kernel/net/caif/cfrfml.c

   1 /*
   2  * Copyright (C) ST-Ericsson AB 2010
   3  * Author:      Sjur Brendeland
   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 cflayer *layer)
  35 {
  36         struct cfsrvl *srvl = container_of(layer, struct cfsrvl, layer);
  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 = kzalloc(sizeof(struct cfrfml), GFP_ATOMIC);
  50
  51         if (!this)
  52                 return NULL;
  53
  54         cfsrvl_init(&this->serv, channel_id, dev_info, false);
  55         this->serv.release = cfrfml_release;
  56         this->serv.layer.receive = cfrfml_receive;
  57         this->serv.layer.transmit = cfrfml_transmit;
  58
  59         /* Round down to closest multiple of 16 */
  60         tmp = (mtu_size - RFM_HEAD_SIZE - 6) / 16;
  61         tmp *= 16;
  62
  63         this->fragment_size = tmp;
  64         spin_lock_init(&this->sync);
  65         snprintf(this->serv.layer.name, CAIF_LAYER_NAME_SZ,
  66                 "rfm%d", channel_id);
  67
  68         return &this->serv.layer;
  69 }
  70
  71 static struct cfpkt *rfm_append(struct cfrfml *rfml, char *seghead,
  72                                 struct cfpkt *pkt, int *err)
  73 {
  74         struct cfpkt *tmppkt;
  75         *err = -EPROTO;
  76         /* n-th but not last segment */
  77
  78         if (cfpkt_extr_head(pkt, seghead, 6) < 0)
  79                 return NULL;
  80
  81         /* Verify correct header */
  82         if (memcmp(seghead, rfml->seghead, 6) != 0)
  83                 return NULL;
  84
  85         tmppkt = cfpkt_append(rfml->incomplete_frm, pkt,
  86                         rfml->pdu_size + RFM_HEAD_SIZE);
  87
  88         /* If cfpkt_append failes input pkts are not freed */
  89         *err = -ENOMEM;
  90         if (tmppkt == NULL)
  91                 return NULL;
  92
  93         *err = 0;
  94         return tmppkt;
  95 }
  96
  97 static int cfrfml_receive(struct cflayer *layr, struct cfpkt *pkt)
  98 {
  99         u8 tmp;
 100         bool segmented;
 101         int err;
 102         u8 seghead[6];
 103         struct cfrfml *rfml;
 104         struct cfpkt *tmppkt = NULL;
 105
 106         caif_assert(layr->up != NULL);
 107         caif_assert(layr->receive != NULL);
 108         rfml = container_obj(layr);
 109         spin_lock(&rfml->sync);
 110
 111         err = -EPROTO;
 112         if (cfpkt_extr_head(pkt, &tmp, 1) < 0)
 113                 goto out;
 114         segmented = tmp & RFM_SEGMENTATION_BIT;
 115
 116         if (segmented) {
 117                 if (rfml->incomplete_frm == NULL) {
 118                         /* Initial Segment */
 119                         if (cfpkt_peek_head(pkt, rfml->seghead, 6) < 0)
 120                                 goto out;
 121
 122                         rfml->pdu_size = get_unaligned_le16(rfml->seghead+4);
 123
 124                         if (cfpkt_erroneous(pkt))
 125                                 goto out;
 126                         rfml->incomplete_frm = pkt;
 127                         pkt = NULL;
 128                 } else {
 129
 130                         tmppkt = rfm_append(rfml, seghead, pkt, &err);
 131                         if (tmppkt == NULL)
 132                                 goto out;
 133
 134                         if (cfpkt_erroneous(tmppkt))
 135                                 goto out;
 136
 137                         rfml->incomplete_frm = tmppkt;
 138
 139
 140                         if (cfpkt_erroneous(tmppkt))
 141                                 goto out;
 142                 }
 143                 err = 0;
 144                 goto out;
 145         }
 146
 147         if (rfml->incomplete_frm) {
 148
 149                 /* Last Segment */
 150                 tmppkt = rfm_append(rfml, seghead, pkt, &err);
 151                 if (tmppkt == NULL)
 152                         goto out;
 153
 154                 if (cfpkt_erroneous(tmppkt))
 155                         goto out;
 156
 157                 rfml->incomplete_frm = NULL;
 158                 pkt = tmppkt;
 159                 tmppkt = NULL;
 160
 161                 /* Verify that length is correct */
 162                 err = EPROTO;
 163                 if (rfml->pdu_size != cfpkt_getlen(pkt) - RFM_HEAD_SIZE + 1)
 164                         goto out;
 165         }
 166
 167         err = rfml->serv.layer.up->receive(rfml->serv.layer.up, pkt);
 168
 169 out:
 170
 171         if (err != 0) {
 172                 if (tmppkt)
 173                         cfpkt_destroy(tmppkt);
 174                 if (pkt)
 175                         cfpkt_destroy(pkt);
 176                 if (rfml->incomplete_frm)
 177                         cfpkt_destroy(rfml->incomplete_frm);
 178                 rfml->incomplete_frm = NULL;
 179
 180                 pr_info("Connection error %d triggered on RFM link\n", err);
 181
 182                 /* Trigger connection error upon failure.*/
 183                 layr->up->ctrlcmd(layr->up, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND,
 184                                         rfml->serv.dev_info.id);
 185         }
 186         spin_unlock(&rfml->sync);
 187
 188         if (unlikely(err == -EAGAIN))
 189                 /* It is not possible to recover after drop of a fragment */
 190                 err = -EIO;
 191
 192         return err;
 193 }
 194
 195
 196 static int cfrfml_transmit_segment(struct cfrfml *rfml, struct cfpkt *pkt)
 197 {
 198         caif_assert(cfpkt_getlen(pkt) < rfml->fragment_size + RFM_HEAD_SIZE);
 199
 200         /* Add info for MUX-layer to route the packet out. */
 201         cfpkt_info(pkt)->channel_id = rfml->serv.layer.id;
 202
 203         /*
 204          * To optimize alignment, we add up the size of CAIF header before
 205          * payload.
