misc/nstat.c - platform/external/iproute2 - Gitiles

 /*
  * nstat.c	handy utility to read counters /proc/net/netstat and snmp
  *
  *		This program is free software; you can redistribute it and/or
  *		modify it under the terms of the GNU General Public License
  *		as published by the Free Software Foundation; either version
  *		2 of the License, or (at your option) any later version.
  *
  * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  */

 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <string.h>
 #include <errno.h>
 #include <time.h>
 #include <sys/time.h>
 #include <fnmatch.h>
 #include <sys/file.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <sys/poll.h>
 #include <sys/wait.h>
 #include <sys/stat.h>
 #include <signal.h>
 #include <math.h>
 #include <getopt.h>

 #include <json_writer.h>
 #include <SNAPSHOT.h>
 #include "utils.h"

 int dump_zeros;
 int reset_history;
 int ignore_history;
 int no_output;
 int json_output;
 int pretty;
 int no_update;
 int scan_interval;
 int time_constant;
 double W;
 char **patterns;
 int npatterns;

 char info_source[128];
 int source_mismatch;

 static int generic_proc_open(const char *env, char *name)
 {
 	char store[128];
 	char *p = getenv(env);

 	if (!p) {
 		p = getenv("PROC_ROOT") ? : "/proc";
 		snprintf(store, sizeof(store)-1, "%s/%s", p, name);
 		p = store;
 	}
 	return open(p, O_RDONLY);
 }

 static int net_netstat_open(void)
 {
 	return generic_proc_open("PROC_NET_NETSTAT", "net/netstat");
 }

 static int net_snmp_open(void)
 {
 	return generic_proc_open("PROC_NET_SNMP", "net/snmp");
 }

 static int net_snmp6_open(void)
 {
 	return generic_proc_open("PROC_NET_SNMP6", "net/snmp6");
 }

 struct nstat_ent {
 	struct nstat_ent *next;
 	char		 *id;
 	unsigned long long val;
 	double		   rate;
 };

 struct nstat_ent *kern_db;
 struct nstat_ent *hist_db;

 static const char *useless_numbers[] = {
 	"IpForwarding", "IpDefaultTTL",
 	"TcpRtoAlgorithm", "TcpRtoMin", "TcpRtoMax",
 	"TcpMaxConn", "TcpCurrEstab"
 };

 static int useless_number(const char *id)
 {
 	int i;

 	for (i = 0; i < ARRAY_SIZE(useless_numbers); i++)
 		if (strcmp(id, useless_numbers[i]) == 0)
 			return 1;
 	return 0;
 }

 static int match(const char *id)
 {
 	int i;

 	if (npatterns == 0)
 		return 1;

 	for (i = 0; i < npatterns; i++) {
 		if (!fnmatch(patterns[i], id, 0))
 			return 1;
 	}
 	return 0;
 }

 static void load_good_table(FILE *fp)
 {
 	char buf[4096];
 	struct nstat_ent *db = NULL;
 	struct nstat_ent *n;

 	while (fgets(buf, sizeof(buf), fp) != NULL) {
 		int nr;
 		unsigned long long val;
 		double rate;
 		char idbuf[sizeof(buf)];

 		if (buf[0] == '#') {
 			buf[strlen(buf)-1] = 0;
 			if (info_source[0] && strcmp(info_source, buf+1))
 				source_mismatch = 1;
 			info_source[0] = 0;
 			strncat(info_source, buf+1, sizeof(info_source)-1);
 			continue;
 		}
 		/* idbuf is as big as buf, so this is safe */
 		nr = sscanf(buf, "%s%llu%lg", idbuf, &val, &rate);
 		if (nr < 2)
 			abort();
 		if (nr < 3)
 			rate = 0;
 		if (useless_number(idbuf))
 			continue;
 		if ((n = malloc(sizeof(*n))) == NULL)
 			abort();
 		n->id = strdup(idbuf);
 		n->val = val;
 		n->rate = rate;
 		n->next = db;
 		db = n;
 	}

 	while (db) {
 		n = db;
 		db = db->next;
 		n->next = kern_db;
 		kern_db = n;
 	}
 }

 static int count_spaces(const char *line)
 {
 	int count = 0;
 	char c;

 	while ((c = *line++) != 0)
 		count += c == ' ' || c == '\n';
 	return count;
 }

 static void load_ugly_table(FILE *fp)
 {
 	char buf[4096];
 	struct nstat_ent *db = NULL;
 	struct nstat_ent *n;

 	while (fgets(buf, sizeof(buf), fp) != NULL) {
 		char idbuf[sizeof(buf)];
 		int  off;
 		char *p;
 		int count1, count2, skip = 0;

 		p = strchr(buf, ':');
 		if (!p)
 			abort();
 		count1 = count_spaces(buf);
 		*p = 0;
 		idbuf[0] = 0;
 		strncat(idbuf, buf, sizeof(idbuf) - 1);
 		off = p - buf;
 		p += 2;

