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735683ac615ca00ec62aff107ab1a07df037f543
openflow/lib/netdev.c
T
Ben Pfaff 735683ac61 Move netdev from switch to lib. 
This is in preparation for the secure channel wanting to access
network devices.
2008-05-28 10:46:54 -07:00

593 lines
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/* Copyright (c) 2008 The Board of Trustees of The Leland Stanford
* Junior University
*
* We are making the OpenFlow specification and associated documentation
* (Software) available for public use and benefit with the expectation
* that others will use, modify and enhance the Software and contribute
* those enhancements back to the community. However, since we would
* like to make the Software available for broadest use, with as few
* restrictions as possible permission is hereby granted, free of
* charge, to any person obtaining a copy of this Software to deal in
* the Software under the copyrights without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* The name and trademarks of copyright holder(s) may NOT be used in
* advertising or publicity pertaining to the Software or any
* derivatives without specific, written prior permission.
*/
#include "netdev.h"
#include <assert.h>
#include <errno.h>
#include <arpa/inet.h>
#include <inttypes.h>
#include <linux/types.h>
#include <linux/ethtool.h>
#include <linux/sockios.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netpacket/packet.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <net/if_packet.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "list.h"
#include "fatal-signal.h"
#include "buffer.h"
#include "openflow.h"
#include "packets.h"
#include "poll-loop.h"
#define THIS_MODULE VLM_netdev
#include "vlog.h"
struct netdev {
struct list node;
char *name;
int fd;
uint8_t etheraddr[ETH_ADDR_LEN];
int speed;
int mtu;
uint32_t features;
int save_flags;
};
static struct list netdev_list = LIST_INITIALIZER(&netdev_list);
static void init_netdev(void);
static int restore_flags(struct netdev *netdev);
/* Check whether device NAME has an IPv4 address assigned to it and, if so, log
* an error. */
static void
check_ipv4_address(const char *name)
{
int sock;
struct ifreq ifr;
sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock < 0) {
VLOG_WARN("socket(AF_INET): %s", strerror(errno));
return;
}
strncpy(ifr.ifr_name, name, sizeof ifr.ifr_name);
ifr.ifr_addr.sa_family = AF_INET;
if (ioctl(sock, SIOCGIFADDR, &ifr) == 0) {
VLOG_ERR("%s device has assigned IP address %s", name,
inet_ntoa(((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr));
}
close(sock);
}
/* Check whether device NAME has an IPv6 address assigned to it and, if so, log
* an error. */
static void
check_ipv6_address(const char *name)
{
FILE *file;
char line[128];
file = fopen("/proc/net/if_inet6", "r");
if (file == NULL) {
return;
}
while (fgets(line, sizeof line, file)) {
struct in6_addr in6;
uint8_t *s6 = in6.s6_addr;
char ifname[16 + 1];
#define X8 "%2"SCNx8
if (sscanf(line, " "X8 X8 X8 X8 X8 X8 X8 X8 X8 X8 X8 X8 X8 X8 X8 X8
"%*x %*x %*x %*x %16s\n",
&s6[0], &s6[1], &s6[2], &s6[3],
&s6[4], &s6[5], &s6[6], &s6[7],
&s6[8], &s6[9], &s6[10], &s6[11],
&s6[12], &s6[13], &s6[14], &s6[15],
ifname) == 17
&& !strcmp(name, ifname))
{
char in6_name[INET6_ADDRSTRLEN + 1];
inet_ntop(AF_INET6, &in6, in6_name, sizeof in6_name);
VLOG_ERR("%s device has assigned IPv6 address %s",
name, in6_name);
}
}
fclose(file);
}
static void
do_ethtool(struct netdev *netdev)
{
struct ifreq ifr;
struct ethtool_cmd ecmd;
netdev->speed = 0;
netdev->features = 0;
memset(&ifr, 0, sizeof ifr);
strncpy(ifr.ifr_name, netdev->name, sizeof ifr.ifr_name);
ifr.ifr_data = (caddr_t) &ecmd;
memset(&ecmd, 0, sizeof ecmd);
ecmd.cmd = ETHTOOL_GSET;
if (ioctl(netdev->fd, SIOCETHTOOL, &ifr) == 0) {
if (ecmd.supported & SUPPORTED_10baseT_Half) {
netdev->features |= OFPPF_10MB_HD;
}
if (ecmd.supported & SUPPORTED_10baseT_Full) {
netdev->features |= OFPPF_10MB_FD;
