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linux/net/dccp/options.c

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/*
* net/dccp/options.c
*
* An implementation of the DCCP protocol
* Copyright (c) 2005 Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
* Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
*
* 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/config.h>
#include <linux/dccp.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include "ackvec.h"
#include "ccid.h"
#include "dccp.h"
/* stores the default values for new connection. may be changed with sysctl */
static const struct dccp_options dccpo_default_values = {
.dccpo_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW,
.dccpo_rx_ccid = DCCPF_INITIAL_CCID,
.dccpo_tx_ccid = DCCPF_INITIAL_CCID,
.dccpo_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR,
.dccpo_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT,
};
void dccp_options_init(struct dccp_options *dccpo)
{
memcpy(dccpo, &dccpo_default_values, sizeof(*dccpo));
}
static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
{
u32 value = 0;
if (len > 3)
value += *bf++ << 24;
if (len > 2)
value += *bf++ << 16;
if (len > 1)
value += *bf++ << 8;
if (len > 0)
value += *bf;
return value;
}
int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
{
struct dccp_sock *dp = dccp_sk(sk);
#ifdef CONFIG_IP_DCCP_DEBUG
const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
"CLIENT rx opt: " : "server rx opt: ";
#endif
const struct dccp_hdr *dh = dccp_hdr(skb);
const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
unsigned char *opt_ptr = options;
const unsigned char *opt_end = (unsigned char *)dh +
(dh->dccph_doff * 4);
struct dccp_options_received *opt_recv = &dp->dccps_options_received;
unsigned char opt, len;
unsigned char *value;
u32 elapsed_time;
memset(opt_recv, 0, sizeof(*opt_recv));
while (opt_ptr != opt_end) {
opt = *opt_ptr++;
len = 0;
value = NULL;
/* Check if this isn't a single byte option */
if (opt > DCCPO_MAX_RESERVED) {
if (opt_ptr == opt_end)
goto out_invalid_option;
len = *opt_ptr++;
if (len < 3)
goto out_invalid_option;
/*
* Remove the type and len fields, leaving
* just the value size
*/
len -= 2;
value = opt_ptr;
opt_ptr += len;
if (opt_ptr > opt_end)
goto out_invalid_option;
}
switch (opt) {
case DCCPO_PADDING:
break;
case DCCPO_NDP_COUNT:
if (len > 3)
goto out_invalid_option;
opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
dccp_pr_debug("%sNDP count=%d\n", debug_prefix,
opt_recv->dccpor_ndp);
break;
case DCCPO_ACK_VECTOR_0:
case DCCPO_ACK_VECTOR_1:
if (pkt_type == DCCP_PKT_DATA)
continue;
if (dp->dccps_options.dccpo_send_ack_vector &&
dccp_ackvec_parse(sk, skb, opt, value, len))
goto out_invalid_option;
break;
case DCCPO_TIMESTAMP:
if (len != 4)
goto out_invalid_option;
opt_recv->dccpor_timestamp = ntohl(*(u32 *)value);
dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
dccp_timestamp(sk, &dp->dccps_timestamp_time);
dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n",
debug_prefix, opt_recv->dccpor_timestamp,
(unsigned long long)
DCCP_SKB_CB(skb)->dccpd_ack_seq);
break;
case DCCPO_TIMESTAMP_ECHO:
if (len != 4 && len != 6 && len != 8)
goto out_invalid_option;
opt_recv->dccpor_timestamp_echo = ntohl(*(u32 *)value);
dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, ",
debug_prefix,
opt_recv->dccpor_timestamp_echo,
len + 2,
(unsigned long long)
DCCP_SKB_CB(skb)->dccpd_ack_seq);
if (len == 4)
break;
if (len == 6)
elapsed_time = ntohs(*(u16 *)(value + 4));
else
elapsed_time = ntohl(*(u32 *)(value + 4));
/* Give precedence to the biggest ELAPSED_TIME */
if (elapsed_time > opt_recv->dccpor_elapsed_time)
opt_recv->dccpor_elapsed_time = elapsed_time;
break;
case DCCPO_ELAPSED_TIME:
if (len != 2 && len != 4)
goto out_invalid_option;
if (pkt_type == DCCP_PKT_DATA)
continue;
if (len == 2)
elapsed_time = ntohs(*(u16 *)value);
else
elapsed_time = ntohl(*(u32 *)value);
if (elapsed_time > opt_recv->dccpor_elapsed_time)
opt_recv->dccpor_elapsed_time = elapsed_time;
dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix,
elapsed_time);
break;
/*
* From draft-ietf-dccp-spec-11.txt:
*
* Option numbers 128 through 191 are for
* options sent from the HC-Sender to the
* HC-Receiver; option numbers 192 through 255
* are for options sent from the HC-Receiver to
* the HC-Sender.
