linux/net/phonet/af_phonet.c
Rémi Denis-Courmont 9641458d3e Phonet: Pipe End Point for Phonet Pipes protocol
This protocol provides some connection handling and negotiated
congestion control. Nokia cellular modems use it for bulk transfers.
It provides packet boundaries (hence SOCK_SEQPACKET). Congestion
control is per packet rather per byte, so we do not re-use the
generic socket memory accounting.

Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-05 11:15:13 -07:00

478 lines
11 KiB
C

/*
* File: af_phonet.c
*
* Phonet protocols family
*
* Copyright (C) 2008 Nokia Corporation.
*
* Contact: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
* Original author: Sakari Ailus <sakari.ailus@nokia.com>
*
* 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 <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>
static struct net_proto_family phonet_proto_family;
static struct phonet_protocol *phonet_proto_get(int protocol);
static inline void phonet_proto_put(struct phonet_protocol *pp);
/* protocol family functions */
static int pn_socket_create(struct net *net, struct socket *sock, int protocol)
{
struct sock *sk;
struct pn_sock *pn;
struct phonet_protocol *pnp;
int err;
if (net != &init_net)
return -EAFNOSUPPORT;
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);
#ifdef CONFIG_KMOD
if (pnp == NULL &&
request_module("net-pf-%d-proto-%d", PF_PHONET, protocol) == 0)
pnp = phonet_proto_get(protocol);
#endif
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->resource = 0;
sk->sk_prot->init(sk);
err = 0;
out:
phonet_proto_put(pnp);
return err;
}
static 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 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 would overflow */
err = -EMSGSIZE;
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 (pn_addr(src) == pn_addr(dst)) {
skb_reset_mac_header(skb);
skb->pkt_type = PACKET_LOOPBACK;
skb_orphan(skb);
if (irq)
netif_rx(skb);
else
netif_rx_ni(skb);
err = 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);
}
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;
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_device *dev;
struct pn_sock *pn = pn_sk(sk);
int err;
u16 src;
u8 daddr = pn_sockaddr_get_addr(target), saddr = PN_NO_ADDR;
err = -EHOSTUNREACH;
if (sk->sk_bound_dev_if)
dev = dev_get_by_index(sock_net(sk), sk->sk_bound_dev_if);
else
dev = phonet_device_get(sock_net(sk));
if (!dev || !(dev->flags & IFF_UP))
goto drop;
saddr = phonet_address_get(dev, daddr);
if (saddr == PN_NO_ADDR)
goto drop;
src = pn->sobject;
if (!pn_addr(src))
src = pn_object(saddr, pn_obj(src));
err = pn_send(skb, dev, pn_sockaddr_get_object(target),
src, pn_sockaddr_get_resource(target), 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 (phonet_address_get(skb->dev, ph->pn_rdev) != ph->pn_rdev)
return 0; /* we are not the destination */
if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5))
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), 0x10);
}
/* 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 phonethdr *ph;
struct sock *sk;
struct sockaddr_pn sa;
u16 len;
if (dev_net(dev) != &init_net)
goto out;
/* 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);
if (pn_sockaddr_get_addr(&sa) == 0)
goto out; /* currently, we cannot be device 0 */
sk = pn_find_sock_by_sa(&sa);
if (sk == NULL) {
if (can_respond(skb)) {
send_obj_unreachable(skb);
send_reset_indications(skb);
}
goto out;
}
/* Push data to the socket (or other sockets connected to it). */
return sk_receive_skb(sk, skb, 0);
out:
kfree_skb(skb);
return NET_RX_DROP;
}
static struct packet_type phonet_packet_type = {
.type = __constant_htons(ETH_P_PHONET),
.dev = NULL,
.func = phonet_rcv,
};
/* Transport protocol registration */
static struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly;
static DEFINE_SPINLOCK(proto_tab_lock);
int __init_or_module phonet_proto_register(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;
spin_lock(&proto_tab_lock);
if (proto_tab[protocol])
err = -EBUSY;
else
proto_tab[protocol] = pp;
spin_unlock(&proto_tab_lock);
return err;
}
EXPORT_SYMBOL(phonet_proto_register);
void phonet_proto_unregister(int protocol, struct phonet_protocol *pp)
{
spin_lock(&proto_tab_lock);
BUG_ON(proto_tab[protocol] != pp);
proto_tab[protocol] = NULL;
spin_unlock(&proto_tab_lock);
proto_unregister(pp->prot);
}
EXPORT_SYMBOL(phonet_proto_unregister);
static struct phonet_protocol *phonet_proto_get(int protocol)
{
struct phonet_protocol *pp;
if (protocol >= PHONET_NPROTO)
return NULL;
spin_lock(&proto_tab_lock);
pp = proto_tab[protocol];
if (pp && !try_module_get(pp->prot->owner))
pp = NULL;
spin_unlock(&proto_tab_lock);
return pp;
}
static inline void phonet_proto_put(struct phonet_protocol *pp)
{
module_put(pp->prot->owner);
}
/* Module registration */
static int __init phonet_init(void)
{
int err;
err = sock_register(&phonet_proto_family);
if (err) {
printk(KERN_ALERT
"phonet protocol family initialization failed\n");
return err;
}
phonet_device_init();
dev_add_pack(&phonet_packet_type);
phonet_netlink_register();
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);
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);