From 66fb5a777b3ca7e13763964a4772314711c0ea2f Mon Sep 17 00:00:00 2001
From: Roy Marples <roy@marples.name>
Date: Fri, 7 Feb 2025 11:47:01 +0000
Subject: [PATCH] BSD: Improve NEWADDR == IFF_UP handling

On BSD when an address is added, the interface is automatically
brought up.
We can detect this by RTM_NEWADDR, but that lacks the IFF_UP flag.
We really want to stay in sync with RTM messages for flags, but
here we need to check the interface for IFF_UP if we think it's
not there. Only set that.

This fixes NEWADDR announcements for state transitions when
the interface is currently down.
---
 src/if-bsd.c | 14 ++++++++++++--
 src/if-sun.c |  5 +----
 src/if.c     | 12 ------------
 src/if.h     |  1 -
 4 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/src/if-bsd.c b/src/if-bsd.c
index 5b4c43a0..d184ef84 100644
--- a/src/if-bsd.c
+++ b/src/if-bsd.c
@@ -1352,8 +1352,18 @@ if_ifa(struct dhcpcd_ctx *ctx, const struct ifa_msghdr *ifam)
 
 	/* All BSD's set IFF_UP on the interface when adding an address.
 	 * But not all BSD's emit this via RTM_IFINFO when they do this ... */
-	if (ifam->ifam_type == RTM_NEWADDR && !(ifp->flags & IFF_UP))
-		dhcpcd_handlecarrier(ifp, ifp->carrier, ifp->flags | IFF_UP);
+	if (ifam->ifam_type == RTM_NEWADDR && !(ifp->flags & IFF_UP)) {
+		struct ifreq ifr = { .ifr_flags = 0 };
+
+		/* Don't blindly assume the interface is up though.
+		 * We might get the address via a state change. */
+		strlcpy(ifr.ifr_name, ifp->name, sizeof(ifr.ifr_name));
+		if (ioctl(ctx->pf_inet_fd, SIOCGIFFLAGS, &ifr) == -1)
+			return -1;
+		if (ifr.ifr_flags & IFF_UP)
+			dhcpcd_handlecarrier(ifp, ifp->carrier,
+			    ifp->flags | IFF_UP);
+	}
 
 	switch (rti_info[RTAX_IFA]->sa_family) {
 	case AF_LINK:
diff --git a/src/if-sun.c b/src/if-sun.c
index c1350cb6..8b774c29 100644
--- a/src/if-sun.c
+++ b/src/if-sun.c
@@ -205,9 +205,6 @@ if_carrier(struct interface *ifp, __unused const void *ifadata)
 	kstat_named_t		*knp;
 	link_state_t		linkstate;
 
-	if (if_getflags(ifp) == -1)
-		return LINK_UNKNOWN;
-
 	kcp = kstat_open();
 	if (kcp == NULL)
 		goto err;
@@ -226,7 +223,7 @@ if_carrier(struct interface *ifp, __unused const void *ifadata)
 
 	switch (linkstate) {
 	case LINK_STATE_UP:
-		ifp->flags |= IFF_UP;
+		ifp->flags |= IFF_UP; /* XXX Why? */
 		return LINK_UP;
 	case LINK_STATE_DOWN:
 		return LINK_DOWN;
diff --git a/src/if.c b/src/if.c
index 17bf37a5..dea833df 100644
--- a/src/if.c
+++ b/src/if.c
@@ -157,18 +157,6 @@ if_ioctl(struct dhcpcd_ctx *ctx, ioctl_request_t req, void *data, size_t len)
 	return ioctl(ctx->pf_inet_fd, req, data, len);
 }
 
-int
-if_getflags(struct interface *ifp)
-{
-	struct ifreq ifr = { .ifr_flags = 0 };
-
-	strlcpy(ifr.ifr_name, ifp->name, sizeof(ifr.ifr_name));
-	if (ioctl(ifp->ctx->pf_inet_fd, SIOCGIFFLAGS, &ifr) == -1)
-		return -1;
-	ifp->flags = (unsigned int)ifr.ifr_flags;
-	return 0;
-}
-
 int
 if_setflag(struct interface *ifp, short setflag, short unsetflag)
 {
diff --git a/src/if.h b/src/if.h
index 3a37576c..6cb9d766 100644
--- a/src/if.h
+++ b/src/if.h
@@ -162,7 +162,6 @@ int if_ioctl(struct dhcpcd_ctx *, ioctl_request_t, void *, size_t);
 #else
 #define	pioctl(ctx, req, data, len) ioctl((ctx)->pf_inet_fd, (req),(data),(len))
 #endif
-int if_getflags(struct interface *);
 int if_setflag(struct interface *, short, short);
 #define if_up(ifp) if_setflag((ifp), (IFF_UP | IFF_RUNNING), 0)
 #define if_down(ifp) if_setflag((ifp), 0, IFF_UP);
-- 
2.47.3