git: 1e74fc950419 - stable/14 - arp: fix arp -s/-S

The branch stable/14 has been updated by glebius:

URL: https://cgit.FreeBSD.org/src/commit/?id=1e74fc950419f2b2482d313fc664cc03aa46f13c

commit 1e74fc950419f2b2482d313fc664cc03aa46f13c
Author:     Gleb Smirnoff <glebius@FreeBSD.org>
AuthorDate: 2024-02-20 18:31:05 +0000
Commit:     Gleb Smirnoff <glebius@FreeBSD.org>
CommitDate: 2024-02-25 18:03:17 +0000

    arp: fix arp -s/-S
    
    When setting a permanent ARP entry, the route(4) would use
    rtm->rtm_rmx.rmx_expire == 0 as a flag for installing a static entry, but
    netlink(4) is looking for explicit NTF_STICKY flag in the request.  The
    arp(8) utility was adopted to use netlink(4) by default, but it has lots
    of route-era guts internally. Specifically there is global variable 'opts'
    that shares configuration for both protocols, and it is still initialized
    with route(4) specific RTF_xxx flags.  In set_nl() these flags are
    translated to netlink(4) parameters. However, RTF_STATIC is a flag that is
    never set by default, so attempt to use it as a proxy flag manifesting
    -s/-S results in losing it.  Use zero opts.expire_time as a manifest of
    -s/-S operation.  This is a minimal fix.  A better one would be to fully
    get rid of route(4) legacy.
    
    The change also corrects the logic to set NUD_PERMANENT flag for
    consistency.  This flag is ignored by our kernel (now).
    
    Reviewed by:            melifaro, tuexen, emaste
    PR:                     277063
    Fixes:                  6ad73dbf65048b0950a1ba6ff25607f6708c8954
    Differential Revision:  https://reviews.freebsd.org/D43983
    
    (cherry picked from commit 6a3e87e1306d5058d63f7552a25ed6376422f658)
---
 usr.sbin/arp/arp_netlink.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/usr.sbin/arp/arp_netlink.c b/usr.sbin/arp/arp_netlink.c
index d78f380af04b..8644f3722aed 100644
--- a/usr.sbin/arp/arp_netlink.c
+++ b/usr.sbin/arp/arp_netlink.c
@@ -390,9 +390,6 @@ set_nl(uint32_t ifindex, struct sockaddr_in *dst, struct sockaddr_dl *sdl, char
 		return (0);
 	}
 
-	if (opts.expire_time != 0)
-		opts.flags &= ~RTF_STATIC;
-
 	snl_init_writer(&ss, &nw);
 	struct nlmsghdr *hdr = snl_create_msg_request(&nw, RTM_NEWNEIGH);
 	hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
@@ -402,11 +399,12 @@ set_nl(uint32_t ifindex, struct sockaddr_in *dst, struct sockaddr_dl *sdl, char
 
 		ndmsg->ndm_family = AF_INET;
 		ndmsg->ndm_ifindex = ifindex;
-		ndmsg->ndm_state = (opts.flags & RTF_STATIC) ? NUD_PERMANENT : NUD_NONE;
+		ndmsg->ndm_state = (opts.expire_time == 0) ? \
+		    NUD_PERMANENT : NUD_NONE;
 
 		if (opts.flags & RTF_ANNOUNCE)
 			nl_flags |= NTF_PROXY;
-		if (opts.flags & RTF_STATIC)
+		if (opts.expire_time == 0)
 			nl_flags |= NTF_STICKY;
 		ndmsg->ndm_flags = nl_flags;
 	}