[net-next-2.6.git] / net / dccp / options.c

/*
 *  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 <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
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */
#include <linux/dccp.h>
#include <linux/module.h>
#include <linux/types.h>
#include <asm/unaligned.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>

#include "ackvec.h"
#include "ccid.h"
#include "dccp.h"
#include "feat.h"

u64 dccp_decode_value_var(const u8 *bf, const u8 len)
{
	u64 value = 0;

	if (len >= DCCP_OPTVAL_MAXLEN)
		value += ((u64)*bf++) << 40;
	if (len > 4)
		value += ((u64)*bf++) << 32;
	if (len > 3)
		value += ((u64)*bf++) << 24;
	if (len > 2)
		value += ((u64)*bf++) << 16;
	if (len > 1)
		value += ((u64)*bf++) << 8;
	if (len > 0)
		value += *bf;

	return value;
}

/**
 * dccp_parse_options  -  Parse DCCP options present in @skb
 * @sk: client|server|listening dccp socket (when @dreq != NULL)
 * @dreq: request socket to use during connection setup, or NULL
 */
int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
		       struct sk_buff *skb)
{
	struct dccp_sock *dp = dccp_sk(sk);
	const struct dccp_hdr *dh = dccp_hdr(skb);
	const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
	u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
	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 *uninitialized_var(value);
	u32 elapsed_time;
	__be32 opt_val;
	int rc;
	int mandatory = 0;

	memset(opt_recv, 0, sizeof(*opt_recv));

	opt = len = 0;
	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_nonsensical_length;

			len = *opt_ptr++;
			if (len < 2)
				goto out_nonsensical_length;
			/*
			 * 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_nonsensical_length;
		}

		/*
		 * CCID-Specific Options (from RFC 4340, sec. 10.3):
		 *
		 * 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.
		 *
		 * CCID-specific options are ignored during connection setup, as
		 * negotiation may still be in progress (see RFC 4340, 10.3).
		 * The same applies to Ack Vectors, as these depend on the CCID.
		 *
		 */
		if (dreq != NULL && (opt >= 128 ||
		    opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1))
			goto ignore_option;

		switch (opt) {
		case DCCPO_PADDING:
			break;
		case DCCPO_MANDATORY:
			if (mandatory)
				goto out_invalid_option;
			if (pkt_type != DCCP_PKT_DATA)
				mandatory = 1;
			break;
		case DCCPO_NDP_COUNT:
			if (len > 6)
				goto out_invalid_option;

			opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
			dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),
				      (unsigned long long)opt_recv->dccpor_ndp);
			break;
		case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R:
			if (pkt_type == DCCP_PKT_DATA)      /* RFC 4340, 6 */
				break;
			rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,
						    *value, value + 1, len - 1);
			if (rc)
				goto out_featneg_failed;
			break;
		case DCCPO_ACK_VECTOR_0:
		case DCCPO_ACK_VECTOR_1:
			if (dccp_packet_without_ack(skb))   /* RFC 4340, 11.4 */
				break;
			if (dp->dccps_hc_rx_ackvec != NULL &&
			    dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
				goto out_invalid_option;
			break;
		case DCCPO_TIMESTAMP:
			if (len != 4)
				goto out_invalid_option;
			/*
			 * RFC 4340 13.1: "The precise time corresponding to
			 * Timestamp Value zero is not specified". We use
			 * zero to indicate absence of a meaningful timestamp.
			 */
			opt_val = get_unaligned((__be32 *)value);
			if (unlikely(opt_val == 0)) {
				DCCP_WARN("Timestamp with zero value\n");
				break;
			}

			if (dreq != NULL) {
				dreq->dreq_timestamp_echo = ntohl(opt_val);
				dreq->dreq_timestamp_time = dccp_timestamp();
			} else {
				opt_recv->dccpor_timestamp =
					dp->dccps_timestamp_echo = ntohl(opt_val);
				dp->dccps_timestamp_time = dccp_timestamp();
			}
			dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
				      dccp_role(sk), ntohl(opt_val),
				      (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_val = get_unaligned((__be32 *)value);
			opt_recv->dccpor_timestamp_echo = ntohl(opt_val);

			dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
				      "ackno=%llu", dccp_role(sk),
				      opt_recv->dccpor_timestamp_echo,
				      len + 2,
				      (unsigned long long)
				      DCCP_SKB_CB(skb)->dccpd_ack_seq);

			value += 4;

			if (len == 4) {		/* no elapsed time included */
				dccp_pr_debug_cat("\n");
				break;
			}

			if (len == 6) {		/* 2-byte elapsed time */
				__be16 opt_val2 = get_unaligned((__be16 *)value);
				elapsed_time = ntohs(opt_val2);
			} else {		/* 4-byte elapsed time */
				opt_val = get_unaligned((__be32 *)value);
				elapsed_time = ntohl(opt_val);
			}

			dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);

