X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=src%2Fliboping.c;h=eca5c162d578655dc3cd7e7ea1b1f473d4c80e14;hb=fe85c13e095749191a4dc7bc5e066b1c922702f6;hp=776f24f09e2af9f6b25ee248f759a76514ce3867;hpb=d717d41928fab9354e88d91ef1996151565012d8;p=liboping.git

diff --git a/src/liboping.c b/src/liboping.c
index 776f24f..eca5c16 100644
--- a/src/liboping.c
+++ b/src/liboping.c
@@ -1,6 +1,6 @@
 /**
  * Object oriented C module to send ICMP and ICMPv6 `echo's.
- * Copyright (C) 2006-2011  Florian octo Forster <ff at octo.it>
+ * Copyright (C) 2006-2017  Florian octo Forster <ff at octo.it>
  *
  * This library is free software; you can redistribute it and/or modify it
  * under the terms of the GNU Lesser General Public License as published by the
@@ -17,6 +17,10 @@
  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#ifdef __APPLE__
+#define __APPLE_USE_RFC_3542
+#endif
+
 #if HAVE_CONFIG_H
 # include <config.h>
 #endif
@@ -142,10 +146,13 @@ struct pingobj
 
 	char                    *device;
 
+	char                    set_mark;
+	int                     mark;
+
 	char                     errmsg[PING_ERRMSG_LEN];
 
 	pinghost_t              *head;
-	pinghost_t		*table[PING_TABLE_LEN];
+	pinghost_t              *table[PING_TABLE_LEN];
 };
 
 /*
@@ -296,23 +303,20 @@ static pinghost_t *ping_receive_ipv4 (pingobj_t *obj, char *buffer,
 	buffer     += ip_hdr_len;
 	buffer_len -= ip_hdr_len;
 
-	if (buffer_len < sizeof (struct icmp))
+	if (buffer_len < ICMP_MINLEN)
 		return (NULL);
 
 	icmp_hdr = (struct icmp *) buffer;
-	buffer     += sizeof (struct icmp);
-	buffer_len -= sizeof (struct icmp);
-
 	if (icmp_hdr->icmp_type != ICMP_ECHOREPLY)
 	{
-		dprintf ("Unexpected ICMP type: %i\n", icmp_hdr->icmp_type);
+		dprintf ("Unexpected ICMP type: %"PRIu8"\n", icmp_hdr->icmp_type);
 		return (NULL);
 	}
 
 	recv_checksum = icmp_hdr->icmp_cksum;
+	/* This writes to buffer. */
 	icmp_hdr->icmp_cksum = 0;
-	calc_checksum = ping_icmp4_checksum ((char *) icmp_hdr,
-			sizeof (struct icmp) + buffer_len);
+	calc_checksum = ping_icmp4_checksum (buffer, buffer_len);
 
 	if (recv_checksum != calc_checksum)
 	{
@@ -389,12 +393,12 @@ static pinghost_t *ping_receive_ipv6 (pingobj_t *obj, char *buffer,
 
 	pinghost_t *ptr;
 
-	if (buffer_len < sizeof (struct icmp6_hdr))
+	if (buffer_len < ICMP_MINLEN)
 		return (NULL);
 
 	icmp_hdr = (struct icmp6_hdr *) buffer;
-	buffer     += sizeof (struct icmp);
-	buffer_len -= sizeof (struct icmp);
+	buffer     += ICMP_MINLEN;
+	buffer_len -= ICMP_MINLEN;
 
