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Diffstat (limited to 'networking/zcip.c')
-rw-r--r--networking/zcip.c115
1 files changed, 53 insertions, 62 deletions
diff --git a/networking/zcip.c b/networking/zcip.c
index eb0a7ba..de4ee0b 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;
generated by cgit v1.1 at 2024-12-29 18:51:43 +0000