			/* 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 (dccp_packet_without_ack(skb))   /* RFC 4340, 13.2 */
				break;

			if (len == 2) {
				__be16 opt_val2 = get_unaligned((__be16 *)value);
				elapsed_time = ntohs(opt_val2);
			} else if (len == 4) {
				opt_val = get_unaligned((__be32 *)value);
				elapsed_time = ntohl(opt_val);
			} else {
				goto out_invalid_option;
			}

			if (elapsed_time > opt_recv->dccpor_elapsed_time)
				opt_recv->dccpor_elapsed_time = elapsed_time;

			dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
				      dccp_role(sk), elapsed_time);
			break;
		case 128 ... 191:
			if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
						     pkt_type, opt, value, len))
				goto out_invalid_option;
			break;
		case 192 ... 255:
			if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
						     pkt_type, opt, value, len))
				goto out_invalid_option;
			break;
		default:
			DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
				  "implemented, ignoring", sk, opt, len);
			break;
		}
ignore_option:
		if (opt != DCCPO_MANDATORY)
			mandatory = 0;
	}

	/* mandatory was the last byte in option list -> reset connection */
	if (mandatory)
		goto out_invalid_option;

out_nonsensical_length:
	/* RFC 4340, 5.8: ignore option and all remaining option space */
	return 0;

out_invalid_option:
	DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
	rc = DCCP_RESET_CODE_OPTION_ERROR;
out_featneg_failed:
	DCCP_WARN("DCCP(%p): Option %d (len=%d) error=%u\n", sk, opt, len, rc);
	DCCP_SKB_CB(skb)->dccpd_reset_code = rc;
	DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;
	DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;
	DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;
	return -1;
}

EXPORT_SYMBOL_GPL(dccp_parse_options);

void dccp_encode_value_var(const u64 value, u8 *to, const u8 len)
{
	if (len >= DCCP_OPTVAL_MAXLEN)
		*to++ = (value & 0xFF0000000000ull) >> 40;
	if (len > 4)
		*to++ = (value & 0xFF00000000ull) >> 32;
	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 u8 dccp_ndp_len(const u64 ndp)
{
	if (likely(ndp <= 0xFF))
		return 1;
	return likely(ndp <= USHRT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6);
}

int dccp_insert_option(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)
		return -1;

	DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;

	to    = skb_push(skb, len + 2);
	*to++ = option;
	*to++ = len + 2;

	memcpy(to, value, len);
	return 0;
}

EXPORT_SYMBOL_GPL(dccp_insert_option);

static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
{
	struct dccp_sock *dp = dccp_sk(sk);
	u64 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 -1;

		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);
	}

	return 0;
}

static inline int dccp_elapsed_time_len(const u32 elapsed_time)
{
	return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
}

int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed_time)
{
	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 0;

	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
		return -1;

	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 __be16 var16 = htons((u16)elapsed_time);
		memcpy(to, &var16, 2);
	} else {
		const __be32 var32 = htonl(elapsed_time);
		memcpy(to, &var32, 4);
	}

	return 0;
}

EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);

int dccp_insert_option_timestamp(struct sk_buff *skb)
{
	__be32 now = htonl(dccp_timestamp());
	/* 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 */

	return dccp_insert_option(skb, DCCPO_TIMESTAMP, &now, sizeof(now));
}

EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);

static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
					     struct dccp_request_sock *dreq,
					     struct sk_buff *skb)
{
	__be32 tstamp_echo;
	unsigned char *to;
	u32 elapsed_time, elapsed_time_len, len;

	if (dreq != NULL) {
		elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time;
		tstamp_echo  = htonl(dreq->dreq_timestamp_echo);
		dreq->dreq_timestamp_echo = 0;
	} else {
		elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time;
		tstamp_echo  = htonl(dp->dccps_timestamp_echo);
		dp->dccps_timestamp_echo = 0;
	}

	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)
		return -1;

	DCCP_SKB_CB(skb)->dccpd_opt_len += len;

	to    = skb_push(skb, len);
	*to++ = DCCPO_TIMESTAMP_ECHO;
	*to++ = len;

	memcpy(to, &tstamp_echo, 4);
	to += 4;

	if (elapsed_time_len == 2) {
		const __be16 var16 = htons((u16)elapsed_time);
		memcpy(to, &var16, 2);
	} else if (elapsed_time_len == 4) {
		const __be32 var32 = htonl(elapsed_time);
		memcpy(to, &var32, 4);
	}

	return 0;
}

/**
 * dccp_insert_option_mandatory  -  Mandatory option (5.8.2)
 * Note that since we are using skb_push, this function needs to be called
 * _after_ inserting the option it is supposed to influence (stack order).
 */
int dccp_insert_option_mandatory(struct sk_buff *skb)
{
	if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN)
		return -1;

