.line_nr = 0;
+	}
+	return CMD_SUCCESS;
+}
+
+
+DEFUN(cfg_rec_save_path, cfg_rec_save_path_cmd,
+	"storage-path PATH",
+	"Configure the directory for storing recordings\n"
+	"Directory to which recordings are stored\n")
+{
+	osmo_talloc_replace_string(NULL, &g_recorder.storage_path, argv[0]);
+	return CMD_SUCCESS;
+}
+
+DEFUN(cfg_rec_file_size, cfg_rec_file_size_cmd,
+	"file-size-mb <1-9999999>",
+	"Configure the maximum file size before starting new file\n"
+	"Megabytes\n")
+{
+	g_recorder.max_file_size_mb = atoi(argv[0]);
+	return CMD_SUCCESS;
+}
+
+static void config_write_recorder_line(struct vty *vty, unsigned int lnr)
+{
+	struct e1inp_line *line = e1inp_line_find(lnr);
+	struct e1_recorder_line *rline = &g_recorder.line[lnr];
+	unsigned int i;
+
+	if (rline->mirror.enabled) {
+		vty_out(vty, " line %u mirror %u%s",
+			lnr, rline->mirror.line_nr, VTY_NEWLINE);
+	}
+
+	if (!line)
+		return;
+
+	for (i = 0; i < line->num_ts; i++) {
+		struct e1inp_ts *ts = &line->ts[i];
+	}
+}
+
+static int config_write_recorder(struct vty *vty)
+{
+	unsigned int i;
+
+	vty_out(vty, "recorder%s", VTY_NEWLINE);
+	vty_out(vty, " file-size-mb %u%s", g_recorder.max_file_size_mb,
+		VTY_NEWLINE);
+	vty_out(vty, " storage-path %s%s", g_recorder.storage_path,
+		VTY_NEWLINE);
+	for (i = 0; i < 255; i++) {
+		config_write_recorder_line(vty, i);
+	}
+
+	return 0;
+}
+
+static struct cmd_node cfg_recorder_node = {
+	RECORDER_NODE,
+	"%s(config-recorder)# ",
+	1,
+};
+
+void recorder_vty_init(void)
+{
+	install_element(CONFIG_NODE, &cfg_recorder_cmd);
+
+	install_node(&cfg_recorder_node, config_write_recorder);
+	install_element(RECORDER_NODE, &cfg_rec_line_ts_mode_cmd);
+	install_element(RECORDER_NODE, &cfg_rec_line_mirror_cmd);
+	install_element(RECORDER_NODE, &cfg_rec_no_line_mirror_cmd);
+	install_element(RECORDER_NODE, &cfg_rec_save_path_cmd);
+	install_element(RECORDER_NODE, &cfg_rec_file_size_cmd);
+}