474 lines
12 KiB
C
474 lines
12 KiB
C
/*****************************************************************************
|
|
*
|
|
* $Id$
|
|
* Purpose ...............: mbtask - ping functions
|
|
*
|
|
*****************************************************************************
|
|
* Copyright (C) 1997-2003
|
|
*
|
|
* Michiel Broek FIDO: 2:280/2802
|
|
* Beekmansbos 10
|
|
* 1971 BV IJmuiden
|
|
* the Netherlands
|
|
*
|
|
* This file is part of MBSE BBS.
|
|
*
|
|
* This BBS 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, or (at your option) any
|
|
* later version.
|
|
*
|
|
* MBSE BBS 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 MBSE BBS; see the file COPYING. If not, write to the Free
|
|
* Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*****************************************************************************/
|
|
|
|
#include "../config.h"
|
|
#include "libs.h"
|
|
#include "../lib/structs.h"
|
|
#include "../lib/mberrors.h"
|
|
#include "taskstat.h"
|
|
#include "taskutil.h"
|
|
#include "ping.h"
|
|
|
|
|
|
|
|
/*
|
|
* Global variables
|
|
*/
|
|
extern struct taskrec TCFG; /* Task config record */
|
|
int ping_isocket; /* Ping socket */
|
|
int icmp_errs = 0; /* ICMP error counter */
|
|
extern int internet; /* Internet is down */
|
|
extern int rescan; /* Master rescan flag */
|
|
struct in_addr paddr; /* Current ping address */
|
|
extern int T_Shutdown; /* Program shutdown */
|
|
int ping_run = FALSE; /* Thread runnning */
|
|
|
|
|
|
|
|
/*
|
|
* Internal prototypes
|
|
*/
|
|
static int icmp4_errcmp(char *, int, struct in_addr *, char *, int, int);
|
|
unsigned short get_rand16(void);
|
|
int ping_send(struct in_addr);
|
|
int ping_receive(struct in_addr);
|
|
|
|
|
|
/*
|
|
* different names, same thing... be careful, as these are macros...
|
|
*/
|
|
#if defined(__FreeBSD__) || defined(__NetBSD__)
|
|
# define icmphdr icmp
|
|
# define iphdr ip
|
|
# define ip_saddr ip_src.s_addr
|
|
# define ip_daddr ip_dst.s_addr
|
|
#else
|
|
# define ip_saddr saddr
|
|
# define ip_daddr daddr
|
|
# define ip_hl ihl
|
|
# define ip_p protocol
|
|
#endif
|
|
|
|
|
|
#ifdef __linux__
|
|
# define icmp_type type
|
|
# define icmp_code code
|
|
# define icmp_cksum checksum
|
|
# ifdef icmp_id
|
|
# undef icmp_id
|
|
# endif
|
|
# define icmp_id un.echo.id
|
|
# ifdef icmp_seq
|
|
# undef icmp_seq
|
|
# endif
|
|
# define icmp_seq un.echo.sequence
|
|
#endif
|
|
|
|
#if defined(__FreeBSD__) || defined(__NetBSD__)
|
|
# define ICMP_DEST_UNREACH ICMP_UNREACH
|
|
# define ICMP_TIME_EXCEEDED ICMP_TIMXCEED
|
|
#endif
|
|
|
|
#define ICMP_BASEHDR_LEN 8
|
|
#define ICMP4_ECHO_LEN ICMP_BASEHDR_LEN
|
|
|
|
|
|
short p_sequence = 10;
|
|
unsigned short id;
|
|
struct icmphdr icmpd;
|
|
struct sockaddr_in to;
|
|
|
|
|
|
|
|
/*
|
|
* Takes a packet as send out and a recieved ICMP packet and looks whether the ICMP packet is
|
|
* an error reply on the sent-out one. packet is only the packet (without IP header).
|
|
* errmsg includes an IP header.
|
|
* to is the destination address of the original packet (the only thing that is actually
|
|
* compared of the IP header). The RFC sais that we get at least 8 bytes of the offending packet.
|
|
* We do not compare more, as this is all we need.
