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Diffstat (limited to 'net/tipc/msg.c')
-rw-r--r--net/tipc/msg.c59
1 files changed, 59 insertions, 0 deletions
diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index f48e5857210f..e6d49cdc61b4 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -244,6 +244,65 @@ bool tipc_msg_validate(struct sk_buff **_skb)
}
/**
+ * tipc_msg_fragment - build a fragment skb list for TIPC message
+ *
+ * @skb: TIPC message skb
+ * @hdr: internal msg header to be put on the top of the fragments
+ * @pktmax: max size of a fragment incl. the header
+ * @frags: returned fragment skb list
+ *
+ * Returns 0 if the fragmentation is successful, otherwise: -EINVAL
+ * or -ENOMEM
+ */
+int tipc_msg_fragment(struct sk_buff *skb, const struct tipc_msg *hdr,
+ int pktmax, struct sk_buff_head *frags)
+{
+ int pktno, nof_fragms, dsz, dmax, eat;
+ struct tipc_msg *_hdr;
+ struct sk_buff *_skb;
+ u8 *data;
+
+ /* Non-linear buffer? */
+ if (skb_linearize(skb))
+ return -ENOMEM;
+
+ data = (u8 *)skb->data;
+ dsz = msg_size(buf_msg(skb));
+ dmax = pktmax - INT_H_SIZE;
+ if (dsz <= dmax || !dmax)
+ return -EINVAL;
+
+ nof_fragms = dsz / dmax + 1;
+ for (pktno = 1; pktno <= nof_fragms; pktno++) {
+ if (pktno < nof_fragms)
+ eat = dmax;
+ else
+ eat = dsz % dmax;
+ /* Allocate a new fragment */
+ _skb = tipc_buf_acquire(INT_H_SIZE + eat, GFP_ATOMIC);
+ if (!_skb)
+ goto error;
+ skb_orphan(_skb);
+ __skb_queue_tail(frags, _skb);
+ /* Copy header & data to the fragment */
+ skb_copy_to_linear_data(_skb, hdr, INT_H_SIZE);
+ skb_copy_to_linear_data_offset(_skb, INT_H_SIZE, data, eat);
+ data += eat;
+ /* Update the fragment's header */
+ _hdr = buf_msg(_skb);
+ msg_set_fragm_no(_hdr, pktno);
+ msg_set_nof_fragms(_hdr, nof_fragms);
+ msg_set_size(_hdr, INT_H_SIZE + eat);
+ }
+ return 0;
+
+error:
+ __skb_queue_purge(frags);
+ __skb_queue_head_init(frags);
+ return -ENOMEM;
+}
+
+/**
* tipc_msg_build - create buffer chain containing specified header and data
* @mhdr: Message header, to be prepended to data
* @m: User message