wget: use monotonic_sec instead of gettimeofday

zcip: use monotonic_us instead of gettimeofday
udhcpcd: simpler, shorter random_xid()

function                                             old     new   delta
monotonic_sec                                          -      41     +41
find_pair                                            164     180     +16
run_list_real                                       2018    2028     +10
cmp_main                                             547     555      +8
collect_ctx                                          112     119      +7
singlemount                                         4544    4549      +5
time_main                                           1124    1128      +4
static.start_sec                                       -       4      +4
static.lastupdate_sec                                  -       4      +4
sock                                                   -       4      +4
read_package_field                                   253     257      +4
pick                                                  38      40      +2
get_next_line                                        145     147      +2
count_lines                                           59      61      +2
process_stdin                                        435     433      -2
xstrtoul_range_sfx                                   229     226      -3
static.initialized                                     4       1      -3
dhcprelay_main                                      1125    1122      -3
catcher                                              380     377      -3
arping_main                                         1969    1966      -3
s                                                      8       4      -4
cfg                                                    4       -      -4
static.lastupdate                                      8       -      -8
start                                                  8       -      -8
random_xid                                            95      33     -62
.rodata                                           129114  129050     -64
zcip_main                                           1731    1576    -155
progressmeter                                       1035     867    -168
------------------------------------------------------------------------------
(add/remove: 4/3 grow/shrink: 10/11 up/down: 113/-490)       Total: -377 bytes

8 files changed, 151 insertions, 144 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 2a50bce66..3c9f9fe81 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -201,6 +201,7 @@ struct sysinfo {
 int sysinfo(struct sysinfo* info);
 
 unsigned long long monotonic_us(void);
+unsigned monotonic_sec(void);
 
 extern void chomp(char *s);
 extern void trim(char *s);
diff --git a/libbb/time.c b/libbb/time.c
index f2a741521..3e35542f3 100644
--- a/libbb/time.c
+++ b/libbb/time.c
@@ -21,12 +21,23 @@ unsigned long long monotonic_us(void)
 		bb_error_msg_and_die("clock_gettime(MONOTONIC) failed");
 	return ts.tv_sec * 1000000ULL + ts.tv_nsec/1000;
 }
+unsigned monotonic_sec(void)
+{
+	struct timespec ts;
+	if (syscall(__NR_clock_gettime, CLOCK_MONOTONIC, &ts))
+		bb_error_msg_and_die("clock_gettime(MONOTONIC) failed");
+	return ts.tv_sec;
+}
 #else
 unsigned long long monotonic_us(void)
 {
 	struct timeval tv;
-	if (gettimeofday(&tv, NULL))
-		bb_error_msg_and_die("gettimeofday failed");
+	gettimeofday(&tv, NULL);
 	return tv.tv_sec * 1000000ULL + tv_usec;
 }
+
+unsigned monotonic_sec(void)
+{
+	return time(NULL);
+}
 #endif
diff --git a/miscutils/time.c b/miscutils/time.c
index 578cb35ff..9b7db662a 100644
--- a/miscutils/time.c
+++ b/miscutils/time.c
@@ -180,7 +180,12 @@ static void summarize(const char *fmt, char **command, resource_t * resp)
 	vv_ms = (resp->ru.ru_utime.tv_sec + resp->ru.ru_stime.tv_sec) * 1000
 	      + (resp->ru.ru_utime.tv_usec + resp->ru.ru_stime.tv_usec) / 1000;
 
-	cpu_ticks = vv_ms * TICKS_PER_SEC / 1000;
+#if (1000 / TICKS_PER_SEC) * TICKS_PER_SEC == 1000
+	/* 1000 is exactly divisible by TICKS_PER_SEC */
+	cpu_ticks = vv_ms / (1000 / TICKS_PER_SEC);
+#else
+	cpu_ticks = vv_ms * (unsigned long long)TICKS_PER_SEC / 1000;
+#endif
 	if (!cpu_ticks) cpu_ticks = 1; /* we divide by it, must be nonzero */
 