	DCCP_SKB_CB(skb)->dccpd_opt_len++;
	*skb_push(skb, 1) = DCCPO_MANDATORY;
	return 0;
}

/**
 * dccp_insert_fn_opt  -  Insert single Feature-Negotiation option into @skb
 * @type: %DCCPO_CHANGE_L, %DCCPO_CHANGE_R, %DCCPO_CONFIRM_L, %DCCPO_CONFIRM_R
 * @feat: one out of %dccp_feature_numbers
 * @val: NN value or SP array (preferred element first) to copy
 * @len: true length of @val in bytes (excluding first element repetition)
 * @repeat_first: whether to copy the first element of @val twice
 * The last argument is used to construct Confirm options, where the preferred
 * value and the preference list appear separately (RFC 4340, 6.3.1). Preference
 * lists are kept such that the preferred entry is always first, so we only need
 * to copy twice, and avoid the overhead of cloning into a bigger array.
 */
int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat,
		       u8 *val, u8 len, bool repeat_first)
{
	u8 tot_len, *to;

	/* take the `Feature' field and possible repetition into account */
	if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) {
		DCCP_WARN("length %u for feature %u too large\n", len, feat);
		return -1;
	}

	if (unlikely(val == NULL || len == 0))
		len = repeat_first = 0;
	tot_len = 3 + repeat_first + len;

	if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) {
		DCCP_WARN("packet too small for feature %d option!\n", feat);
		return -1;
	}
	DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len;

	to    = skb_push(skb, tot_len);
	*to++ = type;
	*to++ = tot_len;
	*to++ = feat;

	if (repeat_first)
		*to++ = *val;
	if (len)
		memcpy(to, val, len);
	return 0;
}

/* The length of all options needs to be a multiple of 4 (5.8) */
static void dccp_insert_option_padding(struct sk_buff *skb)
{
	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;
	}
}

int 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_send_ndp_count && dccp_insert_option_ndp(sk, skb))
		return -1;

	if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) {

		/* Feature Negotiation */
		if (dccp_feat_insert_opts(dp, NULL, skb))
			return -1;

		if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) {
			/*
			 * Obtain RTT sample from Request/Response exchange.
			 * This is currently used for TFRC initialisation.
			 */
			if (dccp_insert_option_timestamp(skb))
				return -1;

		} else if (dp->dccps_hc_rx_ackvec != NULL &&
			   dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
			   dccp_insert_option_ackvec(sk, skb)) {
				return -1;
		}
	}

	if (dp->dccps_hc_rx_insert_options) {
		if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
			return -1;
		dp->dccps_hc_rx_insert_options = 0;
	}

	if (dp->dccps_timestamp_echo != 0 &&
	    dccp_insert_option_timestamp_echo(dp, NULL, skb))
		return -1;

	dccp_insert_option_padding(skb);
	return 0;
}

int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
{
	DCCP_SKB_CB(skb)->dccpd_opt_len = 0;

	if (dccp_feat_insert_opts(NULL, dreq, skb))
		return -1;

	/* Obtain RTT sample from Response/Ack exchange (used by TFRC). */
	if (dccp_insert_option_timestamp(skb))
		return -1;

	if (dreq->dreq_timestamp_echo != 0 &&
	    dccp_insert_option_timestamp_echo(NULL, dreq, skb))
		return -1;

