3 files changed, 64 insertions, 6 deletions

diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index 00fbb5c4b2ef..f48e5857210f 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -525,6 +525,10 @@ bool tipc_msg_reverse(u32 own_node,  struct sk_buff **skb, int err)
         if (hlen == SHORT_H_SIZE)
                 hlen = BASIC_H_SIZE;
 
+        /* Don't return data along with SYN+, - sender has a clone */
+        if (msg_is_syn(_hdr) && err == TIPC_ERR_OVERLOAD)
+                dlen = 0;
+
         /* Allocate new buffer to return */
         *skb = tipc_buf_acquire(hlen + dlen, GFP_ATOMIC);
         if (!*skb)
@@ -552,6 +556,22 @@ exit:
         return false;
 }
 
+bool tipc_msg_skb_clone(struct sk_buff_head *msg, struct sk_buff_head *cpy)
+{
+        struct sk_buff *skb, *_skb;
+
+        skb_queue_walk(msg, skb) {
+                _skb = skb_clone(skb, GFP_ATOMIC);
+                if (!_skb) {
+                        __skb_queue_purge(cpy);
+                        pr_err_ratelimited("Failed to clone buffer chain\n");
+                        return false;
+                }
+                __skb_queue_tail(cpy, _skb);
+        }
+        return true;
+}
+
 /**
  * tipc_msg_lookup_dest(): try to find new destination for named message
  * @skb: the buffer containing the message.
diff --git a/net/tipc/msg.h b/net/tipc/msg.h
index cd64d7b2a0fe..a2879e6ec5b6 100644
--- a/net/tipc/msg.h
+++ b/net/tipc/msg.h
@@ -980,6 +980,7 @@ bool tipc_msg_pskb_copy(u32 dst, struct sk_buff_head *msg,
                         struct sk_buff_head *cpy);
 void __tipc_skb_queue_sorted(struct sk_buff_head *list, u16 seqno,
                              struct sk_buff *skb);
+bool tipc_msg_skb_clone(struct sk_buff_head *msg, struct sk_buff_head *cpy);
 
 static inline u16 buf_seqno(struct sk_buff *skb)
 {
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 89d6dc0f456d..595c5001b28d 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -47,7 +47,7 @@
 #include "netlink.h"
 #include "group.h"
 
-#define CONN_TIMEOUT_DEFAULT    8000    /* default connect timeout = 8s */
+#define CONN_TIMEOUT_DEFAULT    8000    /* default connect timeout = 8s */
 #define CONN_PROBING_INTV       msecs_to_jiffies(3600000)  /* [ms] => 1 h */
 #define TIPC_FWD_MSG            1
 #define TIPC_MAX_PORT           0xffffffff
@@ -80,7 +80,6 @@ struct sockaddr_pair {
  * @publications: list of publications for port
  * @blocking_link: address of the congested link we are currently sleeping on
  * @pub_count: total # of publications port has made during its lifetime
- * @probing_state:
  * @conn_timeout: the time we can wait for an unresponded setup request
  * @dupl_rcvcnt: number of bytes counted twice, in both backlog and rcv queue
  * @cong_link_cnt: number of congested links
@@ -102,8 +101,8 @@ struct tipc_sock {
         struct list_head cong_links;
         struct list_head publications;
         u32 pub_count;
-        uint conn_timeout;
         atomic_t dupl_rcvcnt;
+        u16 conn_timeout;
         bool probe_unacked;
         u16 cong_link_cnt;
         u16 snt_unacked;
@@ -507,6 +506,9 @@ static void __tipc_shutdown(struct socket *sock, int error)
         tipc_wait_for_cond(sock, &timeout, (!tsk->cong_link_cnt &&
                                             !tsk_conn_cong(tsk)));
 
