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[DCCP]: Send SYNCACK packets in response to SYNC packets
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Also fix step 6 when receiving SYNC or SYNCACK packets, i.e. we were not using
the updated swl.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Arnaldo Carvalho de Melo authored and David S. Miller committed Aug 29, 2005
1 parent ba602a8 commit e92ae93
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Showing 4 changed files with 40 additions and 19 deletions.
3 changes: 2 additions & 1 deletion net/dccp/dccp.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
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33 changes: 25 additions & 8 deletions net/dccp/input.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
}

Expand All @@ -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
Expand All @@ -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
Expand All @@ -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;
Expand All @@ -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;
}

Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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;
}

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18 changes: 10 additions & 8 deletions net/dccp/ipv4.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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 */
}

Expand Down Expand Up @@ -1008,15 +1008,15 @@ 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;
}

dh = dccp_hdr(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;
}

Expand All @@ -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;
}
Expand All @@ -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;
}

Expand Down
5 changes: 3 additions & 2 deletions net/dccp/output.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -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);
Expand Down

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