ping utility ripped off from busybox rev 1.22.0, turned into a standalone program + added SOCK_DGRAM functionality for root-free ping and ping6. [ http://lists.busybox.net/pipermail/busybox/2014-January/080206.html rejected SOCK_DGRAM patch as taken from busybox ml]

bb-ping.c

/* vi: set sw=4 ts=4: */
/*
 * Mini ping implementation for busybox
 *
 * Copyright (C) 1999 by Randolph Chung <[email protected]>
 *
 * Adapted from the ping in netkit-base 0.10:
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Mike Muuss.
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
/* from ping6.c:
 * Copyright (C) 1999 by Randolph Chung <[email protected]>
 *
 * This version of ping is adapted from the ping in netkit-base 0.10,
 * which is:
 *
 * Original copyright notice is retained at the end of this file.
 *
 * This version is an adaptation of ping.c from busybox.
 * The code was modified by Bart Visscher <[email protected]>
 */

#include <time.h>
#include <stdarg.h>
#include <unistd.h>
#include <limits.h>
#include <net/if.h>
#include <netinet/ip_icmp.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <signal.h>
#include <stddef.h>
#include <netinet/icmp6.h>
#include <netdb.h>
#include <stdint.h>
#include <endian.h>
#include <ctype.h>
#include <fcntl.h>
#include <arpa/inet.h>
#include <syscall.h>

#if (__BYTE_ORDER == __BIG_ENDIAN) || (__BYTE_ORDER__ == __BIG_ENDIAN__)
#define BB_LITTLE_ENDIAN 0
#else
#define BB_LITTLE_ENDIAN 1
#endif

#define FAST_FUNC
#define ENABLE_PING6 1
#define ENABLE_FEATURE_IPV6 1
#define ENABLE_FEATURE_CLEAN_UP 1
#define ENABLE_FEATURE_FANCY_PING 1
#define IF_PING6(X) X
#define NORETURN
#define UNUSED_PARAM
#define EXIT_FAILURE 1
#define EXIT_SUCCESS 0
#define ENABLE_FEATURE_PREFER_IPV4_ADDRESS 1
#define ENABLE_FEATURE_UNIX_LOCAL 0
#define MAIN_EXTERNALLY_VISIBLE
#define ALIGNED(X) __attribute__((aligned(X)))
#define bb_msg_can_not_create_raw_socket "can't create raw socket"
#define bb_msg_perm_denied_are_you_root "permission denied (are you root?)"
#define bb_msg_memory_exhausted "out of memory"
#define bb_msg_write_error "write error"
#define bb_perror_msg(...) do { dprintf(2, __VA_ARGS__); perror(""); } while(0)
#define bb_error_msg(...) dprintf(2, __VA_ARGS__)
#define move_from_unaligned_int(v, intp) (memcpy(&(v), (intp), sizeof(int)))

#define bb__aliased_uint32_t uint32_t
typedef signed char smallint;

const int const_int_1 = 1;

void FAST_FUNC xfunc_die(void){ exit(1); }
void bb_show_usage(void) { printf("usage:\n"); exit(1); }
void bb_perror_msg_and_die(const char *s)  { perror(s); exit(1); }
#define bb_error_msg_and_die(...) do { dprintf(2, __VA_ARGS__); exit(1); } while(0)

/* libc has incredibly messy way of doing this,
 * typically requiring -lrt. We just skip all this mess */
static void get_mono(struct timespec *ts)
{
	if (syscall(__NR_clock_gettime, CLOCK_MONOTONIC, ts))
		bb_error_msg_and_die("clock_gettime(MONOTONIC) failed");
}

unsigned long long FAST_FUNC monotonic_us(void)
{
	struct timespec ts;
	get_mono(&ts);
	return ts.tv_sec * 1000000ULL + ts.tv_nsec/1000;
}




int FAST_FUNC fflush_all(void)
{
	return fflush(NULL);
}

void FAST_FUNC xbind(int sockfd, struct sockaddr *my_addr, socklen_t addrlen)
{
	if (bind(sockfd, my_addr, addrlen)) bb_perror_msg_and_die("bind");
}


static unsigned long long ret_ERANGE(void)
{
	errno = ERANGE; /* this ain't as small as it looks (on glibc) */
	return ULLONG_MAX;
}

static unsigned long long handle_errors(unsigned long long v, char **endp)
{
	char next_ch = **endp;

	/* errno is already set to ERANGE by strtoXXX if value overflowed */
	if (next_ch) {
		/* "1234abcg" or out-of-range? */
		if (isalnum(next_ch) || errno)
			return ret_ERANGE();
		/* good number, just suspicious terminator */
		errno = EINVAL;
	}
	return v;
}

unsigned FAST_FUNC bb_strtou(const char *arg, char **endp, int base)
{
	unsigned long v;
	char *endptr;

	if (!endp) endp = &endptr;
	*endp = (char*) arg;

	/* strtoul("  -4200000000") returns 94967296, errno 0 (!) */
	/* I don't think that this is right. Preventing this... */
	if (!isalnum(arg[0])) return ret_ERANGE();

	/* not 100% correct for lib func, but convenient for the caller */
	errno = 0;
	v = strtoul(arg, endp, base);
	if (v > UINT_MAX) return ret_ERANGE();
	return handle_errors(v, endp);
}

void FAST_FUNC set_nport(struct sockaddr *sa, unsigned port)
{
#if ENABLE_FEATURE_IPV6
	if (sa->sa_family == AF_INET6) {
		struct sockaddr_in6 *sin6 = (void*) sa;
		sin6->sin6_port = port;
		return;
	}
#endif
	if (sa->sa_family == AF_INET) {
		struct sockaddr_in *sin = (void*) sa;
		sin->sin_port = port;
		return;
	}
	/* What? UNIX socket? IPX?? :) */
}

/* Like strncpy but make sure the resulting string is always 0 terminated. */
char* FAST_FUNC safe_strncpy(char *dst, const char *src, size_t size)
{
	if (!size) return dst;
	dst[--size] = '\0';
	return strncpy(dst, src, size);
}

char* FAST_FUNC strncpy_IFNAMSIZ(char *dst, const char *src)
{
#ifndef IFNAMSIZ
	enum { IFNAMSIZ = 16 };
#endif
	return strncpy(dst, src, IFNAMSIZ);
}

// Die if we can't allocate size bytes of memory.
void* FAST_FUNC xmalloc(size_t size)
{
	void *ptr = malloc(size);
	if (ptr == NULL && size != 0)
		bb_error_msg_and_die(bb_msg_memory_exhausted);
	return ptr;
}

// Die if we can't allocate and zero size bytes of memory.
void* FAST_FUNC xzalloc(size_t size)
{
	void *ptr = xmalloc(size);
	memset(ptr, 0, size);
	return ptr;
}

enum {
	PARAM_STRING,
	PARAM_LIST,
	PARAM_INT,
};

typedef struct llist_t {
        struct llist_t *link;
        char *data;
} llist_t;

/* Add data to the end of the linked list.  */
void FAST_FUNC llist_add_to_end(llist_t **list_head, void *data)
{
	while (*list_head)
		list_head = &(*list_head)->link;
	*list_head = xzalloc(sizeof(llist_t));
	(*list_head)->data = data;
	/*(*list_head)->link = NULL;*/
}

int FAST_FUNC setsockopt_broadcast(int fd)
{
	return setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &const_int_1, sizeof(const_int_1));
}

