| /* |
| * net/dccp/output.c |
| * |
| * An implementation of the DCCP protocol |
| * Arnaldo Carvalho de Melo <acme@conectiva.com.br> |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| */ |
| |
| #include <linux/dccp.h> |
| #include <linux/kernel.h> |
| #include <linux/skbuff.h> |
| #include <linux/slab.h> |
| |
| #include <net/inet_sock.h> |
| #include <net/sock.h> |
| |
| #include "ackvec.h" |
| #include "ccid.h" |
| #include "dccp.h" |
| |
| static inline void dccp_event_ack_sent(struct sock *sk) |
| { |
| inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); |
| } |
| |
| static void dccp_skb_entail(struct sock *sk, struct sk_buff *skb) |
| { |
| skb_set_owner_w(skb, sk); |
| WARN_ON(sk->sk_send_head); |
| sk->sk_send_head = skb; |
| } |
| |
| /* |
| * All SKB's seen here are completely headerless. It is our |
| * job to build the DCCP header, and pass the packet down to |
| * IP so it can do the same plus pass the packet off to the |
| * device. |
| */ |
| static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb) |
| { |
| if (likely(skb != NULL)) { |
| const struct inet_sock *inet = inet_sk(sk); |
| const struct inet_connection_sock *icsk = inet_csk(sk); |
| struct dccp_sock *dp = dccp_sk(sk); |
| struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); |
| struct dccp_hdr *dh; |
| /* XXX For now we're using only 48 bits sequence numbers */ |
| const u32 dccp_header_size = sizeof(*dh) + |
| sizeof(struct dccp_hdr_ext) + |
| dccp_packet_hdr_len(dcb->dccpd_type); |
| int err, set_ack = 1; |
| u64 ackno = dp->dccps_gsr; |
| /* |
| * 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: |
| set_ack = 0; |
| /* fall through */ |
| case DCCP_PKT_DATAACK: |
| case DCCP_PKT_RESET: |
| break; |
| |
| 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: |
| case DCCP_PKT_SYNCACK: |
| ackno = dcb->dccpd_ack_seq; |
| /* fall through */ |
| default: |
| /* |
| * Set owner/destructor: some skbs are allocated via |
| * alloc_skb (e.g. when retransmission may happen). |
| * Only Data, DataAck, and Reset packets should come |
| * through here with skb->sk set. |
| */ |
| WARN_ON(skb->sk); |
| skb_set_owner_w(skb, sk); |
| break; |
| } |
| |
| if (dccp_insert_options(sk, skb)) { |
| kfree_skb(skb); |
| return -EPROTO; |
| } |
| |
| |
| /* Build DCCP header and checksum it. */ |
| dh = dccp_zeroed_hdr(skb, dccp_header_size); |
| dh->dccph_type = dcb->dccpd_type; |
| dh->dccph_sport = inet->inet_sport; |
| dh->dccph_dport = inet->inet_dport; |
| dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4; |
| dh->dccph_ccval = dcb->dccpd_ccval; |
| dh->dccph_cscov = dp->dccps_pcslen; |
| /* XXX For now we're using only 48 bits sequence numbers */ |
| dh->dccph_x = 1; |
| |
| 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); |
| |
| switch (dcb->dccpd_type) { |
| 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 = |
| dcb->dccpd_reset_code; |
| break; |
| } |
| |
| icsk->icsk_af_ops->send_check(sk, skb); |
| |
| if (set_ack) |
| dccp_event_ack_sent(sk); |
| |
| DCCP_INC_STATS(DCCP_MIB_OUTSEGS); |
| |
| err = icsk->icsk_af_ops->queue_xmit(skb, 0); |
| return net_xmit_eval(err); |
| } |
| return -ENOBUFS; |
| } |
| |
| /** |
| * dccp_determine_ccmps - Find out about CCID-specfic packet-size limits |
| * We only consider the HC-sender CCID for setting the CCMPS (RFC 4340, 14.), |
| * since the RX CCID is restricted to feedback packets (Acks), which are small |
| * in comparison with the data traffic. A value of 0 means "no current CCMPS". |
| */ |
| static u32 dccp_determine_ccmps(const struct dccp_sock *dp) |
| { |
| const struct ccid *tx_ccid = dp->dccps_hc_tx_ccid; |
| |
| if (tx_ccid == NULL || tx_ccid->ccid_ops == NULL) |
| return 0; |
