selftests: nettest: Add --{force,no}-bind-key-ifindex

These options allow explicit control over the TCP_MD5SIG_FLAG_IFINDEX
flag instead of always setting it based on binding to an interface.

Do this by converting to getopt_long because nettest has too many
single-character flags already and getopt_long is widely used in
selftests.

Signed-off-by: Leonard Crestez <[e-mail]>
Reviewed-by: David Ahern <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

tools/testing/selftests/net/nettest.c

···
 #include <unistd.h>
 #include <time.h>
 #include <errno.h>
+#include <getopt.h>
 
 #include <linux/xfrm.h>
 #include <linux/ipsec.h>
···
 		struct sockaddr_in6 v6;
 	} md5_prefix;
 	unsigned int prefix_len;
+	/* 0: default, -1: force off, +1: force on */
+	int bind_key_ifindex;
 
 	/* expected addresses and device index for connection */
 	const char *expected_dev;
···
 	}
 	memcpy(&md5sig.tcpm_addr, addr, alen);
 
-	if (args->ifindex) {
+	if ((args->ifindex && args->bind_key_ifindex >= 0) || args->bind_key_ifindex >= 1) {
 		opt = TCP_MD5SIG_EXT;
 		md5sig.tcpm_flags |= TCP_MD5SIG_FLAG_IFINDEX;
 
 		md5sig.tcpm_ifindex = args->ifindex;
+		log_msg("TCP_MD5SIG_FLAG_IFINDEX set tcpm_ifindex=%d\n", md5sig.tcpm_ifindex);
+	} else {
+		log_msg("TCP_MD5SIG_FLAG_IFINDEX off\n", md5sig.tcpm_ifindex);
 	}
 
 	rc = setsockopt(sd, IPPROTO_TCP, opt, &md5sig, sizeof(md5sig));
···
 }
 
 #define GETOPT_STR  "sr:l:c:p:t:g:P:DRn:M:X:m:d:I:BN:O:SCi6xL:0:1:2:3:Fbq"
+#define OPT_FORCE_BIND_KEY_IFINDEX 1001
+#define OPT_NO_BIND_KEY_IFINDEX 1002
+
+static struct option long_opts[] = {
+	{"force-bind-key-ifindex", 0, 0, OPT_FORCE_BIND_KEY_IFINDEX},
+	{"no-bind-key-ifindex", 0, 0, OPT_NO_BIND_KEY_IFINDEX},
+	{0, 0, 0, 0}
+};
 
 static void print_usage(char *prog)
 {
···
 	"    -M password   use MD5 sum protection\n"
 	"    -X password   MD5 password for client mode\n"
 	"    -m prefix/len prefix and length to use for MD5 key\n"
+	"    --no-bind-key-ifindex: Force TCP_MD5SIG_FLAG_IFINDEX off\n"
+	"    --force-bind-key-ifindex: Force TCP_MD5SIG_FLAG_IFINDEX on\n"
+	"        (default: only if -I is passed)\n"
+	"\n"
 	"    -g grp        multicast group (e.g., 239.1.1.1)\n"
 	"    -i            interactive mode (default is echo and terminate)\n"
 	"\n"
···
 	 * process input args
 	 */
 
-	while ((rc = getopt(argc, argv, GETOPT_STR)) != -1) {
+	while ((rc = getopt_long(argc, argv, GETOPT_STR, long_opts, NULL)) != -1) {
 		switch (rc) {
 		case 'B':
 			both_mode = 1;
···
 			break;
 		case 'M':
 			args.password = optarg;
+			break;
+		case OPT_FORCE_BIND_KEY_IFINDEX:
+			args.bind_key_ifindex = 1;
+			break;
+		case OPT_NO_BIND_KEY_IFINDEX:
+			args.bind_key_ifindex = -1;
 			break;
 		case 'X':
 			args.client_pw = optarg;