1 files changed, 54 insertions, 1 deletions

diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index e525f8ce1dee..8be6e94a1ca9 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -1,7 +1,7 @@
 /*
  * net/tipc/msg.c: TIPC message header routines
  *
- * Copyright (c) 2000-2006, Ericsson AB
+ * Copyright (c) 2000-2006, 2014, Ericsson AB
  * Copyright (c) 2005, 2010-2011, Wind River Systems
  * All rights reserved.
  *
@@ -99,3 +99,56 @@ int tipc_msg_build(struct tipc_msg *hdr, struct iovec const *msg_sect,
         }
         return dsz;
 }
+
+/* tipc_buf_append(): Append a buffer to the fragment list of another buffer
+ * Let first buffer become head buffer
+ * Returns 1 and sets *buf to headbuf if chain is complete, otherwise 0
+ * Leaves headbuf pointer at NULL if failure
+ */
+int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
+{
+        struct sk_buff *head = *headbuf;
+        struct sk_buff *frag = *buf;
+        struct sk_buff *tail;
+        struct tipc_msg *msg = buf_msg(frag);
+        u32 fragid = msg_type(msg);
+        bool headstolen;
+        int delta;
+
+        skb_pull(frag, msg_hdr_sz(msg));
+
+        if (fragid == FIRST_FRAGMENT) {
+                if (head || skb_unclone(frag, GFP_ATOMIC))
+                        goto out_free;
+                head = *headbuf = frag;
+                skb_frag_list_init(head);
+                return 0;
+        }
+        if (!head)
+                goto out_free;
+        tail = TIPC_SKB_CB(head)->tail;
+        if (skb_try_coalesce(head, frag, &headstolen, &delta)) {
+                kfree_skb_partial(frag, headstolen);
+        } else {
+                if (!skb_has_frag_list(head))
+                        skb_shinfo(head)->frag_list = frag;
+                else
+                        tail->next = frag;
+                head->truesize += frag->truesize;
+                head->data_len += frag->len;
+                head->len += frag->len;
+                TIPC_SKB_CB(head)->tail = frag;
+        }
+        if (fragid == LAST_FRAGMENT) {
+                *buf = head;
+                TIPC_SKB_CB(head)->tail = NULL;
+                *headbuf = NULL;
+                return 1;
+        }
+        *buf = NULL;
+        return 0;
+out_free:
+        pr_warn_ratelimited("Unable to build fragment list\n");
+        kfree_skb(*buf);
+        return 0;
+}