	dccp_insert_option_padding(skb);
	return 0;
}
Commit	Line	Data
7c657876 ACM	1	/*
	2	* net/dccp/options.c
	3	*
	4	* An implementation of the DCCP protocol
1bc09869 IM	5	* Copyright (c) 2005 Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
1bc09869 IM	6	* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
e6bccd35	7	* Copyright (c) 2005 Ian McDonald <ian.mcdonald@jandi.co.nz>
7c657876 ACM	8	*
	9	* This program is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU General Public License
	11	* as published by the Free Software Foundation; either version
	12	* 2 of the License, or (at your option) any later version.
	13	*/
7c657876 ACM	14	#include <linux/dccp.h>
	15	#include <linux/module.h>
	16	#include <linux/types.h>
76fd1e87	17	#include <asm/unaligned.h>
7c657876 ACM	18	#include <linux/kernel.h>
	19	#include <linux/skbuff.h>
	20
ae31c339	21	#include "ackvec.h"
7c657876 ACM	22	#include "ccid.h"
7c657876 ACM	23	#include "dccp.h"
afe00251	24	#include "feat.h"
7c657876	25
02fa460e	26	u64 dccp_decode_value_var(const u8 *bf, const u8 len)
7c657876	27	{
02fa460e	28	u64 value = 0;
7c657876	29
02fa460e GR	30	if (len >= DCCP_OPTVAL_MAXLEN)
	31	value += ((u64)*bf++) << 40;
	32	if (len > 4)
	33	value += ((u64)*bf++) << 32;
7c657876	34	if (len > 3)
02fa460e	35	value += ((u64)*bf++) << 24;
7c657876	36	if (len > 2)
02fa460e	37	value += ((u64)*bf++) << 16;
7c657876	38	if (len > 1)
02fa460e	39	value += ((u64)*bf++) << 8;
7c657876 ACM	40	if (len > 0)
	41	value += *bf;
	42
	43	return value;
	44	}
	45
8b819412 GR	46	/**
	47	* dccp_parse_options - Parse DCCP options present in @skb
	48	* @sk: client\|server\|listening dccp socket (when @dreq != NULL)
	49	* @dreq: request socket to use during connection setup, or NULL
	50	*/
	51	int dccp_parse_options(struct sock sk, struct dccp_request_sock dreq,
	52	struct sk_buff *skb)
7c657876 ACM	53	{
7c657876 ACM	54	struct dccp_sock *dp = dccp_sk(sk);
7c657876 ACM	55	const struct dccp_hdr *dh = dccp_hdr(skb);
7c657876 ACM	56	const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
410e27a4	57	u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
7c657876 ACM	58	unsigned char options = (unsigned char )dh + dccp_hdr_len(skb);
7c657876 ACM	59	unsigned char *opt_ptr = options;
7690af3f ACM	60	const unsigned char opt_end = (unsigned char )dh +
7690af3f ACM	61	(dh->dccph_doff * 4);
7c657876 ACM	62	struct dccp_options_received *opt_recv = &dp->dccps_options_received;
7c657876 ACM	63	unsigned char opt, len;
3ed7cc0f	64	unsigned char *uninitialized_var(value);
1c14ac0a	65	u32 elapsed_time;
76fd1e87	66	__be32 opt_val;
afe00251 AB	67	int rc;
afe00251 AB	68	int mandatory = 0;
7c657876 ACM	69
	70	memset(opt_recv, 0, sizeof(*opt_recv));
	71
fb950496	72	opt = len = 0;
7c657876 ACM	73	while (opt_ptr != opt_end) {
	74	opt = *opt_ptr++;
	75	len = 0;
	76	value = NULL;
	77
	78	/* Check if this isn't a single byte option */
	79	if (opt > DCCPO_MAX_RESERVED) {
	80	if (opt_ptr == opt_end)
faf61c33	81	goto out_nonsensical_length;
7c657876 ACM	82
7c657876 ACM	83	len = *opt_ptr++;
faf61c33 GR	84	if (len < 2)
faf61c33 GR	85	goto out_nonsensical_length;
7c657876 ACM	86	/*
	87	* Remove the type and len fields, leaving
	88	* just the value size
	89	*/
	90	len -= 2;
	91	value = opt_ptr;
	92	opt_ptr += len;
	93
	94	if (opt_ptr > opt_end)
faf61c33	95	goto out_nonsensical_length;
7c657876 ACM	96	}
7c657876 ACM	97
8b819412	98	/*
410e27a4 GR	99	* CCID-Specific Options (from RFC 4340, sec. 10.3):
	100	*
	101	* Option numbers 128 through 191 are for options sent from the
	102	* HC-Sender to the HC-Receiver; option numbers 192 through 255
	103	* are for options sent from the HC-Receiver to the HC-Sender.
	104	*
8b819412 GR	105	* CCID-specific options are ignored during connection setup, as
8b819412 GR	106	* negotiation may still be in progress (see RFC 4340, 10.3).
65907a43	107	* The same applies to Ack Vectors, as these depend on the CCID.
410e27a4	108	*
8b819412	109	*/
410e27a4	110	if (dreq != NULL && (opt >= 128 \|\|
65907a43	111	opt == DCCPO_ACK_VECTOR_0 \|\| opt == DCCPO_ACK_VECTOR_1))
