litmus-rt.git - The LITMUS^RT kernel.

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author	Ingo Molnar <mingo@elte.hu>	2009-02-22 06:06:57 -0500
committer	Ingo Molnar <mingo@elte.hu>	2009-02-25 12:38:07 -0500
commit	3c972c2444dcb7088999c32b8c5a7ab3b8a6c0b6 (patch)
tree	0d89d2cfff1b3b32192ed54c70ee183356a11191 /kernel/time/ntp.c
parent	53bbfa9e9437e70b322368e82c723112d690e304 (diff)

time: ntp: simplify the second_overflow() code flow

Impact: cleanup, no functionality changed Instead of a hierarchy of conditions, transform them to clean gradual conditions and return's. This makes the flow easier to read and makes the purpose of the function easier to understand. kernel/time/ntp.o: text data bss dec hex filename 2552 170 168 2890 b4a ntp.o.before 2552 170 168 2890 b4a ntp.o.after md5: eae1275df0b7d6290c13f6f6f8f05c8c ntp.o.before.asm eae1275df0b7d6290c13f6f6f8f05c8c ntp.o.after.asm Signed-off-by: Ingo Molnar <mingo@elte.hu>

Diffstat (limited to 'kernel/time/ntp.c')

-rw-r--r--

kernel/time/ntp.c

1 files changed, 17 insertions, 12 deletions


diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 3479ec48e604..1fa6615b317a 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c
@@ -232,19 +232,24 @@ void second_overflow(void)
232	time_offset -= time_adj;	232	time_offset -= time_adj;
233	tick_length += time_adj;	233	tick_length += time_adj;
234		234
235	if (unlikely(time_adjust)) {	235	if (!time_adjust)
236	if (time_adjust > MAX_TICKADJ) {	236	return;
237	time_adjust -= MAX_TICKADJ;	237
238	tick_length += MAX_TICKADJ_SCALED;	238	if (time_adjust > MAX_TICKADJ) {
239	} else if (time_adjust < -MAX_TICKADJ) {	239	time_adjust -= MAX_TICKADJ;
240	time_adjust += MAX_TICKADJ;	240	tick_length += MAX_TICKADJ_SCALED;
241	tick_length -= MAX_TICKADJ_SCALED;	241	return;
242	} else {
243	tick_length += (s64)(time_adjust * NSEC_PER_USEC /
244	NTP_INTERVAL_FREQ) << NTP_SCALE_SHIFT;
245	time_adjust = 0;
246	}
247	}	242	}
		243
		244	if (time_adjust < -MAX_TICKADJ) {
		245	time_adjust += MAX_TICKADJ;
		246	tick_length -= MAX_TICKADJ_SCALED;
		247	return;
		248	}
		249
		250	tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ)
		251	<< NTP_SCALE_SHIFT;
		252	time_adjust = 0;
248	}	253	}
249		254
250	#ifdef CONFIG_GENERIC_CMOS_UPDATE	255	#ifdef CONFIG_GENERIC_CMOS_UPDATE