#ifdef SO_BINDTODEVICE
int FAST_FUNC setsockopt_bindtodevice(int fd, const char *iface)
{
	int r;
	struct ifreq ifr;
	strncpy_IFNAMSIZ(ifr.ifr_name, iface);
	/* NB: passing (iface, strlen(iface) + 1) does not work!
	 * (maybe it works on _some_ kernels, but not on 2.6.26)
	 * Actually, ifr_name is at offset 0, and in practice
	 * just giving char[IFNAMSIZ] instead of struct ifreq works too.
	 * But just in case it's not true on some obscure arch... */
	r = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
	if (r)
		bb_perror_msg("can't bind to interface %s", iface);
	return r;
}
#else
int FAST_FUNC setsockopt_bindtodevice(int fd UNUSED_PARAM,
		const char *iface UNUSED_PARAM)
{
	bb_error_msg("SO_BINDTODEVICE is not supported on this system");
	return -1;
}
#endif


typedef struct {
	unsigned char opt_char;
	smallint param_type;
	unsigned switch_on;
	unsigned switch_off;
	unsigned incongruously;
	unsigned requires;
	void **optarg;  /* char**, llist_t** or int *. */
	int *counter;
} t_complementary;

const char* opt_complementary;
uint32_t option_mask32;
int xatoi_positive(const char *);

uint32_t FAST_FUNC
getopt32(char **argv, const char *applet_opts, ...)
{
	int argc;
	unsigned flags = 0;
	unsigned requires = 0;
	t_complementary complementary[33]; /* last stays zero-filled */
	char first_char;
	int c;
	const unsigned char *s;
	t_complementary *on_off;
	va_list p;
#if ENABLE_LONG_OPTS || ENABLE_FEATURE_GETOPT_LONG
	const struct option *l_o;
	struct option *long_options = (struct option *) &bb_null_long_options;
#endif
	unsigned trigger;
	char **pargv;
	int min_arg = 0;
	int max_arg = -1;

#define SHOW_USAGE_IF_ERROR     1
#define ALL_ARGV_IS_OPTS        2
#define FIRST_ARGV_IS_OPT       4

	int spec_flgs = 0;

	/* skip 0: some applets cheat: they do not actually HAVE argv[0] */
	argc = 1;
	while (argv[argc])
		argc++;

	va_start(p, applet_opts);

	c = 0;
	on_off = complementary;
	memset(on_off, 0, sizeof(complementary));

	/* skip bbox extension */
	first_char = applet_opts[0];
	if (first_char == '!')
		applet_opts++;

	/* skip GNU extension */
	s = (const unsigned char *)applet_opts;
	if (*s == '+' || *s == '-')
		s++;
	while (*s) {
		if (c >= 32)
			break;
		on_off->opt_char = *s;
		on_off->switch_on = (1 << c);
		if (*++s == ':') {
			on_off->optarg = va_arg(p, void **);
			while (*++s == ':')
				continue;
		}
		on_off++;
		c++;
	}

#if ENABLE_LONG_OPTS || ENABLE_FEATURE_GETOPT_LONG
	if (applet_long_options) {
		const char *optstr;
		unsigned i, count;

		count = 1;
		optstr = applet_long_options;
		while (optstr[0]) {
			optstr += strlen(optstr) + 3; /* skip NUL, has_arg, val */
			count++;
		}
		/* count == no. of longopts + 1 */
		long_options = alloca(count * sizeof(*long_options));
		memset(long_options, 0, count * sizeof(*long_options));
		i = 0;
		optstr = applet_long_options;
		while (--count) {
			long_options[i].name = optstr;
			optstr += strlen(optstr) + 1;
			long_options[i].has_arg = (unsigned char)(*optstr++);
			/* long_options[i].flag = NULL; */
			long_options[i].val = (unsigned char)(*optstr++);
			i++;
		}
		for (l_o = long_options; l_o->name; l_o++) {
			if (l_o->flag)
				continue;
			for (on_off = complementary; on_off->opt_char; on_off++)
				if (on_off->opt_char == l_o->val)
					goto next_long;
			if (c >= 32)
				break;
			on_off->opt_char = l_o->val;
			on_off->switch_on = (1 << c);
			if (l_o->has_arg != no_argument)
				on_off->optarg = va_arg(p, void **);
			c++;
 next_long: ;
		}
		/* Make it unnecessary to clear applet_long_options
		 * by hand after each call to getopt32
		 */
		applet_long_options = NULL;
	}
#endif /* ENABLE_LONG_OPTS || ENABLE_FEATURE_GETOPT_LONG */
	for (s = (const unsigned char *)opt_complementary; s && *s; s++) {
		t_complementary *pair;
		unsigned *pair_switch;

		if (*s == ':')
			continue;
		c = s[1];
		if (*s == '?') {
			if (c < '0' || c > '9') {
				spec_flgs |= SHOW_USAGE_IF_ERROR;
			} else {
				max_arg = c - '0';
				s++;
			}
			continue;
		}
		if (*s == '-') {
			if (c < '0' || c > '9') {
				if (c == '-') {
					spec_flgs |= FIRST_ARGV_IS_OPT;
					s++;
				} else
					spec_flgs |= ALL_ARGV_IS_OPTS;
			} else {
				min_arg = c - '0';
				s++;
			}
			continue;
		}
		if (*s == '=') {
			min_arg = max_arg = c - '0';
			s++;
			continue;
		}
		for (on_off = complementary; on_off->opt_char; on_off++)
			if (on_off->opt_char == *s)
				goto found_opt;
		/* Without this, diagnostic of such bugs is not easy */
		bb_error_msg_and_die("NO OPT %c!", *s);
 found_opt:
		if (c == ':' && s[2] == ':') {
			on_off->param_type = PARAM_LIST;
			continue;
		}
		if (c == '+' && (s[2] == ':' || s[2] == '\0')) {
			on_off->param_type = PARAM_INT;
			s++;
			continue;
		}
		if (c == ':' || c == '\0') {
			requires |= on_off->switch_on;
			continue;
		}
		if (c == '-' && (s[2] == ':' || s[2] == '\0')) {
			flags |= on_off->switch_on;
			on_off->incongruously |= on_off->switch_on;
			s++;
			continue;
		}
		if (c == *s) {
			on_off->counter = va_arg(p, int *);
			s++;
		}
		pair = on_off;
		pair_switch = &pair->switch_on;
		for (s++; *s && *s != ':'; s++) {
			if (*s == '?') {
				pair_switch = &pair->requires;
			} else if (*s == '-') {
				if (pair_switch == &pair->switch_off)
					pair_switch = &pair->incongruously;
				else
					pair_switch = &pair->switch_off;
			} else {
				for (on_off = complementary; on_off->opt_char; on_off++)
					if (on_off->opt_char == *s) {
						*pair_switch |= on_off->switch_on;
						break;
					}
			}
		}
		s--;
	}
	opt_complementary = NULL;
	va_end(p);

	if (spec_flgs & (FIRST_ARGV_IS_OPT | ALL_ARGV_IS_OPTS)) {
		pargv = argv + 1;
		while (*pargv) {
			if (pargv[0][0] != '-' && pargv[0][0] != '\0') {
				/* Can't use alloca: opts with params will
				 * return pointers to stack!
				 * NB: we leak these allocations... */
				char *pp = xmalloc(strlen(*pargv) + 2);
				*pp = '-';
				strcpy(pp + 1, *pargv);
				*pargv = pp;
			}
			if (!(spec_flgs & ALL_ARGV_IS_OPTS))
				break;
			pargv++;
		}
	}

	/* In case getopt32 was already called:
	 * reset the libc getopt() function, which keeps internal state.
	 * run_nofork_applet() does this, but we might end up here
	 * also via gunzip_main() -> gzip_main(). Play safe.
	 */
#ifdef __GLIBC__
	optind = 0;
#else /* BSD style */
	optind = 1;
	/* optreset = 1; */
#endif
	/* optarg = NULL; opterr = 0; optopt = 0; - do we need this?? */

	/* Note: just "getopt() <= 0" will not work well for
	 * "fake" short options, like this one:
	 * wget $'-\203' "Test: test" http://kernel.org/
	 * (supposed to act as --header, but doesn't) */
#if ENABLE_LONG_OPTS || ENABLE_FEATURE_GETOPT_LONG
	while ((c = getopt_long(argc, argv, applet_opts,
			long_options, NULL)) != -1) {
#else
	while ((c = getopt(argc, argv, applet_opts)) != -1) {
#endif
		/* getopt prints "option requires an argument -- X"
		 * and returns '?' if an option has no arg, but one is reqd */
		c &= 0xff; /* fight libc's sign extension */
		for (on_off = complementary; on_off->opt_char != c; on_off++) {
			/* c can be NUL if long opt has non-NULL ->flag,
			 * but we construct long opts so that flag
			 * is always NULL (see above) */
			if (on_off->opt_char == '\0' /* && c != '\0' */) {
				/* c is probably '?' - "bad option" */
				goto error;
			}
		}
		if (flags & on_off->incongruously)
			goto error;
		trigger = on_off->switch_on & on_off->switch_off;
		flags &= ~(on_off->switch_off ^ trigger);
		flags |= on_off->switch_on ^ trigger;
		flags ^= trigger;
		if (on_off->counter)
			(*(on_off->counter))++;
		if (optarg) {
			if (on_off->param_type == PARAM_LIST) {
				llist_add_to_end((llist_t **)(on_off->optarg), optarg);
			} else if (on_off->param_type == PARAM_INT) {
//TODO: xatoi_positive indirectly pulls in printf machinery
				*(unsigned*)(on_off->optarg) = xatoi_positive(optarg);
			} else if (on_off->optarg) {
				*(char **)(on_off->optarg) = optarg;
			}
		}
	}

