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Use a little bit of magic suggested by Ken Hornstein to find an 

appropriate source address for the UDP packets. Fixes PR bin/4427
by Luke Mewburn.
This commit is contained in:
tron 1998-12-09 22:53:29 +00:00
parent 98394c66d1
commit 8c2d809b71
1 changed files with 38 additions and 4 deletions
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42
usr.sbin/traceroute/traceroute.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: traceroute.c,v 1.25 1998/08/27 20:31:02 ross Exp $ */
/* $NetBSD: traceroute.c,v 1.26 1998/12/09 22:53:29 tron Exp $ */
/*
* Copyright (c) 1988, 1989, 1991, 1994, 1995, 1996, 1997
@ -29,7 +29,7 @@ static const char rcsid[] =
#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 1.25 1998/08/27 20:31:02 ross Exp $");
__RCSID("$NetBSD: traceroute.c,v 1.26 1998/12/09 22:53:29 tron Exp $");
#endif
#endif
@ -359,7 +359,7 @@ void tvsub(struct timeval *, struct timeval *);
__dead void usage(void);
int wait_for_reply(int, struct sockaddr_in *, struct timeval *);
void frag_err(void);
int find_local_ip(struct sockaddr_in *, struct sockaddr_in *);
int
main(int argc, char **argv)
@ -729,7 +729,7 @@ main(int argc, char **argv)
* Warn if there are more than one.
*/
setsin(from, al->addr);
if (n > 1 && device == NULL) {
if (n > 1 && device == NULL && !find_local_ip(from, to)) {
Fprintf(stderr,
"%s: Warning: Multiple interfaces found; using %s @ %s\n",
prog, inet_ntoa(from->sin_addr), al->device);
@ -1466,3 +1466,37 @@ frag_err()
}
}
int
find_local_ip(struct sockaddr_in *from, struct sockaddr_in *to)
{
int sock;
struct sockaddr_in help;
int help_len;
sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock < 0) return (0);
help.sin_family = AF_INET;
/*
* At this point the port number doesn't matter
* since it only has to be greater than zero.
*/
help.sin_port = 42;
help.sin_addr.s_addr = to->sin_addr.s_addr;
if (connect(sock, (struct sockaddr *)&help, sizeof(help)) < 0) {
(void)close(sock);
return (0);
}
help_len = sizeof(help);
if (getsockname(sock, (struct sockaddr *)&help, &help_len) < 0 ||
help_len != sizeof(help) ||
help.sin_addr.s_addr == INADDR_ANY) {
(void)close(sock);
return (0);
}
(void)close(sock);
setsin(from, help.sin_addr.s_addr);
return (1);
}