sctp: Add Auto-ASCONF support (core).

SCTP reconfigure the IP addresses in the association by using
ASCONF chunks as mentioned in RFC5061.  For example, we can
start to use the newly configured IP address in the existing
association.  This patch implements automatic ASCONF operation
in the SCTP stack with address events in the host computer,
which is called auto_asconf.

Signed-off-by: Michio Honda <micchie@sfc.wide.ad.jp>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Acked-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 147 insertions, 0 deletions

diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 67380a29e2e9..013c6136c546 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -623,6 +623,142 @@ static void sctp_v4_ecn_capable(struct sock *sk)
         INET_ECN_xmit(sk);
 }
 
+void sctp_addr_wq_timeout_handler(unsigned long arg)
+{
+        struct sctp_sockaddr_entry *addrw, *temp;
+        struct sctp_sock *sp;
+
+        spin_lock_bh(&sctp_addr_wq_lock);
+
+        list_for_each_entry_safe(addrw, temp, &sctp_addr_waitq, list) {
+                SCTP_DEBUG_PRINTK_IPADDR("sctp_addrwq_timo_handler: the first ent in wq %p is ",
+                    " for cmd %d at entry %p\n", &sctp_addr_waitq, &addrw->a, addrw->state,
+                    addrw);
+
+                /* Now we send an ASCONF for each association */
+                /* Note. we currently don't handle link local IPv6 addressees */
+                if (addrw->a.sa.sa_family == AF_INET6) {
+                        struct in6_addr *in6;
+
+                        if (ipv6_addr_type(&addrw->a.v6.sin6_addr) &
+                            IPV6_ADDR_LINKLOCAL)
+                                goto free_next;
+
+                        in6 = (struct in6_addr *)&addrw->a.v6.sin6_addr;
+                        if (ipv6_chk_addr(&init_net, in6, NULL, 0) == 0 &&
+                            addrw->state == SCTP_ADDR_NEW) {
+                                unsigned long timeo_val;
+
+                                SCTP_DEBUG_PRINTK("sctp_timo_handler: this is on DAD, trying %d sec later\n",
+                                    SCTP_ADDRESS_TICK_DELAY);
+                                timeo_val = jiffies;
+                                timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
+                                mod_timer(&sctp_addr_wq_timer, timeo_val);
+                                break;
+                        }
+                }
+
+                list_for_each_entry(sp, &sctp_auto_asconf_splist, auto_asconf_list) {
+                        struct sock *sk;
+
+                        sk = sctp_opt2sk(sp);
+                        /* ignore bound-specific endpoints */
+                        if (!sctp_is_ep_boundall(sk))
+                                continue;
+                        sctp_bh_lock_sock(sk);
+                        if (sctp_asconf_mgmt(sp, addrw) < 0)
+                                SCTP_DEBUG_PRINTK("sctp_addrwq_timo_handler: sctp_asconf_mgmt failed\n");
+                        sctp_bh_unlock_sock(sk);
+                }
+free_next:
+                list_del(&addrw->list);
+                kfree(addrw);
+        }
+        spin_unlock_bh(&sctp_addr_wq_lock);
+}
+
+static void sctp_free_addr_wq(void)
+{
+        struct sctp_sockaddr_entry *addrw;
+        struct sctp_sockaddr_entry *temp;
+
+        spin_lock_bh(&sctp_addr_wq_lock);
+        del_timer(&sctp_addr_wq_timer);
+        list_for_each_entry_safe(addrw, temp, &sctp_addr_waitq, list) {
+                list_del(&addrw->list);
+                kfree(addrw);
+        }
+        spin_unlock_bh(&sctp_addr_wq_lock);
+}
+
+/* lookup the entry for the same address in the addr_waitq
+ * sctp_addr_wq MUST be locked
+ */
+static struct sctp_sockaddr_entry *sctp_addr_wq_lookup(struct sctp_sockaddr_entry *addr)
+{
+        struct sctp_sockaddr_entry *addrw;
+
+        list_for_each_entry(addrw, &sctp_addr_waitq, list) {
+                if (addrw->a.sa.sa_family != addr->a.sa.sa_family)
+                        continue;
+                if (addrw->a.sa.sa_family == AF_INET) {
+                        if (addrw->a.v4.sin_addr.s_addr ==
+                            addr->a.v4.sin_addr.s_addr)
+                                return addrw;
+                } else if (addrw->a.sa.sa_family == AF_INET6) {
