From: Gerrit Renker Date: Tue, 20 Mar 2007 15:26:51 +0000 (-0300) Subject: [DCCP]: 48-bit sequence number arithmetic X-Git-Tag: v2.6.22-rc1~1128^2~245 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6b811d43f6cc9eccdfc011a99f8571df2abc46d1;p=linux-2.6 [DCCP]: 48-bit sequence number arithmetic This patch * organizes the sequence arithmetic functions into one corner of dccp.h * performs a small modification of dccp_set_seqno to make it more widely reusable (now it is safe to use any number, since it performs modulo-2^48 assignment) * adds functions and generic macros for 48-bit sequence arithmetic: --48 bit complement --modulo-48 addition and modulo-48 subtraction --dccp_inc_seqno now a special case of add48 Constants renamed following a suggestion by Arnaldo. Signed-off-by: Gerrit Renker Acked-by: Ian McDonald Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller --- diff --git a/net/dccp/ackvec.c b/net/dccp/ackvec.c index a086c6312d..01030f3461 100644 --- a/net/dccp/ackvec.c +++ b/net/dccp/ackvec.c @@ -157,7 +157,7 @@ struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority) if (av != NULL) { av->dccpav_buf_head = DCCP_MAX_ACKVEC_LEN - 1; - av->dccpav_buf_ackno = DCCP_MAX_SEQNO + 1; + av->dccpav_buf_ackno = UINT48_MAX + 1; av->dccpav_buf_nonce = av->dccpav_buf_nonce = 0; av->dccpav_time.tv_sec = 0; av->dccpav_time.tv_usec = 0; diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h index e33a9edb40..a2c20a265b 100644 --- a/net/dccp/dccp.h +++ b/net/dccp/dccp.h @@ -92,6 +92,32 @@ extern int sysctl_dccp_feat_send_ack_vector; extern int sysctl_dccp_feat_send_ndp_count; extern int sysctl_dccp_tx_qlen; +/* + * 48-bit sequence number arithmetic (signed and unsigned) + */ +#define INT48_MIN 0x800000000000LL /* 2^47 */ +#define UINT48_MAX 0xFFFFFFFFFFFFLL /* 2^48 - 1 */ +#define COMPLEMENT48(x) (0x1000000000000LL - (x)) /* 2^48 - x */ +#define TO_SIGNED48(x) (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x))) +#define TO_UNSIGNED48(x) (((x) >= 0)? (x) : COMPLEMENT48(-(x))) +#define ADD48(a, b) (((a) + (b)) & UINT48_MAX) +#define SUB48(a, b) ADD48((a), COMPLEMENT48(b)) + +static inline void dccp_set_seqno(u64 *seqno, u64 value) +{ + *seqno = value & UINT48_MAX; +} + +static inline void dccp_inc_seqno(u64 *seqno) +{ + *seqno = ADD48(*seqno, 1); +} + +static inline u64 dccp_delta_seqno(u64 seqno1, u64 seqno2) +{ + return ((seqno2 << 16) - (seqno1 << 16)) >> 16; +} + /* is seq1 < seq2 ? */ static inline int before48(const u64 seq1, const u64 seq2) { @@ -313,26 +339,7 @@ static inline int dccp_packet_without_ack(const struct sk_buff *skb) return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST; } -#define DCCP_MAX_SEQNO ((((u64)1) << 48) - 1) -#define DCCP_PKT_WITHOUT_ACK_SEQ (DCCP_MAX_SEQNO << 2) - -static inline void dccp_set_seqno(u64 *seqno, u64 value) -{ - if (value > DCCP_MAX_SEQNO) - value -= DCCP_MAX_SEQNO + 1; - *seqno = value; -} - -static inline u64 dccp_delta_seqno(u64 seqno1, u64 seqno2) -{ - return ((seqno2 << 16) - (seqno1 << 16)) >> 16; -} - -static inline void dccp_inc_seqno(u64 *seqno) -{ - if (++*seqno > DCCP_MAX_SEQNO) - *seqno = 0; -} +#define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2) static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss) {