Yiannis Yiakoumis
5731d545f1
netdev uses tc to implement the queueing mechanism. Queue configuration takes place through dpctl. Each queue is represented by a send-only socket, while there is a default socket that receives traffic and sends best-effort traffic. This is necessary to overcome limitations from user-only implementation.
317 lines
10 KiB
C
317 lines
10 KiB
C
/* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
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* Junior University
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*
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* We are making the OpenFlow specification and associated documentation
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* (Software) available for public use and benefit with the expectation
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* that others will use, modify and enhance the Software and contribute
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* those enhancements back to the community. However, since we would
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* like to make the Software available for broadest use, with as few
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* restrictions as possible permission is hereby granted, free of
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* charge, to any person obtaining a copy of this Software to deal in
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* the Software under the copyrights without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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* The name and trademarks of copyright holder(s) may NOT be used in
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* advertising or publicity pertaining to the Software or any
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* derivatives without specific, written prior permission.
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*/
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#include <config.h>
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#include "socket-util.h"
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#include <arpa/inet.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <netdb.h>
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#include <poll.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/resource.h>
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#include <sys/un.h>
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#include <unistd.h>
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#include "fatal-signal.h"
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#include "util.h"
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#include "vlog.h"
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#define THIS_MODULE VLM_socket_util
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/* Sets 'fd' to non-blocking mode. Returns 0 if successful, otherwise a
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* positive errno value. */
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int
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set_nonblocking(int fd)
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{
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int flags = fcntl(fd, F_GETFL, 0);
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if (flags != -1) {
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if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) != -1) {
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return 0;
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} else {
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VLOG_ERR("fcntl(F_SETFL) failed: %s", strerror(errno));
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return errno;
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}
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} else {
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VLOG_ERR("fcntl(F_GETFL) failed: %s", strerror(errno));
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return errno;
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}
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}
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/** Sets the priority for the socket. Returns 0 if successful,
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* otherwise a positive errno value */
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int
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set_socket_priority(int fd, int priority)
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{
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int prio = priority;
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return setsockopt(fd, SOL_SOCKET, SO_PRIORITY, (char *)&prio, sizeof(prio));
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}
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/* Returns the maximum valid FD value, plus 1. */
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int
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get_max_fds(void)
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{
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static int max_fds = -1;
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if (max_fds < 0) {
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struct rlimit r;
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if (!getrlimit(RLIMIT_NOFILE, &r)
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&& r.rlim_cur != RLIM_INFINITY
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&& r.rlim_cur != RLIM_SAVED_MAX
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&& r.rlim_cur != RLIM_SAVED_CUR) {
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max_fds = r.rlim_cur;
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} else {
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VLOG_WARN("failed to obtain fd limit, defaulting to 1024");
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max_fds = 1024;
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}
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}
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return max_fds;
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}
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/* Translates 'host_name', which may be a DNS name or an IP address, into a
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* numeric IP address in '*addr'. Returns 0 if successful, otherwise a
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* positive errno value. */
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int
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lookup_ip(const char *host_name, struct in_addr *addr)
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{
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if (!inet_aton(host_name, addr)) {
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struct hostent *he = gethostbyname(host_name);
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if (he == NULL) {
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struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
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VLOG_ERR_RL(&rl, "gethostbyname(%s): %s", host_name,
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(h_errno == HOST_NOT_FOUND ? "host not found"
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: h_errno == TRY_AGAIN ? "try again"
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: h_errno == NO_RECOVERY ? "non-recoverable error"
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: h_errno == NO_ADDRESS ? "no address"
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: "unknown error"));
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return ENOENT;
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}
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addr->s_addr = *(uint32_t *) he->h_addr;
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}
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return 0;
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}
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/* Returns the error condition associated with socket 'fd' and resets the
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* socket's error status. */
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int
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get_socket_error(int fd)
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{
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int error;
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socklen_t len = sizeof(error);
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if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {
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struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10);
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error = errno;
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VLOG_ERR_RL(&rl, "getsockopt(SO_ERROR): %s", strerror(error));
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}
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return error;
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}
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int
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check_connection_completion(int fd)
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{
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struct pollfd pfd;
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int retval;
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pfd.fd = fd;
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pfd.events = POLLOUT;
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do {
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retval = poll(&pfd, 1, 0);
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} while (retval < 0 && errno == EINTR);
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if (retval == 1) {
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return get_socket_error(fd);
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} else if (retval < 0) {
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static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10);
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VLOG_ERR_RL(&rl, "poll: %s", strerror(errno));
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return errno;
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} else {
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return EAGAIN;
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}
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}
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/* Drain all the data currently in the receive queue of a datagram socket (and
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* possibly additional data). There is no way to know how many packets are in
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* the receive queue, but we do know that the total number of bytes queued does
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* not exceed the receive buffer size, so we pull packets until none are left
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* or we've read that many bytes. */
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int
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drain_rcvbuf(int fd)
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{
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socklen_t rcvbuf_len;
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size_t rcvbuf;
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rcvbuf_len = sizeof rcvbuf;
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if (getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, &rcvbuf_len) < 0) {
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static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10);
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VLOG_ERR_RL(&rl, "getsockopt(SO_RCVBUF) failed: %s", strerror(errno));
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return errno;
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}
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while (rcvbuf > 0) {
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/* In Linux, specifying MSG_TRUNC in the flags argument causes the
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* datagram length to be returned, even if that is longer than the
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* buffer provided. Thus, we can use a 1-byte buffer to discard the
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* incoming datagram and still be able to account how many bytes were
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* removed from the receive buffer.