 	/* putchar() != putc(stdout) in glibc! */
diff --git a/networking/arping.c b/networking/arping.c
index a022e70ea..7a9fbc2f4 100644
--- a/networking/arping.c
+++ b/networking/arping.c
@@ -33,18 +33,17 @@ enum {
 	BCAST_ONLY = 32,
 	UNICASTING = 64
 };
-static int cfg;
 
-static int s;
+static int sock;
 static unsigned count = UINT_MAX;
 static unsigned timeout_us;
-static int sent;
-static int brd_sent;
-static int received;
-static int brd_recv;
-static int req_recv;
+static unsigned sent;
+static unsigned brd_sent;
+static unsigned received;
+static unsigned brd_recv;
+static unsigned req_recv;
 
-static int send_pack(int sock, struct in_addr *src_addr,
+static int send_pack(struct in_addr *src_addr,
 			struct in_addr *dst_addr, struct sockaddr_ll *ME,
 			struct sockaddr_ll *HE)
 {
@@ -59,7 +58,7 @@ static int send_pack(int sock, struct in_addr *src_addr,
 	ah->ar_pro = htons(ETH_P_IP);
 	ah->ar_hln = ME->sll_halen;
 	ah->ar_pln = 4;
-	ah->ar_op = cfg & ADVERT ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
+	ah->ar_op = option_mask32 & ADVERT ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
 
 	memcpy(p, &ME->sll_addr, ah->ar_hln);
 	p += ME->sll_halen;
@@ -67,7 +66,7 @@ static int send_pack(int sock, struct in_addr *src_addr,
 	memcpy(p, src_addr, 4);
 	p += 4;
 
-	if (cfg & ADVERT)
+	if (option_mask32 & ADVERT)
 		memcpy(p, &ME->sll_addr, ah->ar_hln);
 	else
 		memcpy(p, &HE->sll_addr, ah->ar_hln);
@@ -81,7 +80,7 @@ static int send_pack(int sock, struct in_addr *src_addr,
 	if (err == p - buf) {
 		last = now;
 		sent++;
-		if (!(cfg & UNICASTING))
+		if (!(option_mask32 & UNICASTING))
 			brd_sent++;
 	}
 	return err;
@@ -90,17 +89,17 @@ static int send_pack(int sock, struct in_addr *src_addr,
 static void finish(void) ATTRIBUTE_NORETURN;
 static void finish(void)
 {
-	if (!(cfg & QUIET)) {
-		printf("Sent %d probe(s) (%d broadcast(s))\n"
-			"Received %d repl%s"
-			" (%d request(s), %d broadcast(s))\n",
+	if (!(option_mask32 & QUIET)) {
+		printf("Sent %u probe(s) (%u broadcast(s))\n"
+			"Received %u repl%s"
+			" (%u request(s), %u broadcast(s))\n",
 			sent, brd_sent,
 			received, (received == 1) ? "ies" : "y",
 			req_recv, brd_recv);
 	}
-	if (cfg & DAD)
+	if (option_mask32 & DAD)
 		exit(!!received);
-	if (cfg & UNSOLICITED)
+	if (option_mask32 & UNSOLICITED)
 		exit(0);
 	exit(!received);
 }
@@ -121,8 +120,8 @@ static void catcher(void)
 	count--;
 
 	if (last == 0 || (now - last) > 500000) {
-		send_pack(s, &src, &dst, &me, &he);
-		if (count == 0 && (cfg & UNSOLICITED))
+		send_pack(&src, &dst, &me, &he);
+		if (count == 0 && (option_mask32 & UNSOLICITED))
 			finish();
 	}
 	alarm(1);
@@ -160,7 +159,7 @@ static int recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
 		return 0;
 	memcpy(&src_ip, p + ah->ar_hln, 4);
 	memcpy(&dst_ip, p + ah->ar_hln + 4 + ah->ar_hln, 4);
-	if (!(cfg & DAD)) {
+	if (!(option_mask32 & DAD)) {
 		if (src_ip.s_addr != dst.s_addr)
 			return 0;
 		if (src.s_addr != dst_ip.s_addr)
@@ -188,7 +187,7 @@ static int recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
 		if (src.s_addr && src.s_addr != dst_ip.s_addr)
 			return 0;
 	}
-	if (!(cfg & QUIET)) {
+	if (!(option_mask32 & QUIET)) {
 		int s_printed = 0;
 
