/* Display the contents of the ARP cache in the kernel. */
static int arp_show(char *name)
{
char host[100];
struct sockaddr_storage ss;
char ip[100];
char hwa[100];
char mask[100];
char line[200];
char dev[100];
int type, flags;
FILE *fp;
const char *hostname;
int num, entries = 0, showed = 0;
host[0] = '\0';
if (name != NULL) {
/* Resolve the host name. */
safe_strncpy(host, name, (sizeof host));
if (ap->input(0, host, &ss) < 0) {
ap->herror(host);
return (-1);
}
safe_strncpy(host, ap->sprint(&ss, 1), sizeof(host));
}
/* Open the PROCps kernel table. */
if ((fp = fopen(_PATH_PROCNET_ARP, "r")) == NULL) {
perror(_PATH_PROCNET_ARP);
return (-1);
}
/* Bypass header -- read until newline */
if (fgets(line, sizeof(line), fp) != (char *) NULL) {
safe_strncpy(mask, "-", sizeof(mask));
safe_strncpy(dev, "-", sizeof(dev));
/* Read the ARP cache entries. */
for (; fgets(line, sizeof(line), fp);) {
num = sscanf(line, "%s 0x%x 0x%x %99s %99s %99s\n",
ip, &type, &flags, hwa, mask, dev);
if (num < 4)
break;
entries++;
/* if the user specified hw-type differs, skip it */
if (hw_set && (type != hw->type))
continue;
/* if the user specified address differs, skip it */
if (host[0] && strcmp(ip, host))
continue;
/* if the user specified device differs, skip it */
if (device[0] && strcmp(dev, device))
continue;
showed++;
/* This IS ugly but it works -be */
if (opt_n)
hostname = "?";
else {
if (ap->input(0, ip, &ss) < 0)
hostname = ip;
else
hostname = ap->sprint(&ss, opt_n | 0x8000);
if (strcmp(hostname, ip) == 0)
hostname = "?";
}
if (opt_e)
arp_disp_2(hostname[0] == '?' ? ip : hostname, type, flags, hwa, mask, dev);
else
arp_disp(hostname, ip, type, flags, hwa, mask, dev);
}
}
if (opt_v)
printf(_("Entries: %d\tSkipped: %d\tFound: %d\n"), entries, entries - showed, showed);
if (!showed) {
if (host[0] && !opt_a)
printf(_("%s (%s) -- no entry\n"), name, host);
else if (hw_set || host[0] || device[0]) {
printf(_("arp: in %d entries no match found.\n"), entries);
}
}
(void) fclose(fp);
return (0);
}
/* Called only from main, once */
static int arp_show(char *name)
{
const char *host;
const char *hostname;
FILE *fp;
struct sockaddr sa;
int type, flags;
int num;
unsigned entries = 0, shown = 0;
char ip[128];
char hwa[128];
char mask[128];
char line[128];
char dev[128];
host = NULL;
if (name != NULL) {
/* Resolve the host name. */
if (ap->input(name, &sa) < 0) {
bb_herror_msg_and_die("%s", name);
}
host = xstrdup(ap->sprint(&sa, 1));
}
fp = xfopen("/proc/net/arp", "r");
/* Bypass header -- read one line */
fgets(line, sizeof(line), fp);
/* Read the ARP cache entries. */
while (fgets(line, sizeof(line), fp)) {
mask[0] = '-'; mask[1] = '\0';
dev[0] = '-'; dev[1] = '\0';
/* All these strings can't overflow
* because fgets above reads limited amount of data */
num = sscanf(line, "%s 0x%x 0x%x %s %s %s\n",
ip, &type, &flags, hwa, mask, dev);
if (num < 4)
break;
entries++;
/* if the user specified hw-type differs, skip it */
if (hw_set && (type != hw->type))
continue;
/* if the user specified address differs, skip it */
if (host && strcmp(ip, host) != 0)
continue;
/* if the user specified device differs, skip it */
if (device[0] && strcmp(dev, device) != 0)
continue;
shown++;
/* This IS ugly but it works -be */
hostname = "?";
if (!(option_mask32 & ARP_OPT_n)) {
if (ap->input(ip, &sa) < 0)
hostname = ip;
else
hostname = ap->sprint(&sa, (option_mask32 & ARP_OPT_n) | 0x8000);
if (strcmp(hostname, ip) == 0)
hostname = "?";
}
arp_disp(hostname, ip, type, flags, hwa, mask, dev);
}
if (option_mask32 & ARP_OPT_v)
printf("Entries: %d\tSkipped: %d\tFound: %d\n",
entries, entries - shown, shown);
if (!shown) {
if (hw_set || host || device[0])
printf("No match found in %d entries\n", entries);
}
if (ENABLE_FEATURE_CLEAN_UP) {
free((char*)host);
fclose(fp);
}
return 0;
}
