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* [PATCH] gro : fix reordering of packets in GRO library
@ 2022-10-13 10:18 Kumara Parameshwaran
  2022-10-13 10:20 ` kumaraparameshwaran rathinavel
                   ` (3 more replies)
  0 siblings, 4 replies; 24+ messages in thread
From: Kumara Parameshwaran @ 2022-10-13 10:18 UTC (permalink / raw)
  To: jiayu.hu; +Cc: dev, Kumara Parameshwaran

From: Kumara Parameshwaran <kumaraparamesh92@gmail.com>

When a TCP packet contains flags like PSH it is returned
immediately to the application though there might be packets of
the same flow in the GRO table. If PSH flag is set on a segment
packets upto the segment should be delivered immediately. But the
current implementation delivers the last arrived packet with PSH flag
set causing re-ordering

With this patch, if a packet does not contain only ACK flag and if there are
no previous packets for the flow the packet would be returned
immediately, else will be merged with the previous segment and the
flag on the last segment will be set on the entire segment.
This is the behaviour with linux stack as well

Signed-off-by: Kumara Parameshwaran <kumaraparamesh92@gmail.com>
---
v1:
    If the received packet is not a pure ACK packet, we check if
    there are any previous packets in the flow, if present we indulge
    the received packet also in the coalescing logic and update the flags
    of the last recived packet to the entire segment which would avoid
    re-ordering.

    Lets say a case where P1(PSH), P2(ACK), P3(ACK)  are received in burst mode,
    P1 contains PSH flag and since it does not contain any prior packets in the flow
    we copy it to unprocess_packets and P2(ACK) and P3(ACK) are merged together.
    In the existing case the  P2,P3 would be delivered as single segment first and the
    unprocess_packets will be copied later which will cause reordering. With the patch
    copy the unprocess packets first and then the packets from the GRO table.

    Testing done
    The csum test-pmd was modifited to support the following
    GET request of 10MB from client to server via test-pmd (static arp entries added in client
    and server). Enable GRO and TSO in test-pmd where the packets recived from the client mac
    would be sent to server mac and vice versa.
    In above testing, without the patch the client observerd re-ordering of 25 packets
    and with the patch there were no packet re-ordering observerd.

 lib/gro/gro_tcp4.c | 35 ++++++++++++++++++++++++++++-------
 lib/gro/rte_gro.c  | 18 +++++++++---------
 2 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/lib/gro/gro_tcp4.c b/lib/gro/gro_tcp4.c
index 8f5e800250..9ed891c253 100644
--- a/lib/gro/gro_tcp4.c
+++ b/lib/gro/gro_tcp4.c
@@ -188,6 +188,19 @@ update_header(struct gro_tcp4_item *item)
 			pkt->l2_len);
 }
 
+static inline void
+update_tcp_hdr_flags(struct rte_tcp_hdr *tcp_hdr, struct rte_mbuf *pkt)
+{
+	struct rte_ether_hdr *eth_hdr;
+	struct rte_ipv4_hdr *ipv4_hdr;
+	struct rte_tcp_hdr *merged_tcp_hdr;
+
+	eth_hdr = rte_pktmbuf_mtod(pkt, struct rte_ether_hdr *);
+	ipv4_hdr = (struct rte_ipv4_hdr *)((char *)eth_hdr + pkt->l2_len);
+	merged_tcp_hdr = (struct rte_tcp_hdr *)((char *)ipv4_hdr + pkt->l3_len);
+	merged_tcp_hdr->tcp_flags |= tcp_hdr->tcp_flags;
+}
+
 int32_t
 gro_tcp4_reassemble(struct rte_mbuf *pkt,
 		struct gro_tcp4_tbl *tbl,
@@ -206,6 +219,7 @@ gro_tcp4_reassemble(struct rte_mbuf *pkt,
 	uint32_t i, max_flow_num, remaining_flow_num;
 	int cmp;
 	uint8_t find;
+	uint32_t start_idx;
 
 	/*
 	 * Don't process the packet whose TCP header length is greater
@@ -219,12 +233,6 @@ gro_tcp4_reassemble(struct rte_mbuf *pkt,
 	tcp_hdr = (struct rte_tcp_hdr *)((char *)ipv4_hdr + pkt->l3_len);
 	hdr_len = pkt->l2_len + pkt->l3_len + pkt->l4_len;
 