8b819412 GR	112	goto ignore_option;
8b819412 GR	113
7c657876 ACM	114	switch (opt) {
	115	case DCCPO_PADDING:
	116	break;
afe00251 AB	117	case DCCPO_MANDATORY:
	118	if (mandatory)
	119	goto out_invalid_option;
6df9424a ACM	120	if (pkt_type != DCCP_PKT_DATA)
6df9424a ACM	121	mandatory = 1;
afe00251	122	break;
7c657876	123	case DCCPO_NDP_COUNT:
5b5d0e70	124	if (len > 6)
7c657876 ACM	125	goto out_invalid_option;
	126
	127	opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
5b5d0e70 GR	128	dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),
5b5d0e70 GR	129	(unsigned long long)opt_recv->dccpor_ndp);
7c657876	130	break;
b1ad0042 GR	131	case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R:
b1ad0042 GR	132	if (pkt_type == DCCP_PKT_DATA) /* RFC 4340, 6 */
cf86314c	133	break;
e77b8363 GR	134	rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,
	135	*value, value + 1, len - 1);
	136	if (rc)
	137	goto out_featneg_failed;
410e27a4	138	break;
410e27a4 GR	139	case DCCPO_ACK_VECTOR_0:
	140	case DCCPO_ACK_VECTOR_1:
	141	if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */
	142	break;
6fdd34d4	143	if (dp->dccps_hc_rx_ackvec != NULL &&
410e27a4 GR	144	dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
410e27a4 GR	145	goto out_invalid_option;
afe00251	146	break;
7c657876 ACM	147	case DCCPO_TIMESTAMP:
	148	if (len != 4)
	149	goto out_invalid_option;
b4d4f7c7 GR	150	/*
	151	* RFC 4340 13.1: "The precise time corresponding to
	152	* Timestamp Value zero is not specified". We use
	153	* zero to indicate absence of a meaningful timestamp.
	154	*/
76fd1e87	155	opt_val = get_unaligned((__be32 *)value);
b4d4f7c7 GR	156	if (unlikely(opt_val == 0)) {
	157	DCCP_WARN("Timestamp with zero value\n");
	158	break;
	159	}
7c657876	160
b4d4f7c7 GR	161	if (dreq != NULL) {
	162	dreq->dreq_timestamp_echo = ntohl(opt_val);
	163	dreq->dreq_timestamp_time = dccp_timestamp();
	164	} else {
	165	opt_recv->dccpor_timestamp =
	166	dp->dccps_timestamp_echo = ntohl(opt_val);
	167	dp->dccps_timestamp_time = dccp_timestamp();
	168	}
09dbc389	169	dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
b4d4f7c7	170	dccp_role(sk), ntohl(opt_val),
f6ccf554	171	(unsigned long long)
7c657876 ACM	172	DCCP_SKB_CB(skb)->dccpd_ack_seq);
	173	break;
	174	case DCCPO_TIMESTAMP_ECHO:
1bc09869	175	if (len != 4 && len != 6 && len != 8)
7c657876 ACM	176	goto out_invalid_option;
7c657876 ACM	177
76fd1e87 GR	178	opt_val = get_unaligned((__be32 *)value);
76fd1e87 GR	179	opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
7c657876	180
09dbc389	181	dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
f73f7097	182	"ackno=%llu", dccp_role(sk),
7690af3f	183	opt_recv->dccpor_timestamp_echo,
f6ccf554 DM	184	len + 2,
f6ccf554 DM	185	(unsigned long long)
1bc09869 IM	186	DCCP_SKB_CB(skb)->dccpd_ack_seq);
1bc09869 IM	187
76fd1e87	188	value += 4;
1bc09869	189
76fd1e87	190	if (len == 4) { /* no elapsed time included */
f73f7097	191	dccp_pr_debug_cat("\n");
1c14ac0a	192	break;
f73f7097	193	}
1c14ac0a	194
76fd1e87 GR	195	if (len == 6) { /* 2-byte elapsed time */
	196	__be16 opt_val2 = get_unaligned((__be16 *)value);
	197	elapsed_time = ntohs(opt_val2);
	198	} else { /* 4-byte elapsed time */
	199	opt_val = get_unaligned((__be32 *)value);
	200	elapsed_time = ntohl(opt_val);
	201	}
1c14ac0a	202
dcad856f	203	dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
f73f7097	204
1c14ac0a ACM	205	/* Give precedence to the biggest ELAPSED_TIME */
	206	if (elapsed_time > opt_recv->dccpor_elapsed_time)
	207	opt_recv->dccpor_elapsed_time = elapsed_time;
7c657876 ACM	208	break;
7c657876 ACM	209	case DCCPO_ELAPSED_TIME:
c86ab2b6 GR	210	if (dccp_packet_without_ack(skb)) /* RFC 4340, 13.2 */
c86ab2b6 GR	211	break;
1bc09869	212
76fd1e87 GR	213	if (len == 2) {
	214	__be16 opt_val2 = get_unaligned((__be16 *)value);
	215	elapsed_time = ntohs(opt_val2);
c86ab2b6	216	} else if (len == 4) {
76fd1e87 GR	217	opt_val = get_unaligned((__be32 *)value);
76fd1e87 GR	218	elapsed_time = ntohl(opt_val);
c86ab2b6 GR	219	} else {
c86ab2b6 GR	220	goto out_invalid_option;