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*
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* On other Unix-like OSes, MSG_TRUNC has no effect in the flags
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* argument. */
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#ifdef __linux__
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#define BUFFER_SIZE 1
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#else
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#define BUFFER_SIZE 2048
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#endif
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char buffer[BUFFER_SIZE];
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ssize_t n_bytes = recv(fd, buffer, sizeof buffer,
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MSG_TRUNC | MSG_DONTWAIT);
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if (n_bytes <= 0 || n_bytes >= rcvbuf) {
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break;
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}
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rcvbuf -= n_bytes;
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}
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return 0;
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}
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/* Reads and discards up to 'n' datagrams from 'fd', stopping as soon as no
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* more data can be immediately read. ('fd' should therefore be in
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* non-blocking mode.)*/
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void
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drain_fd(int fd, size_t n_packets)
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{
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for (; n_packets > 0; n_packets--) {
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/* 'buffer' only needs to be 1 byte long in most circumstances. This
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* size is defensive against the possibility that we someday want to
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* use a Linux tap device without TUN_NO_PI, in which case a buffer
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* smaller than sizeof(struct tun_pi) will give EINVAL on read. */
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char buffer[128];
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if (read(fd, buffer, sizeof buffer) <= 0) {
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break;
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}
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}
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}
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/* Stores in '*un' a sockaddr_un that refers to file 'name'. Stores in
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* '*un_len' the size of the sockaddr_un. */
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static void
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make_sockaddr_un(const char *name, struct sockaddr_un* un, socklen_t *un_len)
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{
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un->sun_family = AF_UNIX;
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strncpy(un->sun_path, name, sizeof un->sun_path);
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un->sun_path[sizeof un->sun_path - 1] = '\0';
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*un_len = (offsetof(struct sockaddr_un, sun_path)
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+ strlen (un->sun_path) + 1);
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}
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/* Creates a Unix domain socket in the given 'style' (either SOCK_DGRAM or
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* SOCK_STREAM) that is bound to '*bind_path' (if 'bind_path' is non-null) and
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* connected to '*connect_path' (if 'connect_path' is non-null). If 'nonblock'
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* is true, the socket is made non-blocking. If 'passcred' is true, the socket
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* is configured to receive SCM_CREDENTIALS control messages.
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*
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* Returns the socket's fd if successful, otherwise a negative errno value. */
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int
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make_unix_socket(int style, bool nonblock, bool passcred UNUSED,
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const char *bind_path, const char *connect_path)
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{
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int error;
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int fd;
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fd = socket(PF_UNIX, style, 0);
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if (fd < 0) {
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return -errno;
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}
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/* Set nonblocking mode right away, if we want it. This prevents blocking
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* in connect(), if connect_path != NULL. (In turn, that's a corner case:
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* it will only happen if style is SOCK_STREAM or SOCK_SEQPACKET, and only
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* if a backlog of un-accepted connections has built up in the kernel.) */
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if (nonblock) {
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int flags = fcntl(fd, F_GETFL, 0);
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if (flags == -1) {
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goto error;
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}
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if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) {
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goto error;
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}
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}
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if (bind_path) {
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struct sockaddr_un un;
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socklen_t un_len;
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make_sockaddr_un(bind_path, &un, &un_len);
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if (unlink(un.sun_path) && errno != ENOENT) {
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VLOG_WARN("unlinking \"%s\": %s\n", un.sun_path, strerror(errno));
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}
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fatal_signal_add_file_to_unlink(bind_path);
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if (bind(fd, (struct sockaddr*) &un, un_len)
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|| fchmod(fd, S_IRWXU)) {
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goto error;
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}
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}
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if (connect_path) {
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struct sockaddr_un un;
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socklen_t un_len;
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make_sockaddr_un(connect_path, &un, &un_len);
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if (connect(fd, (struct sockaddr*) &un, un_len)
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&& errno != EINPROGRESS) {
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goto error;
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}
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}
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#ifdef SCM_CREDENTIALS
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if (passcred) {
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int enable = 1;
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if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable))) {
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goto error;
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}
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}
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#endif
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return fd;
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error:
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if (bind_path) {
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fatal_signal_remove_file_to_unlink(bind_path);
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}
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error = errno;
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close(fd);
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return -error;
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}
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int
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get_unix_name_len(socklen_t sun_len)
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{
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return (sun_len >= offsetof(struct sockaddr_un, sun_path)
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? sun_len - offsetof(struct sockaddr_un, sun_path)
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: 0);
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}
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