	/* check depending requires for given options */
	for (on_off = complementary; on_off->opt_char; on_off++) {
		if (on_off->requires
		 && (flags & on_off->switch_on)
		 && (flags & on_off->requires) == 0
		) {
			goto error;
		}
	}
	if (requires && (flags & requires) == 0)
		goto error;
	argc -= optind;
	if (argc < min_arg || (max_arg >= 0 && argc > max_arg))
		goto error;

	option_mask32 = flags;
	return flags;

 error:
	if (first_char != '!')
		bb_show_usage();
	return (int32_t)-1;
}


enum { COMMON_BUFSIZE = (BUFSIZ >= 256*sizeof(void*) ? BUFSIZ+1 : 256*sizeof(void*)) };
char bb_common_bufsiz1[COMMON_BUFSIZE] ALIGNED(sizeof(long long));
typedef struct len_and_sockaddr {
        socklen_t len;
        union {
                struct sockaddr sa;
                struct sockaddr_in sin;
#if ENABLE_FEATURE_IPV6
                struct sockaddr_in6 sin6;
#endif
        } u;
} len_and_sockaddr;

enum {
        LSA_LEN_SIZE = offsetof(len_and_sockaddr, u),
        LSA_SIZEOF_SA = sizeof(
                union {
                        struct sockaddr sa;
                        struct sockaddr_in sin;
#if ENABLE_FEATURE_IPV6
                        struct sockaddr_in6 sin6;
#endif
                }
        )
};

/* We hijack this constant to mean something else */
/* It doesn't hurt because we will remove this bit anyway */
#define DIE_ON_ERROR AI_CANONNAME

/* host: "1.2.3.4[:port]", "www.google.com[:port]"
 * port: if neither of above specifies port # */
static len_and_sockaddr* str2sockaddr(
		const char *host, int port,
		sa_family_t af,
		int ai_flags)
{
	//IF_NOT_FEATURE_IPV6(sa_family_t af = AF_INET;)
	int rc;
	len_and_sockaddr *r;
	struct addrinfo *result = NULL;
	struct addrinfo *used_res;
	const char *org_host = host; /* only for error msg */
	const char *cp;
	struct addrinfo hint;

	if (ENABLE_FEATURE_UNIX_LOCAL && strncmp(host, "local:", 6) == 0) {
		struct sockaddr_un *sun;

		r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_un));
		r->len = sizeof(struct sockaddr_un);
		r->u.sa.sa_family = AF_UNIX;
		sun = (struct sockaddr_un *)&r->u.sa;
		safe_strncpy(sun->sun_path, host + 6, sizeof(sun->sun_path));
		return r;
	}

	r = NULL;

	/* Ugly parsing of host:addr */
	if (ENABLE_FEATURE_IPV6 && host[0] == '[') {
		/* Even uglier parsing of [xx]:nn */
		host++;
		cp = strchr(host, ']');
		if (!cp || (cp[1] != ':' && cp[1] != '\0')) {
			/* Malformed: must be [xx]:nn or [xx] */
			bb_error_msg("bad address '%s'", org_host);
			if (ai_flags & DIE_ON_ERROR)
				xfunc_die();
			return NULL;
		}
	} else {
		cp = strrchr(host, ':');
		if (ENABLE_FEATURE_IPV6 && cp && strchr(host, ':') != cp) {
			/* There is more than one ':' (e.g. "::1") */
			cp = NULL; /* it's not a port spec */
		}
	}
	if (cp) { /* points to ":" or "]:" */
		int sz = cp - host + 1;

		host = safe_strncpy(alloca(sz), host, sz);
		if (ENABLE_FEATURE_IPV6 && *cp != ':') {
			cp++; /* skip ']' */
			if (*cp == '\0') /* [xx] without port */
				goto skip;
		}
		cp++; /* skip ':' */
		port = bb_strtou(cp, NULL, 10);
		if (errno || (unsigned)port > 0xffff) {
			bb_error_msg("bad port spec '%s'", org_host);
			if (ai_flags & DIE_ON_ERROR)
				xfunc_die();
			return NULL;
		}
 skip: ;
	}

	/* Next two if blocks allow to skip getaddrinfo()
	 * in case host name is a numeric IP(v6) address.
	 * getaddrinfo() initializes DNS resolution machinery,
	 * scans network config and such - tens of syscalls.
	 */
	/* If we were not asked specifically for IPv6,
	 * check whether this is a numeric IPv4 */
	//IF_FEATURE_IPV6(if(af != AF_INET6)) {
	if(af != AF_INET6) {
		struct in_addr in4;
		if (inet_aton(host, &in4) != 0) {
			r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_in));
			r->len = sizeof(struct sockaddr_in);
			r->u.sa.sa_family = AF_INET;
			r->u.sin.sin_addr = in4;
			goto set_port;
		}
	}
#if ENABLE_FEATURE_IPV6
	/* If we were not asked specifically for IPv4,
	 * check whether this is a numeric IPv6 */
	if (af != AF_INET) {
		struct in6_addr in6;
		if (inet_pton(AF_INET6, host, &in6) > 0) {
			r = xzalloc(LSA_LEN_SIZE + sizeof(struct sockaddr_in6));
			r->len = sizeof(struct sockaddr_in6);
			r->u.sa.sa_family = AF_INET6;
			r->u.sin6.sin6_addr = in6;
			goto set_port;
		}
	}
#endif

	memset(&hint, 0 , sizeof(hint));
	hint.ai_family = af;
	/* Need SOCK_STREAM, or else we get each address thrice (or more)
	 * for each possible socket type (tcp,udp,raw...): */
	hint.ai_socktype = SOCK_STREAM;
	hint.ai_flags = ai_flags & ~DIE_ON_ERROR;
	rc = getaddrinfo(host, NULL, &hint, &result);
	if (rc || !result) {
		bb_error_msg("bad address '%s'", org_host);
		if (ai_flags & DIE_ON_ERROR)
			xfunc_die();
		goto ret;
	}
	used_res = result;
#if ENABLE_FEATURE_PREFER_IPV4_ADDRESS
	while (1) {
		if (used_res->ai_family == AF_INET)
			break;
		used_res = used_res->ai_next;
		if (!used_res) {
			used_res = result;
			break;
		}
	}
#endif
	r = xmalloc(LSA_LEN_SIZE + used_res->ai_addrlen);
	r->len = used_res->ai_addrlen;
	memcpy(&r->u.sa, used_res->ai_addr, used_res->ai_addrlen);

 set_port:
	set_nport(&r->u.sa, htons(port));
 ret:
	if (result)
		freeaddrinfo(result);
	return r;
}
#if !ENABLE_FEATURE_IPV6
#define str2sockaddr(host, port, af, ai_flags) str2sockaddr(host, port, ai_flags)
#endif

len_and_sockaddr* FAST_FUNC xdotted2sockaddr(const char *host, int port)
{
	return str2sockaddr(host, port, AF_UNSPEC, AI_NUMERICHOST | DIE_ON_ERROR);
}

len_and_sockaddr* FAST_FUNC xhost_and_af2sockaddr(const char *host, int port, sa_family_t af)
{
	return str2sockaddr(host, port, af, DIE_ON_ERROR);
}

// Die if we can't copy a string to freshly allocated memory.
char* FAST_FUNC xstrdup(const char *s)
{
	char *t;

	if (s == NULL)
		return NULL;

	t = strdup(s);

	if (t == NULL)
		bb_error_msg_and_die(bb_msg_memory_exhausted);

	return t;
}


// Die with an error message if we can't malloc() enough space and do an
// sprintf() into that space.
char* FAST_FUNC xasprintf(const char *format, ...)
{
	va_list p;
	int r;
	char *string_ptr;

	va_start(p, format);
	r = vasprintf(&string_ptr, format, p);
	va_end(p);

	if (r < 0)
		bb_error_msg_and_die(bb_msg_memory_exhausted);
	return string_ptr;
}


