Release 4.11 net/sunrpc/xprtsock.c

/*
 * linux/net/sunrpc/xprtsock.c
 *
 * Client-side transport implementation for sockets.
 *
 * TCP callback races fixes (C) 1998 Red Hat
 * TCP send fixes (C) 1998 Red Hat
 * TCP NFS related read + write fixes
 *  (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
 *
 * Rewrite of larges part of the code in order to stabilize TCP stuff.
 * Fix behaviour when socket buffer is full.
 *  (C) 1999 Trond Myklebust <trond.myklebust@fys.uio.no>
 *
 * IP socket transport implementation, (C) 2005 Chuck Lever <cel@netapp.com>
 *
 * IPv6 support contributed by Gilles Quillard, Bull Open Source, 2005.
 *   <gilles.quillard@bull.net>
 */

#include <linux/types.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/capability.h>
#include <linux/pagemap.h>
#include <linux/errno.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/net.h>
#include <linux/mm.h>
#include <linux/un.h>
#include <linux/udp.h>
#include <linux/tcp.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/addr.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/xprtsock.h>
#include <linux/file.h>
#ifdef CONFIG_SUNRPC_BACKCHANNEL
#include <linux/sunrpc/bc_xprt.h>
#endif

#include <net/sock.h>
#include <net/checksum.h>
#include <net/udp.h>
#include <net/tcp.h>

#include <trace/events/sunrpc.h>

#include "sunrpc.h"

static void xs_close(struct rpc_xprt *xprt);
static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
		struct socket *sock);

/*
 * xprtsock tunables
 */

static unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;

static unsigned int xprt_tcp_slot_table_entries = RPC_MIN_SLOT_TABLE;

static unsigned int xprt_max_tcp_slot_table_entries = RPC_MAX_SLOT_TABLE;


static unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;

static unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;

#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)


#define XS_TCP_LINGER_TO	(15U * HZ)

static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;

/*
 * We can register our own files under /proc/sys/sunrpc by
 * calling register_sysctl_table() again.  The files in that
 * directory become the union of all files registered there.
 *
 * We simply need to make sure that we don't collide with
 * someone else's file names!
 */


static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;

static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;

static unsigned int max_tcp_slot_table_limit = RPC_MAX_SLOT_TABLE_LIMIT;

static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;

static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;


static struct ctl_table_header *sunrpc_table_header;

/*
 * FIXME: changing the UDP slot table size should also resize the UDP
 *        socket buffers for existing UDP transports
 */

static struct ctl_table xs_tunables_table[] = {
	{
		.procname	= "udp_slot_table_entries",
		.data		= &xprt_udp_slot_table_entries,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= &min_slot_table_size,
		.extra2		= &max_slot_table_size
	},
	{
		.procname	= "tcp_slot_table_entries",
		.data		= &xprt_tcp_slot_table_entries,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= &min_slot_table_size,
		.extra2		= &max_slot_table_size
	},
	{
		.procname	= "tcp_max_slot_table_entries",
		.data		= &xprt_max_tcp_slot_table_entries,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= &min_slot_table_size,
		.extra2		= &max_tcp_slot_table_limit
	},
	{
		.procname	= "min_resvport",
		.data		= &xprt_min_resvport,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= &xprt_min_resvport_limit,
		.extra2		= &xprt_max_resvport
	},
	{
		.procname	= "max_resvport",
		.data		= &xprt_max_resvport,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= &xprt_min_resvport,
		.extra2		= &xprt_max_resvport_limit
	},
	{
		.procname	= "tcp_fin_timeout",
		.data		= &xs_tcp_fin_timeout,
		.maxlen		= sizeof(xs_tcp_fin_timeout),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_jiffies,
        },
	{ },
};


static struct ctl_table sunrpc_table[] = {
	{
		.procname	= "sunrpc",
		.mode		= 0555,
		.child		= xs_tunables_table
	},
	{ },
};

#endif

/*
 * Wait duration for a reply from the RPC portmapper.
 */

#define XS_BIND_TO		(60U * HZ)

