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authorArnaldo Carvalho de Melo <acme@ghostprotocols.net>2005-08-09 20:14:34 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2005-08-29 15:49:46 -0700
commit7c657876b63cb1d8a2ec06f8fc6c37bb8412e66c (patch)
tree3cb2732870c9cf8f976cb6fa57e0223f1c648e2a /net/dccp/output.c
parentc4365c9235f80128c3c3d5993074173941b1c1f0 (diff)
downloadlinux-linaro-7c657876b63cb1d8a2ec06f8fc6c37bb8412e66c.tar.gz
[DCCP]: Initial implementation
Development to this point was done on a subversion repository at: http://oops.ghostprotocols.net:81/cgi-bin/viewcvs.cgi/dccp-2.6/ This repository will be kept at this site for the foreseable future, so that interested parties can see the history of this code, attributions, etc. If I ever decide to take this offline I'll provide the full history at some other suitable place. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp/output.c')
-rw-r--r--net/dccp/output.c406
1 files changed, 406 insertions, 0 deletions
diff --git a/net/dccp/output.c b/net/dccp/output.c
new file mode 100644
index 00000000000..22ca2910d4f
--- /dev/null
+++ b/net/dccp/output.c
@@ -0,0 +1,406 @@
+/*
+ * 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/skbuff.h>
+
+#include <net/sock.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);
+}
+
+/*
+ * 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.
+ */
+int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
+{
+ if (likely(skb != NULL)) {
+ const struct inet_sock *inet = inet_sk(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 int 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;
+
+ /*
+ * FIXME: study DCCP_PKT_SYNC[ACK] to see what is the right thing
+ * to do here...
+ */
+ dccp_inc_seqno(&dp->dccps_gss);
+
+ dcb->dccpd_seq = dp->dccps_gss;
+ dccp_insert_options(sk, skb);
+
+ switch (dcb->dccpd_type) {
+ case DCCP_PKT_DATA:
+ set_ack = 0;
+ break;
+ case DCCP_PKT_SYNC:
+ case DCCP_PKT_SYNCACK:
+ ackno = dcb->dccpd_seq;
+ break;
+ }
+
+ skb->h.raw = skb_push(skb, dccp_header_size);
+ dh = dccp_hdr(skb);
+ /* Data packets are not cloned as they are never retransmitted */
+ if (skb_cloned(skb))
+ skb_set_owner_w(skb, sk);
+
+ /* 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 = dcb->dccpd_service;
+ break;
+ case DCCP_PKT_RESET:
+ dccp_hdr_reset(skb)->dccph_reset_code = dcb->dccpd_reset_code;
+ break;
+ }
+
+ dh->dccph_checksum = dccp_v4_checksum(skb);
+
+ if (dcb->dccpd_type == DCCP_PKT_ACK ||
+ dcb->dccpd_type == DCCP_PKT_DATAACK)
+ dccp_event_ack_sent(sk);
+
+ DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
+
+ err = ip_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 dccp_sock *dp = dccp_sk(sk);
+ int mss_now;
+
+ /*
+ * FIXME: we really should be using the af_specific thing to support IPv6.
