[DCCP]: Move the ack vector code to net/dccp/ackvec.[ch]

Isolating it, that will be used when we introduce a CCID2 (TCP-Like)
implementation.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 433 deletions

diff --git a/net/dccp/options.c b/net/dccp/options.c
index d4c4242d8dd..c480c506a4a 100644
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -18,15 +18,10 @@
 #include <linux/kernel.h>
 #include <linux/skbuff.h>
 
+#include "ackvec.h"
 #include "ccid.h"
 #include "dccp.h"
 
-static void dccp_ackpkts_check_rcv_ackvector(struct dccp_ackpkts *ap,
-					     struct sock *sk,
-					     const u64 ackno,
-					     const unsigned char len,
-					     const unsigned char *vector);
-
 /* 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,
@@ -113,25 +108,13 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
 				      opt_recv->dccpor_ndp);
 			break;
 		case DCCPO_ACK_VECTOR_0:
-			if (len > DCCP_MAX_ACK_VECTOR_LEN)
-				goto out_invalid_option;
-
+		case DCCPO_ACK_VECTOR_1:
 			if (pkt_type == DCCP_PKT_DATA)
 				continue;
 
-			opt_recv->dccpor_ack_vector_len = len;
-			opt_recv->dccpor_ack_vector_idx = value - options;
-
-			dccp_pr_debug("%sACK vector 0, len=%d, ack_ackno=%llu\n",
-				      debug_prefix, len,
-				      (unsigned long long)
-				      DCCP_SKB_CB(skb)->dccpd_ack_seq);
-			dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq,
-					     value, len);
-			dccp_ackpkts_check_rcv_ackvector(dp->dccps_hc_rx_ackpkts,
-							 sk,
-						 DCCP_SKB_CB(skb)->dccpd_ack_seq,
-							 len, value);
+			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)
@@ -352,86 +335,6 @@ void dccp_insert_option_elapsed_time(struct sock *sk,
 
 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
 
-static void dccp_insert_option_ack_vector(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 dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
-	int len = ap->dccpap_buf_vector_len + 2;
-	struct timeval now;
-	u32 elapsed_time;
-	unsigned char *to, *from;
-
-	dccp_timestamp(sk, &now);
-	elapsed_time = timeval_delta(&now, &ap->dccpap_time) / 10;
-
-	if (elapsed_time != 0)
-		dccp_insert_option_elapsed_time(sk, skb, elapsed_time);
-
-	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
-		LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
-					 "insert ACK Vector!\n");
-		return;
-	}
-
-	/*
-	 * XXX: now we have just one ack vector sent record, so
-	 * we have to wait for it to be cleared.
-	 *
-	 * Of course this is not acceptable, but this is just for
-	 * basic testing now.
-	 */
-	if (ap->dccpap_ack_seqno != DCCP_MAX_SEQNO + 1)
-		return;
-
-	DCCP_SKB_CB(skb)->dccpd_opt_len += len;
-
-	to    = skb_push(skb, len);
-	*to++ = DCCPO_ACK_VECTOR_0;
-	*to++ = len;
-
-	len  = ap->dccpap_buf_vector_len;
-	from = ap->dccpap_buf + ap->dccpap_buf_head;
-
-	/* Check if buf_head wraps */
-	if (ap->dccpap_buf_head + len > ap->dccpap_buf_len) {
-		const unsigned int tailsize = (ap->dccpap_buf_len -
-					       ap->dccpap_buf_head);
-
-		memcpy(to, from, tailsize);
-		to   += tailsize;
-		len  -= tailsize;
-		from = ap->dccpap_buf;
-	}
-
-	memcpy(to, from, len);
-	/*
-	 *	From draft-ietf-dccp-spec-11.txt:
-	 *
-	 *	For each acknowledgement it sends, the HC-Receiver will add an
-	 *	acknowledgement record.  ack_seqno will equal the HC-Receiver
-	 *	sequence number it used for the ack packet; ack_ptr will equal
-	 *	buf_head; ack_ackno will equal buf_ackno; and ack_nonce will
-	 *	equal buf_nonce.
-	 *
-	 * This implemention uses just one ack record for now.
-	 */
-	ap->dccpap_ack_seqno	  = DCCP_SKB_CB(skb)->dccpd_seq;
-	ap->dccpap_ack_ptr	  = ap->dccpap_buf_head;
-	ap->dccpap_ack_ackno	  = ap->dccpap_buf_ackno;
-	ap->dccpap_ack_nonce	  = ap->dccpap_buf_nonce;
-	ap->dccpap_ack_vector_len = ap->dccpap_buf_vector_len;
-
-	dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, "
-		      "ack_ackno=%llu\n",
-		      debug_prefix, ap->dccpap_ack_vector_len,
-		      (unsigned long long) ap->dccpap_ack_seqno,
-		      (unsigned long long) ap->dccpap_ack_ackno);
-}
-
 void dccp_timestamp(const struct sock *sk, struct timeval *tv)
 {
 	const struct dccp_sock *dp = dccp_sk(sk);
@@ -528,9 +431,8 @@ void dccp_insert_options(struct sock *sk, struct sk_buff *skb)
 