 	if (icmp_hdr->icmp6_type != ICMP6_ECHO_REPLY)
 	{
@@ -454,7 +458,7 @@ static int ping_receive_one (pingobj_t *obj, struct timeval *now, int addrfam)
 	pinghost_t *host = NULL;
 	int recv_ttl;
 	uint8_t recv_qos;
-	
+
 	/*
 	 * Set up the receive buffer..
 	 */
@@ -545,6 +549,7 @@ static int ping_receive_one (pingobj_t *obj, struct timeval *now, int addrfam)
 						sizeof (recv_qos));
 				dprintf ("TOSv6 = 0x%02"PRIx8";\n", recv_qos);
 			} else
+#ifdef IPV6_HOPLIMIT
 			if (cmsg->cmsg_type == IPV6_HOPLIMIT)
 			{
 				memcpy (&recv_ttl, CMSG_DATA (cmsg),
@@ -552,6 +557,25 @@ static int ping_receive_one (pingobj_t *obj, struct timeval *now, int addrfam)
 				dprintf ("TTLv6 = %i;\n", recv_ttl);
 			}
 			else
+#endif
+#ifdef IPV6_UNICAST_HOPS
+			if (cmsg->cmsg_type == IPV6_UNICAST_HOPS)
+			{
+				memcpy (&recv_ttl, CMSG_DATA (cmsg),
+						sizeof (recv_ttl));
+				dprintf ("TTLv6 = %i;\n", recv_ttl);
+			}
+			else
+#endif
+#ifdef IPV6_MULTICAST_HOPS
+			if (cmsg->cmsg_type == IPV6_MULTICAST_HOPS)
+			{
+				memcpy (&recv_ttl, CMSG_DATA (cmsg),
+						sizeof (recv_ttl));
+				dprintf ("TTLv6 = %i;\n", recv_ttl);
+			}
+			else
+#endif
 			{
 				dprintf ("Not handling option %i.\n",
 						cmsg->cmsg_type);
@@ -655,29 +679,28 @@ static int ping_send_one_ipv4 (pingobj_t *obj, pinghost_t *ph, int fd)
 	struct icmp *icmp4;
 	int status;
 
-	char buf[4096];
-	int  buflen;
+	char   buf[4096] = {0};
+	size_t buflen;
 
 	char *data;
-	int   datalen;
+	size_t datalen;
 
 	dprintf ("ph->hostname = %s\n", ph->hostname);
 
-	memset (buf, '\0', sizeof (buf));
 	icmp4 = (struct icmp *) buf;
-	data  = (char *) (icmp4 + 1);
+	*icmp4 = (struct icmp) {
+		.icmp_type = ICMP_ECHO,
+		.icmp_id   = htons (ph->ident),
+		.icmp_seq  = htons (ph->sequence),
+	};
 
-	icmp4->icmp_type  = ICMP_ECHO;
-	icmp4->icmp_code  = 0;
-	icmp4->icmp_cksum = 0;
-	icmp4->icmp_id    = htons (ph->ident);
-	icmp4->icmp_seq   = htons (ph->sequence);
+	datalen = strlen (ph->data);
+	buflen = ICMP_MINLEN + datalen;
+	if (sizeof (buf) < buflen)
+		return (EINVAL);
 
-	buflen = 4096 - sizeof (struct icmp);
-	strncpy (data, ph->data, buflen);
-	datalen = strlen (data);
-
-	buflen = datalen + sizeof (struct icmp);
+	data  = buf + ICMP_MINLEN;
+	memcpy (data, ph->data, datalen);
 
 	icmp4->icmp_cksum = ping_icmp4_checksum (buf, buflen);
 
@@ -700,7 +723,7 @@ static int ping_send_one_ipv6 (pingobj_t *obj, pinghost_t *ph, int fd)
 	struct icmp6_hdr *icmp6;
 	int status;
 
-	char buf[4096];
+	char buf[4096] = {0};
 	int  buflen;
 
 	char *data;
@@ -708,23 +731,22 @@ static int ping_send_one_ipv6 (pingobj_t *obj, pinghost_t *ph, int fd)
 
 	dprintf ("ph->hostname = %s\n", ph->hostname);
 
-	memset (buf, '\0', sizeof (buf));
 	icmp6 = (struct icmp6_hdr *) buf;
-	data  = (char *) (icmp6 + 1);
+	*icmp6 = (struct icmp6_hdr) {
+		.icmp6_type  = ICMP6_ECHO_REQUEST,
+		.icmp6_id    = htons (ph->ident),
+		.icmp6_seq   = htons (ph->sequence),
+	};
 
-	icmp6->icmp6_type  = ICMP6_ECHO_REQUEST;
-	icmp6->icmp6_code  = 0;
-	/* The checksum will be calculated by the TCP/IP stack.  */
-	/* FIXME */
-	icmp6->icmp6_cksum = 0;
-	icmp6->icmp6_id    = htons (ph->ident);
-	icmp6->icmp6_seq   = htons (ph->sequence);
+	datalen = strlen (ph->data);
+	buflen = sizeof (*icmp6) + datalen;
+	if (sizeof (buf) < buflen)
+		return (EINVAL);
 
