[DCCP]: Initial implementation

Development to this point was done on a subversion repository at:

http://oops.ghostprotocols.net:81/cgi-bin/viewcvs.cgi/dccp-2.6/

This repository will be kept at this site for the foreseable future,
so that interested parties can see the history of this code,
attributions, etc.

If I ever decide to take this offline I'll provide the full history at
some other suitable place.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 818 insertions, 0 deletions

diff --git a/net/dccp/proto.c b/net/dccp/proto.c
new file mode 100644
index 00000000000..70284e6afe0
--- /dev/null
+++ b/net/dccp/proto.c
@@ -0,0 +1,818 @@
+/*
+ *  net/dccp/proto.c
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *      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.
+ */
+
+#include <linux/config.h>
+#include <linux/dccp.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/in.h>
+#include <linux/if_arp.h>
+#include <linux/init.h>
+#include <linux/random.h>
+#include <net/checksum.h>
+
+#include <net/inet_common.h>
+#include <net/ip.h>
+#include <net/protocol.h>
+#include <net/sock.h>
+#include <net/xfrm.h>
+
+#include <asm/semaphore.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include <linux/delay.h>
+#include <linux/poll.h>
+#include <linux/dccp.h>
+
+#include "ccid.h"
+#include "dccp.h"
+
+DEFINE_SNMP_STAT(struct dccp_mib, dccp_statistics);
+
+atomic_t dccp_orphan_count = ATOMIC_INIT(0);
+
+static struct net_protocol dccp_protocol = {
+        .handler        = dccp_v4_rcv,
+        .err_handler    = dccp_v4_err,
+};
+
+const char *dccp_packet_name(const int type)
+{
+        static const char *dccp_packet_names[] = {
+                [DCCP_PKT_REQUEST]  = "REQUEST",
+                [DCCP_PKT_RESPONSE] = "RESPONSE",
+                [DCCP_PKT_DATA]     = "DATA",
+                [DCCP_PKT_ACK]      = "ACK",
+                [DCCP_PKT_DATAACK]  = "DATAACK",
+                [DCCP_PKT_CLOSEREQ] = "CLOSEREQ",
+                [DCCP_PKT_CLOSE]    = "CLOSE",
+                [DCCP_PKT_RESET]    = "RESET",
+                [DCCP_PKT_SYNC]     = "SYNC",
+                [DCCP_PKT_SYNCACK]  = "SYNCACK",
+        };
+
+        if (type >= DCCP_NR_PKT_TYPES)
+                return "INVALID";
+        else
+                return dccp_packet_names[type];
+}
+
+EXPORT_SYMBOL_GPL(dccp_packet_name);
+
+const char *dccp_state_name(const int state)
+{
+        static char *dccp_state_names[] = {
+        [DCCP_OPEN]       = "OPEN",
+        [DCCP_REQUESTING] = "REQUESTING",
+        [DCCP_PARTOPEN]   = "PARTOPEN",
+        [DCCP_LISTEN]     = "LISTEN",
+        [DCCP_RESPOND]    = "RESPOND",
+        [DCCP_CLOSING]    = "CLOSING",
+        [DCCP_TIME_WAIT]  = "TIME_WAIT",
+        [DCCP_CLOSED]     = "CLOSED",
+        };
+
+        if (state >= DCCP_MAX_STATES)
+                return "INVALID STATE!";
+        else
+                return dccp_state_names[state];
+}
+
+EXPORT_SYMBOL_GPL(dccp_state_name);
+
+static inline int dccp_listen_start(struct sock *sk)
+{
+        dccp_sk(sk)->dccps_role = DCCP_ROLE_LISTEN;
+        return inet_csk_listen_start(sk, TCP_SYNQ_HSIZE);
+}
+
+int dccp_disconnect(struct sock *sk, int flags)
+{
+        struct inet_connection_sock *icsk = inet_csk(sk);
+        struct inet_sock *inet = inet_sk(sk);
+        int err = 0;
+        const int old_state = sk->sk_state;
+
+        if (old_state != DCCP_CLOSED)
