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>

5 files changed, 271 insertions, 65 deletions

diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
index 791249316ef3..848ae755cdd6 100644
--- a/net/caif/caif_socket.c
+++ b/net/caif/caif_socket.c
@@ -596,10 +596,6 @@ static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
 
         buffer_size = len + CAIF_NEEDED_HEADROOM + CAIF_NEEDED_TAILROOM;
 
-        ret = -EMSGSIZE;
-        if (buffer_size > CAIF_MAX_PAYLOAD_SIZE)
-                goto err;
-
         timeo = sock_sndtimeo(sk, noblock);
         timeo = caif_wait_for_flow_on(container_of(sk, struct caifsock, sk),
                                 1, timeo, &ret);
diff --git a/net/caif/cfcnfg.c b/net/caif/cfcnfg.c
index 7c81974a45c4..cff2dcb9efe4 100644
--- a/net/caif/cfcnfg.c
+++ b/net/caif/cfcnfg.c
@@ -22,6 +22,7 @@
 #define PHY_NAME_LEN 20
 
 #define container_obj(layr) container_of(layr, struct cfcnfg, layer)
+#define RFM_FRAGMENT_SIZE 4030
 
 /* Information about CAIF physical interfaces held by Config Module in order
  * to manage physical interfaces
@@ -328,7 +329,8 @@ cfcnfg_linkup_rsp(struct cflayer *layer, u8 channel_id, enum cfctrl_srv serv,
                 servicel = cfdgml_create(channel_id, &phyinfo->dev_info);
                 break;
         case CFCTRL_SRV_RFM:
-                servicel = cfrfml_create(channel_id, &phyinfo->dev_info);
+                servicel = cfrfml_create(channel_id, &phyinfo->dev_info,
+                                                RFM_FRAGMENT_SIZE);
                 break;
         case CFCTRL_SRV_UTIL:
                 servicel = cfutill_create(channel_id, &phyinfo->dev_info);
diff --git a/net/caif/cfpkt_skbuff.c b/net/caif/cfpkt_skbuff.c
index a6fdf899741a..318b0f4b416e 100644
--- a/net/caif/cfpkt_skbuff.c
+++ b/net/caif/cfpkt_skbuff.c
@@ -338,7 +338,6 @@ struct cfpkt *cfpkt_append(struct cfpkt *dstpkt,
         u16 dstlen;
         u16 createlen;
         if (unlikely(is_erronous(dstpkt) || is_erronous(addpkt))) {
-                cfpkt_destroy(addpkt);
                 return dstpkt;
         }
         if (expectlen > addlen)
diff --git a/net/caif/cfrfml.c b/net/caif/cfrfml.c
index 689cbfd0e43d..4b04d25b6a3f 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;
 }
diff --git a/net/caif/cfsrvl.c b/net/caif/cfsrvl.c
index 7aa1f03a0151..4c9f147c38af 100644
--- a/net/caif/cfsrvl.c
+++ b/net/caif/cfsrvl.c
@@ -159,6 +159,13 @@ void cfservl_destroy(struct cflayer *layer)
         kfree(layer);
 }
 
+void cfsrvl_release(struct kref *kref)
+{
+        struct cfsrvl *service = container_of(kref, struct cfsrvl, ref);
+        pr_info("CAIF: %s(): enter\n", __func__);
+        kfree(service);
+}
+
 void cfsrvl_init(struct cfsrvl *service,
                         u8 channel_id,
                         struct dev_info *dev_info,
@@ -174,14 +181,10 @@ void cfsrvl_init(struct cfsrvl *service,
         service->layer.modemcmd = cfservl_modemcmd;
         service->dev_info = *dev_info;
         service->supports_flowctrl = supports_flowctrl;
+        service->release = cfsrvl_release;
         kref_init(&service->ref);
 }
 
-void cfsrvl_release(struct kref *kref)
-{
-        struct cfsrvl *service = container_of(kref, struct cfsrvl, ref);
-        kfree(service);
-}
 
 bool cfsrvl_ready(struct cfsrvl *service, int *err)
 {