 		printf("%scast re%s from %s [%s]",
@@ -219,11 +218,11 @@ static int recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
 		brd_recv++;
 	if (ah->ar_op == htons(ARPOP_REQUEST))
 		req_recv++;
-	if (cfg & QUIT_ON_REPLY)
+	if (option_mask32 & QUIT_ON_REPLY)
 		finish();
-	if (!(cfg & BCAST_ONLY)) {
+	if (!(option_mask32 & BCAST_ONLY)) {
 		memcpy(he.sll_addr, p, me.sll_halen);
-		cfg |= UNICASTING;
+		option_mask32 |= UNICASTING;
 	}
 	return 1;
 }
@@ -237,32 +236,32 @@ int arping_main(int argc, char **argv)
 	char *target;
 	unsigned char *packet;
 
-	s = xsocket(PF_PACKET, SOCK_DGRAM, 0);
+	sock = xsocket(PF_PACKET, SOCK_DGRAM, 0);
 
 	// Drop suid root privileges
 	xsetuid(getuid());
 
 	{
 		unsigned opt;
-		char *_count, *_timeout;
+		char *str_count, *str_timeout;
 
 		/* Dad also sets quit_on_reply.
 		 * Advert also sets unsolicited.
 		 */
 		opt_complementary = "=1:Df:AU";
 		opt = getopt32(argc, argv, "DUAqfbc:w:I:s:",
-					&_count, &_timeout, &device, &source);
-		cfg |= opt & 0x3f; /* set respective flags */
+				&str_count, &str_timeout, &device, &source);
 		if (opt & 0x40) /* -c: count */
-			count = xatou(_count);
+			count = xatou(str_count);
 		if (opt & 0x80) /* -w: timeout */
-			timeout_us = xatou_range(_timeout, 0, INT_MAX/2000000) * 1000000;
+			timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000;
 		//if (opt & 0x100) /* -I: interface */
 		if (strlen(device) >= IF_NAMESIZE) {
 			bb_error_msg_and_die("interface name '%s' is too long",
 							device);
 		}
 		//if (opt & 0x200) /* -s: source */
+		option_mask32 &= 0x3f; /* set respective flags */
 	}
 
 	target = argv[optind];
@@ -274,12 +273,12 @@ int arping_main(int argc, char **argv)
 
 		memset(&ifr, 0, sizeof(ifr));
 		strncpy(ifr.ifr_name, device, IFNAMSIZ - 1);
-		if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
+		if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0) {
 			bb_error_msg_and_die("interface %s not found", device);
 		}
 		ifindex = ifr.ifr_ifindex;
 
-		if (ioctl(s, SIOCGIFFLAGS, (char *) &ifr)) {
+		if (ioctl(sock, SIOCGIFFLAGS, (char *) &ifr)) {
 			bb_error_msg_and_die("SIOCGIFFLAGS");
 		}
 		if (!(ifr.ifr_flags & IFF_UP)) {
@@ -287,7 +286,7 @@ int arping_main(int argc, char **argv)
 		}
 		if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
 			bb_error_msg("interface %s is not ARPable", device);
-			return (cfg & DAD ? 0 : 2);
+			return (option_mask32 & DAD ? 0 : 2);
 		}
 	}
 
@@ -303,10 +302,10 @@ int arping_main(int argc, char **argv)
 		bb_error_msg_and_die("invalid source address %s", source);
 	}
 
-	if (!(cfg & DAD) && (cfg & UNSOLICITED) && src.s_addr == 0)
+	if (!(option_mask32 & DAD) && (option_mask32 & UNSOLICITED) && src.s_addr == 0)
 		src = dst;
 
-	if (!(cfg & DAD) || src.s_addr) {
+	if (!(option_mask32 & DAD) || src.s_addr) {
 		struct sockaddr_in saddr;
 		int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0);
 