 		while (*p) {
 			char *next;

 			if ((next = strchr(p, ' ')) != NULL)
 				*next++ = 0;
 			else if ((next = strchr(p, '\n')) != NULL)
 				*next++ = 0;
 			if (off < sizeof(idbuf)) {
 				idbuf[off] = 0;
 				strncat(idbuf, p, sizeof(idbuf) - off - 1);
 			}
 			n = malloc(sizeof(*n));
 			if (!n)
 				abort();
 			n->id = strdup(idbuf);
 			n->rate = 0;
 			n->next = db;
 			db = n;
 			p = next;
 		}
 		n = db;
 		if (fgets(buf, sizeof(buf), fp) == NULL)
 			abort();
 		count2 = count_spaces(buf);
 		if (count2 > count1)
 			skip = count2 - count1;
 		do {
 			p = strrchr(buf, ' ');
 			if (!p)
 				abort();
 			*p = 0;
 			if (sscanf(p+1, "%llu", &n->val) != 1)
 				abort();
 			/* Trick to skip "dummy" trailing ICMP MIB in 2.4 */
 			if (skip)
 				skip--;
 			else
 				n = n->next;
 		} while (p > buf + off + 2);
 	}

 	while (db) {
 		n = db;
 		db = db->next;
 		if (useless_number(n->id)) {
 			free(n->id);
 			free(n);
 		} else {
 			n->next = kern_db;
 			kern_db = n;
 		}
 	}
 }

 static void load_snmp(void)
 {
 	FILE *fp = fdopen(net_snmp_open(), "r");

 	if (fp) {
 		load_ugly_table(fp);
 		fclose(fp);
 	}
 }

 static void load_snmp6(void)
 {
 	FILE *fp = fdopen(net_snmp6_open(), "r");

 	if (fp) {
 		load_good_table(fp);
 		fclose(fp);
 	}
 }

 static void load_netstat(void)
 {
 	FILE *fp = fdopen(net_netstat_open(), "r");

 	if (fp) {
 		load_ugly_table(fp);
 		fclose(fp);
 	}
 }


 static void dump_kern_db(FILE *fp, int to_hist)
 {
 	json_writer_t *jw = json_output ? jsonw_new(fp) : NULL;
 	struct nstat_ent *n, *h;

 	h = hist_db;
 	if (jw) {
 		jsonw_start_object(jw);
 		jsonw_pretty(jw, pretty);
 		jsonw_name(jw, info_source);
 		jsonw_start_object(jw);
 	} else
 		fprintf(fp, "#%s\n", info_source);

 	for (n = kern_db; n; n = n->next) {
 		unsigned long long val = n->val;

 		if (!dump_zeros && !val && !n->rate)
 			continue;
 		if (!match(n->id)) {
 			struct nstat_ent *h1;

 			if (!to_hist)
 				continue;
 			for (h1 = h; h1; h1 = h1->next) {
 				if (strcmp(h1->id, n->id) == 0) {
 					val = h1->val;
 					h = h1->next;
 					break;
 				}
 			}
 		}

 		if (jw)
 			jsonw_uint_field(jw, n->id, val);
 		else
 			fprintf(fp, "%-32s%-16llu%6.1f\n", n->id, val, n->rate);
 	}

 	if (jw) {
 		jsonw_end_object(jw);

 		jsonw_end_object(jw);
 		jsonw_destroy(&jw);
 	}
 }

 static void dump_incr_db(FILE *fp)
 {
 	json_writer_t *jw = json_output ? jsonw_new(fp) : NULL;
 	struct nstat_ent *n, *h;

 	h = hist_db;
 	if (jw) {
 		jsonw_start_object(jw);
 		jsonw_pretty(jw, pretty);
 		jsonw_name(jw, info_source);
 		jsonw_start_object(jw);
 	} else
 		fprintf(fp, "#%s\n", info_source);

 	for (n = kern_db; n; n = n->next) {
 		int ovfl = 0;
 		unsigned long long val = n->val;
 		struct nstat_ent *h1;

 		for (h1 = h; h1; h1 = h1->next) {
 			if (strcmp(h1->id, n->id) == 0) {
 				if (val < h1->val) {
 					ovfl = 1;
 					val = h1->val;
 				}
 				val -= h1->val;
 				h = h1->next;
 				break;
 			}
 		}
 		if (!dump_zeros && !val && !n->rate)
 			continue;
 		if (!match(n->id))
 			continue;

 		if (jw)
 			jsonw_uint_field(jw, n->id, val);
 		else
 			fprintf(fp, "%-32s%-16llu%6.1f%s\n", n->id, val,
 				n->rate, ovfl?" (overflow)":"");
 	}

 	if (jw) {
 		jsonw_end_object(jw);

 		jsonw_end_object(jw);
 		jsonw_destroy(&jw);
 	}
 }

 static int children;

