Re: if_addrflags6: Can't assign requested address

[Roy Marples <roy%marples.name@localhost>]

On 17/08/2018 09:04, Masanobu SAITOH wrote:
> > wm2: carrier lost
> > wm2: executing `/libexec/dhcpcd-run-hooks' NOCARRIER
> > wm2: deleting address fe80::1392:4012:56d8:a7a2
> > wm2: if_addrflags6: Can't assign requested address
> > wm2: if_addrflags6: Can't assign requested address
> > wm2: if_addrflags6: Can't assign requested address
> > wm2: if_addrflags6: Can't assign requested address
> > wm2: carrier acquired
> > wm2: executing `/libexec/dhcpcd-run-hooks' CARRIER

This helps.
I never saw this because on NetBSD-8, we have addrflags available in 
ifa_msghdr when sent over route(4). This does not exist on NetBSD-7 so 
we need to make an ioctl per address to work out the flags. Sadly, this 
is racy and this is what happens:

Something adds an address.
Kernel annnounces new address to route(4).
Something deletes this address.
Kernel announces the address deleted to route(4).

dhcpcd reads the address added message from route(4) *after* the address 
has been deleted from the kernel. Because dhcpcd needs the address flags 
at this point, an ioctl is made to the deleted address and boom, error.

Luckily dhcpcd handles it correctly and it's just noise.
Please test the attached patch to silence it.
If you can verify it works, let me know and I'll push a new version out.

Thanks

Roy

diff --git a/src/if-bsd.c b/src/if-bsd.c
index c3c95ba6..c03e4f6d 100644
--- a/src/if-bsd.c
+++ b/src/if-bsd.c
@@ -1134,8 +1134,8 @@ if_ifa(struct dhcpcd_ctx *ctx, const struct ifa_msghdr *ifam)
 		if (ifam->ifam_type == RTM_DELADDR)
 			addrflags = 0 ;
 		else if ((addrflags = if_addrflags(ifp, &addr, NULL)) == -1) {
-			logerr("%s: if_addrflags: %s",
-			    ifp->name, inet_ntoa(addr));
+			if (errno != EADDRNOTAVAIL)
+				logerr("%s: if_addrflags", __func__);
 			break;
 		}
 #endif
@@ -1160,7 +1160,8 @@ if_ifa(struct dhcpcd_ctx *ctx, const struct ifa_msghdr *ifam)
 		if (ifam->ifam_type == RTM_DELADDR)
 		    addrflags = 0;
 		else if ((addrflags = if_addrflags6(ifp, &addr6, NULL)) == -1) {
-			logerr("%s: if_addrflags6", ifp->name);
+			if (errno != EADDRNOTAVAIL)
+				logerr("%s: if_addrflags6", __func__);
 			break;
 		}
 #endif
diff --git a/src/if.c b/src/if.c
index eaebefa5..c1c81eb6 100644
--- a/src/if.c
+++ b/src/if.c
@@ -240,7 +240,7 @@ if_learnaddrs(struct dhcpcd_ctx *ctx, struct if_head *ifs,
 			addrflags = if_addrflags(ifp, &addr->sin_addr,
 			    ifa->ifa_name);
 			if (addrflags == -1) {
-				if (errno != EEXIST)
+				if (errno != EEXIST && errno != EADDRNOTAVAIL)
 					logerr("%s: if_addrflags: %s",
 					    __func__,
 					    inet_ntoa(addr->sin_addr));
@@ -266,7 +266,7 @@ if_learnaddrs(struct dhcpcd_ctx *ctx, struct if_head *ifs,
 			addrflags = if_addrflags6(ifp, &sin6->sin6_addr,
 			    ifa->ifa_name);
 			if (addrflags == -1) {
-				if (errno != EEXIST)
+				if (errno != EEXIST || errno == EADDRNOTAVAIL)
 					logerr("%s: if_addrflags6", __func__);
 				continue;
 			}