+                dccp_set_state(sk, DCCP_CLOSED);
+
+        /* ABORT function of RFC793 */
+        if (old_state == DCCP_LISTEN) {
+                inet_csk_listen_stop(sk);
+        /* FIXME: do the active reset thing */
+        } else if (old_state == DCCP_REQUESTING)
+                sk->sk_err = ECONNRESET;
+
+        dccp_clear_xmit_timers(sk);
+        __skb_queue_purge(&sk->sk_receive_queue);
+        if (sk->sk_send_head != NULL) {
+                __kfree_skb(sk->sk_send_head);
+                sk->sk_send_head = NULL;
+        }
+
+        inet->dport = 0;
+
+        if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
+                inet_reset_saddr(sk);
+
+        sk->sk_shutdown = 0;
+        sock_reset_flag(sk, SOCK_DONE);
+
+        icsk->icsk_backoff = 0;
+        inet_csk_delack_init(sk);
+        __sk_dst_reset(sk);
+
+        BUG_TRAP(!inet->num || icsk->icsk_bind_hash);
+
+        sk->sk_error_report(sk);
+        return err;
+}
+
+int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg)
+{
+        dccp_pr_debug("entry\n");
+        return -ENOIOCTLCMD;
+}
+
+int dccp_setsockopt(struct sock *sk, int level, int optname,
+                    char *optval, int optlen)
+{
+        dccp_pr_debug("entry\n");
+
+        if (level != SOL_DCCP)
+                return ip_setsockopt(sk, level, optname, optval, optlen);
+
+        return -EOPNOTSUPP;
+}
+
+int dccp_getsockopt(struct sock *sk, int level, int optname,
+                    char *optval, int *optlen)
+{
+        dccp_pr_debug("entry\n");
+
+        if (level != SOL_DCCP)
+                return ip_getsockopt(sk, level, optname, optval, optlen);
+
+        return -EOPNOTSUPP;
+}
+
+int dccp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
+                 size_t len)
+{
+        const struct dccp_sock *dp = dccp_sk(sk);
+        const int flags = msg->msg_flags;
+        const int noblock = flags & MSG_DONTWAIT;
+        struct sk_buff *skb;
+        int rc, size;
+        long timeo;
+
+        if (len > dp->dccps_mss_cache)
+                return -EMSGSIZE;
+
+        lock_sock(sk);
+
+        timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
+
+        /*
+         * We have to use sk_stream_wait_connect here to set sk_write_pending,
+         * so that the trick in dccp_rcv_request_sent_state_process.
+         */
+        /* Wait for a connection to finish. */
+        if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN | DCCPF_CLOSING))
+                if ((rc = sk_stream_wait_connect(sk, &timeo)) != 0)
+                        goto out_err;
+
+        size = sk->sk_prot->max_header + len;
+        release_sock(sk);
+        skb = sock_alloc_send_skb(sk, size, noblock, &rc);
+        lock_sock(sk);
+
+        if (skb == NULL)
+                goto out_release;
+
+        skb_reserve(skb, sk->sk_prot->max_header);
+        rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
+        if (rc == 0) {
+                struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
+                const struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
+                long delay; 
+
+                /*
+                 * XXX: This is just to match the Waikato tree CA interaction
+                 * points, after the CCID3 code is stable and I have a better
+                 * understanding of behaviour I'll change this to look more like
+                 * TCP.
