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Commit e92ae93a authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo Committed by David S. Miller
Browse files

[DCCP]: Send SYNCACK packets in response to SYNC packets 



Also fix step 6 when receiving SYNC or SYNCACK packets, i.e. we were not using
the updated swl.

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ba602a81

net/dccp/dccp.h

+2 −1
Original line number Diff line number Diff line
@@ -122,7 +122,8 @@ extern int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb); 
extern int dccp_send_response(struct sock *sk);

extern void dccp_send_ack(struct sock *sk);

extern void dccp_send_delayed_ack(struct sock *sk);

extern void dccp_send_sync(struct sock *sk, u64 seq);

extern void dccp_send_sync(struct sock *sk, const u64 seq,

			   const enum dccp_pkt_type pkt_type);



extern int dccp_write_xmit(struct sock *sk, struct sk_buff *skb,

			   const int len);

net/dccp/input.c

+25 −8
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb) 
	 *	  Drop packet and return

	 */

	if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) {

		dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq);

		dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);

		return;

	}
@@ -76,8 +76,7 @@ static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) 
{

	const struct dccp_hdr *dh = dccp_hdr(skb);

	struct dccp_sock *dp = dccp_sk(sk);

	u64 lswl = dp->dccps_swl;

	u64 lawl = dp->dccps_awl;

	u64 lswl, lawl;



	/*

	 *   Step 5: Prepare sequence numbers for Sync
@@ -99,6 +98,8 @@ static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) 
			dccp_update_gsr(sk, DCCP_SKB_CB(skb)->dccpd_seq);

		else

			return -1;

	}

	

	/*

	 *   Step 6: Check sequence numbers

	 *      Let LSWL = S.SWL and LAWL = S.AWL
@@ -113,7 +114,10 @@ static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) 
	 *	  Send Sync packet acknowledging P.seqno

	 *	  Drop packet and return

	 */

	} else if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||

	lswl = dp->dccps_swl;

	lawl = dp->dccps_awl;



	if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||

		   dh->dccph_type == DCCP_PKT_CLOSE ||

		   dh->dccph_type == DCCP_PKT_RESET) {

		lswl = dp->dccps_gsr;
@@ -132,8 +136,8 @@ static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb) 
		     DCCP_PKT_WITHOUT_ACK_SEQ))

			dp->dccps_gar = DCCP_SKB_CB(skb)->dccpd_ack_seq;

	} else {

		dccp_pr_debug("Step 6 failed, sending SYNC...\n");

		dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq);

		LIMIT_NETDEBUG("Step 6 failed, sending SYNC...\n");

		dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);

		return -1;

	}
@@ -242,9 +246,21 @@ int dccp_rcv_established(struct sock *sk, struct sk_buff *skb, 
check_seq:

		if (!before48(DCCP_SKB_CB(skb)->dccpd_seq, dp->dccps_osr)) {

send_sync:

			dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq);

			dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,

				       DCCP_PKT_SYNC);

		}

		break;

	case DCCP_PKT_SYNC:

		dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,

			       DCCP_PKT_SYNCACK);

		/*

		 * From the draft:

		 *

		 * As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets

		 * MAY have non-zero-length application data areas, whose

		 * contents * receivers MUST ignore.

		 */

		goto discard;

	}



	DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
@@ -517,7 +533,8 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, 
		     dh->dccph_type == DCCP_PKT_REQUEST) ||

		    (sk->sk_state == DCCP_RESPOND &&

		     dh->dccph_type == DCCP_PKT_DATA)) {

		dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq);

		dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,

			       DCCP_PKT_SYNC);

		goto discard;

	}

net/dccp/ipv4.c

+10 −8
Original line number Diff line number Diff line
@@ -376,7 +376,7 @@ static inline void dccp_do_pmtu_discovery(struct sock *sk, 
		 *	probing, since DCCP-Sync probes do not risk application

		 *	data loss.

		 */

		dccp_send_sync(sk, dp->dccps_gsr);

		dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);

	} /* else let the usual retransmit timer handle it */

}
@@ -1008,7 +1008,7 @@ static inline int dccp_invalid_packet(struct sk_buff *skb) 
		return 1;



	if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {

		dccp_pr_debug("pskb_may_pull failed\n");

		printk(KERN_WARNING "DCCP: pskb_may_pull failed\n");

		return 1;

	}
@@ -1016,7 +1016,7 @@ static inline int dccp_invalid_packet(struct sk_buff *skb) 


	/* If the packet type is not understood, drop packet and return */

	if (dh->dccph_type >= DCCP_PKT_INVALID) {

		dccp_pr_debug("invalid packet type\n");

		printk(KERN_WARNING "DCCP: invalid packet type\n");

		return 1;

	}
@@ -1025,12 +1025,13 @@ static inline int dccp_invalid_packet(struct sk_buff *skb) 
	 * packet, drop packet and return

	 */

	if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {

		dccp_pr_debug("Offset(%u) too small 1\n", dh->dccph_doff);

		printk(KERN_WARNING "DCCP: Offset(%u) too small 1\n",

		       dh->dccph_doff);

		return 1;

	}



	if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {

		dccp_pr_debug("P.Data Offset(%u) too small 2\n",

		printk(KERN_WARNING "DCCP: P.Data Offset(%u) too small 2\n",

			      dh->dccph_doff);

		return 1;

	}
@@ -1045,15 +1046,16 @@ static inline int dccp_invalid_packet(struct sk_buff *skb) 
	    dh->dccph_type != DCCP_PKT_DATA &&

	    dh->dccph_type != DCCP_PKT_ACK &&

	    dh->dccph_type != DCCP_PKT_DATAACK) {

		dccp_pr_debug("P.type (%s) not Data, Ack nor DataAck and "

			      "P.X == 0\n", dccp_packet_name(dh->dccph_type));

		printk(KERN_WARNING "DCCP: P.type (%s) not Data, Ack nor "

				    "DataAck and P.X == 0\n",

		       dccp_packet_name(dh->dccph_type));

		return 1;

	}



	/* If the header checksum is incorrect, drop packet and return */

	if (dccp_v4_verify_checksum(skb, skb->nh.iph->saddr,

				    skb->nh.iph->daddr) < 0) {

		dccp_pr_debug("header checksum is incorrect\n");

		printk(KERN_WARNING "DCCP: header checksum is incorrect\n");

		return 1;

	}

net/dccp/output.c

+3 −2
Original line number Diff line number Diff line
@@ -404,7 +404,8 @@ void dccp_send_delayed_ack(struct sock *sk) 
	sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);

}



void dccp_send_sync(struct sock *sk, u64 seq)

void dccp_send_sync(struct sock *sk, const u64 seq,

		    const enum dccp_pkt_type pkt_type)

{

	/*

	 * We are not putting this on the write queue, so
@@ -420,7 +421,7 @@ void dccp_send_sync(struct sock *sk, u64 seq) 
	/* Reserve space for headers and prepare control bits. */

	skb_reserve(skb, MAX_DCCP_HEADER);

	skb->csum = 0;

	DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_SYNC;

	DCCP_SKB_CB(skb)->dccpd_type = pkt_type;

	DCCP_SKB_CB(skb)->dccpd_seq = seq;



	skb_set_owner_w(skb, sk);