![Rémi Denis-Courmont](/assets/img/avatar_default.png)
Phonet assumes that packets are never dropped. We try our best to avoid this situation. But lets return ENOBUFS if queueing to the network device fails so that the caller knows things went wrong. Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com> Signed-off-by: David S. Miller <davem@davemloft.net>
549 lines
13 KiB
C
549 lines
13 KiB
C
/*
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* File: af_phonet.c
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*
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* Phonet protocols family
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*
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* Copyright (C) 2008 Nokia Corporation.
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*
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* Contact: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
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* Original author: Sakari Ailus <sakari.ailus@nokia.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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* 02110-1301 USA
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <asm/unaligned.h>
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#include <net/sock.h>
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#include <linux/if_phonet.h>
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#include <linux/phonet.h>
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#include <net/phonet/phonet.h>
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#include <net/phonet/pn_dev.h>
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/* Transport protocol registration */
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static struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly;
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static struct phonet_protocol *phonet_proto_get(unsigned int protocol)
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{
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struct phonet_protocol *pp;
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if (protocol >= PHONET_NPROTO)
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return NULL;
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rcu_read_lock();
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pp = rcu_dereference(proto_tab[protocol]);
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if (pp && !try_module_get(pp->prot->owner))
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pp = NULL;
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rcu_read_unlock();
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return pp;
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}
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static inline void phonet_proto_put(struct phonet_protocol *pp)
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{
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module_put(pp->prot->owner);
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}
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/* protocol family functions */
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static int pn_socket_create(struct net *net, struct socket *sock, int protocol,
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int kern)
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{
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struct sock *sk;
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struct pn_sock *pn;
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struct phonet_protocol *pnp;
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int err;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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if (protocol == 0) {
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/* Default protocol selection */
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switch (sock->type) {
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case SOCK_DGRAM:
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protocol = PN_PROTO_PHONET;
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break;
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case SOCK_SEQPACKET:
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protocol = PN_PROTO_PIPE;
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break;
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default:
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return -EPROTONOSUPPORT;
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}
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}
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pnp = phonet_proto_get(protocol);
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if (pnp == NULL &&
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request_module("net-pf-%d-proto-%d", PF_PHONET, protocol) == 0)
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pnp = phonet_proto_get(protocol);
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if (pnp == NULL)
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return -EPROTONOSUPPORT;
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if (sock->type != pnp->sock_type) {
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err = -EPROTONOSUPPORT;
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goto out;
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}
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sk = sk_alloc(net, PF_PHONET, GFP_KERNEL, pnp->prot);
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if (sk == NULL) {
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err = -ENOMEM;
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goto out;
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}
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sock_init_data(sock, sk);
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sock->state = SS_UNCONNECTED;
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sock->ops = pnp->ops;
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sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
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sk->sk_protocol = protocol;
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pn = pn_sk(sk);
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pn->sobject = 0;
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pn->dobject = 0;
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pn->resource = 0;
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sk->sk_prot->init(sk);
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err = 0;
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out:
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phonet_proto_put(pnp);
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return err;
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}
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static const struct net_proto_family phonet_proto_family = {
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.family = PF_PHONET,
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.create = pn_socket_create,
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.owner = THIS_MODULE,
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};
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/* Phonet device header operations */
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static int pn_header_create(struct sk_buff *skb, struct net_device *dev,
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unsigned short type, const void *daddr,
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const void *saddr, unsigned len)
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{
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u8 *media = skb_push(skb, 1);
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if (type != ETH_P_PHONET)
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return -1;
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if (!saddr)
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saddr = dev->dev_addr;
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*media = *(const u8 *)saddr;
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return 1;
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}
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static int pn_header_parse(const struct sk_buff *skb, unsigned char *haddr)
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{
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const u8 *media = skb_mac_header(skb);
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*haddr = *media;
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return 1;
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}
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struct header_ops phonet_header_ops = {
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.create = pn_header_create,
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.parse = pn_header_parse,
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};
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EXPORT_SYMBOL(phonet_header_ops);
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/*
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* Prepends an ISI header and sends a datagram.