-	buflen = 4096 - sizeof (struct icmp6_hdr);
-	strncpy (data, ph->data, buflen);
-	datalen = strlen (data);
+	data  = buf + ICMP_MINLEN;
+	memcpy (data, ph->data, datalen);
 
-	buflen = datalen + sizeof (struct icmp6_hdr);
+	/* The checksum will be calculated by the TCP/IP stack. */
 
 	dprintf ("Sending ICMPv6 package with ID 0x%04x\n", ph->ident);
 
@@ -903,7 +925,7 @@ static int ping_get_ident (void)
 	retval = (int) random ();
 
 	dprintf ("Random number: %#x\n", retval);
-	
+
 	return (retval);
 }
 
@@ -935,18 +957,19 @@ static pinghost_t *ping_alloc (void)
 
 static void ping_free (pinghost_t *ph)
 {
-	if (ph->username != NULL)
-		free (ph->username);
-
-	if (ph->hostname != NULL)
-		free (ph->hostname);
+	if (ph == NULL)
+		return;
 
-	if (ph->data != NULL)
-		free (ph->data);
+	free (ph->username);
+	free (ph->hostname);
+	free (ph->data);
 
 	free (ph);
 }
 
+/* ping_open_socket opens, initializes and returns a new raw socket to use for
+ * ICMPv4 or ICMPv6 packets. addrfam must be either AF_INET or AF_INET6. On
+ * error, -1 is returned and obj->errmsg is set appropriately. */
 static int ping_open_socket(pingobj_t *obj, int addrfam)
 {
 	int fd;
@@ -960,18 +983,28 @@ static int ping_open_socket(pingobj_t *obj, int addrfam)
 	}
 	else /* this should not happen */
 	{
+		ping_set_error (obj, "ping_open_socket", "Unknown address family");
 		dprintf ("Unknown address family: %i\n", addrfam);
-		return (-1);
+		return -1;
 	}
 
 	if (fd == -1)
 	{
+		ping_set_errno (obj, errno);
 #if WITH_DEBUG
 		char errbuf[PING_ERRMSG_LEN];
 		dprintf ("socket: %s\n",
 				sstrerror (errno, errbuf, sizeof (errbuf)));
 #endif
-		ping_set_errno (obj, errno);
+		return -1;
+	}
+	else if (fd >= FD_SETSIZE)
+	{
+		ping_set_errno (obj, EMFILE);
+		dprintf ("socket(2) returned file descriptor %d, which is above the file "
+			 "descriptor limit for select(2) (FD_SETSIZE = %d)\n",
+			 fd, FD_SETSIZE);
+		close (fd);
 		return -1;
 	}
 
@@ -982,12 +1015,12 @@ static int ping_open_socket(pingobj_t *obj, int addrfam)
 
 		if (bind (fd, obj->srcaddr, obj->srcaddrlen) == -1)
 		{
+			ping_set_errno (obj, errno);
 #if WITH_DEBUG
 			char errbuf[PING_ERRMSG_LEN];
 			dprintf ("bind: %s\n",
 					sstrerror (errno, errbuf, sizeof (errbuf)));
 #endif
-			ping_set_errno (obj, errno);
 			close (fd);
 			return -1;
 		}
@@ -999,34 +1032,47 @@ static int ping_open_socket(pingobj_t *obj, int addrfam)
 		if (setsockopt (fd, SOL_SOCKET, SO_BINDTODEVICE,
 				obj->device, strlen (obj->device) + 1) != 0)
 		{
+			ping_set_errno (obj, errno);
 #if WITH_DEBUG
 			char errbuf[PING_ERRMSG_LEN];
 			dprintf ("setsockopt (SO_BINDTODEVICE): %s\n",
 					sstrerror (errno, errbuf, sizeof (errbuf)));
 #endif
-			ping_set_errno (obj, errno);
 			close (fd);
 			return -1;
 		}
 	}
 #endif /* SO_BINDTODEVICE */
+#ifdef SO_MARK
+	if (obj->set_mark)
+	{
+		if (setsockopt(fd, SOL_SOCKET, SO_MARK,
+				&obj->mark, sizeof(obj->mark)) != 0)
+		{
+			ping_set_errno (obj, errno);
+#if WITH_DEBUG
+			char errbuf[PING_ERRMSG_LEN];
+			dprintf ("setsockopt (SO_MARK): %s\n",
+				 sstrerror (errno, errbuf, sizeof (errbuf)));
+#endif
+			close (fd);
+			return -1;
+		}
+	}
+#endif
 #ifdef SO_TIMESTAMP
 	if (1) /* {{{ */
 	{
-		int status;
-		int opt = 1;
-
-		status = setsockopt (fd,
-				SOL_SOCKET, SO_TIMESTAMP,
-				&opt, sizeof (opt));
+		int status = setsockopt (fd, SOL_SOCKET, SO_TIMESTAMP,
+		                         &(int){1}, sizeof(int));
 		if (status != 0)
 		{
+			ping_set_errno (obj, errno);
 #if WITH_DEBUG
 			char errbuf[PING_ERRMSG_LEN];
 			dprintf ("setsockopt (SO_TIMESTAMP): %s\n",
 					sstrerror (errno, errbuf, sizeof (errbuf)));
 #endif
-			ping_set_errno (obj, errno);
 			close (fd);
 			return -1;
 		}
@@ -1035,35 +1081,27 @@ static int ping_open_socket(pingobj_t *obj, int addrfam)
 
