Author: melifaro
Date: Mon Nov 17 01:05:29 2014
New Revision: 274611
URL: https://svnweb.freebsd.org/changeset/base/274611
Log:
Finish r274175: do control plane MTU tracking.
Update route MTU in case of ifnet MTU change.
Add new RTF_FIXEDMTU to track explicitly specified MTU.
Old behavior:
ifconfig em0 mtu 1500->9000 -> all routes traversing em0 do not change MTU.
User has to manually update all routes.
ifconfig em0 mtu 9000->1500 -> all routes traversing em0 do not change MTU.
However, if ip[6]_output finds route with rt_mtu > interface mtu, rt_mtu
gets updated.
New behavior:
ifconfig em0 mtu 1500->9000 -> all interface routes in all fibs gets updated
with new MTU unless RTF_FIXEDMTU flag set on them.
ifconfig em0 mtu 9000->1500 -> all routes in all fibs gets updated with new
MTU unless RTF_FIXEDMTU flag set on them AND rt_mtu is less than ifp mtu.
route add ... -mtu XXX automatically sets RTF_FIXEDMTU flag.
route change .. -mtu 0 automatically removes RTF_FIXEDMTU flag.
PR: 194238
MFC after: 1 month
CR: D1125
Modified:
head/sbin/route/route.c
head/sys/net/if.c
head/sys/net/route.c
head/sys/net/route.h
head/sys/netinet/ip_output.c
head/sys/netinet6/ip6_output.c
Modified: head/sbin/route/route.c
==============================================================================
--- head/sbin/route/route.c Mon Nov 17 01:01:45 2014 (r274610)
+++ head/sbin/route/route.c Mon Nov 17 01:05:29 2014 (r274611)
@@ -1587,7 +1587,7 @@ static const char routeflags[] =
"\1UP\2GATEWAY\3HOST\4REJECT\5DYNAMIC\6MODIFIED\7DONE"
"\012XRESOLVE\013LLINFO\014STATIC\015BLACKHOLE"
"\017PROTO2\020PROTO1\021PRCLONING\022WASCLONED\023PROTO3"
- "\025PINNED\026LOCAL\027BROADCAST\030MULTICAST\035STICKY";
+ "\024FIXEDMTU\025PINNED\026LOCAL\027BROADCAST\030MULTICAST\035STICKY";
static const char ifnetflags[] =
"\1UP\2BROADCAST\3DEBUG\4LOOPBACK\5PTP\6b6\7RUNNING\010NOARP"
"\011PPROMISC\012ALLMULTI\013OACTIVE\014SIMPLEX\015LINK0\016LINK1"
Modified: head/sys/net/if.c
==============================================================================
--- head/sys/net/if.c Mon Nov 17 01:01:45 2014 (r274610)
+++ head/sys/net/if.c Mon Nov 17 01:05:29 2014 (r274611)
@@ -2494,6 +2494,7 @@ ifhwioctl(u_long cmd, struct ifnet *ifp,
#ifdef INET6
nd6_setmtu(ifp);
#endif
+ rt_updatemtu(ifp);
}
break;
}
Modified: head/sys/net/route.c
==============================================================================
--- head/sys/net/route.c Mon Nov 17 01:01:45 2014 (r274610)
+++ head/sys/net/route.c Mon Nov 17 01:05:29 2014 (r274611)
@@ -141,6 +141,14 @@ static int rtrequest1_fib_change(struct
struct rtentry **, u_int);
static void rt_setmetrics(const struct rt_addrinfo *, struct rtentry *);
+struct if_mtuinfo
+{
+ struct ifnet *ifp;
+ int mtu;
+};
+
+static int if_updatemtu_cb(struct radix_node *, void *);
