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net: Propagate lookup failure in l3mdev_get_saddr to caller 

Commands run in a vrf context are not failing as expected on a route lookup:
    root@kenny:~# ip ro ls table vrf-red
    unreachable default

    root@kenny:~# ping -I vrf-red -c1 -w1 10.100.1.254
    ping: Warning: source address might be selected on device other than vrf-red.
    PING 10.100.1.254 (10.100.1.254) from 0.0.0.0 vrf-red: 56(84) bytes of data.

    --- 10.100.1.254 ping statistics ---
    2 packets transmitted, 0 received, 100% packet loss, time 999ms

Since the vrf table does not have a route for 10.100.1.254 the ping
should have failed. The saddr lookup causes a full VRF table lookup.
Propogating a lookup failure to the user allows the command to fail as
expected:

    root@kenny:~# ping -I vrf-red -c1 -w1 10.100.1.254
    connect: No route to host

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2016-01-04 09:09:27 -08:00 committed by David S. Miller
parent 7ec2541aa7
commit b5bdacf3bb
5 changed files with 33 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/net/vrf.c
View File

@ -800,7 +800,7 @@ static struct rtable *vrf_get_rtable(const struct net_device *dev,
}
/* called under rcu_read_lock */
static void vrf_get_saddr(struct net_device *dev, struct flowi4 *fl4)
static int vrf_get_saddr(struct net_device *dev, struct flowi4 *fl4)
{
struct fib_result res = { .tclassid = 0 };
struct net *net = dev_net(dev);
@ -808,9 +808,10 @@ static void vrf_get_saddr(struct net_device *dev, struct flowi4 *fl4)
u8 flags = fl4->flowi4_flags;
u8 scope = fl4->flowi4_scope;
u8 tos = RT_FL_TOS(fl4);
int rc;
if (unlikely(!fl4->daddr))
return;
return 0;
fl4->flowi4_flags |= FLOWI_FLAG_SKIP_NH_OIF;
fl4->flowi4_iif = LOOPBACK_IFINDEX;
@ -818,7 +819,8 @@ static void vrf_get_saddr(struct net_device *dev, struct flowi4 *fl4)
fl4->flowi4_scope = ((tos & RTO_ONLINK) ?
RT_SCOPE_LINK : RT_SCOPE_UNIVERSE);
if (!fib_lookup(net, fl4, &res, 0)) {
rc = fib_lookup(net, fl4, &res, 0);
if (!rc) {
if (res.type == RTN_LOCAL)
fl4->saddr = res.fi->fib_prefsrc ? : fl4->daddr;
else
@ -828,6 +830,8 @@ static void vrf_get_saddr(struct net_device *dev, struct flowi4 *fl4)
fl4->flowi4_flags = flags;
fl4->flowi4_tos = orig_tos;
fl4->flowi4_scope = scope;
return rc;
}
#if IS_ENABLED(CONFIG_IPV6)

16
include/net/l3mdev.h
View File

@ -29,7 +29,7 @@ struct l3mdev_ops {
/* IPv4 ops */
struct rtable * (*l3mdev_get_rtable)(const struct net_device *dev,
const struct flowi4 *fl4);
void (*l3mdev_get_saddr)(struct net_device *dev,
int (*l3mdev_get_saddr)(struct net_device *dev,
struct flowi4 *fl4);
/* IPv6 ops */
@ -112,10 +112,11 @@ static inline bool netif_index_is_l3_master(struct net *net, int ifindex)
return rc;
}
static inline void l3mdev_get_saddr(struct net *net, int ifindex,
struct flowi4 *fl4)
static inline int l3mdev_get_saddr(struct net *net, int ifindex,
struct flowi4 *fl4)
{
struct net_device *dev;
int rc = 0;
if (ifindex) {
@ -124,11 +125,13 @@ static inline void l3mdev_get_saddr(struct net *net, int ifindex,
dev = dev_get_by_index_rcu(net, ifindex);
if (dev && netif_is_l3_master(dev) &&
dev->l3mdev_ops->l3mdev_get_saddr) {
dev->l3mdev_ops->l3mdev_get_saddr(dev, fl4);
rc = dev->l3mdev_ops->l3mdev_get_saddr(dev, fl4);
}
rcu_read_unlock();
}
return rc;
}
static inline struct dst_entry *l3mdev_get_rt6_dst(const struct net_device *dev,
@ -200,9 +203,10 @@ static inline bool netif_index_is_l3_master(struct net *net, int ifindex)
return false;
}
static inline void l3mdev_get_saddr(struct net *net, int ifindex,
struct flowi4 *fl4)
static inline int l3mdev_get_saddr(struct net *net, int ifindex,
struct flowi4 *fl4)
{
return 0;
}
static inline

7
include/net/route.h
View File

@ -283,7 +283,12 @@ static inline struct rtable *ip_route_connect(struct flowi4 *fl4,
sport, dport, sk);
if (!src && oif) {
l3mdev_get_saddr(net, oif, fl4);
int rc;
rc = l3mdev_get_saddr(net, oif, fl4);
if (rc < 0)
return ERR_PTR(rc);
src = fl4->saddr;
}
if (!dst || !src) {

7
net/ipv4/raw.c
View File

@ -601,8 +601,11 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
(inet->hdrincl ? FLOWI_FLAG_KNOWN_NH : 0),
daddr, saddr, 0, 0);
if (!saddr && ipc.oif)
l3mdev_get_saddr(net, ipc.oif, &fl4);
if (!saddr && ipc.oif) {
err = l3mdev_get_saddr(net, ipc.oif, &fl4);
if (err < 0)
goto done;
}
if (!inet->hdrincl) {
rfv.msg = msg;

7
net/ipv4/udp.c
View File

@ -1025,8 +1025,11 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
flow_flags,
faddr, saddr, dport, inet->inet_sport);
if (!saddr && ipc.oif)
l3mdev_get_saddr(net, ipc.oif, fl4);
if (!saddr && ipc.oif) {
err = l3mdev_get_saddr(net, ipc.oif, fl4);
if (err < 0)
goto out;
}
security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
rt = ip_route_output_flow(net, fl4, sk);