+                 */
+                while (1) {
+                        rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk,
+                                                    skb, len, &delay);
+                        if (rc == 0)
+                                break;
+                        if (rc != -EAGAIN)
+                                goto out_discard;
+                        if (delay > timeo)
+                                goto out_discard;
+                        release_sock(sk);
+                        delay = schedule_timeout(delay);
+                        lock_sock(sk);
+                        timeo -= delay;
+                        if (signal_pending(current))
+                                goto out_interrupted;
+                        rc = -EPIPE;
+                        if (!(sk->sk_state == DCCP_PARTOPEN || sk->sk_state == DCCP_OPEN))
+                                goto out_discard;
+                }
+
+                if (sk->sk_state == DCCP_PARTOPEN) {
+                        /* See 8.1.5.  Handshake Completion */
+                        inet_csk_schedule_ack(sk);
+                        inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, inet_csk(sk)->icsk_rto, TCP_RTO_MAX);
+                        dcb->dccpd_type = DCCP_PKT_DATAACK;
+                        /* FIXME: we really should have a dccps_ack_pending or use icsk */
+                } else if (inet_csk_ack_scheduled(sk) ||
+                           (dp->dccps_options.dccpo_send_ack_vector &&
+                            ap->dccpap_buf_ackno != DCCP_MAX_SEQNO + 1 &&
+                            ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1))
+                        dcb->dccpd_type = DCCP_PKT_DATAACK;
+                else
+                        dcb->dccpd_type = DCCP_PKT_DATA;
+                dccp_transmit_skb(sk, skb);
+                ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
+        } else {
+out_discard:
+                kfree_skb(skb);
+        }
+out_release:
+        release_sock(sk);
+        return rc ? : len;
+out_err:
+        rc = sk_stream_error(sk, flags, rc);
+        goto out_release;
+out_interrupted:
+        rc = sock_intr_errno(timeo);
+        goto out_discard;
+}
+
+EXPORT_SYMBOL(dccp_sendmsg);
+
+int dccp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
+                 size_t len, int nonblock, int flags, int *addr_len)
+{
+        const struct dccp_hdr *dh;
+        int copied = 0;
+        unsigned long used;
+        int err;
+        int target;             /* Read at least this many bytes */
+        long timeo;
+
+        lock_sock(sk);
+
+        err = -ENOTCONN;
+        if (sk->sk_state == DCCP_LISTEN)
+                goto out;
+
+        timeo = sock_rcvtimeo(sk, nonblock);
+
+        /* Urgent data needs to be handled specially. */
+        if (flags & MSG_OOB)
+                goto recv_urg;
+
+        /* FIXME */
+#if 0
+        seq = &tp->copied_seq;
+        if (flags & MSG_PEEK) {
+                peek_seq = tp->copied_seq;
+                seq = &peek_seq;
+        }
+#endif
+
+        target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
+
+        do {
+                struct sk_buff *skb;
+                u32 offset;
+
+        /* FIXME */
+#if 0
+                /* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
+                if (tp->urg_data && tp->urg_seq == *seq) {
+                        if (copied)
+                                break;
+                        if (signal_pending(current)) {
+                                copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
+                                break;
+                        }
+                }
+#endif
+
+                /* Next get a buffer. */
+
+                skb = skb_peek(&sk->sk_receive_queue);
+                do {
+                        if (!skb)
+                                break;
+
+                        offset = 0;
+                        dh = dccp_hdr(skb);
+
+                        if (dh->dccph_type == DCCP_PKT_DATA ||
+                            dh->dccph_type == DCCP_PKT_DATAACK)
+                                goto found_ok_skb;
+
+                        if (dh->dccph_type == DCCP_PKT_RESET ||
+                            dh->dccph_type == DCCP_PKT_CLOSE) {
+                                dccp_pr_debug("found fin ok!\n");
+                                goto found_fin_ok;
+                        }
+                        dccp_pr_debug("packet_type=%s\n", dccp_packet_name(dh->dccph_type));
+                        BUG_TRAP(flags & MSG_PEEK);
+                        skb = skb->next;
+                } while (skb != (struct sk_buff *)&sk->sk_receive_queue);
+
+                /* Well, if we have backlog, try to process it now yet. */
+                if (copied >= target && !sk->sk_backlog.tail)
+                        break;
+
+                if (copied) {
+                        if (sk->sk_err ||
+                            sk->sk_state == DCCP_CLOSED ||
+                            (sk->sk_shutdown & RCV_SHUTDOWN) ||
+                            !timeo ||
+                            signal_pending(current) ||
+                            (flags & MSG_PEEK))
+                                break;
+                } else {
+                        if (sock_flag(sk, SOCK_DONE))
+                                break;
+
+                        if (sk->sk_err) {
+                                copied = sock_error(sk);
+                                break;
+                        }
+
+                        if (sk->sk_shutdown & RCV_SHUTDOWN)
+                                break;
+
+                        if (sk->sk_state == DCCP_CLOSED) {
+                                if (!sock_flag(sk, SOCK_DONE)) {
+                                        /* This occurs when user tries to read
+                                         * from never connected socket.
