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 */
stp_rx(struct io_buffer * iobuf,struct net_device * netdev,const void * ll_dest __unused,const void * ll_source __unused,unsigned int flags __unused)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 ) );
85 rc = -ENOTSUP_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 );
91 rc = -ENOTSUP_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 }
126 netdev_link_unblock ( netdev );
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 */
stp_ntoa(const void * net_addr __unused)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 };
153