--- /dev/null
+/*
+ * 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/config.h>
+#include <linux/dccp.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.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;
+
+ dccp_inc_seqno(&dp->dccps_gss);
+
+ switch (dcb->dccpd_type) {
+ case DCCP_PKT_DATA:
+ set_ack = 0;
+ /* fall through */
+ case DCCP_PKT_DATAACK:
+ break;
+
+ case DCCP_PKT_REQUEST:
+ set_ack = 0;
+ /* fall through */
+
+ case DCCP_PKT_SYNC:
+ case DCCP_PKT_SYNCACK:
+ ackno = dcb->dccpd_seq;
+ /* fall through */
+ default:
+ /*
+ * Only data packets should come through with skb->sk
+ * set.
+ */
+ WARN_ON(skb->sk);
+ skb_set_owner_w(skb, sk);
+ break;
+ }
+
+ dcb->dccpd_seq = dp->dccps_gss;
+
+ if (dccp_insert_options(sk, skb)) {
+ kfree_skb(skb);
+ return -EPROTO;
+ }
+
+ skb->h.raw = skb_push(skb, dccp_header_size);
+ dh = dccp_hdr(skb);
+
+ /* Build DCCP header and checksum it. */
+ memset(dh, 0, dccp_header_size);
+ dh->dccph_type = dcb->dccpd_type;
+ dh->dccph_sport = inet->sport;
+ dh->dccph_dport = inet->dport;
+ dh->dccph_doff = (dccp_header_size + dcb->dccpd_opt_len) / 4;
+ dh->dccph_ccval = dcb->dccpd_ccval;
+ /* XXX For now we're using only 48 bits sequence numbers */
+ dh->dccph_x = 1;
+
+ dp->dccps_awh = dp->dccps_gss;
+ 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;
+ 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->len, skb);
+
+ if (set_ack)
+ dccp_event_ack_sent(sk);
+
+ DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
+
+ memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+ err = icsk->icsk_af_ops->queue_xmit(skb, 0);
+ if (err <= 0)
+ return err;
+
+ /* NET_XMIT_CN is special. It does not guarantee,
+ * that this packet is lost. It tells that device
+ * is about to start to drop packets or already
+ * drops some packets of the same priority and
+ * invokes us to send less aggressively.
+ */
+ return err == NET_XMIT_CN ? 0 : err;
+ }
+ return -ENOBUFS;
+}
+
+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);
+ int mss_now = (pmtu - icsk->icsk_af_ops->net_header_len -
+ sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext));
+
+ /* Now subtract optional transport overhead */
+ mss_now -= icsk->icsk_ext_hdr_len;
+
+ /*
+ * FIXME: this should come from the CCID infrastructure, where, say,
+ * TFRC will say it wants TIMESTAMPS, ELAPSED time, etc, for now lets
+ * put a rough estimate for NDP + TIMESTAMP + TIMESTAMP_ECHO + ELAPSED
+ * TIME + TFRC_OPT_LOSS_EVENT_RATE + TFRC_OPT_RECEIVE_RATE + padding to
+ * make it a multiple of 4
+ */
+
+ mss_now -= ((5 + 6 + 10 + 6 + 6 + 6 + 3) / 4) * 4;
+
+ /* And store cached results */
+ icsk->icsk_pmtu_cookie = pmtu;
+ dp->dccps_mss_cache = mss_now;
+
+ return mss_now;
+}
+
+EXPORT_SYMBOL_GPL(dccp_sync_mss);
+
+void dccp_write_space(struct sock *sk)
+{
+ read_lock(&sk->sk_callback_lock);
+
+ if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
+ wake_up_interruptible(sk->sk_sleep);
+ /* Should agree with poll, otherwise some programs break */
+ if (sock_writeable(sk))
+ sk_wake_async(sk, 2, 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
+ * @timeo: for how long
+ */
+static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb,
+ long *timeo)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+ DEFINE_WAIT(wait);
+ long delay;
+ int rc;
+
+ while (1) {
+ prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
+
+ if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
+ goto do_error;
+ if (!*timeo)
+ goto do_nonblock;
+ if (signal_pending(current))
+ goto do_interrupted;
+
+ rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
+ skb->len);
+ if (rc <= 0)
+ break;
+ delay = msecs_to_jiffies(rc);
+ if (delay > *timeo || delay < 0)
+ goto do_nonblock;
+
+ sk->sk_write_pending++;
+ release_sock(sk);
+ *timeo -= schedule_timeout(delay);
+ lock_sock(sk);
+ sk->sk_write_pending--;
+ }
+out:
+ finish_wait(sk->sk_sleep, &wait);
+ return rc;
+
+do_error:
+ rc = -EPIPE;
+ goto out;
+do_nonblock:
+ rc = -EAGAIN;
+ goto out;
+do_interrupted:
+ rc = sock_intr_errno(*timeo);
+ goto out;
+}
+
+int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, long *timeo)
+{
+ const struct dccp_sock *dp = dccp_sk(sk);
+ int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,
