bankd: Add GSMTAP functionality for SIM traffic

If a --gsmtap-host (-g) address is specified on the command line, trace
SIM ATRs and APDUs to the given IP. If --gsmtap-slot (-G) is provided,
limit tracing to the specified bank slot number. This feature may be
useful when diagnosing issues with the remote SIM framework.

Added new log category: DGSMTAP

Also, cleaned up alignment in bankd --help output and removed unused -o option.

Change-Id: I05b599858d8758633aa56c3f12f258c27cf42d08

src/bankd/Makefile.am

@@ -3,7 +3,7 @@ AM_CFLAGS = -Wall -I$(top_srcdir)/include -I$(top_builddir)/include -I$(top_srcd
 	    $(OSMOCORE_CFLAGS) $(OSMOGSM_CFLAGS) $(OSMOABIS_CFLAGS) \
 	    $(PCSC_CFLAGS)
 
-noinst_HEADERS = bankd.h internal.h
+noinst_HEADERS = bankd.h internal.h gsmtap.h
 
 bin_PROGRAMS = osmo-remsim-bankd
 noinst_PROGRAMS = pcsc_test
@@ -13,7 +13,7 @@ pcsc_test_LDADD = $(OSMOCORE_LIBS) \
 		  $(PCSC_LIBS) $(top_builddir)/src/libosmo-rspro.la
 
 osmo_remsim_bankd_SOURCES = ../slotmap.c ../rspro_client_fsm.c ../debug.c \
-			  bankd_main.c bankd_pcsc.c
+			  bankd_main.c bankd_pcsc.c gsmtap.c
 osmo_remsim_bankd_LDADD = $(OSMOCORE_LIBS) $(OSMOGSM_LIBS) $(OSMOABIS_LIBS) \
 			  $(PCSC_LIBS) $(CSV_LIBS) $(top_builddir)/src/libosmo-rspro.la
 

src/bankd/bankd.h

@@ -139,6 +139,8 @@ struct bankd {
 
 	struct {
 		bool permit_shared_pcsc;
+		char *gsmtap_host;
+		int gsmtap_slot;
 	} cfg;
 };
 

src/bankd/bankd_main.c

@@ -47,6 +47,7 @@
 #include "rspro_client_fsm.h"
 #include "debug.h"
 #include "rspro_util.h"
+#include "gsmtap.h"
 
 /* signal indicates to worker thread that its map has been deleted */
 #define SIGMAPDEL	SIGRTMIN+1
@@ -100,6 +101,8 @@ static void bankd_init(struct bankd *bankd)
 	INIT_LLIST_HEAD(&bankd->pcsc_slot_names);
 
 	bankd->cfg.permit_shared_pcsc = false;
+	bankd->cfg.gsmtap_host = NULL;
+	bankd->cfg.gsmtap_slot = -1;
 }
 
 /* create + start a new bankd_worker thread */
@@ -284,18 +287,20 @@ send_resp:
 static void printf_help()
 {
 	printf(
-"  -h --help			Print this help message\n"
-"  -V --version			Print the version of the program\n"
-"  -d --debug option		Enable debug logging (e.g. DMAIN:DST2)\n"
-"  -i --server-host A.B.C.D	remsim-server IP address (default: 127.0.0.1)\n"
-"  -p --server-port <1-65535>	remsim-server TCP port (default: 9998)\n"
-"  -b --bank-id <1-1023>	Bank Identifier of this SIM bank (default: 1)\n"
-"  -n --num-slots <1-1023>	Number of Slots in this SIM bank (default: 8)\n"
-"  -I --bind-ip A.B.C.D		Local IP address to bind for incoming client\n"
-"				connections (default: INADDR_ANY)\n"
-"  -P --bind-port <1-65535>	Local TCP port to bind for incoming client\n"
-"				connectionss (default: 9999)\n"
-"  -s --permit-shared-pcsc	Permit SHARED access to PC/SC readers (default: exclusive)\n"
+"  -h --help                    Print this help message\n"
+"  -V --version                 Print the version of the program\n"
+"  -d --debug option            Enable debug logging (e.g. DMAIN:DST2)\n"
+"  -i --server-host A.B.C.D     remsim-server IP address (default: 127.0.0.1)\n"
+"  -p --server-port <1-65535>   remsim-server TCP port (default: 9998)\n"
+"  -b --bank-id <1-1023>        Bank Identifier of this SIM bank (default: 1)\n"
+"  -n --num-slots <1-1023>      Number of Slots in this SIM bank (default: 8)\n"
+"  -I --bind-ip A.B.C.D         Local IP address to bind for incoming client\n"
+"                               connections (default: INADDR_ANY)\n"
+"  -P --bind-port <1-65535>		Local TCP port to bind for incoming client\n"
+"                               connections (default: 9999)\n"
+"  -s --permit-shared-pcsc      Permit SHARED access to PC/SC readers (default: exclusive)\n"
+"  -g --gsmtap-ip A.B.C.D       Enable GSMTAP and send APDU traces to given IP\n"
+"  -G --gsmtap-slot <0-1023>    Limit tracing to given bank slot, only (default: all slots)\n"
 	      );
 }
 