/* We hijack this constant to mean something else */
/* It doesn't hurt because we will add this bit anyway */
#define IGNORE_PORT NI_NUMERICSERV
static char* FAST_FUNC sockaddr2str(const struct sockaddr *sa, int flags)
{
	char host[128];
	char serv[16];
	int rc;
	socklen_t salen;

	if (ENABLE_FEATURE_UNIX_LOCAL && sa->sa_family == AF_UNIX) {
		struct sockaddr_un *sun = (struct sockaddr_un *)sa;
		return xasprintf("local:%.*s",
				(int) sizeof(sun->sun_path),
				sun->sun_path);
	}

	salen = LSA_SIZEOF_SA;
#if ENABLE_FEATURE_IPV6
	if (sa->sa_family == AF_INET)
		salen = sizeof(struct sockaddr_in);
	if (sa->sa_family == AF_INET6)
		salen = sizeof(struct sockaddr_in6);
#endif
	rc = getnameinfo(sa, salen,
			host, sizeof(host),
	/* can do ((flags & IGNORE_PORT) ? NULL : serv) but why bother? */
			serv, sizeof(serv),
			/* do not resolve port# into service _name_ */
			flags | NI_NUMERICSERV
	);
	if (rc)
		return NULL;
	if (flags & IGNORE_PORT)
		return xstrdup(host);
#if ENABLE_FEATURE_IPV6
	if (sa->sa_family == AF_INET6) {
		if (strchr(host, ':')) /* heh, it's not a resolved hostname */
			return xasprintf("[%s]:%s", host, serv);
		/*return xasprintf("%s:%s", host, serv);*/
		/* - fall through instead */
	}
#endif
	/* For now we don't support anything else, so it has to be INET */
	/*if (sa->sa_family == AF_INET)*/
		return xasprintf("%s:%s", host, serv);
	/*return xstrdup(host);*/
}



char* FAST_FUNC xmalloc_sockaddr2dotted_noport(const struct sockaddr *sa)
{
	return sockaddr2str(sa, NI_NUMERICHOST | IGNORE_PORT);
}

/* Die with an error message if sendto failed.
 * Return bytes sent otherwise  */
ssize_t FAST_FUNC xsendto(int s, const void *buf, size_t len, const struct sockaddr *to,
				socklen_t tolen)
{
	ssize_t ret = sendto(s, buf, len, 0, to, tolen);
	if (ret < 0) {
		if (ENABLE_FEATURE_CLEAN_UP)
			close(s);
		bb_perror_msg_and_die("sendto");
	}
	return ret;
}


void FAST_FUNC xdup2(int from, int to)
{
	if (dup2(from, to) != to)
		bb_perror_msg_and_die("can't duplicate file descriptor");
}


// "Renumber" opened fd
void FAST_FUNC xmove_fd(int from, int to)
{
	if (from == to)
		return;
	xdup2(from, to);
	close(from);
}

uint16_t FAST_FUNC inet_cksum(uint16_t *addr, int nleft)
{
	/*
	 * Our algorithm is simple, using a 32 bit accumulator,
	 * we add sequential 16 bit words to it, and at the end, fold
	 * back all the carry bits from the top 16 bits into the lower
	 * 16 bits.
	 */
	unsigned sum = 0;
	while (nleft > 1) {
		sum += *addr++;
		nleft -= 2;
	}

	/* Mop up an odd byte, if necessary */
	if (nleft == 1) {
		if (BB_LITTLE_ENDIAN)
			sum += *(uint8_t*)addr;
		else
			sum += *(uint8_t*)addr << 8;
	}

	/* Add back carry outs from top 16 bits to low 16 bits */
	sum = (sum >> 16) + (sum & 0xffff);     /* add hi 16 to low 16 */
	sum += (sum >> 16);                     /* add carry */

	return (uint16_t)~sum;
}
struct suffix_mult {
	char suffix[4];
	unsigned mult;
};
#define XSTR_STRTOU strtoul
#define XSTR_UTYPE_MAX UINT_MAX
unsigned int FAST_FUNC xstrtou_range_sfx(const char *numstr, int base,
		unsigned int lower,
		unsigned int upper,
		const struct suffix_mult *suffixes)
{
	unsigned int r;
	int old_errno;
	char *e;

	/* Disallow '-' and any leading whitespace. */
	if (*numstr == '-' || *numstr == '+' || isspace(*numstr))
		goto inval;

	/* Since this is a lib function, we're not allowed to reset errno to 0.
	 * Doing so could break an app that is deferring checking of errno.
	 * So, save the old value so that we can restore it if successful. */
	old_errno = errno;
	errno = 0;
	r = XSTR_STRTOU(numstr, &e, base);
	/* Do the initial validity check.  Note: The standards do not
	 * guarantee that errno is set if no digits were found.  So we
	 * must test for this explicitly. */
	if (errno || numstr == e)
		goto inval; /* error / no digits / illegal trailing chars */

	errno = old_errno;  /* Ok.  So restore errno. */

	/* Do optional suffix parsing.  Allow 'empty' suffix tables.
	 * Note that we also allow nul suffixes with associated multipliers,
	 * to allow for scaling of the numstr by some default multiplier. */
	if (suffixes) {
		while (suffixes->mult) {
			if (strcmp(suffixes->suffix, e) == 0) {
				if (XSTR_UTYPE_MAX / suffixes->mult < r)
					goto range; /* overflow! */
				r *= suffixes->mult;
				goto chk_range;
			}
			++suffixes;
		}
	}

	/* Note: trailing space is an error.
	 * It would be easy enough to allow though if desired. */
	if (*e)
		goto inval;
 chk_range:
	/* Finally, check for range limits. */
	if (r >= lower && r <= upper)
		return r;
 range:
	bb_error_msg_and_die("number %s is not in %llu..%llu range",
		numstr, (unsigned long long)lower,
		(unsigned long long)upper);
 inval:
	bb_error_msg_and_die("invalid number '%s'", numstr);
}


unsigned int FAST_FUNC xatou_range(const char *numstr,
                unsigned int lower,
                unsigned int upper)
{
        return xstrtou_range_sfx(numstr, 10, lower, upper, NULL);
}


int FAST_FUNC xatoi_positive(const char *numstr)
{
	return xatou_range(numstr, 0, INT_MAX);
}

uint16_t FAST_FUNC xatou16(const char *numstr)
{
	return xatou_range(numstr, 0, 0xffff);
}


//usage:#if !ENABLE_FEATURE_FANCY_PING
//usage:# define ping_trivial_usage
//usage:       "HOST"
//usage:# define ping_full_usage "\n\n"
//usage:       "Send ICMP ECHO_REQUEST packets to network hosts"
//usage:# define ping6_trivial_usage
//usage:       "HOST"
//usage:# define ping6_full_usage "\n\n"
//usage:       "Send ICMP ECHO_REQUEST packets to network hosts"
//usage:#else
//usage:# define ping_trivial_usage
//usage:       "[OPTIONS] HOST"
//usage:# define ping_full_usage "\n\n"
//usage:       "Send ICMP ECHO_REQUEST packets to network hosts\n"
//usage:	IF_PING6(
//usage:     "\n	-4,-6		Force IP or IPv6 name resolution"
//usage:	)
//usage:     "\n	-c CNT		Send only CNT pings"
//usage:     "\n	-s SIZE		Send SIZE data bytes in packets (default:56)"
//usage:     "\n	-t TTL		Set TTL"
//usage:     "\n	-I IFACE/IP	Use interface or IP address as source"
//usage:     "\n	-W SEC		Seconds to wait for the first response (default:10)"
//usage:     "\n			(after all -c CNT packets are sent)"
//usage:     "\n	-w SEC		Seconds until ping exits (default:infinite)"
//usage:     "\n			(can exit earlier with -c CNT)"
//usage:     "\n	-q		Quiet, only displays output at start"
//usage:     "\n			and when finished"
//usage:
//usage:# define ping6_trivial_usage
//usage:       "[OPTIONS] HOST"
//usage:# define ping6_full_usage "\n\n"
//usage:       "Send ICMP ECHO_REQUEST packets to network hosts\n"
//usage:     "\n	-c CNT		Send only CNT pings"
//usage:     "\n	-s SIZE		Send SIZE data bytes in packets (default:56)"
//usage:     "\n	-I IFACE/IP	Use interface or IP address as source"
//usage:     "\n	-q		Quiet, only displays output at start"
//usage:     "\n			and when finished"
//usage:
//usage:#endif
//usage:
//usage:#define ping_example_usage
//usage:       "$ ping localhost\n"
//usage:       "PING slag (127.0.0.1): 56 data bytes\n"
//usage:       "64 bytes from 127.0.0.1: icmp_seq=0 ttl=255 time=20.1 ms\n"
//usage:       "\n"
//usage:       "--- debian ping statistics ---\n"
//usage:       "1 packets transmitted, 1 packets received, 0% packet loss\n"
//usage:       "round-trip min/avg/max = 20.1/20.1/20.1 ms\n"
//usage:#define ping6_example_usage
//usage:       "$ ping6 ip6-localhost\n"
//usage:       "PING ip6-localhost (::1): 56 data bytes\n"
//usage:       "64 bytes from ::1: icmp6_seq=0 ttl=64 time=20.1 ms\n"
//usage:       "\n"
//usage:       "--- ip6-localhost ping statistics ---\n"
//usage:       "1 packets transmitted, 1 packets received, 0% packet loss\n"
//usage:       "round-trip min/avg/max = 20.1/20.1/20.1 ms\n"

