Hi,
The following diff adds the option -e to ndp(8), which resolved printed
hostnames via /etc/ethers. You are able to recognise hosts with IPv6
auto privacy extension addresses on local IPv6 routers. Also hosts
inside of a yp(8) domain are able to lookup their neighbors via the
shared /etc/ethers database. (Yes, I run a yp domain :-)
This helps me, to keep track of known and unknown IPv6 hosts in my
network.
The ndp(8) implementations of FreeBSD, NetBSD and Linux don't have an
option named -e or a feature like this. Thus, there shouldn't be any
problem or misbehavior by existing scripts around ndp(8) with this new
option.
What's your opinion about this feature?
Bye,
Jan
Index: ndp.8
===================================================================
RCS file: /cvs/src/usr.sbin/ndp/ndp.8,v
retrieving revision 1.45
diff -u -p -r1.45 ndp.8
--- ndp.8 9 Aug 2017 14:36:00 -0000 1.45
+++ ndp.8 22 Oct 2018 21:32:46 -0000
@@ -36,7 +36,7 @@
.Nd control/diagnose IPv6 Neighbor Discovery Protocol (NDP)
.Sh SYNOPSIS
.Nm ndp
-.Op Fl acnt
+.Op Fl acent
.Op Fl A Ar wait
.Op Fl d Ar hostname
.Op Fl f Ar filename
@@ -112,6 +112,12 @@ the node has sent during the current sta
Erase all the NDP entries.
.It Fl d Ar hostname
Delete the specified NDP entry.
+.It Fl e
+Use the mappings of ethernet addresses in
+.Pa /etc/ethers
+to resolve hostnames.
+This is useful to resolve hostnames of privacy externsion addresses on local
+routers.
.It Fl f Ar filename
Parse entries from
.Ar file
Index: ndp.c
===================================================================
RCS file: /cvs/src/usr.sbin/ndp/ndp.c,v
retrieving revision 1.90
diff -u -p -r1.90 ndp.c
--- ndp.c 13 Jul 2018 09:03:44 -0000 1.90
+++ ndp.c 22 Oct 2018 21:38:54 -0000
@@ -86,6 +86,7 @@
#include <net/route.h>
#include <netinet/in.h>
+#include <netinet/if_ether.h>
#include <netinet/icmp6.h>
#include <netinet6/in6_var.h>
@@ -110,6 +111,7 @@
((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
static pid_t pid;
+static int eflag;
static int nflag;
static int tflag;
static int32_t thiszone; /* time difference with gmt */
@@ -148,7 +150,7 @@ main(int argc, char *argv[])
pid = getpid();
thiszone = gmt2local(0);
rdomain = getrtable();
- while ((ch = getopt(argc, argv, "acd:f:i:nstA:V:")) != -1) {
+ while ((ch = getopt(argc, argv, "acd:ef:i:nstA:V:")) != -1) {
switch (ch) {
case 'a':
case 'c':
@@ -173,6 +175,9 @@ main(int argc, char *argv[])
mode = ch;
arg = optarg;
break;
+ case 'e':
+ eflag = 1;
+ break;
case 'n':
nflag = 1;
break;
@@ -612,6 +617,17 @@ again:;
delete(host_buf);
continue;
}
+
+ if (eflag && sdl->sdl_alen) {
+ u_char *cp = (u_char *)LLADDR(sdl);
+ struct ether_addr eaddr;
+ char nhost[NI_MAXHOST];
+
+ memcpy(eaddr.ether_addr_octet, cp, ETHER_ADDR_LEN);
+ if (ether_ntohost(nhost, &eaddr) == 0)
+ strlcpy(host_buf, nhost, sizeof(host_buf));
+ }
+
gettimeofday(&now, 0);
if (tflag)
ts_print(&now);
@@ -753,7 +769,7 @@ ndp_ether_aton(char *a, u_char *n)
void
usage(void)
{
- printf("usage: ndp [-acnt] ");
+ printf("usage: ndp [-acent] ");
printf("[-A wait] [-d hostname] [-f filename] [-i interface]\n");
printf("\t[-s nodename ether_addr [temp] [proxy]] ");
printf("[-V rdomain] [hostname]\n");