 206          */
 207         cfpkt_info(pkt)->hdr_len = RFM_HEAD_SIZE;
 208         cfpkt_info(pkt)->dev_info = &rfml->serv.dev_info;
 209
 210         return rfml->serv.layer.dn->transmit(rfml->serv.layer.dn, pkt);
 211 }
 212
 213 static int cfrfml_transmit(struct cflayer *layr, struct cfpkt *pkt)
 214 {
 215         int err;
 216         u8 seg;
 217         u8 head[6];
 218         struct cfpkt *rearpkt = NULL;
 219         struct cfpkt *frontpkt = pkt;
 220         struct cfrfml *rfml = container_obj(layr);
 221
 222         caif_assert(layr->dn != NULL);
 223         caif_assert(layr->dn->transmit != NULL);
 224
 225         if (!cfsrvl_ready(&rfml->serv, &err))
 226                 goto out;
 227
 228         err = -EPROTO;
 229         if (cfpkt_getlen(pkt) <= RFM_HEAD_SIZE-1)
 230                 goto out;
 231
 232         err = 0;
 233         if (cfpkt_getlen(pkt) > rfml->fragment_size + RFM_HEAD_SIZE)
 234                 err = cfpkt_peek_head(pkt, head, 6);
 235
 236         if (err < 0)
 237                 goto out;
 238
 239         while (cfpkt_getlen(frontpkt) > rfml->fragment_size + RFM_HEAD_SIZE) {
 240
 241                 seg = 1;
 242                 err = -EPROTO;
 243
 244                 if (cfpkt_add_head(frontpkt, &seg, 1) < 0)
 245                         goto out;
 246                 /*
 247                  * On OOM error cfpkt_split returns NULL.
 248                  *
 249                  * NOTE: Segmented pdu is not correctly aligned.
 250                  * This has negative performance impact.
 251                  */
 252
 253                 rearpkt = cfpkt_split(frontpkt, rfml->fragment_size);
 254                 if (rearpkt == NULL)
 255                         goto out;
 256
 257                 err = cfrfml_transmit_segment(rfml, frontpkt);
 258
 259                 if (err != 0) {
 260                         frontpkt = NULL;
 261                         goto out;
 262                 }
 263
 264                 frontpkt = rearpkt;
 265                 rearpkt = NULL;
 266
 267                 err = -ENOMEM;
 268                 if (frontpkt == NULL)
 269                         goto out;
 270                 err = -EPROTO;
 271                 if (cfpkt_add_head(frontpkt, head, 6) < 0)
 272                         goto out;
 273
 274         }
 275
 276         seg = 0;
 277         err = -EPROTO;
 278
 279         if (cfpkt_add_head(frontpkt, &seg, 1) < 0)
 280                 goto out;
 281
 282         err = cfrfml_transmit_segment(rfml, frontpkt);
 283
 284         frontpkt = NULL;
 285 out:
 286
 287         if (err != 0) {
 288                 pr_info("Connection error %d triggered on RFM link\n", err);
 289                 /* Trigger connection error upon failure.*/
 290
 291                 layr->up->ctrlcmd(layr->up, CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND,
 292                                         rfml->serv.dev_info.id);
 293
 294                 if (rearpkt)
 295                         cfpkt_destroy(rearpkt);
 296
 297                 if (frontpkt)
 298                         cfpkt_destroy(frontpkt);
 299         }
 300
 301         return err;
 302 }