net/caif/cfrfml.c

   1 /*
   2  * Copyright (C) ST-Ericsson AB 2010
   3  * Author:      Sjur Brendeland/sjur.brandeland@stericsson.com
   4  * License terms: GNU General Public License (GPL) version 2
   5  */
   6
   7 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
   8
   9 #include <linux/stddef.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/slab.h>
  12 #include <asm/unaligned.h>
  13 #include <net/caif/caif_layer.h>
  14 #include <net/caif/cfsrvl.h>
  15 #include <net/caif/cfpkt.h>
  16
  17 #define container_obj(layr) container_of(layr, struct cfrfml, serv.layer)
  18 #define RFM_SEGMENTATION_BIT 0x01
  19 #define RFM_HEAD_SIZE 7
  20
  21 static int cfrfml_receive(struct cflayer *layr, struct cfpkt *pkt);
  22 static int cfrfml_transmit(struct cflayer *layr, struct cfpkt *pkt);
  23
  24 struct cfrfml {
  25         struct cfsrvl serv;
  26         struct cfpkt *incomplete_frm;
  27         int fragment_size;
  28         u8  seghead[6];
  29         u16 pdu_size;
  30         /* Protects serialized processing of packets */
  31         spinlock_t sync;
  32 };
  33
  34 static void cfrfml_release(struct kref *kref)
  35 {
  36         struct cfsrvl *srvl = container_of(kref, struct cfsrvl, ref);
  37         struct cfrfml *rfml = container_obj(&srvl->layer);
  38
  39         if (rfml->incomplete_frm)
  40                 cfpkt_destroy(rfml->incomplete_frm);
  41
  42         kfree(srvl);
  43 }
  44
  45 struct cflayer *cfrfml_create(u8 channel_id, struct dev_info *dev_info,
  46                                         int mtu_size)
  47 {
  48         int tmp;
  49         struct cfrfml *this =
  50                 kzalloc(sizeof(struct cfrfml), GFP_ATOMIC);
  51
  52         if (!this) {
  53                 pr_warn("Out of memory\n");
  54                 return NULL;
  55         }
  56
  57         cfsrvl_init(&this->serv, channel_id, dev_info, false);
  58         this->serv.release = cfrfml_release;
  59         this->serv.layer.receive = cfrfml_receive;
  60         this->serv.layer.transmit = cfrfml_transmit;
  61
  62         /* Round down to closest multiple of 16 */
  63         tmp = (mtu_size - RFM_HEAD_SIZE - 6) / 16;
  64         tmp *= 16;
  65
  66         this->fragment_size = tmp;
  67         spin_lock_init(&this->sync);
  68         snprintf(this->serv.layer.name, CAIF_LAYER_NAME_SZ,
  69                 "rfm%d", channel_id);
  70
  71         return &this->serv.layer;
  72 }
  73
  74 static struct cfpkt *rfm_append(struct cfrfml *rfml, char *seghead,
  75                         struct cfpkt *pkt, int *err)
  76 {
  77         struct cfpkt *tmppkt;
  78         *err = -EPROTO;
  79         /* n-th but not last segment */
  80
  81         if (cfpkt_extr_head(pkt, seghead, 6) < 0)
  82                 return NULL;
  83
  84         /* Verify correct header */
  85         if (memcmp(seghead, rfml->seghead, 6) != 0)
  86                 return NULL;
  87
  88         tmppkt = cfpkt_append(rfml->incomplete_frm, pkt,
  89                         rfml->pdu_size + RFM_HEAD_SIZE);
  90
  91         /* If cfpkt_append failes input pkts are not freed */
  92         *err = -ENOMEM;
  93         if (tmppkt == NULL)
  94                 return NULL;
  95
  96         *err = 0;
  97         return tmppkt;
  98 }
  99
 100 static int cfrfml_receive(struct cflayer *layr, struct cfpkt *pkt)
 101 {
 102         u8 tmp;
 103         bool segmented;
 104         int err;
 105         u8 seghead[6];
 106         struct cfrfml *rfml;
 107         struct cfpkt *tmppkt = NULL;
 108
 109         caif_assert(layr->up != NULL);
 110         caif_assert(layr->receive != NULL);
 111         rfml = container_obj(layr);
 112         spin_lock(&rfml->sync);
 113
 114         err = -EPROTO;
 115         if (cfpkt_extr_head(pkt, &tmp, 1) < 0)
 116                 goto out;
 117         segmented = tmp & RFM_SEGMENTATION_BIT;
 118
 119         if (segmented) {
 120                 if (rfml->incomplete_frm == NULL) {
 121                         /* Initial Segment */
 122                         if (cfpkt_peek_head(pkt, rfml->seghead, 6) < 0)
 123                                 goto out;
 124
 125                         rfml->pdu_size = get_unaligned_le16(rfml->seghead+4);
 126
 127                         if (cfpkt_erroneous(pkt))
 128                                 goto out;
 129                         rfml->incomplete_frm = pkt;
 130                         pkt = NULL;
 131                 } else {
 132
 133                         tmppkt = rfm_append(rfml, seghead, pkt, &err);
 134                         if (tmppkt == NULL)
 135                                 goto out;
 136
 137                         if (cfpkt_erroneous(tmppkt))
 138                                 goto out;
 139
 140                         rfml->incomplete_frm = tmppkt;
 141
 142
 143                         if (cfpkt_erroneous(tmppkt))
 144                                 goto out;
 145                 }
 146                 err = 0;
 147                 goto out;
 148         }
 149
 150         if (rfml->incomplete_frm) {
 151
 152                 /* Last Segment */
 153                 tmppkt = rfm_append(rfml, seghead, pkt, &err);
 154                 if (tmppkt == NULL)
 155                         goto out;
 156
 157                 if (cfpkt_erroneous(tmppkt))
 158                         goto out;