76fd1e87	221	}
1c14ac0a ACM	222
	223	if (elapsed_time > opt_recv->dccpor_elapsed_time)
	224	opt_recv->dccpor_elapsed_time = elapsed_time;
1bc09869	225
09dbc389 GR	226	dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
09dbc389 GR	227	dccp_role(sk), elapsed_time);
7c657876	228	break;
4874c131	229	case 128 ... 191:
7690af3f	230	if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
4874c131	231	pkt_type, opt, value, len))
7c657876	232	goto out_invalid_option;
7c657876	233	break;
4874c131	234	case 192 ... 255:
7690af3f	235	if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
4874c131	236	pkt_type, opt, value, len))
7c657876	237	goto out_invalid_option;
7c657876 ACM	238	break;
7c657876 ACM	239	default:
59348b19 GR	240	DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
59348b19 GR	241	"implemented, ignoring", sk, opt, len);
7c657876	242	break;
c9eaf173	243	}
8b819412	244	ignore_option:
afe00251 AB	245	if (opt != DCCPO_MANDATORY)
afe00251 AB	246	mandatory = 0;
7c657876 ACM	247	}
7c657876 ACM	248
6df9424a ACM	249	/* mandatory was the last byte in option list -> reset connection */
	250	if (mandatory)
	251	goto out_invalid_option;
	252
faf61c33 GR	253	out_nonsensical_length:
faf61c33 GR	254	/* RFC 4340, 5.8: ignore option and all remaining option space */
7c657876 ACM	255	return 0;
	256
	257	out_invalid_option:
	258	DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
e77b8363 GR	259	rc = DCCP_RESET_CODE_OPTION_ERROR;
	260	out_featneg_failed:
	261	DCCP_WARN("DCCP(%p): Option %d (len=%d) error=%u\n", sk, opt, len, rc);
	262	DCCP_SKB_CB(skb)->dccpd_reset_code = rc;
eac7726b GR	263	DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;
	264	DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;
	265	DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;
7c657876 ACM	266	return -1;
	267	}
	268
b61fafc4 ACM	269	EXPORT_SYMBOL_GPL(dccp_parse_options);
b61fafc4 ACM	270
02fa460e	271	void dccp_encode_value_var(const u64 value, u8 *to, const u8 len)
7c657876	272	{
02fa460e GR	273	if (len >= DCCP_OPTVAL_MAXLEN)
	274	*to++ = (value & 0xFF0000000000ull) >> 40;
	275	if (len > 4)
	276	*to++ = (value & 0xFF00000000ull) >> 32;
7c657876 ACM	277	if (len > 3)
	278	*to++ = (value & 0xFF000000) >> 24;
	279	if (len > 2)
	280	*to++ = (value & 0xFF0000) >> 16;
	281	if (len > 1)
	282	*to++ = (value & 0xFF00) >> 8;
	283	if (len > 0)
	284	*to++ = (value & 0xFF);
	285	}
	286
5b5d0e70	287	static inline u8 dccp_ndp_len(const u64 ndp)
7c657876	288	{
5b5d0e70 GR	289	if (likely(ndp <= 0xFF))
5b5d0e70 GR	290	return 1;
4be929be	291	return likely(ndp <= USHRT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6);
7c657876 ACM	292	}
7c657876 ACM	293
a7d13fbf GR	294	int dccp_insert_option(struct sk_buff *skb, const unsigned char option,
a7d13fbf GR	295	const void *value, const unsigned char len)
7c657876 ACM	296	{
	297	unsigned char *to;
	298
2d0817d1 ACM	299	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
2d0817d1 ACM	300	return -1;
7c657876 ACM	301
	302	DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
	303
	304	to = skb_push(skb, len + 2);
	305	*to++ = option;
	306	*to++ = len + 2;
	307
	308	memcpy(to, value, len);
2d0817d1	309	return 0;
7c657876 ACM	310	}
	311
	312	EXPORT_SYMBOL_GPL(dccp_insert_option);
	313
2d0817d1	314	static int dccp_insert_option_ndp(struct sock sk, struct sk_buff skb)
7c657876 ACM	315	{
7c657876 ACM	316	struct dccp_sock *dp = dccp_sk(sk);
5b5d0e70	317	u64 ndp = dp->dccps_ndp_count;
7c657876 ACM	318
	319	if (dccp_non_data_packet(skb))
	320	++dp->dccps_ndp_count;
	321	else
	322	dp->dccps_ndp_count = 0;
	323
	324	if (ndp > 0) {
	325	unsigned char *ptr;
	326	const int ndp_len = dccp_ndp_len(ndp);
	327	const int len = ndp_len + 2;
	328
	329	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
2d0817d1	330	return -1;
7c657876 ACM	331
	332	DCCP_SKB_CB(skb)->dccpd_opt_len += len;
	333
	334	ptr = skb_push(skb, len);
	335	*ptr++ = DCCPO_NDP_COUNT;
	336	*ptr++ = len;
	337	dccp_encode_value_var(ndp, ptr, ndp_len);
	338	}
2d0817d1 ACM	339
2d0817d1 ACM	340	return 0;