}
if (ecmd.supported & SUPPORTED_100baseT_Half) {
netdev->features |= OFPPF_100MB_HD;
}
if (ecmd.supported & SUPPORTED_100baseT_Full) {
netdev->features |= OFPPF_100MB_FD;
}
if (ecmd.supported & SUPPORTED_1000baseT_Half) {
netdev->features |= OFPPF_1GB_HD;
}
if (ecmd.supported & SUPPORTED_1000baseT_Full) {
netdev->features |= OFPPF_1GB_FD;
}
/* 10Gbps half-duplex doesn't exist... */
if (ecmd.supported & SUPPORTED_10000baseT_Full) {
netdev->features |= OFPPF_10GB_FD;
}
switch (ecmd.speed) {
case SPEED_10:
netdev->speed = 10;
break;
case SPEED_100:
netdev->speed = 100;
break;
case SPEED_1000:
netdev->speed = 1000;
break;
case SPEED_2500:
netdev->speed = 2500;
break;
case SPEED_10000:
netdev->speed = 10000;
break;
}
} else {
VLOG_DBG("ioctl(SIOCETHTOOL) failed: %s", strerror(errno));
}
}
/* Opens the network device named 'name' (e.g. "eth0") and returns zero if
* successful, otherwise a positive errno value. On success, sets '*netdev'
* to the new network device, otherwise to null. */
int
netdev_open(const char *name, struct netdev **netdev_)
{
int fd;
struct sockaddr sa;
struct ifreq ifr;
unsigned int ifindex;
socklen_t rcvbuf_len;
size_t rcvbuf;
uint8_t etheraddr[ETH_ADDR_LEN];
int mtu;
int error;
struct netdev *netdev;
*netdev_ = NULL;
init_netdev();
/* Create raw socket.
*
* We have to use SOCK_PACKET, despite its deprecation, because only
* SOCK_PACKET lets us set the hardware source address of outgoing
* packets. */
fd = socket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ALL));
if (fd < 0) {
return errno;
}
/* Bind to specific ethernet device. */
memset(&sa, 0, sizeof sa);
sa.sa_family = AF_UNSPEC;
strncpy((char *) sa.sa_data, name, sizeof sa.sa_data);
if (bind(fd, &sa, sizeof sa) < 0) {
VLOG_ERR("bind to %s failed: %s", name, strerror(errno));
goto error;
}
/* Between the socket() and bind() calls above, the socket receives all
* packets on all system interfaces. We do not want to receive that
* data, but there is no way to avoid it. So we must now drain out the
* receive queue. There is no way to know how long the receive queue is,
* but we know that the total number of bytes queued does not exceed the
* receive buffer size, so we pull packets until none are left or we've
* read that many bytes. */
rcvbuf_len = sizeof rcvbuf;
if (getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, &rcvbuf_len) < 0) {
VLOG_ERR("getsockopt(SO_RCVBUF) on %s device failed: %s",
name, strerror(errno));
goto error;
}
while (rcvbuf > 0) {
char buffer;
ssize_t n_bytes = recv(fd, &buffer, 1, MSG_TRUNC | MSG_DONTWAIT);
if (n_bytes <= 0) {
break;
}
rcvbuf -= n_bytes;
}
/* Get ethernet device index. */
strncpy(ifr.ifr_name, name, sizeof ifr.ifr_name);
if (ioctl(fd, SIOCGIFINDEX, &ifr) < 0) {
VLOG_ERR("ioctl(SIOCGIFINDEX) on %s device failed: %s",
name, strerror(errno));
goto error;
}
ifindex = ifr.ifr_ifindex;
/* Get MAC address. */
if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
VLOG_ERR("ioctl(SIOCGIFHWADDR) on %s device failed: %s",
name, strerror(errno));
goto error;
}
if (ifr.ifr_hwaddr.sa_family != AF_UNSPEC
&& ifr.ifr_hwaddr.sa_family != ARPHRD_ETHER) {
VLOG_WARN("%s device has unknown hardware address family %d",
name, (int) ifr.ifr_hwaddr.sa_family);
}
memcpy(etheraddr, ifr.ifr_hwaddr.sa_data, sizeof etheraddr);
/* Get MTU. */
if (ioctl(fd, SIOCGIFMTU, &ifr) < 0) {
VLOG_ERR("ioctl(SIOCGIFMTU) on %s device failed: %s",
name, strerror(errno));
goto error;
}
mtu = ifr.ifr_mtu;
/* Allocate network device. */
netdev = xmalloc(sizeof *netdev);
netdev->name = xstrdup(name);
netdev->fd = fd;
memcpy(netdev->etheraddr, etheraddr, sizeof etheraddr);
netdev->mtu = mtu;
/* Get speed, features. */
do_ethtool(netdev);
/* Save flags to restore at close or exit. */
if (ioctl(fd, SIOCGIFFLAGS, &ifr) < 0) {
VLOG_ERR("ioctl(SIOCGIFFLAGS) on %s device failed: %s",
name, strerror(errno));
goto error;
}
netdev->save_flags = ifr.ifr_flags;
fatal_signal_block();
list_push_back(&netdev_list, &netdev->node);