+                                         */
+                                        copied = -ENOTCONN;
+                                        break;
+                                }
+                                break;
+                        }
+
+                        if (!timeo) {
+                                copied = -EAGAIN;
+                                break;
+                        }
+
+                        if (signal_pending(current)) {
+                                copied = sock_intr_errno(timeo);
+                                break;
+                        }
+                }
+
+                /* FIXME: cleanup_rbuf(sk, copied); */
+
+                if (copied >= target) {
+                        /* Do not sleep, just process backlog. */
+                        release_sock(sk);
+                        lock_sock(sk);
+                } else
+                        sk_wait_data(sk, &timeo);
+
+                continue;
+
+        found_ok_skb:
+                /* Ok so how much can we use? */
+                used = skb->len - offset;
+                if (len < used)
+                        used = len;
+
+                if (!(flags & MSG_TRUNC)) {
+                        err = skb_copy_datagram_iovec(skb, offset,
+                                                      msg->msg_iov, used);
+                        if (err) {
+                                /* Exception. Bailout! */
+                                if (!copied)
+                                        copied = -EFAULT;
+                                break;
+                        }
+                }
+
+                copied += used;
+                len -= used;
+
+                /* FIXME: tcp_rcv_space_adjust(sk); */
+
+//skip_copy:
+                if (used + offset < skb->len)
+                        continue;
+
+                if (!(flags & MSG_PEEK))
+                        sk_eat_skb(sk, skb);
+                continue;
+        found_fin_ok:
+                if (!(flags & MSG_PEEK))
+                        sk_eat_skb(sk, skb);
+                break;
+                
+        } while (len > 0);
+
+        /* According to UNIX98, msg_name/msg_namelen are ignored
+         * on connected socket. I was just happy when found this 8) --ANK
+         */
+
+        /* Clean up data we have read: This will do ACK frames. */
+        /* FIXME: cleanup_rbuf(sk, copied); */
+
+        release_sock(sk);
+        return copied;
+
+out:
+        release_sock(sk);
+        return err;
+
+recv_urg:
+        /* FIXME: err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len); */
+        goto out;
+}
+
+static int inet_dccp_listen(struct socket *sock, int backlog)
+{
+        struct sock *sk = sock->sk;
+        unsigned char old_state;
+        int err;
+
+        lock_sock(sk);
+
+        err = -EINVAL;
+        if (sock->state != SS_UNCONNECTED || sock->type != SOCK_DCCP)
+                goto out;
+
+        old_state = sk->sk_state;
+        if (!((1 << old_state) & (DCCPF_CLOSED | DCCPF_LISTEN)))
+                goto out;
+
+        /* Really, if the socket is already in listen state
+         * we can only allow the backlog to be adjusted.
