arping: code shrink

Do not clear extra bits on option_mask32, it's not necessary.
Move DAD bit to 2, this makes exit logic simpler.

function                                             old     new   delta
arping_main                                         1655    1629     -26

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/networking/arping.c b/networking/arping.c
index f9967d81e5b2b99b9559d08872c7189c4895ad61..fd2f52cdb518ed396bed70d106b82d84fa7fa084 100644 (file)
--- a/networking/arping.c
+++ b/networking/arping.c
@@ -11,7 +11,6 @@
 //config:      select PLATFORM_LINUX
 //config:      help
 //config:      Ping hosts by ARP packets.
-//config:
 
 //applet:IF_ARPING(APPLET(arping, BB_DIR_USR_SBIN, BB_SUID_DROP))
 
@@ -45,14 +44,23 @@
 #define MONOTONIC_US() ((unsigned)monotonic_us())
 
 enum {
-       DAD = 1,
-       UNSOLICITED = 2,
-       ADVERT = 4,
-       QUIET = 8,
-       QUIT_ON_REPLY = 16,
-       BCAST_ONLY = 32,
-       UNICASTING = 64
+       UNSOLICITED   = 1 << 0,
+       DAD           = 1 << 1,
+       ADVERT        = 1 << 2,
+       QUIET         = 1 << 3,
+       QUIT_ON_REPLY = 1 << 4,
+       BCAST_ONLY    = 1 << 5,
+       UNICASTING    = 1 << 6,
+       TIMEOUT       = 1 << 7,
 };
+#define GETOPT32(str_timeout, device, source) \
+       getopt32(argv, "^" \
+               "UDAqfbc:+w:I:s:" \
+               /* Dad also sets quit_on_reply, */ \
+               /* Advert also sets unsolicited: */ \
+               "\0" "=1:Df:AU", \
+               &count, &str_timeout, &device, &source \
+       );
 
 struct globals {
        struct in_addr src;
@@ -92,21 +100,15 @@ struct globals {
        count = -1; \
 } while (0)
 
-// If GNUisms are not available...
-//static void *mempcpy(void *_dst, const void *_src, int n)
-//{
-//     memcpy(_dst, _src, n);
-//     return (char*)_dst + n;
-//}
-
 static int send_pack(struct in_addr *src_addr,
-                       struct in_addr *dst_addr, struct sockaddr_ll *ME,
+                       struct in_addr *dst_addr,
+                       struct sockaddr_ll *ME,
                        struct sockaddr_ll *HE)
 {
        int err;
        unsigned char buf[256];
        struct arphdr *ah = (struct arphdr *) buf;
-       unsigned char *p = (unsigned char *) (ah + 1);
+       unsigned char *p;
 
        ah->ar_hrd = htons(ARPHRD_ETHER);
        ah->ar_pro = htons(ETH_P_IP);
@@ -114,6 +116,7 @@ static int send_pack(struct in_addr *src_addr,
        ah->ar_pln = 4;
        ah->ar_op = option_mask32 & ADVERT ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
 
+       p = (unsigned char *) (ah + 1);
        p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
        p = mempcpy(p, src_addr, 4);
 
@@ -303,16 +306,9 @@ int arping_main(int argc UNUSED_PARAM, char **argv)
                unsigned opt;
                char *str_timeout;
 
-               /* Dad also sets quit_on_reply.
-                * Advert also sets unsolicited.
-                */
-               opt = getopt32(argv, "^" "DUAqfbc:+w:I:s:" "\0" "=1:Df:AU",
-                               &count, &str_timeout, &device, &source
-               );
-               if (opt & 0x80) /* -w: timeout */
+               opt = GETOPT32(str_timeout, device, source);
+               if (opt & TIMEOUT)
                        timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000 + 500000;
-               //if (opt & 0x200) /* -s: source */
-               option_mask32 &= 0x3f; /* set respective flags */
        }
 
        target = argv[optind];
@@ -336,7 +332,9 @@ int arping_main(int argc UNUSED_PARAM, char **argv)
                }
                if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
                        bb_error_msg(err_str, "is not ARPable");
-                       return (option_mask32 & DAD ? 0 : 2);
+                       BUILD_BUG_ON(DAD != 2);
+                       /* exit 0 if DAD, else exit 2 */
+                       return (~option_mask32 & DAD);
                }
        }
 
@@ -401,7 +399,9 @@ int arping_main(int argc UNUSED_PARAM, char **argv)
        }
        if (me.sll_halen == 0) {
                bb_error_msg(err_str, "is not ARPable (no ll address)");
-               return (option_mask32 & DAD ? 0 : 2);
+               BUILD_BUG_ON(DAD != 2);
+               /* exit 0 if DAD, else exit 2 */
+               return (~option_mask32 & DAD);
        }
        he = me;
        memset(he.sll_addr, -1, he.sll_halen);