/* vi: set sw=4 ts=4: */
/*
 * Mini netstat implementation(s) for busybox
 * based in part on the netstat implementation from net-tools.
 *
 * Copyright (C) 2001 by Bart Visscher <magick@linux-fan.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <signal.h>
#include <errno.h>
#include <sys/stat.h>
#include <dirent.h>
#include <unistd.h>
#include <pwd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include "busybox.h"

#define NETSTAT_CONNECTED	0x01
#define NETSTAT_LISTENING	0x02
#define NETSTAT_NUMERIC		0x04
#define NETSTAT_TCP			0x10
#define NETSTAT_UDP			0x20
#define NETSTAT_RAW			0x40
#define NETSTAT_UNIX		0x80

int flags = NETSTAT_CONNECTED | 
			NETSTAT_TCP | NETSTAT_UDP | NETSTAT_RAW | NETSTAT_UNIX;

#define PROGNAME_WIDTHs PROGNAME_WIDTH1(PROGNAME_WIDTH)
#define PROGNAME_WIDTH1(s) PROGNAME_WIDTH2(s)
#define PROGNAME_WIDTH2(s) #s

#define PRG_HASH_SIZE 211

enum {
    TCP_ESTABLISHED = 1,
    TCP_SYN_SENT,
    TCP_SYN_RECV,
    TCP_FIN_WAIT1,
    TCP_FIN_WAIT2,
    TCP_TIME_WAIT,
    TCP_CLOSE,
    TCP_CLOSE_WAIT,
    TCP_LAST_ACK,
    TCP_LISTEN,
    TCP_CLOSING			/* now a valid state */
};

static const char *tcp_state[] =
{
    "",
    "ESTABLISHED",
    "SYN_SENT",
    "SYN_RECV",
    "FIN_WAIT1",
    "FIN_WAIT2",
    "TIME_WAIT",
    "CLOSE",
    "CLOSE_WAIT",
    "LAST_ACK",
    "LISTEN",
    "CLOSING"
};

typedef enum {
    SS_FREE = 0,		/* not allocated                */
    SS_UNCONNECTED,		/* unconnected to any socket    */
    SS_CONNECTING,		/* in process of connecting     */
    SS_CONNECTED,		/* connected to socket          */
    SS_DISCONNECTING		/* in process of disconnecting  */
} socket_state;

#define SO_ACCEPTCON    (1<<16)	/* performed a listen           */
#define SO_WAITDATA     (1<<17)	/* wait data to read            */
#define SO_NOSPACE      (1<<18)	/* no space to write            */

char *itoa(unsigned int i)
{
	/* 21 digits plus null terminator, good for 64-bit or smaller ints */
	static char local[22];
	char *p = &local[21];
	*p-- = '\0';
	do {
		*p-- = '0' + i % 10;
		i /= 10;
	} while (i > 0);
	return p + 1;
}

char *inet_sprint(struct sockaddr* addr, int num)
{
	char *str;
	str=inet_ntoa(((struct sockaddr_in*)addr)->sin_addr);
	if (!strcmp(str,"0.0.0.0")) {
		str="*";
	}
	if (num)
	{
	} else {
		struct hostent *he=gethostbyaddr(&((struct sockaddr_in*)addr)->sin_addr,4,AF_INET);
		if (he)
			str=he->h_name;
	}
	return str;
}

char *get_sname(int port, const char *proto, int num)
{
	char *str=itoa(ntohs(port));
	if (num) {
	} else {
		struct servent *se=getservbyport(port,proto);
		if (se)
			str=se->s_name;
	}
	if (!port) {
		str="*";
	}
	return str;
}

void snprint_ip_port(char *ip_port, int size, struct sockaddr *addr, int port, char *proto, int numeric)
{
	char *port_name;
	safe_strncpy(ip_port, inet_sprint(addr, numeric), size);
	port_name=get_sname(htons(port), proto, numeric);
	if ((strlen(ip_port) + strlen(port_name)) > 22)
		ip_port[22 - strlen(port_name)] = '\0';
	ip_port+=strlen(ip_port);
	strcat(ip_port, ":");
	strcat(ip_port, port_name);
}

static void tcp_do_one(int lnr, const char *line)
{
	char local_addr[64], rem_addr[64];
	char *state_str, more[512];
	int num, local_port, rem_port, d, state, timer_run, uid, timeout;
	struct sockaddr_in localaddr, remaddr;
	unsigned long rxq, txq, time_len, retr, inode;