+ * mss_now = pmtu - tp->af_specific->net_header_len - sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext);
+ */
+ mss_now = pmtu - sizeof(struct iphdr) - sizeof(struct dccp_hdr) - sizeof(struct dccp_hdr_ext);
+
+ /* Now subtract optional transport overhead */
+ mss_now -= dp->dccps_ext_header_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 */
+ dp->dccps_pmtu_cookie = pmtu;
+ dp->dccps_mss_cache = mss_now;
+
+ return mss_now;
+}
+
+int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
+{
+ if (inet_sk_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;
+ const int dccp_header_size = sizeof(struct dccp_hdr) +
+ sizeof(struct dccp_hdr_ext) +
+ sizeof(struct dccp_hdr_response);
+ struct sk_buff *skb = sock_wmalloc(sk, MAX_HEADER + DCCP_MAX_OPT_LEN +
+ dccp_header_size, 1,
+ GFP_ATOMIC);
+ if (skb == NULL)
+ return NULL;
+
+ /* Reserve space for headers. */
+ skb_reserve(skb, MAX_HEADER + DCCP_MAX_OPT_LEN + dccp_header_size);
+
+ skb->dst = dst_clone(dst);
+ skb->csum = 0;
+
+ DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_RESPONSE;
+ DCCP_SKB_CB(skb)->dccpd_seq = dccp_rsk(req)->dreq_iss;
+ dccp_insert_options(sk, skb);
+
+ 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, dccp_rsk(req)->dreq_iss);
+ dccp_hdr_set_ack(dccp_hdr_ack_bits(skb), dccp_rsk(req)->dreq_isr);
+
+ dh->dccph_checksum = dccp_v4_checksum(skb);
+
+ DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
+ return skb;
+}
+
+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 int dccp_header_size = sizeof(struct dccp_hdr) +
+ sizeof(struct dccp_hdr_ext) +
+ sizeof(struct dccp_hdr_reset);
+ struct sk_buff *skb = sock_wmalloc(sk, MAX_HEADER + DCCP_MAX_OPT_LEN +
+ dccp_header_size, 1,
+ GFP_ATOMIC);
+ if (skb == NULL)
+ return NULL;
+
+ /* Reserve space for headers. */
+ skb_reserve(skb, MAX_HEADER + DCCP_MAX_OPT_LEN + dccp_header_size);
+
+ 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;
+ dccp_insert_options(sk, skb);
+
+ 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;
+
+ dh->dccph_checksum = dccp_v4_checksum(skb);
+
+ DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
+ return skb;
+}
+
+/*
+ * Do all connect socket setups that can be done AF independent.
+ */
+static inline void dccp_connect_init(struct sock *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));
+
+ /*
+ * FIXME: set dp->{dccps_swh,dccps_swl}, with
+ * something like dccp_inc_seq
+ */
+
+ 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(MAX_DCCP_HEADER + 15, sk->sk_allocation);
+ if (unlikely(skb == NULL))
+ return -ENOBUFS;
+
+ /* Reserve space for headers. */
+ skb_reserve(skb, MAX_DCCP_HEADER);
+
+ DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_REQUEST;
+ /* FIXME: set service to something meaningful, coming
+ * from userspace*/
+ DCCP_SKB_CB(skb)->dccpd_service = 0;
+ skb->csum = 0;
+ skb_set_owner_w(skb, sk);
+
+ BUG_TRAP(sk->sk_send_head == NULL);
+ sk->sk_send_head = 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, TCP_RTO_MAX);
+ return 0;
+}
+
+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(MAX_DCCP_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, TCP_RTO_MAX);
+ return;
+ }
+
+ /* Reserve space for headers */
+ skb_reserve(skb, MAX_DCCP_HEADER);
+ skb->csum = 0;
+ DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_ACK;
+ skb_set_owner_w(skb, sk);
+ 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, u64 seq)
+{
+ /*
+ * 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(MAX_DCCP_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, MAX_DCCP_HEADER);
+ skb->csum = 0;
+ DCCP_SKB_CB(skb)->dccpd_type = DCCP_PKT_SYNC;
+ DCCP_SKB_CB(skb)->dccpd_seq = seq;
+
+ skb_set_owner_w(skb, sk);
+ dccp_transmit_skb(sk, skb);
+}
+
+/* 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)
+{
+ struct dccp_sock *dp = dccp_sk(sk);
+ struct sk_buff *skb;
+
+ /* Socket is locked, keep trying until memory is available. */
+ for (;;) {
+ skb = alloc_skb(sk->sk_prot->max_header, GFP_KERNEL);
+ if (skb != NULL)
+ break;
+ yield();
+ }
+
+ /* 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;
+
+ skb_set_owner_w(skb, sk);
+ dccp_transmit_skb(sk, skb);
+
+ ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
+ ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
+}