 	if (!dccp_packet_without_ack(skb)) {
 		if (dp->dccps_options.dccpo_send_ack_vector &&
-		    (dp->dccps_hc_rx_ackpkts->dccpap_buf_ackno !=
-		     DCCP_MAX_SEQNO + 1))
-			dccp_insert_option_ack_vector(sk, skb);
+		    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);
 	}
@@ -557,331 +459,3 @@ void dccp_insert_options(struct sock *sk, struct sk_buff *skb)
 		}
 	}
 }
-
-struct dccp_ackpkts *dccp_ackpkts_alloc(const unsigned int len,
-				        const unsigned int __nocast priority)
-{
-	struct dccp_ackpkts *ap = kmalloc(sizeof(*ap) + len, priority);
-
-	if (ap != NULL) {
-#ifdef CONFIG_IP_DCCP_DEBUG
-		memset(ap->dccpap_buf, 0xFF, len);
-#endif
-		ap->dccpap_buf_len   = len;
-		ap->dccpap_buf_head  =
-			ap->dccpap_buf_tail =
-				ap->dccpap_buf_len - 1;
-		ap->dccpap_buf_ackno =
-			ap->dccpap_ack_ackno =
-				ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
-		ap->dccpap_buf_nonce = ap->dccpap_buf_nonce = 0;
-		ap->dccpap_ack_ptr   = 0;
-		ap->dccpap_time.tv_sec = 0;
-		ap->dccpap_time.tv_usec = 0;
-		ap->dccpap_buf_vector_len = ap->dccpap_ack_vector_len = 0;
-	}
-
-	return ap;
-}
-
-void dccp_ackpkts_free(struct dccp_ackpkts *ap)
-{
-	if (ap != NULL) {
-#ifdef CONFIG_IP_DCCP_DEBUG
-		memset(ap, 0xFF, sizeof(*ap) + ap->dccpap_buf_len);
-#endif
-		kfree(ap);
-	}
-}
-
-static inline u8 dccp_ackpkts_state(const struct dccp_ackpkts *ap,
-				    const unsigned int index)
-{
-	return ap->dccpap_buf[index] & DCCP_ACKPKTS_STATE_MASK;
-}
-
-static inline u8 dccp_ackpkts_len(const struct dccp_ackpkts *ap,
-				  const unsigned int index)
-{
-	return ap->dccpap_buf[index] & DCCP_ACKPKTS_LEN_MASK;
-}
-
-/*
- * If several packets are missing, the HC-Receiver may prefer to enter multiple
- * bytes with run length 0, rather than a single byte with a larger run length;
- * this simplifies table updates if one of the missing packets arrives.
- */
-static inline int dccp_ackpkts_set_buf_head_state(struct dccp_ackpkts *ap,
-						  const unsigned int packets,
-						  const unsigned char state)
-{
-	unsigned int gap;
-	signed long new_head;
-
-	if (ap->dccpap_buf_vector_len + packets > ap->dccpap_buf_len)
-		return -ENOBUFS;
-
-	gap	 = packets - 1;
-	new_head = ap->dccpap_buf_head - packets;
-
-	if (new_head < 0) {
-		if (gap > 0) {
-			memset(ap->dccpap_buf, DCCP_ACKPKTS_STATE_NOT_RECEIVED,
-			       gap + new_head + 1);
-			gap = -new_head;
-		}
-		new_head += ap->dccpap_buf_len;
-	} 
-
-	ap->dccpap_buf_head = new_head;
-
-	if (gap > 0)
-		memset(ap->dccpap_buf + ap->dccpap_buf_head + 1,
-		       DCCP_ACKPKTS_STATE_NOT_RECEIVED, gap);
-
-	ap->dccpap_buf[ap->dccpap_buf_head] = state;
-	ap->dccpap_buf_vector_len += packets;
-	return 0;
-}
-
-/*
- * Implements the draft-ietf-dccp-spec-11.txt Appendix A
- */
-int dccp_ackpkts_add(struct dccp_ackpkts *ap, const struct sock *sk,
-		     u64 ackno, u8 state)
-{
-	/*
-	 * Check at the right places if the buffer is full, if it is, tell the
-	 * caller to start dropping packets till the HC-Sender acks our ACK
-	 * vectors, when we will free up space in dccpap_buf.
-	 *
-	 * We may well decide to do buffer compression, etc, but for now lets
-	 * just drop.
-	 *
-	 * From Appendix A:
-	 *
-	 *	Of course, the circular buffer may overflow, either when the
-	 *	HC-Sender is sending data at a very high rate, when the
-	 *	HC-Receiver's acknowledgements are not reaching the HC-Sender,