 static void sigchild(int signo)
 {
 }

 static void update_db(int interval)
 {
 	struct nstat_ent *n, *h;

 	n = kern_db;
 	kern_db = NULL;

 	load_netstat();
 	load_snmp6();
 	load_snmp();

 	h = kern_db;
 	kern_db = n;

 	for (n = kern_db; n; n = n->next) {
 		struct nstat_ent *h1;

 		for (h1 = h; h1; h1 = h1->next) {
 			if (strcmp(h1->id, n->id) == 0) {
 				double sample;
 				unsigned long long incr = h1->val - n->val;

 				n->val = h1->val;
 				sample = (double)incr * 1000.0 / interval;
 				if (interval >= scan_interval) {
 					n->rate += W*(sample-n->rate);
 				} else if (interval >= 1000) {
 					if (interval >= time_constant) {
 						n->rate = sample;
 					} else {
 						double w = W*(double)interval/scan_interval;

 						n->rate += w*(sample-n->rate);
 					}
 				}

 				while (h != h1) {
 					struct nstat_ent *tmp = h;

 					h = h->next;
 					free(tmp->id);
 					free(tmp);
 				};
 				h = h1->next;
 				free(h1->id);
 				free(h1);
 				break;
 			}
 		}
 	}
 }

 #define T_DIFF(a, b) (((a).tv_sec-(b).tv_sec)*1000 + ((a).tv_usec-(b).tv_usec)/1000)


 static void server_loop(int fd)
 {
 	struct timeval snaptime = { 0 };
 	struct pollfd p;

 	p.fd = fd;
 	p.events = p.revents = POLLIN;

 	sprintf(info_source, "%d.%lu sampling_interval=%d time_const=%d",
 		getpid(), (unsigned long)random(), scan_interval/1000, time_constant/1000);

 	load_netstat();
 	load_snmp6();
 	load_snmp();

 	for (;;) {
 		int status;
 		time_t tdiff;
 		struct timeval now;

 		gettimeofday(&now, NULL);
 		tdiff = T_DIFF(now, snaptime);
 		if (tdiff >= scan_interval) {
 			update_db(tdiff);
 			snaptime = now;
 			tdiff = 0;
 		}
 		if (poll(&p, 1, scan_interval - tdiff) > 0
 		    && (p.revents&POLLIN)) {
 			int clnt = accept(fd, NULL, NULL);

 			if (clnt >= 0) {
 				pid_t pid;

 				if (children >= 5) {
 					close(clnt);
 				} else if ((pid = fork()) != 0) {
 					if (pid > 0)
 						children++;
 					close(clnt);
 				} else {
 					FILE *fp = fdopen(clnt, "w");

 					if (fp)
 						dump_kern_db(fp, 0);
 					exit(0);
 				}
 			}
 		}
 		while (children && waitpid(-1, &status, WNOHANG) > 0)
 			children--;
 	}
 }

 static int verify_forging(int fd)
 {
 	struct ucred cred;
 	socklen_t olen = sizeof(cred);

 	if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, (void *)&cred, &olen) ||
 	    olen < sizeof(cred))
 		return -1;
 	if (cred.uid == getuid() || cred.uid == 0)
 		return 0;
 	return -1;
 }

 static void usage(void) __attribute__((noreturn));

 static void usage(void)
 {
 	fprintf(stderr,
 "Usage: nstat [OPTION] [ PATTERN [ PATTERN ] ]\n"
 "   -h, --help		this message\n"
 "   -a, --ignore	ignore history\n"
 "   -d, --scan=SECS	sample every statistics every SECS\n"
 "   -j, --json          format output in JSON\n"
 "   -n, --nooutput	do history only\n"
 "   -p, --pretty        pretty print\n"
 "   -r, --reset		reset history\n"
 "   -s, --noupdate	don\'t update history\n"
 "   -t, --interval=SECS	report average over the last SECS\n"
 "   -V, --version	output version information\n"
 "   -z, --zeros		show entries with zero activity\n");
 	exit(-1);
 }

 static const struct option longopts[] = {
 	{ "help", 0, 0, 'h' },
 	{ "ignore",  0,  0, 'a' },
 	{ "scan", 1, 0, 'd'},
 	{ "nooutput", 0, 0, 'n' },
 	{ "json", 0, 0, 'j' },
 	{ "reset", 0, 0, 'r' },
 	{ "noupdate", 0, 0, 's' },
 	{ "pretty", 0, 0, 'p' },
 	{ "interval", 1, 0, 't' },
 	{ "version", 0, 0, 'V' },
 	{ "zeros", 0, 0, 'z' },
 	{ 0 }
 };

 int main(int argc, char *argv[])
 {
 	char *hist_name;
 	struct sockaddr_un sun;
 	FILE *hist_fp = NULL;
 	int ch;
 	int fd;

