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