-	 *	or when the HC-Sender is forgetting to acknowledge those acks
-	 *	(so the HC-Receiver is unable to clean up old state). In this
-	 *	case, the HC-Receiver should either compress the buffer (by
-	 *	increasing run lengths when possible), transfer its state to
-	 *	a larger buffer, or, as a last resort, drop all received
-	 *	packets, without processing them whatsoever, until its buffer
-	 *	shrinks again.
-	 */
-
-	/* See if this is the first ackno being inserted */
-	if (ap->dccpap_buf_vector_len == 0) {
-		ap->dccpap_buf[ap->dccpap_buf_head] = state;
-		ap->dccpap_buf_vector_len = 1;
-	} else if (after48(ackno, ap->dccpap_buf_ackno)) {
-		const u64 delta = dccp_delta_seqno(ap->dccpap_buf_ackno,
-						   ackno);
-
-		/*
-		 * Look if the state of this packet is the same as the
-		 * previous ackno and if so if we can bump the head len.
-		 */
-		if (delta == 1 &&
-		    dccp_ackpkts_state(ap, ap->dccpap_buf_head) == state &&
-		    (dccp_ackpkts_len(ap, ap->dccpap_buf_head) <
-		     DCCP_ACKPKTS_LEN_MASK))
-			ap->dccpap_buf[ap->dccpap_buf_head]++;
-		else if (dccp_ackpkts_set_buf_head_state(ap, delta, state))
-			return -ENOBUFS;
-	} else {
-		/*
-		 * A.1.2.  Old Packets
-		 *
-		 *	When a packet with Sequence Number S arrives, and
-		 *	S <= buf_ackno, the HC-Receiver will scan the table
-		 *	for the byte corresponding to S. (Indexing structures
-		 *	could reduce the complexity of this scan.)
-		 */
-		u64 delta = dccp_delta_seqno(ackno, ap->dccpap_buf_ackno);
-		unsigned int index = ap->dccpap_buf_head;
-
-		while (1) {
-			const u8 len = dccp_ackpkts_len(ap, index);
-			const u8 state = dccp_ackpkts_state(ap, index);
-			/*
-			 * valid packets not yet in dccpap_buf have a reserved
-			 * entry, with a len equal to 0.
-			 */
-			if (state == DCCP_ACKPKTS_STATE_NOT_RECEIVED &&
-			    len == 0 && delta == 0) { /* Found our
-							 reserved seat! */
-				dccp_pr_debug("Found %llu reserved seat!\n",
-					      (unsigned long long) ackno);
-				ap->dccpap_buf[index] = state;
-				goto out;
-			}
-			/* len == 0 means one packet */
-			if (delta < len + 1)
-				goto out_duplicate;
-
-			delta -= len + 1;
-			if (++index == ap->dccpap_buf_len)
-				index = 0;
-		}
-	}
-
-	ap->dccpap_buf_ackno = ackno;
-	dccp_timestamp(sk, &ap->dccpap_time);
-out:
-	dccp_pr_debug("");
-	dccp_ackpkts_print(ap);
-	return 0;
-
-out_duplicate:
-	/* Duplicate packet */
-	dccp_pr_debug("Received a dup or already considered lost "
-		      "packet: %llu\n", (unsigned long long) ackno);
-	return -EILSEQ;
-}
-
-#ifdef CONFIG_IP_DCCP_DEBUG
-void dccp_ackvector_print(const u64 ackno, const unsigned char *vector,
-			  int len)
-{
-	if (!dccp_debug)
-		return;
-
-	printk("ACK vector len=%d, ackno=%llu |", len,
-	       (unsigned long long) ackno);
-
-	while (len--) {
-		const u8 state = (*vector & DCCP_ACKPKTS_STATE_MASK) >> 6;
-		const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK);
-
-		printk("%d,%d|", state, rl);
-		++vector;
-	}
-
-	printk("\n");
-}
-
-void dccp_ackpkts_print(const struct dccp_ackpkts *ap)
-{
-	dccp_ackvector_print(ap->dccpap_buf_ackno,
-			     ap->dccpap_buf + ap->dccpap_buf_head,
-			     ap->dccpap_buf_vector_len);
-}
-#endif
-
-static void dccp_ackpkts_trow_away_ack_record(struct dccp_ackpkts *ap)
-{
-	/*
-	 * As we're keeping track of the ack vector size
-	 * (dccpap_buf_vector_len) and the sent ack vector size