+         */
+        if (old_state != DCCP_LISTEN) {
+                /*
+                 * FIXME: here it probably should be sk->sk_prot->listen_start
+                 * see tcp_listen_start
+                 */
+                err = dccp_listen_start(sk);
+                if (err)
+                        goto out;
+        }
+        sk->sk_max_ack_backlog = backlog;
+        err = 0;
+
+out:
+        release_sock(sk);
+        return err;
+}
+
+static const unsigned char dccp_new_state[] = {
+        /* current state:        new state:      action:        */
+        [0]                     = DCCP_CLOSED,
+        [DCCP_OPEN]             = DCCP_CLOSING | DCCP_ACTION_FIN,
+        [DCCP_REQUESTING]       = DCCP_CLOSED,
+        [DCCP_PARTOPEN] = DCCP_CLOSING | DCCP_ACTION_FIN,
+        [DCCP_LISTEN]           = DCCP_CLOSED,
+        [DCCP_RESPOND]  = DCCP_CLOSED,
+        [DCCP_CLOSING]  = DCCP_CLOSED,
+        [DCCP_TIME_WAIT]        = DCCP_CLOSED,
+        [DCCP_CLOSED]   = DCCP_CLOSED,
+};
+
+static int dccp_close_state(struct sock *sk)
+{
+        const int next = dccp_new_state[sk->sk_state];
+        const int ns = next & DCCP_STATE_MASK;
+
+        if (ns != sk->sk_state)
+                dccp_set_state(sk, ns);
+
+        return next & DCCP_ACTION_FIN;
+}
+
+void dccp_close(struct sock *sk, long timeout)
+{
+        struct sk_buff *skb;
+
+        lock_sock(sk);
+
+        sk->sk_shutdown = SHUTDOWN_MASK;
+
+        if (sk->sk_state == DCCP_LISTEN) {
+                dccp_set_state(sk, DCCP_CLOSED);
+
+                /* Special case. */
+                inet_csk_listen_stop(sk);
+
+                goto adjudge_to_death;
+        }
+
+        /*
+         * We need to flush the recv. buffs.  We do this only on the
+         * descriptor close, not protocol-sourced closes, because the
+          *reader process may not have drained the data yet!
+         */
+        /* FIXME: check for unread data */
+        while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
+                __kfree_skb(skb);
+        }
+
+        if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
+                /* Check zero linger _after_ checking for unread data. */
+                sk->sk_prot->disconnect(sk, 0);
+        } else if (dccp_close_state(sk)) {
+                dccp_send_close(sk);
+        }
+
+        sk_stream_wait_close(sk, timeout);
+
+adjudge_to_death:
+        release_sock(sk);
+        /*
+         * Now socket is owned by kernel and we acquire BH lock
+         * to finish close. No need to check for user refs.
+         */
+        local_bh_disable();
+        bh_lock_sock(sk);
+        BUG_TRAP(!sock_owned_by_user(sk));
+
+        sock_hold(sk);
+        sock_orphan(sk);
+                                                
+        if (sk->sk_state != DCCP_CLOSED)
+                dccp_set_state(sk, DCCP_CLOSED);
+
+        atomic_inc(&dccp_orphan_count);
+        if (sk->sk_state == DCCP_CLOSED)
+                inet_csk_destroy_sock(sk);
+
+        /* Otherwise, socket is reprieved until protocol close. */
+
+        bh_unlock_sock(sk);
+        local_bh_enable();
+        sock_put(sk);
+}
+
+void dccp_shutdown(struct sock *sk, int how)
+{
+        dccp_pr_debug("entry\n");
+}
+
+struct proto_ops inet_dccp_ops = {
+        .family         = PF_INET,
+        .owner          = THIS_MODULE,
+        .release        = inet_release,
+        .bind           = inet_bind,
+        .connect        = inet_stream_connect,
+        .socketpair     = sock_no_socketpair,
+        .accept         = inet_accept,
+        .getname        = inet_getname,
+        .poll           = sock_no_poll,
+        .ioctl          = inet_ioctl,
+        .listen         = inet_dccp_listen, /* FIXME: work on inet_listen to rename it to sock_common_listen */
+        .shutdown       = inet_shutdown,
+        .setsockopt     = sock_common_setsockopt,
+        .getsockopt     = sock_common_getsockopt,
+        .sendmsg        = inet_sendmsg,
+        .recvmsg        = sock_common_recvmsg,
+        .mmap           = sock_no_mmap,
+        .sendpage       = sock_no_sendpage,
+};
+
+extern struct net_proto_family inet_family_ops;
+
+static struct inet_protosw dccp_v4_protosw = {
+        .type           = SOCK_DCCP,
+        .protocol       = IPPROTO_DCCP,
+        .prot           = &dccp_v4_prot,
+        .ops            = &inet_dccp_ops,
+        .capability     = -1,
+        .no_check       = 0,
+        .flags          = 0,
+};
+
+/*
+ * This is the global socket data structure used for responding to
+ * the Out-of-the-blue (OOTB) packets. A control sock will be created
+ * for this socket at the initialization time.
