/*

 * rtacct.c		Applet to display contents of /proc/net/rt_acct.

 *

 *		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 <sys/mman.h>

#include <signal.h>

#include <math.h>

#include "rt_names.h"

#include <SNAPSHOT.h>

int reset_history;

int ignore_history;

int no_output;

int no_update;

int scan_interval;

int time_constant;

int dump_zeros;

unsigned long magic_number;

double W;

static int generic_proc_open(const char *env, const char *name)

{

	char store[1024];

	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_rtacct_open(void)

{

	return generic_proc_open("PROC_NET_RTACCT", "net/rt_acct");

}

static __u32 rmap[256/4];

struct rtacct_data {

	__u32			ival[256*4];

	unsigned long long	val[256*4];

	double			rate[256*4];

	char			signature[128];

};

static struct rtacct_data kern_db_static;

static struct rtacct_data *kern_db = &kern_db_static;

static struct rtacct_data *hist_db;

static void nread(int fd, char *buf, int tot)

{

	int count = 0;

	while (count < tot) {

		int n = read(fd, buf+count, tot-count);

		if (n < 0) {

			if (errno == EINTR)

				continue;

			exit(-1);

		}

		if (n == 0)

			exit(-1);

		count += n;

	}

}

static __u32 *read_kern_table(__u32 *tbl)

{

	static __u32 *tbl_ptr;

	int fd;

	if (magic_number) {

		if (tbl_ptr != NULL)

			return tbl_ptr;

		fd = open("/dev/mem", O_RDONLY);

		if (fd < 0) {

			perror("magic open");

			exit(-1);

		}

		tbl_ptr = mmap(NULL, 4096,

			       PROT_READ,

			       MAP_SHARED,

			       fd, magic_number);

		if ((unsigned long)tbl_ptr == ~0UL) {

			perror("magic mmap");

			exit(-1);

		}

		close(fd);

		return tbl_ptr;

	}

	fd = net_rtacct_open();

	if (fd >= 0) {

		nread(fd, (char *)tbl, 256*16);

		close(fd);

	} else {

		memset(tbl, 0, 256*16);

	}

	return tbl;

}

static void format_rate(FILE *fp, double rate)

{

	char temp[64];

	if (rate > 1024*1024) {

		sprintf(temp, "%uM", (unsigned int)rint(rate/(1024*1024)));

		fprintf(fp, " %-10s", temp);

	} else if (rate > 1024) {

		sprintf(temp, "%uK", (unsigned int)rint(rate/1024));

		fprintf(fp, " %-10s", temp);

	} else

		fprintf(fp, " %-10u", (unsigned int)rate);

}

static void format_count(FILE *fp, unsigned long long val)

{

	if (val > 1024*1024*1024)

		fprintf(fp, " %10lluM", val/(1024*1024));

	else if (val > 1024*1024)

		fprintf(fp, " %10lluK", val/1024);

	else

		fprintf(fp, " %10llu", val);

}

static void dump_abs_db(FILE *fp)

{

	int realm;

	char b1[16];

	if (!no_output) {

		fprintf(fp, "#%s\n", kern_db->signature);

		fprintf(fp,

"%-10s %-10s "

"%-10s %-10s "

"%-10s \n"

		       , "Realm", "BytesTo", "PktsTo", "BytesFrom", "PktsFrom");

		fprintf(fp,

"%-10s %-10s "

"%-10s %-10s "

"%-10s \n"

		       , "", "BPSTo", "PPSTo", "BPSFrom", "PPSFrom");

	}

	for (realm = 0; realm < 256; realm++) {

		int i;

		unsigned long long *val;

		double		   *rate;

		if (!(rmap[realm>>5] & (1<<(realm&0x1f))))

			continue;

		val = &kern_db->val[realm*4];

		rate = &kern_db->rate[realm*4];

		if (!dump_zeros &&

		    !val[0] && !rate[0] &&

		    !val[1] && !rate[1] &&

		    !val[2] && !rate[2] &&

		    !val[3] && !rate[3])

			continue;

		if (hist_db) {

			memcpy(&hist_db->val[realm*4], val, sizeof(*val)*4);

		}

		if (no_output)

			continue;

		fprintf(fp, "%-10s", rtnl_rtrealm_n2a(realm, b1, sizeof(b1)));

		for (i = 0; i < 4; i++)

			format_count(fp, val[i]);

		fprintf(fp, "\n%-10s", "");

		for (i = 0; i < 4; i++)

			format_rate(fp, rate[i]);

		fprintf(fp, "\n");

