[src/trunk]: src/usr.sbin/traceroute Fix use of -I and -P at the same time by...

[sommerfeld <sommerfeld%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b737a9529679
branches:  trunk
changeset: 481284:b737a9529679
user:      sommerfeld <sommerfeld%NetBSD.org@localhost>
date:      Tue Jan 25 16:24:32 2000 +0000

description:
Fix use of -I and -P at the same time by refactoring so there's only
one set of code which knows how to resize the packet.
Report when we shrink MTU because of an EMSGSIZE return; fix
formatting to let this not look ugly.
Add a few likely MTU's to the table (1480 and 1280).

diffstat:

 usr.sbin/traceroute/traceroute.c |  50 ++++++++++++++++++++++++++++-----------
 1 files changed, 36 insertions(+), 14 deletions(-)

diffs (133 lines):

diff -r 666036faac0f -r b737a9529679 usr.sbin/traceroute/traceroute.c
--- a/usr.sbin/traceroute/traceroute.c  Tue Jan 25 16:07:13 2000 +0000
+++ b/usr.sbin/traceroute/traceroute.c  Tue Jan 25 16:24:32 2000 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: traceroute.c,v 1.37 1999/09/03 03:10:38 itojun Exp $   */
+/*     $NetBSD: traceroute.c,v 1.38 2000/01/25 16:24:32 sommerfeld Exp $       */
 
 /*
  * Copyright (c) 1988, 1989, 1991, 1994, 1995, 1996, 1997
@@ -29,7 +29,7 @@
 #else
 __COPYRIGHT("@(#) Copyright (c) 1988, 1989, 1991, 1994, 1995, 1996, 1997\n\
 The Regents of the University of California.  All rights reserved.\n");
-__RCSID("$NetBSD: traceroute.c,v 1.37 1999/09/03 03:10:38 itojun Exp $");
+__RCSID("$NetBSD: traceroute.c,v 1.38 2000/01/25 16:24:32 sommerfeld Exp $");
 #endif
 #endif
 
@@ -291,6 +291,7 @@
 int packlen;                   /* total length of packet */
 int minpacket;                 /* min ip packet size */
 int maxpacket = 32 * 1024;     /* max ip packet size */
+int printed_ttl = 0;
 
 char *prog;
 char *source;
@@ -326,6 +327,8 @@
          1536,  
          1500,  
          1492,
+        1480,
+        1280,
          1006,
           576,
           552,
@@ -355,6 +358,7 @@
 int    packet_ok(u_char *, int, struct sockaddr_in *, int);
 char   *pr_type(u_char);
 void   print(u_char *, int, struct sockaddr_in *);
+void   resize_packet(void);
 void   dump_packet(void);
 void   send_probe(int, int, struct timeval *);
 void   setsin(struct sockaddr_in *, u_int32_t);
@@ -890,7 +894,7 @@
                int unreachable = 0;
 
 again:
-               Printf("%2d ", ttl);
+               printed_ttl = 0;
                for (probe = 0; probe < nprobes; ++probe) {
                        register int cc;
                        struct timeval t1, t2;
@@ -1064,6 +1068,7 @@
        register int cc;
        register struct udpiphdr * ui;
        struct ip tip;
+       int oldmtu = packlen;
 
 again:
 #ifdef BYTESWAP_IP_LEN
@@ -1173,21 +1178,16 @@
                if (cc < 0) {
                        /*
                         * An errno of EMSGSIZE means we're writing too big a
-                        * datagram for the interface.  We have to just decrease
-                        * the packet size until we find one that works.
+                        * datagram for the interface.  We have to just
+                        * decrease the packet size until we find one that
+                        * works.
                         *
                         * XXX maybe we should try to read the outgoing if's 
                         * mtu?
                         */
-
                        if (errno == EMSGSIZE) {
                                packlen = *mtuptr++;
-               outudp->uh_ulen =
-                   htons((u_short)(packlen - (sizeof(*outip) + optlen)));
-#ifdef _NoLongerLooksUgly_
-                               Printf("message too big, "
-                                   "trying new MTU = %d\n", packlen);
-#endif
+                               resize_packet();
                                goto again;
                        } else
                                Fprintf(stderr, "%s: sendto: %s\n",
@@ -1198,6 +1198,16 @@
                    prog, hostname, packlen, cc);
                (void)fflush(stdout);
        }
+       if (oldmtu != packlen) {
+               Printf("message too big, "
+                   "trying new MTU = %d\n", packlen);
+               printed_ttl = 0;
+       }
+       if (!printed_ttl) {
+               Printf("%2d ", ttl);
+               printed_ttl = 1;
+       }
+       
 }
 
 double
@@ -1305,6 +1315,19 @@
        return(0);
 }
 
+void resize_packet(void)
+{
+       if (useicmp) {
+               outicmp->icmp_cksum = 0;
+               outicmp->icmp_cksum = in_cksum((u_short *)outicmp,
+                   packlen - (sizeof(*outip) + optlen));
+               if (outicmp->icmp_cksum == 0)
+                       outicmp->icmp_cksum = 0xffff;
+       } else {
+               outudp->uh_ulen =
+                   htons((u_short)(packlen - (sizeof(*outip) + optlen)));
+       }
+}
 
 void
 print(register u_char *buf, register int cc, register struct sockaddr_in *from)
@@ -1578,8 +1601,7 @@
                 packlen = *mtuptr++;
                Printf("Trying new MTU = %d\n", packlen);
         }
-       outudp->uh_ulen =
-           htons((u_short)(packlen - (sizeof(*outip) + optlen)));
+       resize_packet();
 }
 
 int