-	/*
-	 * Don't process the packet which has FIN, SYN, RST, PSH, URG, ECE
-	 * or CWR set.
-	 */
-	if (tcp_hdr->tcp_flags != RTE_TCP_ACK_FLAG)
-		return -1;
 	/*
 	 * Don't process the packet whose payload length is less than or
 	 * equal to 0.
@@ -263,12 +271,21 @@ gro_tcp4_reassemble(struct rte_mbuf *pkt,
 		if (tbl->flows[i].start_index != INVALID_ARRAY_INDEX) {
 			if (is_same_tcp4_flow(tbl->flows[i].key, key)) {
 				find = 1;
+				start_idx = tbl->flows[i].start_index;
 				break;
 			}
 			remaining_flow_num--;
 		}
 	}
 
+	if (tcp_hdr->tcp_flags != RTE_TCP_ACK_FLAG) {
+		if (find)
+			/* Since PSH flag is set, start time will be set to 0 so it will be flushed immediately */
+			tbl->items[start_idx].start_time = 0;
+		else
+			return -1;
+	}
+
 	/*
 	 * Fail to find a matched flow. Insert a new flow and store the
 	 * packet into the flow.
@@ -303,8 +320,12 @@ gro_tcp4_reassemble(struct rte_mbuf *pkt,
 				is_atomic);
 		if (cmp) {
 			if (merge_two_tcp4_packets(&(tbl->items[cur_idx]),
-						pkt, cmp, sent_seq, ip_id, 0))
+						pkt, cmp, sent_seq, ip_id, 0)) {
+				if (tbl->items[cur_idx].start_time == 0)
+					update_tcp_hdr_flags(tcp_hdr, tbl->items[cur_idx].firstseg);
 				return 1;
+			}
+
 			/*
 			 * Fail to merge the two packets, as the packet
 			 * length is greater than the max value. Store
diff --git a/lib/gro/rte_gro.c b/lib/gro/rte_gro.c
index e35399fd42..87c5502dce 100644
--- a/lib/gro/rte_gro.c
+++ b/lib/gro/rte_gro.c
@@ -283,10 +283,17 @@ rte_gro_reassemble_burst(struct rte_mbuf **pkts,
 	if ((nb_after_gro < nb_pkts)
 		 || (unprocess_num < nb_pkts)) {
 		i = 0;
+		/* Copy unprocessed packets */
+		if (unprocess_num > 0) {
+			memcpy(&pkts[i], unprocess_pkts,
+					sizeof(struct rte_mbuf *) *
+					unprocess_num);
+			i = unprocess_num;
+		}
 		/* Flush all packets from the tables */
 		if (do_vxlan_tcp_gro) {
-			i = gro_vxlan_tcp4_tbl_timeout_flush(&vxlan_tcp_tbl,
-					0, pkts, nb_pkts);
+			i += gro_vxlan_tcp4_tbl_timeout_flush(&vxlan_tcp_tbl,
+					0, &pkts[i], nb_pkts - i);
 		}
 
 		if (do_vxlan_udp_gro) {
@@ -304,13 +311,6 @@ rte_gro_reassemble_burst(struct rte_mbuf **pkts,
 			i += gro_udp4_tbl_timeout_flush(&udp_tbl, 0,
 					&pkts[i], nb_pkts - i);
 		}
-		/* Copy unprocessed packets */
-		if (unprocess_num > 0) {
-			memcpy(&pkts[i], unprocess_pkts,
-					sizeof(struct rte_mbuf *) *
-					unprocess_num);
-		}
-		nb_after_gro = i + unprocess_num;
 	}
 
 	return nb_after_gro;
-- 
2.25.1


^ permalink raw reply	[flat|nested] 24+ messages in thread
* [PATCH] gro: fix the chain index in insert_new_item for more than 2 packets
@ 2022-09-07  8:59 Kumara Parameshwaran
  2022-11-01  7:03 ` [PATCH v5] gro : fix reordering of packets in GRO library Kumara Parameshwaran
  0 siblings, 1 reply; 24+ messages in thread
From: Kumara Parameshwaran @ 2022-09-07  8:59 UTC (permalink / raw)
  To: jiayu.hu; +Cc: dev, Kumara Parameshwaran

