diff options
| author | Gerrit Renker <gerrit@erg.abdn.ac.uk> | 2007-03-20 18:26:51 +0300 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-04-26 09:26:42 +0400 |
| commit | 6b811d43f6cc9eccdfc011a99f8571df2abc46d1 (patch) | |
| tree | 58e7f27415faf9ad6761bab6e51a7003139190f9 /net/dccp/dccp.h | |
| parent | 8b5be26831b973d8013e8b4c9860d9694310cdc6 (diff) | |
| download | linux-6b811d43f6cc9eccdfc011a99f8571df2abc46d1.tar.xz | |
[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 <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp/dccp.h')
| -rw-r--r-- | net/dccp/dccp.h | 47 |
1 files changed, 27 insertions, 20 deletions
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h index e33a9edb4036..a2c20a265b25 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) { |