blob: 707ba55f36f96c4fd48407e17dd979c597e41289 [file] [log] [blame]
/*
* RAW transport layer over SOCK_STREAM sockets.
*
* Copyright 2000-2012 Willy Tarreau <w@1wt.eu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <netinet/tcp.h>
#include <common/buffer.h>
#include <common/compat.h>
#include <common/config.h>
#include <common/debug.h>
#include <common/standard.h>
#include <common/ticks.h>
#include <common/time.h>
#include <proto/connection.h>
#include <proto/fd.h>
#include <proto/freq_ctr.h>
#include <proto/log.h>
#include <proto/pipe.h>
#include <proto/raw_sock.h>
#include <proto/stream_interface.h>
#include <proto/task.h>
#include <types/global.h>
#if defined(CONFIG_HAP_LINUX_SPLICE)
#include <common/splice.h>
/* A pipe contains 16 segments max, and it's common to see segments of 1448 bytes
* because of timestamps. Use this as a hint for not looping on splice().
*/
#define SPLICE_FULL_HINT 16*1448
/* how many data we attempt to splice at once when the buffer is configured for
* infinite forwarding */
#define MAX_SPLICE_AT_ONCE (1<<30)
/* Versions of splice between 2.6.25 and 2.6.27.12 were bogus and would return EAGAIN
* on incoming shutdowns. On these versions, we have to call recv() after such a return
* in order to find whether splice is OK or not. Since 2.6.27.13 we don't need to do
* this anymore, and we can avoid this logic by defining ASSUME_SPLICE_WORKS.
*/
/* Returns :
* -1 if splice() is not supported
* >= 0 to report the amount of spliced bytes.
* connection flags are updated (error, read0, wait_room, wait_data).
* The caller must have previously allocated the pipe.
*/
int raw_sock_to_pipe(struct connection *conn, struct pipe *pipe, unsigned int count)
{
#ifndef ASSUME_SPLICE_WORKS
static int splice_detects_close;
#endif
int ret;
int retval = 0;
if (!conn_ctrl_ready(conn))
return 0;
if (!fd_recv_ready(conn->t.sock.fd))
return 0;
errno = 0;
/* Under Linux, if FD_POLL_HUP is set, we have reached the end.
* Since older splice() implementations were buggy and returned
* EAGAIN on end of read, let's bypass the call to splice() now.
*/
if (unlikely(!(fdtab[conn->t.sock.fd].ev & FD_POLL_IN))) {
/* stop here if we reached the end of data */
if ((fdtab[conn->t.sock.fd].ev & (FD_POLL_ERR|FD_POLL_HUP)) == FD_POLL_HUP)
goto out_read0;
/* report error on POLL_ERR before connection establishment */
if ((fdtab[conn->t.sock.fd].ev & FD_POLL_ERR) && (conn->flags & CO_FL_WAIT_L4_CONN)) {
conn->flags |= CO_FL_ERROR | CO_FL_SOCK_RD_SH | CO_FL_SOCK_WR_SH;
errno = 0; /* let the caller do a getsockopt() if it wants it */
return retval;
}
}
while (count) {
if (count > MAX_SPLICE_AT_ONCE)
count = MAX_SPLICE_AT_ONCE;
ret = splice(conn->t.sock.fd, NULL, pipe->prod, NULL, count,
SPLICE_F_MOVE|SPLICE_F_NONBLOCK);
if (ret <= 0) {
if (ret == 0) {
/* connection closed. This is only detected by
* recent kernels (>= 2.6.27.13). If we notice
* it works, we store the info for later use.
*/
#ifndef ASSUME_SPLICE_WORKS
splice_detects_close = 1;
#endif
goto out_read0;
}
if (errno == EAGAIN) {
/* there are two reasons for EAGAIN :
* - nothing in the socket buffer (standard)
* - pipe is full
* - the connection is closed (kernel < 2.6.27.13)
* The last case is annoying but know if we can detect it
* and if we can't then we rely on the call to recv() to
* get a valid verdict. The difference between the first
* two situations is problematic. Since we don't know if
* the pipe is full, we'll stop if the pipe is not empty.
* Anyway, we will almost always fill/empty the pipe.
*/
if (pipe->data) {
/* alway stop reading until the pipe is flushed */
conn->flags |= CO_FL_WAIT_ROOM;
break;
}
/* We don't know if the connection was closed,
* but if we know splice detects close, then we
* know it for sure.
* But if we're called upon POLLIN with an empty
* pipe and get EAGAIN, it is suspect enough to
* try to fall back to the normal recv scheme
* which will be able to deal with the situation.