fatal_signal_unblock();
/* Bring up interface and set promiscuous mode. */
ifr.ifr_flags |= IFF_PROMISC | IFF_UP;
if (ioctl(fd, SIOCSIFFLAGS, &ifr) < 0) {
error = errno;
VLOG_ERR("failed to set promiscuous mode on %s device: %s",
name, strerror(errno));
netdev_close(netdev);
return error;
}
/* Complain to administrator if any IP addresses are assigned to the
* interface. We warn about this because packets received for that IP
* address will be processed both by the kernel TCP/IP stack and by us as a
* switch, which produces poor results. */
check_ipv4_address(name);
check_ipv6_address(name);
/* Success! */
*netdev_ = netdev;
return 0;
error:
error = errno;
close(fd);
return error;
}
/* Closes and destroys 'netdev'. */
void
netdev_close(struct netdev *netdev)
{
if (netdev) {
/* Bring down interface and drop promiscuous mode, if we brought up
* the interface or enabled promiscuous mode. */
int error;
fatal_signal_block();
error = restore_flags(netdev);
list_remove(&netdev->node);
fatal_signal_unblock();
if (error) {
VLOG_WARN("failed to restore network device flags on %s: %s",
netdev->name, strerror(error));
}
/* Free. */
free(netdev->name);
close(netdev->fd);
free(netdev);
}
}
/* Pads 'buffer' out with zero-bytes to the minimum valid length of an
* Ethernet packet, if necessary. */
static void
pad_to_minimum_length(struct buffer *buffer)
{
if (buffer->size < ETH_TOTAL_MIN) {
size_t shortage = ETH_TOTAL_MIN - buffer->size;
memset(buffer_put_uninit(buffer, shortage), 0, shortage);
}
}
/* Attempts to receive a packet from 'netdev' into 'buffer', which the caller
* must have initialized with sufficient room for the packet. The space
* required to receive any packet is ETH_HEADER_LEN bytes, plus VLAN_HEADER_LEN
* bytes, plus the device's MTU (which may be retrieved via netdev_get_mtu()).
* (Some devices do not allow for a VLAN header, in which case VLAN_HEADER_LEN
* need not be included.)
*
* If a packet is successfully retrieved, returns 0. In this case 'buffer' is
* guaranteed to contain at least ETH_TOTAL_MIN bytes. Otherwise, returns a
* positive errno value. Returns EAGAIN immediately if no packet is ready to
* be returned.
*/
int
netdev_recv(struct netdev *netdev, struct buffer *buffer)
{
ssize_t n_bytes;
assert(buffer->size == 0);
assert(buffer_tailroom(buffer) >= ETH_TOTAL_MIN);
do {
n_bytes = recv(netdev->fd,
buffer_tail(buffer), buffer_tailroom(buffer),
MSG_DONTWAIT);
} while (n_bytes < 0 && errno == EINTR);
if (n_bytes < 0) {
if (errno != EAGAIN) {
VLOG_WARN("error receiving Ethernet packet on %s: %s",
strerror(errno), netdev->name);
}
return errno;
} else {
buffer->size += n_bytes;
/* When the kernel internally sends out an Ethernet frame on an
* interface, it gives us a copy *before* padding the frame to the
* minimum length. Thus, when it sends out something like an ARP
* request, we see a too-short frame. So pad it out to the minimum
* length. */
pad_to_minimum_length(buffer);
return 0;
}
}
/* Registers with the poll loop to wake up from the next call to poll_block()
* when a packet is ready to be received with netdev_recv() on 'netdev'. */
void
netdev_recv_wait(struct netdev *netdev)
{
poll_fd_wait(netdev->fd, POLLIN);
}
/* Sends 'buffer' on 'netdev'. Returns 0 if successful, otherwise a positive
* errno value. Returns EAGAIN without blocking if the packet cannot be queued
* immediately. Returns EMSGSIZE if a partial packet was transmitted or if
* the packet is too big to transmit on the device.
*
* The kernel maintains a packet transmission queue, so the caller is not
* expected to do additional queuing of packets. */
int
netdev_send(struct netdev *netdev, struct buffer *buffer)
{
ssize_t n_bytes;
const struct eth_header *eh;
struct sockaddr_pkt spkt;
/* Ensure packet is long enough. (Although all incoming packets are at
* least ETH_TOTAL_MIN bytes long, we could have trimmed some data off a
* minimum-size packet, e.g. by dropping a vlan header.)
