Phonet: implement GPRS virtual interface over PEP socket

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

4 files changed, 502 insertions, 16 deletions

diff --git a/net/phonet/Makefile b/net/phonet/Makefile
index 505df2a04a85..d62bbba649b3 100644
--- a/net/phonet/Makefile
+++ b/net/phonet/Makefile
@@ -8,4 +8,4 @@ phonet-objs := \
         sysctl.o \
         af_phonet.o
 
-pn_pep-objs := pep.o
+pn_pep-objs := pep.o pep-gprs.o
diff --git a/net/phonet/pep-gprs.c b/net/phonet/pep-gprs.c
new file mode 100644
index 000000000000..9978afbd9f2a
--- /dev/null
+++ b/net/phonet/pep-gprs.c
@@ -0,0 +1,347 @@
+/*
+ * File: pep-gprs.c
+ *
+ * GPRS over Phonet pipe end point socket
+ *
+ * Copyright (C) 2008 Nokia Corporation.
+ *
+ * Author: Rémi Denis-Courmont <remi.denis-courmont@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/netdevice.h>
+#include <linux/if_ether.h>
+#include <linux/if_arp.h>
+#include <net/sock.h>
+
+#include <linux/if_phonet.h>
+#include <net/tcp_states.h>
+#include <net/phonet/gprs.h>
+
+#define GPRS_DEFAULT_MTU 1400
+
+struct gprs_dev {
+        struct sock             *sk;
+        void                    (*old_state_change)(struct sock *);
+        void                    (*old_data_ready)(struct sock *, int);
+        void                    (*old_write_space)(struct sock *);
+
+        struct net_device       *net;
+        struct net_device_stats stats;
+
+        struct sk_buff_head     tx_queue;
+        struct work_struct      tx_work;
+        spinlock_t              tx_lock;
+        unsigned                tx_max;
+};
+
+static int gprs_type_trans(struct sk_buff *skb)
+{
+        const u8 *pvfc;
+        u8 buf;
+
+        pvfc = skb_header_pointer(skb, 0, 1, &buf);
+        if (!pvfc)
+                return 0;
+        /* Look at IP version field */
+        switch (*pvfc >> 4) {
+        case 4:
+                return htons(ETH_P_IP);
+        case 6:
+                return htons(ETH_P_IPV6);
+        }
+        return 0;
+}
+
+/*
+ * Socket callbacks
+ */
+
+static void gprs_state_change(struct sock *sk)
+{
+        struct gprs_dev *dev = sk->sk_user_data;
+
+        if (sk->sk_state == TCP_CLOSE_WAIT) {
+                netif_stop_queue(dev->net);
+                netif_carrier_off(dev->net);
+        }
+}
+
+static int gprs_recv(struct gprs_dev *dev, struct sk_buff *skb)
+{
+        int err = 0;
+        u16 protocol = gprs_type_trans(skb);
+
+        if (!protocol) {
+                err = -EINVAL;
+                goto drop;
+        }
+
+        if (likely(skb_headroom(skb) & 3)) {
+                struct sk_buff *rskb, *fs;
+                int flen = 0;
+
+                /* Phonet Pipe data header is misaligned (3 bytes),
+                 * so wrap the IP packet as a single fragment of an head-less
+                 * socket buffer. The network stack will pull what it needs,
+                 * but at least, the whole IP payload is not memcpy'd. */
+                rskb = netdev_alloc_skb(dev->net, 0);
+                if (!rskb) {
+                        err = -ENOBUFS;
+                        goto drop;
+                }
+                skb_shinfo(rskb)->frag_list = skb;
+                rskb->len += skb->len;
+                rskb->data_len += rskb->len;
+                rskb->truesize += rskb->len;
+
+                /* Avoid nested fragments */
+                for (fs = skb_shinfo(skb)->frag_list; fs; fs = fs->next)
+                        flen += fs->len;
+                skb->next = skb_shinfo(skb)->frag_list;
