caif: Bugfix - RFM must support segmentation.

CAIF Remote File Manager may send or receive more than 4050 bytes.
Due to this The CAIF RFM service have to support segmentation.

Signed-off-by: Sjur Braendeland@stericsson.com
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 260 insertions, 54 deletions

diff --git a/net/caif/cfrfml.c b/net/caif/cfrfml.c
index 689cbfd0e43..4b04d25b6a3 100644
--- a/net/caif/cfrfml.c
+++ b/net/caif/cfrfml.c
@@ -7,98 +7,304 @@
 #include <linux/stddef.h>
 #include <linux/spinlock.h>
 #include <linux/slab.h>
+#include <linux/unaligned/le_byteshift.h>
 #include <net/caif/caif_layer.h>
 #include <net/caif/cfsrvl.h>
 #include <net/caif/cfpkt.h>
 
-#define container_obj(layr) container_of(layr, struct cfsrvl, layer)
-
+#define container_obj(layr) container_of(layr, struct cfrfml, serv.layer)
 #define RFM_SEGMENTATION_BIT 0x01
-#define RFM_PAYLOAD  0x00
-#define RFM_CMD_BIT  0x80
-#define RFM_FLOW_OFF 0x81
-#define RFM_FLOW_ON  0x80
-#define RFM_SET_PIN  0x82
-#define RFM_CTRL_PKT_SIZE 1
+#define RFM_HEAD_SIZE 7
 
 static int cfrfml_receive(struct cflayer *layr, struct cfpkt *pkt);
 static int cfrfml_transmit(struct cflayer *layr, struct cfpkt *pkt);
 
-struct cflayer *cfrfml_create(u8 channel_id, struct dev_info *dev_info)
+struct cfrfml {
+	struct cfsrvl serv;
+	struct cfpkt *incomplete_frm;
+	int fragment_size;
+	u8  seghead[6];
+	u16 pdu_size;
+	/* Protects serialized processing of packets */
+	spinlock_t sync;
+};
+
+static void cfrfml_release(struct kref *kref)
+{
+	struct cfsrvl *srvl = container_of(kref, struct cfsrvl, ref);
+	struct cfrfml *rfml = container_obj(&srvl->layer);
+
+	if (rfml->incomplete_frm)
+		cfpkt_destroy(rfml->incomplete_frm);
+
+	kfree(srvl);
+}
+
+struct cflayer *cfrfml_create(u8 channel_id, struct dev_info *dev_info,
+					int mtu_size)
 {
-	struct cfsrvl *rfm = kmalloc(sizeof(struct cfsrvl), GFP_ATOMIC);
+	int tmp;
+	struct cfrfml *this =
+		kzalloc(sizeof(struct cfrfml), GFP_ATOMIC);
 
-	if (!rfm) {
+	if (!this) {
 		pr_warning("CAIF: %s(): Out of memory\n", __func__);
 		return NULL;
 	}
 
-	caif_assert(offsetof(struct cfsrvl, layer) == 0);
+	cfsrvl_init(&this->serv, channel_id, dev_info, false);
+	this->serv.release = cfrfml_release;
+	this->serv.layer.receive = cfrfml_receive;
+	this->serv.layer.transmit = cfrfml_transmit;
+
+	/* Round down to closest multiple of 16 */
+	tmp = (mtu_size - RFM_HEAD_SIZE - 6) / 16;
+	tmp *= 16;
+
+	this->fragment_size = tmp;
+	spin_lock_init(&this->sync);
+	snprintf(this->serv.layer.name, CAIF_LAYER_NAME_SZ,
+		"rfm%d", channel_id);
+
+	return &this->serv.layer;
+}
+
+static struct cfpkt *rfm_append(struct cfrfml *rfml, char *seghead,
+			struct cfpkt *pkt, int *err)
+{
+	struct cfpkt *tmppkt;
+	*err = -EPROTO;
+	/* n-th but not last segment */
+
+	if (cfpkt_extr_head(pkt, seghead, 6) < 0)
+		return NULL;
+
+	/* Verify correct header */
+	if (memcmp(seghead, rfml->seghead, 6) != 0)
+		return NULL;
+
+	tmppkt = cfpkt_append(rfml->incomplete_frm, pkt,
+			rfml->pdu_size + RFM_HEAD_SIZE);
+
+	/* If cfpkt_append failes input pkts are not freed */
+	*err = -ENOMEM;
+	if (tmppkt == NULL)
+		return NULL;
 