| return tx_ccid->ccid_ops->ccid_ccmps; |
| } |
| |
| unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu) |
| { |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| struct dccp_sock *dp = dccp_sk(sk); |
| u32 ccmps = dccp_determine_ccmps(dp); |
| u32 cur_mps = ccmps ? min(pmtu, ccmps) : pmtu; |
| |
| /* Account for header lengths and IPv4/v6 option overhead */ |
| cur_mps -= (icsk->icsk_af_ops->net_header_len + icsk->icsk_ext_hdr_len + |
| sizeof(struct dccp_hdr) + sizeof(struct dccp_hdr_ext)); |
| |
| /* |
| * Leave enough headroom for common DCCP header options. |
| * This only considers options which may appear on DCCP-Data packets, as |
| * per table 3 in RFC 4340, 5.8. When running out of space for other |
| * options (eg. Ack Vector which can take up to 255 bytes), it is better |
| * to schedule a separate Ack. Thus we leave headroom for the following: |
| * - 1 byte for Slow Receiver (11.6) |
| * - 6 bytes for Timestamp (13.1) |
| * - 10 bytes for Timestamp Echo (13.3) |
| * - 8 bytes for NDP count (7.7, when activated) |
| * - 6 bytes for Data Checksum (9.3) |
| * - %DCCPAV_MIN_OPTLEN bytes for Ack Vector size (11.4, when enabled) |
| */ |
| cur_mps -= roundup(1 + 6 + 10 + dp->dccps_send_ndp_count * 8 + 6 + |
| (dp->dccps_hc_rx_ackvec ? DCCPAV_MIN_OPTLEN : 0), 4); |
| |
| /* And store cached results */ |
| icsk->icsk_pmtu_cookie = pmtu; |
| dp->dccps_mss_cache = cur_mps; |
| |
| return cur_mps; |
| } |
| |
| EXPORT_SYMBOL_GPL(dccp_sync_mss); |
| |
| void dccp_write_space(struct sock *sk) |
| { |
| read_lock(&sk->sk_callback_lock); |
| |
| if (sk_has_sleeper(sk)) |
| wake_up_interruptible(sk->sk_sleep); |
| /* Should agree with poll, otherwise some programs break */ |
| if (sock_writeable(sk)) |
| sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT); |
| |
| read_unlock(&sk->sk_callback_lock); |
| } |
| |
| /** |
| * dccp_wait_for_ccid - Wait for ccid to tell us we can send a packet |
| * @sk: socket to wait for |
| * @skb: current skb to pass on for waiting |
| * @delay: sleep timeout in milliseconds (> 0) |
| * This function is called by default when the socket is closed, and |
| * when a non-zero linger time is set on the socket. For consistency |
| */ |
| static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, int delay) |
| { |
| struct dccp_sock *dp = dccp_sk(sk); |
| DEFINE_WAIT(wait); |
| unsigned long jiffdelay; |
| int rc; |
| |
| do { |
| dccp_pr_debug("delayed send by %d msec\n", delay); |
| jiffdelay = msecs_to_jiffies(delay); |
| |
| prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE); |
| |
| sk->sk_write_pending++; |
| release_sock(sk); |
| schedule_timeout(jiffdelay); |
| lock_sock(sk); |
| sk->sk_write_pending--; |
| |
| if (sk->sk_err) |
| goto do_error; |
| if (signal_pending(current)) |
| goto do_interrupted; |
| |
| rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); |
| } while ((delay = rc) > 0); |
| out: |
| finish_wait(sk->sk_sleep, &wait); |
| return rc; |
| |
| do_error: |
| rc = -EPIPE; |
| goto out; |
| do_interrupted: |
| rc = -EINTR; |
| goto out; |
| } |
| |
| void dccp_write_xmit(struct sock *sk, int block) |
| { |
| struct dccp_sock *dp = dccp_sk(sk); |
| struct sk_buff *skb; |
| |
| while ((skb = skb_peek(&sk->sk_write_queue))) { |
| int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb); |
| |
| if (err > 0) { |
| if (!block) { |
| sk_reset_timer(sk, &dp->dccps_xmit_timer, |
| msecs_to_jiffies(err)+jiffies); |
| break; |
| } else |
| err = dccp_wait_for_ccid(sk, skb, err); |
| if (err && err != -EINTR) |
| DCCP_BUG("err=%d after dccp_wait_for_ccid", err); |
| } |
| |
| skb_dequeue(&sk->sk_write_queue); |
| if (err == 0) { |
| struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); |
