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arping: move packet buffer, sigset and struct ifreq to malloced "globals"

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This way, we can zero them all in one go.
We do malloc() anyway, thus nothing is lost by mallocing "globals"

function                                             old     new   delta
arping_main                                         1683    1686      +3
finish                                               100      86     -14
catcher                                              350     310     -40
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/2 up/down: 3/-54)             Total: -51 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-02-11 14:35:05 +01:00
parent e015d0659f
commit d3162773d5
1 changed files with 34 additions and 41 deletions
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75
networking/arping.c
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@ -79,8 +79,11 @@ struct globals {
unsigned received;
unsigned brd_recv;
unsigned req_recv;
struct ifreq ifr;
sigset_t sset;
unsigned char packet[4096];
} FIX_ALIASING;
#define G (*(struct globals*)bb_common_bufsiz1)
#define src (G.src )
#define dst (G.dst )
#define me (G.me )
@ -95,8 +98,11 @@ struct globals {
#define received (G.received )
#define brd_recv (G.brd_recv )
#define req_recv (G.req_recv )
//#define G (*(struct globals*)bb_common_bufsiz1)
#define G (*ptr_to_globals)
#define INIT_G() do { \
setup_common_bufsiz(); \
/*setup_common_bufsiz();*/ \
SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
count = -1; \
} while (0)
@ -183,15 +189,10 @@ static void recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
struct arphdr *ah = (struct arphdr *) buf;
unsigned char *p = (unsigned char *) (ah + 1);
struct in_addr src_ip, dst_ip;
/* moves below assume in_addr is 4 bytes big, ensure that */
struct BUG_in_addr_must_be_4 {
char BUG_in_addr_must_be_4[
sizeof(struct in_addr) == 4 ? 1 : -1
];
char BUG_s_addr_must_be_4[
sizeof(src_ip.s_addr) == 4 ? 1 : -1
];
};
BUILD_BUG_ON(sizeof(struct in_addr) != 4);
BUILD_BUG_ON(sizeof(src_ip.s_addr) != 4);
/* Filter out wild packets */
if (FROM->sll_pkttype != PACKET_HOST
@ -212,8 +213,10 @@ static void recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
if (ah->ar_pro != htons(ETH_P_IP)
|| (ah->ar_pln != 4)
|| (ah->ar_hln != me.sll_halen)
|| (len < (int)(sizeof(*ah) + 2 * (4 + ah->ar_hln))))
|| (len < (int)(sizeof(*ah) + 2 * (4 + ah->ar_hln)))
) {
return;
}
move_from_unaligned32(src_ip.s_addr, p + ah->ar_hln);
move_from_unaligned32(dst_ip.s_addr, p + ah->ar_hln + 4 + ah->ar_hln);
@ -292,7 +295,6 @@ int arping_main(int argc UNUSED_PARAM, char **argv)
const char *device = "eth0";
char *source = NULL;
char *target;
unsigned char *packet;
char *err_str;
INIT_G();
@ -316,27 +318,21 @@ int arping_main(int argc UNUSED_PARAM, char **argv)
err_str = xasprintf("interface %s %%s", device);
xfunc_error_retval = 2;
{
struct ifreq ifr;
/*memset(&G.ifr, 0, sizeof(G.ifr)); - zeroed by INIT_G */
strncpy_IFNAMSIZ(G.ifr.ifr_name, device);
ioctl_or_perror_and_die(sock_fd, SIOCGIFINDEX, &G.ifr, err_str, "not found");
me.sll_ifindex = G.ifr.ifr_ifindex;
memset(&ifr, 0, sizeof(ifr));
strncpy_IFNAMSIZ(ifr.ifr_name, device);
/* We use ifr.ifr_name in error msg so that problem
* with truncated name will be visible */
ioctl_or_perror_and_die(sock_fd, SIOCGIFINDEX, &ifr, err_str, "not found");
me.sll_ifindex = ifr.ifr_ifindex;
xioctl(sock_fd, SIOCGIFFLAGS, (char *) &G.ifr);
xioctl(sock_fd, SIOCGIFFLAGS, (char *) &ifr);
if (!(ifr.ifr_flags & IFF_UP)) {
bb_error_msg_and_die(err_str, "is down");
}
if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
bb_error_msg(err_str, "is not ARPable");
BUILD_BUG_ON(DAD != 2);
/* exit 0 if DAD, else exit 2 */
return (~option_mask32 & DAD);
}
if (!(G.ifr.ifr_flags & IFF_UP)) {
bb_error_msg_and_die(err_str, "is down");
}
if (G.ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
bb_error_msg(err_str, "is not ARPable");
BUILD_BUG_ON(DAD != 2);
/* exit 0 if DAD, else exit 2 */
return (~option_mask32 & DAD);
}
/* if (!inet_aton(target, &dst)) - not needed */ {
@ -413,8 +409,9 @@ int arping_main(int argc UNUSED_PARAM, char **argv)
printf(" from %s %s\n", inet_ntoa(src), device);
}
packet = xmalloc(4096);
/*sigemptyset(&G.sset); - zeroed by INIT_G */
sigaddset(&G.sset, SIGALRM);
sigaddset(&G.sset, SIGINT);
signal_SA_RESTART_empty_mask(SIGINT, (void (*)(int))finish);
signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher);
@ -422,28 +419,24 @@ int arping_main(int argc UNUSED_PARAM, char **argv)
catcher();
while (1) {
sigset_t sset;
struct sockaddr_ll from;
socklen_t alen = sizeof(from);
int cc;
sigemptyset(&sset);
sigaddset(&sset, SIGALRM);
sigaddset(&sset, SIGINT);
/* Unblock SIGALRM so that the previously called alarm()
* can prevent recvfrom from blocking forever in case the
* inherited procmask is blocking SIGALRM.
*/
sigprocmask(SIG_UNBLOCK, &sset, NULL);
sigprocmask(SIG_UNBLOCK, &G.sset, NULL);
cc = recvfrom(sock_fd, packet, 4096, 0, (struct sockaddr *) &from, &alen);
cc = recvfrom(sock_fd, G.packet, sizeof(G.packet), 0, (struct sockaddr *) &from, &alen);
/* Don't allow SIGALRMs while we process the reply */
sigprocmask(SIG_BLOCK, &sset, NULL);
sigprocmask(SIG_BLOCK, &G.sset, NULL);
if (cc < 0) {
bb_perror_msg("recvfrom");
continue;
}
recv_pack(packet, cc, &from);
recv_pack(G.packet, cc, &from);
}
}