#if ENABLE_PING6
# include <netinet/icmp6.h>
/* I see RENUMBERED constants in bits/in.h - !!?
 * What a fuck is going on with libc? Is it a glibc joke? */
# ifdef IPV6_2292HOPLIMIT
#  undef IPV6_HOPLIMIT
#  define IPV6_HOPLIMIT IPV6_2292HOPLIMIT
# endif
#endif

enum {
	DEFDATALEN = 56,
	MAXIPLEN = 60,
	MAXICMPLEN = 76,
	MAX_DUP_CHK = (8 * 128),
	MAXWAIT = 10,
	PINGINTERVAL = 1, /* 1 second */
	pingsock = 0,
};

static int using_dgram;
static void
#if ENABLE_PING6
create_icmp_socket(len_and_sockaddr *lsa)
#else
create_icmp_socket(void)
#define create_icmp_socket(lsa) create_icmp_socket()
#endif
{
	int sock;
#if ENABLE_PING6
	if (lsa->u.sa.sa_family == AF_INET6)
		sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
	else
#endif
		sock = socket(AF_INET, SOCK_RAW, 1); /* 1 == ICMP */
	if (sock < 0) {
		if (errno != EPERM)
			bb_perror_msg_and_die(bb_msg_can_not_create_raw_socket);
#if defined(__linux__) || defined(__APPLE__)
		/* We don't have root privileges.  Try SOCK_DGRAM instead.
		 * Linux needs net.ipv4.ping_group_range for this to work.
		 * MacOSX allows ICMP_ECHO, ICMP_TSTAMP or ICMP_MASKREQ
		 */
#if ENABLE_PING6
		if (lsa->u.sa.sa_family == AF_INET6)
			sock = socket(AF_INET6, SOCK_DGRAM, IPPROTO_ICMPV6);
		else
#endif
			sock = socket(AF_INET, SOCK_DGRAM, 1); /* 1 == ICMP */
		if (sock < 0)
#endif
		bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
		using_dgram = 1;
	}

	xmove_fd(sock, pingsock);
}

#if !ENABLE_FEATURE_FANCY_PING

/* Simple version */

struct globals {
	char *hostname;
	char packet[DEFDATALEN + MAXIPLEN + MAXICMPLEN];
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define INIT_G() do { } while (0)

static void noresp(int ign UNUSED_PARAM)
{
	printf("No response from %s\n", G.hostname);
	exit(EXIT_FAILURE);
}

static void ping4(len_and_sockaddr *lsa)
{
	struct icmp *pkt;
	int c;

	pkt = (struct icmp *) G.packet;
	/*memset(pkt, 0, sizeof(G.packet)); already is */
	pkt->icmp_type = ICMP_ECHO;
	pkt->icmp_cksum = inet_cksum((uint16_t *) pkt, sizeof(G.packet));

	xsendto(pingsock, G.packet, DEFDATALEN + ICMP_MINLEN, &lsa->u.sa, lsa->len);

	/* listen for replies */
	while (1) {
#if 0
		struct sockaddr_in from;
		socklen_t fromlen = sizeof(from);

		c = recvfrom(pingsock, G.packet, sizeof(G.packet), 0,
				(struct sockaddr *) &from, &fromlen);
#else
		c = recv(pingsock, G.packet, sizeof(G.packet), 0);
#endif
		if (c < 0) {
			if (errno != EINTR)
				bb_perror_msg("recvfrom");
			continue;
		}
		if (c >= 76 || using_dgram && (c == 64)) {			/* ip + icmp */
			if(!using_dgram) {
				struct iphdr *iphdr = (struct iphdr *) G.packet;

				pkt = (struct icmp *) (G.packet + (iphdr->ihl << 2));	/* skip ip hdr */
			} else pkt = (struct icmp *) G.packet;
			if (pkt->icmp_type == ICMP_ECHOREPLY)
				break;
		}
	}
	if (ENABLE_FEATURE_CLEAN_UP)
		close(pingsock);
}

#if ENABLE_PING6
static void ping6(len_and_sockaddr *lsa)
{
	struct icmp6_hdr *pkt;
	int c;
	int sockopt;

	pkt = (struct icmp6_hdr *) G.packet;
	/*memset(pkt, 0, sizeof(G.packet)); already is */
	pkt->icmp6_type = ICMP6_ECHO_REQUEST;

	sockopt = offsetof(struct icmp6_hdr, icmp6_cksum);
	setsockopt(pingsock, SOL_RAW, IPV6_CHECKSUM, &sockopt, sizeof(sockopt));

	xsendto(pingsock, G.packet, DEFDATALEN + sizeof(struct icmp6_hdr), &lsa->u.sa, lsa->len);

	/* listen for replies */
	while (1) {
#if 0
		struct sockaddr_in6 from;
		socklen_t fromlen = sizeof(from);

		c = recvfrom(pingsock, G.packet, sizeof(G.packet), 0,
				(struct sockaddr *) &from, &fromlen);
#else
		c = recv(pingsock, G.packet, sizeof(G.packet), 0);
#endif
		if (c < 0) {
			if (errno != EINTR)
				bb_perror_msg("recvfrom");
			continue;
		}
		if (c >= ICMP_MINLEN) {	/* icmp6_hdr */
			if (pkt->icmp6_type == ICMP6_ECHO_REPLY)
				break;
		}
	}
	if (ENABLE_FEATURE_CLEAN_UP)
		close(pingsock);
}
#endif

#if !ENABLE_PING6
# define common_ping_main(af, argv) common_ping_main(argv)
#endif
static int common_ping_main(sa_family_t af, char **argv)
{
	len_and_sockaddr *lsa;

	INIT_G();

#if ENABLE_PING6
	while ((++argv)[0] && argv[0][0] == '-') {
		if (argv[0][1] == '4') {
			af = AF_INET;
			continue;
		}
		if (argv[0][1] == '6') {
			af = AF_INET6;
			continue;
		}
		bb_show_usage();
	}
#else
	argv++;
#endif

	G.hostname = *argv;
	if (!G.hostname)
		bb_show_usage();

#if ENABLE_PING6
	lsa = xhost_and_af2sockaddr(G.hostname, 0, af);
#else
	lsa = xhost_and_af2sockaddr(G.hostname, 0, AF_INET);
#endif
	/* Set timer _after_ DNS resolution */
	signal(SIGALRM, noresp);
	// XXXX reenable alarm	alarm(5); /* give the host 5000ms to respond */

	create_icmp_socket(lsa);
#if ENABLE_PING6
	if (lsa->u.sa.sa_family == AF_INET6)
		ping6(lsa);
	else
#endif
		ping4(lsa);
	printf("%s is alive!\n", G.hostname);
	return EXIT_SUCCESS;
}