+        /* Remove any pending SYN message */
+        __skb_queue_purge(&sk->sk_write_queue);
+
         /* Reject all unreceived messages, except on an active connection
          * (which disconnects locally & sends a 'FIN+' to peer).
          */
@@ -1362,6 +1364,8 @@ static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dlen)
         rc = tipc_msg_build(hdr, m, 0, dlen, mtu, &pkts);
         if (unlikely(rc != dlen))
                 return rc;
+        if (unlikely(syn && !tipc_msg_skb_clone(&pkts, &sk->sk_write_queue)))
+                return -ENOMEM;
 
         rc = tipc_node_xmit(net, &pkts, dnode, tsk->portid);
         if (unlikely(rc == -ELINKCONG)) {
@@ -1491,6 +1495,7 @@ static void tipc_sk_finish_conn(struct tipc_sock *tsk, u32 peer_port,
         tipc_node_add_conn(net, peer_node, tsk->portid, peer_port);
         tsk->max_pkt = tipc_node_get_mtu(net, peer_node, tsk->portid);
         tsk->peer_caps = tipc_node_get_capabilities(net, peer_node);
+        __skb_queue_purge(&sk->sk_write_queue);
         if (tsk->peer_caps & TIPC_BLOCK_FLOWCTL)
                 return;
 
@@ -1977,6 +1982,7 @@ static bool tipc_sk_filter_connect(struct tipc_sock *tsk, struct sk_buff *skb)
         u32 oport = msg_origport(hdr);
         u32 onode = msg_orignode(hdr);
         int err = msg_errcode(hdr);
+        unsigned long delay;
 
         if (unlikely(msg_mcast(hdr)))
                 return false;
@@ -2001,8 +2007,18 @@ static bool tipc_sk_filter_connect(struct tipc_sock *tsk, struct sk_buff *skb)
                 if (oport != pport || onode != pnode)
                         return false;
 
-                /* Rejected SYN - abort */
-                break;
+                /* Rejected SYN */
+                if (err != TIPC_ERR_OVERLOAD)
+                        break;
+
+                /* Prepare for new setup attempt if we have a SYN clone */
+                if (skb_queue_empty(&sk->sk_write_queue))
+                        break;
+                get_random_bytes(&delay, 2);
+                delay %= (tsk->conn_timeout / 4);
+                delay = msecs_to_jiffies(delay + 100);
+                sk_reset_timer(sk, &sk->sk_timer, jiffies + delay);
+                return false;
         case TIPC_OPEN:
         case TIPC_DISCONNECTING:
                 return false;
@@ -2561,12 +2577,26 @@ static void tipc_sk_check_probing_state(struct sock *sk,
         sk_reset_timer(sk, &sk->sk_timer, jiffies + CONN_PROBING_INTV);
 }
 
+static void tipc_sk_retry_connect(struct sock *sk, struct sk_buff_head *list)
+{
+        struct tipc_sock *tsk = tipc_sk(sk);
+
+        /* Try again later if dest link is congested */
+        if (tsk->cong_link_cnt) {
+                sk_reset_timer(sk, &sk->sk_timer, msecs_to_jiffies(100));
+                return;
+        }
+        /* Prepare SYN for retransmit */
+        tipc_msg_skb_clone(&sk->sk_write_queue, list);
+}
+
 static void tipc_sk_timeout(struct timer_list *t)
 {
         struct sock *sk = from_timer(sk, t, sk_timer);
         struct tipc_sock *tsk = tipc_sk(sk);
         u32 pnode = tsk_peer_node(tsk);
         struct sk_buff_head list;
+        int rc = 0;
 
         skb_queue_head_init(&list);
         bh_lock_sock(sk);
@@ -2580,12 +2610,19 @@ static void tipc_sk_timeout(struct timer_list *t)
 
         if (sk->sk_state == TIPC_ESTABLISHED)
                 tipc_sk_check_probing_state(sk, &list);
+        else if (sk->sk_state == TIPC_CONNECTING)
+                tipc_sk_retry_connect(sk, &list);
 
         bh_unlock_sock(sk);
 
         if (!skb_queue_empty(&list))
-                tipc_node_xmit(sock_net(sk), &list, pnode, tsk->portid);
+                rc = tipc_node_xmit(sock_net(sk), &list, pnode, tsk->portid);
 
+        /* SYN messages may cause link congestion */
+        if (rc == -ELINKCONG) {
+                tipc_dest_push(&tsk->cong_links, pnode, 0);
+                tsk->cong_link_cnt = 1;
+        }
         sock_put(sk);
 }