/*
 * 接口統(tǒng)計信息
 */
typedef struct nic_stats {
	struct timeval tv;		/* tv_sec, tv_usec */
	uint64_t rbytes;		/* total read bytes */
	uint64_t wbytes;		/* total written bytes */
	uint64_t rpackets;		/* total read packets */
	uint64_t wpackets;		/* total written packets */
	uint64_t ierr;			/* total input errors */
	uint64_t oerr;			/* total output errors */
	uint64_t coll;			/* total collisions */
	uint64_t nocp;			/* total nocanput */
	uint64_t defer;			/* total defers */
	uint64_t sat;			/* saturation value */
} nicstats_t;
/*
 * print_header - 打印標題行
 */
static void
print_header(void)
{
	if (g_style)
		(void) printf("%8s %5s %14s %14s\n",
		    "Time", "Int", "rKb/s", "wKb/s");
	else
		(void) printf(
		    "%8s %5s %7s %7s %7s %7s %7s %7s %7s %7s\n",
		    "Time", "Int", "rKb/s", "wKb/s", "rPk/s",
		    "wPk/s", "rAvs", "wAvs", "%Util", "Sat");
}
static int split_ifname(char *if_name, char *drv, uint32_t *instance)
{
...
	n = 0;
	for (p = if_name; *p; p++)
		n++;
	if (n <= 1)
		return (B_FALSE);
	m = n;
	for (p--; isdigit(*p); p--)
		n--;
	if (m == n || n == 0)
		return (B_FALSE);
	(void) strncpy(drv, if_name, n);
	drv[n] = '\0';
	*instance = (uint32_t)atol(++p);
...
}
...
static void update_ksp_by_type(kstat_t **kspp, uint32_t types, char *name)
{
...
	if (types & KS_LINK) 
	{
		*kspp = fetch_ksp("link", 0, name);
		return;
	}
	(void) split_ifname(name, drv, &instance);
	if (types & KS_DRV_MAC) 
	{
		*kspp = fetch_ksp(drv, instance, "mac");
		return;
	}
	if (types & KS_DIN) 
	{
		*kspp = fetch_ksp(drv, instance, name);
		return;
	}
	if (types & KS_DRV) {
		*kspp = fetch_ksp(drv, instance, NULL);
		return;
	}
	if (types & KS_NAME) {
		*kspp = fetch_ksp(name, -1, NULL);
		return;
	}
	...
}
static void update_stats(void)
{
...
	(void) gettimeofday(&now_tv, NULL);
	if (g_tcp) 
	{
		/* 更新TCP統(tǒng)計信息 */
		if (g_new_kstat_chain) 
		{
			g_tcp_ksp = kstat_lookup(g_kc, "tcp", -1, "tcp");
			if (! g_tcp_ksp)
				die(1, "kstat_lookup");
		}
		if (kstat_read(g_kc, g_tcp_ksp, NULL) < 0)
			die(1, "kstat_read");
		g_tcp_new->tv.tv_sec = now_tv.tv_sec;
		g_tcp_new->tv.tv_usec = now_tv.tv_usec;
		TCP_UPDATE(inDataInorderSegs, "inDataInorderSegs");
		TCP_UPDATE(outDataSegs, "outDataSegs");
		TCP_UPDATE(inDataInorderBytes, "inDataInorderBytes");
		TCP_UPDATE(inDataUnorderSegs, "inDataUnorderSegs");
		TCP_UPDATE(inDataUnorderBytes, "inDataUnorderBytes");
		TCP_UPDATE(outDataBytes, "outDataBytes");
		TCP_UPDATE(estabResets, "estabResets");
		TCP_UPDATE(outRsts, "outRsts");
		TCP_UPDATE(attemptFails, "attemptFails");
		TCP_UPDATE(retransBytes, "retransBytes");
		TCP_UPDATE(passiveOpens, "passiveOpens");
		TCP_UPDATE(activeOpens, "activeOpens");
		TCP_UPDATE(halfOpenDrop, "halfOpenDrop");
		TCP_UPDATE(listenDrop, "listenDrop");
		TCP_UPDATE(listenDropQ0, "listenDropQ0");
	}
	if (g_udp) 
	{
		/* 更新UDP統(tǒng)計信息 */
		if (g_new_kstat_chain) 
		{
			g_udp_ksp = kstat_lookup(g_kc, "udp", -1, "udp");
			if (! g_udp_ksp)
				die(1, "kstat_lookup");
		}
		if (kstat_read(g_kc, g_udp_ksp, NULL) < 0)
			die(1, "kstat_read");
		g_udp_new->tv.tv_sec = now_tv.tv_sec;
		g_udp_new->tv.tv_usec = now_tv.tv_usec;
		UDP_UPDATE(inDatagrams, "inDatagrams");
		UDP_UPDATE(outDatagrams, "outDatagrams");
		UDP_UPDATE(inErrors, "inErrors");
		UDP_UPDATE(outErrors, "outErrors");
	}
	if (g_style == STYLE_NONE && ! g_list)
		return;
	/* 更新接口統(tǒng)計信息 */
	for (nicp = g_nicdatap; nicp; nicp = nicp->next) 
	{