|
|
*/
|
|
static int icmp4_errcmp(char *packet, int plen, struct in_addr *too, char *errmsg, int elen, int errtype)
|
|
{
|
|
struct iphdr iph;
|
|
struct icmphdr icmph;
|
|
struct iphdr eiph;
|
|
char *data;
|
|
|
|
/*
|
|
* lots of memcpy to avoid unaligned accesses on alpha
|
|
*/
|
|
if (elen < sizeof(struct iphdr))
|
|
return 0;
|
|
|
|
memcpy(&iph, errmsg, sizeof(iph));
|
|
if (iph.ip_p != IPPROTO_ICMP || elen < iph.ip_hl * 4 + ICMP_BASEHDR_LEN + sizeof(eiph))
|
|
return 0;
|
|
|
|
memcpy(&icmph, errmsg + iph.ip_hl * 4, ICMP_BASEHDR_LEN);
|
|
memcpy(&eiph, errmsg + iph.ip_hl * 4 + ICMP_BASEHDR_LEN, sizeof(eiph));
|
|
if (elen < iph.ip_hl * 4 + ICMP_BASEHDR_LEN + eiph.ip_hl * 4 + 8)
|
|
return 0;
|
|
|
|
data = errmsg + iph.ip_hl * 4 + ICMP_BASEHDR_LEN + eiph.ip_hl * 4;
|
|
return icmph.icmp_type == errtype && memcmp(&too->s_addr, &eiph.ip_daddr, sizeof(too->s_addr)) == 0 &&
|
|
memcmp(data, packet, plen < 8 ?plen:8) == 0;
|
|
}
|
|
|
|
|
|
|
|
unsigned short get_rand16(void)
|
|
{
|
|
return random()&0xffff;
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
* IPv4/ICMPv4 ping. Called from ping (see below)
|
|
*/
|
|
int ping_send(struct in_addr addr)
|
|
{
|
|
int len, sentlen;
|
|
#ifdef __linux__
|
|
struct icmp_filter f;
|
|
#else
|
|
struct protoent *pe;
|
|
int SOL_IP;
|
|
#endif
|
|
unsigned long sum;
|
|
unsigned short *ptr;
|
|
|
|
#ifndef __linux__
|
|
if (!(pe = getprotobyname("ip"))) {
|
|
Syslog('?', "icmp ping: getprotobyname() failed: %s", strerror(errno));
|
|
return -1;
|
|
}
|
|
SOL_IP = pe->p_proto;
|
|
#endif
|
|
|
|
id = (unsigned short)get_rand16(); /* randomize a ping id */
|
|
|
|
#ifdef __linux__
|
|
/*
|
|
* Fancy ICMP filering -- only on Linux (as far is I know)
|
|
*
|
|
* In fact, there should be macros for treating icmp_filter, but I haven't found them in Linux 2.2.15.
|
|
* So, set it manually and unportable ;-)
|
|
* This filter lets ECHO_REPLY (0), DEST_UNREACH(3) and TIME_EXCEEDED(11) pass.
|
|
* !(0000 1000 0000 1001) = 0xff ff f7 f6
|
|
*/
|
|
f.data=0xfffff7f6;
|
|
if (setsockopt(ping_isocket, SOL_RAW, ICMP_FILTER, &f, sizeof(f)) == -1) {
|
|
if (icmp_errs < ICMP_MAX_ERRS)
|
|
Syslog('?', "$icmp ping: setsockopt() failed %d", ping_isocket);
|
|
return -1;
|
|
}
|
|
#endif
|
|
|
|
icmpd.icmp_type = ICMP_ECHO;
|
|
icmpd.icmp_code = 0;
|
|
icmpd.icmp_cksum = 0;
|
|
icmpd.icmp_id = htons((short)id);
|
|
icmpd.icmp_seq = htons(p_sequence);
|
|
|
|
/* Checksumming - Algorithm taken from nmap. Thanks... */
|
|
|
|
ptr = (unsigned short *)&icmpd;
|
|
sum = 0;
|
|
|
|
for (len = 0; len < 4; len++) {
|
|
sum += *ptr++;
|
|
}
|
|
sum = (sum >> 16) + (sum & 0xffff);
|
|
sum += (sum >> 16);
|
|
icmpd.icmp_cksum = ~sum;
|
|
|
|
memset(&to, 0, sizeof(to));
|
|
to.sin_family = AF_INET;
|
|
to.sin_port = 0;
|
|
to.sin_addr = addr;
|
|
SET_SOCKA_LEN4(to);
|
|
|
|
sentlen = sendto(ping_isocket, &icmpd, ICMP4_ECHO_LEN, 0, (struct sockaddr *)&to, sizeof(to));
|
|
if (sentlen != ICMP4_ECHO_LEN) {
|
|
if (icmp_errs < ICMP_MAX_ERRS) {
|
|
if (sentlen == -1)
|
|
Syslog('+', "ping: sent error: %s", strerror(errno));
|
|
else
|
|
Syslog('+', "ping: sent %d octets, ret %d", ICMP4_ECHO_LEN, sentlen);
|
|
}
|
|
return -2;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
* 0 = reply received Ok.
|
|
* -1 = reply packet not for us, this is Ok.
