iPXE
stp.c
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1 /*
2  * Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License as
6  * published by the Free Software Foundation; either version 2 of the
7  * License, or (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17  * 02110-1301, USA.
18  *
19  * You can also choose to distribute this program under the terms of
20  * the Unmodified Binary Distribution Licence (as given in the file
21  * COPYING.UBDL), provided that you have satisfied its requirements.
22  */
23 
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25 
26 #include <errno.h>
27 #include <byteswap.h>
28 #include <ipxe/netdevice.h>
29 #include <ipxe/ethernet.h>
30 #include <ipxe/iobuf.h>
31 #include <ipxe/timer.h>
32 #include <ipxe/stp.h>
33 
34 /** @file
35  *
36  * Spanning Tree Protocol (STP)
37  *
38  */
39 
40 /* Disambiguate the various error causes */
41 #define ENOTSUP_PROTOCOL __einfo_error ( EINFO_ENOTSUP_PROTOCOL )
42 #define EINFO_ENOTSUP_PROTOCOL \
43  __einfo_uniqify ( EINFO_ENOTSUP, 0x02, \
44  "Non-STP packet received" )
45 #define ENOTSUP_VERSION __einfo_error ( EINFO_ENOTSUP_VERSION )
46 #define EINFO_ENOTSUP_VERSION \
47  __einfo_uniqify ( EINFO_ENOTSUP, 0x03, \
48  "Legacy STP packet received" )
49 #define ENOTSUP_TYPE __einfo_error ( EINFO_ENOTSUP_TYPE )
50 #define EINFO_ENOTSUP_TYPE \
51  __einfo_uniqify ( EINFO_ENOTSUP, 0x04, \
52  "Non-RSTP packet received" )
53 
54 /**
55  * Process incoming STP packets
56  *
57  * @v iobuf I/O buffer
58  * @v netdev Network device
59  * @v ll_source Link-layer source address
60  * @v flags Packet flags
61  * @ret rc Return status code
62  */
63 static int stp_rx ( struct io_buffer *iobuf, struct net_device *netdev,
64  const void *ll_dest __unused,
65  const void *ll_source __unused,
66  unsigned int flags __unused ) {
67  struct stp_bpdu *stp;
68  unsigned int hello;
69  int rc;
70 
71  /* Sanity check */
72  if ( iob_len ( iobuf ) < sizeof ( *stp ) ) {
73  DBGC ( netdev, "STP %s received underlength packet (%zd "
74  "bytes):\n", netdev->name, iob_len ( iobuf ) );
75  DBGC_HDA ( netdev, 0, iobuf->data, iob_len ( iobuf ) );
76  rc = -EINVAL;
77  goto done;
78  }
79  stp = iobuf->data;
80 
81  /* Ignore non-RSTP packets */
82  if ( stp->protocol != htons ( STP_PROTOCOL ) ) {
83  DBGC ( netdev, "STP %s ignoring non-STP packet (protocol "
84  "%#04x)\n", netdev->name, ntohs ( stp->protocol ) );
86  goto done;
87  }
88  if ( stp->version < STP_VERSION_RSTP ) {
89  DBGC ( netdev, "STP %s received legacy STP packet (version "
90  "%#02x)\n", netdev->name, stp->version );
92  goto done;
93  }
94  if ( stp->type != STP_TYPE_RSTP ) {
95  DBGC ( netdev, "STP %s received non-RSTP packet (type %#02x)\n",
96  netdev->name, stp->type );
97  rc = -ENOTSUP_TYPE;
98  goto done;
99  }
100 
101  /* Dump information */
102  DBGC2 ( netdev, "STP %s %s port %#04x flags %#02x hello %d delay %d\n",
103  netdev->name, eth_ntoa ( stp->sender.mac ), ntohs ( stp->port ),
104  stp->flags, ntohs ( stp->hello ), ntohs ( stp->delay ) );
105 
106  /* Check if port is forwarding */
107  if ( ! ( stp->flags & STP_FL_FORWARDING ) ) {
108  /* Port is not forwarding: block link for two hello times */
109  DBGC ( netdev, "STP %s %s port %#04x flags %#02x is not "
110  "forwarding\n",
111  netdev->name, eth_ntoa ( stp->sender.mac ),
112  ntohs ( stp->port ), stp->flags );
113  hello = ( ntohs ( stp->hello ) * ( TICKS_PER_SEC / 256 ) );
114  netdev_link_block ( netdev, ( hello * 2 ) );
115  rc = -ENETUNREACH;
116  goto done;
117  }
118 
119  /* Success */
120  if ( netdev_link_blocked ( netdev ) ) {
121  DBGC ( netdev, "STP %s %s port %#04x flags %#02x is "
122  "forwarding\n",
123  netdev->name, eth_ntoa ( stp->sender.mac ),
124  ntohs ( stp->port ), stp->flags );
125  }
127  rc = 0;
128 
129  done:
130  free_iob ( iobuf );
131  return rc;
132 }
133 
134 /**
135  * Transcribe STP address
136  *
137  * @v net_addr STP address
138  * @ret string "<STP>"
139  *
140  * This operation is meaningless for the STP protocol.
