arping: fix a bug where there is implicit count of 4G;

eliminate data/bss usage; code shrink

function                                             old     new   delta
timeout_us                                             4       -      -4
static.start                                           4       -      -4
src                                                    4       -      -4
sock                                                   4       -      -4
sent                                                   4       -      -4
req_recv                                               4       -      -4
received                                               4       -      -4
last                                                   4       -      -4
dst                                                    4       -      -4
count                                                  4       -      -4
brd_sent                                               4       -      -4
brd_recv                                               4       -      -4
catcher                                              375     365     -10
me                                                    20       -     -20
he                                                    20       -     -20
arping_main                                         1941    1874     -67
------------------------------------------------------------------------------
(add/remove: 0/14 grow/shrink: 0/2 up/down: 0/-165)          Total: -165 bytes
   text    data     bss     dec     hex filename
 783035     941    9244  793220   c1a84 busybox_old
 782907     937    9156  793000   c19a8 busybox_unstripped

1 files changed, 54 insertions, 32 deletions

diff --git a/networking/arping.c b/networking/arping.c
index 44615d5b1..771c3bccd 100644
--- a/networking/arping.c
+++ b/networking/arping.c
@@ -18,12 +18,6 @@
 /* We don't expect to see 1000+ seconds delay, unsigned is enough */
 #define MONOTONIC_US() ((unsigned)monotonic_us())
 
-static struct in_addr src;
-static struct in_addr dst;
-static struct sockaddr_ll me;
-static struct sockaddr_ll he;
-static unsigned last;
-
 enum {
         DAD = 1,
         UNSOLICITED = 2,
@@ -34,14 +28,43 @@ enum {
         UNICASTING = 64
 };
 
-static int sock;
-static unsigned count = UINT_MAX;
-static unsigned timeout_us;
-static unsigned sent;
-static unsigned brd_sent;
-static unsigned received;
-static unsigned brd_recv;
-static unsigned req_recv;
+struct globals {
+        struct in_addr src;
+        struct in_addr dst;
+        struct sockaddr_ll me;
+        struct sockaddr_ll he;
+        int sock;
+
+        int count; // = -1;
+        unsigned last;
+        unsigned timeout_us;
+        unsigned start;
+
+        unsigned sent;
+        unsigned brd_sent;
+        unsigned received;
+        unsigned brd_recv;
+        unsigned req_recv;
+};
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define src        (G.src       )
+#define dst        (G.dst       )
+#define me         (G.me        )
+#define he         (G.he        )
+#define sock       (G.sock      )
+#define count      (G.count     )
+#define last       (G.last      )
+#define timeout_us (G.timeout_us)
+#define start      (G.start     )
+#define sent       (G.sent      )
+#define brd_sent   (G.brd_sent  )
+#define received   (G.received  )
+#define brd_recv   (G.brd_recv  )
+#define req_recv   (G.req_recv  )
+#define INIT_G() \
+        do { \
+                count = -1; \
+        } while (0)
 
 static int send_pack(struct in_addr *src_addr,
                         struct in_addr *dst_addr, struct sockaddr_ll *ME,
@@ -106,8 +129,6 @@ static void finish(void)
 
 static void catcher(void)
 {
-        static unsigned start;
-
         unsigned now;
 
         now = MONOTONIC_US();
@@ -117,7 +138,9 @@ static void catcher(void)
         if (count == 0 || (timeout_us && (now - start) > (timeout_us + 500000)))
                 finish();
 
-        count--;
+        /* count < 0 means "infinite count" */
+        if (count > 0)
+                count--;
 
         if (last == 0 || (now - last) > 500000) {
                 send_pack(&src, &dst, &me, &he);
@@ -236,6 +259,8 @@ int arping_main(int argc, char **argv)
         char *target;
         unsigned char *packet;
 
+        INIT_G();
+
         sock = xsocket(PF_PACKET, SOCK_DGRAM, 0);
 
         // Drop suid root privileges
@@ -252,14 +277,9 @@ int arping_main(int argc, char **argv)
                 opt = getopt32(argv, "DUAqfbc:w:I:s:",
                                 &str_count, &str_timeout, &device, &source);
                 if (opt & 0x40) /* -c: count */
-                        count = xatou(str_count);
+                        count = xatoi_u(str_count);
                 if (opt & 0x80) /* -w: timeout */
                         timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000;
-                //if (opt & 0x100) /* -I: interface */
-                if (strlen(device) >= IF_NAMESIZE) {
-                        bb_error_msg_and_die("interface name '%s' is too long",
-                                                        device);
-                }
                 //if (opt & 0x200) /* -s: source */
                 option_mask32 &= 0x3f; /* set respective flags */
         }
@@ -272,8 +292,10 @@ int arping_main(int argc, char **argv)
                 struct ifreq ifr;
 
                 memset(&ifr, 0, sizeof(ifr));
-                strncpy(ifr.ifr_name, device, IFNAMSIZ - 1);
-                ioctl_or_perror_and_die(sock, SIOCGIFINDEX, &ifr, "interface %s not found", device);
+                strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name) - 1);
+                /* We use ifr.ifr_name in error msg so that problem
+                 * with truncated name will be visible */
+                ioctl_or_perror_and_die(sock, SIOCGIFINDEX, &ifr, "interface %s not found", ifr.ifr_name);
                 ifindex = ifr.ifr_ifindex;
 
                 xioctl(sock, SIOCGIFFLAGS, (char *) &ifr);
@@ -308,7 +330,7 @@ int arping_main(int argc, char **argv)
 
                 if (device) {
                         if (setsockopt(probe_fd, SOL_SOCKET, SO_BINDTODEVICE, device, strlen(device) + 1) == -1)
-                                bb_error_msg("warning: interface %s is ignored", device);
+                                bb_perror_msg("cannot bind to device %s", device);
                 }
                 memset(&saddr, 0, sizeof(saddr));
                 saddr.sin_family = AF_INET;
@@ -322,7 +344,7 @@ int arping_main(int argc, char **argv)
                         saddr.sin_addr = dst;
 
                         if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, &const_int_1, sizeof(const_int_1)) == -1)
-                                bb_perror_msg("warning: setsockopt(SO_DONTROUTE)");
+                                bb_perror_msg("setsockopt(SO_DONTROUTE)");
                         xconnect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
                         if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1) {
                                 bb_error_msg_and_die("getsockname");
@@ -345,22 +367,22 @@ int arping_main(int argc, char **argv)
                 }
         }
         if (me.sll_halen == 0) {
-                bb_error_msg("interface \"%s\" is not ARPable (no ll address)", device);
+                bb_error_msg("interface %s is not ARPable (no ll address)", device);
                 return (option_mask32 & DAD ? 0 : 2);
         }
         he = me;
         memset(he.sll_addr, -1, he.sll_halen);
 
+        if (!src.s_addr && !(option_mask32 & DAD)) {
+                bb_error_msg_and_die("no src address in the non-DAD mode");
+        }
+
         if (!(option_mask32 & QUIET)) {
                 printf("ARPING to %s from %s via %s\n",
                         inet_ntoa(dst), inet_ntoa(src),
                         device ? device : "unknown");
         }
 
-        if (!src.s_addr && !(option_mask32 & DAD)) {
-                bb_error_msg_and_die("no src address in the non-DAD mode");
-        }
-
         {
                 struct sigaction sa;