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linux_dsm_epyc7002/include/net/ip6_route.h
Stefano Brivio 1e47b4837f ipv6: Dump route exceptions if requested 
Since commit 2b760fcf5c ("ipv6: hook up exception table to store dst
cache"), route exceptions reside in a separate hash table, and won't be
found by walking the FIB, so they won't be dumped to userspace on a
RTM_GETROUTE message.

This causes 'ip -6 route list cache' and 'ip -6 route flush cache' to
have no function anymore:

 # ip -6 route get fc00:3::1
 fc00:3::1 via fc00:1::2 dev veth_A-R1 src fc00:1::1 metric 1024 expires 539sec mtu 1400 pref medium
 # ip -6 route get fc00:4::1
 fc00:4::1 via fc00:2::2 dev veth_A-R2 src fc00:2::1 metric 1024 expires 536sec mtu 1500 pref medium
 # ip -6 route list cache
 # ip -6 route flush cache
 # ip -6 route get fc00:3::1
 fc00:3::1 via fc00:1::2 dev veth_A-R1 src fc00:1::1 metric 1024 expires 520sec mtu 1400 pref medium
 # ip -6 route get fc00:4::1
 fc00:4::1 via fc00:2::2 dev veth_A-R2 src fc00:2::1 metric 1024 expires 519sec mtu 1500 pref medium

because iproute2 lists cached routes using RTM_GETROUTE, and flushes them
by listing all the routes, and deleting them with RTM_DELROUTE one by one.

If cached routes are requested using the RTM_F_CLONED flag together with
strict checking, or if no strict checking is requested (and hence we can't
consistently apply filters), look up exceptions in the hash table
associated with the current fib6_info in rt6_dump_route(), and, if present
and not expired, add them to the dump.

We might be unable to dump all the entries for a given node in a single
message, so keep track of how many entries were handled for the current
node in fib6_walker, and skip that amount in case we start from the same
partially dumped node.

When a partial dump restarts, as the starting node might change when
'sernum' changes, we have no guarantee that we need to skip the same
amount of in-node entries. Therefore, we need two counters, and we need to
zero the in-node counter if the node from which the dump is resumed
differs.

Note that, with the current version of iproute2, this only fixes the
'ip -6 route list cache': on a flush command, iproute2 doesn't pass
RTM_F_CLONED and, due to this inconsistency, 'ip -6 route flush cache' is
still unable to fetch the routes to be flushed. This will be addressed in
a patch for iproute2.

To flush cached routes, a procfs entry could be introduced instead: that's
how it works for IPv4. We already have a rt6_flush_exception() function
ready to be wired to it. However, this would not solve the issue for
listing.

Versions of iproute2 and kernel tested:

                    iproute2
kernel             4.14.0   4.15.0   4.19.0   5.0.0   5.1.0    5.1.0, patched
 3.18    list        +        +        +        +       +            +
         flush       +        +        +        +       +            +
 4.4     list        +        +        +        +       +            +
         flush       +        +        +        +       +            +
 4.9     list        +        +        +        +       +            +
         flush       +        +        +        +       +            +
 4.14    list        +        +        +        +       +            +
         flush       +        +        +        +       +            +
 4.15    list
         flush
 4.19    list
         flush
 5.0     list
         flush
 5.1     list
         flush
 with    list        +        +        +        +       +            +
 fix     flush       +        +        +                             +

v7:
  - Explain usage of "skip" counters in commit message (suggested by
    David Ahern)

v6:
  - Rebase onto net-next, use recently introduced nexthop walker
  - Make rt6_nh_dump_exceptions() a separate function (suggested by David
    Ahern)

v5:
  - Use dump_routes and dump_exceptions from filter, ignore NLM_F_MATCH,
    update test results (flushing works with iproute2 < 5.0.0 now)

v4:
  - Split NLM_F_MATCH and strict check handling in separate patches
  - Filter routes using RTM_F_CLONED: if it's not set, only return
    non-cached routes, and if it's set, only return cached routes:
    change requested by David Ahern and Martin Lau. This implies that
    iproute2 needs a separate patch to be able to flush IPv6 cached
    routes. This is not ideal because we can't fix the breakage caused
    by 2b760fcf5c entirely in kernel. However, two years have passed
    since then, and this makes it more tolerable

v3:
  - More descriptive comment about expired exceptions in rt6_dump_route()
  - Swap return values of rt6_dump_route() (suggested by Martin Lau)
  - Don't zero skip_in_node in case we don't dump anything in a given pass
    (also suggested by Martin Lau)
  - Remove check on RTM_F_CLONED altogether: in the current UAPI semantic,
    it's just a flag to indicate the route was cloned, not to filter on
    routes

v2: Add tracking of number of entries to be skipped in current node after
    a partial dump. As we restart from the same node, if not all the
    exceptions for a given node fit in a single message, the dump will
    not terminate, as suggested by Martin Lau. This is a concrete
    possibility, setting up a big number of exceptions for the same route
    actually causes the issue, suggested by David Ahern.

Reported-by: Jianlin Shi <jishi@redhat.com>
Fixes: 2b760fcf5c ("ipv6: hook up exception table to store dst cache")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-24 10:18:49 -07:00

338 lines
9.7 KiB
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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _NET_IP6_ROUTE_H
#define _NET_IP6_ROUTE_H
struct route_info {
__u8 type;
__u8 length;
__u8 prefix_len;
#if defined(__BIG_ENDIAN_BITFIELD)
__u8 reserved_h:3,
route_pref:2,
reserved_l:3;
#elif defined(__LITTLE_ENDIAN_BITFIELD)
__u8 reserved_l:3,
route_pref:2,
reserved_h:3;
#endif
__be32 lifetime;
__u8 prefix[0]; /* 0,8 or 16 */
};
#include <net/addrconf.h>
#include <net/flow.h>
#include <net/ip6_fib.h>
#include <net/sock.h>
#include <net/lwtunnel.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/route.h>
#include <net/nexthop.h>
#define RT6_LOOKUP_F_IFACE 0x00000001
#define RT6_LOOKUP_F_REACHABLE 0x00000002
#define RT6_LOOKUP_F_HAS_SADDR 0x00000004
#define RT6_LOOKUP_F_SRCPREF_TMP 0x00000008
#define RT6_LOOKUP_F_SRCPREF_PUBLIC 0x00000010
#define RT6_LOOKUP_F_SRCPREF_COA 0x00000020
#define RT6_LOOKUP_F_IGNORE_LINKSTATE 0x00000040
#define RT6_LOOKUP_F_DST_NOREF 0x00000080
/* We do not (yet ?) support IPv6 jumbograms (RFC 2675)
* Unlike IPv4, hdr->seg_len doesn't include the IPv6 header
*/
#define IP6_MAX_MTU (0xFFFF + sizeof(struct ipv6hdr))
/*
* rt6_srcprefs2flags() and rt6_flags2srcprefs() translate
* between IPV6_ADDR_PREFERENCES socket option values
* IPV6_PREFER_SRC_TMP = 0x1
* IPV6_PREFER_SRC_PUBLIC = 0x2
* IPV6_PREFER_SRC_COA = 0x4
* and above RT6_LOOKUP_F_SRCPREF_xxx flags.
*/
static inline int rt6_srcprefs2flags(unsigned int srcprefs)
{
/* No need to bitmask because srcprefs have only 3 bits. */
return srcprefs << 3;
}
static inline unsigned int rt6_flags2srcprefs(int flags)
{
return (flags >> 3) & 7;
}
static inline bool rt6_need_strict(const struct in6_addr *daddr)
{
return ipv6_addr_type(daddr) &
(IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL | IPV6_ADDR_LOOPBACK);
}
/* fib entries using a nexthop object can not be coalesced into
* a multipath route
*/
static inline bool rt6_qualify_for_ecmp(const struct fib6_info *f6i)
{
/* the RTF_ADDRCONF flag filters out RA's */
return !(f6i->fib6_flags & RTF_ADDRCONF) && !f6i->nh &&
f6i->fib6_nh->fib_nh_gw_family;
}
void ip6_route_input(struct sk_buff *skb);
struct dst_entry *ip6_route_input_lookup(struct net *net,
struct net_device *dev,
struct flowi6 *fl6,
const struct sk_buff *skb, int flags);
struct dst_entry *ip6_route_output_flags_noref(struct net *net,
const struct sock *sk,
struct flowi6 *fl6, int flags);
struct dst_entry *ip6_route_output_flags(struct net *net, const struct sock *sk,
struct flowi6 *fl6, int flags);
static inline struct dst_entry *ip6_route_output(struct net *net,
const struct sock *sk,
struct flowi6 *fl6)
{
return ip6_route_output_flags(net, sk, fl6, 0);
}
/* Only conditionally release dst if flags indicates
* !RT6_LOOKUP_F_DST_NOREF or dst is in uncached_list.
*/
static inline void ip6_rt_put_flags(struct rt6_info *rt, int flags)
{
if (!(flags & RT6_LOOKUP_F_DST_NOREF) ||
!list_empty(&rt->rt6i_uncached))
ip6_rt_put(rt);
}
struct dst_entry *ip6_route_lookup(struct net *net, struct flowi6 *fl6,
const struct sk_buff *skb, int flags);
struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
int ifindex, struct flowi6 *fl6,
const struct sk_buff *skb, int flags);
void ip6_route_init_special_entries(void);
int ip6_route_init(void);
void ip6_route_cleanup(void);
int ipv6_route_ioctl(struct net *net, unsigned int cmd, void __user *arg);
int ip6_route_add(struct fib6_config *cfg, gfp_t gfp_flags,
struct netlink_ext_ack *extack);
int ip6_ins_rt(struct net *net, struct fib6_info *f6i);
int ip6_del_rt(struct net *net, struct fib6_info *f6i);
void rt6_flush_exceptions(struct fib6_info *f6i);
void rt6_age_exceptions(struct fib6_info *f6i, struct fib6_gc_args *gc_args,
unsigned long now);
static inline int ip6_route_get_saddr(struct net *net, struct fib6_info *f6i,
const struct in6_addr *daddr,
unsigned int prefs,
struct in6_addr *saddr)
{
int err = 0;
if (f6i && f6i->fib6_prefsrc.plen) {
*saddr = f6i->fib6_prefsrc.addr;
} else {
struct net_device *dev = f6i ? fib6_info_nh_dev(f6i) : NULL;
err = ipv6_dev_get_saddr(net, dev, daddr, prefs, saddr);
}
return err;
}
struct rt6_info *rt6_lookup(struct net *net, const struct in6_addr *daddr,
const struct in6_addr *saddr, int oif,
const struct sk_buff *skb, int flags);
u32 rt6_multipath_hash(const struct net *net, const struct flowi6 *fl6,
const struct sk_buff *skb, struct flow_keys *hkeys);
struct dst_entry *icmp6_dst_alloc(struct net_device *dev, struct flowi6 *fl6);
void fib6_force_start_gc(struct net *net);
struct fib6_info *addrconf_f6i_alloc(struct net *net, struct inet6_dev *idev,
const struct in6_addr *addr, bool anycast,
gfp_t gfp_flags);
struct rt6_info *ip6_dst_alloc(struct net *net, struct net_device *dev,
int flags);
/*
* support functions for ND
*
*/
struct fib6_info *rt6_get_dflt_router(struct net *net,
const struct in6_addr *addr,
struct net_device *dev);
struct fib6_info *rt6_add_dflt_router(struct net *net,
const struct in6_addr *gwaddr,
struct net_device *dev, unsigned int pref);
void rt6_purge_dflt_routers(struct net *net);
int rt6_route_rcv(struct net_device *dev, u8 *opt, int len,
const struct in6_addr *gwaddr);
void ip6_update_pmtu(struct sk_buff *skb, struct net *net, __be32 mtu, int oif,
u32 mark, kuid_t uid);
void ip6_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, __be32 mtu);
void ip6_redirect(struct sk_buff *skb, struct net *net, int oif, u32 mark,
kuid_t uid);
void ip6_redirect_no_header(struct sk_buff *skb, struct net *net, int oif);
void ip6_sk_redirect(struct sk_buff *skb, struct sock *sk);
struct netlink_callback;
struct rt6_rtnl_dump_arg {
struct sk_buff *skb;
struct netlink_callback *cb;
struct net *net;
struct fib_dump_filter filter;
};
int rt6_dump_route(struct fib6_info *f6i, void *p_arg, unsigned int skip);
void rt6_mtu_change(struct net_device *dev, unsigned int mtu);
void rt6_remove_prefsrc(struct inet6_ifaddr *ifp);
void rt6_clean_tohost(struct net *net, struct in6_addr *gateway);
void rt6_sync_up(struct net_device *dev, unsigned char nh_flags);
void rt6_disable_ip(struct net_device *dev, unsigned long event);
void rt6_sync_down_dev(struct net_device *dev, unsigned long event);
void rt6_multipath_rebalance(struct fib6_info *f6i);
void rt6_uncached_list_add(struct rt6_info *rt);
void rt6_uncached_list_del(struct rt6_info *rt);
static inline const struct rt6_info *skb_rt6_info(const struct sk_buff *skb)
{
const struct dst_entry *dst = skb_dst(skb);
const struct rt6_info *rt6 = NULL;
if (dst)
rt6 = container_of(dst, struct rt6_info, dst);
return rt6;
}
/*
* Store a destination cache entry in a socket
*/
static inline void ip6_dst_store(struct sock *sk, struct dst_entry *dst,
const struct in6_addr *daddr,
const struct in6_addr *saddr)
{
struct ipv6_pinfo *np = inet6_sk(sk);
np->dst_cookie = rt6_get_cookie((struct rt6_info *)dst);
sk_setup_caps(sk, dst);
np->daddr_cache = daddr;
#ifdef CONFIG_IPV6_SUBTREES
np->saddr_cache = saddr;
#endif
}
void ip6_sk_dst_store_flow(struct sock *sk, struct dst_entry *dst,
const struct flowi6 *fl6);
static inline bool ipv6_unicast_destination(const struct sk_buff *skb)
{
struct rt6_info *rt = (struct rt6_info *) skb_dst(skb);
return rt->rt6i_flags & RTF_LOCAL;
}
static inline bool ipv6_anycast_destination(const struct dst_entry *dst,
const struct in6_addr *daddr)
{
struct rt6_info *rt = (struct rt6_info *)dst;
return rt->rt6i_flags & RTF_ANYCAST ||
(rt->rt6i_dst.plen < 127 &&
ipv6_addr_equal(&rt->rt6i_dst.addr, daddr));
}
int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
int (*output)(struct net *, struct sock *, struct sk_buff *));
static inline int ip6_skb_dst_mtu(struct sk_buff *skb)
{
struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ?
inet6_sk(skb->sk) : NULL;
return (np && np->pmtudisc >= IPV6_PMTUDISC_PROBE) ?
skb_dst(skb)->dev->mtu : dst_mtu(skb_dst(skb));
}
static inline bool ip6_sk_accept_pmtu(const struct sock *sk)
{
return inet6_sk(sk)->pmtudisc != IPV6_PMTUDISC_INTERFACE &&
inet6_sk(sk)->pmtudisc != IPV6_PMTUDISC_OMIT;
}
static inline bool ip6_sk_ignore_df(const struct sock *sk)
{
return inet6_sk(sk)->pmtudisc < IPV6_PMTUDISC_DO ||
inet6_sk(sk)->pmtudisc == IPV6_PMTUDISC_OMIT;
}
static inline struct in6_addr *rt6_nexthop(struct rt6_info *rt,
struct in6_addr *daddr)
{
if (rt->rt6i_flags & RTF_GATEWAY)
return &rt->rt6i_gateway;
else if (unlikely(rt->rt6i_flags & RTF_CACHE))
return &rt->rt6i_dst.addr;
else
return daddr;
}
static inline bool rt6_duplicate_nexthop(struct fib6_info *a, struct fib6_info *b)
{
struct fib6_nh *nha, *nhb;
if (a->nh || b->nh)
return nexthop_cmp(a->nh, b->nh);
nha = a->fib6_nh;
nhb = b->fib6_nh;
return nha->fib_nh_dev == nhb->fib_nh_dev &&
ipv6_addr_equal(&nha->fib_nh_gw6, &nhb->fib_nh_gw6) &&
!lwtunnel_cmp_encap(nha->fib_nh_lws, nhb->fib_nh_lws);
}
static inline unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst)
{
struct inet6_dev *idev;
unsigned int mtu;
if (dst_metric_locked(dst, RTAX_MTU)) {
mtu = dst_metric_raw(dst, RTAX_MTU);
if (mtu)
return mtu;
}
mtu = IPV6_MIN_MTU;
rcu_read_lock();
idev = __in6_dev_get(dst->dev);
if (idev)
mtu = idev->cnf.mtu6;
rcu_read_unlock();
return mtu;
}
u32 ip6_mtu_from_fib6(const struct fib6_result *res,
const struct in6_addr *daddr,
const struct in6_addr *saddr);
struct neighbour *ip6_neigh_lookup(const struct in6_addr *gw,
struct net_device *dev, struct sk_buff *skb,
const void *daddr);
#endif
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