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6f4e5fff1e
linux/net/dccp/dccp.h
Gerrit Renker 6f4e5fff1e [DCCP]: Support for partial checksums (RFC 4340, sec. 9.2) 
This patch does the following:
  a) introduces variable-length checksums as specified in [RFC 4340, sec. 9.2]
  b) provides necessary socket options and documentation as to how to use them
  c) basic support and infrastructure for the Minimum Checksum Coverage feature
     [RFC 4340, sec. 9.2.1]: acceptability tests, user notification and user
     interface

In addition, it

 (1) fixes two bugs in the DCCPv4 checksum computation:
 	* pseudo-header used checksum_len instead of skb->len
	* incorrect checksum coverage calculation based on dccph_x
 (2) removes dccp_v4_verify_checksum() since it reduplicates code of the
     checksum computation; code calling this function is updated accordingly.
 (3) now uses skb_checksum(), which is safer than checksum_partial() if the
     sk_buff has is a non-linear buffer (has pages attached to it).
 (4) fixes an outstanding TODO item:
        * If P.CsCov is too large for the packet size, drop packet and return.

The code has been tested with applications, the latest version of tcpdump now
comes with support for partial DCCP checksums.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-12-02 21:22:09 -08:00

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#ifndef _DCCP_H
#define _DCCP_H
/*
* net/dccp/dccp.h
*
* An implementation of the DCCP protocol
* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
* Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/dccp.h>
#include <net/snmp.h>
#include <net/sock.h>
#include <net/tcp.h>
#include "ackvec.h"
#ifdef CONFIG_IP_DCCP_DEBUG
extern int dccp_debug;
#define dccp_pr_debug(format, a...) \
do { if (dccp_debug) \
printk(KERN_DEBUG "%s: " format, __FUNCTION__ , ##a); \
} while (0)
#define dccp_pr_debug_cat(format, a...) do { if (dccp_debug) \
printk(format, ##a); } while (0)
#else
#define dccp_pr_debug(format, a...)
#define dccp_pr_debug_cat(format, a...)
#endif
extern struct inet_hashinfo dccp_hashinfo;
extern atomic_t dccp_orphan_count;
extern void dccp_time_wait(struct sock *sk, int state, int timeo);
/*
* Set safe upper bounds for header and option length. Since Data Offset is 8
* bits (RFC 4340, sec. 5.1), the total header length can never be more than
* 4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1):
* - DCCP-Response with ACK Subheader and 4 bytes of Service code OR
* - DCCP-Reset with ACK Subheader and 4 bytes of Reset Code fields
* Hence a safe upper bound for the maximum option length is 1020-28 = 992
*/
#define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(int))
#define DCCP_MAX_PACKET_HDR 28
#define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR)
#define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER)
#define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
* state, about 60 seconds */
/* RFC 1122, 4.2.3.1 initial RTO value */
#define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))
/* Maximal interval between probes for local resources. */
#define DCCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ / 2U))
#define DCCP_RTO_MAX ((unsigned)(120 * HZ)) /* FIXME: using TCP value */
#define DCCP_XMIT_TIMEO 30000 /* Time/msecs for blocking transmit per packet */
/* is seq1 < seq2 ? */
static inline int before48(const u64 seq1, const u64 seq2)
{
return (s64)((seq1 << 16) - (seq2 << 16)) < 0;
}
/* is seq1 > seq2 ? */
static inline int after48(const u64 seq1, const u64 seq2)
{
return (s64)((seq2 << 16) - (seq1 << 16)) < 0;
}
/* is seq2 <= seq1 <= seq3 ? */
static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
{
return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
}
static inline u64 max48(const u64 seq1, const u64 seq2)
{
return after48(seq1, seq2) ? seq1 : seq2;
}
/* is seq1 next seqno after seq2 */
static inline int follows48(const u64 seq1, const u64 seq2)
{
int diff = (seq1 & 0xFFFF) - (seq2 & 0xFFFF);
return diff==1;
}
enum {
DCCP_MIB_NUM = 0,
DCCP_MIB_ACTIVEOPENS, /* ActiveOpens */
DCCP_MIB_ESTABRESETS, /* EstabResets */
DCCP_MIB_CURRESTAB, /* CurrEstab */
DCCP_MIB_OUTSEGS, /* OutSegs */
DCCP_MIB_OUTRSTS,
