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[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 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> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20121103_114422_584987_87E2326A X-CRM114-Status: GOOD ( 14.23 ) X-Spam-Score: -2.7 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [209.85.210.49 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (akinobu.mita[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature Cc: Theodore Ts'o , Artem Bityutskiy , netdev@vger.kernel.org, Adrian Hunter , Akinobu Mita , linux-mtd@lists.infradead.org, David Woodhouse , Eilon Greenstein X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-mtd-bounces@lists.infradead.org Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.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