7c657876 ACM	341	}
	342
	343	static inline int dccp_elapsed_time_len(const u32 elapsed_time)
	344	{
b1c9fe7b	345	return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
7c657876 ACM	346	}
7c657876 ACM	347
a7d13fbf	348	int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed_time)
7c657876	349	{
7c657876 ACM	350	const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
	351	const int len = 2 + elapsed_time_len;
	352	unsigned char *to;
	353
1bc09869	354	if (elapsed_time_len == 0)
2d0817d1	355	return 0;
7c657876	356
2d0817d1 ACM	357	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
2d0817d1 ACM	358	return -1;
7c657876 ACM	359
	360	DCCP_SKB_CB(skb)->dccpd_opt_len += len;
	361
	362	to = skb_push(skb, len);
	363	*to++ = DCCPO_ELAPSED_TIME;
	364	*to++ = len;
	365
1bc09869	366	if (elapsed_time_len == 2) {
60fe62e7	367	const __be16 var16 = htons((u16)elapsed_time);
1bc09869 IM	368	memcpy(to, &var16, 2);
1bc09869 IM	369	} else {
60fe62e7	370	const __be32 var32 = htonl(elapsed_time);
1bc09869 IM	371	memcpy(to, &var32, 4);
1bc09869 IM	372	}
7c657876	373
2d0817d1	374	return 0;
7c657876 ACM	375	}
7c657876 ACM	376
d4b81ff7	377	EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
7c657876	378
a7d13fbf	379	int dccp_insert_option_timestamp(struct sk_buff *skb)
7c657876	380	{
4c70f383	381	__be32 now = htonl(dccp_timestamp());
1bc09869 IM	382	/* yes this will overflow but that is the point as we want a
	383	* 10 usec 32 bit timer which mean it wraps every 11.9 hours */
	384
a7d13fbf	385	return dccp_insert_option(skb, DCCPO_TIMESTAMP, &now, sizeof(now));
7c657876 ACM	386	}
7c657876 ACM	387
d4b81ff7 ACM	388	EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
d4b81ff7 ACM	389
b4d4f7c7 GR	390	static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
b4d4f7c7 GR	391	struct dccp_request_sock *dreq,
2d0817d1	392	struct sk_buff *skb)
7c657876	393	{
60fe62e7	394	__be32 tstamp_echo;
7c657876	395	unsigned char *to;
b4d4f7c7 GR	396	u32 elapsed_time, elapsed_time_len, len;
	397
	398	if (dreq != NULL) {
	399	elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time;
	400	tstamp_echo = htonl(dreq->dreq_timestamp_echo);
	401	dreq->dreq_timestamp_echo = 0;
	402	} else {
	403	elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time;
	404	tstamp_echo = htonl(dp->dccps_timestamp_echo);
	405	dp->dccps_timestamp_echo = 0;
	406	}
	407
b0e56780 ACM	408	elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
	409	len = 6 + elapsed_time_len;
	410
2d0817d1 ACM	411	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
2d0817d1 ACM	412	return -1;
7c657876 ACM	413
	414	DCCP_SKB_CB(skb)->dccpd_opt_len += len;
	415
	416	to = skb_push(skb, len);
	417	*to++ = DCCPO_TIMESTAMP_ECHO;
	418	*to++ = len;
	419
7c657876 ACM	420	memcpy(to, &tstamp_echo, 4);
7c657876 ACM	421	to += 4;
afe00251	422
1bc09869	423	if (elapsed_time_len == 2) {
60fe62e7	424	const __be16 var16 = htons((u16)elapsed_time);
1bc09869 IM	425	memcpy(to, &var16, 2);
1bc09869 IM	426	} else if (elapsed_time_len == 4) {
60fe62e7	427	const __be32 var32 = htonl(elapsed_time);
1bc09869 IM	428	memcpy(to, &var32, 4);
1bc09869 IM	429	}
7c657876	430
2d0817d1	431	return 0;
7c657876 ACM	432	}
7c657876 ACM	433
d3710566 GR	434	/**
	435	* dccp_insert_option_mandatory - Mandatory option (5.8.2)
	436	* Note that since we are using skb_push, this function needs to be called
	437	* _after_ inserting the option it is supposed to influence (stack order).
	438	*/
	439	int dccp_insert_option_mandatory(struct sk_buff *skb)
	440	{
	441	if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN)
	442	return -1;
	443
	444	DCCP_SKB_CB(skb)->dccpd_opt_len++;
	445	*skb_push(skb, 1) = DCCPO_MANDATORY;
	446	return 0;
	447	}
	448
8c862c23 GR	449	/**
	450	* dccp_insert_fn_opt - Insert single Feature-Negotiation option into @skb
	451	* @type: %DCCPO_CHANGE_L, %DCCPO_CHANGE_R, %DCCPO_CONFIRM_L, %DCCPO_CONFIRM_R
	452	* @feat: one out of %dccp_feature_numbers
	453	* @val: NN value or SP array (preferred element first) to copy
	454	* @len: true length of @val in bytes (excluding first element repetition)