@@ -318,10 +323,12 @@ static void handle_options(int argc, char **argv)
 			{ "bind-ip", 1, 0, 'I' },
 			{ "bind-port", 1, 0, 'P' },
 			{ "permit-shared-pcsc", 0, 0, 's' },
+			{ "gsmtap-ip", 1, 0, 'g' },
+			{ "gsmtap-slot", 1, 0, 'G' },
 			{ 0, 0, 0, 0 }
 		};
 
-		c = getopt_long(argc, argv, "hVd:i:p:o:b:n:N:I:P:s", long_options, &option_index);
+		c = getopt_long(argc, argv, "hVd:i:p:b:n:N:I:P:sg:G:", long_options, &option_index);
 		if (c == -1)
 			break;
 
@@ -361,6 +368,12 @@ static void handle_options(int argc, char **argv)
 		case 's':
 			g_bankd->cfg.permit_shared_pcsc = true;
 			break;
+		case 'g':
+			g_bankd->cfg.gsmtap_host = optarg;
+			break;
+		case 'G':
+			g_bankd->cfg.gsmtap_slot = atoi(optarg);
+			break;
 		}
 	}
 }
@@ -418,6 +431,15 @@ int main(int argc, char **argv)
 	}
 	g_bankd->accept_fd = rc;
 
+	/* initialize gsmtap, if required */
+	if (g_bankd->cfg.gsmtap_host) {
+		rc = bankd_gsmtap_init(g_bankd->cfg.gsmtap_host);
+		if (rc < 0) {
+			fprintf(stderr, "Unable to open GSMTAP");
+			exit(1);
+		}
+	}
+
 	/* create worker threads: One per reader/slot! */
 	for (i = 0; i < g_bankd->srvc.bankd.num_slots; i++) {
 		struct bankd_worker *w;
@@ -661,6 +683,14 @@ static int worker_send_atr(struct bankd_worker *worker)
 	set_atr = rspro_gen_SetAtrReq(worker->client.clslot.client_id,
 				      worker->client.clslot.slot_nr,
 				      worker->card.atr, worker->card.atr_len);
+
+	/* trace ATR to GSMTAP, if configured */
+	if (g_bankd->cfg.gsmtap_host && (g_bankd->cfg.gsmtap_slot == -1 ||
+		g_bankd->cfg.gsmtap_slot == worker->slot.slot_nr)) {
+		bankd_gsmtap_send_apdu(GSMTAP_SIM_ATR, worker->card.atr, worker->card.atr_len,
+			NULL, 0);
+	}
+
 	if (!set_atr)
 		return -1;
 	return worker_send_rspro(worker, set_atr);
@@ -761,6 +791,12 @@ static int worker_handle_tpduModemToCard(struct bankd_worker *worker, const Rspr
 					    rx_buf, rx_buf_len);
 	worker_send_rspro(worker, pdu_resp);
 
+	/* trace APDU to GSMTAP, if configured */
+	if (g_bankd->cfg.gsmtap_host && (g_bankd->cfg.gsmtap_slot == -1 ||
+		g_bankd->cfg.gsmtap_slot == worker->slot.slot_nr)) {
+		bankd_gsmtap_send_apdu(GSMTAP_SIM_APDU, mdm2sim->data.buf, mdm2sim->data.size, rx_buf,
+			rx_buf_len);
+	}
 	return 0;
 }
 

