RDS: recv.c
Upon receiving a datagram from the transport, RDS parses the
headers and potentially queues an ACK.
Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rds/recv.c b/net/rds/recv.c
new file mode 100644
index 0000000..f2118c5
--- /dev/null
+++ b/net/rds/recv.c
@@ -0,0 +1,542 @@
+/*
+ * Copyright (c) 2006 Oracle. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses. You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials
+ * provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+#include <linux/kernel.h>
+#include <net/sock.h>
+#include <linux/in.h>
+
+#include "rds.h"
+#include "rdma.h"
+
+void rds_inc_init(struct rds_incoming *inc, struct rds_connection *conn,
+ __be32 saddr)
+{
+ atomic_set(&inc->i_refcount, 1);
+ INIT_LIST_HEAD(&inc->i_item);
+ inc->i_conn = conn;
+ inc->i_saddr = saddr;
+ inc->i_rdma_cookie = 0;
+}
+
+void rds_inc_addref(struct rds_incoming *inc)
+{
+ rdsdebug("addref inc %p ref %d\n", inc, atomic_read(&inc->i_refcount));
+ atomic_inc(&inc->i_refcount);
+}
+
+void rds_inc_put(struct rds_incoming *inc)
+{
+ rdsdebug("put inc %p ref %d\n", inc, atomic_read(&inc->i_refcount));
+ if (atomic_dec_and_test(&inc->i_refcount)) {
+ BUG_ON(!list_empty(&inc->i_item));
+
+ inc->i_conn->c_trans->inc_free(inc);
+ }
+}
+
+static void rds_recv_rcvbuf_delta(struct rds_sock *rs, struct sock *sk,
+ struct rds_cong_map *map,
+ int delta, __be16 port)
+{
+ int now_congested;
+
+ if (delta == 0)
+ return;
+
+ rs->rs_rcv_bytes += delta;
+ now_congested = rs->rs_rcv_bytes > rds_sk_rcvbuf(rs);
+
+ rdsdebug("rs %p (%pI4:%u) recv bytes %d buf %d "
+ "now_cong %d delta %d\n",
+ rs, &rs->rs_bound_addr,
+ ntohs(rs->rs_bound_port), rs->rs_rcv_bytes,
+ rds_sk_rcvbuf(rs), now_congested, delta);
+
+ /* wasn't -> am congested */
+ if (!rs->rs_congested && now_congested) {
+ rs->rs_congested = 1;
+ rds_cong_set_bit(map, port);
+ rds_cong_queue_updates(map);
+ }
+ /* was -> aren't congested */
+ /* Require more free space before reporting uncongested to prevent
+ bouncing cong/uncong state too often */
+ else if (rs->rs_congested && (rs->rs_rcv_bytes < (rds_sk_rcvbuf(rs)/2))) {
+ rs->rs_congested = 0;
+ rds_cong_clear_bit(map, port);
+ rds_cong_queue_updates(map);
+ }
+
+ /* do nothing if no change in cong state */
+}
+
+/*
+ * Process all extension headers that come with this message.
+ */
+static void rds_recv_incoming_exthdrs(struct rds_incoming *inc, struct rds_sock *rs)
+{
+ struct rds_header *hdr = &inc->i_hdr;
+ unsigned int pos = 0, type, len;
+ union {
+ struct rds_ext_header_version version;
+ struct rds_ext_header_rdma rdma;
+ struct rds_ext_header_rdma_dest rdma_dest;
+ } buffer;
+
+ while (1) {
+ len = sizeof(buffer);
+ type = rds_message_next_extension(hdr, &pos, &buffer, &len);
+ if (type == RDS_EXTHDR_NONE)
+ break;
+ /* Process extension header here */
+ switch (type) {
+ case RDS_EXTHDR_RDMA:
+ rds_rdma_unuse(rs, be32_to_cpu(buffer.rdma.h_rdma_rkey), 0);
+ break;
+
+ case RDS_EXTHDR_RDMA_DEST:
+ /* We ignore the size for now. We could stash it
+ * somewhere and use it for error checking. */
+ inc->i_rdma_cookie = rds_rdma_make_cookie(
+ be32_to_cpu(buffer.rdma_dest.h_rdma_rkey),
+ be32_to_cpu(buffer.rdma_dest.h_rdma_offset));
+
+ break;
+ }
+ }
+}
+
+/*
+ * The transport must make sure that this is serialized against other
+ * rx and conn reset on this specific conn.
+ *
+ * We currently assert that only one fragmented message will be sent
+ * down a connection at a time. This lets us reassemble in the conn
+ * instead of per-flow which means that we don't have to go digging through
+ * flows to tear down partial reassembly progress on conn failure and
+ * we save flow lookup and locking for each frag arrival. It does mean
+ * that small messages will wait behind large ones. Fragmenting at all
+ * is only to reduce the memory consumption of pre-posted buffers.