-	memset(rfm, 0, sizeof(struct cfsrvl));
-	cfsrvl_init(rfm, channel_id, dev_info, false);
-	rfm->layer.receive = cfrfml_receive;
-	rfm->layer.transmit = cfrfml_transmit;
-	snprintf(rfm->layer.name, CAIF_LAYER_NAME_SZ, "rfm%d", channel_id);
-	return &rfm->layer;
+	*err = 0;
+	return tmppkt;
 }
 
 static int cfrfml_receive(struct cflayer *layr, struct cfpkt *pkt)
 {
 	u8 tmp;
 	bool segmented;
-	int ret;
+	int err;
+	u8 seghead[6];
+	struct cfrfml *rfml;
+	struct cfpkt *tmppkt = NULL;
+
 	caif_assert(layr->up != NULL);
 	caif_assert(layr->receive != NULL);
+	rfml = container_obj(layr);
+	spin_lock(&rfml->sync);
+
+	err = -EPROTO;
+	if (cfpkt_extr_head(pkt, &tmp, 1) < 0)
+		goto out;
+	segmented = tmp & RFM_SEGMENTATION_BIT;
+
+	if (segmented) {
+		if (rfml->incomplete_frm == NULL) {
+			/* Initial Segment */
+			if (cfpkt_peek_head(pkt, rfml->seghead, 6) < 0)
+				goto out;
+
+			rfml->pdu_size = get_unaligned_le16(rfml->seghead+4);
+
+			if (cfpkt_erroneous(pkt))
+				goto out;
+			rfml->incomplete_frm = pkt;
+			pkt = NULL;
+		} else {
+
+			tmppkt = rfm_append(rfml, seghead, pkt, &err);
+			if (tmppkt == NULL)
+				goto out;
+
+			if (cfpkt_erroneous(tmppkt))
+				goto out;
+
+			rfml->incomplete_frm = tmppkt;
+
+
+			if (cfpkt_erroneous(tmppkt))
+				goto out;
+		}
+		err = 0;
+		goto out;
+	}
+
+	if (rfml->incomplete_frm) {
+
+		/* Last Segment */
+		tmppkt = rfm_append(rfml, seghead, pkt, &err);
+		if (tmppkt == NULL)
+			goto out;
+
+		if (cfpkt_erroneous(tmppkt))
+			goto out;
+
+		rfml->incomplete_frm = NULL;
+		pkt = tmppkt;
+		tmppkt = NULL;
+
+		/* Verify that length is correct */
+		err = EPROTO;
+		if (rfml->pdu_size != cfpkt_getlen(pkt) - RFM_HEAD_SIZE + 1)
+			goto out;
+	}
+
+	err = rfml->serv.layer.up->receive(rfml->serv.layer.up, pkt);
+
+out:
+
+	if (err != 0) {
+		if (tmppkt)
+			cfpkt_destroy(tmppkt);
+		if (pkt)
+			cfpkt_destroy(pkt);
+		if (rfml->incomplete_frm)
+			cfpkt_destroy(rfml->incomplete_frm);
+		rfml->incomplete_frm = NULL;
+
+		pr_info("CAIF: %s(): "
+				"Connection error %d triggered on RFM link\n",
+				__func__, err);
+
+		/* Trigger connection error upon failure.*/
+		layr->up->ctrlcmd(layr->up, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND,
+					rfml->serv.dev_info.id);
+	}
+	spin_unlock(&rfml->sync);
+	return err;
+}
+
+
+static int cfrfml_transmit_segment(struct cfrfml *rfml, struct cfpkt *pkt)
+{
+	caif_assert(!cfpkt_getlen(pkt) < rfml->fragment_size);
+
+	/* Add info for MUX-layer to route the packet out. */
+	cfpkt_info(pkt)->channel_id = rfml->serv.layer.id;
 
 	/*
-	 * RFM is taking care of segmentation and stripping of
-	 * segmentation bit.
+	 * To optimize alignment, we add up the size of CAIF header before
+	 * payload.
 	 */
-	if (cfpkt_extr_head(pkt, &tmp, 1) < 0) {
-		pr_err("CAIF: %s(): Packet is erroneous!\n", __func__);
-		cfpkt_destroy(pkt);
-		return -EPROTO;
-	}
-	segmented = tmp & RFM_SEGMENTATION_BIT;
-	caif_assert(!segmented);
+	cfpkt_info(pkt)->hdr_len = RFM_HEAD_SIZE;
+	cfpkt_info(pkt)->dev_info = &rfml->serv.dev_info;
 
