path: root/net/sunrpc/xprtsock.c

/*
 * linux/net/sunrpc/xprtsock.c
 *
 * Client-side transport implementation for sockets.
 *
 * TCP callback races fixes (C) 1998 Red Hat Software <alan@redhat.com>
 * TCP send fixes (C) 1998 Red Hat Software <alan@redhat.com>
 * 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>
 */

#include <linux/types.h>
#include <linux/slab.h>
#include <linux/capability.h>
#include <linux/sched.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/udp.h>
#include <linux/tcp.h>
#include <linux/sunrpc/clnt.h>
#include <linux/file.h>

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

/*
 * Maximum port number to use when requesting a reserved port.
 */
#define XS_MAX_RESVPORT		(800U)

/*
 * How many times to try sending a request on a socket before waiting
 * for the socket buffer to clear.
 */
#define XS_SENDMSG_RETRY	(10U)

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

#define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)

static inline int xs_send_head(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base, unsigned int len)
{
	struct kvec iov = {
		.iov_base	= xdr->head[0].iov_base + base,
		.iov_len	= len - base,
	};
	struct msghdr msg = {
		.msg_name	= addr,
		.msg_namelen	= addrlen,
		.msg_flags	= XS_SENDMSG_FLAGS,
	};

	if (xdr->len > len)
		msg.msg_flags |= MSG_MORE;

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

static int xs_send_tail(struct socket *sock, struct xdr_buf *xdr, unsigned int base, unsigned int len)
{
	struct kvec iov = {
		.iov_base	= xdr->tail[0].iov_base + base,
		.iov_len	= len - base,
	};
	struct msghdr msg = {
		.msg_flags	= XS_SENDMSG_FLAGS,
	};

	return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
}

/**
 * xs_sendpages - write pages directly to a socket
 * @sock: socket to send on
 * @addr: UDP only -- address of destination
 * @addrlen: UDP only