+ *
+ * The caller passes in saddr and daddr instead of us getting it from the
+ * conn. This lets loopback, who only has one conn for both directions,
+ * tell us which roles the addrs in the conn are playing for this message.
+ */
+void rds_recv_incoming(struct rds_connection *conn, __be32 saddr, __be32 daddr,
+ struct rds_incoming *inc, gfp_t gfp, enum km_type km)
+{
+ struct rds_sock *rs = NULL;
+ struct sock *sk;
+ unsigned long flags;
+
+ inc->i_conn = conn;
+ inc->i_rx_jiffies = jiffies;
+
+ rdsdebug("conn %p next %llu inc %p seq %llu len %u sport %u dport %u "
+ "flags 0x%x rx_jiffies %lu\n", conn,
+ (unsigned long long)conn->c_next_rx_seq,
+ inc,
+ (unsigned long long)be64_to_cpu(inc->i_hdr.h_sequence),
+ be32_to_cpu(inc->i_hdr.h_len),
+ be16_to_cpu(inc->i_hdr.h_sport),
+ be16_to_cpu(inc->i_hdr.h_dport),
+ inc->i_hdr.h_flags,
+ inc->i_rx_jiffies);
+
+ /*
+ * Sequence numbers should only increase. Messages get their
+ * sequence number as they're queued in a sending conn. They
+ * can be dropped, though, if the sending socket is closed before
+ * they hit the wire. So sequence numbers can skip forward
+ * under normal operation. They can also drop back in the conn
+ * failover case as previously sent messages are resent down the
+ * new instance of a conn. We drop those, otherwise we have
+ * to assume that the next valid seq does not come after a
+ * hole in the fragment stream.
+ *
+ * The headers don't give us a way to realize if fragments of
+ * a message have been dropped. We assume that frags that arrive
+ * to a flow are part of the current message on the flow that is
+ * being reassembled. This means that senders can't drop messages
+ * from the sending conn until all their frags are sent.
+ *
+ * XXX we could spend more on the wire to get more robust failure
+ * detection, arguably worth it to avoid data corruption.
+ */
+ if (be64_to_cpu(inc->i_hdr.h_sequence) < conn->c_next_rx_seq
+ && (inc->i_hdr.h_flags & RDS_FLAG_RETRANSMITTED)) {
+ rds_stats_inc(s_recv_drop_old_seq);
+ goto out;
+ }
+ conn->c_next_rx_seq = be64_to_cpu(inc->i_hdr.h_sequence) + 1;
+
+ if (rds_sysctl_ping_enable && inc->i_hdr.h_dport == 0) {
+ rds_stats_inc(s_recv_ping);
+ rds_send_pong(conn, inc->i_hdr.h_sport);
+ goto out;
+ }
+
+ rs = rds_find_bound(daddr, inc->i_hdr.h_dport);
+ if (rs == NULL) {
+ rds_stats_inc(s_recv_drop_no_sock);
+ goto out;
+ }
+
+ /* Process extension headers */
+ rds_recv_incoming_exthdrs(inc, rs);
+
+ /* We can be racing with rds_release() which marks the socket dead. */
+ sk = rds_rs_to_sk(rs);
+
+ /* serialize with rds_release -> sock_orphan */
+ write_lock_irqsave(&rs->rs_recv_lock, flags);
+ if (!sock_flag(sk, SOCK_DEAD)) {
+ rdsdebug("adding inc %p to rs %p's recv queue\n", inc, rs);
+ rds_stats_inc(s_recv_queued);
+ rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
+ be32_to_cpu(inc->i_hdr.h_len),
+ inc->i_hdr.h_dport);
+ rds_inc_addref(inc);
+ list_add_tail(&inc->i_item, &rs->rs_recv_queue);
+ __rds_wake_sk_sleep(sk);
+ } else {
+ rds_stats_inc(s_recv_drop_dead_sock);
+ }
+ write_unlock_irqrestore(&rs->rs_recv_lock, flags);
+
+out:
+ if (rs)
+ rds_sock_put(rs);
+}
+
+/*
+ * be very careful here. This is being called as the condition in
+ * wait_event_*() needs to cope with being called many times.
