/* lnstat.c:  Unified linux network statistics

 *

 * Copyright (C) 2004 by Harald Welte <laforge@gnumonks.org>

 *

 * Development of this code was funded by Astaro AG, http://www.astaro.com/

 *

 * Based on original concept and ideas from predecessor rtstat.c:

 *

 * Copyright 2001 by Robert Olsson <robert.olsson@its.uu.se>

 *                                 Uppsala University, Sweden

 *

 * 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.

 *

 */

#include <unistd.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <dirent.h>

#include <limits.h>

#include <time.h>

#include <sys/time.h>

#include <sys/types.h>

#include "lnstat.h"

/* size of temp buffer used to read lines from procfiles */

#define FGETS_BUF_SIZE 1024

#define RTSTAT_COMPAT_LINE "entries  in_hit in_slow_tot in_no_route in_brd in_martian_dst in_martian_src  out_hit out_slow_tot out_slow_mc  gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n"

/* Read (and summarize for SMP) the different stats vars. */

static int scan_lines(struct lnstat_file *lf, int i)

{

	char buf[FGETS_BUF_SIZE];

	int j, num_lines = 0;

	for (j = 0; j < lf->num_fields; j++)

		lf->fields[j].values[i] = 0;

	rewind(lf->fp);

	/* skip first line */

	if (!lf->compat && !fgets(buf, sizeof(buf)-1, lf->fp))

		return -1;

	while (!feof(lf->fp) && fgets(buf, sizeof(buf)-1, lf->fp)) {

		char *ptr = buf;

		num_lines++;

		gettimeofday(&lf->last_read, NULL);

		for (j = 0; j < lf->num_fields; j++) {

			unsigned long f = strtoul(ptr, &ptr, 16);

			if (j == 0)

				lf->fields[j].values[i] = f;

			else

				lf->fields[j].values[i] += f;

		}

	}

	return num_lines;

}

static int time_after(struct timeval *last,

		      struct timeval *tout,

		      struct timeval *now)

{

	if (now->tv_sec > last->tv_sec + tout->tv_sec)

		return 1;

	if (now->tv_sec == last->tv_sec + tout->tv_sec) {

		if (now->tv_usec > last->tv_usec + tout->tv_usec)

			return 1;

	}

	return 0;

}

int lnstat_update(struct lnstat_file *lnstat_files)

{

	struct lnstat_file *lf;

	struct timeval tv;

	gettimeofday(&tv, NULL);

	for (lf = lnstat_files; lf; lf = lf->next) {

		if (time_after(&lf->last_read, &lf->interval, &tv)) {

			int i;

			struct lnstat_field *lfi;

			scan_lines(lf, 1);

			for (i = 0, lfi = &lf->fields[i];

			     i < lf->num_fields; i++, lfi = &lf->fields[i]) {

				if (i == 0)

					lfi->result = lfi->values[1];

				else

					lfi->result = (lfi->values[1]-lfi->values[0])

							/ lf->interval.tv_sec;

			}

			scan_lines(lf, 0);

		}

	}

	return 0;

}

/* scan first template line and fill in per-field data structures */

static int __lnstat_scan_fields(struct lnstat_file *lf, char *buf)

{

	char *tok;

	int i;

	tok = strtok(buf, " \t\n");

	for (i = 0; i < LNSTAT_MAX_FIELDS_PER_LINE; i++) {

		lf->fields[i].file = lf;

		strncpy(lf->fields[i].name, tok, LNSTAT_MAX_FIELD_NAME_LEN);

		/* has to be null-terminate since we initialize to zero

		 * and field size is NAME_LEN + 1 */

		tok = strtok(NULL, " \t\n");

		if (!tok) {

			lf->num_fields = i+1;

			return 0;

		}

	}

	return 0;

}

static int lnstat_scan_fields(struct lnstat_file *lf)

{

	char buf[FGETS_BUF_SIZE];

	rewind(lf->fp);

	if (!fgets(buf, sizeof(buf)-1, lf->fp))

		return -1;

	return __lnstat_scan_fields(lf, buf);

}

/* fake function emulating lnstat_scan_fields() for old kernels */

static int lnstat_scan_compat_rtstat_fields(struct lnstat_file *lf)

{

	char buf[FGETS_BUF_SIZE];

	strncpy(buf, RTSTAT_COMPAT_LINE, sizeof(buf) - 1);

	buf[sizeof(buf) - 1] = '\0';

	return __lnstat_scan_fields(lf, buf);