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/* Kerberos-based RxRPC security * * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/module.h> #include <linux/net.h> #include <linux/skbuff.h> #include <linux/udp.h> #include <linux/crypto.h> #include <linux/scatterlist.h> #include <linux/ctype.h> #include <net/sock.h> #include <net/af_rxrpc.h> #define rxrpc_debug rxkad_debug #include "ar-internal.h" #define RXKAD_VERSION 2 #define MAXKRB5TICKETLEN 1024 #define RXKAD_TKT_TYPE_KERBEROS_V5 256 #define ANAME_SZ 40 /* size of authentication name */ #define INST_SZ 40 /* size of principal's instance */ #define REALM_SZ 40 /* size of principal's auth domain */ #define SNAME_SZ 40 /* size of service name */ unsigned rxrpc_debug; module_param_named(debug, rxrpc_debug, uint, S_IWUSR | S_IRUGO); MODULE_PARM_DESC(rxrpc_debug, "rxkad debugging mask"); struct rxkad_level1_hdr { __be32 data_size; /* true data size (excluding padding) */ }; struct rxkad_level2_hdr { __be32 data_size; /* true data size (excluding padding) */ __be32 checksum; /* decrypted data checksum */ }; MODULE_DESCRIPTION("RxRPC network protocol type-2 security (Kerberos)"); MODULE_AUTHOR("Red Hat, Inc."); MODULE_LICENSE("GPL"); /* * this holds a pinned cipher so that keventd doesn't get called by the cipher * alloc routine, but since we have it to hand, we use it to decrypt RESPONSE * packets */ static struct crypto_blkcipher *rxkad_ci; static DEFINE_MUTEX(rxkad_ci_mutex); /* * initialise connection security */ static int rxkad_init_connection_security(struct rxrpc_connection *conn) { struct rxrpc_key_payload *payload; struct crypto_blkcipher *ci; int ret; _enter("{%d},{%x}", conn->debug_id, key_serial(conn->key)); payload = conn->key->payload.data; conn->security_ix = payload->k.security_index; ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC); if (IS_ERR(ci)) { _debug("no cipher"); ret = PTR_ERR(ci); goto error; } if (crypto_blkcipher_setkey(ci, payload->k.session_key, sizeof(payload->k.session_key)) < 0) BUG(); switch (conn->security_level) { case RXRPC_SECURITY_PLAIN: break; case RXRPC_SECURITY_AUTH: conn->size_align = 8; conn->security_size = sizeof(struct rxkad_level1_hdr); conn->header_size += sizeof(struct rxkad_level1_hdr); break; case RXRPC_SECURITY_ENCRYPT: conn->size_align = 8; conn->security_size = sizeof(struct rxkad_level2_hdr); conn->header_size += sizeof(struct rxkad_level2_hdr); break; default: ret = -EKEYREJECTED; goto error; } conn->cipher = ci; ret = 0; error: _leave(" = %d", ret); return ret; } /* * prime the encryption state with the invariant parts of a connection's * description */ static void rxkad_prime_packet_security(struct rxrpc_connection *conn) { struct rxrpc_key_payload *payload; struct blkcipher_desc desc; struct scatterlist sg[2]; struct rxrpc_crypt iv; struct { __be32 x[4]; } tmpbuf __attribute__((aligned(16))); /* must all be in same page */ _enter(""); if (!conn->key) return; payload = conn->key->payload.data; memcpy(&iv, payload->k.session_key, sizeof(iv)); desc.tfm = conn->cipher; desc.info = iv.x; desc.flags = 0; tmpbuf.x[0] = conn->epoch; tmpbuf.x[1] = conn->cid; tmpbuf.x[2] = 0; tmpbuf.x[3] = htonl(conn->security_ix); memset(sg, 0, sizeof(sg)); sg_set_buf(&sg[0], &tmpbuf, sizeof(tmpbuf)); sg_set_buf(&sg[1], &tmpbuf, sizeof(tmpbuf)); crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf)); memcpy(&conn->csum_iv, &tmpbuf.x[2], sizeof(conn->csum_iv)); ASSERTCMP(conn->csum_iv.n[0], ==, tmpbuf.x[2]); _leave(""); } /* * partially encrypt a packet (level 1 security) */ static int rxkad_secure_packet_auth(const struct rxrpc_call *call, struct sk_buff *skb, u32 data_size, void *sechdr) { struct rxrpc_skb_priv *sp; struct blkcipher_desc desc; struct rxrpc_crypt iv; struct scatterlist sg[2]; struct { struct rxkad_level1_hdr