+                skb_shinfo(skb)->frag_list = NULL;
+                skb->len -= flen;
+                skb->data_len -= flen;
+                skb->truesize -= flen;
+
+                skb = rskb;
+        }
+
+        skb->protocol = protocol;
+        skb_reset_mac_header(skb);
+        skb->dev = dev->net;
+
+        if (likely(dev->net->flags & IFF_UP)) {
+                dev->stats.rx_packets++;
+                dev->stats.rx_bytes += skb->len;
+                netif_rx(skb);
+                skb = NULL;
+        } else
+                err = -ENODEV;
+
+drop:
+        if (skb) {
+                dev_kfree_skb(skb);
+                dev->stats.rx_dropped++;
+        }
+        return err;
+}
+
+static void gprs_data_ready(struct sock *sk, int len)
+{
+        struct gprs_dev *dev = sk->sk_user_data;
+        struct sk_buff *skb;
+
+        while ((skb = pep_read(sk)) != NULL) {
+                skb_orphan(skb);
+                gprs_recv(dev, skb);
+        }
+}
+
+static void gprs_write_space(struct sock *sk)
+{
+        struct gprs_dev *dev = sk->sk_user_data;
+        unsigned credits = pep_writeable(sk);
+
+        spin_lock_bh(&dev->tx_lock);
+        dev->tx_max = credits;
+        if (credits > skb_queue_len(&dev->tx_queue))
+                netif_wake_queue(dev->net);
+        spin_unlock_bh(&dev->tx_lock);
+}
+
+/*
+ * Network device callbacks
+ */
+
+static int gprs_xmit(struct sk_buff *skb, struct net_device *net)
+{
+        struct gprs_dev *dev = netdev_priv(net);
+
+        switch (skb->protocol) {
+        case  htons(ETH_P_IP):
+        case  htons(ETH_P_IPV6):
+                break;
+        default:
+                dev_kfree_skb(skb);
+                return 0;
+        }
+
+        spin_lock(&dev->tx_lock);
+        if (likely(skb_queue_len(&dev->tx_queue) < dev->tx_max)) {
+                skb_queue_tail(&dev->tx_queue, skb);
+                skb = NULL;
+        }
+        if (skb_queue_len(&dev->tx_queue) >= dev->tx_max)
+                netif_stop_queue(net);
+        spin_unlock(&dev->tx_lock);
+
+        schedule_work(&dev->tx_work);
+        if (unlikely(skb))
+                dev_kfree_skb(skb);
+        return 0;
+}
+
+static void gprs_tx(struct work_struct *work)
+{
+        struct gprs_dev *dev = container_of(work, struct gprs_dev, tx_work);
+        struct sock *sk = dev->sk;
+        struct sk_buff *skb;
+
+        while ((skb = skb_dequeue(&dev->tx_queue)) != NULL) {
+                int err;
+
+                dev->stats.tx_bytes += skb->len;
+                dev->stats.tx_packets++;
+
+                skb_orphan(skb);
+                skb_set_owner_w(skb, sk);
+
+                lock_sock(sk);
+                err = pep_write(sk, skb);
+                if (err) {
+                        LIMIT_NETDEBUG(KERN_WARNING"%s: TX error (%d)\n",
+                                        dev->net->name, err);
+                        dev->stats.tx_aborted_errors++;
+                        dev->stats.tx_errors++;
+                }
+                release_sock(sk);
+        }
+
+        lock_sock(sk);
+        gprs_write_space(sk);
+        release_sock(sk);
+}
+
+static int gprs_set_mtu(struct net_device *net, int new_mtu)
+{
+        if ((new_mtu < 576) || (new_mtu > (PHONET_MAX_MTU - 11)))
+                return -EINVAL;
+
+        net->mtu = new_mtu;
+        return 0;
+}
+
+static struct net_device_stats *gprs_get_stats(struct net_device *net)
+{
+        struct gprs_dev *dev = netdev_priv(net);