| const int len = skb->len; |
| |
| if (sk->sk_state == DCCP_PARTOPEN) { |
| const u32 cur_mps = dp->dccps_mss_cache - DCCP_FEATNEG_OVERHEAD; |
| /* |
| * See 8.1.5 - Handshake Completion. |
| * |
| * For robustness we resend Confirm options until the client has |
| * entered OPEN. During the initial feature negotiation, the MPS |
| * is smaller than usual, reduced by the Change/Confirm options. |
| */ |
| if (!list_empty(&dp->dccps_featneg) && len > cur_mps) { |
| DCCP_WARN("Payload too large (%d) for featneg.\n", len); |
| dccp_send_ack(sk); |
| dccp_feat_list_purge(&dp->dccps_featneg); |
| } |
| |
| inet_csk_schedule_ack(sk); |
| inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, |
| inet_csk(sk)->icsk_rto, |
| DCCP_RTO_MAX); |
| dcb->dccpd_type = DCCP_PKT_DATAACK; |
| } else if (dccp_ack_pending(sk)) |
| dcb->dccpd_type = DCCP_PKT_DATAACK; |
| else |
| dcb->dccpd_type = DCCP_PKT_DATA; |
| |
| err = dccp_transmit_skb(sk, skb); |
| ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len); |
| if (err) |
| DCCP_BUG("err=%d after ccid_hc_tx_packet_sent", |
| err); |
| } else { |
| dccp_pr_debug("packet discarded due to err=%d\n", err); |
| kfree_skb(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. */ |
| |
| /* 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, |
| struct request_sock *req) |
| { |
| struct dccp_hdr *dh; |
| struct dccp_request_sock *dreq; |
| const u32 dccp_header_size = sizeof(struct dccp_hdr) + |
| sizeof(struct dccp_hdr_ext) + |
| sizeof(struct dccp_hdr_response); |
| struct sk_buff *skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, |
| GFP_ATOMIC); |
| if (skb == NULL) |
| return NULL; |
| |
| /* Reserve space for headers. */ |
| skb_reserve(skb, sk->sk_prot->max_header); |
| |
| skb_dst_set(skb, dst_clone(dst)); |
| |
| dreq = dccp_rsk(req); |
| if (inet_rsk(req)->acked) /* increase ISS upon retransmission */ |
| dccp_inc_seqno(&dreq->dreq_iss); |
| DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE; |
| DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss; |
| |
| /* Resolve feature dependencies resulting from choice of CCID */ |
| if (dccp_feat_server_ccid_dependencies(dreq)) |
| goto response_failed; |
| |
| if (dccp_insert_options_rsk(dreq, skb)) |
| goto response_failed; |
| |
| /* Build and checksum header */ |
| dh = dccp_zeroed_hdr(skb, dccp_header_size); |
| |
| dh->dccph_sport = inet_rsk(req)->loc_port; |
| dh->dccph_dport = inet_rsk(req)->rmt_port; |
| dh->dccph_doff = (dccp_header_size + |
| DCCP_SKB_CB(skb)->dccpd_opt_len) / 4; |
| dh->dccph_type = DCCP_PKT_RESPONSE; |
| dh->dccph_x = 1; |
| dccp_hdr_set_seq(dh, dreq->dreq_iss); |
| dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dreq->dreq_isr); |
| dccp_hdr_response(skb)->dccph_resp_service = dreq->dreq_service; |
| |
| dccp_csum_outgoing(skb); |
| |
| /* We use `acked' to remember that a Response was already sent. */ |
| inet_rsk(req)->acked = 1; |
| DCCP_INC_STATS(DCCP_MIB_OUTSEGS); |
| return skb; |
| response_failed: |
| kfree_skb(skb); |
| return NULL; |
| } |
| |
| EXPORT_SYMBOL_GPL(dccp_make_response); |
| |
| /* answer offending packet in @rcv_skb with Reset from control socket @ctl */ |
| struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *rcv_skb) |
| { |
| struct dccp_hdr *rxdh = dccp_hdr(rcv_skb), *dh; |
| struct dccp_skb_cb *dcb = DCCP_SKB_CB(rcv_skb); |
| const u32 dccp_hdr_reset_len = sizeof(struct dccp_hdr) + |
| sizeof(struct dccp_hdr_ext) + |
| sizeof(struct dccp_hdr_reset); |
| struct dccp_hdr_reset *dhr; |
| struct sk_buff *skb; |
| |
| skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC); |
| if (skb == NULL) |
| return NULL; |
| |
| skb_reserve(skb, sk->sk_prot->max_header); |
| |
| /* Swap the send and the receive. */ |
