/*
* Copyright (c) 2006, 2017 Oracle and/or its affiliates. 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 <linux/slab.h>
#include <net/tcp.h>
#include "rds.h"
#include "tcp.h"
static struct kmem_cache *rds_tcp_incoming_slab;
static void rds_tcp_inc_purge(struct rds_incoming *inc)
{
struct rds_tcp_incoming *tinc;
tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
rdsdebug("purging tinc %p inc %p\n", tinc, inc);
skb_queue_purge(&tinc->ti_skb_list);
}
void rds_tcp_inc_free(struct rds_incoming *inc)
{
struct rds_tcp_incoming *tinc;
tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
rds_tcp_inc_purge(inc);
rdsdebug("freeing tinc %p inc %p\n", tinc, inc);
kmem_cache_free(rds_tcp_incoming_slab, tinc);
}
/*
* this is pretty lame, but, whatever.
*/
int rds_tcp_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to)
{
struct rds_tcp_incoming *tinc;
struct sk_buff *skb;
int ret = 0;
if (!iov_iter_count(to))
goto out;
tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
skb_queue_walk(&tinc->ti_skb_list, skb) {
unsigned long to_copy, skb_off;
for (skb_off = 0; skb_off < skb->len; skb_off += to_copy) {
to_copy = iov_iter_count(to);
to_copy = min(to_copy, skb->len - skb_off);
if (skb_copy_datagram_iter(skb, skb_off, to, to_copy))
return -EFAULT;
rds_stats_add(s_copy_to_user, to_copy);
ret += to_copy;
if (!iov_iter_count(to))
goto out;
}
}
out:
return ret;
}
/*
* We have a series of skbs that have fragmented pieces of the congestion
* bitmap. They must add up to the exact size of the congestion bitmap. We
* use the skb helpers to copy those into the pages that make up the in-memory
* congestion bitmap for the remote address of this connection. We then tell
* the congestion core that the bitmap has been changed so that it can wake up
* sleepers.
*
* This is racing with sending paths which are using test_bit to see if the
* bitmap indicates that their recipient is congested.
*/
static void rds_tcp_cong_recv(struct rds_connection *conn,
struct rds_tcp_incoming *tinc)
{
struct sk_buff *skb;
unsigned int to_copy, skb_off;
unsigned int map_off;
unsigned int map_page;
struct rds_cong_map *map;
int ret;
/* catch completely corrupt packets */
if (be32_to_cpu(tinc->ti_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
return;
map_page = 0;
map_off = 0;
map = conn->c_fcong;
skb_queue_walk(&tinc->ti_skb_list, skb) {
skb_off = 0;
while (skb_off < skb->len) {
to_copy = min_t(unsigned int, PAGE_SIZE - map_off,
skb->len - skb_off);
BUG_ON(map_page >= RDS_CONG_MAP_PAGES);
/* only returns 0 or -error */
ret = skb_copy_bits(skb, skb_off,
(void *)map->m_page_addrs[map_page] + map_off,
to_copy);
BUG_ON(ret != 0);
skb_off += to_copy;
map_off += to_copy;
if (map_off == PAGE_SIZE) {
map_off = 0;
map_page++;
}
}
}
rds_cong_map_updated(map, ~(u64) 0);
}
struct rds_tcp_desc_arg {
struct rds_conn_path *conn_path;
gfp_t gfp;
};
static int rds_tcp_data_recv(read_descriptor_t *desc, struct sk_buff *skb,
unsigned int offset, size_t len)
{
struct rds_tcp_desc_arg *arg = desc->arg.data;
struct rds_conn_path *cp = arg->conn_path;
struct rds_tcp_connection *tc = cp->cp_transport_data;
struct rds_tcp_incoming *tinc = tc->t_tinc;
struct sk_buff *clone;
size_t left = len, to_copy;
rdsdebug("tcp data tc %p skb %p offset %u len %zu\n", tc, skb, offset,
len);
/*
* tcp_read_sock() interprets partial progress as an indication to stop
* processing.
*/
while (left) {
if (!tinc) {
tinc = kmem_cache_alloc(rds_tcp_incoming_slab,
arg->gfp);
if (!tinc) {
desc->error = -ENOMEM;
goto out;
}
tc->t_tinc = tinc;
rdsdebug("alloced tinc %p\n", tinc);
rds_inc_path_init(&tinc->ti_inc, cp,
&cp->cp_conn->c_faddr);
tinc->ti_inc.i_rx_lat_trace[RDS_MSG_RX_HDR] =
local_clock();
/*
* XXX * we might be able to use the __ variants when
* we've already serialized at a higher level.