|
|
* -2 = destination unreachable.
|
|
* -3 = poll/select error.
|
|
* -4 = time exceeded.
|
|
* -5 = wrong packetlen received.
|
|
* -6 = no data received, this is Ok.
|
|
* -7 = icmp parameter problem.
|
|
*/
|
|
int ping_receive(struct in_addr addr)
|
|
{
|
|
char buf[1024];
|
|
int rc, len;
|
|
struct sockaddr_in ffrom;
|
|
struct icmphdr icmpp;
|
|
struct iphdr iph;
|
|
socklen_t sl;
|
|
struct pollfd pfd;
|
|
|
|
pfd.fd = ping_isocket;
|
|
pfd.events = POLLIN;
|
|
pfd.revents = 0;
|
|
|
|
/*
|
|
* 100 mSec is enough, this function is called at regular intervals.
|
|
*/
|
|
if ((rc = poll(&pfd, 1, 100) < 0)) {
|
|
if (icmp_errs < ICMP_MAX_ERRS)
|
|
Syslog('?', "$poll/select failed");
|
|
return -3;
|
|
}
|
|
// Syslog('p', "poll_thread: poll interrupted rc=%d events=%04x", rc, pfd.revents);
|
|
|
|
if (pfd.revents & POLLIN || pfd.revents & POLLERR || pfd.revents & POLLHUP || pfd.revents & POLLNVAL) {
|
|
sl = sizeof(ffrom);
|
|
if ((len = recvfrom(ping_isocket, &buf, sizeof(buf)-1, 0,(struct sockaddr *)&ffrom, &sl)) != -1) {
|
|
if (len > sizeof(struct iphdr)) {
|
|
memcpy(&iph, buf, sizeof(iph));
|
|
if (len - iph.ip_hl * 4 >= ICMP_BASEHDR_LEN) {
|
|
memcpy(&icmpp, ((unsigned long int *)buf)+iph.ip_hl, sizeof(icmpp));
|
|
if (iph.ip_saddr == addr.s_addr && icmpp.icmp_type == ICMP_ECHOREPLY &&
|
|
ntohs(icmpp.icmp_id) == id && ntohs(icmpp.icmp_seq) == p_sequence) {
|
|
return 0;
|
|
} else {
|
|
/* No regular echo reply. Maybe an error? */
|
|
if (icmp4_errcmp((char *)&icmpd, ICMP4_ECHO_LEN, &to.sin_addr, buf, len, ICMP_DEST_UNREACH))
|
|
return -2;
|
|
if (icmp4_errcmp((char *)&icmpd, ICMP4_ECHO_LEN, &to.sin_addr, buf, len, ICMP_TIME_EXCEEDED))
|
|
return -4;
|
|
#ifdef __linux__
|
|
if (icmp4_errcmp((char *)&icmpd, ICMP4_ECHO_LEN, &to.sin_addr, buf, len, ICMP_PARAMETERPROB))
|
|
return -7;
|
|
#endif
|
|
/*
|
|
* No fatal problem, the return code will be -1 caused by other
|
|
* icmp trafic on the network (packets not for us).
|
|
*/
|
|
return -1;
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
return -5; /* error */
|
|
}
|
|
}
|
|
return -6; /* no answer */
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
* Create the ping socket, called from main() during init as root.
|
|
*/
|
|
void init_pingsocket(void)
|
|
{
|
|
if ((ping_isocket = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP)) == -1) {
|
|
if (errno == EPERM) {
|
|
fprintf(stderr, "socket init failed, mbtask not installed setuid root\n");
|
|
} else {
|
|
fprintf(stderr, "socket init failed\n");
|
|
}
|
|
exit(MBERR_INIT_ERROR);
|
|
}
|
|
|
|
/*
|
|
* If someone's messing with us, bail.
|
|
* It would be nice to issue an error message, but to where?