+ skb->len);
+
+ if (err > 0)
+ err = dccp_wait_for_ccid(sk, skb, timeo);
+
+ if (err == 0) {
+ struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
+ const int len = skb->len;
+
+ if (sk->sk_state == DCCP_PARTOPEN) {
+ /* See 8.1.5. Handshake Completion */
+ 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);
+ } else
+ kfree_skb(skb);
+
+ return err;
+}
+
+int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
+{
+ 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)));
+}
+
+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 = dst_clone(dst);
+ skb->csum = 0;
+
+ dreq = dccp_rsk(req);
+ DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
+ DCCP_SKB_CB(skb)->dccpd_seq = dreq->dreq_iss;
+
+ if (dccp_insert_options(sk, skb)) {
+ kfree_skb(skb);
+ return NULL;
+ }
+
+ skb->h.raw = skb_push(skb, dccp_header_size);
+
+ dh = dccp_hdr(skb);
+ memset(dh, 0, dccp_header_size);
+
+ dh->dccph_sport = inet_sk(sk)->sport;
+ 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_INC_STATS(DCCP_MIB_OUTSEGS);
+ return skb;
+}
+
+EXPORT_SYMBOL_GPL(dccp_make_response);
+
+static struct sk_buff *dccp_make_reset(struct sock *sk, struct dst_entry *dst,
+ const enum dccp_reset_codes code)
+
+{
+ struct dccp_hdr *dh;
+ struct dccp_sock *dp = dccp_sk(sk);
+ const u32 dccp_header_size = sizeof(struct dccp_hdr) +
+ sizeof(struct dccp_hdr_ext) +
+ sizeof(struct dccp_hdr_reset);
+ 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 = dst_clone(dst);
+ skb->csum = 0;
+
+ dccp_inc_seqno(&dp->dccps_gss);
+
+ DCCP_SKB_CB(skb)->dccpd_reset_code = code;
+ DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESET;
+ DCCP_SKB_CB(skb)->dccpd_seq = dp->dccps_gss;
+
+ if (dccp_insert_options(sk, skb)) {
+ kfree_skb(skb);
+ return NULL;
+ }
+
+ skb->h.raw = skb_push(skb, dccp_header_size);
+
+ dh = dccp_hdr(skb);
+ memset(dh, 0, dccp_header_size);
+
+ dh->dccph_sport = inet_sk(sk)->sport;
+ dh->dccph_dport = inet_sk(sk)->dport;
+ dh->dccph_doff = (dccp_header_size +
+ DCCP_SKB_CB(skb)->dccpd_opt_len) / 4;
+ dh->dccph_type = DCCP_PKT_RESET;
+ dh->dccph_x = 1;
+ dccp_hdr_set_seq(dh, dp->dccps_gss);
+ dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dp->dccps_gsr);
+
+ dccp_hdr_reset(skb)->dccph_reset_code = code;
+ inet_csk(sk)->icsk_af_ops->send_check(sk, skb->len, skb);
+
+ DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
+ return skb;
+}
+
+int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code)
+{
+ /*
+ * FIXME: what if rebuild_header fails?
+ * Should we be doing a rebuild_header here?
+ */
+ int err = inet_sk_rebuild_header(sk);
+
+ if (err == 0) {
+ struct sk_buff *skb = dccp_make_reset(sk, sk->sk_dst_cache,
+ code);
+ if (skb != NULL) {
+ memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+ err = inet_csk(sk)->icsk_af_ops->queue_xmit(skb, 0);
+ if (err == NET_XMIT_CN)
+ err = 0;
+ }
+ }
+
+ return err;
+}
+
+/*
+ * 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));
+
+ dccp_update_gss(sk, dp->dccps_iss);
+ /*
+ * 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_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, 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);
+
+ 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;
+ skb->csum = 0;
+
+ 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);
+ skb->csum = 0;
+ DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
+ dccp_transmit_skb(sk, skb);
+ }
+}
+
+EXPORT_SYMBOL_GPL(dccp_send_ack);
+
+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);
+}
+
+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
+ * 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? */
+ return;
+
+ /* Reserve space for headers and prepare control bits. */
+ skb_reserve(skb, sk->sk_prot->max_header);
+ skb->csum = 0;
+ DCCP_SKB_CB(skb)->dccpd_type = pkt_type;
+ DCCP_SKB_CB(skb)->dccpd_seq = seq;
+
+ 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);
+ skb->csum = 0;
+ DCCP_SKB_CB(skb)->dccpd_type = dp->dccps_role == DCCP_ROLE_CLIENT ?
+ DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;
+
+ if (active) {
+ dccp_skb_entail(sk, skb);
+ dccp_transmit_skb(sk, skb_clone(skb, prio));
+ } else
+ dccp_transmit_skb(sk, skb);
+}
git://git.onelab.eu / linux-2.6.git / blobdiff