*/
skb_queue_head_init(&tinc->ti_skb_list);
}
if (left && tc->t_tinc_hdr_rem) {
to_copy = min(tc->t_tinc_hdr_rem, left);
rdsdebug("copying %zu header from skb %p\n", to_copy,
skb);
skb_copy_bits(skb, offset,
(char *)&tinc->ti_inc.i_hdr +
sizeof(struct rds_header) -
tc->t_tinc_hdr_rem,
to_copy);
tc->t_tinc_hdr_rem -= to_copy;
left -= to_copy;
offset += to_copy;
if (tc->t_tinc_hdr_rem == 0) {
/* could be 0 for a 0 len message */
tc->t_tinc_data_rem =
be32_to_cpu(tinc->ti_inc.i_hdr.h_len);
tinc->ti_inc.i_rx_lat_trace[RDS_MSG_RX_START] =
local_clock();
}
}
if (left && tc->t_tinc_data_rem) {
to_copy = min(tc->t_tinc_data_rem, left);
clone = pskb_extract(skb, offset, to_copy, arg->gfp);
if (!clone) {
desc->error = -ENOMEM;
goto out;
}
skb_queue_tail(&tinc->ti_skb_list, clone);
rdsdebug("skb %p data %p len %d off %u to_copy %zu -> "
"clone %p data %p len %d\n",
skb, skb->data, skb->len, offset, to_copy,
clone, clone->data, clone->len);
tc->t_tinc_data_rem -= to_copy;
left -= to_copy;
offset += to_copy;
}
if (tc->t_tinc_hdr_rem == 0 && tc->t_tinc_data_rem == 0) {
struct rds_connection *conn = cp->cp_conn;
if (tinc->ti_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
rds_tcp_cong_recv(conn, tinc);
else
rds_recv_incoming(conn, &conn->c_faddr,
&conn->c_laddr,
&tinc->ti_inc,
arg->gfp);
tc->t_tinc_hdr_rem = sizeof(struct rds_header);
tc->t_tinc_data_rem = 0;
tc->t_tinc = NULL;
rds_inc_put(&tinc->ti_inc);
tinc = NULL;
}
}
out:
rdsdebug("returning len %zu left %zu skb len %d rx queue depth %d\n",
len, left, skb->len,
skb_queue_len(&tc->t_sock->sk->sk_receive_queue));
return len - left;
}
/* the caller has to hold the sock lock */
static int rds_tcp_read_sock(struct rds_conn_path *cp, gfp_t gfp)
{
struct rds_tcp_connection *tc = cp->cp_transport_data;
struct socket *sock = tc->t_sock;
read_descriptor_t desc;
struct rds_tcp_desc_arg arg;
/* It's like glib in the kernel! */
arg.conn_path = cp;
arg.gfp = gfp;
desc.arg.data = &arg;
desc.error = 0;
desc.count = 1; /* give more than one skb per call */
tcp_read_sock(sock->sk, &desc, rds_tcp_data_recv);
rdsdebug("tcp_read_sock for tc %p gfp 0x%x returned %d\n", tc, gfp,
desc.error);
return desc.error;
}
/*
* We hold the sock lock to serialize our rds_tcp_recv->tcp_read_sock from
* data_ready.
*
* if we fail to allocate we're in trouble.. blindly wait some time before
* trying again to see if the VM can free up something for us.
*/
int rds_tcp_recv_path(struct rds_conn_path *cp)
{
struct rds_tcp_connection *tc = cp->cp_transport_data;
struct socket *sock = tc->t_sock;
int ret = 0;
rdsdebug("recv worker path [%d] tc %p sock %p\n",
cp->cp_index, tc, sock);
lock_sock(sock->sk);
ret = rds_tcp_read_sock(cp, GFP_KERNEL);
release_sock(sock->sk);
return ret;
}
void rds_tcp_data_ready(struct sock *sk)
{
void (*ready)(struct sock *sk);
struct rds_conn_path *cp;
struct rds_tcp_connection *tc;
rdsdebug("data ready sk %p\n", sk);
read_lock_bh(&sk->sk_callback_lock);
cp = sk->sk_user_data;
if (!cp) { /* check for teardown race */
ready = sk->sk_data_ready;
goto out;
}
tc = cp->cp_transport_data;
ready = tc->t_orig_data_ready;
rds_tcp_stats_inc(s_tcp_data_ready_calls);
if (rds_tcp_read_sock(cp, GFP_ATOMIC) == -ENOMEM) {
rcu_read_lock();
if (!rds_destroy_pending(cp->cp_conn))
queue_delayed_work(rds_wq, &cp->cp_recv_w, 0);
rcu_read_unlock();
}
out:
read_unlock_bh(&sk->sk_callback_lock);
ready(sk);
}
int rds_tcp_recv_init(void)
{
rds_tcp_incoming_slab = kmem_cache_create("rds_tcp_incoming",
sizeof(struct rds_tcp_incoming),
0, 0, NULL);
if (!rds_tcp_incoming_slab)
return -ENOMEM;
return 0;
}
void rds_tcp_recv_exit(void)
{
kmem_cache_destroy(rds_tcp_incoming_slab);
}