iuup: Rework API to support RFCI IDs != RFCI index

The initially merged IuUP API and implementation assumed that RFCI with
ID was always in the position of its ID inside the list of RFCIs. This
was the case for messages sent by ip.access nano3g as well as our own
osmocom implementation. However it was noticed that other nodes from
other vendors actually use other order, as allowed by the IuUP message
format.
Hence, we need to break the assumption and provide explicit ID
information in the list.

NOTICE: This commit breaks API and ABI compatibility with older versions
of libosmogsm, but not with any previous release of libosmocore since
the API is only available in master so far (it was added in
9fe1f9fb0b3197cdecaa55017d3afd7355e59c36).
Similary, it's only user (osmo-mgw) only uses the API in master, so
there's no API breakage with older releases.

Related: SYS#5969
Change-Id: Ib21cee2e30bf83dff4e167f79541796007af9845

1 files changed, 60 insertions, 39 deletions

diff --git a/src/gsm/iuup.c b/src/gsm/iuup.c
index eb595ce5..edcea3b4 100644
--- a/src/gsm/iuup.c
+++ b/src/gsm/iuup.c
@@ -286,13 +286,10 @@ static struct osmo_iuup_tnl_prim *tnp_ctrl_init_alloc(struct osmo_iuup_instance
 	struct iuup_ctrl_init_rfci_hdr *ihdr_rfci;
 	struct iuup_ctrl_init_tail *itail;
 	unsigned int i, j;
-	uint8_t num_subflows, num_rfci;
 	uint16_t payload_crc;
+	uint8_t rfci_cnt;
 	struct msgb *msg;
 
-	num_subflows = iui->config.num_subflows;
-	num_rfci = iui->config.num_rfci;
-
 	itp = osmo_iuup_tnl_prim_alloc(iui, OSMO_IUUP_TNL_UNITDATA, PRIM_OP_REQUEST, IUUP_MSGB_SIZE);
 	msg = itp->oph.msg;
 
@@ -307,42 +304,68 @@ static struct osmo_iuup_tnl_prim *tnp_ctrl_init_alloc(struct osmo_iuup_instance
 
 	ihdr = (struct iuup_ctrl_init_hdr *)msgb_put(msg, sizeof(*ihdr));
 	ihdr->chain_ind = 0; /* this frame is the last frame for the procedure. TODO: support several */
-	ihdr->num_subflows_per_rfci = num_subflows;
+	ihdr->num_subflows_per_rfci = iui->config.num_subflows;
 	ihdr->ti = iui->config.IPTIs_present ? 1 : 0;
 	ihdr->spare = 0;
 
 	/* RFCI + subflow size part: */
-	for (i = 0; i < num_rfci; i++) {
-		bool last = (i+1 == num_rfci);
-		uint8_t len_size = 1;
-		for (j = 0; j < num_subflows; j++) {
-			if (iui->config.subflow_sizes[i][j] > UINT8_MAX)
+	rfci_cnt = 0;
+	for (i = 0; i < ARRAY_SIZE(iui->config.rfci); i++) {
+		bool last;
+		uint8_t len_size;
+		struct osmo_iuup_rfci *rfci = &iui->config.rfci[i];
+		if (!rfci->used)
+			continue;
+		rfci_cnt++;
+		last = (rfci_cnt == iui->config.num_rfci);
+
+		len_size = 1;
+		for (j = 0; j < iui->config.num_subflows; j++) {
+			if (rfci->subflow_sizes[j] > UINT8_MAX)
 				len_size = 2;
 		}
-		ihdr_rfci = (struct iuup_ctrl_init_rfci_hdr *)msgb_put(msg, sizeof(*ihdr_rfci) + len_size * num_subflows);
-		ihdr_rfci->rfci = i;
+
+		ihdr_rfci = (struct iuup_ctrl_init_rfci_hdr *)msgb_put(msg, sizeof(*ihdr_rfci) + len_size * iui->config.num_subflows);
+		ihdr_rfci->rfci = rfci->id;
 		ihdr_rfci->li = len_size - 1;
 		ihdr_rfci->lri = last;
 		if (len_size == 2) {
 			uint16_t *buf = (uint16_t *)&ihdr_rfci->subflow_length[0];
-			for (j = 0; j < num_subflows; j++)
-				osmo_store16be(iui->config.subflow_sizes[i][j], buf++);
+			for (j = 0; j < iui->config.num_subflows; j++)
+				osmo_store16be(rfci->subflow_sizes[j], buf++);
 		} else {
-			for (j = 0; j < num_subflows; j++)
-				ihdr_rfci->subflow_length[j] = iui->config.subflow_sizes[i][j];
+			for (j = 0; j < iui->config.num_subflows; j++)
+				ihdr_rfci->subflow_length[j] = rfci->subflow_sizes[j];
 		}
+		/* early loop termination: */
+		if (last)
+			break;
+	}
+	/* Sanity check: */
+	if (rfci_cnt != iui->config.num_rfci) {
+		LOGP(DLIUUP, LOGL_ERROR, "rfci_cnt %u != num_rfci %u\n",
+			 rfci_cnt, iui->config.num_rfci);
+		msgb_free(msg);
+		return NULL;
 	}
 
