From patchwork Tue Nov 13 13:37:01 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Akinobu Mita X-Patchwork-Id: 198680 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id A68E52C00AA for ; Wed, 14 Nov 2012 00:41:15 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754619Ab2KMNhj (ORCPT ); Tue, 13 Nov 2012 08:37:39 -0500 Received: from mail-pa0-f46.google.com ([209.85.220.46]:61949 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754482Ab2KMNhh (ORCPT ); Tue, 13 Nov 2012 08:37:37 -0500 Received: by mail-pa0-f46.google.com with SMTP id hz1so5027345pad.19 for ; Tue, 13 Nov 2012 05:37:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; bh=TJdI8nlRVp4GhnOZRCUmKCs+3zPqb/OxPOYiVEc0i/o=; b=HB5ERQkkljbpZHfomPt6e4ZH+bNbSWAjQxKxWZgmKQZ1UUyobm2ck16vi0+0ucLKGI Rvf/oPh+O4zq4OBwfYbp4/rY7QPtSHlpYfWaQr5HdJrUC9SqWEYMPgU6xy091PWI+RlT nrp1YWTAyRT6cBNyW0xXBHQeQbgH6a2fBuakuOyXnl3glbmogQARvWSCG8xqm0cUuBgN /fri8jmMURE7Y3a+7TTWLxEYJyK1liRbgONuYh9cAFy4abja/fA6i5TtFoponSvU9s1N lrloasnZa47QIk08R/Hb1tNmNigG6d9J+4focND/lgZFRhm1L+3Xly5MigKZbvtALEdu 9joQ== Received: by 10.66.77.39 with SMTP id p7mr64915617paw.8.1352813856989; Tue, 13 Nov 2012 05:37:36 -0800 (PST) Received: from localhost.localdomain (p1120-ipbf2201hodogaya.kanagawa.ocn.ne.jp. [123.220.186.120]) by mx.google.com with ESMTPS id vo8sm5988920pbc.16.2012.11.13.05.37.34 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 13 Nov 2012 05:37:36 -0800 (PST) From: Akinobu Mita To: linux-kernel@vger.kernel.org, akpm@linux-foundation.org Cc: Akinobu Mita , "Theodore Ts'o" , Artem Bityutskiy , Adrian Hunter , David Woodhouse , linux-mtd@lists.infradead.org, Eilon Greenstein , netdev@vger.kernel.org Subject: [PATCH v3 02/11] prandom: introduce prandom_bytes() and prandom_bytes_state() Date: Tue, 13 Nov 2012 22:37:01 +0900 Message-Id: <1352813830-4624-3-git-send-email-akinobu.mita@gmail.com> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1352813830-4624-1-git-send-email-akinobu.mita@gmail.com> References: <1352813830-4624-1-git-send-email-akinobu.mita@gmail.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Add functions to get the requested number of pseudo-random bytes. The difference from get_random_bytes() is that it generates pseudo-random numbers by prandom_u32(). It doesn't consume the entropy pool, and the sequence is reproducible if the same rnd_state is used. So it is suitable for generating random bytes for testing. Signed-off-by: Akinobu Mita Cc: "Theodore Ts'o" Cc: Artem Bityutskiy Cc: Adrian Hunter Cc: David Woodhouse Cc: linux-mtd@lists.infradead.org Cc: Eilon Greenstein Cc: netdev@vger.kernel.org --- * v3 - rename random32_get_bytes_state to prandom_bytes_state - ensure prandom_bytes_state() generates same bytes with same rnd_state * v2 - rename prandom32_get_bytes to random32_get_bytes_state include/linux/random.h | 2 ++ lib/random32.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 51 insertions(+) diff --git a/include/linux/random.h b/include/linux/random.h index db6debc..d984608 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -26,6 +26,7 @@ unsigned int get_random_int(void); unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len); u32 prandom_u32(void); +void prandom_bytes(void *buf, int nbytes); void prandom_seed(u32 seed); /* @@ -36,6 +37,7 @@ void prandom_seed(u32 seed); #define srandom32(seed) prandom_seed(seed) u32 prandom_u32_state(struct rnd_state *); +void prandom_bytes_state(struct rnd_state *state, void *buf, int nbytes); /* * Handle minimum values for seeds diff --git a/lib/random32.c b/lib/random32.c index d1830fa..52280d5 100644 --- a/lib/random32.c +++ b/lib/random32.c @@ -77,6 +77,55 @@ u32 prandom_u32(void) } EXPORT_SYMBOL(prandom_u32); +/* + * prandom_bytes_state - get the requested number of pseudo-random bytes + * + * @state: pointer to state structure holding seeded state. + * @buf: where to copy the pseudo-random bytes to + * @bytes: the requested number of bytes + * + * This is used for pseudo-randomness with no outside seeding. + * For more random results, use prandom_bytes(). + */ +void prandom_bytes_state(struct rnd_state *state, void *buf, int bytes) +{ + unsigned char *p = buf; + int i; + + for (i = 0; i < round_down(bytes, sizeof(u32)); i += sizeof(u32)) { + u32 random = prandom_u32_state(state); + int j; + + for (j = 0; j < sizeof(u32); j++) { + p[i + j] = random; + random >>= BITS_PER_BYTE; + } + } + if (i < bytes) { + u32 random = prandom_u32_state(state); + + for (; i < bytes; i++) { + p[i] = random; + random >>= BITS_PER_BYTE; + } + } +} +EXPORT_SYMBOL(prandom_bytes_state); + +/** + * prandom_bytes - get the requested number of pseudo-random bytes + * @buf: where to copy the pseudo-random bytes to + * @bytes: the requested number of bytes + */ +void prandom_bytes(void *buf, int bytes) +{ + struct rnd_state *state = &get_cpu_var(net_rand_state); + + prandom_bytes_state(state, buf, bytes); + put_cpu_var(state); +} +EXPORT_SYMBOL(prandom_bytes); + /** * prandom_seed - add entropy to pseudo random number generator * @seed: seed value