Phonet: PF_PHONET protocol family support

This is the basis for the Phonet protocol families, and introduces
the ETH_P_PHONET packet type and the PF_PHONET socket family.

Signed-off-by: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 216 insertions, 0 deletions

diff --git a/net/phonet/af_phonet.c b/net/phonet/af_phonet.c
new file mode 100644
index 000000000000..0cfea9bc994a
--- /dev/null
+++ b/net/phonet/af_phonet.c
@@ -0,0 +1,216 @@
+/*
+ * 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>
+
+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 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;
+                default:
+                        return -EPROTONOSUPPORT;
+                }
+        }
+
+        pnp = phonet_proto_get(protocol);
+        if (pnp == NULL)
+                return -EPROTONOSUPPORT;
+        if (sock->type != pnp->sock_type) {
+                err = -EPROTONOSUPPORT;
+                goto out;
+        }
+
+        /* TODO: create and init the struct sock */
+        err = -EPROTONOSUPPORT;
+
+out:
+        phonet_proto_put(pnp);
+        return err;
+}
+
+static struct net_proto_family phonet_proto_family = {
+        .family = AF_PHONET,
+        .create = pn_socket_create,
+        .owner = THIS_MODULE,
+};
+
+/* 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 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 */
+
+        /* TODO: put packets to sockets backlog */
+
+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;
+        }
+
+        dev_add_pack(&phonet_packet_type);
+        return 0;
+}
+
+static void __exit phonet_exit(void)
+{
+        sock_unregister(AF_PHONET);
+        dev_remove_pack(&phonet_packet_type);
+}
+
+module_init(phonet_init);
+module_exit(phonet_exit);
+MODULE_DESCRIPTION("Phonet protocol stack for Linux");
+MODULE_LICENSE("GPL");