@@ -319,7 +318,7 @@ int arping_main(int argc, char **argv)
 		if (src.s_addr) {
 			saddr.sin_addr = src;
 			xbind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
-		} else if (!(cfg & DAD)) {
+		} else if (!(option_mask32 & DAD)) {
 			socklen_t alen = sizeof(saddr);
 
 			saddr.sin_port = htons(1025);
@@ -339,29 +338,29 @@ int arping_main(int argc, char **argv)
 	me.sll_family = AF_PACKET;
 	me.sll_ifindex = ifindex;
 	me.sll_protocol = htons(ETH_P_ARP);
-	xbind(s, (struct sockaddr *) &me, sizeof(me));
+	xbind(sock, (struct sockaddr *) &me, sizeof(me));
 
 	{
 		socklen_t alen = sizeof(me);
 
-		if (getsockname(s, (struct sockaddr *) &me, &alen) == -1) {
+		if (getsockname(sock, (struct sockaddr *) &me, &alen) == -1) {
 			bb_error_msg_and_die("getsockname");
 		}
 	}
 	if (me.sll_halen == 0) {
 		bb_error_msg("interface \"%s\" is not ARPable (no ll address)", device);
-		return (cfg & DAD ? 0 : 2);
+		return (option_mask32 & DAD ? 0 : 2);
 	}
 	he = me;
 	memset(he.sll_addr, -1, he.sll_halen);
 
-	if (!(cfg & QUIET)) {
+	if (!(option_mask32 & QUIET)) {
 		printf("ARPING to %s from %s via %s\n",
 			inet_ntoa(dst), inet_ntoa(src),
 			device ? device : "unknown");
 	}
 
-	if (!src.s_addr && !(cfg & DAD)) {
+	if (!src.s_addr && !(option_mask32 & DAD)) {
 		bb_error_msg_and_die("no src address in the non-DAD mode");
 	}
 
@@ -387,7 +386,7 @@ int arping_main(int argc, char **argv)
 		socklen_t alen = sizeof(from);
 		int cc;
 
-		cc = recvfrom(s, packet, 4096, 0, (struct sockaddr *) &from, &alen);
+		cc = recvfrom(sock, packet, 4096, 0, (struct sockaddr *) &from, &alen);
 		if (cc < 0) {
 			bb_perror_msg("recvfrom");
 			continue;
diff --git a/networking/udhcp/clientpacket.c b/networking/udhcp/clientpacket.c
index 69d7f2d38..af97962a0 100644
--- a/networking/udhcp/clientpacket.c
+++ b/networking/udhcp/clientpacket.c
@@ -25,19 +25,13 @@
 
 
 /* Create a random xid */
-unsigned long random_xid(void)
+unsigned random_xid(void)
 {
-	static int initialized;
+	static smallint initialized;
+
 	if (!initialized) {
-		unsigned long seed;
-
-		if (open_read_close("/dev/urandom", &seed, sizeof(seed)) < 0) {
-			bb_info_msg("Cannot load seed "
-				"from /dev/urandom: %s", strerror(errno));
-			seed = time(0);
-		}
-		srand(seed);
-		initialized++;
+		srand(monotonic_us());
+		initialized = 1;
 	}
 	return rand();
 }
diff --git a/networking/udhcp/dhcpc.h b/networking/udhcp/dhcpc.h
index 4ddd12120..fa091bf72 100644
--- a/networking/udhcp/dhcpc.h
+++ b/networking/udhcp/dhcpc.h
@@ -38,7 +38,7 @@ extern struct client_config_t client_config;
 
