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 kiocb *iocb, struct sock *sk,
  87                         struct msghdr *msg, size_t len)
  88 {
  89         DECLARE_SOCKADDR(struct sockaddr_pn *, target, msg->msg_name);
  90         struct sk_buff *skb;
  91         int err;
  92
  93         if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_NOSIGNAL|
  94                                 MSG_CMSG_COMPAT))
  95                 return -EOPNOTSUPP;
  96
  97         if (target == NULL)
  98                 return -EDESTADDRREQ;
  99
 100         if (msg->msg_namelen < sizeof(struct sockaddr_pn))
 101                 return -EINVAL;
 102
 103         if (target->spn_family != AF_PHONET)
 104                 return -EAFNOSUPPORT;
 105
 106         skb = sock_alloc_send_skb(sk, MAX_PHONET_HEADER + len,
 107                                         msg->msg_flags & MSG_DONTWAIT, &err);
 108         if (skb == NULL)
 109                 return err;
 110         skb_reserve(skb, MAX_PHONET_HEADER);
 111
 112         err = memcpy_from_msg((void *)skb_put(skb, len), msg, len);
 113         if (err < 0) {
 114                 kfree_skb(skb);
 115                 return err;
 116         }
 117
 118         /*
 119          * Fill in the Phonet header and
 120          * finally pass the packet forwards.
 121          */
 122         err = pn_skb_send(sk, skb, target);
 123
 124         /* If ok, return len. */
 125         return (err >= 0) ? len : err;
 126 }
 127
 128 static int pn_recvmsg(struct kiocb *iocb, struct sock *sk,
 129                         struct msghdr *msg, size_t len, int noblock,
 130                         int flags, int *addr_len)
 131 {
 132         struct sk_buff *skb = NULL;
 133         struct sockaddr_pn sa;
 134         int rval = -EOPNOTSUPP;
 135         int copylen;
 136
 137         if (flags & ~(MSG_PEEK|MSG_TRUNC|MSG_DONTWAIT|MSG_NOSIGNAL|
 138                         MSG_CMSG_COMPAT))
 139                 goto out_nofree;
 140
 141         skb = skb_recv_datagram(sk, flags, noblock, &rval);
 142         if (skb == NULL)
 143                 goto out_nofree;
 144
 145         pn_skb_get_src_sockaddr(skb, &sa);
 146
 147         copylen = skb->len;
 148         if (len < copylen) {
 149                 msg->msg_flags |= MSG_TRUNC;
 150                 copylen = len;
 151         }
 152
 153         rval = skb_copy_datagram_msg(skb, 0, msg, copylen);
 154         if (rval) {
 155                 rval = -EFAULT;
 156                 goto out;
 157         }
 158
 159         rval = (flags & MSG_TRUNC) ? skb->len : copylen;
 160
 161         if (msg->msg_name != NULL) {
 162                 __sockaddr_check_size(sizeof(sa));
 163                 memcpy(msg->msg_name, &sa, sizeof(sa));
 164                 *addr_len = sizeof(sa);
 165         }
 166
 167 out:
 168         skb_free_datagram(sk, skb);
 169
 170 out_nofree:
 171         return rval;
 172 }
 173
 174 /* Queue an skb for a sock. */
 175 static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb)
 176 {
 177         int err = sock_queue_rcv_skb(sk, skb);
 178
 179         if (err < 0)
 180                 kfree_skb(skb);
 181         return err ? NET_RX_DROP : NET_RX_SUCCESS;
 182 }
 183
 184 /* Module registration */
 185 static struct proto pn_proto = {
 186         .close          = pn_sock_close,
 187         .ioctl          = pn_ioctl,
 188         .init           = pn_init,
 189         .sendmsg        = pn_sendmsg,
 190         .recvmsg        = pn_recvmsg,
 191         .backlog_rcv    = pn_backlog_rcv,
 192         .hash           = pn_sock_hash,
 193         .unhash         = pn_sock_unhash,
 194         .get_port       = pn_sock_get_port,
 195         .obj_size       = sizeof(struct pn_sock),
 196         .owner          = THIS_MODULE,
 197         .name           = "PHONET",
 198 };
 199
 200 static struct phonet_protocol pn_dgram_proto = {
 201         .ops            = &phonet_dgram_ops,
 202         .prot           = &pn_proto,
 203         .sock_type      = SOCK_DGRAM,
 204 };
 205
 206 int __init isi_register(void)
 207 {
 208         return phonet_proto_register(PN_PROTO_PHONET, &pn_dgram_proto);
 209 }
 210
 211 void __exit isi_unregister(void)
 212 {
 213         phonet_proto_unregister(PN_PROTO_PHONET, &pn_dgram_proto);
 214 }