 159
 160                 rfml->incomplete_frm = NULL;
 161                 pkt = tmppkt;
 162                 tmppkt = NULL;
 163
 164                 /* Verify that length is correct */
 165                 err = EPROTO;
 166                 if (rfml->pdu_size != cfpkt_getlen(pkt) - RFM_HEAD_SIZE + 1)
 167                         goto out;
 168         }
 169
 170         err = rfml->serv.layer.up->receive(rfml->serv.layer.up, pkt);
 171
 172 out:
 173
 174         if (err != 0) {
 175                 if (tmppkt)
 176                         cfpkt_destroy(tmppkt);
 177                 if (pkt)
 178                         cfpkt_destroy(pkt);
 179                 if (rfml->incomplete_frm)
 180                         cfpkt_destroy(rfml->incomplete_frm);
 181                 rfml->incomplete_frm = NULL;
 182
 183                 pr_info("Connection error %d triggered on RFM link\n", err);
 184
 185                 /* Trigger connection error upon failure.*/
 186                 layr->up->ctrlcmd(layr->up, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND,
 187                                         rfml->serv.dev_info.id);
 188         }
 189         spin_unlock(&rfml->sync);
 190         return err;
 191 }
 192
 193
 194 static int cfrfml_transmit_segment(struct cfrfml *rfml, struct cfpkt *pkt)
 195 {
 196         caif_assert(cfpkt_getlen(pkt) >= rfml->fragment_size);
 197
 198         /* Add info for MUX-layer to route the packet out. */
 199         cfpkt_info(pkt)->channel_id = rfml->serv.layer.id;
 200
 201         /*
 202          * To optimize alignment, we add up the size of CAIF header before
 203          * payload.
 204          */
 205         cfpkt_info(pkt)->hdr_len = RFM_HEAD_SIZE;
 206         cfpkt_info(pkt)->dev_info = &rfml->serv.dev_info;
 207
 208         return rfml->serv.layer.dn->transmit(rfml->serv.layer.dn, pkt);
 209 }
 210
 211 static int cfrfml_transmit(struct cflayer *layr, struct cfpkt *pkt)
 212 {
 213         int err;
 214         u8 seg;
 215         u8 head[6];
 216         struct cfpkt *rearpkt = NULL;
 217         struct cfpkt *frontpkt = pkt;
 218         struct cfrfml *rfml = container_obj(layr);
 219
 220         caif_assert(layr->dn != NULL);
 221         caif_assert(layr->dn->transmit != NULL);
 222
 223         if (!cfsrvl_ready(&rfml->serv, &err))
 224                 return err;
 225
 226         err = -EPROTO;
 227         if (cfpkt_getlen(pkt) <= RFM_HEAD_SIZE-1)
 228                 goto out;
 229
 230         err = 0;
 231         if (cfpkt_getlen(pkt) > rfml->fragment_size + RFM_HEAD_SIZE)
 232                 err = cfpkt_peek_head(pkt, head, 6);
 233
 234         if (err < 0)
 235                 goto out;
 236
 237         while (cfpkt_getlen(frontpkt) > rfml->fragment_size + RFM_HEAD_SIZE) {
 238
 239                 seg = 1;
 240                 err = -EPROTO;
 241
 242                 if (cfpkt_add_head(frontpkt, &seg, 1) < 0)
 243                         goto out;
 244                 /*
 245                  * On OOM error cfpkt_split returns NULL.
 246                  *
 247                  * NOTE: Segmented pdu is not correctly aligned.
 248                  * This has negative performance impact.
 249                  */
 250
 251                 rearpkt = cfpkt_split(frontpkt, rfml->fragment_size);
 252                 if (rearpkt == NULL)
 253                         goto out;
 254
 255                 err = cfrfml_transmit_segment(rfml, frontpkt);
 256
 257                 if (err != 0)
 258                         goto out;
 259                 frontpkt = rearpkt;
 260                 rearpkt = NULL;
 261
 262                 err = -ENOMEM;
 263                 if (frontpkt == NULL)
 264                         goto out;
 265                 err = -EPROTO;
 266                 if (cfpkt_add_head(frontpkt, head, 6) < 0)
 267                         goto out;
 268
 269         }
 270
 271         seg = 0;
 272         err = -EPROTO;
 273
 274         if (cfpkt_add_head(frontpkt, &seg, 1) < 0)
 275                 goto out;
 276
 277         err = cfrfml_transmit_segment(rfml, frontpkt);
 278
 279         frontpkt = NULL;
 280 out:
 281
 282         if (err != 0) {
 283                 pr_info("Connection error %d triggered on RFM link\n", err);
 284                 /* Trigger connection error upon failure.*/
 285
 286                 layr->up->ctrlcmd(layr->up, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND,
 287                                         rfml->serv.dev_info.id);
 288
 289                 if (rearpkt)
 290                         cfpkt_destroy(rearpkt);
 291
 292                 if (frontpkt && frontpkt != pkt) {
 293
 294                         cfpkt_destroy(frontpkt);
 295                         /*
 296                          * Socket layer will free the original packet,
 297                          * but this packet may already be sent and
 298                          * freed. So we have to return 0 in this case
 299                          * to avoid socket layer to re-free this packet.
 300                          * The return of shutdown indication will
 301                          * cause connection to be invalidated anyhow.
 302                          */
 303                         err = 0;
 304                 }
 305         }
 306
 307         return err;
 308 }