 /*** clientpacket.h ***/
 
-unsigned long random_xid(void);
+unsigned random_xid(void);
 int send_discover(unsigned long xid, unsigned long requested);
 int send_selecting(unsigned long xid, unsigned long server, unsigned long requested);
 int send_renew(unsigned long xid, unsigned long server, unsigned long ciaddr);
diff --git a/networking/wget.c b/networking/wget.c
index fc7f7c32c..8be37a744 100644
--- a/networking/wget.c
+++ b/networking/wget.c
@@ -38,7 +38,6 @@ static bool chunked;                     /* chunked transfer encoding */
 #if ENABLE_FEATURE_WGET_STATUSBAR
 static void progressmeter(int flag);
 static const char *curfile;             /* Name of current file being transferred */
-static struct timeval start;            /* Time a transfer started */
 enum {
 	STALLTIME = 5                   /* Seconds when xfer considered "stalled" */
 };
@@ -683,30 +682,30 @@ static void alarmtimer(int iwait)
 	setitimer(ITIMER_REAL, &itv, NULL);
 }
 
-
 static void
 progressmeter(int flag)
 {
-	static struct timeval lastupdate;
+	static unsigned lastupdate_sec;
+	static unsigned start_sec;
 	static off_t lastsize, totalsize;
 
-	struct timeval now, td, tvwait;
 	off_t abbrevsize;
-	int elapsed, ratio, barlength, i;
+	unsigned since_last_update, elapsed;
+	unsigned ratio;
+	int barlength, i;
 
 	if (flag == -1) { /* first call to progressmeter */
-		gettimeofday(&start, NULL);
-		lastupdate = start;
+		start_sec = monotonic_sec();
+		lastupdate_sec = start_sec;
 		lastsize = 0;
 		totalsize = content_len + beg_range; /* as content_len changes.. */
 	}
 
-	gettimeofday(&now, NULL);
 	ratio = 100;
 	if (totalsize != 0 && !chunked) {
-		/* long long helps to have working ETA even if !LFS */
-		ratio = (int) (100ULL * (transferred+beg_range) / totalsize);
-		ratio = MIN(ratio, 100);
+		/* long long helps to have it working even if !LFS */
+		ratio = (unsigned) (100ULL * (transferred+beg_range) / totalsize);
+		if (ratio > 100) ratio = 100;
 	}
 
 	fprintf(stderr, "\r%-20.20s%4d%% ", curfile, ratio);
@@ -714,12 +713,13 @@ progressmeter(int flag)
 	barlength = getttywidth() - 51;
 	if (barlength > 0) {
 		/* god bless gcc for variable arrays :) */
-		char buf[barlength+1];
 		i = barlength * ratio / 100;
-		memset(buf, '*', i);
-		memset(buf + i, ' ', barlength - i);
-		buf[barlength] = '\0';
-		fprintf(stderr, "|%s|", buf);
+		{
+			char buf[i+1];
+			memset(buf, '*', i);
+			buf[i] = '\0';
+			fprintf(stderr, "|%s%*s|", buf, barlength - i, "");
+		}
 	}
 	i = 0;
 	abbrevsize = transferred + beg_range;
@@ -730,22 +730,28 @@ progressmeter(int flag)
 	/* see http://en.wikipedia.org/wiki/Tera */
 	fprintf(stderr, "%6d %c%c ", (int)abbrevsize, " KMGTPEZY"[i], i?'B':' ');
 
-	timersub(&now, &lastupdate, &tvwait);
+// Nuts! Ain't it easier to update progress meter ONLY when we transferred++?
+// FIXME: get rid of alarmtimer + updateprogressmeter mess
+
+	elapsed = monotonic_sec();
+	since_last_update = elapsed - lastupdate_sec;
 	if (transferred > lastsize) {
-		lastupdate = now;
+		lastupdate_sec = elapsed;
 		lastsize = transferred;
-		if (tvwait.tv_sec >= STALLTIME)
-			timeradd(&start, &tvwait, &start);
-		tvwait.tv_sec = 0;
+		if (since_last_update >= STALLTIME) {
+			/* We "cut off" these seconds from elapsed time
+			 * by adjusting start time */
+			start_sec += since_last_update;
+		}
+		since_last_update = 0; /* we are un-stalled now */
 	}
-	timersub(&now, &start, &td);
-	elapsed = td.tv_sec;
+	elapsed -= start_sec; /* now it's "elapsed since start" */
 