+ */
+struct socket *dccp_ctl_socket;
+
+static char dccp_ctl_socket_err_msg[] __initdata =
+        KERN_ERR "DCCP: Failed to create the control socket.\n";
+
+static int __init dccp_ctl_sock_init(void)
+{
+        int rc = sock_create_kern(PF_INET, SOCK_DCCP, IPPROTO_DCCP,
+                                  &dccp_ctl_socket);
+        if (rc < 0)
+                printk(dccp_ctl_socket_err_msg);
+        else {
+                dccp_ctl_socket->sk->sk_allocation = GFP_ATOMIC;
+                inet_sk(dccp_ctl_socket->sk)->uc_ttl = -1;
+
+                /* Unhash it so that IP input processing does not even
+                 * see it, we do not wish this socket to see incoming
+                 * packets.
+                 */
+                dccp_ctl_socket->sk->sk_prot->unhash(dccp_ctl_socket->sk);
+        }
+
+        return rc;
+}
+
+static void __exit dccp_ctl_sock_exit(void)
+{
+        if (dccp_ctl_socket != NULL)
+                sock_release(dccp_ctl_socket);
+}
+
+static int __init init_dccp_v4_mibs(void)
+{
+        int rc = -ENOMEM;
+
+        dccp_statistics[0] = alloc_percpu(struct dccp_mib);
+        if (dccp_statistics[0] == NULL)
+                goto out;
+
+        dccp_statistics[1] = alloc_percpu(struct dccp_mib);
+        if (dccp_statistics[1] == NULL)
+                goto out_free_one;
+
+        rc = 0;
+out:
+        return rc;
+out_free_one:
+        free_percpu(dccp_statistics[0]);
+        dccp_statistics[0] = NULL;
+        goto out;
+
+}
+
+static int thash_entries;
+module_param(thash_entries, int, 0444);
+MODULE_PARM_DESC(thash_entries, "Number of ehash buckets");
+
+int dccp_debug;
+module_param(dccp_debug, int, 0444);
+MODULE_PARM_DESC(dccp_debug, "Enable debug messages");
+
+static int __init dccp_init(void)
+{
+        unsigned long goal;
+        int ehash_order, bhash_order, i;
+        int rc = proto_register(&dccp_v4_prot, 1);
+
+        if (rc)
+                goto out;
+
+        dccp_hashinfo.bind_bucket_cachep = kmem_cache_create("dccp_bind_bucket",
+                                               sizeof(struct inet_bind_bucket),
+                                               0, SLAB_HWCACHE_ALIGN,
+                                               NULL, NULL);
+        if (!dccp_hashinfo.bind_bucket_cachep)
+                goto out_proto_unregister;
+
+        /*
+         * Size and allocate the main established and bind bucket
+         * hash tables.
+         *
+         * The methodology is similar to that of the buffer cache.
