From: Guy Harris <guy@alum.mit.edu>
Date: Tue, 1 May 2018 07:32:32 +0000 (-0700)
Subject: Don't mark loopback devices as "connection status unknown".
X-Git-Tag: libpcap-1.9-bp~58
X-Git-Url: https://git.tcpdump.org/libpcap/commitdiff_plain/ff647f1d116edaff3006ea0f99dd07b9b74622e6?ds=sidebyside

Don't mark loopback devices as "connection status unknown".

It's not unknown, it's *inapplicable*.
---

diff --git a/pcap-bpf.c b/pcap-bpf.c
index e06f8073..9f4c62b5 100644
--- a/pcap-bpf.c
+++ b/pcap-bpf.c
@@ -2804,8 +2804,22 @@ static int
 get_if_flags(const char *name _U_, bpf_u_int32 *flags _U_, char *errbuf _U_)
 {
 	/*
-	 * Nothing we can do.
+	 * Nothing we can do other than mark loopback devices as "the
+	 * connected/disconnected status doesn't apply".
+	 *
+	 * XXX - on Solaris, can we do what the dladm command does,
+	 * i.e. get a connected/disconnected indication from a kstat?
+	 * (Note that you can also get the link speed, and possibly
+	 * other information, from a kstat as well.)
 	 */
+	if (*flags & PCAP_IF_LOOPBACK) {
+		/*
+		 * Loopback devices aren't wireless, and "connected"/
+		 * "disconnected" doesn't apply to them.
+		 */
+		*flags |= PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
+		return (0);
+	}
 	return (0);
 }
 #endif