-	if (tvwait.tv_sec >= STALLTIME) {
+	if (since_last_update >= STALLTIME) {
 		fprintf(stderr, " - stalled -");
 	} else {
 		off_t to_download = totalsize - beg_range;
-		if (transferred <= 0 || elapsed <= 0 || transferred > to_download || chunked) {
+		if (transferred <= 0 || (int)elapsed <= 0 || transferred > to_download || chunked) {
 			fprintf(stderr, "--:--:-- ETA");
 		} else {
 			/* to_download / (transferred/elapsed) - elapsed: */
diff --git a/networking/zcip.c b/networking/zcip.c
index eb0a7ba41..de4ee0b1a 100644
--- a/networking/zcip.c
+++ b/networking/zcip.c
@@ -23,7 +23,6 @@
 // - avoid silent script failures, especially under load...
 // - link status monitoring (restart on link-up; stop on link-down)
 
-#include "libbb.h"
 #include <syslog.h>
 #include <poll.h>
 #include <sys/wait.h>
@@ -31,10 +30,13 @@
 #include <net/ethernet.h>
 #include <net/if.h>
 #include <net/if_arp.h>
-
 #include <linux/if_packet.h>
 #include <linux/sockios.h>
 
+#include "libbb.h"
+
+/* We don't need more than 32 bits of the counter */
+#define MONOTONIC_US() ((unsigned)monotonic_us())
 
 struct arp_packet {
 	struct ether_header hdr;
@@ -78,15 +80,12 @@ static void pick(struct in_addr *ip)
 {
 	unsigned tmp;
 
-	/* use cheaper math than lrand48() mod N */
 	do {
-		tmp = (lrand48() >> 16) & IN_CLASSB_HOST;
+		tmp = rand() & IN_CLASSB_HOST;
 	} while (tmp > (IN_CLASSB_HOST - 0x0200));
 	ip->s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
 }
 
-/* TODO: we need a flag to direct bb_[p]error_msg output to stderr. */
-
 /**
  * Broadcast an ARP packet.
  */
@@ -151,7 +150,7 @@ static int run(char *argv[3], const char *intf, struct in_addr *ip)
  */
 static unsigned ALWAYS_INLINE ms_rdelay(unsigned secs)
 {
-	return lrand48() % (secs * 1000);
+	return rand() % (secs * 1000);
 }
 
 /**
@@ -176,29 +175,31 @@ int zcip_main(int argc, char **argv)
 		struct ifreq ifr;
 		char *intf;
 		char *script_av[3];
-		suseconds_t timeout; // milliseconds
+		int timeout_ms; /* must be signed */
 		unsigned conflicts;
 		unsigned nprobes;
 		unsigned nclaims;
 		int ready;
 		int verbose;
 	} L;
-#define null_ip   (L.null_ip  )
-#define null_addr (L.null_addr)
-#define saddr     (L.saddr    )
-#define ip        (L.ip       )
-#define ifr       (L.ifr      )
-#define intf      (L.intf     )
-#define script_av (L.script_av)
-#define timeout   (L.timeout  )
-#define conflicts (L.conflicts)
-#define nprobes   (L.nprobes  )
-#define nclaims   (L.nclaims  )
-#define ready     (L.ready    )
-#define verbose   (L.verbose  )
+#define null_ip    (L.null_ip   )
+#define null_addr  (L.null_addr )
+#define saddr      (L.saddr     )
+#define ip         (L.ip        )
+#define ifr        (L.ifr       )
+#define intf       (L.intf      )
+#define script_av  (L.script_av )
+#define timeout_ms (L.timeout_ms)
+#define conflicts  (L.conflicts )
+#define nprobes    (L.nprobes   )
+#define nclaims    (L.nclaims   )
+#define ready      (L.ready     )
+#define verbose    (L.verbose   )
 
 	memset(&L, 0, sizeof(L));
 
