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authorWilly Tarreau <w@1wt.eu>2022-05-02 10:46:12 +0200
committerJakub Kicinski <kuba@kernel.org>2022-05-04 19:22:21 -0700
commite9261476184be1abd486c9434164b2acbe0ed6c2 (patch)
treecf9314c7c4e5b15563513dcf9071f4216eb0bd34
parentca7af0402550f9a0b3316d5f1c30904e42ed257d (diff)
downloadlinux-e9261476184be1abd486c9434164b2acbe0ed6c2.tar.bz2
tcp: dynamically allocate the perturb table used by source ports
We'll need to further increase the size of this table and it's likely that at some point its size will not be suitable anymore for a static table. Let's allocate it on boot from inet_hashinfo2_init(), which is called from tcp_init(). Cc: Moshe Kol <moshe.kol@mail.huji.ac.il> Cc: Yossi Gilad <yossi.gilad@mail.huji.ac.il> Cc: Amit Klein <aksecurity@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
-rw-r--r--net/ipv4/inet_hashtables.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 63bb4902f018..48ca07853068 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -731,7 +731,8 @@ EXPORT_SYMBOL_GPL(inet_unhash);
* privacy, this only consumes 1 KB of kernel memory.
*/
#define INET_TABLE_PERTURB_SHIFT 8
-static u32 table_perturb[1 << INET_TABLE_PERTURB_SHIFT];
+#define INET_TABLE_PERTURB_SIZE (1 << INET_TABLE_PERTURB_SHIFT)
+static u32 *table_perturb;
int __inet_hash_connect(struct inet_timewait_death_row *death_row,
struct sock *sk, u64 port_offset,
@@ -774,7 +775,8 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
if (likely(remaining > 1))
remaining &= ~1U;
- net_get_random_once(table_perturb, sizeof(table_perturb));
+ net_get_random_once(table_perturb,
+ INET_TABLE_PERTURB_SIZE * sizeof(*table_perturb));
index = hash_32(port_offset, INET_TABLE_PERTURB_SHIFT);
offset = READ_ONCE(table_perturb[index]) + (port_offset >> 32);
@@ -912,6 +914,12 @@ void __init inet_hashinfo2_init(struct inet_hashinfo *h, const char *name,
low_limit,
high_limit);
init_hashinfo_lhash2(h);
+
+ /* this one is used for source ports of outgoing connections */
+ table_perturb = kmalloc_array(INET_TABLE_PERTURB_SIZE,
+ sizeof(*table_perturb), GFP_KERNEL);
+ if (!table_perturb)
+ panic("TCP: failed to alloc table_perturb");
}
int inet_hashinfo2_init_mod(struct inet_hashinfo *h)