[dpdk-dev] [PATCH v6 2/2] app/testpmd: fix txonly forwarding

[Alvin Zhang <alvinx.zhang@intel.com>]

When random number of Tx segments is enabled, because the actual
number of segments may be only one, the first segment of the Tx
packets must accommodate a complete being sending Eth/IP/UDP packet.

Besides, if multiple flow is enabled, the forwarding will update
the IP and UDP header, these headers shouldn't cross segments.
This also requires the first Tx segment can accommodate a complete
Eth/IP/UDP packet.

In addition, if time stamp is enabled, the forwarding needs more
Tx segment space for time stamp information.

This patch adds checks in beginning of forward engine to make sure
all above conditions are met.

Bugzilla ID: 797
Fixes: 79bec05b32b7 ("app/testpmd: add ability to split outgoing packets")
Cc: stable@dpdk.org

Signed-off-by: Alvin Zhang <alvinx.zhang@intel.com>
Acked-by: Xiaoyun Li <xiaoyun.li@intel.com>
---

v5: fixes a compilation issue
v6: update the commit summary and some logs
---
 app/test-pmd/txonly.c | 64 +++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 52 insertions(+), 12 deletions(-)

diff --git a/app/test-pmd/txonly.c b/app/test-pmd/txonly.c
index 386a4ff..8623239 100644
--- a/app/test-pmd/txonly.c
+++ b/app/test-pmd/txonly.c
@@ -40,6 +40,13 @@
 
 #include "testpmd.h"
 
+struct tx_timestamp {
+	rte_be32_t signature;
+	rte_be16_t pkt_idx;
+	rte_be16_t queue_idx;
+	rte_be64_t ts;
+};
+
 /* use RFC863 Discard Protocol */
 uint16_t tx_udp_src_port = 9;
 uint16_t tx_udp_dst_port = 9;
@@ -257,12 +264,7 @@
 
 	if (unlikely(timestamp_enable)) {
 		uint64_t skew = RTE_PER_LCORE(timestamp_qskew);
-		struct {
-			rte_be32_t signature;
-			rte_be16_t pkt_idx;
-			rte_be16_t queue_idx;
-			rte_be64_t ts;
-		} timestamp_mark;
+		struct tx_timestamp timestamp_mark;
 
 		if (unlikely(timestamp_init_req !=
 				RTE_PER_LCORE(timestamp_idone))) {
@@ -438,13 +440,22 @@
 static int
 tx_only_begin(portid_t pi)
 {
-	uint16_t pkt_data_len;
+	uint16_t pkt_hdr_len, pkt_data_len;
 	int dynf;
 
-	pkt_data_len = (uint16_t) (tx_pkt_length - (
-					sizeof(struct rte_ether_hdr) +
-					sizeof(struct rte_ipv4_hdr) +
-					sizeof(struct rte_udp_hdr)));
+	pkt_hdr_len = (uint16_t)(sizeof(struct rte_ether_hdr) +
+				 sizeof(struct rte_ipv4_hdr) +
+				 sizeof(struct rte_udp_hdr));
+	pkt_data_len = tx_pkt_length - pkt_hdr_len;
+
+	if ((tx_pkt_split == TX_PKT_SPLIT_RND || txonly_multi_flow) &&
+	    tx_pkt_seg_lengths[0] < pkt_hdr_len) {
+		TESTPMD_LOG(ERR,
+			    "Random segment number or multiple flow enabled, but tx_pkt_seg_lengths[0] %u < %u (needed)\n",
+			    tx_pkt_seg_lengths[0], pkt_hdr_len);
+		return -EINVAL;
+	}
+
 	setup_pkt_udp_ip_headers(&pkt_ip_hdr, &pkt_udp_hdr, pkt_data_len);
 
 	timestamp_enable = false;
@@ -463,8 +474,37 @@
 			   timestamp_mask &&
 			   timestamp_off >= 0 &&
 			   !rte_eth_read_clock(pi, &timestamp_initial[pi]);
-	if (timestamp_enable)
+
+	if (timestamp_enable) {
+		pkt_hdr_len += sizeof(struct tx_timestamp);
+
+		if (tx_pkt_split == TX_PKT_SPLIT_RND) {
+			if (tx_pkt_seg_lengths[0] < pkt_hdr_len) {
+				TESTPMD_LOG(ERR,
+					    "Time stamp and random segment number enabled, but tx_pkt_seg_lengths[0] %u < %u (needed)\n",
+					    tx_pkt_seg_lengths[0], pkt_hdr_len);
+				return -EINVAL;
+			}
+		} else {
+			uint16_t total = 0;
+			uint8_t i;
+
+			for (i = 0; i < tx_pkt_nb_segs; i++) {
+				total += tx_pkt_seg_lengths[i];
+				if (total >= pkt_hdr_len)
+					break;
+			}
+
+			if (total < pkt_hdr_len) {
+				TESTPMD_LOG(ERR,
+					    "No enough Tx segment space for time stamp info, total %u < %u (needed)\n",
+					    total, pkt_hdr_len);
+				return -EINVAL;
+			}
+		}
 		timestamp_init_req++;
+	}
+
 	/* Make sure all settings are visible on forwarding cores.*/
 	rte_wmb();
 	return 0;
-- 
1.8.3.1