src/bankd/gsmtap.c

@@ -0,0 +1,109 @@
+/* gsmtap - How to encapsulate SIM protocol traces in GSMTAP
+ *
+ * (C) 2016-2019 by Harald Welte <hwelte@hmw-consulting.de>
+ *
+ * This program 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 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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.
+ */
+
+/* among other things, bring in GNU-specific strerror_r() */
+#define _GNU_SOURCE
+
+#include <osmocom/core/gsmtap.h>
+#include <osmocom/core/gsmtap_util.h>
+#include <osmocom/core/logging.h>
+
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/uio.h>
+
+#include "debug.h"
+
+/*! global GSMTAP instance */
+static struct gsmtap_inst *g_gti;
+
+/*! initialize the global GSMTAP instance for SIM traces
+ *
+ * \param[in] gsmtap_host Hostname to send GSMTAP packets
+ *
+ * \return 0 on success, non-zero on error
+ */
+int bankd_gsmtap_init(const char *gsmtap_host)
+{
+	if (g_gti)
+		return -EEXIST;
+
+	errno = 0;
+	g_gti = gsmtap_source_init(gsmtap_host, GSMTAP_UDP_PORT, 0);
+	if (!g_gti) {
+		LOGP(DGSMTAP, LOGL_ERROR, "unable to initialize GSMTAP\n");
+		return -EIO;
+	}
+	gsmtap_source_add_sink(g_gti);
+
+	LOGP(DGSMTAP, LOGL_INFO, "initialized GSMTAP to %s\n", gsmtap_host);
+
+	return 0;
+}
+
+/*! Log one APDU via the global GSMTAP instance by concatenating mdm_tpdu and sim_tpdu.
+ *
+ *  \param[in] sub_type     GSMTAP sub-type (GSMTAP_SIM_* constant)
+ *  \param[in] mdm_tpdu     User-provided buffer with ModemToCard TPDU to log. May be NULL.
+ *  \param[in] mdm_tpdu_len Length of ModemToCard TPDU, in bytes.
+ *  \param[in] sim_tpdu     User-provided buffer with CardToModem TPDU to log. May be NULL.
+ *  \param[in] sim_tpdu_len Length of CardToModem TPDU, in bytes.
+ *
+ *  \return number of bytes sent on success, -1 on failure
+ */
+int bankd_gsmtap_send_apdu(uint8_t sub_type, const uint8_t *mdm_tpdu, unsigned int mdm_tpdu_len,
+	const uint8_t *sim_tpdu, unsigned int sim_tpdu_len)
+{
+	const struct gsmtap_hdr gh = {
+		.version = GSMTAP_VERSION,
+		.hdr_len = sizeof(struct gsmtap_hdr)/4,
+		.type = GSMTAP_TYPE_SIM,
+		.sub_type = sub_type,
+	};
+
+	struct iovec iov[3];
+	unsigned int cnt = 0;
+
+	iov[cnt].iov_base = (void *)&gh;
+	iov[cnt].iov_len = sizeof(gh);
+	cnt++;
+
+	if (mdm_tpdu && mdm_tpdu_len) {
+		iov[cnt].iov_base = (void *)mdm_tpdu;
+		iov[cnt].iov_len = mdm_tpdu_len;
+		cnt++;
+	}
+
+	if (sim_tpdu && sim_tpdu_len) {
+		iov[cnt].iov_base = (void *)sim_tpdu;
+		iov[cnt].iov_len = sim_tpdu_len;
+		cnt++;
+	}
+
+	LOGP(DGSMTAP, LOGL_DEBUG, "sending APDU sub_type=%u, mdm_tpdu len=%u, sim_tpdu len=%u, iov cnt=%u\n",
+		sub_type, mdm_tpdu_len, sim_tpdu_len, cnt);
+
+	const int rc = writev(gsmtap_inst_fd(g_gti), iov, cnt);
+	if (rc < 0) {
+		char errtxt[128];
+		LOGP(DGSMTAP, LOGL_ERROR, "writev() failed with errno=%d: %s\n", errno, strerror_r(errno,
+			errtxt, sizeof(errtxt)));
+		return rc;
+	}
+
+	return 0;
+}

src/bankd/gsmtap.h

@@ -0,0 +1,7 @@
+#pragma once
+#include <stdint.h>
+#include <osmocom/core/gsmtap.h>
+
+int bankd_gsmtap_init(const char *gsmtap_host);
+int bankd_gsmtap_send_apdu(uint8_t sub_type, const uint8_t *mdm_tpdu, unsigned int mdm_tpdu_len,
+	const uint8_t *sim_tpdu, unsigned int sim_tpdu_len);

src/debug.c

@@ -52,6 +52,11 @@ static const struct log_info_cat default_categories[] = {
 		.loglevel = LOGL_INFO,
 		.enabled = 1,
 	},
+	[DGSMTAP] = {
+		.name = "DGSMTAP",
+		.loglevel = LOGL_INFO,
+		.enabled = 1,
+	},
 };
 
 const struct log_info log_info = {

src/debug.h

@@ -8,6 +8,7 @@ enum {
 	DREST,
 	DSLOTMAP,
 	DBANKDW,
+	DGSMTAP,
 };
 
 extern const struct log_info log_info;