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/*
* Copyright (C) ST-Ericsson AB 2010
* Author: Sjur Brendeland/sjur.brandeland@stericsson.com
* License terms: GNU General Public License (GPL) version 2
*/
#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
#include <linux/stddef.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <asm/unaligned.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 cfrfml, serv.layer)
#define RFM_SEGMENTATION_BIT 0x01
#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 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 cflayer *layer)
{
struct cfsrvl *srvl = container_of(layer, struct cfsrvl, layer);
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)
{
int tmp;
struct cfrfml *this = kzalloc(sizeof(struct cfrfml), GFP_ATOMIC);
if (!this)
return NULL;
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;
*err = 0;
return tmppkt;
}
static int cfrfml_receive(struct cflayer *layr, struct cfpkt *pkt)
{
u8 tmp;
bool segmented;
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("Connection error %d triggered on RFM link\n", 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);
if (unlikely(err == -EAGAIN))
/* It is not possible to recover after drop of a fragment */
err = -EIO;
return err;
}
static int cfrfml_transmit_segment(struct cfrfml *rfml, struct cfpkt *pkt)
{
caif_assert(cfpkt_getlen(pkt) < rfml->fragment_size + RFM_HEAD_SIZE);
/* Add info for MUX-layer to route the packet out. */
cfpkt_info(pkt)->channel_id = rfml->serv.layer.id;
/*
* To optimize alignment, we add up the size of CAIF header before
* payload.
*/
cfpkt_info(pkt)->hdr_len = RFM_HEAD_SIZE;
cfpkt_info(pkt)->dev_info = &rfml->serv.dev_info;
return rfml->serv.layer.dn->transmit(rfml->serv.layer.dn, pkt);
}
static int cfrfml_transmit(struct cflayer *layr, struct cfpkt *pkt)
{
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(&rfml->serv, &err))
goto out;
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) {
frontpkt = NULL;
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;
}
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("Connection error %d triggered on RFM link\n", 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)
cfpkt_destroy(frontpkt);
}
return err;
}
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