	455	* @repeat_first: whether to copy the first element of @val twice
	456	* The last argument is used to construct Confirm options, where the preferred
	457	* value and the preference list appear separately (RFC 4340, 6.3.1). Preference
	458	* lists are kept such that the preferred entry is always first, so we only need
	459	* to copy twice, and avoid the overhead of cloning into a bigger array.
	460	*/
	461	int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat,
	462	u8 *val, u8 len, bool repeat_first)
4829007c	463	{
8c862c23	464	u8 tot_len, *to;
4829007c	465
8c862c23 GR	466	/* take the `Feature' field and possible repetition into account */
	467	if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) {
	468	DCCP_WARN("length %u for feature %u too large\n", len, feat);
4829007c	469	return -1;
c2f42077	470	}
4829007c	471
8c862c23 GR	472	if (unlikely(val == NULL \|\| len == 0))
	473	len = repeat_first = 0;
	474	tot_len = 3 + repeat_first + len;
	475
	476	if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) {
	477	DCCP_WARN("packet too small for feature %d option!\n", feat);
	478	return -1;
	479	}
	480	DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len;
4829007c	481
8c862c23	482	to = skb_push(skb, tot_len);
410e27a4	483	*to++ = type;
8c862c23	484	*to++ = tot_len;
410e27a4	485	*to++ = feat;
4829007c	486
8c862c23 GR	487	if (repeat_first)
8c862c23 GR	488	to++ = val;
410e27a4 GR	489	if (len)
410e27a4 GR	490	memcpy(to, val, len);
d0440ee6 GR	491	return 0;
	492	}
	493
af3b867e GR	494	/* The length of all options needs to be a multiple of 4 (5.8) */
	495	static void dccp_insert_option_padding(struct sk_buff *skb)
	496	{
	497	int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
	498
	499	if (padding != 0) {
	500	padding = 4 - padding;
	501	memset(skb_push(skb, padding), 0, padding);
	502	DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
	503	}
	504	}
	505
2d0817d1	506	int dccp_insert_options(struct sock sk, struct sk_buff skb)
7c657876 ACM	507	{
	508	struct dccp_sock *dp = dccp_sk(sk);
	509
	510	DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
	511
4098dce5	512	if (dp->dccps_send_ndp_count && dccp_insert_option_ndp(sk, skb))
2d0817d1	513	return -1;
7c657876	514
8b7b6c75 GR	515	if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) {
	516
	517	/* Feature Negotiation */
	518	if (dccp_feat_insert_opts(dp, NULL, skb))
2d0817d1	519	return -1;
8b7b6c75 GR	520
	521	if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) {
	522	/*
	523	* Obtain RTT sample from Request/Response exchange.
59b80802	524	* This is currently used for TFRC initialisation.
8b7b6c75	525	*/
a7d13fbf	526	if (dccp_insert_option_timestamp(skb))
8b7b6c75 GR	527	return -1;
8b7b6c75 GR	528
6fdd34d4	529	} else if (dp->dccps_hc_rx_ackvec != NULL &&
8b7b6c75 GR	530	dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
	531	dccp_insert_option_ackvec(sk, skb)) {
	532	return -1;
	533	}
7c657876 ACM	534	}
7c657876 ACM	535
507d37cf	536	if (dp->dccps_hc_rx_insert_options) {
2d0817d1 ACM	537	if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
2d0817d1 ACM	538	return -1;
507d37cf ACM	539	dp->dccps_hc_rx_insert_options = 0;
507d37cf ACM	540	}
7c657876	541
b4d4f7c7 GR	542	if (dp->dccps_timestamp_echo != 0 &&
	543	dccp_insert_option_timestamp_echo(dp, NULL, skb))
	544	return -1;
	545
af3b867e GR	546	dccp_insert_option_padding(skb);
	547	return 0;
	548	}
7c657876	549
af3b867e GR	550	int dccp_insert_options_rsk(struct dccp_request_sock dreq, struct sk_buff skb)
	551	{
	552	DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
7c657876	553
8b7b6c75 GR	554	if (dccp_feat_insert_opts(NULL, dreq, skb))
	555	return -1;
	556
59b80802 GR	557	/* Obtain RTT sample from Response/Ack exchange (used by TFRC). */
	558	if (dccp_insert_option_timestamp(skb))
	559	return -1;
	560
af3b867e GR	561	if (dreq->dreq_timestamp_echo != 0 &&
	562	dccp_insert_option_timestamp_echo(NULL, dreq, skb))
	563	return -1;
2d0817d1	564
af3b867e	565	dccp_insert_option_padding(skb);
2d0817d1	566	return 0;
7c657876	567	}