*/
#ifndef ASSUME_SPLICE_WORKS
if (splice_detects_close)
#endif
fd_cant_recv(conn->t.sock.fd); /* we know for sure that it's EAGAIN */
break;
}
else if (errno == ENOSYS || errno == EINVAL || errno == EBADF) {
/* splice not supported on this end, disable it.
* We can safely return -1 since there is no
* chance that any data has been piped yet.
*/
return -1;
}
else if (errno == EINTR) {
/* try again */
continue;
}
/* here we have another error */
conn->flags |= CO_FL_ERROR;
break;
} /* ret <= 0 */
retval += ret;
pipe->data += ret;
count -= ret;
if (pipe->data >= SPLICE_FULL_HINT || ret >= global.tune.recv_enough) {
/* We've read enough of it for this time, let's stop before
* being asked to poll.
*/
conn->flags |= CO_FL_WAIT_ROOM;
fd_done_recv(conn->t.sock.fd);
break;
}
} /* while */
if (unlikely(conn->flags & CO_FL_WAIT_L4_CONN) && retval)
conn->flags &= ~CO_FL_WAIT_L4_CONN;
return retval;
out_read0:
conn_sock_read0(conn);
conn->flags &= ~CO_FL_WAIT_L4_CONN;
return retval;
}
/* Send as many bytes as possible from the pipe to the connection's socket.
*/
int raw_sock_from_pipe(struct connection *conn, struct pipe *pipe)
{
int ret, done;
if (!conn_ctrl_ready(conn))
return 0;
if (!fd_send_ready(conn->t.sock.fd))
return 0;
done = 0;
while (pipe->data) {
ret = splice(pipe->cons, NULL, conn->t.sock.fd, NULL, pipe->data,
SPLICE_F_MOVE|SPLICE_F_NONBLOCK);
if (ret <= 0) {
if (ret == 0 || errno == EAGAIN) {
fd_cant_send(conn->t.sock.fd);
break;
}
else if (errno == EINTR)
continue;
/* here we have another error */
conn->flags |= CO_FL_ERROR;
break;
}
done += ret;
pipe->data -= ret;
}
if (unlikely(conn->flags & CO_FL_WAIT_L4_CONN) && done)
conn->flags &= ~CO_FL_WAIT_L4_CONN;
return done;
}
#endif /* CONFIG_HAP_LINUX_SPLICE */
/* Receive up to <count> bytes from connection <conn>'s socket and store them
* into buffer <buf>. Only one call to recv() is performed, unless the
* buffer wraps, in which case a second call may be performed. The connection's
* flags are updated with whatever special event is detected (error, read0,
* empty). The caller is responsible for taking care of those events and
* avoiding the call if inappropriate. The function does not call the
* connection's polling update function, so the caller is responsible for this.
* errno is cleared before starting so that the caller knows that if it spots an
* error without errno, it's pending and can be retrieved via getsockopt(SO_ERROR).
*/
static int raw_sock_to_buf(struct connection *conn, struct buffer *buf, int count)
{
int ret, done = 0;
int try;
if (!conn_ctrl_ready(conn))
return 0;
if (!fd_recv_ready(conn->t.sock.fd))
return 0;
errno = 0;
if (unlikely(!(fdtab[conn->t.sock.fd].ev & FD_POLL_IN))) {
/* stop here if we reached the end of data */
if ((fdtab[conn->t.sock.fd].ev & (FD_POLL_ERR|FD_POLL_HUP)) == FD_POLL_HUP)
goto read0;
/* report error on POLL_ERR before connection establishment */
if ((fdtab[conn->t.sock.fd].ev & FD_POLL_ERR) && (conn->flags & CO_FL_WAIT_L4_CONN)) {
conn->flags |= CO_FL_ERROR | CO_FL_SOCK_RD_SH | CO_FL_SOCK_WR_SH;
return done;
}
}
/* let's realign the buffer to optimize I/O */
if (buffer_empty(buf))
buf->p = buf->data;
/* read the largest possible block. For this, we perform only one call
* to recv() unless the buffer wraps and we exactly fill the first hunk,
* in which case we accept to do it once again. A new attempt is made on
* EINTR too.
*/
while (count > 0) {
/* first check if we have some room after p+i */
try = buf->data + buf->size - (buf->p + buf->i);
/* otherwise continue between data and p-o */
if (try <= 0) {
try = buf->p - (buf->data + buf->o);
if (try <= 0)
break;
}
if (try > count)
try = count;
ret = recv(conn->t.sock.fd, bi_end(buf), try, 0);
if (ret > 0) {
buf->i += ret;
done += ret;
if (ret < try) {
/* unfortunately, on level-triggered events, POLL_HUP
* is generally delivered AFTER the system buffer is
* empty, unless the poller supports POLL_RDHUP. If
* we know this is the case, we don't try to read more
* as we know there's no more available. Similarly, if
* there's no problem with lingering we don't even try
* to read an unlikely close from the client since we'll
* close first anyway.