/*
 * Delay if a UDP socket connect error occurs.  This is most likely some
 * kind of resource problem on the local host.
 */

#define XS_UDP_REEST_TO		(2U * HZ)

/*
 * The reestablish timeout allows clients to delay for a bit before attempting
 * to reconnect to a server that just dropped our connection.
 *
 * We implement an exponential backoff when trying to reestablish a TCP
 * transport connection with the server.  Some servers like to drop a TCP
 * connection when they are overworked, so we start with a short timeout and
 * increase over time if the server is down or not responding.
 */

#define XS_TCP_INIT_REEST_TO	(3U * HZ)

/*
 * TCP idle timeout; client drops the transport socket if it is idle
 * for this long.  Note that we also timeout UDP sockets to prevent
 * holding port numbers when there is no RPC traffic.
 */

#define XS_IDLE_DISC_TO		(5U * 60 * HZ)

#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)

# undef  RPC_DEBUG_DATA

# define RPCDBG_FACILITY	RPCDBG_TRANS
#endif

#ifdef RPC_DEBUG_DATA


static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
{
	u8 *buf = (u8 *) packet;
	int j;

	dprintk("RPC:       %s\n", msg);
	for (j = 0; j < count && j < 128; j += 4) {
		if (!(j & 31)) {
			if (j)
				dprintk("\n");
			dprintk("0x%04x ", j);
		}
		dprintk("%02x%02x%02x%02x ",
			buf[j], buf[j+1], buf[j+2], buf[j+3]);
	}
	dprintk("\n");
}
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#else


static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
{
	/* NOP */
}
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#endif



static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
{
	return (struct rpc_xprt *) sk->sk_user_data;
}

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static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
{
	return (struct sockaddr *) &xprt->addr;
}

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static inline struct sockaddr_un *xs_addr_un(struct rpc_xprt *xprt)
{
	return (struct sockaddr_un *) &xprt->addr;
}

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static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
{
	return (struct sockaddr_in *) &xprt->addr;
}

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static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
{
	return (struct sockaddr_in6 *) &xprt->addr;
}

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static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
{
	struct sockaddr *sap = xs_addr(xprt);
	struct sockaddr_in6 *sin6;
	struct sockaddr_in *sin;
	struct sockaddr_un *sun;
	char buf[128];

	switch (sap->sa_family) {
	case AF_LOCAL:
		sun = xs_addr_un(xprt);
		strlcpy(buf, sun->sun_path, sizeof(buf));
		xprt->address_strings[RPC_DISPLAY_ADDR] =
						kstrdup(buf, GFP_KERNEL);
		break;
	case AF_INET:
		(void)rpc_ntop(sap, buf, sizeof(buf));
		xprt->address_strings[RPC_DISPLAY_ADDR] =
						kstrdup(buf, GFP_KERNEL);
		sin = xs_addr_in(xprt);
		snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
		break;
	case AF_INET6:
		(void)rpc_ntop(sap, buf, sizeof(buf));
		xprt->address_strings[RPC_DISPLAY_ADDR] =
						kstrdup(buf, GFP_KERNEL);
		sin6 = xs_addr_in6(xprt);
		snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
		break;
	default:
		BUG();
	}

	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
}

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static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
{
	struct sockaddr *sap = xs_addr(xprt);
	char buf[128];

	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);

	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
}

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static void xs_format_peer_addresses(struct rpc_xprt *xprt,
				     const char *protocol,
				     const char *netid)
{
	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
	xs_format_common_peer_addresses(xprt);
	xs_format_common_peer_ports(xprt);
}

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static void xs_update_peer_port(struct rpc_xprt *xprt)
{
	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);

	xs_format_common_peer_ports(xprt);
}

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static void xs_free_peer_addresses(struct rpc_xprt *xprt)
{
	unsigned int i;

	for (i = 0; i < RPC_DISPLAY_MAX; i++)
		switch (i) {
		case RPC_DISPLAY_PROTO:
		case RPC_DISPLAY_NETID:
			continue;
		default:
			kfree(xprt->address_strings[i]);
		}
}