+
+        return &dev->stats;
+}
+
+static void gprs_setup(struct net_device *net)
+{
+        net->features           = NETIF_F_FRAGLIST;
+        net->type               = ARPHRD_NONE;
+        net->flags              = IFF_POINTOPOINT | IFF_NOARP;
+        net->mtu                = GPRS_DEFAULT_MTU;
+        net->hard_header_len    = 0;
+        net->addr_len           = 0;
+        net->tx_queue_len       = 10;
+
+        net->destructor         = free_netdev;
+        net->hard_start_xmit    = gprs_xmit; /* mandatory */
+        net->change_mtu         = gprs_set_mtu;
+        net->get_stats          = gprs_get_stats;
+}
+
+/*
+ * External interface
+ */
+
+/*
+ * Attach a GPRS interface to a datagram socket.
+ * Returns the interface index on success, negative error code on error.
+ */
+int gprs_attach(struct sock *sk)
+{
+        static const char ifname[] = "gprs%d";
+        struct gprs_dev *dev;
+        struct net_device *net;
+        int err;
+
+        if (unlikely(sk->sk_type == SOCK_STREAM))
+                return -EINVAL; /* need packet boundaries */
+
+        /* Create net device */
+        net = alloc_netdev(sizeof(*dev), ifname, gprs_setup);
+        if (!net)
+                return -ENOMEM;
+        dev = netdev_priv(net);
+        dev->net = net;
+        dev->tx_max = 0;
+        spin_lock_init(&dev->tx_lock);
+        skb_queue_head_init(&dev->tx_queue);
+        INIT_WORK(&dev->tx_work, gprs_tx);
+
+        netif_stop_queue(net);
+        err = register_netdev(net);
+        if (err) {
+                free_netdev(net);
+                return err;
+        }
+
+        lock_sock(sk);
+        if (unlikely(sk->sk_user_data)) {
+                err = -EBUSY;
+                goto out_rel;
+        }
+        if (unlikely((1 << sk->sk_state & (TCPF_CLOSE|TCPF_LISTEN)) ||
+                        sock_flag(sk, SOCK_DEAD))) {
+                err = -EINVAL;
+                goto out_rel;
+        }
+        sk->sk_user_data        = dev;
+        dev->old_state_change   = sk->sk_state_change;
+        dev->old_data_ready     = sk->sk_data_ready;
+        dev->old_write_space    = sk->sk_write_space;
+        sk->sk_state_change     = gprs_state_change;
+        sk->sk_data_ready       = gprs_data_ready;
+        sk->sk_write_space      = gprs_write_space;
+        release_sock(sk);
+
+        sock_hold(sk);
+        dev->sk = sk;
+
+        printk(KERN_DEBUG"%s: attached\n", net->name);
+        gprs_write_space(sk); /* kick off TX */
+        return net->ifindex;
+
+out_rel:
+        release_sock(sk);
+        unregister_netdev(net);
+        return err;
+}
+
+void gprs_detach(struct sock *sk)
+{
+        struct gprs_dev *dev = sk->sk_user_data;
+        struct net_device *net = dev->net;
+
+        lock_sock(sk);
+        sk->sk_user_data        = NULL;
+        sk->sk_state_change     = dev->old_state_change;
+        sk->sk_data_ready       = dev->old_data_ready;
+        sk->sk_write_space      = dev->old_write_space;
+        release_sock(sk);
+
+        printk(KERN_DEBUG"%s: detached\n", net->name);
+        unregister_netdev(net);
+        flush_scheduled_work();
+        sock_put(sk);
+        skb_queue_purge(&dev->tx_queue);
+}
diff --git a/net/phonet/pep.c b/net/phonet/pep.c
index d564d07cb797..bc6d50f83249 100644
--- a/net/phonet/pep.c
+++ b/net/phonet/pep.c
@@ -31,6 +31,7 @@
 #include <linux/phonet.h>
 #include <net/phonet/phonet.h>
 #include <net/phonet/pep.h>
+#include <net/phonet/gprs.h>
 