#else /* FEATURE_FANCY_PING */


/* Full(er) version */

#define OPT_STRING ("qvc:s:t:w:W:I:n4" IF_PING6("6"))
enum {
	OPT_QUIET = 1 << 0,
	OPT_VERBOSE = 1 << 1,
	OPT_c = 1 << 2,
	OPT_s = 1 << 3,
	OPT_t = 1 << 4,
	OPT_w = 1 << 5,
	OPT_W = 1 << 6,
	OPT_I = 1 << 7,
	/*OPT_n = 1 << 8, - ignored */
	OPT_IPV4 = 1 << 9,
	OPT_IPV6 = (1 << 10) * ENABLE_PING6,
};


struct globals {
	int if_index;
	char *str_I;
	len_and_sockaddr *source_lsa;
	unsigned datalen;
	unsigned pingcount; /* must be int-sized */
	unsigned opt_ttl;
	unsigned long ntransmitted, nreceived, nrepeats;
	uint16_t myid;
	unsigned tmin, tmax; /* in us */
	unsigned long long tsum; /* in us, sum of all times */
	unsigned deadline;
	unsigned timeout;
	unsigned total_secs;
	unsigned sizeof_rcv_packet;
	char *rcv_packet; /* [datalen + MAXIPLEN + MAXICMPLEN] */
	void *snd_packet; /* [datalen + ipv4/ipv6_const] */
	const char *hostname;
	const char *dotted;
	union {
		struct sockaddr sa;
		struct sockaddr_in sin;
#if ENABLE_PING6
		struct sockaddr_in6 sin6;
#endif
	} pingaddr;
	unsigned char rcvd_tbl[MAX_DUP_CHK / 8];
} FIX_ALIASING;
#define G (*(struct globals*)&bb_common_bufsiz1)
#define if_index     (G.if_index    )
#define source_lsa   (G.source_lsa  )
#define str_I        (G.str_I       )
#define datalen      (G.datalen     )
#define pingcount    (G.pingcount   )
#define opt_ttl      (G.opt_ttl     )
#define myid         (G.myid        )
#define tmin         (G.tmin        )
#define tmax         (G.tmax        )
#define tsum         (G.tsum        )
#define deadline     (G.deadline    )
#define timeout      (G.timeout     )
#define total_secs   (G.total_secs  )
#define hostname     (G.hostname    )
#define dotted       (G.dotted      )
#define pingaddr     (G.pingaddr    )
#define rcvd_tbl     (G.rcvd_tbl    )
void BUG_ping_globals_too_big(void);
#define INIT_G() do { \
	if (sizeof(G) > COMMON_BUFSIZE) \
		BUG_ping_globals_too_big(); \
	datalen = DEFDATALEN; \
	timeout = MAXWAIT; \
	tmin = UINT_MAX; \
} while (0)


#define BYTE(bit)	rcvd_tbl[(bit)>>3]
#define MASK(bit)	(1 << ((bit) & 7))
#define SET(bit)	(BYTE(bit) |= MASK(bit))
#define CLR(bit)	(BYTE(bit) &= (~MASK(bit)))
#define TST(bit)	(BYTE(bit) & MASK(bit))

static void print_stats_and_exit(int junk) NORETURN;
static void print_stats_and_exit(int junk UNUSED_PARAM)
{
	unsigned long ul;
	unsigned long nrecv;

	signal(SIGINT, SIG_IGN);

	nrecv = G.nreceived;
	printf("\n--- %s ping statistics ---\n"
		"%lu packets transmitted, "
		"%lu packets received, ",
		hostname, G.ntransmitted, nrecv
	);
	if (G.nrepeats)
		printf("%lu duplicates, ", G.nrepeats);
	ul = G.ntransmitted;
	if (ul != 0)
		ul = (ul - nrecv) * 100 / ul;
	printf("%lu%% packet loss\n", ul);
	if (tmin != UINT_MAX) {
		unsigned tavg = tsum / (nrecv + G.nrepeats);
		printf("round-trip min/avg/max = %u.%03u/%u.%03u/%u.%03u ms\n",
			tmin / 1000, tmin % 1000,
			tavg / 1000, tavg % 1000,
			tmax / 1000, tmax % 1000);
	}
	/* if condition is true, exit with 1 -- 'failure' */
	exit(nrecv == 0 || (deadline && nrecv < pingcount));
}

static void sendping_tail(void (*sp)(int), int size_pkt)
{
	int sz;

	CLR((uint16_t)G.ntransmitted % MAX_DUP_CHK);
	G.ntransmitted++;

	size_pkt += datalen;

	/* sizeof(pingaddr) can be larger than real sa size, but I think
	 * it doesn't matter */
	sz = xsendto(pingsock, G.snd_packet, size_pkt, &pingaddr.sa, sizeof(pingaddr));
	if (sz != size_pkt)
		bb_error_msg_and_die(bb_msg_write_error);

	if (pingcount == 0 || deadline || G.ntransmitted < pingcount) {
		/* Didn't send all pings yet - schedule next in 1s */
		signal(SIGALRM, sp);
		if (deadline) {
			total_secs += PINGINTERVAL;
			if (total_secs >= deadline)
				signal(SIGALRM, print_stats_and_exit);
		}
		alarm(PINGINTERVAL);
	} else { /* -c NN, and all NN are sent (and no deadline) */
		/* Wait for the last ping to come back.
		 * -W timeout: wait for a response in seconds.
		 * Affects only timeout in absense of any responses,
		 * otherwise ping waits for two RTTs. */
		unsigned expire = timeout;

		if (G.nreceived) {
			/* approx. 2*tmax, in seconds (2 RTT) */
			expire = tmax / (512*1024);
			if (expire == 0)
				expire = 1;
		}
		signal(SIGALRM, print_stats_and_exit);
		alarm(expire);
	}
}

static void sendping4(int junk UNUSED_PARAM)
{
	struct icmp *pkt = G.snd_packet;

	//memset(pkt, 0, datalen + ICMP_MINLEN + 4); - G.snd_packet was xzalloced
	pkt->icmp_type = ICMP_ECHO;
	/*pkt->icmp_code = 0;*/
	pkt->icmp_cksum = 0; /* cksum is calculated with this field set to 0 */
	pkt->icmp_seq = htons(G.ntransmitted); /* don't ++ here, it can be a macro */
	pkt->icmp_id = myid;

	/* If datalen < 4, we store timestamp _past_ the packet,
	 * but it's ok - we allocated 4 extra bytes in xzalloc() just in case.
	 */
	/*if (datalen >= 4)*/
		/* No hton: we'll read it back on the same machine */
		*(uint32_t*)&pkt->icmp_dun = monotonic_us();

	pkt->icmp_cksum = inet_cksum((uint16_t *) pkt, datalen + ICMP_MINLEN);

	sendping_tail(sendping4, ICMP_MINLEN);
}
#if ENABLE_PING6
static void sendping6(int junk UNUSED_PARAM)
{
	struct icmp6_hdr *pkt = G.snd_packet;

	//memset(pkt, 0, datalen + sizeof(struct icmp6_hdr) + 4);
	pkt->icmp6_type = ICMP6_ECHO_REQUEST;
	/*pkt->icmp6_code = 0;*/
	/*pkt->icmp6_cksum = 0;*/
	pkt->icmp6_seq = htons(G.ntransmitted); /* don't ++ here, it can be a macro */
	pkt->icmp6_id = myid;

	/*if (datalen >= 4)*/
		*(bb__aliased_uint32_t*)(&pkt->icmp6_data8[4]) = monotonic_us();