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#define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)



static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen, struct kvec *vec, unsigned int base, int more)
{
	struct msghdr msg = {
		.msg_name	= addr,
		.msg_namelen	= addrlen,
		.msg_flags	= XS_SENDMSG_FLAGS | (more ? MSG_MORE : 0),
        };
	struct kvec iov = {
		.iov_base	= vec->iov_base + base,
		.iov_len	= vec->iov_len - base,
        };

	if (iov.iov_len != 0)
		return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
	return kernel_sendmsg(sock, &msg, NULL, 0, 0);
}

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static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more, bool zerocopy, int *sent_p)
{
	ssize_t (*do_sendpage)(struct socket *sock, struct page *page,
			int offset, size_t size, int flags);
	struct page **ppage;
	unsigned int remainder;
	int err;

	remainder = xdr->page_len - base;
	base += xdr->page_base;
	ppage = xdr->pages + (base >> PAGE_SHIFT);
	base &= ~PAGE_MASK;
	do_sendpage = sock->ops->sendpage;
	if (!zerocopy)
		do_sendpage = sock_no_sendpage;
	for(;;) {
		unsigned int len = min_t(unsigned int, PAGE_SIZE - base, remainder);
		int flags = XS_SENDMSG_FLAGS;

		remainder -= len;
		if (more)
			flags |= MSG_MORE;
		if (remainder != 0)
			flags |= MSG_SENDPAGE_NOTLAST | MSG_MORE;
		err = do_sendpage(sock, *ppage, base, len, flags);
		if (remainder == 0 || err != len)
			break;
		*sent_p += err;
		ppage++;
		base = 0;
	}
	if (err > 0) {
		*sent_p += err;
		err = 0;
	}
	return err;
}

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/**
 * xs_sendpages - write pages directly to a socket
 * @sock: socket to send on
 * @addr: UDP only -- address of destination
 * @addrlen: UDP only -- length of destination address
 * @xdr: buffer containing this request
 * @base: starting position in the buffer
 * @zerocopy: true if it is safe to use sendpage()
 * @sent_p: return the total number of bytes successfully queued for sending
 *
 */


static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base, bool zerocopy, int *sent_p)
{
	unsigned int remainder = xdr->len - base;
	int err = 0;
	int sent = 0;

	if (unlikely(!sock))
		return -ENOTSOCK;

	if (base != 0) {
		addr = NULL;
		addrlen = 0;
	}

	if (base < xdr->head[0].iov_len || addr != NULL) {
		unsigned int len = xdr->head[0].iov_len - base;
		remainder -= len;
		err = xs_send_kvec(sock, addr, addrlen, &xdr->head[0], base, remainder != 0);
		if (remainder == 0 || err != len)
			goto out;
		*sent_p += err;
		base = 0;
	} else
		base -= xdr->head[0].iov_len;

	if (base < xdr->page_len) {
		unsigned int len = xdr->page_len - base;
		remainder -= len;
		err = xs_send_pagedata(sock, xdr, base, remainder != 0, zerocopy, &sent);
		*sent_p += sent;
		if (remainder == 0 || sent != len)
			goto out;
		base = 0;
	} else
		base -= xdr->page_len;

	if (base >= xdr->tail[0].iov_len)
		return 0;
	err = xs_send_kvec(sock, NULL, 0, &xdr->tail[0], base, 0);
out:
	if (err > 0) {
		*sent_p += err;
		err = 0;
	}
	return err;
}

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static void xs_nospace_callback(struct rpc_task *task)
{
	struct sock_xprt *transport = container_of(task->tk_rqstp->rq_xprt, struct sock_xprt, xprt);

	transport->inet->sk_write_pending--;
}

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/**
 * xs_nospace - place task on wait queue if transmit was incomplete
 * @task: task to put to sleep
 *
 */


static int xs_nospace(struct rpc_task *task)
{
	struct rpc_rqst *req = task->tk_rqstp;
	struct rpc_xprt *xprt = req->rq_xprt;
	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
	struct sock *sk = transport->inet;
	int ret = -EAGAIN;

	dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
			task->tk_pid, req->rq_slen - req->rq_bytes_sent,
			req->rq_slen);