+                        if (ipv6_addr_equal(&addrw->a.v6.sin6_addr,
+                            &addr->a.v6.sin6_addr))
+                                return addrw;
+                }
+        }
+        return NULL;
+}
+
+void sctp_addr_wq_mgmt(struct sctp_sockaddr_entry *addr, int cmd)
+{
+        struct sctp_sockaddr_entry *addrw;
+        unsigned long timeo_val;
+
+        /* first, we check if an opposite message already exist in the queue.
+         * If we found such message, it is removed.
+         * This operation is a bit stupid, but the DHCP client attaches the
+         * new address after a couple of addition and deletion of that address
+         */
+
+        spin_lock_bh(&sctp_addr_wq_lock);
+        /* Offsets existing events in addr_wq */
+        addrw = sctp_addr_wq_lookup(addr);
+        if (addrw) {
+                if (addrw->state != cmd) {
+                        SCTP_DEBUG_PRINTK_IPADDR("sctp_addr_wq_mgmt offsets existing entry for %d ",
+                            " in wq %p\n", addrw->state, &addrw->a,
+                            &sctp_addr_waitq);
+                        list_del(&addrw->list);
+                        kfree(addrw);
+                }
+                spin_unlock_bh(&sctp_addr_wq_lock);
+                return;
+        }
+
+        /* OK, we have to add the new address to the wait queue */
+        addrw = kmemdup(addr, sizeof(struct sctp_sockaddr_entry), GFP_ATOMIC);
+        if (addrw == NULL) {
+                spin_unlock_bh(&sctp_addr_wq_lock);
+                return;
+        }
+        addrw->state = cmd;
+        list_add_tail(&addrw->list, &sctp_addr_waitq);
+        SCTP_DEBUG_PRINTK_IPADDR("sctp_addr_wq_mgmt add new entry for cmd:%d ",
+            " in wq %p\n", addrw->state, &addrw->a, &sctp_addr_waitq);
+
+        if (!timer_pending(&sctp_addr_wq_timer)) {
+                timeo_val = jiffies;
+                timeo_val += msecs_to_jiffies(SCTP_ADDRESS_TICK_DELAY);
+                mod_timer(&sctp_addr_wq_timer, timeo_val);
+        }
+        spin_unlock_bh(&sctp_addr_wq_lock);
+}
+
 /* Event handler for inet address addition/deletion events.
  * The sctp_local_addr_list needs to be protocted by a spin lock since
  * multiple notifiers (say IPv4 and IPv6) may be running at the same
@@ -650,6 +786,7 @@ static int sctp_inetaddr_event(struct notifier_block *this, unsigned long ev,
                         addr->valid = 1;
                         spin_lock_bh(&sctp_local_addr_lock);
                         list_add_tail_rcu(&addr->list, &sctp_local_addr_list);
+                        sctp_addr_wq_mgmt(addr, SCTP_ADDR_NEW);
                         spin_unlock_bh(&sctp_local_addr_lock);
                 }
                 break;
@@ -660,6 +797,7 @@ static int sctp_inetaddr_event(struct notifier_block *this, unsigned long ev,
                         if (addr->a.sa.sa_family == AF_INET &&
                                         addr->a.v4.sin_addr.s_addr ==
                                         ifa->ifa_local) {
+                                sctp_addr_wq_mgmt(addr, SCTP_ADDR_DEL);
                                 found = 1;
                                 addr->valid = 0;
                                 list_del_rcu(&addr->list);
@@ -1242,6 +1380,7 @@ SCTP_STATIC __init int sctp_init(void)
         /* Disable ADDIP by default. */
         sctp_addip_enable = 0;
         sctp_addip_noauth = 0;
+        sctp_default_auto_asconf = 0;
 
         /* Enable PR-SCTP by default. */
         sctp_prsctp_enable = 1;
@@ -1266,6 +1405,13 @@ SCTP_STATIC __init int sctp_init(void)
         spin_lock_init(&sctp_local_addr_lock);
         sctp_get_local_addr_list();
 
+        /* Initialize the address event list */
+        INIT_LIST_HEAD(&sctp_addr_waitq);
+        INIT_LIST_HEAD(&sctp_auto_asconf_splist);
+        spin_lock_init(&sctp_addr_wq_lock);
+        sctp_addr_wq_timer.expires = 0;
+        setup_timer(&sctp_addr_wq_timer, sctp_addr_wq_timeout_handler, 0);
+
         status = sctp_v4_protosw_init();
 
         if (status)
@@ -1337,6 +1483,7 @@ SCTP_STATIC __exit void sctp_exit(void)
         /* Unregister with inet6/inet layers. */
         sctp_v6_del_protocol();
         sctp_v4_del_protocol();
+        sctp_free_addr_wq();
 
         /* Free the control endpoint.  */
         inet_ctl_sock_destroy(sctp_ctl_sock);