	//TODO? pkt->icmp_cksum = inet_cksum(...);

	sendping_tail(sendping6, sizeof(struct icmp6_hdr));
}
#endif

static const char *icmp_type_name(int id)
{
	switch (id) {
	case ICMP_ECHOREPLY:      return "Echo Reply";
	case ICMP_DEST_UNREACH:   return "Destination Unreachable";
	case ICMP_SOURCE_QUENCH:  return "Source Quench";
	case ICMP_REDIRECT:       return "Redirect (change route)";
	case ICMP_ECHO:           return "Echo Request";
	case ICMP_TIME_EXCEEDED:  return "Time Exceeded";
	case ICMP_PARAMETERPROB:  return "Parameter Problem";
	case ICMP_TIMESTAMP:      return "Timestamp Request";
	case ICMP_TIMESTAMPREPLY: return "Timestamp Reply";
	case ICMP_INFO_REQUEST:   return "Information Request";
	case ICMP_INFO_REPLY:     return "Information Reply";
	case ICMP_ADDRESS:        return "Address Mask Request";
	case ICMP_ADDRESSREPLY:   return "Address Mask Reply";
	default:                  return "unknown ICMP type";
	}
}
#if ENABLE_PING6
/* RFC3542 changed some definitions from RFC2292 for no good reason, whee!
 * the newer 3542 uses a MLD_ prefix where as 2292 uses ICMP6_ prefix */
#ifndef MLD_LISTENER_QUERY
# define MLD_LISTENER_QUERY ICMP6_MEMBERSHIP_QUERY
#endif
#ifndef MLD_LISTENER_REPORT
# define MLD_LISTENER_REPORT ICMP6_MEMBERSHIP_REPORT
#endif
#ifndef MLD_LISTENER_REDUCTION
# define MLD_LISTENER_REDUCTION ICMP6_MEMBERSHIP_REDUCTION
#endif
static const char *icmp6_type_name(int id)
{
	switch (id) {
	case ICMP6_DST_UNREACH:      return "Destination Unreachable";
	case ICMP6_PACKET_TOO_BIG:   return "Packet too big";
	case ICMP6_TIME_EXCEEDED:    return "Time Exceeded";
	case ICMP6_PARAM_PROB:       return "Parameter Problem";
	case ICMP6_ECHO_REPLY:       return "Echo Reply";
	case ICMP6_ECHO_REQUEST:     return "Echo Request";
	case MLD_LISTENER_QUERY:     return "Listener Query";
	case MLD_LISTENER_REPORT:    return "Listener Report";
	case MLD_LISTENER_REDUCTION: return "Listener Reduction";
	default:                     return "unknown ICMP type";
	}
}
#endif

static void unpack_tail(int sz, uint32_t *tp,
		const char *from_str,
		uint16_t recv_seq, int ttl)
{
	unsigned char *b, m;
	const char *dupmsg = " (DUP!)";
	unsigned triptime = triptime; /* for gcc */

	if (tp) {
		/* (int32_t) cast is for hypothetical 64-bit unsigned */
		/* (doesn't hurt 32-bit real-world anyway) */
		triptime = (int32_t) ((uint32_t)monotonic_us() - *tp);
		tsum += triptime;
		if (triptime < tmin)
			tmin = triptime;
		if (triptime > tmax)
			tmax = triptime;
	}

	b = &BYTE(recv_seq % MAX_DUP_CHK);
	m = MASK(recv_seq % MAX_DUP_CHK);
	/*if TST(recv_seq % MAX_DUP_CHK):*/
	if (*b & m) {
		++G.nrepeats;
	} else {
		/*SET(recv_seq % MAX_DUP_CHK):*/
		*b |= m;
		++G.nreceived;
		dupmsg += 7;
	}

	if (option_mask32 & OPT_QUIET)
		return;

	printf("%d bytes from %s: seq=%u ttl=%d", sz,
		from_str, recv_seq, ttl);
	if (tp)
		printf(" time=%u.%03u ms", triptime / 1000, triptime % 1000);
	puts(dupmsg);
	fflush_all();
}
static void unpack4(char *buf, int sz, struct sockaddr_in *from)
{
	struct iphdr *iphdr;
	struct icmp *icmppkt;
	int hlen;

	/* discard if too short */
	if (sz < (datalen + ICMP_MINLEN))
		return;
	if(!using_dgram) {
		/* check IP header */
		iphdr = (struct iphdr *) buf;
		hlen = iphdr->ihl << 2;
		sz -= hlen;
		icmppkt = (struct icmp *) (buf + hlen);
	} else icmppkt = (struct icmp *) buf;

	if (icmppkt->icmp_id != myid)
		return;				/* not our ping */

	if (icmppkt->icmp_type == ICMP_ECHOREPLY) {
		uint16_t recv_seq = ntohs(icmppkt->icmp_seq);
		uint32_t *tp = NULL;

		if (sz >= ICMP_MINLEN + sizeof(uint32_t))
			tp = (uint32_t *) icmppkt->icmp_data;
		unpack_tail(sz, tp,
			inet_ntoa(*(struct in_addr *) &from->sin_addr.s_addr),
			recv_seq, using_dgram ? 42 : iphdr->ttl);
	} else if (icmppkt->icmp_type != ICMP_ECHO) {
		bb_error_msg("warning: got ICMP %d (%s)",
				icmppkt->icmp_type,
				icmp_type_name(icmppkt->icmp_type));
	}
}
#if ENABLE_PING6
static void unpack6(char *packet, int sz, struct sockaddr_in6 *from, int hoplimit)
{
	struct icmp6_hdr *icmppkt;
	char buf[INET6_ADDRSTRLEN];

	/* discard if too short */
	if (sz < (datalen + sizeof(struct icmp6_hdr)))
		return;

	icmppkt = (struct icmp6_hdr *) packet;
	if (icmppkt->icmp6_id != myid)
		return;				/* not our ping */

	if (icmppkt->icmp6_type == ICMP6_ECHO_REPLY) {
		uint16_t recv_seq = ntohs(icmppkt->icmp6_seq);
		uint32_t *tp = NULL;

		if (sz >= sizeof(struct icmp6_hdr) + sizeof(uint32_t))
			tp = (uint32_t *) &icmppkt->icmp6_data8[4];
		unpack_tail(sz, tp,
			inet_ntop(AF_INET6, &from->sin6_addr,
					buf, sizeof(buf)),
			recv_seq, hoplimit);
	} else if (icmppkt->icmp6_type != ICMP6_ECHO_REQUEST) {
		bb_error_msg("warning: got ICMP %d (%s)",
				icmppkt->icmp6_type,
				icmp6_type_name(icmppkt->icmp6_type));
	}
}
#endif

static void ping4(len_and_sockaddr *lsa)
{
	int sockopt;

	pingaddr.sin = lsa->u.sin;
	if (source_lsa && !using_dgram) {
		if (setsockopt(pingsock, IPPROTO_IP, IP_MULTICAST_IF,
				&source_lsa->u.sa, source_lsa->len))
			bb_error_msg_and_die("can't set multicast source interface");
		xbind(pingsock, &source_lsa->u.sa, source_lsa->len);
	} else if(using_dgram) {
		struct sockaddr_in sa;
		socklen_t sl;

		sa.sin_family = AF_INET;
		sa.sin_port = 0;
		sa.sin_addr.s_addr = source_lsa ?
			source_lsa->u.sin.sin_addr.s_addr : 0;
		sl = sizeof(sa);

		if (bind(pingsock, (struct sockaddr *) &sa, sl) == -1) {
			perror("bind");
			exit(2);
		}

		if (getsockname(pingsock, (struct sockaddr *) &sa, &sl) == -1) {
			perror("getsockname");
			exit(2);
		}
		myid = sa.sin_port;
	}

	/* enable broadcast pings */
	setsockopt_broadcast(pingsock);

	/* set recv buf (needed if we can get lots of responses: flood ping,
	 * broadcast ping etc) */
	sockopt = (datalen * 2) + 7 * 1024; /* giving it a bit of extra room */
	setsockopt(pingsock, SOL_SOCKET, SO_RCVBUF, &sockopt, sizeof(sockopt));

	if (opt_ttl != 0) {
		setsockopt(pingsock, IPPROTO_IP, IP_TTL, &opt_ttl, sizeof(opt_ttl));
		/* above doesnt affect packets sent to bcast IP, so... */
		setsockopt(pingsock, IPPROTO_IP, IP_MULTICAST_TTL, &opt_ttl, sizeof(opt_ttl));
	}

	if(using_dgram) {
		int hold = 65536;
		if (setsockopt(pingsock, SOL_IP, IP_RECVTTL, (char *)&hold, sizeof(hold)))
			perror("WARNING: setsockopt(IP_RECVTTL)");
		if (setsockopt(pingsock, SOL_IP, IP_RETOPTS, (char *)&hold, sizeof(hold)))
			perror("WARNING: setsockopt(IP_RETOPTS)");

	}

	signal(SIGINT, print_stats_and_exit);

	/* start the ping's going ... */
	sendping4(0);