*/
case 128 ... 191: {
const u16 idx = value - options;
if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
opt, len, idx,
value) != 0)
goto out_invalid_option;
}
break;
case 192 ... 255: {
const u16 idx = value - options;
if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
opt, len, idx,
value) != 0)
goto out_invalid_option;
}
break;
default:
pr_info("DCCP(%p): option %d(len=%d) not "
"implemented, ignoring\n",
sk, opt, len);
break;
}
}
return 0;
out_invalid_option:
DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
pr_info("DCCP(%p): invalid option %d, len=%d\n", sk, opt, len);
return -1;
}
static void dccp_encode_value_var(const u32 value, unsigned char *to,
const unsigned int len)
{
if (len > 3)
*to++ = (value & 0xFF000000) >> 24;
if (len > 2)
*to++ = (value & 0xFF0000) >> 16;
if (len > 1)
*to++ = (value & 0xFF00) >> 8;
if (len > 0)
*to++ = (value & 0xFF);
}
static inline int dccp_ndp_len(const int ndp)
{
return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
}
void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
const unsigned char option,
const void *value, const unsigned char len)
{
unsigned char *to;
if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) {
LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
"%d option!\n", option);
return;
}
DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
to = skb_push(skb, len + 2);
*to++ = option;
*to++ = len + 2;
memcpy(to, value, len);
}
EXPORT_SYMBOL_GPL(dccp_insert_option);
static void dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
{
struct dccp_sock *dp = dccp_sk(sk);
int ndp = dp->dccps_ndp_count;
if (dccp_non_data_packet(skb))
++dp->dccps_ndp_count;
else
dp->dccps_ndp_count = 0;
if (ndp > 0) {
unsigned char *ptr;
const int ndp_len = dccp_ndp_len(ndp);
const int len = ndp_len + 2;
if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
return;
DCCP_SKB_CB(skb)->dccpd_opt_len += len;
ptr = skb_push(skb, len);
*ptr++ = DCCPO_NDP_COUNT;
*ptr++ = len;
dccp_encode_value_var(ndp, ptr, ndp_len);
}
}
static inline int dccp_elapsed_time_len(const u32 elapsed_time)
{
return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
}
void dccp_insert_option_elapsed_time(struct sock *sk,
struct sk_buff *skb,
u32 elapsed_time)
{
#ifdef CONFIG_IP_DCCP_DEBUG
struct dccp_sock *dp = dccp_sk(sk);
const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
"CLIENT TX opt: " : "server TX opt: ";
#endif
const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
const int len = 2 + elapsed_time_len;
unsigned char *to;
if (elapsed_time_len == 0)
return;
if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
"insert elapsed time!\n");
return;
}
DCCP_SKB_CB(skb)->dccpd_opt_len += len;
to = skb_push(skb, len);
*to++ = DCCPO_ELAPSED_TIME;
*to++ = len;
if (elapsed_time_len == 2) {
const u16 var16 = htons((u16)elapsed_time);
memcpy(to, &var16, 2);
} else {
const u32 var32 = htonl(elapsed_time);
memcpy(to, &var32, 4);
}
dccp_pr_debug("%sELAPSED_TIME=%u, len=%d, seqno=%llu\n",
debug_prefix, elapsed_time,
len,
(unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
}
EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
void dccp_timestamp(const struct sock *sk, struct timeval *tv)
{
const struct dccp_sock *dp = dccp_sk(sk);
do_gettimeofday(tv);
tv->tv_sec -= dp->dccps_epoch.tv_sec;
tv->tv_usec -= dp->dccps_epoch.tv_usec;
while (tv->tv_usec < 0) {
tv->tv_sec--;
tv->tv_usec += USEC_PER_SEC;
}
}
EXPORT_SYMBOL_GPL(dccp_timestamp);
void dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
{
struct timeval tv;
u32 now;
dccp_timestamp(sk, &tv);
now = timeval_usecs(&tv) / 10;
/* yes this will overflow but that is the point as we want a
* 10 usec 32 bit timer which mean it wraps every 11.9 hours */
now = htonl(now);
dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
}
EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
static void dccp_insert_option_timestamp_echo(struct sock *sk,
struct sk_buff *skb)
{
struct dccp_sock *dp = dccp_sk(sk);
#ifdef CONFIG_IP_DCCP_DEBUG
const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
"CLIENT TX opt: " : "server TX opt: ";
#endif
struct timeval now;
u32 tstamp_echo;
u32 elapsed_time;
int len, elapsed_time_len;
unsigned char *to;
dccp_timestamp(sk, &now);
elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10;
elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
len = 6 + elapsed_time_len;
if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
"timestamp echo!\n");
return;
}
DCCP_SKB_CB(skb)->dccpd_opt_len += len;
to = skb_push(skb, len);
*to++ = DCCPO_TIMESTAMP_ECHO;
*to++ = len;
tstamp_echo = htonl(dp->dccps_timestamp_echo);
memcpy(to, &tstamp_echo, 4);
to += 4;
if (elapsed_time_len == 2) {
const u16 var16 = htons((u16)elapsed_time);
memcpy(to, &var16, 2);
} else if (elapsed_time_len == 4) {
const u32 var32 = htonl(elapsed_time);
memcpy(to, &var32, 4);
}
dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, seqno=%llu\n",
debug_prefix, dp->dccps_timestamp_echo,
len,
(unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
dp->dccps_timestamp_echo = 0;
dp->dccps_timestamp_time.tv_sec = 0;
dp->dccps_timestamp_time.tv_usec = 0;
}
void dccp_insert_options(struct sock *sk, struct sk_buff *skb)
{
struct dccp_sock *dp = dccp_sk(sk);
DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
if (dp->dccps_options.dccpo_send_ndp_count)
dccp_insert_option_ndp(sk, skb);
if (!dccp_packet_without_ack(skb)) {
if (dp->dccps_options.dccpo_send_ack_vector &&
dccp_ackvec_pending(dp->dccps_hc_rx_ackvec))
dccp_insert_option_ackvec(sk, skb);
if (dp->dccps_timestamp_echo != 0)
dccp_insert_option_timestamp_echo(sk, skb);
}
if (dp->dccps_hc_rx_insert_options) {
ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb);
dp->dccps_hc_rx_insert_options = 0;
}
if (dp->dccps_hc_tx_insert_options) {
ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb);
dp->dccps_hc_tx_insert_options = 0;
}
/* XXX: insert other options when appropriate */
if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
/* The length of all options has to be a multiple of 4 */
int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
if (padding != 0) {
padding = 4 - padding;
memset(skb_push(skb, padding), 0, padding);
DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
}
}
}
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