	}

}

static void dump_incr_db(FILE *fp)

{

	int k, realm;

	char b1[16];

	if (!no_output) {

		fprintf(fp, "#%s\n", kern_db->signature);

		fprintf(fp,

"%-10s %-10s "

"%-10s %-10s "

"%-10s \n"

		       , "Realm", "BytesTo", "PktsTo", "BytesFrom", "PktsFrom");

		fprintf(fp,

"%-10s %-10s "

"%-10s %-10s "

"%-10s \n"

		       , "", "BPSTo", "PPSTo", "BPSFrom", "PPSFrom");

	}

	for (realm = 0; realm < 256; realm++) {

		int ovfl = 0;

		int i;

		unsigned long long *val;

		double		   *rate;

		unsigned long long rval[4];

		if (!(rmap[realm>>5] & (1<<(realm&0x1f))))

			continue;

		val = &kern_db->val[realm*4];

		rate = &kern_db->rate[realm*4];

		for (k = 0; k < 4; k++) {

			rval[k] = val[k];

			if (rval[k] < hist_db->val[realm*4+k])

				ovfl = 1;

			else

				rval[k] -= hist_db->val[realm*4+k];

		}

		if (ovfl) {

			for (k = 0; k < 4; k++)

				rval[k] = val[k];

		}

		if (hist_db) {

			memcpy(&hist_db->val[realm*4], val, sizeof(*val)*4);

		}

		if (no_output)

			continue;

		if (!dump_zeros &&

		    !rval[0] && !rate[0] &&

		    !rval[1] && !rate[1] &&

		    !rval[2] && !rate[2] &&

		    !rval[3] && !rate[3])

			continue;

		fprintf(fp, "%-10s", rtnl_rtrealm_n2a(realm, b1, sizeof(b1)));

		for (i = 0; i < 4; i++)

			format_count(fp, rval[i]);

		fprintf(fp, "\n%-10s", "");

		for (i = 0; i < 4; i++)

			format_rate(fp, rate[i]);

		fprintf(fp, "\n");

	}

}

static int children;

static void sigchild(int signo)

{

}

/* Server side only: read kernel data, update tables, calculate rates. */

static void update_db(int interval)

{

	int i;

	__u32 *ival;

	__u32 _ival[256*4];

	ival = read_kern_table(_ival);

	for (i = 0; i < 256*4; i++) {

		double sample;

		__u32 incr = ival[i] - kern_db->ival[i];

		if (ival[i] == 0 && incr == 0 &&

		    kern_db->val[i] == 0 && kern_db->rate[i] == 0)

			continue;

		kern_db->val[i] += incr;

		kern_db->ival[i] = ival[i];

		sample = (double)(incr*1000)/interval;

		if (interval >= scan_interval) {

			kern_db->rate[i] += W*(sample-kern_db->rate[i]);

		} else if (interval >= 1000) {

			if (interval >= time_constant) {

				kern_db->rate[i] = sample;

			} else {

				double w = W*(double)interval/scan_interval;

				kern_db->rate[i] += w*(sample-kern_db->rate[i]);

			}

		}

	}

}

static void send_db(int fd)

{

	int tot = 0;

	while (tot < sizeof(*kern_db)) {

		int n = write(fd, ((char *)kern_db) + tot, sizeof(*kern_db)-tot);

		if (n < 0) {

			if (errno == EINTR)

				continue;

			return;

		}

		tot += n;

	}

}

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

static void pad_kern_table(struct rtacct_data *dat, __u32 *ival)

{

	int i;

	memset(dat->rate, 0, sizeof(dat->rate));

	if (dat->ival != ival)

		memcpy(dat->ival, ival, sizeof(dat->ival));

	for (i = 0; i < 256*4; i++)

		dat->val[i] = ival[i];

}

static void server_loop(int fd)

{

	struct timeval snaptime = { 0 };

	struct pollfd p;

	p.fd = fd;

	p.events = p.revents = POLLIN;

	sprintf(kern_db->signature,

		"%u.%lu sampling_interval=%d time_const=%d",

		(unsigned int) getpid(), (unsigned long)random(),

		scan_interval/1000, time_constant/1000);

	pad_kern_table(kern_db, read_kern_table(kern_db->ival));

	for (;;) {

		int status;

		int 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, tdiff + scan_interval) > 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 {

					if (tdiff > 0)

						update_db(tdiff);

					send_db(clnt);

					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: rtacct [ -h?vVzrnasd:t: ] [ ListOfRealms ]\n"

		);

	exit(-1);

}

int main(int argc, char *argv[])

{

	char hist_name[128];

	struct sockaddr_un sun;

	int ch;

	int fd;

	while ((ch = getopt(argc, argv, "h?vVzrM:nasd:t:")) != 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, "rtacct: invalid time constant divisor\n");

				exit(-1);

			}

			break;

		case 'v':

		case 'V':

			printf("rtacct utility, iproute2-ss%s\n", SNAPSHOT);

			exit(0);

		case 'M':

			/* Some secret undocumented option, nobody

			 * is expected to ask about its sense. See?

