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Access the syncache secret directly from the V_tcp_syncache variable,

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rather than indirectly through the backpointer to the tcp_syncache
structure stored in the hashtable bucket.

This also allows us to remove the requirement in syncookie_generate()
and syncookie_lookup() that the syncache hashtable bucket must be
locked.

Reviewed by:	gallatin, rrs
Sponsored by:	Netflix, Inc.
Differential Revision:	https://reviews.freebsd.org/D21644
This commit is contained in:
Jonathan T. Looney 2019-09-26 15:06:46 +00:00
parent 867e98f8ee
commit 0bee4d631a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=352745
1 changed files with 3 additions and 7 deletions
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10
sys/netinet/tcp_syncache.c
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@ -2061,8 +2061,6 @@ syncookie_generate(struct syncache_head *sch, struct syncache *sc)
uint8_t *secbits;
union syncookie cookie;
SCH_LOCK_ASSERT(sch);
cookie.cookie = 0;
/* Map our computed MSS into the 3-bit index. */
@ -2090,10 +2088,10 @@ syncookie_generate(struct syncache_head *sch, struct syncache *sc)
cookie.flags.sack_ok = 1;
/* Which of the two secrets to use. */
secbit = sch->sch_sc->secret.oddeven & 0x1;
secbit = V_tcp_syncache.secret.oddeven & 0x1;
cookie.flags.odd_even = secbit;
secbits = sch->sch_sc->secret.key[secbit];
secbits = V_tcp_syncache.secret.key[secbit];
hash = syncookie_mac(&sc->sc_inc, sc->sc_irs, cookie.cookie, secbits,
(uintptr_t)sch);
@ -2121,8 +2119,6 @@ syncookie_lookup(struct in_conninfo *inc, struct syncache_head *sch,
int wnd, wscale = 0;
union syncookie cookie;
SCH_LOCK_ASSERT(sch);
/*
* Pull information out of SYN-ACK/ACK and revert sequence number
* advances.
@ -2137,7 +2133,7 @@ syncookie_lookup(struct in_conninfo *inc, struct syncache_head *sch,
cookie.cookie = (ack & 0xff) ^ (ack >> 24);
/* Which of the two secrets to use. */
secbits = sch->sch_sc->secret.key[cookie.flags.odd_even];
secbits = V_tcp_syncache.secret.key[cookie.flags.odd_even];
hash = syncookie_mac(inc, seq, cookie.cookie, secbits, (uintptr_t)sch);