link: detect buffer overflow / desync and relearn interface state

It's possible for the internal kernel buffer that reports network
events to overflow.
On Linux and NetBSD* this is handled by ENOBUFS being returned
by recv(2). On OpenBSD there is a special route(4) message RTM_DESYNC.
All other OS's don't seem to report this error, so dhcpcd cannot
detect it.

* I will commit a patch to NetBSD soon for this and will request a
pullup to NetBSD-8.

1 files changed, 30 insertions, 0 deletions

diff --git a/src/if.c b/src/if.c
index e3641ac6..208da245 100644
--- a/src/if.c
+++ b/src/if.c
@@ -191,6 +191,21 @@ if_hasconf(struct dhcpcd_ctx *ctx, const char *ifname)
 }
 
 void
+if_markaddrsstale(struct if_head *ifs)
+{
+	struct interface *ifp;
+
+	TAILQ_FOREACH(ifp, ifs, next) {
+#ifdef INET
+		ipv4_markaddrsstale(ifp);
+#endif
+#ifdef INET6
+		ipv6_markaddrsstale(ifp, 0);
+#endif
+	}
+}
+
+void
 if_learnaddrs(struct dhcpcd_ctx *ctx, struct if_head *ifs,
     struct ifaddrs **ifaddrs)
 {
@@ -268,6 +283,21 @@ if_learnaddrs(struct dhcpcd_ctx *ctx, struct if_head *ifs,
 	*ifaddrs = NULL;
 }
 
+void
+if_deletestaleaddrs(struct if_head *ifs)
+{
+	struct interface *ifp;
+
+	TAILQ_FOREACH(ifp, ifs, next) {
+#ifdef INET
+		ipv4_deletestaleaddrs(ifp);
+#endif
+#ifdef INET6
+		ipv6_deletestaleaddrs(ifp);
+#endif
+	}
+}
+
 bool
 if_valid_hwaddr(const uint8_t *hwaddr, size_t hwlen)
 {