 	while ((ch = getopt_long(argc, argv, "h?vVzrnasd:t:jp",
 				 longopts, NULL)) != EOF) {
 		switch (ch) {
 		case 'z':
 			dump_zeros = 1;
 			break;
 		case 'r':
 			reset_history = 1;
 			break;
 		case 'a':
 			ignore_history = 1;
 			break;
 		case 's':
 			no_update = 1;
 			break;
 		case 'n':
 			no_output = 1;
 			break;
 		case 'd':
 			scan_interval = 1000*atoi(optarg);
 			break;
 		case 't':
 			if (sscanf(optarg, "%d", &time_constant) != 1 ||
 			    time_constant <= 0) {
 				fprintf(stderr, "nstat: invalid time constant divisor\n");
 				exit(-1);
 			}
 			break;
 		case 'j':
 			json_output = 1;
 			break;
 		case 'p':
 			pretty = 1;
 			break;
 		case 'v':
 		case 'V':
 			printf("nstat utility, iproute2-ss%s\n", SNAPSHOT);
 			exit(0);
 		case 'h':
 		case '?':
 		default:
 			usage();
 		}
 	}

 	argc -= optind;
 	argv += optind;

 	sun.sun_family = AF_UNIX;
 	sun.sun_path[0] = 0;
 	sprintf(sun.sun_path+1, "nstat%d", getuid());

 	if (scan_interval > 0) {
 		if (time_constant == 0)
 			time_constant = 60;
 		time_constant *= 1000;
 		W = 1 - 1/exp(log(10)*(double)scan_interval/time_constant);
 		if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
 			perror("nstat: socket");
 			exit(-1);
 		}
 		if (bind(fd, (struct sockaddr *)&sun, 2+1+strlen(sun.sun_path+1)) < 0) {
 			perror("nstat: bind");
 			exit(-1);
 		}
 		if (listen(fd, 5) < 0) {
 			perror("nstat: listen");
 			exit(-1);
 		}
 		if (daemon(0, 0)) {
 			perror("nstat: daemon");
 			exit(-1);
 		}
 		signal(SIGPIPE, SIG_IGN);
 		signal(SIGCHLD, sigchild);
 		server_loop(fd);
 		exit(0);
 	}

 	patterns = argv;
 	npatterns = argc;

 	if ((hist_name = getenv("NSTAT_HISTORY")) == NULL) {
 		hist_name = malloc(128);
 		sprintf(hist_name, "/tmp/.nstat.u%d", getuid());
 	}

 	if (reset_history)
 		unlink(hist_name);

 	if (!ignore_history || !no_update) {
 		struct stat stb;

 		fd = open(hist_name, O_RDWR|O_CREAT|O_NOFOLLOW, 0600);
 		if (fd < 0) {
 			perror("nstat: open history file");
 			exit(-1);
 		}
 		if ((hist_fp = fdopen(fd, "r+")) == NULL) {
 			perror("nstat: fdopen history file");
 			exit(-1);
 		}
 		if (flock(fileno(hist_fp), LOCK_EX)) {
 			perror("nstat: flock history file");
 			exit(-1);
 		}
 		if (fstat(fileno(hist_fp), &stb) != 0) {
 			perror("nstat: fstat history file");
 			exit(-1);
 		}
 		if (stb.st_nlink != 1 || stb.st_uid != getuid()) {
 			fprintf(stderr, "nstat: something is so wrong with history file, that I prefer not to proceed.\n");
 			exit(-1);
 		}
 		if (!ignore_history) {
 			FILE *tfp;
 			long uptime = -1;

 			if ((tfp = fopen("/proc/uptime", "r")) != NULL) {
 				if (fscanf(tfp, "%ld", &uptime) != 1)
 					uptime = -1;
 				fclose(tfp);
 			}
 			if (uptime >= 0 && time(NULL) >= stb.st_mtime+uptime) {
 				fprintf(stderr, "nstat: history is aged out, resetting\n");
 				if (ftruncate(fileno(hist_fp), 0) < 0)
 					perror("nstat: ftruncate");
 			}
 		}

 		load_good_table(hist_fp);

 		hist_db = kern_db;
 		kern_db = NULL;
 	}

 	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) >= 0 &&
 	    (connect(fd, (struct sockaddr *)&sun, 2+1+strlen(sun.sun_path+1)) == 0
 	     || (strcpy(sun.sun_path+1, "nstat0"),
 		 connect(fd, (struct sockaddr *)&sun, 2+1+strlen(sun.sun_path+1)) == 0))
 	    && verify_forging(fd) == 0) {
 		FILE *sfp = fdopen(fd, "r");

 		load_good_table(sfp);
 		if (hist_db && source_mismatch) {
 			fprintf(stderr, "nstat: history is stale, ignoring it.\n");
 			hist_db = NULL;
 		}
 		fclose(sfp);
 	} else {
 		if (fd >= 0)
 			close(fd);
 		if (hist_db && info_source[0] && strcmp(info_source, "kernel")) {
 			fprintf(stderr, "nstat: history is stale, ignoring it.\n");
 			hist_db = NULL;
 			info_source[0] = 0;
 		}
 		load_netstat();
 		load_snmp6();
 		load_snmp();
 		if (info_source[0] == 0)
 			strcpy(info_source, "kernel");
 	}