141  */
142 static const char * stp_ntoa ( const void *net_addr __unused ) {
143  return "<STP>";
144 }
145 
146 /** STP network protocol */
147 struct net_protocol stp_protocol __net_protocol = {
148  .name = "STP",
149  .net_proto = htons ( ETH_P_STP ),
150  .rx = stp_rx,
151  .ntoa = stp_ntoa,
152 };
#define EINVAL
Invalid argument.
Definition: errno.h:428
struct arbelprm_rc_send_wqe rc
Definition: arbel.h:14
const char * name
Protocol name.
Definition: netdevice.h:66
#define TICKS_PER_SEC
Number of ticks per second.
Definition: timer.h:15
#define ENOTSUP_TYPE
Definition: stp.c:49
uint16_t protocol
Protocol ID.
Definition: stp.h:39
A Spanning Tree bridge protocol data unit.
Definition: stp.h:31
Error codes.
uint8_t version
Protocol version.
Definition: stp.h:41
static const char * stp_ntoa(const void *net_addr __unused)
Transcribe STP address.
Definition: stp.c:142
I/O buffers.
void free_iob(struct io_buffer *iobuf)
Free I/O buffer.
Definition: iobuf.c:145
struct stp_switch sender
Sender switch.
Definition: stp.h:51
#define DBGC(...)
Definition: compiler.h:505
iPXE timers
#define ntohs(value)
Definition: byteswap.h:136
static int netdev_link_blocked(struct net_device *netdev)
Check link block state of network device.
Definition: netdevice.h:641
#define ENOTSUP_VERSION
Definition: stp.c:45
uint8_t flags
Flags.
Definition: stp.h:45
void netdev_link_block(struct net_device *netdev, unsigned long timeout)
Mark network device link as being blocked.
Definition: netdevice.c:203
Ethernet protocol.
#define DBGC_HDA(...)
Definition: compiler.h:506
void netdev_link_unblock(struct net_device *netdev)
Mark network device link as being unblocked.
Definition: netdevice.c:218
#define STP_TYPE_RSTP
Rapid Spanning Tree bridge PDU type.
Definition: stp.h:71
static struct net_device * netdev
Definition: gdbudp.c:52
Spanning Tree Protocol (STP)
uint16_t delay
Forward delay.
Definition: stp.h:61
static size_t iob_len(struct io_buffer *iobuf)
Calculate length of data in an I/O buffer.
Definition: iobuf.h:151
const char * eth_ntoa(const void *ll_addr)
Transcribe Ethernet address.
Definition: ethernet.c:175
A network device.
Definition: netdevice.h:348
uint16_t hello
Hello time.
Definition: stp.h:38
uint8_t type
Message type.
Definition: stp.h:43
uint16_t port
Port.
Definition: stp.h:53
uint8_t mac[ETH_ALEN]
MAC address.
Definition: stp.h:27
#define STP_FL_FORWARDING
Port is forwarding.
Definition: stp.h:74
#define STP_PROTOCOL
Spanning Tree protocol ID.
Definition: stp.h:65
A network-layer protocol.
Definition: netdevice.h:64
static int stp_rx(struct io_buffer *iobuf, struct net_device *netdev, const void *ll_dest __unused, const void *ll_source __unused, unsigned int flags __unused)
Process incoming STP packets.
Definition: stp.c:63
Network device management.
#define ENOTSUP_PROTOCOL
Definition: stp.c:41
#define __unused
Declare a variable or data structure as unused.
Definition: compiler.h:573
char name[NETDEV_NAME_LEN]
Name of this network device.
Definition: netdevice.h:358
#define DBGC2(...)
Definition: compiler.h:522
void * data
Start of data.
Definition: iobuf.h:44
FILE_LICENCE(GPL2_OR_LATER_OR_UBDL)
#define ETH_P_STP
"Protocol" value for STP
Definition: stp.h:20
#define STP_VERSION_RSTP
Rapid Spanning Tree protocol version.
Definition: stp.h:68
uint16_t hello
Hello time.
Definition: stp.h:59
#define ENETUNREACH
Network unreachable.
Definition: errno.h:488
#define htons(value)
Definition: byteswap.h:135
struct bofm_section_header done
Definition: bofm_test.c:46
struct net_protocol stp_protocol __net_protocol
STP network protocol.
Definition: stp.c:147
A persistent I/O buffer.
Definition: iobuf.h:32
uint8_t flags
Flags.
Definition: ena.h:18