+
/*
* handler for net.my_fibnum
*/
@@ -947,6 +955,70 @@ bad:
return (error);
}
+static int
+if_updatemtu_cb(struct radix_node *rn, void *arg)
+{
+ struct rtentry *rt;
+ struct if_mtuinfo *ifmtu;
+
+ rt = (struct rtentry *)rn;
+ ifmtu = (struct if_mtuinfo *)arg;
+
+ if (rt->rt_ifp != ifmtu->ifp)
+ return (0);
+
+ if (rt->rt_mtu >= ifmtu->mtu) {
+ /* We have to decrease mtu regardless of flags */
+ rt->rt_mtu = ifmtu->mtu;
+ return (0);
+ }
+
+ /*
+ * New MTU is bigger. Check if are allowed to alter it
+ */
+ if ((rt->rt_flags & (RTF_FIXEDMTU | RTF_GATEWAY | RTF_HOST)) != 0) {
+
+ /*
+ * Skip routes with user-supplied MTU and
+ * non-interface routes
+ */
+ return (0);
+ }
+
+ /* We are safe to update route MTU */
+ rt->rt_mtu = ifmtu->mtu;
+
+ return (0);
+}
+
+void
+rt_updatemtu(struct ifnet *ifp)
+{
+ struct if_mtuinfo ifmtu;
+ struct radix_node_head *rnh;
+ int i, j;
+
+ ifmtu.ifp = ifp;
+
+ /*
+ * Try to update rt_mtu for all routes using this interface
+ * Unfortunately the only way to do this is to traverse all
+ * routing tables in all fibs/domains.
+ */
+ for (i = 1; i <= AF_MAX; i++) {
+ ifmtu.mtu = if_getmtu_family(ifp, i);
+ for (j = 0; j < rt_numfibs; j++) {
+ rnh = rt_tables_get_rnh(j, i);
+ if (rnh == NULL)
+ continue;
+ RADIX_NODE_HEAD_LOCK(rnh);
+ rnh->rnh_walktree(rnh, if_updatemtu_cb, &ifmtu);
+ RADIX_NODE_HEAD_UNLOCK(rnh);
+ }
+ }
+}
+
+
#if 0
int p_sockaddr(char *buf, int buflen, struct sockaddr *s);
int rt_print(char *buf, int buflen, struct rtentry *rt);
@@ -1408,6 +1480,7 @@ rtrequest1_fib_change(struct radix_node_
int error = 0;
int free_ifa = 0;
int family, mtu;
+ struct if_mtuinfo ifmtu;
rt = (struct rtentry *)rnh->rnh_lookup(info->rti_info[RTAX_DST],
info->rti_info[RTAX_NETMASK], rnh);
@@ -1478,12 +1551,19 @@ rtrequest1_fib_change(struct radix_node_
if (rt->rt_ifa && rt->rt_ifa->ifa_rtrequest != NULL)
rt->rt_ifa->ifa_rtrequest(RTM_ADD, rt, info);
- /* Ensure route MTU is not bigger than interface MTU */
+ /* Alter route MTU if necessary */
if (rt->rt_ifp != NULL) {
family = info->rti_info[RTAX_DST]->sa_family;
mtu = if_getmtu_family(rt->rt_ifp, family);
- if (rt->rt_mtu > mtu)
+ /* Set default MTU */
+ if (rt->rt_mtu == 0)
rt->rt_mtu = mtu;
+ if (rt->rt_mtu != mtu) {
+ /* Check if we really need to update */
+ ifmtu.ifp = rt->rt_ifp;
+ ifmtu.mtu = mtu;
+ if_updatemtu_cb(rt->rt_nodes, &ifmtu);
+ }
}
if (ret_nrt) {
@@ -1501,8 +1581,24 @@ static void
rt_setmetrics(const struct rt_addrinfo *info, struct rtentry *rt)
{
- if (info->rti_mflags & RTV_MTU)
+ if (info->rti_mflags & RTV_MTU) {
+ if (info->rti_rmx->rmx_mtu != 0) {
+
+ /*
+ * MTU was explicitly provided by user.
+ * Keep it.
+ */
+ rt->rt_flags |= RTF_FIXEDMTU;
+ } else {
+
+ /*
+ * User explicitly sets MTU to 0.
+ * Assume rollback to default.
