[dpdk-dev] [PATCH 1/2] examples/l2fwd: Add new option to enable/disable MAC addresses tweaking

[Maxime Coquelin <maxime.coquelin@redhat.com>]

l2fwd could be useful for testing virtual devices without the need
of physical ones.

To achieve this, this patch adds a new option to enable/disable the
MAC addresses tweaking done at forwarding time: --[no-]mac-tweaking

By default, MAC address tweaking remains enabled, to keep consistency
with previous usage.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 examples/l2fwd/main.c | 39 +++++++++++++++++++++++++++++----------
 1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/examples/l2fwd/main.c b/examples/l2fwd/main.c
index 8897921..2693be1 100644
--- a/examples/l2fwd/main.c
+++ b/examples/l2fwd/main.c
@@ -74,6 +74,9 @@
 
 static volatile bool force_quit;
 
+/* MAC tweaking enabled by default */
+static int mac_tweaking = 1;
+
 #define RTE_LOGTYPE_L2FWD RTE_LOGTYPE_USER1
 
 #define NB_MBUF   8192
@@ -186,23 +189,32 @@ print_stats(void)
 }
 
 static void
-l2fwd_simple_forward(struct rte_mbuf *m, unsigned portid)
+l2fwd_mac_tweaking(struct rte_mbuf *m, unsigned dest_portid)
 {
 	struct ether_hdr *eth;
 	void *tmp;
-	unsigned dst_port;
-	int sent;
-	struct rte_eth_dev_tx_buffer *buffer;
 
-	dst_port = l2fwd_dst_ports[portid];
 	eth = rte_pktmbuf_mtod(m, struct ether_hdr *);
 
 	/* 02:00:00:00:00:xx */
 	tmp = &eth->d_addr.addr_bytes[0];
-	*((uint64_t *)tmp) = 0x000000000002 + ((uint64_t)dst_port << 40);
+	*((uint64_t *)tmp) = 0x000000000002 + ((uint64_t)dest_portid << 40);
 
 	/* src addr */
-	ether_addr_copy(&l2fwd_ports_eth_addr[dst_port], &eth->s_addr);
+	ether_addr_copy(&l2fwd_ports_eth_addr[dest_portid], &eth->s_addr);
+}
+
+static void
+l2fwd_simple_forward(struct rte_mbuf *m, unsigned portid)
+{
+	unsigned dst_port;
+	int sent;
+	struct rte_eth_dev_tx_buffer *buffer;
+
+	dst_port = l2fwd_dst_ports[portid];
+
+	if (mac_tweaking)
+		l2fwd_mac_tweaking(m, dst_port);
 
 	buffer = tx_buffer[dst_port];
 	sent = rte_eth_tx_buffer(dst_port, 0, buffer, m);
@@ -322,7 +334,11 @@ l2fwd_usage(const char *prgname)
 	printf("%s [EAL options] -- -p PORTMASK [-q NQ]\n"
 	       "  -p PORTMASK: hexadecimal bitmask of ports to configure\n"
 	       "  -q NQ: number of queue (=ports) per lcore (default is 1)\n"
-		   "  -T PERIOD: statistics will be refreshed each PERIOD seconds (0 to disable, 10 default, 86400 maximum)\n",
+		   "  -T PERIOD: statistics will be refreshed each PERIOD seconds (0 to disable, 10 default, 86400 maximum)\n"
+		   "  --[no-]mac-tweaking: Enable or disable MAC addresses tweaking (enabled by default)\n"
+		   "      When enabled:\n"
+		   "       - The source MAC address is replaced by the TX port MAC address\n"
+		   "       - The destination MAC address is replaced by 02:00:00:00:00:TX_PORT_ID\n",
 	       prgname);
 }
 
@@ -386,6 +402,8 @@ l2fwd_parse_args(int argc, char **argv)
 	int option_index;
 	char *prgname = argv[0];
 	static struct option lgopts[] = {
+		{ "mac-tweaking", no_argument, &mac_tweaking, 1},
+		{ "no-mac-tweaking", no_argument, &mac_tweaking, 0},
 		{NULL, 0, 0, 0}
 	};
 
@@ -428,8 +446,7 @@ l2fwd_parse_args(int argc, char **argv)
 
 		/* long options */
 		case 0:
-			l2fwd_usage(prgname);
-			return -1;
+			break;
 
 		default:
 			l2fwd_usage(prgname);
@@ -542,6 +559,8 @@ main(int argc, char **argv)
 	if (ret < 0)
 		rte_exit(EXIT_FAILURE, "Invalid L2FWD arguments\n");
 
+	printf("MAC tweaking %s\n", mac_tweaking ? "enabled" : "disabled");
+
 	/* convert to number of cycles */
 	timer_period *= rte_get_timer_hz();
 
-- 
2.7.4