*
* The kernel does not require this, but it ensures that we always access
* valid memory in grabbing the sockaddr below. */
pad_to_minimum_length(buffer);
/* Construct packet sockaddr, which SOCK_PACKET requires. */
spkt.spkt_family = AF_PACKET;
strncpy((char *) spkt.spkt_device, netdev->name, sizeof spkt.spkt_device);
eh = buffer_at_assert(buffer, 0, sizeof *eh);
spkt.spkt_protocol = eh->eth_type;
do {
n_bytes = sendto(netdev->fd, buffer->data, buffer->size, 0,
(const struct sockaddr *) &spkt, sizeof spkt);
} while (n_bytes < 0 && errno == EINTR);
if (n_bytes < 0) {
/* The Linux AF_PACKET implementation never blocks waiting for room
* for packets, instead returning ENOBUFS. Translate this into EAGAIN
* for the caller. */
if (errno == ENOBUFS) {
return EAGAIN;
} else if (errno != EAGAIN) {
VLOG_WARN("error sending Ethernet packet on %s: %s",
netdev->name, strerror(errno));
}
return errno;
} else if (n_bytes != buffer->size) {
VLOG_WARN("send partial Ethernet packet (%d bytes of %zu) on %s",
(int) n_bytes, buffer->size, netdev->name);
return EMSGSIZE;
} else {
return 0;
}
}
/* Registers with the poll loop to wake up from the next call to poll_block()
* when the packet transmission queue has sufficient room to transmit a packet
* with netdev_send().
*
* The kernel maintains a packet transmission queue, so the client is not
* expected to do additional queuing of packets. Thus, this function is
* unlikely to ever be used. It is included for completeness. */
void
netdev_send_wait(struct netdev *netdev)
{
poll_fd_wait(netdev->fd, POLLOUT);
}
/* Returns a pointer to 'netdev''s MAC address. The caller must not modify or
* free the returned buffer. */
const uint8_t *
netdev_get_etheraddr(const struct netdev *netdev)
{
return netdev->etheraddr;
}
/* Returns the name of the network device that 'netdev' represents,
* e.g. "eth0". The caller must not modify or free the returned string. */
const char *
netdev_get_name(const struct netdev *netdev)
{
return netdev->name;
}
/* Returns the maximum size of transmitted (and received) packets on 'netdev',
* in bytes, not including the hardware header; thus, this is typically 1500
* bytes for Ethernet devices. */
int
netdev_get_mtu(const struct netdev *netdev)
{
return netdev->mtu;
}
/* Returns the current speed of the network device that 'netdev' represents, in
* megabits per second, or 0 if the speed is unknown. */
int
netdev_get_speed(const struct netdev *netdev)
{
return netdev->speed;
}
/* Returns the features supported by 'netdev', as a bitmap of bits from enum
* ofp_phy_port, in host byte order. */
uint32_t
netdev_get_features(const struct netdev *netdev)
{
return netdev->features;
}
static void restore_all_flags(void *aux);
/* Set up a signal hook to restore network device flags on program
* termination. */
static void
init_netdev(void)
{
static bool inited;
if (!inited) {
inited = true;
fatal_signal_add_hook(restore_all_flags, NULL);
}
}
/* Restore the network device flags on 'netdev' to those that were active
* before we changed them. Returns 0 if successful, otherwise a positive
* errno value.
*
* To avoid reentry, the caller must ensure that fatal signals are blocked. */
static int
restore_flags(struct netdev *netdev)
{
struct ifreq ifr;
/* Get current flags. */
strncpy(ifr.ifr_name, netdev->name, sizeof ifr.ifr_name);
if (ioctl(netdev->fd, SIOCGIFFLAGS, &ifr) < 0) {
return errno;
}
/* Restore flags that we might have changed, if necessary. */
if ((ifr.ifr_flags ^ netdev->save_flags) & (IFF_PROMISC | IFF_UP)) {
ifr.ifr_flags &= ~(IFF_PROMISC | IFF_UP);
ifr.ifr_flags |= netdev->save_flags & (IFF_PROMISC | IFF_UP);
if (ioctl(netdev->fd, SIOCSIFFLAGS, &ifr) < 0) {
return errno;
}
}
return 0;
}
/* Retores all the flags on all network devices that we modified. Called from
* a signal handler, so it does not attempt to report error conditions. */
static void
restore_all_flags(void *aux UNUSED)
{
struct netdev *netdev;
LIST_FOR_EACH (netdev, struct netdev, node, &netdev_list) {
restore_flags(netdev);
}
}
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