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*/
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static int pn_send(struct sk_buff *skb, struct net_device *dev,
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u16 dst, u16 src, u8 res, u8 irq)
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{
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struct phonethdr *ph;
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int err;
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if (skb->len + 2 > 0xffff /* Phonet length field limit */ ||
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skb->len + sizeof(struct phonethdr) > dev->mtu) {
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err = -EMSGSIZE;
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goto drop;
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}
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/* Broadcast sending is not implemented */
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if (pn_addr(dst) == PNADDR_BROADCAST) {
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err = -EOPNOTSUPP;
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goto drop;
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}
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skb_reset_transport_header(skb);
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WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */
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skb_push(skb, sizeof(struct phonethdr));
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skb_reset_network_header(skb);
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ph = pn_hdr(skb);
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ph->pn_rdev = pn_dev(dst);
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ph->pn_sdev = pn_dev(src);
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ph->pn_res = res;
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ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph));
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ph->pn_robj = pn_obj(dst);
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ph->pn_sobj = pn_obj(src);
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skb->protocol = htons(ETH_P_PHONET);
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skb->priority = 0;
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skb->dev = dev;
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if (skb->pkt_type == PACKET_LOOPBACK) {
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skb_reset_mac_header(skb);
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skb_orphan(skb);
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err = (irq ? netif_rx(skb) : netif_rx_ni(skb)) ? -ENOBUFS : 0;
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} else {
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err = dev_hard_header(skb, dev, ntohs(skb->protocol),
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NULL, NULL, skb->len);
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if (err < 0) {
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err = -EHOSTUNREACH;
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goto drop;
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}
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err = dev_queue_xmit(skb);
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if (unlikely(err > 0))
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err = net_xmit_errno(err);
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}
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return err;
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drop:
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kfree_skb(skb);
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return err;
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}
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static int pn_raw_send(const void *data, int len, struct net_device *dev,
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u16 dst, u16 src, u8 res)
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{
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struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC);
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if (skb == NULL)
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return -ENOMEM;
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if (phonet_address_lookup(dev_net(dev), pn_addr(dst)) == 0)
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skb->pkt_type = PACKET_LOOPBACK;
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skb_reserve(skb, MAX_PHONET_HEADER);
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__skb_put(skb, len);
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skb_copy_to_linear_data(skb, data, len);
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return pn_send(skb, dev, dst, src, res, 1);
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}
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/*
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* Create a Phonet header for the skb and send it out. Returns
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* non-zero error code if failed. The skb is freed then.
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*/
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int pn_skb_send(struct sock *sk, struct sk_buff *skb,
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const struct sockaddr_pn *target)
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{
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struct net *net = sock_net(sk);
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struct net_device *dev;
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struct pn_sock *pn = pn_sk(sk);
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int err;
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u16 src, dst;
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u8 daddr, saddr, res;
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src = pn->sobject;
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if (target != NULL) {
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dst = pn_sockaddr_get_object(target);
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res = pn_sockaddr_get_resource(target);
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} else {
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dst = pn->dobject;
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res = pn->resource;
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}
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daddr = pn_addr(dst);
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err = -EHOSTUNREACH;
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if (sk->sk_bound_dev_if)
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dev = dev_get_by_index(net, sk->sk_bound_dev_if);
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else if (phonet_address_lookup(net, daddr) == 0) {
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dev = phonet_device_get(net);
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skb->pkt_type = PACKET_LOOPBACK;
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} else if (dst == 0) {
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/* Resource routing (small race until phonet_rcv()) */
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struct sock *sk = pn_find_sock_by_res(net, res);
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if (sk) {
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sock_put(sk);
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dev = phonet_device_get(net);
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skb->pkt_type = PACKET_LOOPBACK;
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} else
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dev = phonet_route_output(net, daddr);
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} else
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dev = phonet_route_output(net, daddr);
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if (!dev || !(dev->flags & IFF_UP))
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goto drop;
