From 2596e591085f0586a74ed6f55f298bc0f66fb9ee Mon Sep 17 00:00:00 2001
From: Ian Lepore <ian@FreeBSD.org>
Date: Sun, 27 Mar 2016 23:16:37 +0000
Subject: [PATCH] Do not try to install a default route for each interface
 found, because only the first one will actually work and all the others just
 result in errors (which would get printed but otherwise ignored).

Instead, wait until we make a choice of which interface will be used to
mount the rootfs, and install the default route associated with it (if any).
After doing the md_mount() call to obtain the needed info, remove the
default route again, and transcribe the route info into the nfs_diskless
structure.  If the system eventually chooses to mount the nfs rootfs, the
default route will be installed again when the nfs_diskless code
re-initializes the interface.

The theory here is that since we can only have one default route, the one
most likely to be correct for mounting the rootfs is the one that was
delivered along with the rootpath option.
---
 sys/nfs/bootp_subr.c | 59 +++++++++++++++++++++++++++++++-------------
 1 file changed, 42 insertions(+), 17 deletions(-)

diff --git a/sys/nfs/bootp_subr.c b/sys/nfs/bootp_subr.c
index 044ba0ff0c2d..51c76e767755 100644
--- a/sys/nfs/bootp_subr.c
+++ b/sys/nfs/bootp_subr.c
@@ -1016,20 +1016,16 @@ bootpc_adjust_interface(struct bootpc_ifcontext *ifctx,
     struct bootpc_globalcontext *gctx, struct thread *td)
 {
 	int error;
-	struct sockaddr_in defdst;
-	struct sockaddr_in defmask;
 	struct sockaddr_in *sin;
 	struct ifreq *ifr;
 	struct in_aliasreq *ifra;
 	struct sockaddr_in *myaddr;
 	struct sockaddr_in *netmask;
-	struct sockaddr_in *gw;
 
 	ifr = &ifctx->ireq;
 	ifra = &ifctx->iareq;
 	myaddr = &ifctx->myaddr;
 	netmask = &ifctx->netmask;
-	gw = &ifctx->gw;
 
 	if (bootpc_ifctx_isresolved(ifctx) == 0) {
 		/* Shutdown interfaces where BOOTP failed */
@@ -1069,21 +1065,47 @@ bootpc_adjust_interface(struct bootpc_ifcontext *ifctx,
 	error = ifioctl(bootp_so, SIOCAIFADDR, (caddr_t)ifra, td);
 	if (error != 0)
 		panic("%s: SIOCAIFADDR, error=%d", __func__, error);
+}
 
-	/* Add new default route */
+static void
+bootpc_add_default_route(struct bootpc_ifcontext *ifctx)
+{
+	int error;
+	struct sockaddr_in defdst;
+	struct sockaddr_in defmask;
 
-	if (ifctx->gw.sin_addr.s_addr != htonl(INADDR_ANY))
-		clear_sinaddr(&defdst);
-		clear_sinaddr(&defmask);
-		/* XXX MRT just table 0 */
-		error = rtrequest_fib(RTM_ADD,
-		    (struct sockaddr *) &defdst, (struct sockaddr *) gw,
-		    (struct sockaddr *) &defmask,
-		    (RTF_UP | RTF_GATEWAY | RTF_STATIC), NULL, RT_DEFAULT_FIB);
-		if (error != 0) {
-			printf("%s: RTM_ADD, error=%d\n", __func__, error);
-			return;
-		}
+	if (ifctx->gw.sin_addr.s_addr == htonl(INADDR_ANY))
+		return;
+
+	clear_sinaddr(&defdst);
+	clear_sinaddr(&defmask);
+
+	error = rtrequest_fib(RTM_ADD, (struct sockaddr *)&defdst,
+	    (struct sockaddr *) &ifctx->gw, (struct sockaddr *)&defmask,
+	    (RTF_UP | RTF_GATEWAY | RTF_STATIC), NULL, RT_DEFAULT_FIB);
+	if (error != 0) {
+		printf("%s: RTM_ADD, error=%d\n", __func__, error);
+	}
+}
+
+static void
+bootpc_remove_default_route(struct bootpc_ifcontext *ifctx)
+{
+	int error;
+	struct sockaddr_in defdst;
+	struct sockaddr_in defmask;
+
+	if (ifctx->gw.sin_addr.s_addr == htonl(INADDR_ANY))
+		return;
+
+	clear_sinaddr(&defdst);
+	clear_sinaddr(&defmask);
+
+	error = rtrequest_fib(RTM_DELETE, (struct sockaddr *)&defdst,
+	    (struct sockaddr *) &ifctx->gw, (struct sockaddr *)&defmask,
+	    (RTF_UP | RTF_GATEWAY | RTF_STATIC), NULL, RT_DEFAULT_FIB);
+	if (error != 0) {
+		printf("%s: RTM_DELETE, error=%d\n", __func__, error);
 	}
 }
 
@@ -1743,9 +1765,11 @@ bootpc_init(void)
 
 		kern_setenv("boot.netif.name", ifctx->ifp->if_xname);
 
+		bootpc_add_default_route(ifctx);
 		error = md_mount(&nd->root_saddr, nd->root_hostnam,
 				 nd->root_fh, &nd->root_fhsize,
 				 &nd->root_args, td);
+		bootpc_remove_default_route(ifctx);
 		if (error != 0) {
 			if (gctx->any_root_overrides == 0)
 				panic("nfs_boot: mount root, error=%d", error);
@@ -1763,6 +1787,7 @@ bootpc_init(void)
 		ifctx->myaddr.sin_addr.s_addr |
 		~ ifctx->netmask.sin_addr.s_addr;
 	bcopy(&ifctx->netmask, &nd->myif.ifra_mask, sizeof(ifctx->netmask));
+	bcopy(&ifctx->gw, &nd->mygateway, sizeof(ifctx->gw));
 
 out:
 	while((ifctx = STAILQ_FIRST(&gctx->interfaces)) != NULL) {