DCCP_MIB_ABORTONTIMEOUT,
DCCP_MIB_TIMEOUTS,
DCCP_MIB_ABORTFAILED,
DCCP_MIB_PASSIVEOPENS,
DCCP_MIB_ATTEMPTFAILS,
DCCP_MIB_OUTDATAGRAMS,
DCCP_MIB_INERRS,
DCCP_MIB_OPTMANDATORYERROR,
DCCP_MIB_INVALIDOPT,
__DCCP_MIB_MAX
};
#define DCCP_MIB_MAX __DCCP_MIB_MAX
struct dccp_mib {
unsigned long mibs[DCCP_MIB_MAX];
} __SNMP_MIB_ALIGN__;
DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
#define DCCP_INC_STATS(field) SNMP_INC_STATS(dccp_statistics, field)
#define DCCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(dccp_statistics, field)
#define DCCP_INC_STATS_USER(field) SNMP_INC_STATS_USER(dccp_statistics, field)
#define DCCP_DEC_STATS(field) SNMP_DEC_STATS(dccp_statistics, field)
#define DCCP_ADD_STATS_BH(field, val) \
SNMP_ADD_STATS_BH(dccp_statistics, field, val)
#define DCCP_ADD_STATS_USER(field, val) \
SNMP_ADD_STATS_USER(dccp_statistics, field, val)
/*
* Checksumming routines
*/
static inline int dccp_csum_coverage(const struct sk_buff *skb)
{
const struct dccp_hdr* dh = dccp_hdr(skb);
if (dh->dccph_cscov == 0)
return skb->len;
return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32);
}
static inline void dccp_csum_outgoing(struct sk_buff *skb)
{
int cov = dccp_csum_coverage(skb);
if (cov >= skb->len)
dccp_hdr(skb)->dccph_cscov = 0;
skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0);
}
extern void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
extern int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb);
extern void dccp_send_ack(struct sock *sk);
extern void dccp_send_delayed_ack(struct sock *sk);
extern void dccp_reqsk_send_ack(struct sk_buff *sk, struct request_sock *rsk);
extern void dccp_send_sync(struct sock *sk, const u64 seq,
const enum dccp_pkt_type pkt_type);
extern void dccp_write_xmit(struct sock *sk, int block);
extern void dccp_write_space(struct sock *sk);
extern void dccp_init_xmit_timers(struct sock *sk);
static inline void dccp_clear_xmit_timers(struct sock *sk)
{
inet_csk_clear_xmit_timers(sk);
}
extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
extern const char *dccp_packet_name(const int type);
extern const char *dccp_state_name(const int state);
extern void dccp_set_state(struct sock *sk, const int state);
extern void dccp_done(struct sock *sk);
extern void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb);
extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
extern struct sock *dccp_create_openreq_child(struct sock *sk,
const struct request_sock *req,
const struct sk_buff *skb);
extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
extern struct sock *dccp_v4_request_recv_sock(struct sock *sk,
struct sk_buff *skb,
struct request_sock *req,
struct dst_entry *dst);
extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
struct request_sock *req,
struct request_sock **prev);
extern int dccp_child_process(struct sock *parent, struct sock *child,
struct sk_buff *skb);
extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
struct dccp_hdr *dh, unsigned len);
extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
const struct dccp_hdr *dh, const unsigned len);
extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
extern int dccp_destroy_sock(struct sock *sk);
extern void dccp_close(struct sock *sk, long timeout);
extern struct sk_buff *dccp_make_response(struct sock *sk,
struct dst_entry *dst,
struct request_sock *req);
extern int dccp_connect(struct sock *sk);
extern int dccp_disconnect(struct sock *sk, int flags);
extern void dccp_hash(struct sock *sk);
extern void dccp_unhash(struct sock *sk);
extern int dccp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen);
extern int dccp_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, int optlen);
#ifdef CONFIG_COMPAT
extern int compat_dccp_getsockopt(struct sock *sk,
int level, int optname,
char __user *optval, int __user *optlen);
extern int compat_dccp_setsockopt(struct sock *sk,
int level, int optname,
char __user *optval, int optlen);
#endif
extern int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
extern int dccp_sendmsg(struct kiocb *iocb, struct sock *sk,
struct msghdr *msg, size_t size);
extern int dccp_recvmsg(struct kiocb *iocb, struct sock *sk,
struct msghdr *msg, size_t len, int nonblock,
int flags, int *addr_len);
