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Fixed mbtask ping problem

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This commit is contained in:
Michiel Broek
2002-05-04 16:05:48 +00:00
parent e8b82ff59c
commit f8e9d28fda
4 changed files with 146 additions and 107 deletions
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9
mbtask/mbtask.c
View File

@@ -1248,14 +1248,7 @@ int main(int argc, char **argv)
signal(i, SIG_IGN);
}
/*
* Create the ping socket while we are still root.
*/
if ((ping_isocket = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP)) == -1) {
perror("");
printf("socket init failed, is mbtask not installed setuid root?\n");
exit(1);
}
init_pingsocket();
/*
* mbtask is setuid root, drop privileges to user mbse.

236
mbtask/ping.c
View File

@@ -150,134 +150,147 @@ struct sockaddr_in to;
*/
int ping_send(struct in_addr addr)
{
int len;
int isock;
int len, sentlen;
#ifdef __linux__
struct icmp_filter f;
struct icmp_filter f;
#else
struct protoent *pe;
int SOL_IP;
struct protoent *pe;
int SOL_IP;
#endif
unsigned long sum;
unsigned short *ptr;
unsigned long sum;
unsigned short *ptr;
#ifndef __linux__
if (!(pe = getprotobyname("ip"))) {
tasklog('?', "icmp ping: getprotobyname() failed: %s", strerror(errno));
return -1;
}
SOL_IP = pe->p_proto;
if (!(pe = getprotobyname("ip"))) {
tasklog('?', "icmp ping: getprotobyname() failed: %s", strerror(errno));
return -1;
}
SOL_IP = pe->p_proto;
#endif
isock = ping_isocket;
p_sequence = 1;
id = (unsigned short)get_rand16(); /* randomize a ping id */
p_sequence++;
id = (unsigned short)get_rand16(); /* randomize a ping id */
#ifdef __linux__
/* Fancy ICMP filering -- only on Linux (as far is I know) */
/* 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(isock, SOL_RAW, ICMP_FILTER, &f, sizeof(f)) == -1) {
if (icmp_errs < ICMP_MAX_ERRS)
tasklog('?', "$icmp ping: setsockopt() failed %d", isock);
return -1;
}
/* In fact, there should be macros for treating icmp_filter, but I haven't found them in Linux 2.2.15.
* So, set it manually and unportable ;-) */
/* This filter lets ECHO_REPLY (0), DEST_UNREACH(3) and TIME_EXCEEDED(11) pass. */
/* !(0000 1000 0000 1001) = 0xff ff f7 f6 */
f.data=0xfffff7f6;
if (setsockopt(ping_isocket, SOL_RAW, ICMP_FILTER, &f, sizeof(f)) == -1) {
if (icmp_errs < ICMP_MAX_ERRS)
tasklog('?', "$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);
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... */
/* Checksumming - Algorithm taken from nmap. Thanks... */
ptr = (unsigned short *)&icmpd;
sum = 0;
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;
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);
if (sendto(isock, &icmpd, ICMP4_ECHO_LEN, 0, (struct sockaddr *)&to, sizeof(to)) == -1) {
return -2;
}
return 0;
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) {
tasklog('+', "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 isock;
int len;
struct sockaddr_in ffrom;
struct icmphdr icmpp;
struct iphdr iph;
socklen_t sl;
struct pollfd pfd;
char buf[1024];
int len;
struct sockaddr_in ffrom;
struct icmphdr icmpp;
struct iphdr iph;
socklen_t sl;
struct pollfd pfd;
isock = ping_isocket;
pfd.fd = ping_isocket;
pfd.events = POLLIN;
pfd.fd = isock;
pfd.events = POLLIN;
/*
* 10 mSec is enough, this function is called at regular intervals.
*/
if (poll(&pfd, 1, 10) < 0) {
if (icmp_errs < ICMP_MAX_ERRS)
tasklog('?', "$poll/select failed");
return -3;
}
/*
* 10 mSec is enough, this function is called at regular intervals.
*/
if (poll(&pfd, 1, 10) < 0) {
if (icmp_errs < ICMP_MAX_ERRS)
tasklog('?', "$poll/select failed");
return -3;
}
if (pfd.revents & POLLIN || pfd.revents & POLLERR || pfd.revents & POLLHUP || pfd.revents & POLLNVAL) {
sl = sizeof(ffrom);
if ((len = recvfrom(isock, &buf, sizeof(buf), 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) ||
icmp4_errcmp((char *)&icmpd, ICMP4_ECHO_LEN,
&to.sin_addr, buf, len, ICMP_TIME_EXCEEDED)) {
return -4;
}
}
}
}
} else {
return -5; /* error */
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) {
// tasklog('-', "ping: valid reply received, id %d, sequence %d", ntohs(icmpp.icmp_id), ntohs(icmpp.icmp_seq));
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;
if (icmp4_errcmp((char *)&icmpd, ICMP4_ECHO_LEN, &to.sin_addr, buf, len, ICMP_PARAMETERPROB))
return -7;
/*
* 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 */
}
return -6; /* no answer */
}
void check_ping(void)
{
int rc;
int rc;
/*
* If the previous pingstat is still P_SENT, then we now consider it a timeout.
@@ -358,12 +371,16 @@ void state_ping(void)
switch (pingstate) {
case P_NONE: pingresult[pingnr] = TRUE;
break;
case P_SENT: rc = ping_receive(paddr);
case P_SENT: /*
* Quickly eat all packets not for us, we only want our
* packets and empty results (packet still underway).
*/
while ((rc = ping_receive(paddr)) == -1);
if (!rc) {
pingstate = P_OK;
pingresult[pingnr] = TRUE;
} else {
if (rc != -6)
// if (rc != -6)
tasklog('p', "ping recv %s id=%d rc=%d", pingaddress, id, rc);
}
break;
@@ -371,3 +388,28 @@ void state_ping(void)
}
/*
* Create the ping socket, called from main() durig 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(1);
}
/*
* 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(255);
}
}

4
mbtask/ping.h
View File

@@ -1,4 +1,4 @@
/* $Id */
/* $Id$ */
#ifndef _PING_H
#define _PING_H
@@ -17,6 +17,6 @@ typedef enum {P_INIT, P_SENT, P_FAIL, P_OK, P_ERROR, P_NONE} PINGSTATE;
void check_ping(void);
void state_ping(void);
void init_pingsocket(void);
#endif