host: Split transport from slot

In current implementations, we have one interface (with it's own
separate set of USB end-points) per slot.  However, the USB protocol
already includes a slot-number in the header to be able to remove that
restriction in future versions.

Also, if the USB protocol is used remotely over a network, then we could
multiplex differnt slots from different USB interfaces into one stream
on the network side.

In order to prepare the data structures in the host program, let's
introduce that logical split there, too.  Might seem a bit like
overkill, but I don't want to rewrite all code later...

1 files changed, 55 insertions, 26 deletions

diff --git a/host/simtrace2-remsim.c b/host/simtrace2-remsim.c
index 0f1eab6..1f4f5d0 100644
--- a/host/simtrace2-remsim.c
+++ b/host/simtrace2-remsim.c
@@ -49,10 +49,8 @@
 #include <osmocom/sim/class_tables.h>
 #include <osmocom/sim/sim.h>
 
-static struct gsmtap_inst *g_gti;
-
 /* transport to a SIMtrace device */
-static struct st_transport {
+struct st_transport {
 	/* USB */
 	struct libusb_device_handle *usb_devh;
 	struct {
@@ -65,13 +63,27 @@ static struct st_transport {
 	int udp_fd;
 };
 
+/* a SIMtrace slot; communicates over a transport */
+struct st_slot {
+	/* transport through which the slot can be reached */
+	struct st_transport *transp;
+	/* number of the slot within the transport */
+	uint8_t slot_nr;
+};
+
 /* One istance of card emulation */
 struct cardem_inst {
-	struct st_transport transp;
+	/* slot on which this card emulation instance runs */
+	struct st_slot *slot;
+	/* libosmosim SIM card profile */
 	const struct osim_cla_ins_card_profile *card_prof;
+	/* libosmosim SIM card channel */
 	struct osim_chan_hdl *chan;
 };
 
+/* global GSMTAP instance */
+static struct gsmtap_inst *g_gti;
+
 static int gsmtap_send_sim(const uint8_t *apdu, unsigned int len)
 {
 	struct gsmtap_hdr *gh;
@@ -105,6 +117,7 @@ static int gsmtap_send_sim(const uint8_t *apdu, unsigned int len)
  * SIMTRACE pcore protocol
  ***********************************************************************/
 
+/*! \brief allocate a message buffer for simtrace use */
 static struct msgb *st_msgb_alloc(void)
 {
 	return msgb_alloc_headroom(1024+32, 32, "SIMtrace");
@@ -119,7 +132,7 @@ static void apdu_out_cb(uint8_t *buf, unsigned int len, void *user_data)
 #endif
 
 /*! \brief Transmit a given command to the SIMtrace2 device */
-static int st_transp_tx_msg(struct st_transport *transp, struct msgb *msg)
+int st_transp_tx_msg(struct st_transport *transp, struct msgb *msg)
 {
 	int rc;
 
@@ -139,16 +152,33 @@ static int st_transp_tx_msg(struct st_transport *transp, struct msgb *msg)
 	return rc;
 }
 
-static struct simtrace_msg_hdr *st_push_hdr(struct msgb *msg, uint8_t msg_class, uint8_t msg_type)
+static struct simtrace_msg_hdr *st_push_hdr(struct msgb *msg, uint8_t msg_class, uint8_t msg_type,
+					    uint8_t slot_nr)
 {
 	struct simtrace_msg_hdr *sh = msgb_push(msg, sizeof(*sh));
 
 	memset(sh, 0, sizeof(*sh));
 	sh->msg_class = msg_class;
 	sh->msg_type = msg_type;
+	sh->slot_nr = slot_nr;
 	sh->msg_len = msgb_length(msg);
 }
 
+/* transmit a given message to a specified slot. Expects all headers
+ * present before calling the function */
+int st_slot_tx_msg(struct st_slot *slot, struct msgb *msg,
+		   uint8_t msg_class, uint8_t msg_type)
+{
+	struct simtrace_msg_hdr *sh = msg->data;
+
+	sh->slot_nr = slot->slot_nr;
+
+	st_push_hdr(msg, msg_class, msg_type, slot->slot_nr);
+
+	return st_transp_tx_msg(slot->transp, msg);
+}
+
+
 /***********************************************************************
  * Card Emulation protocol
  ***********************************************************************/
@@ -165,9 +195,7 @@ static int cardem_request_card_insert(struct cardem_inst *ci, bool inserted)
 	if (inserted)
 		cins->card_insert = 1;
 
