Since 0e734419923bd ("ipv4: Use inet_csk_route_child_sock() in DCCP and
TCP."), inet_csk_route_child_sock() is called instead of
inet_csk_route_req().
However, after creating the child-sock in tcp/dccp_v4_syn_recv_sock(),
ireq->opt is set to NULL, before calling inet_csk_route_child_sock().
Thus, inside inet_csk_route_child_sock() opt is always NULL and the
SRR-options are not respected anymore.
Packets sent by the server won't have the correct destination-IP.
This patch fixes it by accessing newinet->inet_opt instead of ireq->opt
inside inet_csk_route_child_sock().
Reported-by: Luca Boccassi <luca.boccassi@gmail.com>
Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
In order to allow prefixed routes, we have to adjust how rt_gateway is set and interpreted. The new interpretation is: 1) rt_gateway == 0, destination is on-link, nexthop is iph->daddr 2) rt_gateway != 0, destination requires a nexthop gateway Abstract the fetching of the proper nexthop value using a new inline helper, rt_nexthop(), as suggested by Joe Perches. Signed-off-by: David S. Miller <davem@davemloft.net> Tested-by: Vijay Subramanian <subramanian.vijay@gmail.com>
free_nh_exceptions() should use rcu_dereference_protected(..., 1) since its called after one RCU grace period. Also add some const-ification in recent code. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This will be used so that we can compose a full flow key. Even though we have a route in this context, we need more. In the future the routes will be without destination address, source address, etc. keying. One ipv4 route will cover entire subnets, etc. In this environment we have to have a way to possess persistent storage for redirects and PMTU information. This persistent storage will exist in the FIB tables, and that's why we'll need to be able to rebuild a full lookup flow key here. Using that flow key will do a fib_lookup() and create/update the persistent entry. Signed-off-by: David S. Miller <davem@davemloft.net>
This abstracts away the call to dst_ops->update_pmtu() so that we can transparently handle the fact that, in the future, the dst itself can be invalidated by the PMTU update (when we have non-host routes cached in sockets). So we try to rebuild the socket cached route after the method invocation if necessary. This isn't used by SCTP because it needs to cache dsts per-transport, and thus will need it's own local version of this helper. Signed-off-by: David S. Miller <davem@davemloft.net>
No longer needed. TCP writes metrics, but now in it's own special cache that does not dirty the route metrics. Therefore there is no longer any reason to pre-cow metrics in this way. Signed-off-by: David S. Miller <davem@davemloft.net>
Don't cache output dst for syncookies, as this adds pressure on IP route cache and rcu subsystem for no gain. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Hans Schillstrom <hans.schillstrom@ericsson.com> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Another problem on SYNFLOOD/DDOS attack is the inetpeer cache getting
larger and larger, using lots of memory and cpu time.
tcp_v4_send_synack()
->inet_csk_route_req()
->ip_route_output_flow()
->rt_set_nexthop()
->rt_init_metrics()
->inet_getpeer( create = true)
This is a side effect of commit a4daad6b09230 (net: Pre-COW metrics for
TCP) added in 2.6.39
Possible solution :
Instruct inet_csk_route_req() to remove FLOWI_FLAG_PRECOW_METRICS
Before patch :
# grep peer /proc/slabinfo
inet_peer_cache 4175430 4175430 192 42 2 : tunables 0 0 0 : slabdata 99415 99415 0
Samples: 41K of event 'cycles', Event count (approx.): 30716565122
+ 20,24% ksoftirqd/0 [kernel.kallsyms] [k] inet_getpeer
+ 8,19% ksoftirqd/0 [kernel.kallsyms] [k] peer_avl_rebalance.isra.1
+ 4,81% ksoftirqd/0 [kernel.kallsyms] [k] sha_transform
+ 3,64% ksoftirqd/0 [kernel.kallsyms] [k] fib_table_lookup
+ 2,36% ksoftirqd/0 [ixgbe] [k] ixgbe_poll
+ 2,16% ksoftirqd/0 [kernel.kallsyms] [k] __ip_route_output_key
+ 2,11% ksoftirqd/0 [kernel.kallsyms] [k] kernel_map_pages
+ 2,11% ksoftirqd/0 [kernel.kallsyms] [k] ip_route_input_common
+ 2,01% ksoftirqd/0 [kernel.kallsyms] [k] __inet_lookup_established
+ 1,83% ksoftirqd/0 [kernel.kallsyms] [k] md5_transform
+ 1,75% ksoftirqd/0 [kernel.kallsyms] [k] check_leaf.isra.9
+ 1,49% ksoftirqd/0 [kernel.kallsyms] [k] ipt_do_table
+ 1,46% ksoftirqd/0 [kernel.kallsyms] [k] hrtimer_interrupt
+ 1,45% ksoftirqd/0 [kernel.kallsyms] [k] kmem_cache_alloc
+ 1,29% ksoftirqd/0 [kernel.kallsyms] [k] inet_csk_search_req
+ 1,29% ksoftirqd/0 [kernel.kallsyms] [k] __netif_receive_skb
+ 1,16% ksoftirqd/0 [kernel.kallsyms] [k] copy_user_generic_string
+ 1,15% ksoftirqd/0 [kernel.kallsyms] [k] kmem_cache_free
+ 1,02% ksoftirqd/0 [kernel.kallsyms] [k] tcp_make_synack
+ 0,93% ksoftirqd/0 [kernel.kallsyms] [k] _raw_spin_lock_bh
+ 0,87% ksoftirqd/0 [kernel.kallsyms] [k] __call_rcu
+ 0,84% ksoftirqd/0 [kernel.kallsyms] [k] rt_garbage_collect
+ 0,84% ksoftirqd/0 [kernel.kallsyms] [k] fib_rules_lookup
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Hans Schillstrom <hans.schillstrom@ericsson.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Name them in a "backward compatible" manner, i.e. reuse or not are still 1 and 0 respectively. The reuse value of 2 means that the socket with it will forcibly reuse everyone else's port. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>