	/* listen for replies */
	while (1) {
		struct sockaddr_in from;
		socklen_t fromlen = (socklen_t) sizeof(from);
		int c;

		c = recvfrom(pingsock, G.rcv_packet, G.sizeof_rcv_packet, 0,
				(struct sockaddr *) &from, &fromlen);
		if (c < 0) {
			if (errno != EINTR)
				bb_perror_msg("recvfrom");
			continue;
		}
		unpack4(G.rcv_packet, c, &from);
		if (pingcount && G.nreceived >= pingcount)
			break;
	}
}
#if ENABLE_PING6
extern int BUG_bad_offsetof_icmp6_cksum(void);
static void ping6(len_and_sockaddr *lsa)
{
	int sockopt;
	struct msghdr msg;
	struct sockaddr_in6 from;
	struct iovec iov;
	char control_buf[CMSG_SPACE(36)];

	pingaddr.sin6 = lsa->u.sin6;
	if (source_lsa && !using_dgram)
		xbind(pingsock, &source_lsa->u.sa, source_lsa->len);
	else if(using_dgram) {
                struct sockaddr_in6 sa = {0};
                socklen_t sl;

                sa.sin6_family = AF_INET6;
                sa.sin6_port = 0;
		if(source_lsa) {
			memcpy(&sa.sin6_addr, &source_lsa->u.sin6.sin6_addr, sizeof(struct in6_addr));
		}
                sl = sizeof(sa);

                if (bind(pingsock, (struct sockaddr *) &sa, sl) == -1) {
                        perror("bind");
                        exit(2);
                }

                if (getsockname(pingsock, (struct sockaddr *) &sa, &sl) == -1) {
                        perror("getsockname");
                        exit(2);
                }
                myid = sa.sin6_port;
	}

#ifdef ICMP6_FILTER
	if(!using_dgram)
	{
		struct icmp6_filter filt;
		if (!(option_mask32 & OPT_VERBOSE)) {
			ICMP6_FILTER_SETBLOCKALL(&filt);
			ICMP6_FILTER_SETPASS(ICMP6_ECHO_REPLY, &filt);
		} else {
			ICMP6_FILTER_SETPASSALL(&filt);
		}
		if (setsockopt(pingsock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt,
					sizeof(filt)) < 0)
			bb_error_msg_and_die("setsockopt(ICMP6_FILTER)");
	}
#endif /*ICMP6_FILTER*/

	/* enable broadcast pings */
	setsockopt_broadcast(pingsock);

	/* set recv buf (needed if we can get lots of responses: flood ping,
	 * broadcast ping etc) */
	sockopt = (datalen * 2) + 7 * 1024; /* giving it a bit of extra room */
	setsockopt(pingsock, SOL_SOCKET, SO_RCVBUF, &sockopt, sizeof(sockopt));

	sockopt = offsetof(struct icmp6_hdr, icmp6_cksum);
	if (offsetof(struct icmp6_hdr, icmp6_cksum) != 2)
		BUG_bad_offsetof_icmp6_cksum();
	setsockopt(pingsock, SOL_RAW, IPV6_CHECKSUM, &sockopt, sizeof(sockopt));

	/* request ttl info to be returned in ancillary data */
	setsockopt(pingsock, SOL_IPV6, IPV6_HOPLIMIT, &const_int_1, sizeof(const_int_1));

	if (if_index)
		pingaddr.sin6.sin6_scope_id = if_index;

	signal(SIGINT, print_stats_and_exit);

	/* start the ping's going ... */
	sendping6(0);

	/* listen for replies */
	msg.msg_name = &from;
	msg.msg_namelen = sizeof(from);
	msg.msg_iov = &iov;
	msg.msg_iovlen = 1;
	msg.msg_control = control_buf;
	iov.iov_base = G.rcv_packet;
	iov.iov_len = G.sizeof_rcv_packet;
	while (1) {
		int c;
		struct cmsghdr *mp;
		int hoplimit = -1;
		msg.msg_controllen = sizeof(control_buf);

		c = recvmsg(pingsock, &msg, 0);
		if (c < 0) {
			if (errno != EINTR)
				bb_perror_msg("recvfrom");
			continue;
		}
		for (mp = CMSG_FIRSTHDR(&msg); mp; mp = CMSG_NXTHDR(&msg, mp)) {
			if (mp->cmsg_level == SOL_IPV6
			 && mp->cmsg_type == IPV6_HOPLIMIT
			 /* don't check len - we trust the kernel: */
			 /* && mp->cmsg_len >= CMSG_LEN(sizeof(int)) */
			) {
				/*hoplimit = *(int*)CMSG_DATA(mp); - unaligned access */
				move_from_unaligned_int(hoplimit, CMSG_DATA(mp));
			}
		}
		unpack6(G.rcv_packet, c, &from, hoplimit);
		if (pingcount && G.nreceived >= pingcount)
			break;
	}
}
#endif

static void ping(len_and_sockaddr *lsa)
{
	printf("PING %s (%s)", hostname, dotted);
	if (source_lsa) {
		printf(" from %s",
			xmalloc_sockaddr2dotted_noport(&source_lsa->u.sa));
	}
	printf(": %d data bytes\n", datalen);

	create_icmp_socket(lsa);
	/* untested whether "-I addr" really works for IPv6: */
	if (str_I)
		setsockopt_bindtodevice(pingsock, str_I);

	G.sizeof_rcv_packet = datalen + MAXIPLEN + MAXICMPLEN;
	G.rcv_packet = xzalloc(G.sizeof_rcv_packet);
#if ENABLE_PING6
	if (lsa->u.sa.sa_family == AF_INET6) {
		/* +4 reserves a place for timestamp, which may end up sitting
		 * _after_ packet. Saves one if() - see sendping4/6() */
		G.snd_packet = xzalloc(datalen + sizeof(struct icmp6_hdr) + 4);
		ping6(lsa);
	} else
#endif
	{
		G.snd_packet = xzalloc(datalen + ICMP_MINLEN + 4);
		ping4(lsa);
	}
}

static int common_ping_main(int opt, char **argv)
{
	len_and_sockaddr *lsa;
	char *str_s;

	INIT_G();

	/* exactly one argument needed; -v and -q don't mix; -c NUM, -t NUM, -w NUM, -W NUM */
	opt_complementary = "=1:q--v:v--q:c+:t+:w+:W+";
	opt |= getopt32(argv, OPT_STRING, &pingcount, &str_s, &opt_ttl, &deadline, &timeout, &str_I);
	if (opt & OPT_s)
		datalen = xatou16(str_s); // -s
	if (opt & OPT_I) { // -I
		if_index = if_nametoindex(str_I);
		if (!if_index) {
			/* TODO: I'm not sure it takes IPv6 unless in [XX:XX..] format */
			source_lsa = xdotted2sockaddr(str_I, 0);
			str_I = NULL; /* don't try to bind to device later */
		}
	}
	if(!using_dgram) myid = (uint16_t) getpid();
	hostname = argv[optind];
#if ENABLE_PING6
	{
		sa_family_t af = AF_UNSPEC;
		if (opt & OPT_IPV4)
			af = AF_INET;
		if (opt & OPT_IPV6)
			af = AF_INET6;
		lsa = xhost_and_af2sockaddr(hostname, 0, af);
	}
#else
	lsa = xhost_and_af2sockaddr(hostname, 0, AF_INET);
#endif

	if (source_lsa && source_lsa->u.sa.sa_family != lsa->u.sa.sa_family)
		/* leaking it here... */
		source_lsa = NULL;

	dotted = xmalloc_sockaddr2dotted_noport(&lsa->u.sa);
	ping(lsa);
	print_stats_and_exit(EXIT_SUCCESS);
	/*return EXIT_SUCCESS;*/
}
#endif /* FEATURE_FANCY_PING */


int ping_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int ping_main(int argc UNUSED_PARAM, char **argv)
{
#if !ENABLE_FEATURE_FANCY_PING
	return common_ping_main(AF_UNSPEC, argv);
#else
	return common_ping_main(0, argv);
#endif
}

#if ENABLE_PING6
int ping6_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int ping6_main(int argc UNUSED_PARAM, char **argv)
{
# if !ENABLE_FEATURE_FANCY_PING
	return common_ping_main(AF_INET6, argv);
# else
	return common_ping_main(OPT_IPV6, argv);
# endif
}
#endif

int main(int argc, char** argv) {
	if(argc > 1 && !strcmp(argv[1], "-6"))
		return ping6_main(argc, argv);
	else
		return ping_main(argc, argv);
}

/* from ping6.c:
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Mike Muuss.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
 *		ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
 *
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

in order to make it work for regular users, do

echo "1000 2147483647" > /proc/sys/net/ipv4/ping_group_range

as root

Nice utility - can you give me a quick "usage". i want to ping icmpas well as normal ports