 	if (addrfam == AF_INET)
 	{
-		int opt;
-
+#ifdef IP_RECVTOS
 		/* Enable receiving the TOS field */
-		opt = 1;
-		setsockopt (fd, IPPROTO_IP, IP_RECVTOS,
-				&opt, sizeof (opt));
+		setsockopt (fd, IPPROTO_IP, IP_RECVTOS, &(int){1}, sizeof(int));
+#endif /* IP_RECVTOS */
 
 		/* Enable receiving the TTL field */
-		opt = 1;
-		setsockopt (fd, IPPROTO_IP, IP_RECVTTL,
-				&opt, sizeof (opt));
+		setsockopt (fd, IPPROTO_IP, IP_RECVTTL, &(int){1}, sizeof(int));
 	}
 #if defined(IPV6_RECVHOPLIMIT) || defined(IPV6_RECVTCLASS)
 	else if (addrfam == AF_INET6)
 	{
-		int opt;
-
 # if defined(IPV6_RECVHOPLIMIT)
 		/* For details see RFC 3542, section 6.3. */
-		opt = 1;
 		setsockopt (fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT,
-				&opt, sizeof (opt));
+		            &(int){1}, sizeof(int));
 # endif /* IPV6_RECVHOPLIMIT */
 
 # if defined(IPV6_RECVTCLASS)
 		/* For details see RFC 3542, section 6.5. */
-		opt = 1;
 		setsockopt (fd, IPPROTO_IPV6, IPV6_RECVTCLASS,
-				&opt, sizeof (opt));
+		            &(int){1}, sizeof(int));
 # endif /* IPV6_RECVTCLASS */
 	}
 #endif /* IPV6_RECVHOPLIMIT || IPV6_RECVTCLASS */
@@ -1085,9 +1123,9 @@ pingobj_t *ping_construct (void)
 {
 	pingobj_t *obj;
 
-	if ((obj = (pingobj_t *) malloc (sizeof (pingobj_t))) == NULL)
+	if ((obj = malloc (sizeof (*obj))) == NULL)
 		return (NULL);
-	memset (obj, 0, sizeof (pingobj_t));
+	memset (obj, 0, sizeof (*obj));
 
 	obj->timeout    = PING_DEF_TIMEOUT;
 	obj->ttl        = PING_DEF_TTL;
@@ -1103,29 +1141,22 @@ pingobj_t *ping_construct (void)
 void ping_destroy (pingobj_t *obj)
 {
 	pinghost_t *current;
-	pinghost_t *next;
 
 	if (obj == NULL)
 		return;
 
 	current = obj->head;
-	next = NULL;
 
 	while (current != NULL)
 	{
-		next = current->next;
+		pinghost_t *next = current->next;
 		ping_free (current);
 		current = next;
 	}
 