-	ret = layr->up->receive(layr->up, pkt);
-	return ret;
+	return rfml->serv.layer.dn->transmit(rfml->serv.layer.dn, pkt);
 }
 
 static int cfrfml_transmit(struct cflayer *layr, struct cfpkt *pkt)
 {
-	u8 tmp = 0;
-	int ret;
-	struct cfsrvl *service = container_obj(layr);
+	int err;
+	u8 seg;
+	u8 head[6];
+	struct cfpkt *rearpkt = NULL;
+	struct cfpkt *frontpkt = pkt;
+	struct cfrfml *rfml = container_obj(layr);
 
 	caif_assert(layr->dn != NULL);
 	caif_assert(layr->dn->transmit != NULL);
 
-	if (!cfsrvl_ready(service, &ret))
-		return ret;
+	if (!cfsrvl_ready(&rfml->serv, &err))
+		return err;
+
+	err = -EPROTO;
+	if (cfpkt_getlen(pkt) <= RFM_HEAD_SIZE-1)
+		goto out;
+
+	err = 0;
+	if (cfpkt_getlen(pkt) > rfml->fragment_size + RFM_HEAD_SIZE)
+		err = cfpkt_peek_head(pkt, head, 6);
+
+	if (err < 0)
+		goto out;
+
+	while (cfpkt_getlen(frontpkt) > rfml->fragment_size + RFM_HEAD_SIZE) {
+
+		seg = 1;
+		err = -EPROTO;
+
+		if (cfpkt_add_head(frontpkt, &seg, 1) < 0)
+			goto out;
+		/*
+		 * On OOM error cfpkt_split returns NULL.
+		 *
+		 * NOTE: Segmented pdu is not correctly aligned.
+		 * This has negative performance impact.
+		 */
+
+		rearpkt = cfpkt_split(frontpkt, rfml->fragment_size);
+		if (rearpkt == NULL)
+			goto out;
+
+		err = cfrfml_transmit_segment(rfml, frontpkt);
+
+		if (err != 0)
+			goto out;
+		frontpkt = rearpkt;
+		rearpkt = NULL;
+
+		err = -ENOMEM;
+		if (frontpkt == NULL)
+			goto out;
+		err = -EPROTO;
+		if (cfpkt_add_head(frontpkt, head, 6) < 0)
+			goto out;
 
-	if (cfpkt_getlen(pkt) > CAIF_MAX_PAYLOAD_SIZE) {
-		pr_err("CAIF: %s():Packet too large - size=%d\n",
-			__func__, cfpkt_getlen(pkt));
-		return -EOVERFLOW;
 	}
-	if (cfpkt_add_head(pkt, &tmp, 1) < 0) {
-		pr_err("CAIF: %s(): Packet is erroneous!\n", __func__);
-		return -EPROTO;
+
+	seg = 0;
+	err = -EPROTO;
+
+	if (cfpkt_add_head(frontpkt, &seg, 1) < 0)
+		goto out;
+
+	err = cfrfml_transmit_segment(rfml, frontpkt);
+
+	frontpkt = NULL;
+out:
+
+	if (err != 0) {
+		pr_info("CAIF: %s(): "
+				"Connection error %d triggered on RFM link\n",
+				__func__, err);
+		/* Trigger connection error upon failure.*/
+
+		layr->up->ctrlcmd(layr->up, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND,
+					rfml->serv.dev_info.id);
+
+		if (rearpkt)
+			cfpkt_destroy(rearpkt);
+
+		if (frontpkt && frontpkt != pkt) {
+
+			cfpkt_destroy(frontpkt);
+			/*
+			 * Socket layer will free the original packet,
+			 * but this packet may already be sent and
+			 * freed. So we have to return 0 in this case
+			 * to avoid socket layer to re-free this packet.
+			 * The return of shutdown indication will
+			 * cause connection to be invalidated anyhow.
+			 */
+			err = 0;
+		}
 	}
 
-	/* Add info for MUX-layer to route the packet out. */
-	cfpkt_info(pkt)->channel_id = service->layer.id;
-	/*
-	 * To optimize alignment, we add up the size of CAIF header before
-	 * payload.
-	 */
-	cfpkt_info(pkt)->hdr_len = 1;
-	cfpkt_info(pkt)->dev_info = &service->dev_info;
-	ret = layr->dn->transmit(layr->dn, pkt);
-	if (ret < 0)
-		cfpkt_extr_head(pkt, &tmp, 1);
-	return ret;
+	return err;
 }