Date: Wed, 7 Jan 2009 11:44:03 +0000 (UTC) From: Alexander Motin <mav@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-7@freebsd.org Subject: svn commit: r186857 - in stable/7/sys: . contrib/pf crypto/rc4 dev/cxgb Message-ID: <200901071144.n07Bi3A3084743@svn.freebsd.org>
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Author: mav Date: Wed Jan 7 11:44:03 2009 New Revision: 186857 URL: http://svn.freebsd.org/changeset/base/186857 Log: MFC rev. 186179: Avoid 256 integer divisions per rc4_init() call. Replace it with using separate index variable. It gives more then double rc4_init() performance increase on tested i386 P4. It also gives about 15% speedup to PPTP VPN with stateless MPPE encryption (by ng_mppc) which calls rc4_init() for every packet. Modified: stable/7/sys/ (props changed) stable/7/sys/contrib/pf/ (props changed) stable/7/sys/crypto/rc4/rc4.c stable/7/sys/dev/cxgb/ (props changed) Modified: stable/7/sys/crypto/rc4/rc4.c ============================================================================== --- stable/7/sys/crypto/rc4/rc4.c Wed Jan 7 11:19:18 2009 (r186856) +++ stable/7/sys/crypto/rc4/rc4.c Wed Jan 7 11:44:03 2009 (r186857) @@ -61,7 +61,7 @@ void rc4_init(struct rc4_state *const state, const u_char *key, int keylen) { u_char j; - int i; + int i, k; /* Initialize state with identity permutation */ for (i = 0; i < 256; i++) @@ -70,9 +70,11 @@ rc4_init(struct rc4_state *const state, state->index2 = 0; /* Randomize the permutation using key data */ - for (j = i = 0; i < 256; i++) { - j += state->perm[i] + key[i % keylen]; + for (j = i = k = 0; i < 256; i++) { + j += state->perm[i] + key[k]; swap_bytes(&state->perm[i], &state->perm[j]); + if (++k >= keylen) + k = 0; } }
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