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>
 */

#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>

#ifdef RPC_DEBUG
# undef  RPC_DEBUG_DATA
# define RPCDBG_FACILITY	RPCDBG_XPRT
#endif

#define XPRT_MAX_RESVPORT	(800)

#ifdef RPC_DEBUG_DATA
/*
 * Print the buffer contents (first 128 bytes only--just enough for
 * diropres return).
 */
static void
xprt_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
xprt_pktdump(char *msg, u32 *packet, unsigned int count)
{
	/* NOP */
}
#endif

/*
 * Look up RPC transport given an INET socket
 */
static inline struct rpc_xprt *
xprt_from_sock(struct sock *sk)
{
	return (struct rpc_xprt *) sk->sk_user_data;
}

static int
xdr_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen,
		struct xdr_buf *xdr, unsigned int base, int msgflags)
{
	struct page **ppage = xdr->pages;
	unsigned int len, pglen = xdr->page_len;
	int err, ret = 0;
	ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int);

	len = xdr->head[0].iov_len;
	if (base < len || (addr != NULL && base == 0)) {
		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   = msgflags,
		};
		if (xdr->len > len)
			msg.msg_flags |= MSG_MORE;

		if (iov.iov_len != 0)
			err = kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
		else
			err = kernel_sendmsg(sock, &msg, NULL, 0, 0);
		if (ret == 0)
			ret = err;
		else if (err > 0)
			ret += err;
		if (err != iov.iov_len)
			goto out;
		base = 0;
	} else
		base -= len;

	if (pglen == 0)
		goto copy_tail;
	if (base >= pglen) {
		base -= pglen;
		goto copy_tail;
	}
	if (base || xdr->page_base) {
		pglen -= base;
		base  += xdr->page_base;
		ppage += base >> PAGE_CACHE_SHIFT;
		base &= ~PAGE_CACHE_MASK;
	}

	sendpage = sock->ops->sendpage ? : sock_no_sendpage;
	do {
		int flags =