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
This commit is contained in:
Denis Vlasenko
@ -23,7 +23,6 @@
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// - avoid silent script failures, especially under load...
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// - link status monitoring (restart on link-up; stop on link-down)
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#include "libbb.h"
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#include <syslog.h>
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#include <poll.h>
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#include <sys/wait.h>
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@ -31,10 +30,13 @@
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#include <net/ethernet.h>
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#include <net/if.h>
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#include <net/if_arp.h>
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#include <linux/if_packet.h>
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#include <linux/sockios.h>
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#include "libbb.h"
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/* We don't need more than 32 bits of the counter */
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#define MONOTONIC_US() ((unsigned)monotonic_us())
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struct arp_packet {
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struct ether_header hdr;
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@ -78,15 +80,12 @@ static void pick(struct in_addr *ip)
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{
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unsigned tmp;
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/* use cheaper math than lrand48() mod N */
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do {
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tmp = (lrand48() >> 16) & IN_CLASSB_HOST;
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tmp = rand() & IN_CLASSB_HOST;
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} while (tmp > (IN_CLASSB_HOST - 0x0200));
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ip->s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
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}
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/* TODO: we need a flag to direct bb_[p]error_msg output to stderr. */
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/**
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* Broadcast an ARP packet.
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*/
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@ -151,7 +150,7 @@ static int run(char *argv[3], const char *intf, struct in_addr *ip)
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*/
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static unsigned ALWAYS_INLINE ms_rdelay(unsigned secs)
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{
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return lrand48() % (secs * 1000);
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return rand() % (secs * 1000);
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}
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/**
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@ -176,29 +175,31 @@ int zcip_main(int argc, char **argv)
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struct ifreq ifr;
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char *intf;
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char *script_av[3];
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suseconds_t timeout; // milliseconds
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int timeout_ms; /* must be signed */
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unsigned conflicts;
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unsigned nprobes;
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unsigned nclaims;
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int ready;
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int verbose;
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} L;
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#define null_ip (L.null_ip )
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#define null_addr (L.null_addr)
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#define saddr (L.saddr )
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#define ip (L.ip )
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#define ifr (L.ifr )
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#define intf (L.intf )
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#define script_av (L.script_av)
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#define timeout (L.timeout )
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#define conflicts (L.conflicts)
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#define nprobes (L.nprobes )
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#define nclaims (L.nclaims )
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#define ready (L.ready )
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#define verbose (L.verbose )
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#define null_ip (L.null_ip )
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#define null_addr (L.null_addr )
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#define saddr (L.saddr )
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#define ip (L.ip )
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#define ifr (L.ifr )
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#define intf (L.intf )
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#define script_av (L.script_av )
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#define timeout_ms (L.timeout_ms)
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#define conflicts (L.conflicts )
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#define nprobes (L.nprobes )
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#define nclaims (L.nclaims )
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#define ready (L.ready )
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#define verbose (L.verbose )
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memset(&L, 0, sizeof(L));
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srand(MONOTONIC_US());
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#define FOREGROUND (opts & 1)
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#define QUIT (opts & 2)
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// parse commandline: prog [options] ifname script
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@ -282,7 +283,7 @@ int zcip_main(int argc, char **argv)
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// - defend it, within limits
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while (1) {
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struct pollfd fds[1];
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struct timeval tv1;
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unsigned deadline_us;
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struct arp_packet p;
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int source_ip_conflict = 0;
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@ -293,24 +294,18 @@ int zcip_main(int argc, char **argv)
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fds[0].revents = 0;
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// poll, being ready to adjust current timeout
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if (!timeout) {
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timeout = ms_rdelay(PROBE_WAIT);
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if (!timeout_ms) {
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timeout_ms = ms_rdelay(PROBE_WAIT);
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// FIXME setsockopt(fd, SO_ATTACH_FILTER, ...) to
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// make the kernel filter out all packets except
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// ones we'd care about.
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}
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// set tv1 to the point in time when we timeout
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gettimeofday(&tv1, NULL);
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tv1.tv_usec += (timeout % 1000) * 1000;
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while (tv1.tv_usec > 1000000) {
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tv1.tv_usec -= 1000000;
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tv1.tv_sec++;
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}
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tv1.tv_sec += timeout / 1000;
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// set deadline_us to the point in time when we timeout
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deadline_us = MONOTONIC_US() + timeout_ms * 1000;
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VDBG("...wait %ld %s nprobes=%d, nclaims=%d\n",
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timeout, intf, nprobes, nclaims);
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switch (poll(fds, 1, timeout)) {
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VDBG("...wait %d %s nprobes=%u, nclaims=%u\n",
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timeout_ms, intf, nprobes, nclaims);
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switch (poll(fds, 1, timeout_ms)) {
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// timeout
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case 0:
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@ -321,25 +316,24 @@ int zcip_main(int argc, char **argv)
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// have been received, so we can progress through the states
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if (nprobes < PROBE_NUM) {
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nprobes++;
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VDBG("probe/%d %s@%s\n",
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VDBG("probe/%u %s@%s\n",
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nprobes, intf, inet_ntoa(ip));
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arp(fd, &saddr, ARPOP_REQUEST,
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ð_addr, null_ip,
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&null_addr, ip);
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timeout = PROBE_MIN * 1000;
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timeout += ms_rdelay(PROBE_MAX
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- PROBE_MIN);
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timeout_ms = PROBE_MIN * 1000;
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timeout_ms += ms_rdelay(PROBE_MAX - PROBE_MIN);
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}
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else {
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// Switch to announce state.
