1: /*
2: * Public definitions pertaining to the Forwarding Plane Manager component.
3: *
4: * Permission is granted to use, copy, modify and/or distribute this
5: * software under either one of the licenses below.
6: *
7: * Note that if you use other files from the Quagga tree directly or
8: * indirectly, then the licenses in those files still apply.
9: *
10: * Please retain both licenses below when modifying this code in the
11: * Quagga tree.
12: *
13: * Copyright (C) 2012 by Open Source Routing.
14: * Copyright (C) 2012 by Internet Systems Consortium, Inc. ("ISC")
15: */
16:
17: /*
18: * License Option 1: GPL
19: *
20: * This program is free software; you can redistribute it and/or modify it
21: * under the terms of the GNU General Public License as published by the Free
22: * Software Foundation; either version 2 of the License, or (at your option)
23: * any later version.
24: *
25: * This program is distributed in the hope that it will be useful,but WITHOUT
26: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
27: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
28: * more details.
29: *
30: * You should have received a copy of the GNU General Public License along
31: * with this program; if not, write to the Free Software Foundation, Inc.,
32: * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
33: */
34:
35: /*
36: * License Option 2: ISC License
37: *
38: * Permission to use, copy, modify, and/or distribute this software
39: * for any purpose with or without fee is hereby granted, provided
40: * that the above copyright notice and this permission notice appear
41: * in all copies.
42: *
43: * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
44: * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
45: * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
46: * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
47: * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
48: * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
49: * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
50: * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
51: */
52:
53: #ifndef _FPM_H
54: #define _FPM_H
55:
56: /*
57: * The Forwarding Plane Manager (FPM) is an optional component that
58: * may be used in scenarios where the router has a forwarding path
59: * that is distinct from the kernel, commonly a hardware-based fast
60: * path. It is responsible for programming forwarding information
61: * (such as routes and nexthops) in the fast path.
62: *
63: * In Quagga, the Routing Information Base is maintained in the
64: * 'zebra' infrastructure daemon. Routing protocols communicate their
65: * best routes to zebra, and zebra computes the best route across
66: * protocols for each prefix. This latter information comprises the
67: * bulk of the Forwarding Information Base.
68: *
69: * This header file defines a point-to-point interface using which
70: * zebra can update the FPM about changes in routes. The communication
71: * takes place over a stream socket. The FPM listens on a well-known
72: * TCP port, and zebra initiates the connection.
73: *
74: * All messages sent over the connection start with a short FPM
75: * header, fpm_msg_hdr_t. In the case of route add/delete messages,
76: * the header is followed by a netlink message. Zebra should send a
77: * complete copy of the forwarding table(s) to the FPM, including
78: * routes that it may have picked up from the kernel.
79: *
80: * The FPM interface uses replace semantics. That is, if a 'route add'
81: * message for a prefix is followed by another 'route add' message, the
82: * information in the second message is complete by itself, and replaces
83: * the information sent in the first message.
84: *
85: * If the connection to the FPM goes down for some reason, the client
86: * (zebra) should send the FPM a complete copy of the forwarding
87: * table(s) when it reconnects.
88: */
89:
90: #define FPM_DEFAULT_PORT 2620
91:
92: /*
93: * Largest message that can be sent to or received from the FPM.
94: */
95: #define FPM_MAX_MSG_LEN 4096
96:
97: /*
98: * Header that precedes each fpm message to/from the FPM.
99: */
100: typedef struct fpm_msg_hdr_t_
101: {
102: /*
103: * Protocol version.
104: */
105: uint8_t version;
106:
107: /*
108: * Type of message, see below.
109: */
110: uint8_t msg_type;
111:
112: /*
113: * Length of entire message, including the header, in network byte
114: * order.
115: *
116: * Note that msg_len is rounded up to make sure that message is at
117: * the desired alignment. This means that some payloads may need
118: * padding at the end.
119: */
120: uint16_t msg_len;
121: } fpm_msg_hdr_t;
122:
123: /*
124: * The current version of the FPM protocol is 1.
125: */
126: #define FPM_PROTO_VERSION 1
127:
128: typedef enum fpm_msg_type_e_ {
129: FPM_MSG_TYPE_NONE = 0,
130:
131: /*
132: * Indicates that the payload is a completely formed netlink
133: * message.
