| Message ID | 1372759229-15178-4-git-send-email-jchapman@katalix.com |
|---|---|
| State | Superseded, archived |
| Delegated to: | David Miller |
| Headers | show |
Hello. On 02-07-2013 14:00, James Chapman wrote: > If L2TP data sequence numbers are enabled and reordering is not > enabled, data reception stops if a packet is lost since the kernel > waits for a sequence number that is never resent. (When reordering is > enabled, data reception restarts when the reorder timeout expires.) If > no reorder timeout is set, we should count the number of in-sequence > packets after the out-of-sequence (OOS) condition is detected, and reset > sequence number state after a number of such packets are received. > For now, the number of in-sequence packets while in OOS state which > cause the sequence number state to be reset is hard-coded to 5. This > could be configurable later. > Signed-off-by: James Chapman <jchapman@katalix.com> > --- > net/l2tp/l2tp_core.c | 37 ++++++++++++++++++++++++++++++++----- > net/l2tp/l2tp_core.h | 3 +++ > 2 files changed, 35 insertions(+), 5 deletions(-) > diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c > index cc7ece9..f572e93 100644 > --- a/net/l2tp/l2tp_core.c > +++ b/net/l2tp/l2tp_core.c > @@ -572,12 +572,34 @@ static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb) [...] > + u32 nr_oos = L2TP_SKB_CB(skb)->ns; > + u32 nr_next = (session->nr_oos + 1) & session->nr_max; > + > + if (nr_oos == nr_next) > + session->nr_oos_count++; > + else > + session->nr_oos_count = 0; > + > + session->nr_oos = nr_oos; > + if (session->nr_oos_count > session->nr_oos_count_max) { > + session->reorder_skip = 1; > + l2tp_dbg(session, L2TP_MSG_SEQ, > + "%s: %d oos packets received. " > + "Resetting sequence numbers\n", Same comment about the long message string. Not breaking such strings facilitates grepping in the kernel for them. In theory, checkpatch.pl should have complained here, but it might not have recognized the function. If it complains about long string, just ignore it. WBR, Sergei -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index cc7ece9..f572e93 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -572,12 +572,34 @@ static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb) * reorder queue, in order of ns. */ l2tp_recv_queue_skb(session, skb); + goto out; + } + + /* Packet reordering disabled. Discard out-of-sequence packets, while + * tracking the number if in-sequence packets after the first OOS packet + * is seen. After nr_oos_count_max in-sequence packets, reset the + * sequence number to re-enable packet reception. + */ + if (L2TP_SKB_CB(skb)->ns == session->nr) { + skb_queue_tail(&session->reorder_q, skb); } else { - /* Packet reordering disabled. Discard out-of-sequence - * packets - */ - if ((L2TP_SKB_CB(skb)->ns != session->nr) && - (!session->reorder_skip)) { + u32 nr_oos = L2TP_SKB_CB(skb)->ns; + u32 nr_next = (session->nr_oos + 1) & session->nr_max; + + if (nr_oos == nr_next) + session->nr_oos_count++; + else + session->nr_oos_count = 0; + + session->nr_oos = nr_oos; + if (session->nr_oos_count > session->nr_oos_count_max) { + session->reorder_skip = 1; + l2tp_dbg(session, L2TP_MSG_SEQ, + "%s: %d oos packets received. " + "Resetting sequence numbers\n", + session->name, session->nr_oos_count); + } + if (!session->reorder_skip) { atomic_long_inc(&session->stats.rx_seq_discards); l2tp_dbg(session, L2TP_MSG_SEQ, "%s: oos pkt %u len %d discarded, " @@ -590,6 +612,7 @@ static int l2tp_recv_data_seq(struct l2tp_session *session, struct sk_buff *skb) skb_queue_tail(&session->reorder_q, skb); } +out: return 0; discard: @@ -1853,6 +1876,10 @@ struct l2tp_session *l2tp_session_create(int priv_size, struct l2tp_tunnel *tunn else session->nr_max = 0xffffff; session->nr_window_size = session->nr_max / 2; + session->nr_oos_count_max = 4; + + /* Use NR of first received packet */ + session->reorder_skip = 1; sprintf(&session->name[0], "sess %u/%u", tunnel->tunnel_id, session->session_id); diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h index 4b9a3b7..66a559b 100644 --- a/net/l2tp/l2tp_core.h +++ b/net/l2tp/l2tp_core.h @@ -104,6 +104,9 @@ struct l2tp_session { struct sk_buff_head reorder_q; /* receive reorder queue */ u32 nr_max; /* max NR. Depends on tunnel */ u32 nr_window_size; /* NR window size */ + u32 nr_oos; /* NR of last OOS packet */ + int nr_oos_count; /* For OOS recovery */ + int nr_oos_count_max; struct hlist_node hlist; /* Hash list node */ atomic_t ref_count;
If L2TP data sequence numbers are enabled and reordering is not enabled, data reception stops if a packet is lost since the kernel waits for a sequence number that is never resent. (When reordering is enabled, data reception restarts when the reorder timeout expires.) If no reorder timeout is set, we should count the number of in-sequence packets after the out-of-sequence (OOS) condition is detected, and reset sequence number state after a number of such packets are received. For now, the number of in-sequence packets while in OOS state which cause the sequence number state to be reset is hard-coded to 5. This could be configurable later. Signed-off-by: James Chapman <jchapman@katalix.com> --- net/l2tp/l2tp_core.c | 37 ++++++++++++++++++++++++++++++++----- net/l2tp/l2tp_core.h | 3 +++ 2 files changed, 35 insertions(+), 5 deletions(-)