 	if (!no_output) {
 		if (ignore_history || hist_db == NULL)
 			dump_kern_db(stdout, 0);
 		else
 			dump_incr_db(stdout);
 	}
 	if (!no_update) {
 		if (ftruncate(fileno(hist_fp), 0) < 0)
 			perror("nstat: ftruncate");
 		rewind(hist_fp);

 		json_output = 0;
 		dump_kern_db(hist_fp, 1);
 		fclose(hist_fp);
 	}
 	exit(0);
 }
	/*
	* nstat.c handy utility to read counters /proc/net/netstat and snmp
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*
	* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
	*/

	#include <stdio.h>
	#include <stdlib.h>
	#include <unistd.h>
	#include <fcntl.h>
	#include <string.h>
	#include <errno.h>
	#include <time.h>
	#include <sys/time.h>
	#include <fnmatch.h>
	#include <sys/file.h>
	#include <sys/socket.h>
	#include <sys/un.h>
	#include <sys/poll.h>
	#include <sys/wait.h>
	#include <sys/stat.h>
	#include <signal.h>
	#include <math.h>
	#include <getopt.h>

	#include <json_writer.h>
	#include <SNAPSHOT.h>
	#include "utils.h"

	int dump_zeros;
	int reset_history;
	int ignore_history;
	int no_output;
	int json_output;
	int pretty;
	int no_update;
	int scan_interval;
	int time_constant;
	double W;
	char **patterns;
	int npatterns;

	char info_source[128];
	int source_mismatch;

	static int generic_proc_open(const char env, char name)
	{
	char store[128];
	char *p = getenv(env);

	if (!p) {
	p = getenv("PROC_ROOT") ? : "/proc";
	snprintf(store, sizeof(store)-1, "%s/%s", p, name);
	p = store;
	}
	return open(p, O_RDONLY);
	}

	static int net_netstat_open(void)
	{
	return generic_proc_open("PROC_NET_NETSTAT", "net/netstat");
	}

	static int net_snmp_open(void)
	{
	return generic_proc_open("PROC_NET_SNMP", "net/snmp");
	}

	static int net_snmp6_open(void)
	{
	return generic_proc_open("PROC_NET_SNMP6", "net/snmp6");
	}

	struct nstat_ent {
	struct nstat_ent *next;
	char *id;
	unsigned long long val;
	double rate;
	};

	struct nstat_ent *kern_db;
	struct nstat_ent *hist_db;

	static const char *useless_numbers[] = {
	"IpForwarding", "IpDefaultTTL",
	"TcpRtoAlgorithm", "TcpRtoMin", "TcpRtoMax",
	"TcpMaxConn", "TcpCurrEstab"
	};

	static int useless_number(const char *id)
	{
	int i;

	for (i = 0; i < ARRAY_SIZE(useless_numbers); i++)
	if (strcmp(id, useless_numbers[i]) == 0)
	return 1;
	return 0;
	}

	static int match(const char *id)
	{
	int i;

	if (npatterns == 0)
	return 1;

	for (i = 0; i < npatterns; i++) {
	if (!fnmatch(patterns[i], id, 0))
	return 1;
	}
	return 0;
	}

	static void load_good_table(FILE *fp)
	{
	char buf[4096];
	struct nstat_ent *db = NULL;
	struct nstat_ent *n;

	while (fgets(buf, sizeof(buf), fp) != NULL) {
	int nr;
	unsigned long long val;
	double rate;
	char idbuf[sizeof(buf)];

	if (buf[0] == '#') {
	buf[strlen(buf)-1] = 0;
	if (info_source[0] && strcmp(info_source, buf+1))
	source_mismatch = 1;
	info_source[0] = 0;
	strncat(info_source, buf+1, sizeof(info_source)-1);
	continue;
	}
	/* idbuf is as big as buf, so this is safe */
	nr = sscanf(buf, "%s%llu%lg", idbuf, &val, &rate);
	if (nr < 2)
	abort();
	if (nr < 3)
	rate = 0;
	if (useless_number(idbuf))
	continue;
	if ((n = malloc(sizeof(*n))) == NULL)
	abort();
	n->id = strdup(idbuf);
	n->val = val;
	n->rate = rate;
	n->next = db;
	db = n;
	}

	while (db) {
	n = db;
	db = db->next;
	n->next = kern_db;
	kern_db = n;
	}
	}

	static int count_spaces(const char *line)
	{
	int count = 0;
	char c;

	while ((c = *line++) != 0)
	count += c == ' ' \|\| c == '\n';
	return count;
	}

	static void load_ugly_table(FILE *fp)
	{
	char buf[4096];
	struct nstat_ent *db = NULL;
	struct nstat_ent *n;