+ */
+static int rds_next_incoming(struct rds_sock *rs, struct rds_incoming **inc)
+{
+ unsigned long flags;
+
+ if (*inc == NULL) {
+ read_lock_irqsave(&rs->rs_recv_lock, flags);
+ if (!list_empty(&rs->rs_recv_queue)) {
+ *inc = list_entry(rs->rs_recv_queue.next,
+ struct rds_incoming,
+ i_item);
+ rds_inc_addref(*inc);
+ }
+ read_unlock_irqrestore(&rs->rs_recv_lock, flags);
+ }
+
+ return *inc != NULL;
+}
+
+static int rds_still_queued(struct rds_sock *rs, struct rds_incoming *inc,
+ int drop)
+{
+ struct sock *sk = rds_rs_to_sk(rs);
+ int ret = 0;
+ unsigned long flags;
+
+ write_lock_irqsave(&rs->rs_recv_lock, flags);
+ if (!list_empty(&inc->i_item)) {
+ ret = 1;
+ if (drop) {
+ /* XXX make sure this i_conn is reliable */
+ rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
+ -be32_to_cpu(inc->i_hdr.h_len),
+ inc->i_hdr.h_dport);
+ list_del_init(&inc->i_item);
+ rds_inc_put(inc);
+ }
+ }
+ write_unlock_irqrestore(&rs->rs_recv_lock, flags);
+
+ rdsdebug("inc %p rs %p still %d dropped %d\n", inc, rs, ret, drop);
+ return ret;
+}
+
+/*
+ * Pull errors off the error queue.
+ * If msghdr is NULL, we will just purge the error queue.
+ */
+int rds_notify_queue_get(struct rds_sock *rs, struct msghdr *msghdr)
+{
+ struct rds_notifier *notifier;
+ struct rds_rdma_notify cmsg;
+ unsigned int count = 0, max_messages = ~0U;
+ unsigned long flags;
+ LIST_HEAD(copy);
+ int err = 0;
+
+
+ /* put_cmsg copies to user space and thus may sleep. We can't do this
+ * with rs_lock held, so first grab as many notifications as we can stuff
+ * in the user provided cmsg buffer. We don't try to copy more, to avoid
+ * losing notifications - except when the buffer is so small that it wouldn't
+ * even hold a single notification. Then we give him as much of this single
+ * msg as we can squeeze in, and set MSG_CTRUNC.
+ */
+ if (msghdr) {
+ max_messages = msghdr->msg_controllen / CMSG_SPACE(sizeof(cmsg));
+ if (!max_messages)
+ max_messages = 1;
+ }
+
+ spin_lock_irqsave(&rs->rs_lock, flags);
+ while (!list_empty(&rs->rs_notify_queue) && count < max_messages) {
+ notifier = list_entry(rs->rs_notify_queue.next,
+ struct rds_notifier, n_list);
+ list_move(¬ifier->n_list, ©);
+ count++;
+ }
+ spin_unlock_irqrestore(&rs->rs_lock, flags);
+
+ if (!count)
+ return 0;
+
+ while (!list_empty(©)) {
+ notifier = list_entry(copy.next, struct rds_notifier, n_list);
+
+ if (msghdr) {
+ cmsg.user_token = notifier->n_user_token;
+ cmsg.status = notifier->n_status;
+
+ err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_RDMA_STATUS,
+ sizeof(cmsg), &cmsg);
+ if (err)
+ break;
+ }
+
+ list_del_init(¬ifier->n_list);
+ kfree(notifier);
+ }
+
+ /* If we bailed out because of an error in put_cmsg,
+ * we may be left with one or more notifications that we
+ * didn't process. Return them to the head of the list. */
+ if (!list_empty(©)) {
+ spin_lock_irqsave(&rs->rs_lock, flags);
+ list_splice(©, &rs->rs_notify_queue);
+ spin_unlock_irqrestore(&rs->rs_lock, flags);
+ }
+
+ return err;
+}
+
+/*
+ * Queue a congestion notification
+ */
+static int rds_notify_cong(struct rds_sock *rs, struct msghdr *msghdr)
+{
+ uint64_t notify = rs->rs_cong_notify;
+ unsigned long flags;
+ int err;
+
+ err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_CONG_UPDATE,
+ sizeof(notify), ¬ify);
+ if (err)
+ return err;
+
+ spin_lock_irqsave(&rs->rs_lock, flags);
+ rs->rs_cong_notify &= ~notify;
+ spin_unlock_irqrestore(&rs->rs_lock, flags);
+
+ return 0;
+}
+
+/*
+ * Receive any control messages.