-	if (obj->data != NULL)
-		free (obj->data);
-
-	if (obj->srcaddr != NULL)
-		free (obj->srcaddr);
-
-	if (obj->device != NULL)
-		free (obj->device);
+	free (obj->data);
+	free (obj->srcaddr);
+	free (obj->device);
 
 	if (obj->fd4 != -1)
 		close(obj->fd4);
@@ -1285,6 +1316,19 @@ int ping_setopt (pingobj_t *obj, int option, void *value)
 		} /* case PING_OPT_DEVICE */
 		break;
 
+		case PING_OPT_MARK:
+		{
+#ifdef SO_MARK
+			obj->mark     = *(int*)(value);
+			obj->set_mark = 1;
+#else /* SO_MARK */
+			ping_set_errno (obj, ENOTSUP);
+			ret = -1;
+#endif /* !SO_MARK */
+
+		} /* case PING_OPT_MARK */
+		break;
+
 		default:
 			ret = -2;
 	} /* switch (option) */
@@ -1294,66 +1338,49 @@ int ping_setopt (pingobj_t *obj, int option, void *value)
 
 int ping_send (pingobj_t *obj)
 {
-	fd_set read_fds;
-	fd_set write_fds;
-	fd_set err_fds;
-
-	int num_fds;
-	int max_fd;
-
-	pinghost_t *ph;
 	pinghost_t *ptr;
 
 	struct timeval endtime;
 	struct timeval nowtime;
 	struct timeval timeout;
-	int status;
-
-	int pings = 0;
-	int ret = 0;
 
-	ph = obj->head;
+	_Bool need_ipv4_socket = 0;
+	_Bool need_ipv6_socket = 0;
 
-	int fd4 = obj->fd4;
-	int fd6 = obj->fd6;
-
-	for (ptr = ph; ptr != NULL; ptr = ptr->next)
+	for (ptr = obj->head; ptr != NULL; ptr = ptr->next)
 	{
-		if (fd6 == -1 && ptr->addrfamily == AF_INET6)
-		{
-			obj->fd6 = fd6 = ping_open_socket(obj, AF_INET6);
-			ping_set_ttl (obj, obj->ttl);
-			ping_set_qos (obj, obj->qos);
-		}
-		else if (fd4 == -1 && ptr->addrfamily == AF_INET)
-		{
-			obj->fd4 = fd4 = ping_open_socket(obj, AF_INET);
-			ping_set_ttl (obj, obj->ttl);
-			ping_set_qos (obj, obj->qos);
-		}
-
-		if ((fd6 == -1 && ptr->addrfamily == AF_INET6)
-			|| (fd4 == -1 && ptr->addrfamily == AF_INET))
-		{
-#if WITH_DEBUG
-			char errbuf[PING_ERRMSG_LEN];
-			dprintf ("socket: %s\n",
-					sstrerror (errno, errbuf, sizeof (errbuf)));
-#endif
-			ping_set_errno (obj, errno);
-			return (-1);
-		}
-
 		ptr->latency  = -1.0;
 		ptr->recv_ttl = -1;
+
+		if (ptr->addrfamily == AF_INET)
+			need_ipv4_socket = 1;
+		else if (ptr->addrfamily == AF_INET6)
+			need_ipv6_socket = 1;
 	}
 
-	if (fd4 == -1 && fd6 == -1)
+	if (!need_ipv4_socket && !need_ipv6_socket)
 	{
-		dprintf("No sockets to use\n");
+		ping_set_error (obj, "ping_send", "No hosts to ping");
 		return (-1);
 	}
 
+	if (need_ipv4_socket && obj->fd4 == -1)
+	{
+		obj->fd4 = ping_open_socket(obj, AF_INET);
+		if (obj->fd4 == -1)
+			return (-1);
+		ping_set_ttl (obj, obj->ttl);
+		ping_set_qos (obj, obj->qos);
+	}
+	if (need_ipv6_socket && obj->fd6 == -1)
+	{
+		obj->fd6 = ping_open_socket(obj, AF_INET6);
+		if (obj->fd6 == -1)
+			return (-1);
+		ping_set_ttl (obj, obj->ttl);
+		ping_set_qos (obj, obj->qos);
+	}
+
 	if (gettimeofday (&nowtime, NULL) == -1)
 	{
 		ping_set_errno (obj, errno);
@@ -1370,27 +1397,58 @@ int ping_send (pingobj_t *obj)
 
 	ping_timeval_add (&nowtime, &timeout, &endtime);
 
