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| -rw-r--r-- | fpm/fpm.h | 273 |
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diff --git a/fpm/fpm.h b/fpm/fpm.h new file mode 100644 index 00000000..96f05f48 --- /dev/null +++ b/fpm/fpm.h @@ -0,0 +1,273 @@ +/* + * Public definitions pertaining to the Forwarding Plane Manager component. + * + * Permission is granted to use, copy, modify and/or distribute this + * software under either one of the licenses below. + * + * Note that if you use other files from the Quagga tree directly or + * indirectly, then the licenses in those files still apply. + * + * Please retain both licenses below when modifying this code in the + * Quagga tree. + * + * Copyright (C) 2012 by Open Source Routing. + * Copyright (C) 2012 by Internet Systems Consortium, Inc. ("ISC") + */ + +/* + * License Option 1: GPL + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful,but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +/* + * License Option 2: ISC License + * + * Permission to use, copy, modify, and/or distribute this software + * for any purpose with or without fee is hereby granted, provided + * that the above copyright notice and this permission notice appear + * in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL + * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE + * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR + * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS + * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, + * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN + * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#ifndef _FPM_H +#define _FPM_H + +/* + * The Forwarding Plane Manager (FPM) is an optional component that + * may be used in scenarios where the router has a forwarding path + * that is distinct from the kernel, commonly a hardware-based fast + * path. It is responsible for programming forwarding information + * (such as routes and nexthops) in the fast path. + * + * In Quagga, the Routing Information Base is maintained in the + * 'zebra' infrastructure daemon. Routing protocols communicate their + * best routes to zebra, and zebra computes the best route across + * protocols for each prefix. This latter information comprises the + * bulk of the Forwarding Information Base. + * + * This header file defines a point-to-point interface using which + * zebra can update the FPM about changes in routes. The communication + * takes place over a stream socket. The FPM listens on a well-known + * TCP port, and zebra initiates the connection. + * + * All messages sent over the connection start with a short FPM + * header, fpm_msg_hdr_t. In the case of route add/delete messages, + * the header is followed by a netlink message. Zebra should send a + * complete copy of the forwarding table(s) to the FPM, including + * routes that it may have picked up from the kernel. + * + * The FPM interface uses replace semantics. That is, if a 'route add' + * message for a prefix is followed by another 'route add' message, the + * information in the second message is complete by itself, and replaces + * the information sent in the first message. + * + * If the connection to the FPM goes down for some reason, the client + * (zebra) should send the FPM a complete copy of the forwarding + * table(s) when it reconnects. + */ + +#define FPM_DEFAULT_PORT 2620 + +/* + * Largest message that can be sent to or received from the FPM. + */ +#define FPM_MAX_MSG_LEN 4096 + +/* + * Header that precedes each fpm message to/from the FPM. + */ +typedef struct fpm_msg_hdr_t_ +{ + /* + * Protocol version. + */ + uint8_t version; + + /* + * Type of message, see below. + */ + uint8_t msg_type; + + /* + * Length of entire message, including the header, in network byte + * order. + * + * Note that msg_len is rounded up to make sure that message is at + * the desired alignment. This means that some payloads may need + * padding at the end. + */ + uint16_t msg_len; +} fpm_msg_hdr_t; + +/* + * The current version of the FPM protocol is 1. + */ +#define FPM_PROTO_VERSION 1 + +typedef enum fpm_msg_type_e_ { + FPM_MSG_TYPE_NONE = 0, + + /* + * Indicates that the payload is a completely formed netlink + * message. + */ + FPM_MSG_TYPE_NETLINK = 1, +} fpm_msg_type_e; + +/* + * The FPM message header is aligned to the same boundary as netlink + * messages (4). This means that a netlink message does not need + * padding when encapsulated in an FPM message. + */ +#define FPM_MSG_ALIGNTO 4 + +/* + * fpm_msg_align + * + * Round up the given length to the desired alignment. + */ +static inline size_t +fpm_msg_align (size_t len) +{ + return (len + FPM_MSG_ALIGNTO - 1) & ~(FPM_MSG_ALIGNTO - 1); +} + +/* + * The (rounded up) size of the FPM message header. This ensures that + * the message payload always starts at an aligned address. + */ +#define FPM_MSG_HDR_LEN (fpm_msg_align (sizeof (fpm_msg_hdr_t))) + +/* + * fpm_data_len_to_msg_len + * + * The length value that should be placed in the msg_len field of the + * header for a *payload* of size 'data_len'. + */ +static inline size_t +fpm_data_len_to_msg_len (size_t data_len) +{ + return fpm_msg_align (data_len) + FPM_MSG_HDR_LEN; +} + +/* + * fpm_msg_data + * + * Pointer to the payload of the given fpm header. + */ +static inline void * +fpm_msg_data (fpm_msg_hdr_t *hdr) +{ + return ((char*) hdr) + FPM_MSG_HDR_LEN; +} + +/* + * fpm_msg_len + */ +static inline size_t +fpm_msg_len (const fpm_msg_hdr_t *hdr) +{ + return ntohs (hdr->msg_len); +} + +/* + * fpm_msg_data_len + */ +static inline size_t +fpm_msg_data_len (const fpm_msg_hdr_t *hdr) +{ + return (fpm_msg_len (hdr) - FPM_MSG_HDR_LEN); +} + +/* + * fpm_msg_next + * + * Move to the next message in a buffer. + */ +static inline fpm_msg_hdr_t * +fpm_msg_next (fpm_msg_hdr_t *hdr, size_t *len) +{ + size_t msg_len; + + msg_len = fpm_msg_len (hdr); + + if (len) { + if (*len < msg_len) + { + assert(0); + return NULL; + } + *len -= msg_len; + } + + return (fpm_msg_hdr_t *) (((char*) hdr) + msg_len); +} + +/* + * fpm_msg_hdr_ok + * + * Returns TRUE if a message header looks well-formed. + */ +static inline int +fpm_msg_hdr_ok (const fpm_msg_hdr_t *hdr) +{ + size_t msg_len; + + if (hdr->msg_type == FPM_MSG_TYPE_NONE) + return 0; + + msg_len = fpm_msg_len (hdr); + + if (msg_len < FPM_MSG_HDR_LEN || msg_len > FPM_MAX_MSG_LEN) + return 0; + + if (fpm_msg_align (msg_len) != msg_len) + return 0; + + return 1; +} + +/* + * fpm_msg_ok + * + * Returns TRUE if a message looks well-formed. + * + * @param len The length in bytes from 'hdr' to the end of the buffer. + */ +static inline int +fpm_msg_ok (const fpm_msg_hdr_t *hdr, size_t len) +{ + if (len < FPM_MSG_HDR_LEN) + return 0; + + if (!fpm_msg_hdr_ok (hdr)) + return 0; + + if (fpm_msg_len (hdr) > len) + return 0; + + return 1; +} + +#endif /* _FPM_H */ |