+         */
+        if (num_physpages >= (128 * 1024))
+                goal = num_physpages >> (21 - PAGE_SHIFT);
+        else
+                goal = num_physpages >> (23 - PAGE_SHIFT);
+
+        if (thash_entries)
+                goal = (thash_entries * sizeof(struct inet_ehash_bucket)) >> PAGE_SHIFT;
+        for (ehash_order = 0; (1UL << ehash_order) < goal; ehash_order++)
+                ;
+        do {
+                dccp_hashinfo.ehash_size = (1UL << ehash_order) * PAGE_SIZE /
+                                        sizeof(struct inet_ehash_bucket);
+                dccp_hashinfo.ehash_size >>= 1;
+                while (dccp_hashinfo.ehash_size & (dccp_hashinfo.ehash_size - 1))
+                        dccp_hashinfo.ehash_size--;
+                dccp_hashinfo.ehash = (struct inet_ehash_bucket *)
+                        __get_free_pages(GFP_ATOMIC, ehash_order);
+        } while (!dccp_hashinfo.ehash && --ehash_order > 0);
+
+        if (!dccp_hashinfo.ehash) {
+                printk(KERN_CRIT "Failed to allocate DCCP "
+                                 "established hash table\n");
+                goto out_free_bind_bucket_cachep;
+        }
+
+        for (i = 0; i < (dccp_hashinfo.ehash_size << 1); i++) {
+                rwlock_init(&dccp_hashinfo.ehash[i].lock);
+                INIT_HLIST_HEAD(&dccp_hashinfo.ehash[i].chain);
+        }
+
+        bhash_order = ehash_order;
+
+        do {
+                dccp_hashinfo.bhash_size = (1UL << bhash_order) * PAGE_SIZE /
+                                        sizeof(struct inet_bind_hashbucket);
+                if ((dccp_hashinfo.bhash_size > (64 * 1024)) && bhash_order > 0)
+                        continue;
+                dccp_hashinfo.bhash = (struct inet_bind_hashbucket *)
+                        __get_free_pages(GFP_ATOMIC, bhash_order);
+        } while (!dccp_hashinfo.bhash && --bhash_order >= 0);
+
+        if (!dccp_hashinfo.bhash) {
+                printk(KERN_CRIT "Failed to allocate DCCP bind hash table\n");
+                goto out_free_dccp_ehash;
+        }
+
+        for (i = 0; i < dccp_hashinfo.bhash_size; i++) {
+                spin_lock_init(&dccp_hashinfo.bhash[i].lock);
+                INIT_HLIST_HEAD(&dccp_hashinfo.bhash[i].chain);
+        }
+
+        if (init_dccp_v4_mibs())
+                goto out_free_dccp_bhash;
+
+        rc = -EAGAIN;
+        if (inet_add_protocol(&dccp_protocol, IPPROTO_DCCP))
+                goto out_free_dccp_v4_mibs;
+
+        inet_register_protosw(&dccp_v4_protosw);
+
+        rc = dccp_ctl_sock_init();
+        if (rc)
+                goto out_unregister_protosw;
+out:
+        return rc;
+out_unregister_protosw:
+        inet_unregister_protosw(&dccp_v4_protosw);
+        inet_del_protocol(&dccp_protocol, IPPROTO_DCCP);
+out_free_dccp_v4_mibs:
+        free_percpu(dccp_statistics[0]);
+        free_percpu(dccp_statistics[1]);
+        dccp_statistics[0] = dccp_statistics[1] = NULL;
+out_free_dccp_bhash:
+        free_pages((unsigned long)dccp_hashinfo.bhash, bhash_order);
+        dccp_hashinfo.bhash = NULL;
+out_free_dccp_ehash:
+        free_pages((unsigned long)dccp_hashinfo.ehash, ehash_order);
+        dccp_hashinfo.ehash = NULL;
+out_free_bind_bucket_cachep:
+        kmem_cache_destroy(dccp_hashinfo.bind_bucket_cachep);
+        dccp_hashinfo.bind_bucket_cachep = NULL;
+out_proto_unregister:
+        proto_unregister(&dccp_v4_prot);
+        goto out;
+}
+
+static const char dccp_del_proto_err_msg[] __exitdata =
+        KERN_ERR "can't remove dccp net_protocol\n";
+
+static void __exit dccp_fini(void)
+{
+        dccp_ctl_sock_exit();
+
+        inet_unregister_protosw(&dccp_v4_protosw);
+
+        if (inet_del_protocol(&dccp_protocol, IPPROTO_DCCP) < 0)
+                printk(dccp_del_proto_err_msg);
+
+        /* Free the control endpoint.  */
+        sock_release(dccp_ctl_socket);
+
+        proto_unregister(&dccp_v4_prot);
+
+        kmem_cache_destroy(dccp_hashinfo.bind_bucket_cachep);
+}
+
+module_init(dccp_init);
+module_exit(dccp_fini);
+
+/* __stringify doesn't likes enums, so use SOCK_DCCP (6) value directly  */
+MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-6");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@conectiva.com.br>");
+MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");