-	st_push_hdr(msg, SIMTRACE_MSGC_CARDEM, SIMTRACE_MSGT_DT_CEMU_CARDINSERT);
-
-	return st_transp_tx_msg(&ci->transp, msg);
+	return st_slot_tx_msg(ci->slot, msg, SIMTRACE_MSGC_CARDEM, SIMTRACE_MSGT_DT_CEMU_CARDINSERT);
 }
 
 /*! \brief Request the SIMtrace2 to transmit a Procedure Byte, then Rx */
@@ -185,9 +213,7 @@ static int cardem_request_pb_and_rx(struct cardem_inst *ci, uint8_t pb, uint8_t
 	/* one data byte */
 	msgb_put_u8(msg, pb);
 
-	st_push_hdr(msg, SIMTRACE_MSGC_CARDEM, SIMTRACE_MSGT_DT_CEMU_TX_DATA);
-
-	return st_transp_tx_msg(&ci->transp, msg);
+	return st_slot_tx_msg(ci->slot, msg, SIMTRACE_MSGC_CARDEM, SIMTRACE_MSGT_DT_CEMU_TX_DATA);
 }
 
 /*! \brief Request the SIMtrace2 to transmit a Procedure Byte, then Tx */
@@ -212,9 +238,7 @@ static int cardem_request_pb_and_tx(struct cardem_inst *ci, uint8_t pb,
 	cur = msgb_put(msg, data_len_in);
 	memcpy(cur, data, data_len_in);
 
-	st_push_hdr(msg, SIMTRACE_MSGC_CARDEM, SIMTRACE_MSGT_DT_CEMU_TX_DATA);
-
-	return st_transp_tx_msg(&ci->transp, msg);
+	return st_slot_tx_msg(ci->slot, msg, SIMTRACE_MSGC_CARDEM, SIMTRACE_MSGT_DT_CEMU_TX_DATA);
 }
 
 /*! \brief Request the SIMtrace2 to send a Status Word */
@@ -235,9 +259,7 @@ static int cardem_request_sw_tx(struct cardem_inst *ci, const uint8_t *sw)
 	cur[0] = sw[0];
 	cur[1] = sw[1];
 
-	st_push_hdr(msg, SIMTRACE_MSGC_CARDEM, SIMTRACE_MSGT_DT_CEMU_TX_DATA);
-
-	return st_transp_tx_msg(&ci->transp, msg);
+	return st_slot_tx_msg(ci->slot, msg, SIMTRACE_MSGC_CARDEM, SIMTRACE_MSGT_DT_CEMU_TX_DATA);
 }
 
 static void atr_update_csum(uint8_t *atr, unsigned int atr_len)
@@ -266,12 +288,9 @@ static int cardem_request_set_atr(struct cardem_inst *ci, const uint8_t *atr, un
 	cur = msgb_put(msg, atr_len);
 	memcpy(cur, atr, atr_len);
 
-	st_push_hdr(msg, SIMTRACE_MSGC_CARDEM, SIMTRACE_MSGT_DT_CEMU_SET_ATR);
-
-	return st_transp_tx_msg(&ci->transp, msg);
+	return st_slot_tx_msg(ci->slot, msg, SIMTRACE_MSGC_CARDEM, SIMTRACE_MSGT_DT_CEMU_SET_ATR);
 }
 
-
 /***********************************************************************
  * Incoming Messages
  ***********************************************************************/
@@ -439,7 +458,7 @@ static const struct option opts[] = {
 
 static void run_mainloop(struct cardem_inst *ci)
 {
-	struct st_transport *transp = &ci->transp;
+	struct st_transport *transp = ci->slot->transp;
 	unsigned int msg_count, byte_count = 0;
 	uint8_t buf[16*265];
 	int xfer_len;
@@ -474,7 +493,18 @@ static void run_mainloop(struct cardem_inst *ci)
 	}
 }
 
-struct cardem_inst _ci, *ci = &_ci;
+static struct st_transport _transp;
+
+static struct st_slot _slot = {
+	.transp = &_transp,
+	.slot_nr = 0,
+};
+
+struct cardem_inst _ci = {
+	.slot = &_slot,
+};
+
+struct cardem_inst *ci = &_ci;
 
 static void signal_handler(int signal)
 {
@@ -490,7 +520,7 @@ static void signal_handler(int signal)
 
 int main(int argc, char **argv)
 {
-	struct st_transport *transp = &ci->transp;
+	struct st_transport *transp = ci->slot->transp;
 	char *gsmtap_host = "127.0.0.1";
 	int rc;
 	int c, ret = 1;
@@ -557,7 +587,6 @@ int main(int argc, char **argv)
 		goto do_exit;
 	}
 
-	memset(ci, 0, sizeof(*ci));
 	transp->udp_fd = -1;
 
 	ci->card_prof = &osim_uicc_sim_cic_profile;