+	srand(MONOTONIC_US());
+
 #define FOREGROUND (opts & 1)
 #define QUIT       (opts & 2)
 	// parse commandline: prog [options] ifname script
@@ -282,7 +283,7 @@ int zcip_main(int argc, char **argv)
 	//  - defend it, within limits
 	while (1) {
 		struct pollfd fds[1];
-		struct timeval tv1;
+		unsigned deadline_us;
 		struct arp_packet p;
 
 		int source_ip_conflict = 0;
@@ -293,24 +294,18 @@ int zcip_main(int argc, char **argv)
 		fds[0].revents = 0;
 
 		// poll, being ready to adjust current timeout
-		if (!timeout) {
-			timeout = ms_rdelay(PROBE_WAIT);
+		if (!timeout_ms) {
+			timeout_ms = ms_rdelay(PROBE_WAIT);
 			// FIXME setsockopt(fd, SO_ATTACH_FILTER, ...) to
 			// make the kernel filter out all packets except
 			// ones we'd care about.
 		}
-		// set tv1 to the point in time when we timeout
-		gettimeofday(&tv1, NULL);
-		tv1.tv_usec += (timeout % 1000) * 1000;
-		while (tv1.tv_usec > 1000000) {
-			tv1.tv_usec -= 1000000;
-			tv1.tv_sec++;
-		}
-		tv1.tv_sec += timeout / 1000;
+		// set deadline_us to the point in time when we timeout
+		deadline_us = MONOTONIC_US() + timeout_ms * 1000;
 
-		VDBG("...wait %ld %s nprobes=%d, nclaims=%d\n",
-				timeout, intf, nprobes, nclaims);
-		switch (poll(fds, 1, timeout)) {
+		VDBG("...wait %d %s nprobes=%u, nclaims=%u\n",
+				timeout_ms, intf, nprobes, nclaims);
+		switch (poll(fds, 1, timeout_ms)) {
 
 		// timeout
 		case 0:
@@ -321,25 +316,24 @@ int zcip_main(int argc, char **argv)
 				// have been received, so we can progress through the states
 				if (nprobes < PROBE_NUM) {
 					nprobes++;
-					VDBG("probe/%d %s@%s\n",
+					VDBG("probe/%u %s@%s\n",
 							nprobes, intf, inet_ntoa(ip));
 					arp(fd, &saddr, ARPOP_REQUEST,
 							&eth_addr, null_ip,
 							&null_addr, ip);
-					timeout = PROBE_MIN * 1000;
-					timeout += ms_rdelay(PROBE_MAX
-							- PROBE_MIN);
+					timeout_ms = PROBE_MIN * 1000;
+					timeout_ms += ms_rdelay(PROBE_MAX - PROBE_MIN);
 				}
 				else {
 					// Switch to announce state.
 					state = ANNOUNCE;
 					nclaims = 0;
-					VDBG("announce/%d %s@%s\n",
+					VDBG("announce/%u %s@%s\n",
 							nclaims, intf, inet_ntoa(ip));
 					arp(fd, &saddr, ARPOP_REQUEST,
 							&eth_addr, ip,
 							&eth_addr, ip);
-					timeout = ANNOUNCE_INTERVAL * 1000;
+					timeout_ms = ANNOUNCE_INTERVAL * 1000;
 				}
 				break;
 			case RATE_LIMIT_PROBE:
@@ -347,24 +341,24 @@ int zcip_main(int argc, char **argv)
 				// have been received, so we can move immediately to the announce state
 				state = ANNOUNCE;
 				nclaims = 0;
-				VDBG("announce/%d %s@%s\n",
+				VDBG("announce/%u %s@%s\n",
 						nclaims, intf, inet_ntoa(ip));
 				arp(fd, &saddr, ARPOP_REQUEST,
 						&eth_addr, ip,
 						&eth_addr, ip);
-				timeout = ANNOUNCE_INTERVAL * 1000;
+				timeout_ms = ANNOUNCE_INTERVAL * 1000;
 				break;
 			case ANNOUNCE:
 				// timeouts in the ANNOUNCE state mean no conflicting ARP packets
 				// have been received, so we can progress through the states
 				if (nclaims < ANNOUNCE_NUM) {
 					nclaims++;
-					VDBG("announce/%d %s@%s\n",
+					VDBG("announce/%u %s@%s\n",
 							nclaims, intf, inet_ntoa(ip));
 					arp(fd, &saddr, ARPOP_REQUEST,
 							&eth_addr, ip,
 							&eth_addr, ip);
-					timeout = ANNOUNCE_INTERVAL * 1000;
+					timeout_ms = ANNOUNCE_INTERVAL * 1000;
 				}
 				else {
 					// Switch to monitor state.
@@ -375,7 +369,7 @@ int zcip_main(int argc, char **argv)
 					run(script_av, intf, &ip);
 					ready = 1;
 					conflicts = 0;
-					timeout = -1; // Never timeout in the monitor state.
+					timeout_ms = -1; // Never timeout in the monitor state.
 
