soreuseport: fix ordering for mixed v4/v6 sockets
With the SO_REUSEPORT socket option, it is possible to create sockets
in the AF_INET and AF_INET6 domains which are bound to the same IPv4 address.
This is only possible with SO_REUSEPORT and when not using IPV6_V6ONLY on
the AF_INET6 sockets.
Prior to the commits referenced below, an incoming IPv4 packet would
always be routed to a socket of type AF_INET when this mixed-mode was used.
After those changes, the same packet would be routed to the most recently
bound socket (if this happened to be an AF_INET6 socket, it would
have an IPv4 mapped IPv6 address).
The change in behavior occurred because the recent SO_REUSEPORT optimizations
short-circuit the socket scoring logic as soon as they find a match. They
did not take into account the scoring logic that favors AF_INET sockets
over AF_INET6 sockets in the event of a tie.
To fix this problem, this patch changes the insertion order of AF_INET
and AF_INET6 addresses in the TCP and UDP socket lists when the sockets
have SO_REUSEPORT set. AF_INET sockets will be inserted at the head of the
list and AF_INET6 sockets with SO_REUSEPORT set will always be inserted at
the tail of the list. This will force AF_INET sockets to always be
considered first.
Fixes: e32ea7e747
("soreuseport: fast reuseport UDP socket selection")
Fixes: 125e80b88687 ("soreuseport: fast reuseport TCP socket selection")
Reported-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Craig Gallek <kraig@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
c5b5343cfb
commit
d894ba18d4
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@ -98,6 +98,45 @@ static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n,
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if (!is_a_nulls(first))
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first->pprev = &n->next;
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}
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/**
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* hlist_nulls_add_tail_rcu
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* @n: the element to add to the hash list.
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* @h: the list to add to.
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*
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* Description:
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* Adds the specified element to the end of the specified hlist_nulls,
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* while permitting racing traversals. NOTE: tail insertion requires
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* list traversal.
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*
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* The caller must take whatever precautions are necessary
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* (such as holding appropriate locks) to avoid racing
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* with another list-mutation primitive, such as hlist_nulls_add_head_rcu()
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* or hlist_nulls_del_rcu(), running on this same list.
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* However, it is perfectly legal to run concurrently with
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* the _rcu list-traversal primitives, such as
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* hlist_nulls_for_each_entry_rcu(), used to prevent memory-consistency
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* problems on Alpha CPUs. Regardless of the type of CPU, the
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* list-traversal primitive must be guarded by rcu_read_lock().
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*/
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static inline void hlist_nulls_add_tail_rcu(struct hlist_nulls_node *n,
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struct hlist_nulls_head *h)
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{
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struct hlist_nulls_node *i, *last = NULL;
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for (i = hlist_nulls_first_rcu(h); !is_a_nulls(i);
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i = hlist_nulls_next_rcu(i))
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last = i;
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if (last) {
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n->next = last->next;
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n->pprev = &last->next;
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rcu_assign_pointer(hlist_nulls_next_rcu(last), n);
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} else {
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hlist_nulls_add_head_rcu(n, h);
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}
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}
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/**
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* hlist_nulls_for_each_entry_rcu - iterate over rcu list of given type
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* @tpos: the type * to use as a loop cursor.
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@ -630,7 +630,11 @@ static inline void sk_add_node_rcu(struct sock *sk, struct hlist_head *list)
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static inline void __sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
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{
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hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
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if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
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sk->sk_family == AF_INET6)
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hlist_nulls_add_tail_rcu(&sk->sk_nulls_node, list);
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else
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hlist_nulls_add_head_rcu(&sk->sk_nulls_node, list);
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}
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static inline void sk_nulls_add_node_rcu(struct sock *sk, struct hlist_nulls_head *list)
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@ -339,8 +339,13 @@ found:
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hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
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spin_lock(&hslot2->lock);
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hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
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&hslot2->head);
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if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
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sk->sk_family == AF_INET6)
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hlist_nulls_add_tail_rcu(&udp_sk(sk)->udp_portaddr_node,
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&hslot2->head);
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else
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hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
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&hslot2->head);
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hslot2->count++;
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spin_unlock(&hslot2->lock);
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}
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