| dh = dccp_zeroed_hdr(skb, dccp_hdr_reset_len); |
| dh->dccph_type = DCCP_PKT_RESET; |
| dh->dccph_sport = rxdh->dccph_dport; |
| dh->dccph_dport = rxdh->dccph_sport; |
| dh->dccph_doff = dccp_hdr_reset_len / 4; |
| dh->dccph_x = 1; |
| |
| dhr = dccp_hdr_reset(skb); |
| dhr->dccph_reset_code = dcb->dccpd_reset_code; |
| |
| switch (dcb->dccpd_reset_code) { |
| case DCCP_RESET_CODE_PACKET_ERROR: |
| dhr->dccph_reset_data[0] = rxdh->dccph_type; |
| break; |
| case DCCP_RESET_CODE_OPTION_ERROR: /* fall through */ |
| case DCCP_RESET_CODE_MANDATORY_ERROR: |
| memcpy(dhr->dccph_reset_data, dcb->dccpd_reset_data, 3); |
| break; |
| } |
| /* |
| * From RFC 4340, 8.3.1: |
| * If P.ackno exists, set R.seqno := P.ackno + 1. |
| * Else set R.seqno := 0. |
| */ |
| if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ) |
| dccp_hdr_set_seq(dh, ADD48(dcb->dccpd_ack_seq, 1)); |
| dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dcb->dccpd_seq); |
| |
| dccp_csum_outgoing(skb); |
| return skb; |
| } |
| |
| EXPORT_SYMBOL_GPL(dccp_ctl_make_reset); |
| |
| /* send Reset on established socket, to close or abort the connection */ |
| int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code) |
| { |
| struct sk_buff *skb; |
| /* |
| * FIXME: what if rebuild_header fails? |
| * Should we be doing a rebuild_header here? |
| */ |
| int err = inet_csk(sk)->icsk_af_ops->rebuild_header(sk); |
| |
| if (err != 0) |
| return err; |
| |
| skb = sock_wmalloc(sk, sk->sk_prot->max_header, 1, GFP_ATOMIC); |
| if (skb == NULL) |
| return -ENOBUFS; |
| |
| /* Reserve space for headers and prepare control bits. */ |
| skb_reserve(skb, sk->sk_prot->max_header); |
| DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET; |
| DCCP_SKB_CB(skb)->dccpd_reset_code = code; |
| |
| return dccp_transmit_skb(sk, skb); |
| } |
| |
| /* |
| * Do all connect socket setups that can be done AF independent. |
| */ |
| static inline void dccp_connect_init(struct sock *sk) |
| { |
| struct dccp_sock *dp = dccp_sk(sk); |
| struct dst_entry *dst = __sk_dst_get(sk); |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| |
| sk->sk_err = 0; |
| sock_reset_flag(sk, SOCK_DONE); |
| |
| dccp_sync_mss(sk, dst_mtu(dst)); |
| |
| /* Initialise GAR as per 8.5; AWL/AWH are set in dccp_transmit_skb() */ |
| dp->dccps_gar = dp->dccps_iss; |
| |
| icsk->icsk_retransmits = 0; |
| } |
| |
| int dccp_connect(struct sock *sk) |
| { |
| struct sk_buff *skb; |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| |
| /* do not connect if feature negotiation setup fails */ |
| if (dccp_feat_finalise_settings(dccp_sk(sk))) |
| return -EPROTO; |
| |
| dccp_connect_init(sk); |
| |
| skb = alloc_skb(sk->sk_prot->max_header, sk->sk_allocation); |
| if (unlikely(skb == NULL)) |
| return -ENOBUFS; |
| |
| /* Reserve space for headers. */ |
| skb_reserve(skb, sk->sk_prot->max_header); |
| |
| DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST; |
| |
| dccp_skb_entail(sk, skb); |
| dccp_transmit_skb(sk, skb_clone(skb, GFP_KERNEL)); |
| DCCP_INC_STATS(DCCP_MIB_ACTIVEOPENS); |
| |
| /* Timer for repeating the REQUEST until an answer. */ |
| inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
| icsk->icsk_rto, DCCP_RTO_MAX); |
| return 0; |
| } |
| |
| EXPORT_SYMBOL_GPL(dccp_connect); |
| |
| void dccp_send_ack(struct sock *sk) |
| { |
| /* If we have been reset, we may not send again. */ |
| if (sk->sk_state != DCCP_CLOSED) { |
| struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, |
| GFP_ATOMIC); |
| |
| if (skb == NULL) { |
| inet_csk_schedule_ack(sk); |
| inet_csk(sk)->icsk_ack.ato = TCP_ATO_MIN; |
| inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, |
| TCP_DELACK_MAX, |
| DCCP_RTO_MAX); |
