Commit 7d870936 authored by Gerrit Renker's avatar Gerrit Renker
Browse files

dccp ccid-2: Separate internals of Ack Vectors from option-parsing code 



This patch
 * separates Ack Vector housekeeping code from option-insertion code;
 * shifts option-specific code from ackvec.c into options.c;
 * introduces a dedicated routine to take care of the Ack Vector records;
 * simplifies the dccp_ackvec_insert_avr() routine: the BUG_ON was redundant,
   since the list is automatically arranged in descending order of ack_seqno.

Signed-off-by: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
parent f17a37c9

net/dccp/ackvec.c

+18 −82
Original line number Diff line number Diff line
@@ -52,99 +52,35 @@ void dccp_ackvec_free(struct dccp_ackvec *av) 
	}

}



static void dccp_ackvec_insert_avr(struct dccp_ackvec *av,

				   struct dccp_ackvec_record *avr)

{

	/*

	 * AVRs are sorted by seqno. Since we are sending them in order, we

	 * just add the AVR at the head of the list.

	 * -sorbo.

/**

 * dccp_ackvec_update_records  -  Record information about sent Ack Vectors

 * @av:		Ack Vector records to update

 * @seqno:	Sequence number of the packet carrying the Ack Vector just sent

 * @nonce_sum:	The sum of all buffer nonces contained in the Ack Vector

 */

	if (!list_empty(&av->av_records)) {

		const struct dccp_ackvec_record *head =

					list_entry(av->av_records.next,

						   struct dccp_ackvec_record,

						   avr_node);

		BUG_ON(before48(avr->avr_ack_seqno, head->avr_ack_seqno));

	}



	list_add(&avr->avr_node, &av->av_records);

}



int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)

int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seqno, u8 nonce_sum)

{

	struct dccp_sock *dp = dccp_sk(sk);

	struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;

	/* Figure out how many options do we need to represent the ackvec */

	const u8 nr_opts = DIV_ROUND_UP(av->av_vec_len, DCCP_SINGLE_OPT_MAXLEN);

	u16 len = av->av_vec_len + 2 * nr_opts;

	u8 i, nonce = 0;

	const unsigned char *tail, *from;

	unsigned char *to;

	struct dccp_ackvec_record *avr;



	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)

		return -1;



	avr = kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC);

	if (avr == NULL)

		return -1;



	DCCP_SKB_CB(skb)->dccpd_opt_len += len;



	to   = skb_push(skb, len);

	len  = av->av_vec_len;

	from = av->av_buf + av->av_buf_head;

	tail = av->av_buf + DCCPAV_MAX_ACKVEC_LEN;



	for (i = 0; i < nr_opts; ++i) {

		int copylen = len;



		if (len > DCCP_SINGLE_OPT_MAXLEN)

			copylen = DCCP_SINGLE_OPT_MAXLEN;



		/*

		 * RFC 4340, 12.2: Encode the Nonce Echo for this Ack Vector via

		 * its type; ack_nonce is the sum of all individual buf_nonce's.

		 */

		nonce ^= av->av_buf_nonce[i];



		*to++ = DCCPO_ACK_VECTOR_0 + av->av_buf_nonce[i];

		*to++ = copylen + 2;



		/* Check if buf_head wraps */

		if (from + copylen > tail) {

			const u16 tailsize = tail - from;



			memcpy(to, from, tailsize);

			to	+= tailsize;

			len	-= tailsize;

			copylen	-= tailsize;

			from	= av->av_buf;

		}



		memcpy(to, from, copylen);

		from += copylen;

		to   += copylen;

		len  -= copylen;

	}

		return -ENOBUFS;



	/*

	 * Each sent Ack Vector is recorded in the list, as per A.2 of RFC 4340.

	 */

	avr->avr_ack_seqno  = DCCP_SKB_CB(skb)->dccpd_seq;

	avr->avr_ack_seqno  = seqno;

	avr->avr_ack_ptr    = av->av_buf_head;

	avr->avr_ack_ackno  = av->av_buf_ackno;

	avr->avr_ack_nonce  = nonce;

	avr->avr_ack_nonce  = nonce_sum;

	avr->avr_ack_runlen = dccp_ackvec_runlen(av->av_buf + av->av_buf_head);

	/*

	 * Since GSS is incremented for each packet, the list is automatically

	 * arranged in descending order of @ack_seqno.

	 */

	list_add(&avr->avr_node, &av->av_records);



	dccp_ackvec_insert_avr(av, avr);



	dccp_pr_debug("%s ACK Vector 0, len=%d, ack_seqno=%llu, "

		      "ack_ackno=%llu\n",

		      dccp_role(sk), avr->avr_ack_runlen,

	dccp_pr_debug("Added Vector, ack_seqno=%llu, ack_ackno=%llu (rl=%u)\n",

		      (unsigned long long)avr->avr_ack_seqno,

		      (unsigned long long)avr->avr_ack_ackno);

		      (unsigned long long)avr->avr_ack_ackno,

		      avr->avr_ack_runlen);

	return 0;

}

net/dccp/ackvec.h

+1 −1
Original line number Diff line number Diff line
@@ -111,7 +111,7 @@ extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, 
			     u64 *ackno, const u8 opt,

			     const u8 *value, const u8 len);



extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);

extern int  dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum);



static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)

{

net/dccp/options.c

+60 −0
Original line number Diff line number Diff line
@@ -425,6 +425,66 @@ static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp, 
	return 0;

}



static int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)

{

	struct dccp_sock *dp = dccp_sk(sk);

	struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;

	/* Figure out how many options do we need to represent the ackvec */

	const u8 nr_opts = DIV_ROUND_UP(av->av_vec_len, DCCP_SINGLE_OPT_MAXLEN);

	u16 len = av->av_vec_len + 2 * nr_opts;

	u8 i, nonce = 0;

	const unsigned char *tail, *from;

	unsigned char *to;



	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);

	len  = av->av_vec_len;

	from = av->av_buf + av->av_buf_head;

	tail = av->av_buf + DCCPAV_MAX_ACKVEC_LEN;



	for (i = 0; i < nr_opts; ++i) {

		int copylen = len;



		if (len > DCCP_SINGLE_OPT_MAXLEN)

			copylen = DCCP_SINGLE_OPT_MAXLEN;



		/*

		 * RFC 4340, 12.2: Encode the Nonce Echo for this Ack Vector via

		 * its type; ack_nonce is the sum of all individual buf_nonce's.

		 */

		nonce ^= av->av_buf_nonce[i];



		*to++ = DCCPO_ACK_VECTOR_0 + av->av_buf_nonce[i];

		*to++ = copylen + 2;



		/* Check if buf_head wraps */

		if (from + copylen > tail) {

			const u16 tailsize = tail - from;



			memcpy(to, from, tailsize);

			to	+= tailsize;

			len	-= tailsize;

			copylen	-= tailsize;

			from	= av->av_buf;

		}



		memcpy(to, from, copylen);

		from += copylen;

		to   += copylen;

		len  -= copylen;

	}

	/*

	 * Each sent Ack Vector is recorded in the list, as per A.2 of RFC 4340.

	 */

	if (dccp_ackvec_update_records(av, DCCP_SKB_CB(skb)->dccpd_seq, nonce))

		return -ENOBUFS;

	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

CRA Git | Maintained and supported by SUSTech CRA and CCSE