 					// NOTE: all other exit paths
 					// should deconfig ...
@@ -386,14 +380,14 @@ int zcip_main(int argc, char **argv)
 			case DEFEND:
 				// We won!  No ARP replies, so just go back to monitor.
 				state = MONITOR;
-				timeout = -1;
+				timeout_ms = -1;
 				conflicts = 0;
 				break;
 			default:
 				// Invalid, should never happen.  Restart the whole protocol.
 				state = PROBE;
 				pick(&ip);
-				timeout = 0;
+				timeout_ms = 0;
 				nprobes = 0;
 				nclaims = 0;
 				break;
@@ -403,20 +397,17 @@ int zcip_main(int argc, char **argv)
 		case 1:
 			// We need to adjust the timeout in case we didn't receive
 			// a conflicting packet.
-			if (timeout > 0) {
-				struct timeval tv2;
-
-				gettimeofday(&tv2, NULL);
-				if (timercmp(&tv1, &tv2, <)) {
+			if (timeout_ms > 0) {
+				unsigned diff = deadline_us - MONOTONIC_US();
+				if ((int)(diff) < 0) {
 					// Current time is greater than the expected timeout time.
 					// Should never happen.
 					VDBG("missed an expected timeout\n");
-					timeout = 0;
+					timeout_ms = 0;
 				} else {
 					VDBG("adjusting timeout\n");
-					timersub(&tv1, &tv2, &tv1);
-					timeout = 1000 * tv1.tv_sec
-							+ tv1.tv_usec / 1000;
+					timeout_ms = diff / 1000;
+					if (!timeout_ms) timeout_ms = 1;
 				}
 			}
 
@@ -484,13 +475,13 @@ int zcip_main(int argc, char **argv)
 					conflicts++;
 					if (conflicts >= MAX_CONFLICTS) {
 						VDBG("%s ratelimit\n", intf);
-						timeout = RATE_LIMIT_INTERVAL * 1000;
+						timeout_ms = RATE_LIMIT_INTERVAL * 1000;
 						state = RATE_LIMIT_PROBE;
 					}
 
 					// restart the whole protocol
 					pick(&ip);
-					timeout = 0;
+					timeout_ms = 0;
 					nprobes = 0;
 					nclaims = 0;
 				}
@@ -500,7 +491,7 @@ int zcip_main(int argc, char **argv)
 				if (source_ip_conflict) {
 					VDBG("monitor conflict -- defending\n");
 					state = DEFEND;
-					timeout = DEFEND_INTERVAL * 1000;
+					timeout_ms = DEFEND_INTERVAL * 1000;
 					arp(fd, &saddr,
 							ARPOP_REQUEST,
 							&eth_addr, ip,
@@ -518,7 +509,7 @@ int zcip_main(int argc, char **argv)
 
 					// restart the whole protocol
 					pick(&ip);
-					timeout = 0;
+					timeout_ms = 0;
 					nprobes = 0;
 					nclaims = 0;
 				}
@@ -528,7 +519,7 @@ int zcip_main(int argc, char **argv)
 				VDBG("invalid state -- starting over\n");
 				state = PROBE;
 				pick(&ip);
-				timeout = 0;
+				timeout_ms = 0;
 				nprobes = 0;
 				nclaims = 0;
 				break;