-	ptr = ph;
-	num_fds = 0;
-	if (fd4 != -1) num_fds++;
-	if (fd6 != -1) num_fds++;
-	max_fd = fd4 > fd6 ? fd4 : fd6;
+	/* host_to_ping points to the host to which to send the next ping. The
+	 * pointer is advanced to the next host in the linked list after the
+	 * ping has been sent. If host_to_ping is NULL, no more pings need to be
+	 * send out. */
+	pinghost_t *host_to_ping = obj->head;
+
+	/* pings_in_flight is the number of hosts we sent a "ping" to but didn't
+	 * receive a "pong" yet. */
+	int pings_in_flight = 0;
 
-	while (pings > 0 || ptr != NULL)
+	/* pongs_received is the number of echo replies received. Unless there
+	 * is an error, this is used as the return value of ping_send(). */
+	int pongs_received = 0;
+
+	int error_count = 0;
+
+	while (pings_in_flight > 0 || host_to_ping != NULL)
 	{
+		fd_set read_fds;
+		fd_set write_fds;
+
+		int write_fd = -1;
+		int max_fd = -1;
+
 		FD_ZERO (&read_fds);
 		FD_ZERO (&write_fds);
-		FD_ZERO (&err_fds);
 
-		if (fd4 != -1) FD_SET(fd4, &read_fds);
-		if (fd6 != -1) FD_SET(fd6, &read_fds);
+		if (obj->fd4 != -1)
+		{
+			FD_SET(obj->fd4, &read_fds);
+			if (host_to_ping != NULL && host_to_ping->addrfamily == AF_INET)
+				write_fd = obj->fd4;
+
+			if (max_fd < obj->fd4)
+				max_fd = obj->fd4;
+		}
 
-		if (fd4 != -1 && ptr != NULL && ptr->addrfamily == AF_INET)
-			FD_SET(fd4, &write_fds);
-		if (fd6 != -1 && ptr != NULL && ptr->addrfamily == AF_INET6)
-			FD_SET(fd6, &write_fds);
-		if (fd4 != -1) FD_SET(fd4, &err_fds);
-		if (fd6 != -1) FD_SET(fd6, &err_fds);
+		if (obj->fd6 != -1)
+		{
+			FD_SET(obj->fd6, &read_fds);
+			if (host_to_ping != NULL && host_to_ping->addrfamily == AF_INET6)
+				write_fd = obj->fd6;
+
+			if (max_fd < obj->fd6)
+				max_fd = obj->fd6;
+		}
+
+		if (write_fd != -1)
+			FD_SET(write_fd, &write_fds);
+
+		assert (max_fd != -1);
+		assert (max_fd < FD_SETSIZE);
 
 		if (gettimeofday (&nowtime, NULL) == -1)
 		{
@@ -1401,11 +1459,12 @@ int ping_send (pingobj_t *obj)
 		if (ping_timeval_sub (&endtime, &nowtime, &timeout) == -1)
 			break;
 
-		dprintf ("Waiting on %i sockets for %i.%06i seconds\n", num_fds,
-				(int) timeout.tv_sec,
-				(int) timeout.tv_usec);
+		dprintf ("Waiting on %i sockets for %u.%06u seconds\n",
+				((obj->fd4 != -1) ? 1 : 0) + ((obj->fd6 != -1) ? 1 : 0),
+				(unsigned) timeout.tv_sec,
+				(unsigned) timeout.tv_usec);
 
-		status = select (max_fd + 1, &read_fds, &write_fds, &err_fds, &timeout);
+		int status = select (max_fd + 1, &read_fds, &write_fds, NULL, &timeout);
 
 		if (gettimeofday (&nowtime, NULL) == -1)
 		{
@@ -1413,78 +1472,63 @@ int ping_send (pingobj_t *obj)
 			return (-1);
 		}
 
