net/phonet/datagram.c

   1 /*
   2  * File: datagram.c
   3  *
   4  * Datagram (ISI) Phonet sockets
   5  *
   6  * Copyright (C) 2008 Nokia Corporation.
   7  *
   8  * Authors: Sakari Ailus <sakari.ailus@nokia.com>
   9  *          Rémi Denis-Courmont
  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/slab.h>
  28 #include <linux/socket.h>
  29 #include <asm/ioctls.h>
  30 #include <net/sock.h>
  31
  32 #include <linux/phonet.h>
  33 #include <linux/export.h>
  34 #include <net/phonet/phonet.h>
  35
  36 static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb);
  37
  38 /* associated socket ceases to exist */
  39 static void pn_sock_close(struct sock *sk, long timeout)
  40 {
  41         sk_common_release(sk);
  42 }
  43
  44 static int pn_ioctl(struct sock *sk, int cmd, unsigned long arg)
  45 {
  46         struct sk_buff *skb;
  47         int answ;
  48
  49         switch (cmd) {
  50         case SIOCINQ:
  51                 lock_sock(sk);
  52                 skb = skb_peek(&sk->sk_receive_queue);
  53                 answ = skb ? skb->len : 0;
  54                 release_sock(sk);
  55                 return put_user(answ, (int __user *)arg);
  56
  57         case SIOCPNADDRESOURCE:
  58         case SIOCPNDELRESOURCE: {
  59                         u32 res;
  60                         if (get_user(res, (u32 __user *)arg))
  61                                 return -EFAULT;
  62                         if (res >= 256)
  63                                 return -EINVAL;
  64                         if (cmd == SIOCPNADDRESOURCE)
  65                                 return pn_sock_bind_res(sk, res);
  66                         else
  67                                 return pn_sock_unbind_res(sk, res);
  68                 }
  69         }
  70
  71         return -ENOIOCTLCMD;
  72 }
  73
  74 /* Destroy socket. All references are gone. */
  75 static void pn_destruct(struct sock *sk)
  76 {
  77         skb_queue_purge(&sk->sk_receive_queue);
  78 }
  79
  80 static int pn_init(struct sock *sk)
  81 {
  82         sk->sk_destruct = pn_destruct;
  83         return 0;
  84 }
  85
  86 static int pn_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
  87 {
  88         DECLARE_SOCKADDR(struct sockaddr_pn *, target, msg->msg_name);
  89         struct sk_buff *skb;
  90         int err;
  91
  92         if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_NOSIGNAL|
  93                                 MSG_CMSG_COMPAT))
  94                 return -EOPNOTSUPP;
  95
  96         if (target == NULL)
  97                 return -EDESTADDRREQ;
  98
  99         if (msg->msg_namelen < sizeof(struct sockaddr_pn))
 100                 return -EINVAL;
 101
 102         if (target->spn_family != AF_PHONET)
 103                 return -EAFNOSUPPORT;
 104
 105         skb = sock_alloc_send_skb(sk, MAX_PHONET_HEADER + len,
 106                                         msg->msg_flags & MSG_DONTWAIT, &err);
 107         if (skb == NULL)
 108                 return err;
 109         skb_reserve(skb, MAX_PHONET_HEADER);
 110
 111         err = memcpy_from_msg((void *)skb_put(skb, len), msg, len);
 112         if (err < 0) {
 113                 kfree_skb(skb);
 114                 return err;
 115         }
 116
 117         /*
 118          * Fill in the Phonet header and
 119          * finally pass the packet forwards.
 120          */
 121         err = pn_skb_send(sk, skb, target);
 122
 123         /* If ok, return len. */
 124         return (err >= 0) ? len : err;
 125 }
 126
 127 static int pn_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 128                       int noblock, int flags, int *addr_len)
 129 {
 130         struct sk_buff *skb = NULL;
 131         struct sockaddr_pn sa;
 132         int rval = -EOPNOTSUPP;
 133         int copylen;
 134
 135         if (flags & ~(MSG_PEEK|MSG_TRUNC|MSG_DONTWAIT|MSG_NOSIGNAL|
 136                         MSG_CMSG_COMPAT))
 137                 goto out_nofree;
 138
 139         skb = skb_recv_datagram(sk, flags, noblock, &rval);
 140         if (skb == NULL)
 141                 goto out_nofree;
 142
 143         pn_skb_get_src_sockaddr(skb, &sa);
 144
 145         copylen = skb->len;
 146         if (len < copylen) {
 147                 msg->msg_flags |= MSG_TRUNC;
 148                 copylen = len;
 149         }
 150
 151         rval = skb_copy_datagram_msg(skb, 0, msg, copylen);
 152         if (rval) {
 153                 rval = -EFAULT;
 154                 goto out;
 155         }
 156
 157         rval = (flags & MSG_TRUNC) ? skb->len : copylen;
 158
 159         if (msg->msg_name != NULL) {
 160                 __sockaddr_check_size(sizeof(sa));
 161                 memcpy(msg->msg_name, &sa, sizeof(sa));
 162                 *addr_len = sizeof(sa);
 163         }
 164
 165 out:
 166         skb_free_datagram(sk, skb);
 167
 168 out_nofree:
 169         return rval;
 170 }
 171
 172 /* Queue an skb for a sock. */
 173 static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb)
 174 {
 175         int err = sock_queue_rcv_skb(sk, skb);
 176
 177         if (err < 0)
 178                 kfree_skb(skb);
 179         return err ? NET_RX_DROP : NET_RX_SUCCESS;
 180 }
 181
 182 /* Module registration */
 183 static struct proto pn_proto = {
 184         .close          = pn_sock_close,
 185         .ioctl          = pn_ioctl,
 186         .init           = pn_init,
 187         .sendmsg        = pn_sendmsg,
 188         .recvmsg        = pn_recvmsg,
 189         .backlog_rcv    = pn_backlog_rcv,
 190         .hash           = pn_sock_hash,
 191         .unhash         = pn_sock_unhash,
 192         .get_port       = pn_sock_get_port,
 193         .obj_size       = sizeof(struct pn_sock),
 194         .owner          = THIS_MODULE,
 195         .name           = "PHONET",
 196 };
 197
 198 static const struct phonet_protocol pn_dgram_proto = {
 199         .ops            = &phonet_dgram_ops,
 200         .prot           = &pn_proto,
 201         .sock_type      = SOCK_DGRAM,
 202 };
 203
 204 int __init isi_register(void)
 205 {
 206         return phonet_proto_register(PN_PROTO_PHONET, &pn_dgram_proto);
 207 }
 208
 209 void __exit isi_unregister(void)
 210 {
 211         phonet_proto_unregister(PN_PROTO_PHONET, &pn_dgram_proto);
 212 }