			 */

			sscanf(optarg, "%lx", &magic_number);

			break;

		case 'h':

		case '?':

		default:

			usage();

		}

	}

	argc -= optind;

	argv += optind;

	if (argc) {

		while (argc > 0) {

			__u32 realm;

			if (rtnl_rtrealm_a2n(&realm, argv[0])) {

				fprintf(stderr, "Warning: realm \"%s\" does not exist.\n", argv[0]);

				exit(-1);

			}

			rmap[realm>>5] |= (1<<(realm&0x1f));

			argc--; argv++;

		}

	} else {

		memset(rmap, ~0, sizeof(rmap));

		/* Always suppress zeros. */

		dump_zeros = 0;

	}

	sun.sun_family = AF_UNIX;

	sun.sun_path[0] = 0;

	sprintf(sun.sun_path+1, "rtacct%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("rtacct: socket");

			exit(-1);

		}

		if (bind(fd, (struct sockaddr *)&sun, 2+1+strlen(sun.sun_path+1)) < 0) {

			perror("rtacct: bind");

			exit(-1);

		}

		if (listen(fd, 5) < 0) {

			perror("rtacct: listen");

			exit(-1);

		}

		if (daemon(0, 0)) {

			perror("rtacct: daemon");

			exit(-1);

		}

		signal(SIGPIPE, SIG_IGN);

		signal(SIGCHLD, sigchild);

		server_loop(fd);

		exit(0);

	}

	if (getenv("RTACCT_HISTORY"))

		snprintf(hist_name, sizeof(hist_name), "%s", getenv("RTACCT_HISTORY"));

	else

		sprintf(hist_name, "/tmp/.rtacct.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("rtacct: open history file");

			exit(-1);

		}

		if (flock(fd, LOCK_EX)) {

			perror("rtacct: flock history file");

			exit(-1);

		}

		if (fstat(fd, &stb) != 0) {

			perror("rtacct: fstat history file");

			exit(-1);

		}

		if (stb.st_nlink != 1 || stb.st_uid != getuid()) {

			fprintf(stderr, "rtacct: something is so wrong with history file, that I prefer not to proceed.\n");

			exit(-1);

		}

		if (stb.st_size != sizeof(*hist_db))

			if (write(fd, kern_db, sizeof(*hist_db)) < 0) {

				perror("rtacct: write history file");

				exit(-1);

			}

		hist_db = mmap(NULL, sizeof(*hist_db),

			       PROT_READ|PROT_WRITE,

			       no_update ? MAP_PRIVATE : MAP_SHARED,

			       fd, 0);

		if ((unsigned long)hist_db == ~0UL) {

			perror("mmap");

			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, "rtacct: history is aged out, resetting\n");

				memset(hist_db, 0, sizeof(*hist_db));

			}

		}

		close(fd);

	}

	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, "rtacct0"),

		 connect(fd, (struct sockaddr *)&sun, 2+1+strlen(sun.sun_path+1)) == 0))

	    && verify_forging(fd) == 0) {

		nread(fd, (char *)kern_db, sizeof(*kern_db));

		if (hist_db && hist_db->signature[0] &&

		    strcmp(kern_db->signature, hist_db->signature)) {

			fprintf(stderr, "rtacct: history is stale, ignoring it.\n");

			hist_db = NULL;

		}

		close(fd);

	} else {

		if (fd >= 0)

			close(fd);

		if (hist_db && hist_db->signature[0] &&

		    strcmp(hist_db->signature, "kernel")) {

			fprintf(stderr, "rtacct: history is stale, ignoring it.\n");

			hist_db = NULL;

		}

		pad_kern_table(kern_db, read_kern_table(kern_db->ival));

		strcpy(kern_db->signature, "kernel");

	}

	if (ignore_history || hist_db == NULL)

		dump_abs_db(stdout);

	else

		dump_incr_db(stdout);

	exit(0);

}