+ */
+ rt->rt_flags &= ~RTF_FIXEDMTU;
+ }
rt->rt_mtu = info->rti_rmx->rmx_mtu;
+ }
if (info->rti_mflags & RTV_WEIGHT)
rt->rt_weight = info->rti_rmx->rmx_weight;
/* Kernel -> userland timebase conversion. */
Modified: head/sys/net/route.h
==============================================================================
--- head/sys/net/route.h Mon Nov 17 01:01:45 2014 (r274610)
+++ head/sys/net/route.h Mon Nov 17 01:05:29 2014 (r274611)
@@ -151,7 +151,7 @@ struct rtentry {
/* 0x10000 unused, was RTF_PRCLONING */
/* 0x20000 unused, was RTF_WASCLONED */
#define RTF_PROTO3 0x40000 /* protocol specific routing flag */
-/* 0x80000 unused */
+#define RTF_FIXEDMTU 0x80000 /* MTU was explicitly specified
*/
#define RTF_PINNED 0x100000 /* route is immutable */
#define RTF_LOCAL 0x200000 /* route represents a local
address */
#define RTF_BROADCAST 0x400000 /* route represents a bcast
address */
@@ -378,6 +378,7 @@ int rtsock_routemsg(int, struct ifnet *i
int rt_expunge(struct radix_node_head *, struct rtentry *);
void rtfree(struct rtentry *);
int rt_check(struct rtentry **, struct rtentry **, struct sockaddr *);
+void rt_updatemtu(struct ifnet *);
/* XXX MRT COMPAT VERSIONS THAT SET UNIVERSE to 0 */
/* Thes are used by old code not yet converted to use multiple FIBS */
Modified: head/sys/netinet/ip_output.c
==============================================================================
--- head/sys/netinet/ip_output.c Mon Nov 17 01:01:45 2014
(r274610)
+++ head/sys/netinet/ip_output.c Mon Nov 17 01:05:29 2014
(r274611)
@@ -322,20 +322,10 @@ again:
* Calculate MTU. If we have a route that is up, use that,
* otherwise use the interface's MTU.
*/
- if (rte != NULL && (rte->rt_flags & (RTF_UP|RTF_HOST))) {
- /*
- * This case can happen if the user changed the MTU
- * of an interface after enabling IP on it. Because
- * most netifs don't keep track of routes pointing to
- * them, there is no way for one to update all its
- * routes when the MTU is changed.
- */
- if (rte->rt_mtu > ifp->if_mtu)
- rte->rt_mtu = ifp->if_mtu;
+ if (rte != NULL && (rte->rt_flags & (RTF_UP|RTF_HOST)))
mtu = rte->rt_mtu;
- } else {
+ else
mtu = ifp->if_mtu;
- }
/* Catch a possible divide by zero later. */
KASSERT(mtu > 0, ("%s: mtu %d <= 0, rte=%p (rt_flags=0x%08x) ifp=%p",
__func__, mtu, rte, (rte != NULL) ? rte->rt_flags : 0, ifp));
Modified: head/sys/netinet6/ip6_output.c
==============================================================================
--- head/sys/netinet6/ip6_output.c Mon Nov 17 01:01:45 2014
(r274610)
+++ head/sys/netinet6/ip6_output.c Mon Nov 17 01:05:29 2014
(r274611)
@@ -1275,17 +1275,6 @@ ip6_getpmtu(struct route_in6 *ro_pmtu, s
*/
alwaysfrag = 1;
mtu = IPV6_MMTU;
- } else if (mtu > ifmtu) {
- /*
- * The MTU on the route is larger than the MTU on
- * the interface! This shouldn't happen, unless the
- * MTU of the interface has been changed after the
- * interface was brought up. Change the MTU in the
- * route to match the interface MTU (as long as the
- * field isn't locked).
- */
- mtu = ifmtu;
- ro_pmtu->ro_rt->rt_mtu = mtu;
}
} else if (ifp) {
mtu = IN6_LINKMTU(ifp);
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