-		if ((status == -1) && (errno == EINTR))
-		{
-			dprintf ("select was interrupted by signal..\n");
-			continue;
-		}
-		else if (status < 0)
+		if (status == -1)
 		{
-#if WITH_DEBUG
-			char errbuf[PING_ERRMSG_LEN];
-			dprintf ("select: %s\n",
-					sstrerror (errno, errbuf, sizeof (errbuf)));
-#endif
-			break;
+			ping_set_errno (obj, errno);
+			dprintf ("select: %s\n", obj->errmsg);
+			return (-1);
 		}
 		else if (status == 0)
 		{
 			dprintf ("select timed out\n");
-			for (ptr = ph; ptr != NULL; ptr = ptr->next)
-				if (ptr->latency < 0.0)
-					ptr->dropped++;
-			
+
+			pinghost_t *ph;
+			for (ph = obj->head; ph != NULL; ph = ph->next)
+				if (ph->latency < 0.0)
+					ph->dropped++;
 			break;
 		}
 
-		if (fd4 != -1)
+		/* first, check if we can receive a reply ... */
+		if (obj->fd6  != -1 && FD_ISSET (obj->fd6, &read_fds))
 		{
-			if (FD_ISSET (fd4, &read_fds))
+			if (ping_receive_one (obj, &nowtime, AF_INET6) == 0)
 			{
-				if (!ping_receive_one(obj, &nowtime, AF_INET))
-					--pings;
+				pings_in_flight--;
+				pongs_received++;
 			}
-			else if (ptr != NULL && ptr->addrfamily == AF_INET && 
-						FD_ISSET (fd4, &write_fds))
-			{
-				if (!ping_send_one(obj, ptr, fd4))
-				{
-					ptr = ptr->next;
-					++pings;
-				}
-				else
-				{
-					--ret;
-				}
-			}
-
+			continue;
 		}
-
-		if (fd6  != -1)
+		if (obj->fd4 != -1 && FD_ISSET (obj->fd4, &read_fds))
 		{
-			if (FD_ISSET (fd6, &read_fds))
+			if (ping_receive_one (obj, &nowtime, AF_INET) == 0)
 			{
-				if (!ping_receive_one(obj, &nowtime, AF_INET6))
-					--pings;
-			}
-			else if (ptr != NULL && ptr->addrfamily == AF_INET6 &&
-						FD_ISSET (fd6, &write_fds))
-			{
-				if (!ping_send_one(obj, ptr, fd6))
-				{
-					++pings;
-					ptr = ptr->next;
-				}
-				else
-				{
-					--ret;
-				}
+				pings_in_flight--;
+				pongs_received++;
 			}
+			continue;
 		}
 
+		/* ... and if no reply is available to read, continue sending
+		 * out pings. */
+
+		/* this condition should always be true. We keep it for
+		 * consistency with the read blocks above and just to be on the
+		 * safe side. */
+		if (write_fd != -1 && FD_ISSET (write_fd, &write_fds))
+		{
+			if (ping_send_one (obj, host_to_ping, write_fd) == 0)
+				pings_in_flight++;
+			else
+				error_count++;
+			host_to_ping = host_to_ping->next;
+			continue;
+		}
 	} /* while (1) */
 
-	return (ret);
+	if (error_count)
+		return (-1 * error_count);
+	return (pongs_received);
 } /* int ping_send */
 
 static pinghost_t *ping_host_search (pinghost_t *ph, const char *host)
@@ -1628,7 +1672,6 @@ int ping_host_add (pingobj_t *obj, const char *host)
 			}
 		}
 #endif /* AI_CANONNAME */
-
 	} /* for (ai_ptr = ai_list; ai_ptr != NULL; ai_ptr = ai_ptr->ai_next) */
 
 	freeaddrinfo (ai_list);
@@ -1689,10 +1732,10 @@ int ping_host_remove (pingobj_t *obj, const char *host)
 		obj->head = cur->next;
 	else
 		pre->next = cur->next;
-	
+
 	target = cur;
 	pre = NULL;
-	
+
 	cur = obj->table[target->ident % PING_TABLE_LEN];
 
 	while (cur != NULL)
@@ -1735,6 +1778,20 @@ pingobj_iter_t *ping_iterator_next (pingobj_iter_t *iter)
 	return ((pingobj_iter_t *) iter->next);
 }
 
+int ping_iterator_count (pingobj_t *obj)
+{
+	if (obj == NULL)
+		return 0;
+
+	int count = 0;
+	pingobj_iter_t *iter = obj->head;
+	while (iter) {
+		count++;
+		iter = iter->next;
+	}
+	return count;
+}
+
 int ping_iterator_get_info (pingobj_iter_t *iter, int info,
 		void *buffer, size_t *buffer_len)
 {