 /* sk_state values:
  * TCP_CLOSE            sock not in use yet
@@ -612,6 +613,7 @@ drop:
 static void pep_sock_close(struct sock *sk, long timeout)
 {
         struct pep_sock *pn = pep_sk(sk);
+        int ifindex = 0;
 
         sk_common_release(sk);
 
@@ -625,7 +627,12 @@ static void pep_sock_close(struct sock *sk, long timeout)
                         sk_del_node_init(sknode);
                 sk->sk_state = TCP_CLOSE;
         }
+        ifindex = pn->ifindex;
+        pn->ifindex = 0;
         release_sock(sk);
+
+        if (ifindex)
+                gprs_detach(sk);
 }
 
 static int pep_wait_connreq(struct sock *sk, int noblock)
@@ -730,12 +737,107 @@ static int pep_init(struct sock *sk)
         return 0;
 }
 
+static int pep_setsockopt(struct sock *sk, int level, int optname,
+                                char __user *optval, int optlen)
+{
+        struct pep_sock *pn = pep_sk(sk);
+        int val = 0, err = 0;
+
+        if (level != SOL_PNPIPE)
+                return -ENOPROTOOPT;
+        if (optlen >= sizeof(int)) {
+                if (get_user(val, (int __user *) optval))
+                        return -EFAULT;
+        }
+
+        lock_sock(sk);
+        switch (optname) {
+        case PNPIPE_ENCAP:
+                if (val && val != PNPIPE_ENCAP_IP) {
+                        err = -EINVAL;
+                        break;
+                }
+                if (!pn->ifindex == !val)
+                        break; /* Nothing to do! */
+                if (!capable(CAP_NET_ADMIN)) {
+                        err = -EPERM;
+                        break;
+                }
+                if (val) {
+                        release_sock(sk);
+                        err = gprs_attach(sk);
+                        if (err > 0) {
+                                pn->ifindex = err;
+                                err = 0;
+                        }
+                } else {
+                        pn->ifindex = 0;
+                        release_sock(sk);
+                        gprs_detach(sk);
+                        err = 0;
+                }
+                goto out_norel;
+        default:
+                err = -ENOPROTOOPT;
+        }
+        release_sock(sk);
+
+out_norel:
+        return err;
+}
+
+static int pep_getsockopt(struct sock *sk, int level, int optname,
+                                char __user *optval, int __user *optlen)
+{
+        struct pep_sock *pn = pep_sk(sk);
+        int len, val;
+
+        if (level != SOL_PNPIPE)
+                return -ENOPROTOOPT;
+        if (get_user(len, optlen))
+                return -EFAULT;
+
+        switch (optname) {
+        case PNPIPE_ENCAP:
+                val = pn->ifindex ? PNPIPE_ENCAP_IP : PNPIPE_ENCAP_NONE;
+                break;
+        case PNPIPE_IFINDEX:
+                val = pn->ifindex;
+                break;
+        default:
+                return -ENOPROTOOPT;
+        }
+
+        len = min_t(unsigned int, sizeof(int), len);
+        if (put_user(len, optlen))
+                return -EFAULT;
+        if (put_user(val, (int __user *) optval))
+                return -EFAULT;
+        return 0;
+}
+
+static int pipe_skb_send(struct sock *sk, struct sk_buff *skb)
+{
+        struct pep_sock *pn = pep_sk(sk);
+        struct pnpipehdr *ph;
+
+        skb_push(skb, 3);
+        skb_reset_transport_header(skb);
+        ph = pnp_hdr(skb);
+        ph->utid = 0;
+        ph->message_id = PNS_PIPE_DATA;
+        ph->pipe_handle = pn->pipe_handle;
+        if (pn_flow_safe(pn->tx_fc) && pn->tx_credits)
+                pn->tx_credits--;
+
+        return pn_skb_send(sk, skb, &pipe_srv);
+}
+
 static int pep_sendmsg(struct kiocb *iocb, struct sock *sk,
                         struct msghdr *msg, size_t len)
 {
         struct pep_sock *pn = pep_sk(sk);
         struct sk_buff *skb = NULL;
-        struct pnpipehdr *ph;
         long timeo;
         int flags = msg->msg_flags;
         int err, done;
@@ -801,16 +903,7 @@ disabled:
         if (err < 0)
                 goto out;
 