134: */
135: FPM_MSG_TYPE_NETLINK = 1,
136: } fpm_msg_type_e;
137:
138: /*
139: * The FPM message header is aligned to the same boundary as netlink
140: * messages (4). This means that a netlink message does not need
141: * padding when encapsulated in an FPM message.
142: */
143: #define FPM_MSG_ALIGNTO 4
144:
145: /*
146: * fpm_msg_align
147: *
148: * Round up the given length to the desired alignment.
149: */
150: static inline size_t
151: fpm_msg_align (size_t len)
152: {
153: return (len + FPM_MSG_ALIGNTO - 1) & ~(FPM_MSG_ALIGNTO - 1);
154: }
155:
156: /*
157: * The (rounded up) size of the FPM message header. This ensures that
158: * the message payload always starts at an aligned address.
159: */
160: #define FPM_MSG_HDR_LEN (fpm_msg_align (sizeof (fpm_msg_hdr_t)))
161:
162: /*
163: * fpm_data_len_to_msg_len
164: *
165: * The length value that should be placed in the msg_len field of the
166: * header for a *payload* of size 'data_len'.
167: */
168: static inline size_t
169: fpm_data_len_to_msg_len (size_t data_len)
170: {
171: return fpm_msg_align (data_len) + FPM_MSG_HDR_LEN;
172: }
173:
174: /*
175: * fpm_msg_data
176: *
177: * Pointer to the payload of the given fpm header.
178: */
179: static inline void *
180: fpm_msg_data (fpm_msg_hdr_t *hdr)
181: {
182: return ((char*) hdr) + FPM_MSG_HDR_LEN;
183: }
184:
185: /*
186: * fpm_msg_len
187: */
188: static inline size_t
189: fpm_msg_len (const fpm_msg_hdr_t *hdr)
190: {
191: return ntohs (hdr->msg_len);
192: }
193:
194: /*
195: * fpm_msg_data_len
196: */
197: static inline size_t
198: fpm_msg_data_len (const fpm_msg_hdr_t *hdr)
199: {
200: return (fpm_msg_len (hdr) - FPM_MSG_HDR_LEN);
201: }
202:
203: /*
204: * fpm_msg_next
205: *
206: * Move to the next message in a buffer.
207: */
208: static inline fpm_msg_hdr_t *
209: fpm_msg_next (fpm_msg_hdr_t *hdr, size_t *len)
210: {
211: size_t msg_len;
212:
213: msg_len = fpm_msg_len (hdr);
214:
215: if (len) {
216: if (*len < msg_len)
217: {
218: assert(0);
219: return NULL;
220: }
221: *len -= msg_len;
222: }
223:
224: return (fpm_msg_hdr_t *) (((char*) hdr) + msg_len);
225: }
226:
227: /*
228: * fpm_msg_hdr_ok
229: *
230: * Returns TRUE if a message header looks well-formed.
231: */
232: static inline int
233: fpm_msg_hdr_ok (const fpm_msg_hdr_t *hdr)
234: {
235: size_t msg_len;
236:
237: if (hdr->msg_type == FPM_MSG_TYPE_NONE)
238: return 0;
239:
240: msg_len = fpm_msg_len (hdr);
241:
242: if (msg_len < FPM_MSG_HDR_LEN || msg_len > FPM_MAX_MSG_LEN)
243: return 0;
244:
245: if (fpm_msg_align (msg_len) != msg_len)
246: return 0;
247:
248: return 1;
249: }
250:
251: /*
252: * fpm_msg_ok
253: *
254: * Returns TRUE if a message looks well-formed.
255: *
256: * @param len The length in bytes from 'hdr' to the end of the buffer.
257: */
258: static inline int
259: fpm_msg_ok (const fpm_msg_hdr_t *hdr, size_t len)
260: {
261: if (len < FPM_MSG_HDR_LEN)
262: return 0;
263:
264: if (!fpm_msg_hdr_ok (hdr))
265: return 0;
266:
267: if (fpm_msg_len (hdr) > len)
268: return 0;
269:
270: return 1;
271: }
272:
273: #endif /* _FPM_H */
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