*/
if (fdtab[conn->t.sock.fd].ev & FD_POLL_HUP)
goto read0;
if ((!fdtab[conn->t.sock.fd].linger_risk) ||
(cur_poller.flags & HAP_POLL_F_RDHUP)) {
fd_done_recv(conn->t.sock.fd);
break;
}
}
count -= ret;
}
else if (ret == 0) {
goto read0;
}
else if (errno == EAGAIN || errno == ENOTCONN) {
fd_cant_recv(conn->t.sock.fd);
break;
}
else if (errno != EINTR) {
conn->flags |= CO_FL_ERROR | CO_FL_SOCK_RD_SH | CO_FL_SOCK_WR_SH;
break;
}
}
if (unlikely(conn->flags & CO_FL_WAIT_L4_CONN) && done)
conn->flags &= ~CO_FL_WAIT_L4_CONN;
return done;
read0:
conn_sock_read0(conn);
conn->flags &= ~CO_FL_WAIT_L4_CONN;
/* Now a final check for a possible asynchronous low-level error
* report. This can happen when a connection receives a reset
* after a shutdown, both POLL_HUP and POLL_ERR are queued, and
* we might have come from there by just checking POLL_HUP instead
* of recv()'s return value 0, so we have no way to tell there was
* an error without checking.
*/
if (unlikely(fdtab[conn->t.sock.fd].ev & FD_POLL_ERR))
conn->flags |= CO_FL_ERROR | CO_FL_SOCK_RD_SH | CO_FL_SOCK_WR_SH;
return done;
}
/* Send all pending bytes from buffer <buf> to connection <conn>'s socket.
* <flags> may contain some CO_SFL_* flags to hint the system about other
* pending data for example.
* Only one call to send() is performed, unless the buffer wraps, in which case
* a second call may be performed. The connection's flags are updated with
* whatever special event is detected (error, empty). The caller is responsible
* for taking care of those events and avoiding the call if inappropriate. The
* function does not call the connection's polling update function, so the caller
* is responsible for this.
*/
static int raw_sock_from_buf(struct connection *conn, struct buffer *buf, int flags)
{
int ret, try, done, send_flag;
if (!conn_ctrl_ready(conn))
return 0;
if (!fd_send_ready(conn->t.sock.fd))
return 0;
done = 0;
/* send the largest possible block. For this we perform only one call
* to send() unless the buffer wraps and we exactly fill the first hunk,
* in which case we accept to do it once again.
*/
while (buf->o) {
try = buf->o;
/* outgoing data may wrap at the end */
if (buf->data + try > buf->p)
try = buf->data + try - buf->p;
send_flag = MSG_DONTWAIT | MSG_NOSIGNAL;
if (try < buf->o || flags & CO_SFL_MSG_MORE)
send_flag |= MSG_MORE;
ret = send(conn->t.sock.fd, bo_ptr(buf), try, send_flag);
if (ret > 0) {
buf->o -= ret;
done += ret;
if (likely(buffer_empty(buf)))
/* optimize data alignment in the buffer */
buf->p = buf->data;
/* if the system buffer is full, don't insist */
if (ret < try)
break;
}
else if (ret == 0 || errno == EAGAIN || errno == ENOTCONN) {
/* nothing written, we need to poll for write first */
fd_cant_send(conn->t.sock.fd);
break;
}
else if (errno != EINTR) {
conn->flags |= CO_FL_ERROR | CO_FL_SOCK_RD_SH | CO_FL_SOCK_WR_SH;
break;
}
}
if (unlikely(conn->flags & CO_FL_WAIT_L4_CONN) && done)
conn->flags &= ~CO_FL_WAIT_L4_CONN;
return done;
}
/* transport-layer operations for RAW sockets */
static struct xprt_ops raw_sock = {
.snd_buf = raw_sock_from_buf,
.rcv_buf = raw_sock_to_buf,
#if defined(CONFIG_HAP_LINUX_SPLICE)
.rcv_pipe = raw_sock_to_pipe,
.snd_pipe = raw_sock_from_pipe,
#endif
.shutr = NULL,
.shutw = NULL,
.close = NULL,
.name = "RAW",
};
__attribute__((constructor))
static void __raw_sock_init(void)
{
xprt_register(XPRT_RAW, &raw_sock);
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/