diff options
Diffstat (limited to 'net/dccp/output.c')
| -rw-r--r-- | net/dccp/output.c | 53 |
1 files changed, 31 insertions, 22 deletions
diff --git a/net/dccp/output.c b/net/dccp/output.c index fe20068..d06945c 100644 --- a/net/dccp/output.c +++ b/net/dccp/output.c @@ -53,8 +53,11 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb) dccp_packet_hdr_len(dcb->dccpd_type); int err, set_ack = 1; u64 ackno = dp->dccps_gsr; - - dccp_inc_seqno(&dp->dccps_gss); + /* + * Increment GSS here already in case the option code needs it. + * Update GSS for real only if option processing below succeeds. + */ + dcb->dccpd_seq = ADD48(dp->dccps_gss, 1); switch (dcb->dccpd_type) { case DCCP_PKT_DATA: @@ -66,6 +69,9 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb) case DCCP_PKT_REQUEST: set_ack = 0; + /* Use ISS on the first (non-retransmitted) Request. */ + if (icsk->icsk_retransmits == 0) + dcb->dccpd_seq = dp->dccps_iss; /* fall through */ case DCCP_PKT_SYNC: @@ -84,8 +90,6 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb) break; } - dcb->dccpd_seq = dp->dccps_gss; - if (dccp_insert_options(sk, skb)) { kfree_skb(skb); return -EPROTO; @@ -103,7 +107,7 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb) /* XXX For now we're using only 48 bits sequence numbers */ dh->dccph_x = 1; - dp->dccps_awh = dp->dccps_gss; + dccp_update_gss(sk, dcb->dccpd_seq); dccp_hdr_set_seq(dh, dp->dccps_gss); if (set_ack) dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), ackno); @@ -112,6 +116,11 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb) case DCCP_PKT_REQUEST: dccp_hdr_request(skb)->dccph_req_service = dp->dccps_service; + /* + * Limit Ack window to ISS <= P.ackno <= GSS, so that + * only Responses to Requests we sent are considered. + */ + dp->dccps_awl = dp->dccps_iss; break; case DCCP_PKT_RESET: dccp_hdr_reset(skb)->dccph_reset_code = @@ -284,14 +293,26 @@ void dccp_write_xmit(struct sock *sk, int block) } } -int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb) +/** + * dccp_retransmit_skb - Retransmit Request, Close, or CloseReq packets + * There are only four retransmittable packet types in DCCP: + * - Request in client-REQUEST state (sec. 8.1.1), + * - CloseReq in server-CLOSEREQ state (sec. 8.3), + * - Close in node-CLOSING state (sec. 8.3), + * - Acks in client-PARTOPEN state (sec. 8.1.5, handled by dccp_delack_timer()). + * This function expects sk->sk_send_head to contain the original skb. + */ +int dccp_retransmit_skb(struct sock *sk) { + WARN_ON(sk->sk_send_head == NULL); + if (inet_csk(sk)->icsk_af_ops->rebuild_header(sk) != 0) return -EHOSTUNREACH; /* Routing failure or similar. */ - return dccp_transmit_skb(sk, (skb_cloned(skb) ? - pskb_copy(skb, GFP_ATOMIC): - skb_clone(skb, GFP_ATOMIC))); + /* this count is used to distinguish original and retransmitted skb */ + inet_csk(sk)->icsk_retransmits++; + + return dccp_transmit_skb(sk, skb_clone(sk->sk_send_head, GFP_ATOMIC)); } struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, @@ -437,19 +458,7 @@ static inline void dccp_connect_init(struct sock *sk) dccp_sync_mss(sk, dst_mtu(dst)); - /* - * SWL and AWL are initially adjusted so that they are not less than - * the initial Sequence Numbers received and sent, respectively: - * SWL := max(GSR + 1 - floor(W/4), ISR), - * AWL := max(GSS - W' + 1, ISS). - * These adjustments MUST be applied only at the beginning of the - * connection. - */ - dccp_update_gss(sk, dp->dccps_iss); - dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss)); - - /* S.GAR - greatest valid acknowledgement number received on a non-Sync; - * initialized to S.ISS (sec. 8.5) */ + /* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */ dp->dccps_gar = dp->dccps_iss; icsk->icsk_retransmits = 0; |