}

/* find out whether string 'name; is in given string array */

static int name_in_array(const int num, const char **arr, const char *name)

{

	int i;

	for (i = 0; i < num; i++) {

		if (!strcmp(arr[i], name))

			return 1;

	}

	return 0;

}

/* allocate lnstat_file and open given file */

static struct lnstat_file *alloc_and_open(const char *path, const char *file)

{

	struct lnstat_file *lf;

	/* allocate */

	lf = calloc(1, sizeof(*lf));

	if (!lf) {

		fprintf(stderr, "out of memory\n");

		return NULL;

	}

	/* initialize */

	snprintf(lf->basename, sizeof(lf->basename), "%s", file);

	snprintf(lf->path, sizeof(lf->path), "%s/%s", path, file);

	/* initialize to default */

	lf->interval.tv_sec = 1;

	/* open */

	lf->fp = fopen(lf->path, "r");

	if (!lf->fp) {

		perror(lf->path);

		free(lf);

		return NULL;

	}

	return lf;

}

/* lnstat_scan_dir - find and parse all available statistics files/fields */

struct lnstat_file *lnstat_scan_dir(const char *path, const int num_req_files,

				    const char **req_files)

{

	DIR *dir;

	struct lnstat_file *lnstat_files = NULL;

	struct dirent *de;

	if (!path)

		path = PROC_NET_STAT;

	dir = opendir(path);

	if (!dir) {

		struct lnstat_file *lf;

		/* Old kernel, before /proc/net/stat was introduced */

		fprintf(stderr, "Your kernel doesn't have lnstat support. ");

		/* we only support rtstat, not multiple files */

		if (num_req_files >= 2) {

			fputc('\n', stderr);

			return NULL;

		}

		/* we really only accept rt_cache */

		if (num_req_files && !name_in_array(num_req_files,

						    req_files, "rt_cache")) {

			fputc('\n', stderr);

			return NULL;

		}

		fprintf(stderr, "Fallback to old rtstat-only operation\n");

		lf = alloc_and_open("/proc/net", "rt_cache_stat");

		if (!lf)

			return NULL;

		lf->compat = 1;

		strncpy(lf->basename, "rt_cache", sizeof(lf->basename));

		/* FIXME: support for old files */

		if (lnstat_scan_compat_rtstat_fields(lf) < 0)

			return NULL;

		lf->next = lnstat_files;

		lnstat_files = lf;

		return lnstat_files;

	}

	while ((de = readdir(dir))) {

		struct lnstat_file *lf;

		if (de->d_type != DT_REG)

			continue;

		if (num_req_files && !name_in_array(num_req_files,

						    req_files, de->d_name))

			continue;

		lf = alloc_and_open(path, de->d_name);

		if (!lf) {

			closedir(dir);

			return NULL;

		}

		/* fill in field structure */

		if (lnstat_scan_fields(lf) < 0) {

			closedir(dir);

			return NULL;

		}

		/* prepend to global list */

		lf->next = lnstat_files;

		lnstat_files = lf;

	}

	closedir(dir);

	return lnstat_files;

}

int lnstat_dump(FILE *outfd, struct lnstat_file *lnstat_files)

{

	struct lnstat_file *lf;

	for (lf = lnstat_files; lf; lf = lf->next) {

		int i;

		fprintf(outfd, "%s:\n", lf->path);

		for (i = 0; i < lf->num_fields; i++)

			fprintf(outfd, "\t%2u: %s\n", i+1, lf->fields[i].name);

	}

	return 0;

}

struct lnstat_field *lnstat_find_field(struct lnstat_file *lnstat_files,

				       const char *name)

{

	struct lnstat_file *lf;

	struct lnstat_field *ret = NULL;

	const char *colon = strchr(name, ':');

	char *file;

	const char *field;

	if (colon) {

		file = strndup(name, colon-name);

		field = colon+1;

	} else {

		file = NULL;

		field = name;

	}

	for (lf = lnstat_files; lf; lf = lf->next) {

		int i;

		if (file && strcmp(file, lf->basename))

			continue;

		for (i = 0; i < lf->num_fields; i++) {

			if (!strcmp(field, lf->fields[i].name)) {

				ret = &lf->fields[i];

				goto out;

			}

		}

	}

out:

	free(file);

	return ret;

}