+ */
+static int rds_cmsg_recv(struct rds_incoming *inc, struct msghdr *msg)
+{
+ int ret = 0;
+
+ if (inc->i_rdma_cookie) {
+ ret = put_cmsg(msg, SOL_RDS, RDS_CMSG_RDMA_DEST,
+ sizeof(inc->i_rdma_cookie), &inc->i_rdma_cookie);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+int rds_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
+ size_t size, int msg_flags)
+{
+ struct sock *sk = sock->sk;
+ struct rds_sock *rs = rds_sk_to_rs(sk);
+ long timeo;
+ int ret = 0, nonblock = msg_flags & MSG_DONTWAIT;
+ struct sockaddr_in *sin;
+ struct rds_incoming *inc = NULL;
+
+ /* udp_recvmsg()->sock_recvtimeo() gets away without locking too.. */
+ timeo = sock_rcvtimeo(sk, nonblock);
+
+ rdsdebug("size %zu flags 0x%x timeo %ld\n", size, msg_flags, timeo);
+
+ if (msg_flags & MSG_OOB)
+ goto out;
+
+ /* If there are pending notifications, do those - and nothing else */
+ if (!list_empty(&rs->rs_notify_queue)) {
+ ret = rds_notify_queue_get(rs, msg);
+ goto out;
+ }
+
+ if (rs->rs_cong_notify) {
+ ret = rds_notify_cong(rs, msg);
+ goto out;
+ }
+
+ while (1) {
+ if (!rds_next_incoming(rs, &inc)) {
+ if (nonblock) {
+ ret = -EAGAIN;
+ break;
+ }
+
+ timeo = wait_event_interruptible_timeout(*sk->sk_sleep,
+ rds_next_incoming(rs, &inc),
+ timeo);
+ rdsdebug("recvmsg woke inc %p timeo %ld\n", inc,
+ timeo);
+ if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
+ continue;
+
+ ret = timeo;
+ if (ret == 0)
+ ret = -ETIMEDOUT;
+ break;
+ }
+
+ rdsdebug("copying inc %p from %pI4:%u to user\n", inc,
+ &inc->i_conn->c_faddr,
+ ntohs(inc->i_hdr.h_sport));
+ ret = inc->i_conn->c_trans->inc_copy_to_user(inc, msg->msg_iov,
+ size);
+ if (ret < 0)
+ break;
+
+ /*
+ * if the message we just copied isn't at the head of the
+ * recv queue then someone else raced us to return it, try
+ * to get the next message.
+ */
+ if (!rds_still_queued(rs, inc, !(msg_flags & MSG_PEEK))) {
+ rds_inc_put(inc);
+ inc = NULL;
+ rds_stats_inc(s_recv_deliver_raced);
+ continue;
+ }
+
+ if (ret < be32_to_cpu(inc->i_hdr.h_len)) {
+ if (msg_flags & MSG_TRUNC)
+ ret = be32_to_cpu(inc->i_hdr.h_len);
+ msg->msg_flags |= MSG_TRUNC;
+ }
+
+ if (rds_cmsg_recv(inc, msg)) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ rds_stats_inc(s_recv_delivered);
+
+ sin = (struct sockaddr_in *)msg->msg_name;
+ if (sin) {
+ sin->sin_family = AF_INET;
+ sin->sin_port = inc->i_hdr.h_sport;
+ sin->sin_addr.s_addr = inc->i_saddr;
+ memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
+ }
+ break;
+ }
+
+ if (inc)
+ rds_inc_put(inc);
+
+out:
+ return ret;
+}
+
+/*
+ * The socket is being shut down and we're asked to drop messages that were
+ * queued for recvmsg. The caller has unbound the socket so the receive path
+ * won't queue any more incoming fragments or messages on the socket.
+ */
+void rds_clear_recv_queue(struct rds_sock *rs)
+{
+ struct sock *sk = rds_rs_to_sk(rs);
+ struct rds_incoming *inc, *tmp;
+ unsigned long flags;
+
+ write_lock_irqsave(&rs->rs_recv_lock, flags);
+ list_for_each_entry_safe(inc, tmp, &rs->rs_recv_queue, i_item) {
+ rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
+ -be32_to_cpu(inc->i_hdr.h_len),
+ inc->i_hdr.h_dport);
+ list_del_init(&inc->i_item);
+ rds_inc_put(inc);
+ }
+ write_unlock_irqrestore(&rs->rs_recv_lock, flags);
+}
+
+/*
+ * inc->i_saddr isn't used here because it is only set in the receive
+ * path.
+ */
+void rds_inc_info_copy(struct rds_incoming *inc,
+ struct rds_info_iterator *iter,
+ __be32 saddr, __be32 daddr, int flip)
+{
+ struct rds_info_message minfo;
+
+ minfo.seq = be64_to_cpu(inc->i_hdr.h_sequence);
+ minfo.len = be32_to_cpu(inc->i_hdr.h_len);
+
+ if (flip) {
+ minfo.laddr = daddr;
+ minfo.faddr = saddr;
+ minfo.lport = inc->i_hdr.h_dport;
+ minfo.fport = inc->i_hdr.h_sport;
+ } else {
+ minfo.laddr = saddr;
+ minfo.faddr = daddr;
+ minfo.lport = inc->i_hdr.h_sport;
+ minfo.fport = inc->i_hdr.h_dport;
+ }
+
+ rds_info_copy(iter, &minfo, sizeof(minfo));
+}
