libiproute: audit callgraph, shortcut error paths into die() functions.

Kill a few statics, made other globals smaller:
oneline is smallint, _SL_ is char

function                                             old     new   delta
print_tunnel                                         693     731     +38
print_route                                         1775    1777      +2
print_addrinfo                                      1495    1497      +2
ipaddr_list_or_flush                                2826    2828      +2
oneline                                                4       1      -3
_SL_                                                   4       1      -3
ipaddr_modify                                       1476    1472      -4
parse_address                                        124     119      -5
ip_parse_common_args                                 429     423      -6
on_off                                                53      46      -7
do_del_ioctl                                         113     106      -7
do_add_ioctl                                         120     113      -7
do_show                                              864     856      -8
iprule_list                                          157     148      -9
do_iptunnel                                          310     299     -11
do_add                                               143     126     -17
get_ctl_fd                                            95      76     -19
set_address                                          108      84     -24
ip_main                                              351     323     -28
static.ifr                                            32       -     -32
parse_args                                          1992    1949     -43
iproute_list_or_flush                               1673    1582     -91
do_iplink                                           1583    1485     -98
filter                                               280       -    -280
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 4/18 up/down: 44/-702)         Total: -658 bytes

1 files changed, 20 insertions, 23 deletions

diff --git a/networking/ip.c b/networking/ip.c
index fdd8480..d516895 100644
--- a/networking/ip.c
+++ b/networking/ip.c
@@ -20,31 +20,28 @@
 int ip_main(int argc, char **argv);
 int ip_main(int argc, char **argv)
 {
-	int ret = EXIT_FAILURE;
-
 	ip_parse_common_args(&argc, &argv);
 
-	if (argc > 1) {
-		if (ENABLE_FEATURE_IP_ADDRESS && matches(argv[1], "address") == 0) {
-			ret = do_ipaddr(argc-2, argv+2);
-		}
-		if (ENABLE_FEATURE_IP_ROUTE && matches(argv[1], "route") == 0) {
-			ret = do_iproute(argc-2, argv+2);
-		}
-		if (ENABLE_FEATURE_IP_LINK && matches(argv[1], "link") == 0) {
-			ret = do_iplink(argc-2, argv+2);
-		}
-		if (ENABLE_FEATURE_IP_TUNNEL
-		 && (matches(argv[1], "tunnel") == 0 || strcmp(argv[1], "tunl") == 0)
-		) {
-			ret = do_iptunnel(argc-2, argv+2);
-		}
-		if (ENABLE_FEATURE_IP_RULE && matches(argv[1], "rule") == 0) {
-			ret = do_iprule(argc-2, argv+2);
-		}
-	}
-	if (ret) {
+	if (argc <= 1)
 		bb_show_usage();
+
+	if (ENABLE_FEATURE_IP_ADDRESS && matches(argv[1], "address") == 0) {
+		return do_ipaddr(argc-2, argv+2);
+	}
+	if (ENABLE_FEATURE_IP_ROUTE && matches(argv[1], "route") == 0) {
+		return do_iproute(argc-2, argv+2);
 	}
-	return EXIT_SUCCESS;
+	if (ENABLE_FEATURE_IP_LINK && matches(argv[1], "link") == 0) {
+		return do_iplink(argc-2, argv+2);
+	}
+	if (ENABLE_FEATURE_IP_TUNNEL
+	 && (matches(argv[1], "tunnel") == 0 || strcmp(argv[1], "tunl") == 0)
+	) {
+		return do_iptunnel(argc-2, argv+2);
+	}
+	if (ENABLE_FEATURE_IP_RULE && matches(argv[1], "rule") == 0) {
+		return do_iprule(argc-2, argv+2);
+	}
+
+	bb_show_usage();
 }