[PATCH 4/6] app/dumpcap: fix capturing on multiple interfaces

[Ben Magistro <koncept1@gmail.com>]

When selecting interfaces to capture traffic on, only the last interface
specified was being preserved for selection. This turns the interface
argument into an array allowing multiple interfaces to be selected.

This also adds checks for the capture format so that if multiple interfaces
are selected, the interface information is included in the capture file.

Fixes: 7f3623a ("app/dumpcap: fix select interface")
Cc: arshdeep.kaur@intel.com
Cc: stephen@networkplumber.org
Cc: stable@dpdk.org

Signed-off-by: Ben Magistro <koncept1@gmail.com>
---
 app/dumpcap/main.c | 47 +++++++++++++++++++++++++++++++++-------------
 1 file changed, 34 insertions(+), 13 deletions(-)

diff --git a/app/dumpcap/main.c b/app/dumpcap/main.c
index 26c641df61..dc4d69ff6b 100644
--- a/app/dumpcap/main.c
+++ b/app/dumpcap/main.c
@@ -65,8 +65,8 @@ static const char *file_prefix;
 static uint32_t snaplen = RTE_MBUF_DEFAULT_BUF_SIZE;
 static bool dump_bpf;
 static bool show_interfaces;
-static bool select_interfaces;
-const char *interface_arg;
+static uint8_t interface_arg_count = 0; /* count of interfaces configured via -i */
+static const char *interface_arg[RTE_MAX_ETHPORTS]; /*array of interface parameters */
 
 static struct {
 	uint64_t  duration;	/* nanoseconds */
@@ -242,7 +242,6 @@ static void set_default_interface(void)
 		add_interface(p, name);
 		return;
 	}
-	rte_exit(EXIT_FAILURE, "No usable interfaces found\n");
 }
 
 /* Lookup interface by name or port and add it to the list */
@@ -265,6 +264,32 @@ static void select_interface(const char *arg)
 	}
 }
 
+/**
+ * builds list of interfacs that capture will occur on
+ * this also validates the save format based on the number of interfaces
+ */
+static void collect_interfaces(void)
+{
+	uint8_t active;
+	struct interface *intf;
+
+	active = 0;
+
+	if (interface_arg_count == 0)
+		set_default_interface();
+	else
+		for (uint8_t i = 0; i < interface_arg_count; ++i)
+			select_interface(interface_arg[i]);
+
+	TAILQ_FOREACH(intf, &interfaces, next)
+		active++;
+
+	if ((!use_pcapng) && (active > 1)) {
+		printf("Requested pcap format, but options require pcapng; overriding\n");
+		use_pcapng = true;
+	}
+}
+
 /* Display list of possible interfaces that can be used. */
 static void dump_interfaces(void)
 {
@@ -406,8 +431,8 @@ static void parse_opts(int argc, char **argv)
 			usage();
 			exit(0);
 		case 'i':
-			select_interfaces = true;
-			interface_arg = optarg;
+			interface_arg_count++;
+			interface_arg[interface_arg_count - 1] = optarg;
 			break;
 		case 'n':
 			use_pcapng = true;
@@ -840,21 +865,17 @@ int main(int argc, char **argv)
 	parse_opts(argc, argv);
 	dpdk_init();
 
+	if (rte_eth_dev_count_avail() == 0)
+		rte_exit(EXIT_FAILURE, "No usable ports found\n");
+
 	if (show_interfaces)
 		dump_interfaces();
 
-	if (rte_eth_dev_count_avail() == 0)
-		rte_exit(EXIT_FAILURE, "No Ethernet ports found\n");
-
-	if (select_interfaces)
-		select_interface(interface_arg);
+	collect_interfaces();
 
 	if (filter_str)
 		compile_filter();
 
-	if (TAILQ_EMPTY(&interfaces))
-		set_default_interface();
-
 	r = create_ring();
 	mp = create_mempool();
 	out = create_output();
-- 
2.27.0