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path: root/net/dccp/ccids/lib/packet_history.c
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Diffstat (limited to 'net/dccp/ccids/lib/packet_history.c')
-rw-r--r--net/dccp/ccids/lib/packet_history.c82
1 files changed, 82 insertions, 0 deletions
diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c
index e2576b45ac0..d3f9d205383 100644
--- a/net/dccp/ccids/lib/packet_history.c
+++ b/net/dccp/ccids/lib/packet_history.c
@@ -224,6 +224,88 @@ trim_history:
EXPORT_SYMBOL_GPL(dccp_rx_hist_add_packet);
+u64 dccp_rx_hist_detect_loss(struct list_head *rx_list,
+ struct list_head *li_list, u8 *win_loss)
+{
+ struct dccp_rx_hist_entry *entry, *next, *packet;
+ struct dccp_rx_hist_entry *a_loss = NULL;
+ struct dccp_rx_hist_entry *b_loss = NULL;
+ u64 seq_loss = DCCP_MAX_SEQNO + 1;
+ u8 num_later = TFRC_RECV_NUM_LATE_LOSS;
+
+ list_for_each_entry_safe(entry, next, rx_list, dccphrx_node) {
+ if (num_later == 0) {
+ b_loss = entry;
+ break;
+ } else if (dccp_rx_hist_entry_data_packet(entry))
+ --num_later;
+ }
+
+ if (b_loss == NULL)
+ goto out;
+
+ num_later = 1;
+ list_for_each_entry_safe_continue(entry, next, rx_list, dccphrx_node) {
+ if (num_later == 0) {
+ a_loss = entry;
+ break;
+ } else if (dccp_rx_hist_entry_data_packet(entry))
+ --num_later;
+ }
+
+ if (a_loss == NULL) {
+ if (list_empty(li_list)) {
+ /* no loss event have occured yet */
+ LIMIT_NETDEBUG("%s: TODO: find a lost data packet by "
+ "comparing to initial seqno\n",
+ __FUNCTION__);
+ goto out;
+ } else {
+ LIMIT_NETDEBUG("%s: Less than 4 data pkts in history!",
+ __FUNCTION__);
+ goto out;
+ }
+ }
+
+ /* Locate a lost data packet */
+ entry = packet = b_loss;
+ list_for_each_entry_safe_continue(entry, next, rx_list, dccphrx_node) {
+ u64 delta = dccp_delta_seqno(entry->dccphrx_seqno,
+ packet->dccphrx_seqno);
+
+ if (delta != 0) {
+ if (dccp_rx_hist_entry_data_packet(packet))
+ --delta;
+ /*
+ * FIXME: check this, probably this % usage is because
+ * in earlier drafts the ndp count was just 8 bits
+ * long, but now it cam be up to 24 bits long.
+ */
+#if 0
+ if (delta % DCCP_NDP_LIMIT !=
+ (packet->dccphrx_ndp -
+ entry->dccphrx_ndp) % DCCP_NDP_LIMIT)
+#endif
+ if (delta != packet->dccphrx_ndp - entry->dccphrx_ndp) {
+ seq_loss = entry->dccphrx_seqno;
+ dccp_inc_seqno(&seq_loss);
+ }
+ }
+ packet = entry;
+ if (packet == a_loss)
+ break;
+ }
+out:
+ if (seq_loss != DCCP_MAX_SEQNO + 1)
+ *win_loss = a_loss->dccphrx_ccval;
+ else
+ *win_loss = 0; /* Paranoia */
+
+ return seq_loss;
+}
+
+EXPORT_SYMBOL_GPL(dccp_rx_hist_detect_loss);
+
struct dccp_tx_hist *dccp_tx_hist_new(const char *name)
{
struct dccp_tx_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC);