diff options
| author | David Ahern <dsahern@gmail.com> | 2018-05-21 09:08:14 -0700 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-05-22 10:51:09 +0200 |
| commit | 901731b882d77dc53897aec45015ced42d56fe4c (patch) | |
| tree | 07c27d09002feed8c9429759dc8a1bd844c09e27 /net/ipv6 | |
| parent | 50d889b1789458d1f7d7f40ff4f628b670047773 (diff) | |
| download | talos-obmc-linux-901731b882d77dc53897aec45015ced42d56fe4c.tar.gz talos-obmc-linux-901731b882d77dc53897aec45015ced42d56fe4c.zip | |
net/ipv6: Add helper to return path MTU based on fib result
Determine path MTU from a FIB lookup result. Logic is based on
ip6_dst_mtu_forward plus lookup of nexthop exception.
Add ip6_dst_mtu_forward to ipv6_stubs to handle access by core
bpf code.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/addrconf_core.c | 8 | ||||
| -rw-r--r-- | net/ipv6/af_inet6.c | 1 | ||||
| -rw-r--r-- | net/ipv6/route.c | 48 |
3 files changed, 57 insertions, 0 deletions
diff --git a/net/ipv6/addrconf_core.c b/net/ipv6/addrconf_core.c index 2fe754fd4f5e..5cd0029d930e 100644 --- a/net/ipv6/addrconf_core.c +++ b/net/ipv6/addrconf_core.c @@ -161,12 +161,20 @@ eafnosupport_fib6_multipath_select(const struct net *net, struct fib6_info *f6i, return f6i; } +static u32 +eafnosupport_ip6_mtu_from_fib6(struct fib6_info *f6i, struct in6_addr *daddr, + struct in6_addr *saddr) +{ + return 0; +} + const struct ipv6_stub *ipv6_stub __read_mostly = &(struct ipv6_stub) { .ipv6_dst_lookup = eafnosupport_ipv6_dst_lookup, .fib6_get_table = eafnosupport_fib6_get_table, .fib6_table_lookup = eafnosupport_fib6_table_lookup, .fib6_lookup = eafnosupport_fib6_lookup, .fib6_multipath_select = eafnosupport_fib6_multipath_select, + .ip6_mtu_from_fib6 = eafnosupport_ip6_mtu_from_fib6, }; EXPORT_SYMBOL_GPL(ipv6_stub); diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index 50de8b0d4f70..9ed0eae91758 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -894,6 +894,7 @@ static const struct ipv6_stub ipv6_stub_impl = { .fib6_table_lookup = fib6_table_lookup, .fib6_lookup = fib6_lookup, .fib6_multipath_select = fib6_multipath_select, + .ip6_mtu_from_fib6 = ip6_mtu_from_fib6, .udpv6_encap_enable = udpv6_encap_enable, .ndisc_send_na = ndisc_send_na, .nd_tbl = &nd_tbl, diff --git a/net/ipv6/route.c b/net/ipv6/route.c index cc24ed3bc334..dc5d5c84dbef 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2603,6 +2603,54 @@ out: return mtu - lwtunnel_headroom(dst->lwtstate, mtu); } +/* MTU selection: + * 1. mtu on route is locked - use it + * 2. mtu from nexthop exception + * 3. mtu from egress device + * + * based on ip6_dst_mtu_forward and exception logic of + * rt6_find_cached_rt; called with rcu_read_lock + */ +u32 ip6_mtu_from_fib6(struct fib6_info *f6i, struct in6_addr *daddr, + struct in6_addr *saddr) +{ + struct rt6_exception_bucket *bucket; + struct rt6_exception *rt6_ex; + struct in6_addr *src_key; + struct inet6_dev *idev; + u32 mtu = 0; + + if (unlikely(fib6_metric_locked(f6i, RTAX_MTU))) { + mtu = f6i->fib6_pmtu; + if (mtu) + goto out; + } + + src_key = NULL; +#ifdef CONFIG_IPV6_SUBTREES + if (f6i->fib6_src.plen) + src_key = saddr; +#endif + + bucket = rcu_dereference(f6i->rt6i_exception_bucket); + rt6_ex = __rt6_find_exception_rcu(&bucket, daddr, src_key); + if (rt6_ex && !rt6_check_expired(rt6_ex->rt6i)) + mtu = dst_metric_raw(&rt6_ex->rt6i->dst, RTAX_MTU); + + if (likely(!mtu)) { + struct net_device *dev = fib6_info_nh_dev(f6i); + + mtu = IPV6_MIN_MTU; + idev = __in6_dev_get(dev); + if (idev && idev->cnf.mtu6 > mtu) + mtu = idev->cnf.mtu6; + } + + mtu = min_t(unsigned int, mtu, IP6_MAX_MTU); +out: + return mtu - lwtunnel_headroom(fib6_info_nh_lwt(f6i), mtu); +} + struct dst_entry *icmp6_dst_alloc(struct net_device *dev, struct flowi6 *fl6) { |
