tipc: eliminate unnecessary linearization of incoming buffers

Currently, TIPC linearizes all incoming buffers directly at reception
before passing them upwards in the stack. This is clearly a waste of
CPU resources, and must be avoided.

In this commit, we eliminate this unnecessary linearization. We still
ensure that at least the message header is linear, and that the buffer
is linearized where this is still needed, i.e. when unbundling and when
reversing messages.

In addition, we ensure that fragmented messages are validated after
reassembly before delivering them upwards in the stack.

Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 944c8c663a2d9965958460569a8a7a8d46e815fc..8c6639d107fceccb842657f2f55b1ed120c2ec0e 100644 (file)
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1075,13 +1075,8 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr)
                if (unlikely(!tipc_msg_validate(skb)))
                        goto discard;
 
-               /* Ensure message data is a single contiguous unit */
-               if (unlikely(skb_linearize(skb)))
-                       goto discard;
-
                /* Handle arrival of a non-unicast link message */
                msg = buf_msg(skb);
-
                if (unlikely(msg_non_seq(msg))) {
                        if (msg_user(msg) ==  LINK_CONFIG)
                                tipc_disc_rcv(net, skb, b_ptr);

diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index 4a64caf6fa20c14e8ed0e123c4fb770fe050a35a..ff8c64cd1cd9c0a2760ab6880e49c3690283be5d 100644 (file)
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -165,6 +165,9 @@ int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
        }
 
        if (fragid == LAST_FRAGMENT) {
+               TIPC_SKB_CB(head)->validated = false;
+               if (unlikely(!tipc_msg_validate(head)))
+                       goto err;
                *buf = head;
                TIPC_SKB_CB(head)->tail = NULL;
                *headbuf = NULL;
@@ -172,7 +175,6 @@ int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
        }
        *buf = NULL;
        return 0;
-
 err:
        pr_warn_ratelimited("Unable to build fragment list\n");
        kfree_skb(*buf);
@@ -378,10 +380,14 @@ bool tipc_msg_bundle(struct sk_buff_head *list, struct sk_buff *skb, u32 mtu)
  */
 bool tipc_msg_extract(struct sk_buff *skb, struct sk_buff **iskb, int *pos)
 {
-       struct tipc_msg *msg = buf_msg(skb);
+       struct tipc_msg *msg;
        int imsz;
-       struct tipc_msg *imsg = (struct tipc_msg *)(msg_data(msg) + *pos);
+       struct tipc_msg *imsg;
 
+       if (unlikely(skb_linearize(skb)))
+               return false;
+       msg = buf_msg(skb);
+       imsg = (struct tipc_msg *)(msg_data(msg) + *pos);
        /* Is there space left for shortest possible message? */
        if (*pos > (msg_data_sz(msg) - SHORT_H_SIZE))
                goto none;
@@ -463,11 +469,11 @@ bool tipc_msg_reverse(u32 own_addr,  struct sk_buff *buf, u32 *dnode,
 
        if (skb_linearize(buf))
                goto exit;
+       msg = buf_msg(buf);
        if (msg_dest_droppable(msg))
                goto exit;
        if (msg_errcode(msg))
                goto exit;
-
        memcpy(&ohdr, msg, msg_hdr_sz(msg));
        imp = min_t(uint, imp + 1, TIPC_CRITICAL_IMPORTANCE);
        if (msg_isdata(msg))