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;