| return; |
| } |
| |
| /* Reserve space for headers */ |
| skb_reserve(skb, sk->sk_prot->max_header); |
| DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK; |
| dccp_transmit_skb(sk, skb); |
| } |
| } |
| |
| EXPORT_SYMBOL_GPL(dccp_send_ack); |
| |
| #if 0 |
| /* FIXME: Is this still necessary (11.3) - currently nowhere used by DCCP. */ |
| void dccp_send_delayed_ack(struct sock *sk) |
| { |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| /* |
| * FIXME: tune this timer. elapsed time fixes the skew, so no problem |
| * with using 2s, and active senders also piggyback the ACK into a |
| * DATAACK packet, so this is really for quiescent senders. |
| */ |
| unsigned long timeout = jiffies + 2 * HZ; |
| |
| /* Use new timeout only if there wasn't a older one earlier. */ |
| if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) { |
| /* If delack timer was blocked or is about to expire, |
| * send ACK now. |
| * |
| * FIXME: check the "about to expire" part |
| */ |
| if (icsk->icsk_ack.blocked) { |
| dccp_send_ack(sk); |
| return; |
| } |
| |
| if (!time_before(timeout, icsk->icsk_ack.timeout)) |
| timeout = icsk->icsk_ack.timeout; |
| } |
| icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER; |
| icsk->icsk_ack.timeout = timeout; |
| sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout); |
| } |
| #endif |
| |
| void dccp_send_sync(struct sock *sk, const u64 ackno, |
| const enum dccp_pkt_type pkt_type) |
| { |
| /* |
| * We are not putting this on the write queue, so |
| * dccp_transmit_skb() will set the ownership to this |
| * sock. |
| */ |
| struct sk_buff *skb = alloc_skb(sk->sk_prot->max_header, GFP_ATOMIC); |
| |
| if (skb == NULL) { |
| /* FIXME: how to make sure the sync is sent? */ |
| DCCP_CRIT("could not send %s", dccp_packet_name(pkt_type)); |
| return; |
| } |
| |
| /* Reserve space for headers and prepare control bits. */ |
| skb_reserve(skb, sk->sk_prot->max_header); |
| DCCP_SKB_CB(skb)->dccpd_type = pkt_type; |
| DCCP_SKB_CB(skb)->dccpd_ack_seq = ackno; |
| |
| dccp_transmit_skb(sk, skb); |
| } |
| |
| EXPORT_SYMBOL_GPL(dccp_send_sync); |
| |
| /* |
| * Send a DCCP_PKT_CLOSE/CLOSEREQ. The caller locks the socket for us. This |
| * cannot be allowed to fail queueing a DCCP_PKT_CLOSE/CLOSEREQ frame under |
| * any circumstances. |
| */ |
| void dccp_send_close(struct sock *sk, const int active) |
| { |
| struct dccp_sock *dp = dccp_sk(sk); |
| struct sk_buff *skb; |
| const gfp_t prio = active ? GFP_KERNEL : GFP_ATOMIC; |
| |
| skb = alloc_skb(sk->sk_prot->max_header, prio); |
| if (skb == NULL) |
| return; |
| |
| /* Reserve space for headers and prepare control bits. */ |
| skb_reserve(skb, sk->sk_prot->max_header); |
| if (dp->dccps_role == DCCP_ROLE_SERVER && !dp->dccps_server_timewait) |
| DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSEREQ; |
| else |
| DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_CLOSE; |
| |
| if (active) { |
| dccp_write_xmit(sk, 1); |
| dccp_skb_entail(sk, skb); |
| dccp_transmit_skb(sk, skb_clone(skb, prio)); |
| /* |
| * Retransmission timer for active-close: RFC 4340, 8.3 requires |
| * to retransmit the Close/CloseReq until the CLOSING/CLOSEREQ |
| * state can be left. The initial timeout is 2 RTTs. |
| * Since RTT measurement is done by the CCIDs, there is no easy |
| * way to get an RTT sample. The fallback RTT from RFC 4340, 3.4 |
| * is too low (200ms); we use a high value to avoid unnecessary |
| * retransmissions when the link RTT is > 0.2 seconds. |
| * FIXME: Let main module sample RTTs and use that instead. |
| */ |
| inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
| DCCP_TIMEOUT_INIT, DCCP_RTO_MAX); |
| } else |
| dccp_transmit_skb(sk, skb); |
| } |