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saddr = phonet_address_get(dev, daddr);
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if (saddr == PN_NO_ADDR)
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goto drop;
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if (!pn_addr(src))
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src = pn_object(saddr, pn_obj(src));
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err = pn_send(skb, dev, dst, src, res, 0);
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dev_put(dev);
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return err;
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drop:
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kfree_skb(skb);
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if (dev)
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dev_put(dev);
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return err;
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}
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EXPORT_SYMBOL(pn_skb_send);
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/* Do not send an error message in response to an error message */
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static inline int can_respond(struct sk_buff *skb)
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{
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const struct phonethdr *ph;
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const struct phonetmsg *pm;
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u8 submsg_id;
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if (!pskb_may_pull(skb, 3))
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return 0;
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ph = pn_hdr(skb);
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if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5))
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return 0;
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if (ph->pn_res == PN_COMMGR) /* indications */
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return 0;
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ph = pn_hdr(skb); /* re-acquires the pointer */
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pm = pn_msg(skb);
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if (pm->pn_msg_id != PN_COMMON_MESSAGE)
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return 1;
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submsg_id = (ph->pn_res == PN_PREFIX)
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? pm->pn_e_submsg_id : pm->pn_submsg_id;
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if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP &&
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pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP)
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return 1;
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return 0;
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}
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static int send_obj_unreachable(struct sk_buff *rskb)
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{
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const struct phonethdr *oph = pn_hdr(rskb);
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const struct phonetmsg *opm = pn_msg(rskb);
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struct phonetmsg resp;
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memset(&resp, 0, sizeof(resp));
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resp.pn_trans_id = opm->pn_trans_id;
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resp.pn_msg_id = PN_COMMON_MESSAGE;
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if (oph->pn_res == PN_PREFIX) {
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resp.pn_e_res_id = opm->pn_e_res_id;
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resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
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resp.pn_e_orig_msg_id = opm->pn_msg_id;
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resp.pn_e_status = 0;
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} else {
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resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
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resp.pn_orig_msg_id = opm->pn_msg_id;
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resp.pn_status = 0;
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}
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return pn_raw_send(&resp, sizeof(resp), rskb->dev,
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pn_object(oph->pn_sdev, oph->pn_sobj),
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pn_object(oph->pn_rdev, oph->pn_robj),
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oph->pn_res);
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}
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static int send_reset_indications(struct sk_buff *rskb)
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{
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struct phonethdr *oph = pn_hdr(rskb);
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static const u8 data[4] = {
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0x00 /* trans ID */, 0x10 /* subscribe msg */,
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0x00 /* subscription count */, 0x00 /* dummy */
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};
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return pn_raw_send(data, sizeof(data), rskb->dev,
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pn_object(oph->pn_sdev, 0x00),
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pn_object(oph->pn_rdev, oph->pn_robj),
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PN_COMMGR);
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}
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/* packet type functions */
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/*
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* Stuff received packets to associated sockets.
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* On error, returns non-zero and releases the skb.
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*/
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static int phonet_rcv(struct sk_buff *skb, struct net_device *dev,
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struct packet_type *pkttype,
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struct net_device *orig_dev)
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{
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struct net *net = dev_net(dev);
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struct phonethdr *ph;
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struct sockaddr_pn sa;
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u16 len;
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/* check we have at least a full Phonet header */
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if (!pskb_pull(skb, sizeof(struct phonethdr)))
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goto out;
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/* check that the advertised length is correct */
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ph = pn_hdr(skb);
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len = get_unaligned_be16(&ph->pn_length);
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if (len < 2)
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goto out;
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len -= 2;
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if ((len > skb->len) || pskb_trim(skb, len))
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goto out;
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skb_reset_transport_header(skb);
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pn_skb_get_dst_sockaddr(skb, &sa);
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/* check if this is broadcasted */
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if (pn_sockaddr_get_addr(&sa) == PNADDR_BROADCAST) {