	while (fgets(buf, sizeof(buf), fp) != NULL) {
	char idbuf[sizeof(buf)];
	int off;
	char *p;
	int count1, count2, skip = 0;

	p = strchr(buf, ':');
	if (!p)
	abort();
	count1 = count_spaces(buf);
	*p = 0;
	idbuf[0] = 0;
	strncat(idbuf, buf, sizeof(idbuf) - 1);
	off = p - buf;
	p += 2;

	while (*p) {
	char *next;

	if ((next = strchr(p, ' ')) != NULL)
	*next++ = 0;
	else if ((next = strchr(p, '\n')) != NULL)
	*next++ = 0;
	if (off < sizeof(idbuf)) {
	idbuf[off] = 0;
	strncat(idbuf, p, sizeof(idbuf) - off - 1);
	}
	n = malloc(sizeof(*n));
	if (!n)
	abort();
	n->id = strdup(idbuf);
	n->rate = 0;
	n->next = db;
	db = n;
	p = next;
	}
	n = db;
	if (fgets(buf, sizeof(buf), fp) == NULL)
	abort();
	count2 = count_spaces(buf);
	if (count2 > count1)
	skip = count2 - count1;
	do {
	p = strrchr(buf, ' ');
	if (!p)
	abort();
	*p = 0;
	if (sscanf(p+1, "%llu", &n->val) != 1)
	abort();
	/* Trick to skip "dummy" trailing ICMP MIB in 2.4 */
	if (skip)
	skip--;
	else
	n = n->next;
	} while (p > buf + off + 2);
	}

	while (db) {
	n = db;
	db = db->next;
	if (useless_number(n->id)) {
	free(n->id);
	free(n);
	} else {
	n->next = kern_db;
	kern_db = n;
	}
	}
	}

	static void load_snmp(void)
	{
	FILE *fp = fdopen(net_snmp_open(), "r");

	if (fp) {
	load_ugly_table(fp);
	fclose(fp);
	}
	}

	static void load_snmp6(void)
	{
	FILE *fp = fdopen(net_snmp6_open(), "r");

	if (fp) {
	load_good_table(fp);
	fclose(fp);
	}
	}

	static void load_netstat(void)
	{
	FILE *fp = fdopen(net_netstat_open(), "r");

	if (fp) {
	load_ugly_table(fp);
	fclose(fp);
	}
	}


	static void dump_kern_db(FILE *fp, int to_hist)
	{
	json_writer_t *jw = json_output ? jsonw_new(fp) : NULL;
	struct nstat_ent n, h;

	h = hist_db;
	if (jw) {
	jsonw_start_object(jw);
	jsonw_pretty(jw, pretty);
	jsonw_name(jw, info_source);
	jsonw_start_object(jw);
	} else
	fprintf(fp, "#%s\n", info_source);

	for (n = kern_db; n; n = n->next) {
	unsigned long long val = n->val;

	if (!dump_zeros && !val && !n->rate)
	continue;
	if (!match(n->id)) {
	struct nstat_ent *h1;

	if (!to_hist)
	continue;
	for (h1 = h; h1; h1 = h1->next) {
	if (strcmp(h1->id, n->id) == 0) {
	val = h1->val;
	h = h1->next;
	break;
	}
	}
	}

	if (jw)
	jsonw_uint_field(jw, n->id, val);
	else
	fprintf(fp, "%-32s%-16llu%6.1f\n", n->id, val, n->rate);
	}

	if (jw) {
	jsonw_end_object(jw);

	jsonw_end_object(jw);
	jsonw_destroy(&jw);
	}
	}

	static void dump_incr_db(FILE *fp)
	{
	json_writer_t *jw = json_output ? jsonw_new(fp) : NULL;
	struct nstat_ent n, h;

	h = hist_db;
	if (jw) {
	jsonw_start_object(jw);
	jsonw_pretty(jw, pretty);
	jsonw_name(jw, info_source);
	jsonw_start_object(jw);
	} else
	fprintf(fp, "#%s\n", info_source);

	for (n = kern_db; n; n = n->next) {
	int ovfl = 0;
	unsigned long long val = n->val;
	struct nstat_ent *h1;

	for (h1 = h; h1; h1 = h1->next) {
	if (strcmp(h1->id, n->id) == 0) {
	if (val < h1->val) {
	ovfl = 1;
	val = h1->val;
	}
	val -= h1->val;
	h = h1->next;
	break;
	}
	}
	if (!dump_zeros && !val && !n->rate)
	continue;
	if (!match(n->id))
	continue;

	if (jw)
	jsonw_uint_field(jw, n->id, val);
	else
	fprintf(fp, "%-32s%-16llu%6.1f%s\n", n->id, val,
	n->rate, ovfl?" (overflow)":"");
	}

	if (jw) {
	jsonw_end_object(jw);

	jsonw_end_object(jw);
	jsonw_destroy(&jw);
	}
	}

	static int children;