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state = ANNOUNCE;
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nclaims = 0;
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VDBG("announce/%d %s@%s\n",
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VDBG("announce/%u %s@%s\n",
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nclaims, intf, inet_ntoa(ip));
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arp(fd, &saddr, ARPOP_REQUEST,
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ð_addr, ip,
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ð_addr, ip);
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timeout = ANNOUNCE_INTERVAL * 1000;
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timeout_ms = ANNOUNCE_INTERVAL * 1000;
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}
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break;
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case RATE_LIMIT_PROBE:
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@ -347,24 +341,24 @@ int zcip_main(int argc, char **argv)
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// have been received, so we can move immediately to the announce state
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state = ANNOUNCE;
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nclaims = 0;
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VDBG("announce/%d %s@%s\n",
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VDBG("announce/%u %s@%s\n",
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nclaims, intf, inet_ntoa(ip));
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arp(fd, &saddr, ARPOP_REQUEST,
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ð_addr, ip,
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ð_addr, ip);
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timeout = ANNOUNCE_INTERVAL * 1000;
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timeout_ms = ANNOUNCE_INTERVAL * 1000;
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break;
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case ANNOUNCE:
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// timeouts in the ANNOUNCE state mean no conflicting ARP packets
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// have been received, so we can progress through the states
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if (nclaims < ANNOUNCE_NUM) {
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nclaims++;
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VDBG("announce/%d %s@%s\n",
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VDBG("announce/%u %s@%s\n",
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nclaims, intf, inet_ntoa(ip));
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arp(fd, &saddr, ARPOP_REQUEST,
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ð_addr, ip,
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ð_addr, ip);
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timeout = ANNOUNCE_INTERVAL * 1000;
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timeout_ms = ANNOUNCE_INTERVAL * 1000;
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}
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else {
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// Switch to monitor state.
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@ -375,7 +369,7 @@ int zcip_main(int argc, char **argv)
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run(script_av, intf, &ip);
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ready = 1;
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conflicts = 0;
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timeout = -1; // Never timeout in the monitor state.
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timeout_ms = -1; // Never timeout in the monitor state.
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// NOTE: all other exit paths
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// should deconfig ...
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@ -386,14 +380,14 @@ int zcip_main(int argc, char **argv)
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case DEFEND:
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// We won! No ARP replies, so just go back to monitor.
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state = MONITOR;
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timeout = -1;
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timeout_ms = -1;
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conflicts = 0;
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break;
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default:
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// Invalid, should never happen. Restart the whole protocol.
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state = PROBE;
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pick(&ip);
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timeout = 0;
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timeout_ms = 0;
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nprobes = 0;
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nclaims = 0;
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break;
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@ -403,20 +397,17 @@ int zcip_main(int argc, char **argv)
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case 1:
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// We need to adjust the timeout in case we didn't receive
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// a conflicting packet.
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if (timeout > 0) {
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struct timeval tv2;
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gettimeofday(&tv2, NULL);
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if (timercmp(&tv1, &tv2, <)) {
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if (timeout_ms > 0) {
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unsigned diff = deadline_us - MONOTONIC_US();
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if ((int)(diff) < 0) {
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// Current time is greater than the expected timeout time.
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// Should never happen.
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VDBG("missed an expected timeout\n");
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timeout = 0;
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timeout_ms = 0;
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} else {
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VDBG("adjusting timeout\n");
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timersub(&tv1, &tv2, &tv1);
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timeout = 1000 * tv1.tv_sec
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+ tv1.tv_usec / 1000;
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timeout_ms = diff / 1000;
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if (!timeout_ms) timeout_ms = 1;
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}
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}
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@ -484,13 +475,13 @@ int zcip_main(int argc, char **argv)
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conflicts++;
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if (conflicts >= MAX_CONFLICTS) {
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VDBG("%s ratelimit\n", intf);
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timeout = RATE_LIMIT_INTERVAL * 1000;
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timeout_ms = RATE_LIMIT_INTERVAL * 1000;
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state = RATE_LIMIT_PROBE;
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}
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// restart the whole protocol
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pick(&ip);
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timeout = 0;
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timeout_ms = 0;
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nprobes = 0;
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nclaims = 0;
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}
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@ -500,7 +491,7 @@ int zcip_main(int argc, char **argv)
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if (source_ip_conflict) {
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VDBG("monitor conflict -- defending\n");
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state = DEFEND;
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timeout = DEFEND_INTERVAL * 1000;
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timeout_ms = DEFEND_INTERVAL * 1000;
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arp(fd, &saddr,
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ARPOP_REQUEST,
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ð_addr, ip,
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@ -518,7 +509,7 @@ int zcip_main(int argc, char **argv)
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// restart the whole protocol
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pick(&ip);
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timeout = 0;
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timeout_ms = 0;
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nprobes = 0;
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nclaims = 0;
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}
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@ -528,7 +519,7 @@ int zcip_main(int argc, char **argv)
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VDBG("invalid state -- starting over\n");
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state = PROBE;
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pick(&ip);
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timeout = 0;
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timeout_ms = 0;
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nprobes = 0;
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nclaims = 0;
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break;
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