	if (lnr == 0)
		return;

	more[0] = '\0';
	num = sscanf(line,
				 "%d: %64[0-9A-Fa-f]:%X %64[0-9A-Fa-f]:%X %X %lX:%lX %X:%lX %lX %d %d %ld %512s\n",
				 &d, local_addr, &local_port,
				 rem_addr, &rem_port, &state,
				 &txq, &rxq, &timer_run, &time_len, &retr, &uid, &timeout, &inode, more);

	if (strlen(local_addr) > 8) {
	} else {
		sscanf(local_addr, "%X",
			   &((struct sockaddr_in *) &localaddr)->sin_addr.s_addr);
		sscanf(rem_addr, "%X",
			   &((struct sockaddr_in *) &remaddr)->sin_addr.s_addr);
		((struct sockaddr *) &localaddr)->sa_family = AF_INET;
		((struct sockaddr *) &remaddr)->sa_family = AF_INET;
	}

	if (num < 10) {
		error_msg("warning, got bogus tcp line.\n");
		return;
	}
	state_str=(char*)tcp_state[state];
	if ((rem_port && (flags&NETSTAT_CONNECTED)) ||
		(!rem_port && (flags&NETSTAT_LISTENING)))
	{
		snprint_ip_port(local_addr, sizeof(local_addr),
						(struct sockaddr *) &localaddr, local_port,
						"tcp", flags&NETSTAT_NUMERIC);
						
		snprint_ip_port(rem_addr, sizeof(rem_addr),
						(struct sockaddr *) &remaddr, rem_port,
						"tcp", flags&NETSTAT_NUMERIC);

		printf("tcp   %6ld %6ld %-23s %-23s %-12s\n",
			   rxq, txq, local_addr, rem_addr, state_str);

	}
}

static void udp_do_one(int lnr, const char *line)
{
	char local_addr[64], rem_addr[64];
	char *state_str, more[512];
	int num, local_port, rem_port, d, state, timer_run, uid, timeout;
	struct sockaddr_in localaddr, remaddr;
	unsigned long rxq, txq, time_len, retr, inode;

	if (lnr == 0)
		return;

	more[0] = '\0';
	num = sscanf(line,
				 "%d: %64[0-9A-Fa-f]:%X %64[0-9A-Fa-f]:%X %X %lX:%lX %X:%lX %lX %d %d %ld %512s\n",
				 &d, local_addr, &local_port,
				 rem_addr, &rem_port, &state,
				 &txq, &rxq, &timer_run, &time_len, &retr, &uid, &timeout, &inode, more);

	if (strlen(local_addr) > 8) {
	} else {
		sscanf(local_addr, "%X",
			   &((struct sockaddr_in *) &localaddr)->sin_addr.s_addr);
		sscanf(rem_addr, "%X",
			   &((struct sockaddr_in *) &remaddr)->sin_addr.s_addr);
		((struct sockaddr *) &localaddr)->sa_family = AF_INET;
		((struct sockaddr *) &remaddr)->sa_family = AF_INET;
	}

	if (num < 10) {
		error_msg("warning, got bogus udp line.\n");
		return;
	}
	switch (state) {
		case TCP_ESTABLISHED:
			state_str = "ESTABLISHED";
			break;

		case TCP_CLOSE:
			state_str = "";
			break;

		default:
			state_str = "UNKNOWN";
			break;
	}

#define notnull(A) (A.sin_addr.s_addr)
	if ((notnull(remaddr) && (flags&NETSTAT_CONNECTED)) ||
		(!notnull(remaddr) && (flags&NETSTAT_LISTENING)))
	{
		snprint_ip_port(local_addr, sizeof(local_addr),
						(struct sockaddr *) &localaddr, local_port,
						"udp", flags&NETSTAT_NUMERIC);
						
		snprint_ip_port(rem_addr, sizeof(rem_addr),
						(struct sockaddr *) &remaddr, rem_port,
						"udp", flags&NETSTAT_NUMERIC);

		printf("udp   %6ld %6ld %-23s %-23s %-12s\n",
			   rxq, txq, local_addr, rem_addr, state_str);