	static void sigchild(int signo)
	{
	}

	static void update_db(int interval)
	{
	struct nstat_ent n, h;

	n = kern_db;
	kern_db = NULL;

	load_netstat();
	load_snmp6();
	load_snmp();

	h = kern_db;
	kern_db = n;

	for (n = kern_db; n; n = n->next) {
	struct nstat_ent *h1;

	for (h1 = h; h1; h1 = h1->next) {
	if (strcmp(h1->id, n->id) == 0) {
	double sample;
	unsigned long long incr = h1->val - n->val;

	n->val = h1->val;
	sample = (double)incr * 1000.0 / interval;
	if (interval >= scan_interval) {
	n->rate += W*(sample-n->rate);
	} else if (interval >= 1000) {
	if (interval >= time_constant) {
	n->rate = sample;
	} else {
	double w = W*(double)interval/scan_interval;

	n->rate += w*(sample-n->rate);
	}
	}

	while (h != h1) {
	struct nstat_ent *tmp = h;

	h = h->next;
	free(tmp->id);
	free(tmp);
	};
	h = h1->next;
	free(h1->id);
	free(h1);
	break;
	}
	}
	}
	}

	#define T_DIFF(a, b) (((a).tv_sec-(b).tv_sec)*1000 + ((a).tv_usec-(b).tv_usec)/1000)


	static void server_loop(int fd)
	{
	struct timeval snaptime = { 0 };
	struct pollfd p;

	p.fd = fd;
	p.events = p.revents = POLLIN;

	sprintf(info_source, "%d.%lu sampling_interval=%d time_const=%d",
	getpid(), (unsigned long)random(), scan_interval/1000, time_constant/1000);

	load_netstat();
	load_snmp6();
	load_snmp();

	for (;;) {
	int status;
	time_t tdiff;
	struct timeval now;

	gettimeofday(&now, NULL);
	tdiff = T_DIFF(now, snaptime);
	if (tdiff >= scan_interval) {
	update_db(tdiff);
	snaptime = now;
	tdiff = 0;
	}
	if (poll(&p, 1, scan_interval - tdiff) > 0
	&& (p.revents&POLLIN)) {
	int clnt = accept(fd, NULL, NULL);

	if (clnt >= 0) {
	pid_t pid;

	if (children >= 5) {
	close(clnt);
	} else if ((pid = fork()) != 0) {
	if (pid > 0)
	children++;
	close(clnt);
	} else {
	FILE *fp = fdopen(clnt, "w");

	if (fp)
	dump_kern_db(fp, 0);
	exit(0);
	}
	}
	}
	while (children && waitpid(-1, &status, WNOHANG) > 0)
	children--;
	}
	}

	static int verify_forging(int fd)
	{
	struct ucred cred;
	socklen_t olen = sizeof(cred);

	if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, (void *)&cred, &olen) \|\|
	olen < sizeof(cred))
	return -1;
	if (cred.uid == getuid() \|\| cred.uid == 0)
	return 0;
	return -1;
	}

	static void usage(void) __attribute__((noreturn));

	static void usage(void)
	{
	fprintf(stderr,
	"Usage: nstat [OPTION] [ PATTERN [ PATTERN ] ]\n"
	" -h, --help this message\n"
	" -a, --ignore ignore history\n"
	" -d, --scan=SECS sample every statistics every SECS\n"
	" -j, --json format output in JSON\n"
	" -n, --nooutput do history only\n"
	" -p, --pretty pretty print\n"
	" -r, --reset reset history\n"
	" -s, --noupdate don\'t update history\n"
	" -t, --interval=SECS report average over the last SECS\n"
	" -V, --version output version information\n"
	" -z, --zeros show entries with zero activity\n");
	exit(-1);
	}

	static const struct option longopts[] = {
	{ "help", 0, 0, 'h' },
	{ "ignore", 0, 0, 'a' },
	{ "scan", 1, 0, 'd'},
	{ "nooutput", 0, 0, 'n' },
	{ "json", 0, 0, 'j' },
	{ "reset", 0, 0, 'r' },
	{ "noupdate", 0, 0, 's' },
	{ "pretty", 0, 0, 'p' },
	{ "interval", 1, 0, 't' },
	{ "version", 0, 0, 'V' },
	{ "zeros", 0, 0, 'z' },
	{ 0 }
	};

	int main(int argc, char *argv[])
	{
	char *hist_name;
	struct sockaddr_un sun;
	FILE *hist_fp = NULL;
	int ch;
	int fd;