-	 * (dccpap_ack_vector_len) we don't need dccpap_buf_tail at all, but
-	 * keep this code here as in the future we'll implement a vector of
-	 * ack records, as suggested in draft-ietf-dccp-spec-11.txt
-	 * Appendix A. -acme
-	 */
-#if 0
-	ap->dccpap_buf_tail = ap->dccpap_ack_ptr + 1;
-	if (ap->dccpap_buf_tail >= ap->dccpap_buf_len)
-		ap->dccpap_buf_tail -= ap->dccpap_buf_len;
-#endif
-	ap->dccpap_buf_vector_len -= ap->dccpap_ack_vector_len;
-}
-
-void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap, struct sock *sk,
-				 u64 ackno)
-{
-	/* Check if we actually sent an ACK vector */
-	if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1)
-		return;
-
-	if (ackno == ap->dccpap_ack_seqno) {
-#ifdef CONFIG_IP_DCCP_DEBUG
-		struct dccp_sock *dp = dccp_sk(sk);
-		const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
-					"CLIENT rx ack: " : "server rx ack: ";
-#endif
-		dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, "
-			      "ack_ackno=%llu, ACKED!\n",
-			      debug_prefix, 1,
-			      (unsigned long long) ap->dccpap_ack_seqno,
-			      (unsigned long long) ap->dccpap_ack_ackno);
-		dccp_ackpkts_trow_away_ack_record(ap);
-		ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
-	}
-}
-
-static void dccp_ackpkts_check_rcv_ackvector(struct dccp_ackpkts *ap,
-					     struct sock *sk, u64 ackno,
-					     const unsigned char len,
-					     const unsigned char *vector)
-{
-	unsigned char i;
-
-	/* Check if we actually sent an ACK vector */
-	if (ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1)
-		return;
-	/*
-	 * We're in the receiver half connection, so if the received an ACK
-	 * vector ackno (e.g. 50) before dccpap_ack_seqno (e.g. 52), we're
-	 * not interested.
-	 *
-	 * Extra explanation with example:
-	 * 
-	 * if we received an ACK vector with ackno 50, it can only be acking
-	 * 50, 49, 48, etc, not 52 (the seqno for the ACK vector we sent).
-	 */
-	/* dccp_pr_debug("is %llu < %llu? ", ackno, ap->dccpap_ack_seqno); */
-	if (before48(ackno, ap->dccpap_ack_seqno)) {
-		/* dccp_pr_debug_cat("yes\n"); */
-		return;
-	}
-	/* dccp_pr_debug_cat("no\n"); */
-
-	i = len;
-	while (i--) {
-		const u8 rl = (*vector & DCCP_ACKPKTS_LEN_MASK);
-		u64 ackno_end_rl;
-
-		dccp_set_seqno(&ackno_end_rl, ackno - rl);
-
-		/*
-		 * dccp_pr_debug("is %llu <= %llu <= %llu? ", ackno_end_rl,
-		 * ap->dccpap_ack_seqno, ackno);
-		 */
-		if (between48(ap->dccpap_ack_seqno, ackno_end_rl, ackno)) {
-			const u8 state = (*vector &
-					  DCCP_ACKPKTS_STATE_MASK) >> 6;
-			/* dccp_pr_debug_cat("yes\n"); */
-
-			if (state != DCCP_ACKPKTS_STATE_NOT_RECEIVED) {
-#ifdef CONFIG_IP_DCCP_DEBUG
-				struct dccp_sock *dp = dccp_sk(sk);
-				const char *debug_prefix =
-					dp->dccps_role == DCCP_ROLE_CLIENT ?
-					"CLIENT rx ack: " : "server rx ack: ";
-#endif
-				dccp_pr_debug("%sACK vector 0, len=%d, "
-					      "ack_seqno=%llu, ack_ackno=%llu, "
-					      "ACKED!\n",
-					      debug_prefix, len,
-					      (unsigned long long)
-					      ap->dccpap_ack_seqno,
-					      (unsigned long long)
-					      ap->dccpap_ack_ackno);
-				dccp_ackpkts_trow_away_ack_record(ap);
-			}
-			/*
-			 * If dccpap_ack_seqno was not received, no problem
-			 * we'll send another ACK vector.
-			 */
-			ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
-			break;
-		}
-		/* dccp_pr_debug_cat("no\n"); */
-
-		dccp_set_seqno(&ackno, ackno_end_rl - 1);
-		++vector;
-	}
-}