		if (! (nicp->flags & NIC_UP))
			/* 鏈接未打開 */
			continue;
		if (g_nonlocal && (nicp->flags & NIC_LOOPBACK))
			continue;
		if (! (nicp->flags & NIC_OK_UPDATED))
			if (kstat_read(g_kc, nicp->op_ksp, NULL) < 0)
				die(1, "kstat_read");
		/* 保存網絡值 */
		nicp->new.tv.tv_sec = now_tv.tv_sec;
		nicp->new.tv.tv_usec = now_tv.tv_usec;
		nicp->new.rbytes =
			fetch6432(nicp->op_ksp, "rbytes64", "rbytes", 0);
		nicp->new.wbytes =
			fetch6432(nicp->op_ksp, "obytes64", "obytes", 0);
		nicp->new.rpackets =
			fetch6432(nicp->op_ksp, "ipackets64", "ipackets", 0);
		nicp->new.wpackets =
			fetch6432(nicp->op_ksp, "opackets64", "opackets", 0);
		switch (g_style) 
		{
		case STYLE_EXTENDED_PARSEABLE:
		case STYLE_EXTENDED:
			nicp->new.ierr = fetch32(nicp->op_ksp, "ierrors", 0);
			nicp->new.oerr = fetch32(nicp->op_ksp, "oerrors", 0);
			/*FALLTHROUGH*/
		case STYLE_FULL:
		case STYLE_SUMMARY:
			nicp->new.coll = fetch32(nicp->op_ksp, "collisions",
				0);
			nicp->new.nocp = fetch_nocanput(nicp->op_ksp, 0);
			nicp->new.defer = fetch32(nicp->op_ksp, "defer_xmts",
				0);
			nicp->new.sat = nicp->new.defer + nicp->new.nocp +
				nicp->new.coll;
			nicp->new.sat += fetch32(nicp->op_ksp, "noxmtbuf", 0);
			break;
		}
		nicp->speed = fetch64(nicp->op_ksp, "ifspeed", 0);
		nicp->duplex = fetch32(nicp->op_ksp, "link_duplex", 0);
	}
...
}
static void load_snmp(FILE *snmp)
{
...
	/* 從/proc/net/snmp加載TCP和/或UDP統(tǒng)計信息 */
...
	while (remaining) 
	{
		p = fgets(buf, sizeof (buf), snmp);
		if (! p)
			break;
		if (g_tcp && strncmp("Tcp: RtoAlgorithm RtoMin RtoMax MaxConn "
				"ActiveOpens PassiveOpens AttemptFails "
				"EstabResets CurrEstab InSegs OutSegs "
				"RetransSegs InErrs OutRsts", p, 141) == 0) 
				{
			int n;
			n = fscanf(snmp, "Tcp: %lld %lld %lld %lld "
			    "%lld %lld %lld %lld %lld %lld "
			    "%lld %lld %lld %lld\n",
			    &ll[0], &ll[1], &ll[2], &ll[3],
			    &ll[4], &ll[5], &ll[6], &ll[7],
			    &ll[8], &ll[9], &ll[10], &ll[11],
			    &ll[12], &ll[13]);
			if (n == 14) 
			{
				g_tcp_new->inDataInorderSegs = ll[9];
				g_tcp_new->outDataSegs = ll[10];
				g_tcp_new->estabResets = ll[7];
				g_tcp_new->outRsts = ll[13];
				g_tcp_new->attemptFails = ll[6];
				/* Note: bytes */
				g_tcp_new->retransBytes = ll[11];
				g_tcp_new->passiveOpens = ll[5];
				g_tcp_new->activeOpens = ll[4];
			}
			remaining--;
		} 
		else if (g_udp && strncmp("Udp: InDatagrams NoPorts "
				"InErrors OutDatagrams RcvbufErrors "
				"SndbufErrors\n", p, 72) == 0) 
				{
			int n;
			n = fscanf(snmp, "Udp: %lld %lld %lld %lld "
			    "%lld %lld\n",
			    &ll[0], &ll[1], &ll[2], &ll[3],
			    &ll[4], &ll[5]);
			if (n == 6) 
			{
				g_udp_new->inDatagrams = ll[0];
				g_udp_new->outDatagrams = ll[3];
				g_udp_new->inErrors = ll[2]; /* + ll[4]? */
				g_udp_new->outErrors = ll[5];
			}
			remaining--;
		}
	}
}
...
static void update_timestr(time_t *tptr)
{
...
	if (tptr)
		t = *tptr;
	else
		t = time(NULL);
	tm = localtime(&t);
	(void) strftime(g_timestr, sizeof (g_timestr), "%H:%M:%S", tm);
}
static void sleep_for(hrtime_t period, hrtime_t start_n)
{
...
	do 
	{
		pause_tv.tv_sec = pause_n / NANOSEC;
		pause_tv.tv_nsec = pause_n % NANOSEC;
		status = nanosleep(&pause_tv, (struct timespec *)NULL);
		if (status < 0)
			if (errno == EINTR)
			 {
				now_n = gethrtime();
				pause_n = start_n + period - now_n;
				if (pause_n < 100)
					return;
			}
			 else 
			{
				...
			}
	} while (status != 0);
}
...