|
|
*/
|
|
if (ping_isocket == STDIN_FILENO || ping_isocket == STDOUT_FILENO || ping_isocket == STDERR_FILENO) {
|
|
exit(MBERR_GENERAL);
|
|
}
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
* Ping thread
|
|
*/
|
|
void *ping_thread(void)
|
|
{
|
|
int rc = 0;
|
|
static int pingnr, pingresult[2];
|
|
static char pingaddress[41];
|
|
static time_t pingsend;
|
|
time_t now;
|
|
|
|
Syslog('+', "Starting ping thread");
|
|
pingresult[1] = pingresult[2] = FALSE;
|
|
pingnr = 2;
|
|
internet = FALSE;
|
|
ping_run = TRUE;
|
|
|
|
while (! T_Shutdown) {
|
|
|
|
#ifdef USE_EXPERMIMENT
|
|
Syslog('p', "ping_thread loop start");
|
|
#endif
|
|
/*
|
|
* Select new address to ping
|
|
*/
|
|
if (pingnr == 1) {
|
|
pingnr = 2;
|
|
if (strlen(TCFG.isp_ping2)) {
|
|
sprintf(pingaddress, "%s", TCFG.isp_ping2);
|
|
} else {
|
|
pingresult[2] = FALSE;
|
|
}
|
|
} else {
|
|
pingnr = 1;
|
|
if (strlen(TCFG.isp_ping1)) {
|
|
sprintf(pingaddress, "%s", TCFG.isp_ping1);
|
|
} else {
|
|
pingresult[1] = FALSE;
|
|
}
|
|
}
|
|
|
|
if (inet_aton(pingaddress, &paddr)) {
|
|
rc = ping_send(paddr);
|
|
#ifdef USE_EXPERIMENT
|
|
Syslog('p', "ping_send(%s) rc=%d", pingaddress, rc);
|
|
#endif
|
|
if (rc) {
|
|
if (icmp_errs++ < ICMP_MAX_ERRS)
|
|
Syslog('?', "ping: to %s rc=%d", pingaddress, rc);
|
|
pingresult[pingnr] = FALSE;
|
|
now = time(NULL) + 10;
|
|
|
|
while ((! T_Shutdown) && (time(NULL) < now)) {
|
|
sleep(1);
|
|
}
|
|
if (T_Shutdown)
|
|
break;
|
|
} else {
|
|
pingsend = time(NULL);
|
|
|
|
while (TRUE) {
|
|
if (T_Shutdown)
|
|
break;
|
|
|
|
if (time(NULL) >= (pingsend + 20)) {
|
|
pingresult[pingnr] = FALSE;
|
|
if (icmp_errs < ICMP_MAX_ERRS)
|
|
Syslog('?', "ping: to %s timeout", pingaddress);
|
|
break;
|
|
} else {
|
|
/*
|
|
* Quickly eat all packets not for us, we only want our
|
|
* packets and empty results (packet still underway).
|
|
*/
|
|
while ((rc = ping_receive(paddr)) == -1);
|
|
#ifdef USE_EXPERIMENT
|
|
Syslog('p', "ping_receive() rc=%d", rc);
|
|
#endif
|
|
if (!rc) {
|
|
/*
|
|
* Reply received.
|
|
*/
|
|
rc = time(NULL) - pingsend;
|
|
if (rc > 5)
|
|
Syslog('+', "Ping: slow reply after %d seconds", rc);
|
|
pingresult[pingnr] = TRUE;
|
|
now = time(NULL) + 20 - rc;
|
|
while ((! T_Shutdown) && (time(NULL) < now)) {
|
|
sleep(1);
|
|
}
|
|
break;
|
|
} else {
|
|
if (rc != -6) {
|
|
Syslog('p', "ping: recv %s id=%d rc=%d", pingaddress, id, rc);
|
|
pingresult[pingnr] = FALSE;
|
|
}
|
|
}
|
|
}
|
|
} /* while TRUE */
|
|
}
|
|
} else {
|
|
if (icmp_errs++ < ICMP_MAX_ERRS)
|
|
Syslog('?', "Ping address %d is invalid \"%s\"", pingnr, pingaddress);
|
|
now = time(NULL) + 10;
|
|
while ((! T_Shutdown) && (time(NULL) < now)) {
|
|
sleep(1);
|
|
}
|
|
}
|
|
|
|
if (T_Shutdown)
|
|
break;
|
|
|
|
/*
|
|
* Evaluate the result of the ping test
|
|
*/
|
|
if (pingresult[1] == FALSE && pingresult[2] == FALSE) {
|
|
icmp_errs++;
|
|
if (internet) {
|
|
Syslog('!', "Internet connection is down");
|
|
internet = FALSE;
|
|
sem_set((char *)"scanout", TRUE);
|
|
RemoveSema((char *)"is_inet");
|
|
rescan = TRUE;
|
|
}
|
|
} else {
|
|
icmp_errs = 0;
|
|
if (!internet) {
|
|
Syslog('!', "Internet connection is up");
|
|
internet = TRUE;
|
|
sem_set((char *)"scanout", TRUE);
|
|
CreateSema((char *)"is_inet");
|
|
rescan = TRUE;
|
|
}
|
|
}
|
|
}
|
|
|
|
ping_run = FALSE;
|
|
Syslog('+', "Ping thread stopped");
|
|
pthread_exit(NULL);
|
|
}
|
|
|
|
|
|
|