 	if (iui->config.IPTIs_present) {
-		uint8_t num_bytes = (num_rfci + 1) / 2;
+		uint8_t num_bytes = (iui->config.num_rfci + 1) / 2;
 		uint8_t *buf = msgb_put(msg, num_bytes);
-		for (i = 0; i < num_bytes - 1; i++)
-			buf[i] = iui->config.IPTIs[i*2] << 4 |
-			      (iui->config.IPTIs[i*2 + 1] & 0x0f);
-		buf[i] = iui->config.IPTIs[i*2] << 4;
-		if (!(num_rfci & 0x01)) /* is even: */
-			buf[i] |= (iui->config.IPTIs[i*2 + 1] & 0x0f);
-
+		rfci_cnt = 0;
+		for (i = 0; i < ARRAY_SIZE(iui->config.rfci); i++) {
+			struct osmo_iuup_rfci *rfci = &iui->config.rfci[i];
+			if (!rfci->used)
+				continue;
+			if (!(rfci_cnt & 0x01)) /* is even: */
+				buf[rfci_cnt / 2] = (((uint8_t)rfci->IPTI) << 4);
+			else
+				buf[rfci_cnt / 2] |= (rfci->IPTI & 0x0F);
+			rfci_cnt++;
+			/* early loop termination: */
+			if (rfci_cnt == iui->config.num_rfci)
+				break;
+		}
 	}
 
 	itail = (struct iuup_ctrl_init_tail *)msgb_put(msg, sizeof(*itail));
@@ -368,12 +391,8 @@ static struct osmo_iuup_rnl_prim *irp_init_ind_alloc(struct osmo_iuup_instance *
 	irp->u.status.u.initialization.data_pdu_type = iui->config.data_pdu_type;
 	irp->u.status.u.initialization.num_subflows = iui->config.num_subflows;
 	irp->u.status.u.initialization.num_rfci = iui->config.num_rfci;
-	memcpy(irp->u.status.u.initialization.subflow_sizes, iui->config.subflow_sizes,
-	       IUUP_MAX_RFCIS * IUUP_MAX_SUBFLOWS * sizeof(iui->config.subflow_sizes[0][0]));
 	irp->u.status.u.initialization.IPTIs_present = iui->config.IPTIs_present;
-	if (iui->config.IPTIs_present)
-		memcpy(irp->u.status.u.initialization.IPTIs, iui->config.IPTIs,
-		       IUUP_MAX_RFCIS * sizeof(iui->config.IPTIs[0]));
+	memcpy(irp->u.status.u.initialization.rfci, iui->config.rfci, sizeof(iui->config.rfci));
 	return irp;
 }
 
@@ -530,24 +549,27 @@ static bool iuup_rx_initialization(struct osmo_iuup_instance *iui, struct osmo_i
 	ihdr_rfci = (struct iuup_ctrl_init_rfci_hdr *)ihdr->rfci_data;
 
 	do {
+		struct osmo_iuup_rfci *rfci = &iui->config.rfci[num_rfci];
 		uint8_t l_size_bytes = ihdr_rfci->li + 1;
 		is_last = ihdr_rfci->lri;
-		if (ihdr_rfci->rfci != num_rfci) {
-			LOGPFSML(iui->fi, LOGL_NOTICE, "Initialization: Unexpected RFCI %u at position %u received\n",
-				 ihdr_rfci->rfci, num_rfci);
+		if (num_rfci >= IUUP_MAX_RFCIS) {
+			LOGPFSML(iui->fi, LOGL_NOTICE, "Initialization: Too many RFCIs received (%u)\n",
+					 num_rfci);
 			err_cause = IUUP_ERR_CAUSE_UNEXPECTED_RFCI;
 			goto send_nack;
 		}
+		rfci->used = 1;
+		rfci->id = ihdr_rfci->rfci;
 		if (l_size_bytes == 2) {
 			uint16_t *subflow_size = (uint16_t *)ihdr_rfci->subflow_length;
 			for (i = 0; i < ihdr->num_subflows_per_rfci; i++) {
-				iui->config.subflow_sizes[ihdr_rfci->rfci][i] = osmo_load16be(subflow_size);
+				rfci->subflow_sizes[i] = osmo_load16be(subflow_size);
 				subflow_size++;
 			}
 		} else {
 			uint8_t *subflow_size = ihdr_rfci->subflow_length;
 			for (i = 0; i < ihdr->num_subflows_per_rfci; i++) {
-				iui->config.subflow_sizes[ihdr_rfci->rfci][i] = *subflow_size;
+				rfci->subflow_sizes[i] = *subflow_size;
 				subflow_size++;
 			}
 		}
@@ -561,19 +583,18 @@ static bool iuup_rx_initialization(struct osmo_iuup_instance *iui, struct osmo_i
 		uint8_t num_bytes = (num_rfci + 1) / 2;
 		iui->config.IPTIs_present = true;
 		for (i = 0; i < num_bytes - 1; i++) {
-			iui->config.IPTIs[i*2] = *buf >> 4;
-			iui->config.IPTIs[i*2 + 1] = *buf & 0x0f;
+			iui->config.rfci[i*2].IPTI = *buf >> 4;
+			iui->config.rfci[i*2 + 1].IPTI = *buf & 0x0f;
 			buf++;
 		}
-		iui->config.IPTIs[i*2] = *buf >> 4;
+		iui->config.rfci[i*2].IPTI = *buf >> 4;
 		if (!(num_rfci & 0x01)) /* is even: */
-			iui->config.IPTIs[i*2 + 1] = *buf & 0x0f;
+			iui->config.rfci[i*2 + 1].IPTI = *buf & 0x0f;
 		buf++;
 		itail = (struct iuup_ctrl_init_tail *)buf;
 	} else {
 		itail = (struct iuup_ctrl_init_tail *)ihdr_rfci;
 	}
-
 	if (itail->data_pdu_type > 1) {
 		LOGPFSML(iui->fi, LOGL_NOTICE, "Initialization: Unexpected Data PDU Type %u received\n", itail->data_pdu_type);
 		err_cause = IUUP_ERR_CAUSE_UNEXPECTED_VALUE;