	while ((ch = getopt_long(argc, argv, "h?vVzrnasd:t:jp",
	longopts, NULL)) != EOF) {
	switch (ch) {
	case 'z':
	dump_zeros = 1;
	break;
	case 'r':
	reset_history = 1;
	break;
	case 'a':
	ignore_history = 1;
	break;
	case 's':
	no_update = 1;
	break;
	case 'n':
	no_output = 1;
	break;
	case 'd':
	scan_interval = 1000*atoi(optarg);
	break;
	case 't':
	if (sscanf(optarg, "%d", &time_constant) != 1 \|\|
	time_constant <= 0) {
	fprintf(stderr, "nstat: invalid time constant divisor\n");
	exit(-1);
	}
	break;
	case 'j':
	json_output = 1;
	break;
	case 'p':
	pretty = 1;
	break;
	case 'v':
	case 'V':
	printf("nstat utility, iproute2-ss%s\n", SNAPSHOT);
	exit(0);
	case 'h':
	case '?':
	default:
	usage();
	}
	}

	argc -= optind;
	argv += optind;

	sun.sun_family = AF_UNIX;
	sun.sun_path[0] = 0;
	sprintf(sun.sun_path+1, "nstat%d", getuid());

	if (scan_interval > 0) {
	if (time_constant == 0)
	time_constant = 60;
	time_constant *= 1000;
	W = 1 - 1/exp(log(10)*(double)scan_interval/time_constant);
	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
	perror("nstat: socket");
	exit(-1);
	}
	if (bind(fd, (struct sockaddr *)&sun, 2+1+strlen(sun.sun_path+1)) < 0) {
	perror("nstat: bind");
	exit(-1);
	}
	if (listen(fd, 5) < 0) {
	perror("nstat: listen");
	exit(-1);
	}
	if (daemon(0, 0)) {
	perror("nstat: daemon");
	exit(-1);
	}
	signal(SIGPIPE, SIG_IGN);
	signal(SIGCHLD, sigchild);
	server_loop(fd);
	exit(0);
	}

	patterns = argv;
	npatterns = argc;

	if ((hist_name = getenv("NSTAT_HISTORY")) == NULL) {
	hist_name = malloc(128);
	sprintf(hist_name, "/tmp/.nstat.u%d", getuid());
	}

	if (reset_history)
	unlink(hist_name);

	if (!ignore_history \|\| !no_update) {
	struct stat stb;

	fd = open(hist_name, O_RDWR\|O_CREAT\|O_NOFOLLOW, 0600);
	if (fd < 0) {
	perror("nstat: open history file");
	exit(-1);
	}
	if ((hist_fp = fdopen(fd, "r+")) == NULL) {
	perror("nstat: fdopen history file");
	exit(-1);
	}
	if (flock(fileno(hist_fp), LOCK_EX)) {
	perror("nstat: flock history file");
	exit(-1);
	}
	if (fstat(fileno(hist_fp), &stb) != 0) {
	perror("nstat: fstat history file");
	exit(-1);
	}
	if (stb.st_nlink != 1 \|\| stb.st_uid != getuid()) {
	fprintf(stderr, "nstat: something is so wrong with history file, that I prefer not to proceed.\n");
	exit(-1);
	}
	if (!ignore_history) {
	FILE *tfp;
	long uptime = -1;

	if ((tfp = fopen("/proc/uptime", "r")) != NULL) {
	if (fscanf(tfp, "%ld", &uptime) != 1)
	uptime = -1;
	fclose(tfp);
	}
	if (uptime >= 0 && time(NULL) >= stb.st_mtime+uptime) {
	fprintf(stderr, "nstat: history is aged out, resetting\n");
	if (ftruncate(fileno(hist_fp), 0) < 0)
	perror("nstat: ftruncate");
	}
	}

	load_good_table(hist_fp);

	hist_db = kern_db;
	kern_db = NULL;
	}

	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) >= 0 &&
	(connect(fd, (struct sockaddr *)&sun, 2+1+strlen(sun.sun_path+1)) == 0
	\|\| (strcpy(sun.sun_path+1, "nstat0"),
	connect(fd, (struct sockaddr *)&sun, 2+1+strlen(sun.sun_path+1)) == 0))
	&& verify_forging(fd) == 0) {
	FILE *sfp = fdopen(fd, "r");

	load_good_table(sfp);
	if (hist_db && source_mismatch) {
	fprintf(stderr, "nstat: history is stale, ignoring it.\n");
	hist_db = NULL;
	}
	fclose(sfp);
	} else {
	if (fd >= 0)
	close(fd);
	if (hist_db && info_source[0] && strcmp(info_source, "kernel")) {
	fprintf(stderr, "nstat: history is stale, ignoring it.\n");
	hist_db = NULL;
	info_source[0] = 0;
	}
	load_netstat();
	load_snmp6();
	load_snmp();
	if (info_source[0] == 0)
	strcpy(info_source, "kernel");
	}

	if (!no_output) {
	if (ignore_history \|\| hist_db == NULL)
	dump_kern_db(stdout, 0);
	else
	dump_incr_db(stdout);
	}
	if (!no_update) {
	if (ftruncate(fileno(hist_fp), 0) < 0)
	perror("nstat: ftruncate");
	rewind(hist_fp);

	json_output = 0;
	dump_kern_db(hist_fp, 1);
	fclose(hist_fp);
	}
	exit(0);
	}