	}
}

static void raw_do_one(int lnr, const char *line)
{
	char local_addr[64], rem_addr[64];
	char *state_str, more[512];
	int num, local_port, rem_port, d, state, timer_run, uid, timeout;
	struct sockaddr_in localaddr, remaddr;
	unsigned long rxq, txq, time_len, retr, inode;

	if (lnr == 0)
		return;

	more[0] = '\0';
	num = sscanf(line,
				 "%d: %64[0-9A-Fa-f]:%X %64[0-9A-Fa-f]:%X %X %lX:%lX %X:%lX %lX %d %d %ld %512s\n",
				 &d, local_addr, &local_port,
				 rem_addr, &rem_port, &state,
				 &txq, &rxq, &timer_run, &time_len, &retr, &uid, &timeout, &inode, more);

	if (strlen(local_addr) > 8) {
	} else {
		sscanf(local_addr, "%X",
			   &((struct sockaddr_in *) &localaddr)->sin_addr.s_addr);
		sscanf(rem_addr, "%X",
			   &((struct sockaddr_in *) &remaddr)->sin_addr.s_addr);
		((struct sockaddr *) &localaddr)->sa_family = AF_INET;
		((struct sockaddr *) &remaddr)->sa_family = AF_INET;
	}

	if (num < 10) {
		error_msg("warning, got bogus raw line.\n");
		return;
	}
	state_str=itoa(state);

#define notnull(A) (A.sin_addr.s_addr)
	if ((notnull(remaddr) && (flags&NETSTAT_CONNECTED)) ||
		(!notnull(remaddr) && (flags&NETSTAT_LISTENING)))
	{
		snprint_ip_port(local_addr, sizeof(local_addr),
						(struct sockaddr *) &localaddr, local_port,
						"raw", flags&NETSTAT_NUMERIC);
						
		snprint_ip_port(rem_addr, sizeof(rem_addr),
						(struct sockaddr *) &remaddr, rem_port,
						"raw", flags&NETSTAT_NUMERIC);

		printf("raw   %6ld %6ld %-23s %-23s %-12s\n",
			   rxq, txq, local_addr, rem_addr, state_str);

	}
}

#define HAS_INODE 1

static void unix_do_one(int nr, const char *line)
{
	static int has = 0;
	char path[PATH_MAX], ss_flags[32];
	char *ss_proto, *ss_state, *ss_type;
	int num, state, type, inode;
	void *d;
	unsigned long refcnt, proto, unix_flags;

	if (nr == 0) {
		if (strstr(line, "Inode"))
			has |= HAS_INODE;
		return;
	}
	path[0] = '\0';
	num = sscanf(line, "%p: %lX %lX %lX %X %X %d %s",
				 &d, &refcnt, &proto, &unix_flags, &type, &state, &inode, path);
	if (num < 6) {
		error_msg("warning, got bogus unix line.\n");
		return;
	}
	if (!(has & HAS_INODE))
		snprintf(path,sizeof(path),"%d",inode);

	if ((flags&(NETSTAT_LISTENING|NETSTAT_CONNECTED))!=(NETSTAT_LISTENING|NETSTAT_CONNECTED)) {
		if ((state == SS_UNCONNECTED) && (unix_flags & SO_ACCEPTCON)) {
			if (!(flags&NETSTAT_LISTENING))
				return;
		} else {
			if (!(flags&NETSTAT_CONNECTED))
				return;
		}
	}

	switch (proto) {
		case 0:
			ss_proto = "unix";
			break;

		default:
			ss_proto = "??";
	}

	switch (type) {
		case SOCK_STREAM:
			ss_type = "STREAM";
			break;

		case SOCK_DGRAM:
			ss_type = "DGRAM";
			break;

		case SOCK_RAW:
			ss_type = "RAW";
			break;

		case SOCK_RDM:
			ss_type = "RDM";
			break;

		case SOCK_SEQPACKET:
			ss_type = "SEQPACKET";
			break;

		default:
			ss_type = "UNKNOWN";
	}

	switch (state) {
		case SS_FREE:
			ss_state = "FREE";
			break;

		case SS_UNCONNECTED:
			/*
			 * Unconnected sockets may be listening
			 * for something.
			 */
			if (unix_flags & SO_ACCEPTCON) {
				ss_state = "LISTENING";
			} else {
				ss_state = "";
			}
			break;

		case SS_CONNECTING:
			ss_state = "CONNECTING";
			break;

		case SS_CONNECTED:
			ss_state = "CONNECTED";
			break;

		case SS_DISCONNECTING:
			ss_state = "DISCONNECTING";
			break;