	/* Protect against races with write_space */
	spin_lock_bh(&xprt->transport_lock);

	/* Don't race with disconnect */
	if (xprt_connected(xprt)) {
		/* wait for more buffer space */
		sk->sk_write_pending++;
		xprt_wait_for_buffer_space(task, xs_nospace_callback);
	} else
		ret = -ENOTCONN;

	spin_unlock_bh(&xprt->transport_lock);

	/* Race breaker in case memory is freed before above code is called */
	if (ret == -EAGAIN) {
		struct socket_wq *wq;

		rcu_read_lock();
		wq = rcu_dereference(sk->sk_wq);
		set_bit(SOCKWQ_ASYNC_NOSPACE, &wq->flags);
		rcu_read_unlock();

		sk->sk_write_space(sk);
	}
	return ret;
}

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/*
 * Construct a stream transport record marker in @buf.
 */


static inline void xs_encode_stream_record_marker(struct xdr_buf *buf)
{
	u32 reclen = buf->len - sizeof(rpc_fraghdr);
	rpc_fraghdr *base = buf->head[0].iov_base;
	*base = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT | reclen);
}

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/**
 * xs_local_send_request - write an RPC request to an AF_LOCAL socket
 * @task: RPC task that manages the state of an RPC request
 *
 * Return values:
 *        0:    The request has been sent
 *   EAGAIN:    The socket was blocked, please call again later to
 *              complete the request
 * ENOTCONN:    Caller needs to invoke connect logic then call again
 *    other:    Some other error occured, the request was not sent
 */


static int xs_local_send_request(struct rpc_task *task)
{
	struct rpc_rqst *req = task->tk_rqstp;
	struct rpc_xprt *xprt = req->rq_xprt;
	struct sock_xprt *transport =
				container_of(xprt, struct sock_xprt, xprt);
	struct xdr_buf *xdr = &req->rq_snd_buf;
	int status;
	int sent = 0;

	xs_encode_stream_record_marker(&req->rq_snd_buf);

	xs_pktdump("packet data:",
			req->rq_svec->iov_base, req->rq_svec->iov_len);

	status = xs_sendpages(transport->sock, NULL, 0, xdr, req->rq_bytes_sent,
			      true, &sent);
	dprintk("RPC:       %s(%u) = %d\n",
			__func__, xdr->len - req->rq_bytes_sent, status);

	if (status == -EAGAIN && sock_writeable(transport->inet))
		status = -ENOBUFS;

	if (likely(sent > 0) || status == 0) {
		req->rq_bytes_sent += sent;
		req->rq_xmit_bytes_sent += sent;
		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
			req->rq_bytes_sent = 0;
			return 0;
		}
		status = -EAGAIN;
	}

	switch (status) {
	case -ENOBUFS:
		break;
	case -EAGAIN:
		status = xs_nospace(task);
		break;
	default:
		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
			-status);
	case -EPIPE:
		xs_close(xprt);
		status = -ENOTCONN;
	}

	return status;
}

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100.00%

/**
 * xs_udp_send_request - write an RPC request to a UDP socket
 * @task: address of RPC task that manages the state of an RPC request
 *
 * Return values:
 *        0:    The request has been sent
 *   EAGAIN:    The socket was blocked, please call again later to
 *              complete the request
 * ENOTCONN:    Caller needs to invoke connect logic then call again
 *    other:    Some other error occurred, the request was not sent
 */


static int xs_udp_send_request(struct rpc_task *task)
{
	struct rpc_rqst *req = task->tk_rqstp;
	struct rpc_xprt *xprt = req->rq_xprt;
	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
	struct xdr_buf *xdr = &req->rq_snd_buf;
	int sent = 0;
	int status;

	xs_pktdump("packet data:",
				req->rq_svec->iov_base,
				req->rq_svec->iov_len);

	if (!xprt_bound(xprt))
		return -ENOTCONN;
	status = xs_sendpages(transport->sock, xs_addr(xprt), xprt->addrlen,
			      xdr, req->rq_bytes_sent, true, &sent);