From: Kumara Parameshwaran <kumaraparamesh92@gmail.com>

When more than two packets are merged in a flow, and if we receive
a 3rd packet which is matching the sequence of the 2nd packet the
prev_idx will be 1 and not 2, hence resulting in packet re-ordering

Signed-off-by: Kumara Parameshwaran <kumaraparamesh92@gmail.com>
---
V1:
	Initial changes to fix packet reordering issue when 
	more than 2 items are chained in a flow.
	Ex:
		3 mergeable TCP packets received in order.
		packet_0 - no flow found so insert the packet and new start
		index -> 0
		packet_1-> flow found. prev_idx, curr_index = 0. So merge works
		find packet_0->packet_1
		packet_3 flow found. prev_indx =0, curr_index = 1. Matching
		dequence numbers found but chained as
		packet_0->packet_2->packet_1

 lib/gro/gro_tcp4.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/gro/gro_tcp4.c b/lib/gro/gro_tcp4.c
index 7498c66141..9758e28fd5 100644
--- a/lib/gro/gro_tcp4.c
+++ b/lib/gro/gro_tcp4.c
@@ -305,7 +305,7 @@ gro_tcp4_reassemble(struct rte_mbuf *pkt,
 			 * length is greater than the max value. Store
 			 * the packet into the flow.
 			 */
-			if (insert_new_item(tbl, pkt, start_time, prev_idx,
+			if (insert_new_item(tbl, pkt, start_time, cur_idx,
 						sent_seq, ip_id, is_atomic) ==
 					INVALID_ARRAY_INDEX)
 				return -1;
-- 
2.25.1


^ permalink raw reply	[flat|nested] 24+ messages in thread

end of thread, other threads:[~2024-02-12 14:30 UTC | newest]

Thread overview: 24+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-10-13 10:18 [PATCH] gro : fix reordering of packets in GRO library Kumara Parameshwaran
2022-10-13 10:20 ` kumaraparameshwaran rathinavel
2022-10-28  8:09 ` [PATCH v2] " Kumara Parameshwaran
2022-10-28  8:27 ` [PATCH v3] " Kumara Parameshwaran
2022-10-28  9:51 ` [PATCH v4] " Kumara Parameshwaran
2022-11-01  7:05   ` [PATCH v5] " Kumara Parameshwaran
2023-06-19 13:25     ` Thomas Monjalon
2023-06-20  7:35     ` Hu, Jiayu
2023-06-21  8:47       ` kumaraparameshwaran rathinavel
2023-06-30 11:32       ` kumaraparameshwaran rathinavel
2023-12-08 17:54     ` [PATCH v6] gro: fix reordering of packets in GRO layer Kumara Parameshwaran
2023-12-08 18:05     ` [PATCH v7] " Kumara Parameshwaran
2023-12-08 18:12     ` [PATCH v8] " Kumara Parameshwaran
2023-12-08 18:17     ` [PATCH v9] " Kumara Parameshwaran
2024-01-04 15:49       ` 胡嘉瑜
2024-01-07 11:21       ` [PATCH v10] " Kumara Parameshwaran
2024-01-07 11:29       ` [PATCH v11] " Kumara Parameshwaran
2024-01-07 17:20         ` Stephen Hemminger
2024-01-08 16:11           ` kumaraparameshwaran rathinavel
2024-01-08 15:50       ` [PATCH v12] " Kumara Parameshwaran
2024-01-08 16:04       ` [PATCH v13] " Kumara Parameshwaran
2024-01-16 14:28         ` 胡嘉瑜
2024-02-12 14:30           ` Thomas Monjalon
  -- strict thread matches above, loose matches on Subject: below --
2022-09-07  8:59 [PATCH] gro: fix the chain index in insert_new_item for more than 2 packets Kumara Parameshwaran
2022-11-01  7:03 ` [PATCH v5] gro : fix reordering of packets in GRO library Kumara Parameshwaran

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