-        __skb_push(skb, 3);
-        skb_reset_transport_header(skb);
-        ph = pnp_hdr(skb);
-        ph->utid = 0;
-        ph->message_id = PNS_PIPE_DATA;
-        ph->pipe_handle = pn->pipe_handle;
-        if (pn_flow_safe(pn->tx_fc)) /* credit-based flow control */
-                pn->tx_credits--;
-
-        err = pn_skb_send(sk, skb, &pipe_srv);
+        err = pipe_skb_send(sk, skb);
         if (err >= 0)
                 err = len; /* success! */
         skb = NULL;
@@ -820,6 +913,50 @@ out:
         return err;
 }
 
+int pep_writeable(struct sock *sk)
+{
+        struct pep_sock *pn = pep_sk(sk);
+
+        return (sk->sk_state == TCP_ESTABLISHED) ? pn->tx_credits : 0;
+}
+
+int pep_write(struct sock *sk, struct sk_buff *skb)
+{
+        struct sk_buff *rskb, *fs;
+        int flen = 0;
+
+        rskb = alloc_skb(MAX_PNPIPE_HEADER, GFP_ATOMIC);
+        if (!rskb) {
+                kfree_skb(skb);
+                return -ENOMEM;
+        }
+        skb_shinfo(rskb)->frag_list = skb;
+        rskb->len += skb->len;
+        rskb->data_len += rskb->len;
+        rskb->truesize += rskb->len;
+
+        /* Avoid nested fragments */
+        for (fs = skb_shinfo(skb)->frag_list; fs; fs = fs->next)
+                flen += fs->len;
+        skb->next = skb_shinfo(skb)->frag_list;
+        skb_shinfo(skb)->frag_list = NULL;
+        skb->len -= flen;
+        skb->data_len -= flen;
+        skb->truesize -= flen;
+
+        skb_reserve(rskb, MAX_PHONET_HEADER + 3);
+        return pipe_skb_send(sk, rskb);
+}
+
+struct sk_buff *pep_read(struct sock *sk)
+{
+        struct sk_buff *skb = skb_dequeue(&sk->sk_receive_queue);
+
+        if (sk->sk_state == TCP_ESTABLISHED)
+                pipe_grant_credits(sk);
+        return skb;
+}
+
 static int pep_recvmsg(struct kiocb *iocb, struct sock *sk,
                         struct msghdr *msg, size_t len, int noblock,
                         int flags, int *addr_len)
@@ -902,6 +1039,8 @@ static struct proto pep_proto = {
         .accept         = pep_sock_accept,
         .ioctl          = pep_ioctl,
         .init           = pep_init,
+        .setsockopt     = pep_setsockopt,
+        .getsockopt     = pep_getsockopt,
         .sendmsg        = pep_sendmsg,
         .recvmsg        = pep_recvmsg,
         .backlog_rcv    = pep_do_rcv,
diff --git a/net/phonet/socket.c b/net/phonet/socket.c
index a9c3d1f2e9db..d81740187fb4 100644
--- a/net/phonet/socket.c
+++ b/net/phonet/socket.c
@@ -342,11 +342,11 @@ const struct proto_ops phonet_stream_ops = {
         .ioctl          = pn_socket_ioctl,
         .listen         = pn_socket_listen,
         .shutdown       = sock_no_shutdown,
-        .setsockopt     = sock_no_setsockopt,
-        .getsockopt     = sock_no_getsockopt,
+        .setsockopt     = sock_common_setsockopt,
+        .getsockopt     = sock_common_getsockopt,
 #ifdef CONFIG_COMPAT
-        .compat_setsockopt = sock_no_setsockopt,
-        .compat_getsockopt = compat_sock_no_getsockopt,
+        .compat_setsockopt = compat_sock_common_setsockopt,
+        .compat_getsockopt = compat_sock_common_getsockopt,
 #endif
         .sendmsg        = pn_socket_sendmsg,
         .recvmsg        = sock_common_recvmsg,