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