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pn_deliver_sock_broadcast(net, skb);
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goto out;
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}
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/* resource routing */
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if (pn_sockaddr_get_object(&sa) == 0) {
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struct sock *sk = pn_find_sock_by_res(net, sa.spn_resource);
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if (sk)
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return sk_receive_skb(sk, skb, 0);
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}
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/* check if we are the destination */
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if (phonet_address_lookup(net, pn_sockaddr_get_addr(&sa)) == 0) {
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/* Phonet packet input */
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struct sock *sk = pn_find_sock_by_sa(net, &sa);
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if (sk)
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return sk_receive_skb(sk, skb, 0);
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if (can_respond(skb)) {
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send_obj_unreachable(skb);
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send_reset_indications(skb);
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}
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} else if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
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goto out; /* Race between address deletion and loopback */
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else {
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/* Phonet packet routing */
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struct net_device *out_dev;
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out_dev = phonet_route_output(net, pn_sockaddr_get_addr(&sa));
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if (!out_dev) {
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LIMIT_NETDEBUG(KERN_WARNING"No Phonet route to %02X\n",
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pn_sockaddr_get_addr(&sa));
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goto out;
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}
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__skb_push(skb, sizeof(struct phonethdr));
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skb->dev = out_dev;
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if (out_dev == dev) {
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LIMIT_NETDEBUG(KERN_ERR"Phonet loop to %02X on %s\n",
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pn_sockaddr_get_addr(&sa), dev->name);
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goto out_dev;
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}
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/* Some drivers (e.g. TUN) do not allocate HW header space */
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if (skb_cow_head(skb, out_dev->hard_header_len))
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goto out_dev;
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if (dev_hard_header(skb, out_dev, ETH_P_PHONET, NULL, NULL,
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skb->len) < 0)
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goto out_dev;
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dev_queue_xmit(skb);
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dev_put(out_dev);
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return NET_RX_SUCCESS;
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out_dev:
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dev_put(out_dev);
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}
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out:
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kfree_skb(skb);
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return NET_RX_DROP;
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}
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static struct packet_type phonet_packet_type __read_mostly = {
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.type = cpu_to_be16(ETH_P_PHONET),
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.func = phonet_rcv,
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};
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static DEFINE_MUTEX(proto_tab_lock);
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int __init_or_module phonet_proto_register(unsigned int protocol,
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struct phonet_protocol *pp)
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{
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int err = 0;
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if (protocol >= PHONET_NPROTO)
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return -EINVAL;
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err = proto_register(pp->prot, 1);
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if (err)
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return err;
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mutex_lock(&proto_tab_lock);
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if (proto_tab[protocol])
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err = -EBUSY;
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else
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rcu_assign_pointer(proto_tab[protocol], pp);
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mutex_unlock(&proto_tab_lock);
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return err;
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}
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EXPORT_SYMBOL(phonet_proto_register);
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void phonet_proto_unregister(unsigned int protocol, struct phonet_protocol *pp)
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{
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mutex_lock(&proto_tab_lock);
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BUG_ON(proto_tab[protocol] != pp);
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rcu_assign_pointer(proto_tab[protocol], NULL);
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mutex_unlock(&proto_tab_lock);
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synchronize_rcu();
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proto_unregister(pp->prot);
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}
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EXPORT_SYMBOL(phonet_proto_unregister);
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/* Module registration */
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static int __init phonet_init(void)
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{
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int err;
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err = phonet_device_init();
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if (err)
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return err;
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|
pn_sock_init();
|
|
err = sock_register(&phonet_proto_family);
|
|
if (err) {
|
|
printk(KERN_ALERT
|
|
"phonet protocol family initialization failed\n");
|
|
goto err_sock;
|
|
}
|
|
|
|
dev_add_pack(&phonet_packet_type);
|
|
phonet_sysctl_init();
|
|
|
|
err = isi_register();
|
|
if (err)
|
|
goto err;
|
|
return 0;
|
|
|
|
err:
|
|
phonet_sysctl_exit();
|
|
sock_unregister(PF_PHONET);
|
|
dev_remove_pack(&phonet_packet_type);
|
|
err_sock:
|
|
phonet_device_exit();
|
|
return err;
|
|
}
|
|
|
|
static void __exit phonet_exit(void)
|
|
{
|
|
isi_unregister();
|
|
phonet_sysctl_exit();
|
|
sock_unregister(PF_PHONET);
|
|
dev_remove_pack(&phonet_packet_type);
|
|
phonet_device_exit();
|
|
}
|
|
|
|
module_init(phonet_init);
|
|
module_exit(phonet_exit);
|
|
MODULE_DESCRIPTION("Phonet protocol stack for Linux");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_NETPROTO(PF_PHONET);
|