	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
			xdr->len - req->rq_bytes_sent, status);

	/* firewall is blocking us, don't return -EAGAIN or we end up looping */
	if (status == -EPERM)
		goto process_status;

	if (status == -EAGAIN && sock_writeable(transport->inet))
		status = -ENOBUFS;

	if (sent > 0 || status == 0) {
		req->rq_xmit_bytes_sent += sent;
		if (sent >= req->rq_slen)
			return 0;
		/* Still some bytes left; set up for a retry later. */
		status = -EAGAIN;
	}

process_status:
	switch (status) {
	case -ENOTSOCK:
		status = -ENOTCONN;
		/* Should we call xs_close() here? */
		break;
	case -EAGAIN:
		status = xs_nospace(task);
		break;
	case -ENETUNREACH:
	case -ENOBUFS:
	case -EPIPE:
	case -ECONNREFUSED:
	case -EPERM:
		/* When the server has died, an ICMP port unreachable message
                 * prompts ECONNREFUSED. */
		break;
	default:
		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
			-status);
	}

	return status;
}

Contributors
Person
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Commits
CommitProp
Chuck Lever
179
67.55%
1
12.50%
Trond Myklebust
35
13.21%
4
50.00%
Jason Baron
32
12.08%
2
25.00%
Neil Brown
19
7.17%
1
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Total
265
100.00%
8
100.00%

/**
 * xs_tcp_send_request - write an RPC request to a TCP socket
 * @task: address of RPC task that manages the state of an RPC request
 *
 * Return values:
 *        0:    The request has been sent
 *   EAGAIN:    The socket was blocked, please call again later to
 *              complete the request
 * ENOTCONN:    Caller needs to invoke connect logic then call again
 *    other:    Some other error occurred, the request was not sent
 *
 * XXX: In the case of soft timeouts, should we eventually give up
 *      if sendmsg is not able to make progress?
 */


static int xs_tcp_send_request(struct rpc_task *task)
{
	struct rpc_rqst *req = task->tk_rqstp;
	struct rpc_xprt *xprt = req->rq_xprt;
	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
	struct xdr_buf *xdr = &req->rq_snd_buf;
	bool zerocopy = true;
	bool vm_wait = false;
	int status;
	int sent;

	xs_encode_stream_record_marker(&req->rq_snd_buf);

	xs_pktdump("packet data:",
				req->rq_svec->iov_base,
				req->rq_svec->iov_len);
	/* Don't use zero copy if this is a resend. If the RPC call
         * completes while the socket holds a reference to the pages,
         * then we may end up resending corrupted data.
         */
	if (task->tk_flags & RPC_TASK_SENT)
		zerocopy = false;

	if (test_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state))
		xs_tcp_set_socket_timeouts(xprt, transport->sock);

	/* Continue transmitting the packet/record. We must be careful
         * to cope with writespace callbacks arriving _after_ we have
         * called sendmsg(). */
	while (1) {
		sent = 0;
		status = xs_sendpages(transport->sock, NULL, 0, xdr,
				      req->rq_bytes_sent, zerocopy, &sent);

		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
				xdr->len - req->rq_bytes_sent, status);

		/* If we've sent the entire packet, immediately
                 * reset the count of bytes sent. */
		req->rq_bytes_sent += sent;
		req->rq_xmit_bytes_sent += sent;
		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
			req->rq_bytes_sent = 0;
			return 0;
		}

		WARN_ON_ONCE(sent == 0 && status == 0);

		if (status == -EAGAIN ) {
			/*
                         * Return EAGAIN if we're sure we're hitting the
                         * socket send buffer limits.
                         */
			if (test_bit(SOCK_NOSPACE, &transport->sock->flags))
				break;
			/*
                         * Did we hit a memory allocation failure?
                         */
			if (sent == 0) {
				status = -