hdr; __be32 first; /* first four bytes of data and padding */ } tmpbuf __attribute__((aligned(8))); /* must all be in same page */ u16 check; sp = rxrpc_skb(skb); _enter(""); check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber); data_size |= (u32) check << 16; tmpbuf.hdr.data_size = htonl(data_size); memcpy(&tmpbuf.first, sechdr + 4, sizeof(tmpbuf.first)); /* start the encryption afresh */ memset(&iv, 0, sizeof(iv)); desc.tfm = call->conn->cipher; desc.info = iv.x; desc.flags = 0; memset(sg, 0, sizeof(sg)); sg_set_buf(&sg[0], &tmpbuf, sizeof(tmpbuf)); sg_set_buf(&sg[1], &tmpbuf, sizeof(tmpbuf)); crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf)); memcpy(sechdr, &tmpbuf, sizeof(tmpbuf)); _leave(" = 0"); return 0; } /* * wholly encrypt a packet (level 2 security) */ static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call, struct sk_buff *skb, u32 data_size, void *sechdr) { const struct rxrpc_key_payload *payload; struct rxkad_level2_hdr rxkhdr __attribute__((aligned(8))); /* must be all on one page */ struct rxrpc_skb_priv *sp; struct blkcipher_desc desc; struct rxrpc_crypt iv; struct scatterlist sg[16]; struct sk_buff *trailer; unsigned len; u16 check; int nsg; sp = rxrpc_skb(skb); _enter(""); check = ntohl(sp->hdr.seq ^ sp->hdr.callNumber); rxkhdr.data_size = htonl(data_size | (u32) check << 16); rxkhdr.checksum = 0; /* encrypt from the session key */ payload = call->conn->key->payload.data; memcpy(&iv, payload->k.session_key, sizeof(iv)); desc.tfm = call->conn->cipher; desc.info = iv.x; desc.flags = 0; memset(sg, 0, sizeof(sg[0]) * 2); sg_set_buf(&sg[0], sechdr, sizeof(rxkhdr)); sg_set_buf(&sg[1], &rxkhdr, sizeof(rxkhdr)); crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(rxkhdr)); /* we want to encrypt the skbuff in-place */ nsg = skb_cow_data(skb, 0, &trailer); if (nsg < 0 || nsg > 16) return -ENOMEM; len = data_size + call->conn->size_align - 1; len &= ~(call->conn->size_align - 1); skb_to_sgvec(skb, sg, 0, len); crypto_blkcipher_encrypt_iv(&desc, sg, sg, len); _leave(" = 0"); return 0; } /* * checksum an RxRPC packet header */ static int rxkad_secure_packet(const struct rxrpc_call *call, struct sk_buff *skb, size_t data_size, void *sechdr) { struct rxrpc_skb_priv *sp; struct blkcipher_desc desc; struct rxrpc_crypt iv; struct scatterlist sg[2]; struct { __be32 x[2]; } tmpbuf __attribute__((aligned(8))); /* must all be in same page */ __be32 x; int ret; sp = rxrpc_skb(skb); _enter("{%d{%x}},{#%u},%zu,", call->debug_id, key_serial(call->conn->key), ntohl(sp->hdr.seq), data_size); if (!call->conn->cipher) return 0; ret = key_validate(call->conn->key); if (ret < 0) return ret; /* continue encrypting from where we left off */ memcpy(&iv, call->conn->csum_iv.x, sizeof(iv)); desc.tfm = call->conn->cipher; desc.info = iv.x; desc.flags = 0; /* calculate the security checksum */ x = htonl(call->channel << (32 - RXRPC_CIDSHIFT)); x |= sp->hdr.seq & __constant_cpu_to_be32(0x3fffffff); tmpbuf.x[0] = sp->hdr.callNumber; tmpbuf.x[1] = x; memset(&sg, 0, sizeof(sg)); sg_set_buf(&sg[0], &tmpbuf, sizeof(tmpbuf)); sg_set_buf(&sg[1], &tmpbuf, sizeof(tmpbuf)); crypto_blkcipher_encrypt_iv(&desc, &sg[0], &sg[1], sizeof(tmpbuf)); x = ntohl(tmpbuf.x[1]); x = (x >> 16) & 0xffff; if (x == 0) x = 1; /* zero checksums are not permitted */ sp->hdr.cksum = htons(x); switch (call->conn->security_level) { case RXRPC_SECURITY_PLAIN: ret = 0; break; case RXRPC_SECURITY_AUTH: ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr); break; case RXRPC_SECURITY_ENCRYPT: ret = rxkad_secure_packet_encrypt(call, skb, data_size, sechdr); break; default: ret = -EPERM; break; } _leave(" = %d [set %hx]", ret, x); return ret; } /* * decrypt partial encryption on a packet (level 1 security)


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