Fixed mbtask ping problem

ChangeLog

@@ -4790,6 +4790,10 @@ v0.33.20        10-Feb-2002
 		hopefully prevent that mbcico will use too much bandwidth on
 		TCP/IP trafic.
 		Splitted no TCP settings in no IBN, no IFC and no ITN.
+		Improved the ping tests, better errorlogging and suppresion of
+		icmp replies that are not for mbtask. Better protected against
+		flood pings. This should fixes the problem that the internet
+		seemed down while it was available.
 
 	mbcico:
 		Fixed binkp driver to accept incoming unprotected sessions.

mbtask/mbtask.c

@@ -1248,14 +1248,7 @@ int main(int argc, char **argv)
                         signal(i, SIG_IGN);
         }
 
-	/*
+	init_pingsocket();
-	 *  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);
-	}
 
 	/*
 	 *  mbtask is setuid root, drop privileges to user mbse.

mbtask/ping.c

@@ -150,8 +150,7 @@ struct sockaddr_in      to;
  */
 int ping_send(struct in_addr addr)
 {
-	int			len;
+    int			len, sentlen;
-	int			isock;
 #ifdef __linux__
     struct icmp_filter	f;
 #else
@@ -169,8 +168,7 @@ int ping_send(struct in_addr addr)
     SOL_IP = pe->p_proto;
 #endif
 
-	isock = ping_isocket;
+    p_sequence++;
-	p_sequence = 1;
     id = (unsigned short)get_rand16(); /* randomize a ping id */
 
 #ifdef __linux__
@@ -181,9 +179,9 @@ int ping_send(struct in_addr addr)
     /* 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 (setsockopt(ping_isocket, SOL_RAW, ICMP_FILTER, &f, sizeof(f)) == -1) {
 	if (icmp_errs < ICMP_MAX_ERRS)
-			tasklog('?', "$icmp ping: setsockopt() failed %d", isock);
+	    tasklog('?', "$icmp ping: setsockopt() failed %d", ping_isocket);
 	return -1;
     }
 #endif
@@ -211,7 +209,10 @@ int ping_send(struct in_addr addr)
     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) {
+
+    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;
@@ -219,10 +220,19 @@ int ping_send(struct in_addr addr)
 
 
 
+/*
+ *  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;
@@ -230,10 +240,9 @@ int ping_receive(struct in_addr addr)
     socklen_t           sl;        
     struct pollfd       pfd;
 
-	isock = ping_isocket;
+    pfd.fd = ping_isocket;
-
-	pfd.fd = isock;
     pfd.events = POLLIN;
+
     /*
      *  10 mSec is enough, this function is called at regular intervals.
      */
@@ -245,24 +254,28 @@ int ping_receive(struct in_addr addr)
 
     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 = 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 && 
+		    if (iph.ip_saddr == addr.s_addr && icmpp.icmp_type == ICMP_ECHOREPLY &&
-					    icmpp.icmp_type == ICMP_ECHOREPLY &&
+			ntohs(icmpp.icmp_id) == id && ntohs(icmpp.icmp_seq) == p_sequence) {
-					    ntohs(icmpp.icmp_id) == id && 
+//			tasklog('-', "ping: valid reply received, id %d, sequence %d", ntohs(icmpp.icmp_id), ntohs(icmpp.icmp_seq));
-					    ntohs(icmpp.icmp_seq) <= p_sequence) {
 			return 0;
 		    } else {
 			/* No regular echo reply. Maybe an error? */
-						if (icmp4_errcmp((char *)&icmpd, ICMP4_ECHO_LEN, 
+			if (icmp4_errcmp((char *)&icmpd, ICMP4_ECHO_LEN, &to.sin_addr, buf, len, ICMP_DEST_UNREACH))
-						    &to.sin_addr, buf, len, ICMP_DEST_UNREACH) ||
+			    return -2;
-						    icmp4_errcmp((char *)&icmpd, ICMP4_ECHO_LEN, 
+			if (icmp4_errcmp((char *)&icmpd, ICMP4_ECHO_LEN, &to.sin_addr, buf, len, ICMP_TIME_EXCEEDED))
-						    &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;
 		    }
 		}
 	    }
@@ -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);
+    }
+}
+
+

mbtask/ping.h

@@ -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