tipc: send out RESET immediately when link goes down

[cascardo/linux.git] / net / tipc / link.c

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 8e23ab5..737b598 100644 (file)
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -125,6 +125,11 @@ bool tipc_link_is_reset(struct tipc_link *l)
        return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
 }
 
+bool tipc_link_is_establishing(struct tipc_link *l)
+{
+       return l->state == LINK_ESTABLISHING;
+}
+
 bool tipc_link_is_synching(struct tipc_link *l)
 {
        return l->state == LINK_SYNCHING;
@@ -321,14 +326,15 @@ int tipc_link_fsm_evt(struct tipc_link *l, int evt)
                switch (evt) {
                case LINK_ESTABLISH_EVT:
                        l->state = LINK_ESTABLISHED;
-                       rc |= TIPC_LINK_UP_EVT;
                        break;
                case LINK_FAILOVER_BEGIN_EVT:
                        l->state = LINK_FAILINGOVER;
                        break;
-               case LINK_PEER_RESET_EVT:
                case LINK_RESET_EVT:
+                       l->state = LINK_RESET;
+                       break;
                case LINK_FAILURE_EVT:
+               case LINK_PEER_RESET_EVT:
                case LINK_SYNCH_BEGIN_EVT:
                case LINK_FAILOVER_END_EVT:
                        break;
@@ -1056,6 +1062,18 @@ void tipc_link_build_ack_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
        tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, 0, xmitq);
 }
 
+/* tipc_link_build_reset_msg: prepare link RESET or ACTIVATE message
+ */
+void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq)
+{
+       int mtyp = RESET_MSG;
+
+       if (l->state == LINK_ESTABLISHING)
+               mtyp = ACTIVATE_MSG;
+
+       tipc_link_build_proto_msg(l, mtyp, 0, 0, 0, 0, xmitq);
+}
+
 /* tipc_link_build_nack_msg: prepare link nack message for transmission
  */
 static void tipc_link_build_nack_msg(struct tipc_link *l,
@@ -1077,27 +1095,34 @@ int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
 {
        struct sk_buff_head *defq = &l->deferdq;
        struct tipc_msg *hdr;
-       u16 seqno, rcv_nxt;
+       u16 seqno, rcv_nxt, win_lim;
        int rc = 0;
 
        do {
                hdr = buf_msg(skb);
                seqno = msg_seqno(hdr);
                rcv_nxt = l->rcv_nxt;
+               win_lim = rcv_nxt + TIPC_MAX_LINK_WIN;
 
                /* Verify and update link state */
                if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
                        return tipc_link_proto_rcv(l, skb, xmitq);
 
                if (unlikely(!link_is_up(l))) {
-                       rc = tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
-                       if (!link_is_up(l))
-                               goto drop;
+                       if (l->state == LINK_ESTABLISHING)
+                               rc = TIPC_LINK_UP_EVT;
+                       goto drop;
                }
 
                /* Don't send probe at next timeout expiration */
                l->silent_intv_cnt = 0;
 
+               /* Drop if outside receive window */
+               if (unlikely(less(seqno, rcv_nxt) || more(seqno, win_lim))) {
+                       l->stats.duplicates++;
+                       goto drop;
+               }
+
                /* Forward queues and wake up waiting users */
                if (likely(tipc_link_release_pkts(l, msg_ack(hdr)))) {
                        tipc_link_advance_backlog(l, xmitq);
@@ -1105,29 +1130,20 @@ int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
                                link_prepare_wakeup(l);
                }
 
-               /* Defer reception if there is a gap in the sequence */
-               if (unlikely(less(rcv_nxt, seqno))) {
-                       __tipc_skb_queue_sorted(defq, skb);
+               /* Defer delivery if sequence gap */
+               if (unlikely(seqno != rcv_nxt)) {
+                       __tipc_skb_queue_sorted(defq, seqno, skb);
                        tipc_link_build_nack_msg(l, xmitq);
                        break;
                }
 
-               /* Drop if packet already received */
-               if (unlikely(more(rcv_nxt, seqno))) {
-                       l->stats.duplicates++;
-                       goto drop;
-               }
-
-               /* Packet can be delivered */
+               /* Deliver packet */
                l->rcv_nxt++;
                l->stats.recv_info++;
-
                if (!tipc_data_input(l, skb, l->inputq))
                        rc = tipc_link_input(l, skb, l->inputq);
-               if (rc)
+               if (unlikely(rc))
                        break;
-
-               /* Ack at regular intervals */
                if (unlikely(++l->rcv_unacked >= TIPC_MIN_LINK_WIN))
                        tipc_link_build_ack_msg(l, xmitq);
 
@@ -1340,6 +1356,7 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
        u16 peers_tol = msg_link_tolerance(hdr);
        u16 peers_prio = msg_linkprio(hdr);
        u16 rcv_nxt = l->rcv_nxt;
+       int mtyp = msg_type(hdr);
        char *if_name;
        int rc = 0;
 
@@ -1349,7 +1366,7 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
        if (link_own_addr(l) > msg_prevnode(hdr))
                l->net_plane = msg_net_plane(hdr);
 
-       switch (msg_type(hdr)) {
+       switch (mtyp) {
        case RESET_MSG:
 
                /* Ignore duplicate RESET with old session number */
@@ -1376,12 +1393,14 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
                if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
                        l->priority = peers_prio;
 
-               if (msg_type(hdr) == RESET_MSG) {
-                       rc |= tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
-               } else if (!link_is_up(l)) {
-                       tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
-                       rc |= tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
-               }
+               /* ACTIVATE_MSG serves as PEER_RESET if link is already down */
+               if ((mtyp == RESET_MSG) || !link_is_up(l))
+                       rc = tipc_link_fsm_evt(l, LINK_PEER_RESET_EVT);
+
+               /* ACTIVATE_MSG takes up link if it was already locally reset */
+               if ((mtyp == ACTIVATE_MSG) && (l->state == LINK_ESTABLISHING))
+                       rc = TIPC_LINK_UP_EVT;
+
                l->peer_session = msg_session(hdr);
                l->peer_bearer_id = msg_bearer_id(hdr);
                if (l->mtu > msg_max_pkt(hdr))
@@ -1398,9 +1417,12 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
                l->stats.recv_states++;
                if (msg_probe(hdr))
                        l->stats.recv_probes++;
-               rc = tipc_link_fsm_evt(l, LINK_ESTABLISH_EVT);
-               if (!link_is_up(l))
+
+               if (!link_is_up(l)) {
+                       if (l->state == LINK_ESTABLISHING)
+                               rc = TIPC_LINK_UP_EVT;
                        break;
+               }
 
                /* Send NACK if peer has sent pkts we haven't received yet */
                if (more(peers_snd_nxt, rcv_nxt) && !tipc_link_is_synching(l))