svn commit: r352745 - head/sys/netinet

[Jonathan T. Looney]

Author: jtl
Date: Thu Sep 26 15:06:46 2019
New Revision: 352745
URL: https://svnweb.freebsd.org/changeset/base/352745

Log:
  Access the syncache secret directly from the V_tcp_syncache variable,
  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

Modified:
  head/sys/netinet/tcp_syncache.c

Modified: head/sys/netinet/tcp_syncache.c
==============================================================================
--- head/sys/netinet/tcp_syncache.c	Thu Sep 26 15:02:34 2019	(r352744)
+++ head/sys/netinet/tcp_syncache.c	Thu Sep 26 15:06:46 2019	(r352745)
@@ -2061,8 +2061,6 @@ syncookie_generate(struct syncache_head *sch, struct s
 	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 s
 		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 synca
 	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 synca
 	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);