From patchwork Sat Nov 3 15:43:33 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Akinobu Mita X-Patchwork-Id: 196860 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 C11962C00B2 for ; Sun, 4 Nov 2012 02:46:40 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756456Ab2KCPoX (ORCPT ); Sat, 3 Nov 2012 11:44:23 -0400 Received: from mail-da0-f46.google.com ([209.85.210.46]:48484 "EHLO mail-da0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756421Ab2KCPoV (ORCPT ); Sat, 3 Nov 2012 11:44:21 -0400 Received: by mail-da0-f46.google.com with SMTP id n41so2059048dak.19 for ; Sat, 03 Nov 2012 08:44:20 -0700 (PDT) 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=0vPmQvqoG+BiHUlXh0VqjyYW3ax5f5aMNSq2TKXZahw=; b=XLFeNeFGn0e1cyUWQ4p4eeq/gSjMm0tdyb+crk5x6x9OnmNHyB2m6xH3j8g8W0vdsj HPDfI0huZuVAUwRaVdU9nsIJIT6Rvm5u+HoY4rUn2QDHC25vBpByGqkKdvpLpIh51x3w plNZnSUL5FnWtY/+l9EyUxfaGZ0dg6HWVsEKvumCudvaThUFt7+avCmJjOi3ST1Px5YX FaqlQ0/W5zs0LkASjMQ3c5mas13jLrKB4toa2Hnm/+URAHnij5FPzOQ3cENWwe9KjDWp we+VAc9MGaqFOZanw9xO1igt2nU0PZCaTB8sOptDAn2Wnofjr5NHuz8VRBh53XtzwGPX k6Jg== Received: by 10.66.81.138 with SMTP id a10mr14744503pay.53.1351957460899; Sat, 03 Nov 2012 08:44:20 -0700 (PDT) Received: from localhost.localdomain (p1120-ipbf2201hodogaya.kanagawa.ocn.ne.jp. [123.220.186.120]) by mx.google.com with ESMTPS id qi2sm7546049pbc.22.2012.11.03.08.44.18 (version=TLSv1/SSLv3 cipher=OTHER); Sat, 03 Nov 2012 08:44:20 -0700 (PDT) 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 v2 02/11] random32: introduce random32_get_bytes() and random32_get_bytes_state() Date: Sun, 4 Nov 2012 00:43:33 +0900 Message-Id: <1351957422-23243-3-git-send-email-akinobu.mita@gmail.com> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1351957422-23243-1-git-send-email-akinobu.mita@gmail.com> References: <1351957422-23243-1-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 random32(). It is fast, suitable for generating random bytes for testing, and reproducible if random32_get_bytes_state() is used. 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 --- * v2 - rename prandom32_get_bytes to random32_get_bytes_state include/linux/random.h | 2 ++ lib/random32.c | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 40 insertions(+) diff --git a/include/linux/random.h b/include/linux/random.h index bb96f79..4176762 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -27,8 +27,10 @@ unsigned long randomize_range(unsigned long start, unsigned long end, unsigned l u32 random32(void); void srandom32(u32 seed); +void random32_get_bytes(void *buf, int nbytes); u32 random32_state(struct rnd_state *); +void random32_get_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 7a3e0c7..9557417 100644 --- a/lib/random32.c +++ b/lib/random32.c @@ -61,6 +61,44 @@ u32 random32_state(struct rnd_state *state) EXPORT_SYMBOL(random32_state); /** + * random32_get_bytes_state - get the 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 random32_get_bytes(). + */ +void random32_get_bytes_state(struct rnd_state *state, void *buf, int bytes) +{ + unsigned char *p = buf; + + for (; bytes > 0 && ((unsigned long)p) % sizeof(u32); bytes--, p++) + *p = random32_state(state); + + for (; bytes > sizeof(u32) - 1; bytes -= sizeof(u32), p += sizeof(u32)) + *(u32 *)p = random32_state(state); + + for (; bytes > 0; bytes--, p++) + *p = random32_state(state); +} +EXPORT_SYMBOL(random32_get_bytes_state); + +/** + * random32_get_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 random32_get_bytes(void *buf, int bytes) +{ + struct rnd_state *state = &get_cpu_var(net_rand_state); + + random32_get_bytes_state(state, buf, bytes); + put_cpu_var(state); +} +EXPORT_SYMBOL(random32_get_bytes); + +/** * random32 - pseudo random number generator * * A 32 bit pseudo-random number is generated using a fast