if-bsd: support ROUTE_MSGFILTER socket option

This reduces needless context switching just to discard route(4)
message types we're not interested in.

diff --git a/src/if-bsd.c b/src/if-bsd.c
index 504811dbb24c1dd5cfbf4f486ee61b1be2e72b58..eeb5a4b433dc210465f5b60aee3962d0689bbabf 100644 (file)
--- a/src/if-bsd.c
+++ b/src/if-bsd.c
@@ -120,6 +120,9 @@ int
 if_opensockets_os(struct dhcpcd_ctx *ctx)
 {
        struct priv *priv;
+#ifdef ROUTE_MSGFILTER
+       unsigned int msgfilter;
+#endif
 
        if ((priv = malloc(sizeof(*priv))) == NULL)
                return -1;
@@ -137,6 +140,25 @@ if_opensockets_os(struct dhcpcd_ctx *ctx)
 #define SOCK_FLAGS     (SOCK_CLOEXEC | SOCK_NONBLOCK)
        ctx->link_fd = xsocket(PF_ROUTE, SOCK_RAW | SOCK_FLAGS, AF_UNSPEC);
 #undef SOCK_FLAGS
+
+#ifdef ROUTE_MSGFILTER
+       msgfilter = ROUTE_FILTER(RTM_IFINFO)
+#ifdef RTM_IFANNOUNCE
+           | ROUTE_FILTER(RTM_IFANNOUNCE)
+#endif
+           | ROUTE_FILTER(RTM_ADD)
+           | ROUTE_FILTER(RTM_CHANGE)
+           | ROUTE_FILTER(RTM_DELETE)
+#ifdef RTM_CHGADDR
+           | ROUTE_FILTER(RTM_CHGADDR)
+#endif
+           | ROUTE_FILTER(RTM_DELADDR)
+           | ROUTE_FILTER(RTM_NEWADDR);
+       if (setsockopt(ctx->link_fd, PF_ROUTE, ROUTE_MSGFILTER,
+           &msgfilter, sizeof(msgfilter)) == -1)
+               syslog(LOG_ERR, "ROUTE_MSGFILTER: %m");
+#endif
+
        return ctx->link_fd == -1 ? -1 : 0;
 }