[DCCP]: Introduce dccp_rx_hist_find_entry

This adds a new function dccp_rx_hist_find_entry.

Signed off by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/dccp/ccids/lib/packet_history.c

@@ -365,6 +365,25 @@ struct dccp_tx_hist_entry *
 
 EXPORT_SYMBOL_GPL(dccp_tx_hist_find_entry);
 
+int dccp_rx_hist_find_entry(const struct list_head *list, const u64 seq,
+   u8 *ccval)
+{
+	struct dccp_rx_hist_entry *packet = NULL, *entry;
+
+	list_for_each_entry(entry, list, dccphrx_node)
+		if (entry->dccphrx_seqno == seq) {
+			packet = entry;
+			break;
+		}
+
+	if (packet)
+		*ccval = packet->dccphrx_ccval;
+
+	return packet != NULL;
+}
+
+EXPORT_SYMBOL_GPL(dccp_rx_hist_find_entry);
+
 void dccp_tx_hist_purge_older(struct dccp_tx_hist *hist,
 			      struct list_head *list,
 			      struct dccp_tx_hist_entry *packet)

net/dccp/ccids/lib/packet_history.h

@@ -106,6 +106,8 @@ static inline void dccp_tx_hist_entry_delete(struct dccp_tx_hist *hist,
 extern struct dccp_tx_hist_entry *
 			dccp_tx_hist_find_entry(const struct list_head *list,
 						const u64 seq);
+extern int dccp_rx_hist_find_entry(const struct list_head *list, const u64 seq,
+   u8 *ccval);
 
 static inline void dccp_tx_hist_add_entry(struct list_head *list,
 					  struct dccp_tx_hist_entry *entry)