extern void dccp_shutdown(struct sock *sk, int how);
extern int inet_dccp_listen(struct socket *sock, int backlog);
extern unsigned int dccp_poll(struct file *file, struct socket *sock,
poll_table *wait);
extern int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
int addr_len);
extern int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
extern void dccp_send_close(struct sock *sk, const int active);
extern int dccp_invalid_packet(struct sk_buff *skb);
static inline int dccp_bad_service_code(const struct sock *sk,
const __be32 service)
{
const struct dccp_sock *dp = dccp_sk(sk);
if (dp->dccps_service == service)
return 0;
return !dccp_list_has_service(dp->dccps_service_list, service);
}
struct dccp_skb_cb {
__u8 dccpd_type:4;
__u8 dccpd_ccval:4;
__u8 dccpd_reset_code;
__u16 dccpd_opt_len;
__u64 dccpd_seq;
__u64 dccpd_ack_seq;
};
#define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
static inline int dccp_non_data_packet(const struct sk_buff *skb)
{
const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
return type == DCCP_PKT_ACK ||
type == DCCP_PKT_CLOSE ||
type == DCCP_PKT_CLOSEREQ ||
type == DCCP_PKT_RESET ||
type == DCCP_PKT_SYNC ||
type == DCCP_PKT_SYNCACK;
}
static inline int dccp_packet_without_ack(const struct sk_buff *skb)
{
const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
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;
}
static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
{
struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
sizeof(*dh));
dh->dccph_seq2 = 0;
dh->dccph_seq = htons((gss >> 32) & 0xfffff);
dhx->dccph_seq_low = htonl(gss & 0xffffffff);
}
static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
const u64 gsr)
{
dhack->dccph_reserved1 = 0;
dhack->dccph_ack_nr_high = htons(gsr >> 32);
dhack->dccph_ack_nr_low = htonl(gsr & 0xffffffff);
}
static inline void dccp_update_gsr(struct sock *sk, u64 seq)
{
struct dccp_sock *dp = dccp_sk(sk);
const struct dccp_minisock *dmsk = dccp_msk(sk);
dp->dccps_gsr = seq;
dccp_set_seqno(&dp->dccps_swl,
dp->dccps_gsr + 1 - (dmsk->dccpms_sequence_window / 4));
dccp_set_seqno(&dp->dccps_swh,
dp->dccps_gsr + (3 * dmsk->dccpms_sequence_window) / 4);
}
static inline void dccp_update_gss(struct sock *sk, u64 seq)
{
struct dccp_sock *dp = dccp_sk(sk);
dp->dccps_awh = dp->dccps_gss = seq;
dccp_set_seqno(&dp->dccps_awl,
(dp->dccps_gss -
dccp_msk(sk)->dccpms_sequence_window + 1));
}
static inline int dccp_ack_pending(const struct sock *sk)
{
const struct dccp_sock *dp = dccp_sk(sk);
return dp->dccps_timestamp_echo != 0 ||
#ifdef CONFIG_IP_DCCP_ACKVEC
(dccp_msk(sk)->dccpms_send_ack_vector &&
dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
#endif
inet_csk_ack_scheduled(sk);
}
extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
extern int dccp_insert_option_elapsed_time(struct sock *sk,
struct sk_buff *skb,
u32 elapsed_time);
extern int dccp_insert_option_timestamp(struct sock *sk,
struct sk_buff *skb);
extern int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
unsigned char option,
const void *value, unsigned char len);
extern void dccp_timestamp(const struct sock *sk, struct timeval *tv);
static inline suseconds_t timeval_usecs(const struct timeval *tv)
{
return tv->tv_sec * USEC_PER_SEC + tv->tv_usec;
}
static inline suseconds_t timeval_delta(const struct timeval *large,
const struct timeval *small)
{
time_t secs = large->tv_sec - small->tv_sec;
suseconds_t usecs = large->tv_usec - small->tv_usec;
if (usecs < 0) {
secs--;
usecs += USEC_PER_SEC;
}
return secs * USEC_PER_SEC + usecs;
}
static inline void timeval_add_usecs(struct timeval *tv,
const suseconds_t usecs)
{
tv->tv_usec += usecs;
while (tv->tv_usec >= USEC_PER_SEC) {
tv->tv_sec++;
tv->tv_usec -= USEC_PER_SEC;
}
}
static inline void timeval_sub_usecs(struct timeval *tv,
const suseconds_t usecs)
{
tv->tv_usec -= usecs;
while (tv->tv_usec < 0) {
tv->tv_sec--;
tv->tv_usec += USEC_PER_SEC;
}
}
#ifdef CONFIG_SYSCTL
extern int dccp_sysctl_init(void);
extern void dccp_sysctl_exit(void);
#else
static inline int dccp_sysctl_init(void)
{
return 0;
}
static inline void dccp_sysctl_exit(void)
{
}
#endif
#endif /* _DCCP_H */
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