net/phonet/datagram.c

   1 /*
   2  * File: datagram.c
   3  *
   4  * Datagram (ISI) Phonet sockets
   5  *
   6  * Copyright (C) 2008 Nokia Corporation.
   7  *
   8  * Contact: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
   9  * Original author: Sakari Ailus <sakari.ailus@nokia.com>
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * version 2 as published by the Free Software Foundation.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  23  * 02110-1301 USA
  24  */
  25
  26 #include <linux/kernel.h>
  27 #include <linux/socket.h>
  28 #include <asm/ioctls.h>
  29 #include <net/sock.h>
  30
  31 #include <linux/phonet.h>
  32 #include <net/phonet/phonet.h>
  33
  34 static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb);
  35
  36 /* associated socket ceases to exist */
  37 static void pn_sock_close(struct sock *sk, long timeout)
  38 {
  39         sk_common_release(sk);
  40 }
  41
  42 static int pn_ioctl(struct sock *sk, int cmd, unsigned long arg)
  43 {
  44         struct sk_buff *skb;
  45         int answ;
  46
  47         switch (cmd) {
  48         case SIOCINQ:
  49                 lock_sock(sk);
  50                 skb = skb_peek(&sk->sk_receive_queue);
  51                 answ = skb ? skb->len : 0;
  52                 release_sock(sk);
  53                 return put_user(answ, (int __user *)arg);
  54         }
  55
  56         return -ENOIOCTLCMD;
  57 }
  58
  59 /* Destroy socket. All references are gone. */
  60 static void pn_destruct(struct sock *sk)
  61 {
  62         skb_queue_purge(&sk->sk_receive_queue);
  63 }
  64
  65 static int pn_init(struct sock *sk)
  66 {
  67         sk->sk_destruct = pn_destruct;
  68         return 0;
  69 }
  70
  71 static int pn_sendmsg(struct kiocb *iocb, struct sock *sk,
  72                         struct msghdr *msg, size_t len)
  73 {
  74         struct sockaddr_pn *target;
  75         struct sk_buff *skb;
  76         int err;
  77
  78         if (msg->msg_flags & MSG_OOB)
  79                 return -EOPNOTSUPP;
  80
  81         if (msg->msg_name == NULL)
  82                 return -EDESTADDRREQ;
  83
  84         if (msg->msg_namelen < sizeof(struct sockaddr_pn))
  85                 return -EINVAL;
  86
  87         target = (struct sockaddr_pn *)msg->msg_name;
  88         if (target->spn_family != AF_PHONET)
  89                 return -EAFNOSUPPORT;
  90
  91         skb = sock_alloc_send_skb(sk, MAX_PHONET_HEADER + len,
  92                                         msg->msg_flags & MSG_DONTWAIT, &err);
  93         if (skb == NULL)
  94                 return err;
  95         skb_reserve(skb, MAX_PHONET_HEADER);
  96
  97         err = memcpy_fromiovec((void *)skb_put(skb, len), msg->msg_iov, len);
  98         if (err < 0) {
  99                 kfree_skb(skb);
 100                 return err;
 101         }
 102
 103         /*
 104          * Fill in the Phonet header and
 105          * finally pass the packet forwards.
 106          */
 107         err = pn_skb_send(sk, skb, target);
 108
 109         /* If ok, return len. */
 110         return (err >= 0) ? len : err;
 111 }
 112
 113 static int pn_recvmsg(struct kiocb *iocb, struct sock *sk,
 114                         struct msghdr *msg, size_t len, int noblock,
 115                         int flags, int *addr_len)
 116 {
 117         struct sk_buff *skb = NULL;
 118         struct sockaddr_pn sa;
 119         int rval = -EOPNOTSUPP;
 120         int copylen;
 121
 122         if (flags & MSG_OOB)
 123                 goto out_nofree;
 124
 125         if (addr_len)
 126                 *addr_len = sizeof(sa);
 127
 128         skb = skb_recv_datagram(sk, flags, noblock, &rval);
 129         if (skb == NULL)
 130                 goto out_nofree;
 131
 132         pn_skb_get_src_sockaddr(skb, &sa);
 133
 134         copylen = skb->len;
 135         if (len < copylen) {
 136                 msg->msg_flags |= MSG_TRUNC;
 137                 copylen = len;
 138         }
 139
 140         rval = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copylen);
 141         if (rval) {
 142                 rval = -EFAULT;
 143                 goto out;
 144         }
 145
 146         rval = (flags & MSG_TRUNC) ? skb->len : copylen;
 147
 148         if (msg->msg_name != NULL)
 149                 memcpy(msg->msg_name, &sa, sizeof(struct sockaddr_pn));
 150
 151 out:
 152         skb_free_datagram(sk, skb);
 153
 154 out_nofree:
 155         return rval;
 156 }
 157
 158 /* Queue an skb for a sock. */
 159 static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb)
 160 {
 161         int err = sock_queue_rcv_skb(sk, skb);
 162         if (err < 0) {
 163                 kfree_skb(skb);
 164                 if (err == -ENOMEM)
 165                         atomic_inc(&sk->sk_drops);
 166         }
 167         return err ? NET_RX_DROP : NET_RX_SUCCESS;
 168 }
 169
 170 /* Module registration */
 171 static struct proto pn_proto = {
 172         .close          = pn_sock_close,
 173         .ioctl          = pn_ioctl,
 174         .init           = pn_init,
 175         .sendmsg        = pn_sendmsg,
 176         .recvmsg        = pn_recvmsg,
 177         .backlog_rcv    = pn_backlog_rcv,
 178         .hash           = pn_sock_hash,
 179         .unhash         = pn_sock_unhash,
 180         .get_port       = pn_sock_get_port,
 181         .obj_size       = sizeof(struct pn_sock),
 182         .owner          = THIS_MODULE,
 183         .name           = "PHONET",
 184 };
 185
 186 static struct phonet_protocol pn_dgram_proto = {
 187         .ops            = &phonet_dgram_ops,
 188         .prot           = &pn_proto,
 189         .sock_type      = SOCK_DGRAM,
 190 };
 191
 192 int __init isi_register(void)
 193 {
 194         return phonet_proto_register(PN_PROTO_PHONET, &pn_dgram_proto);
 195 }
 196
 197 void __exit isi_unregister(void)
 198 {
 199         phonet_proto_unregister(PN_PROTO_PHONET, &pn_dgram_proto);
 200 }