		default:
			ss_state = "UNKNOWN";
	}

	strcpy(ss_flags, "[ ");
	if (unix_flags & SO_ACCEPTCON)
		strcat(ss_flags, "ACC ");
	if (unix_flags & SO_WAITDATA)
		strcat(ss_flags, "W ");
	if (unix_flags & SO_NOSPACE)
		strcat(ss_flags, "N ");

	strcat(ss_flags, "]");

	printf("%-5s %-6ld %-11s %-10s %-13s ",
		   ss_proto, refcnt, ss_flags, ss_type, ss_state);
	if (has & HAS_INODE)
		printf("%-6d ",inode);
	else
		printf("-      ");
	puts(path);
}

#define _PATH_PROCNET_UDP "/proc/net/udp"
#define _PATH_PROCNET_TCP "/proc/net/tcp"
#define _PATH_PROCNET_RAW "/proc/net/raw"
#define _PATH_PROCNET_UNIX "/proc/net/unix"

static int do_info(char *file, char *name, void (*proc)(int, const char *))
{
	char buffer[8192];
	int rc = 0;
	int lnr = 0;
	FILE *procinfo;

	procinfo = fopen((file), "r");
	if (procinfo == NULL) {
		if (errno != ENOENT) {
			perror((file));
			return -1;
		}
		error_msg("%s: no support for `%s' on this system.\n",
				"netstat", (name));
		rc = 1;
	} else {
		do {
			if (fgets(buffer, sizeof(buffer), procinfo))
				(proc)(lnr++, buffer);
		} while (!feof(procinfo));
		fclose(procinfo);
	}
	return rc;
}

/*
 * Our main function.
 */

int netstat_main(int argc, char **argv)
{
	int opt;
	int new_flags=0;
	while ((opt = getopt(argc, argv, "lantuwx")) != -1)
		switch (opt) {
		case 'l':
			flags &= ~NETSTAT_CONNECTED;
			flags |= NETSTAT_LISTENING;
			break;
		case 'a':
			flags |= NETSTAT_LISTENING | NETSTAT_CONNECTED;
			break;
		case 'n':
			flags |= NETSTAT_NUMERIC;
			break;
		case 't':
			new_flags |= NETSTAT_TCP;
			break;
		case 'u':
			new_flags |= NETSTAT_UDP;
			break;
		case 'w':
			new_flags |= NETSTAT_RAW;
			break;
		case 'x':
			new_flags |= NETSTAT_UNIX;
			break;
		default:
			show_usage();
		}
	if (new_flags) {
		flags &= ~(NETSTAT_TCP|NETSTAT_UDP|NETSTAT_RAW|NETSTAT_UNIX);
		flags |= new_flags;
	}
	if (flags&(NETSTAT_TCP|NETSTAT_UDP|NETSTAT_RAW)) {
		printf("Active Internet connections ");	/* xxx */

		if ((flags&(NETSTAT_LISTENING|NETSTAT_CONNECTED))==(NETSTAT_LISTENING|NETSTAT_CONNECTED))
			printf("(servers and established)");
		else {
			if (flags&NETSTAT_LISTENING)
				printf("(only servers)");
			else
				printf("(w/o servers)");
		}
		printf("\nProto Recv-Q Send-Q Local Address           Foreign Address         State      \n");
	}
	if (flags&NETSTAT_TCP)
		do_info(_PATH_PROCNET_TCP,"AF INET (tcp)",tcp_do_one);
	if (flags&NETSTAT_UDP)
		do_info(_PATH_PROCNET_UDP,"AF INET (udp)",udp_do_one);
	if (flags&NETSTAT_RAW)
		do_info(_PATH_PROCNET_RAW,"AF INET (raw)",raw_do_one);
	if (flags&NETSTAT_UNIX) {
		printf("Active UNIX domain sockets ");
		if ((flags&(NETSTAT_LISTENING|NETSTAT_CONNECTED))==(NETSTAT_LISTENING|NETSTAT_CONNECTED))
			printf("(servers and established)");
		else {
			if (flags&NETSTAT_LISTENING)
				printf("(only servers)");
			else
				printf("(w/o servers)");
		}

		printf("\nProto RefCnt Flags       Type       State         I-Node Path\n");
		do_info(_PATH_PROCNET_UNIX,"AF UNIX",unix_do_one);
	}
	return 0;
}