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Diffstat (limited to 'fpm/fpm.h')
| -rw-r--r-- | fpm/fpm.h | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/fpm/fpm.h b/fpm/fpm.h new file mode 100644 index 0000000..b08310f --- /dev/null +++ b/fpm/fpm.h @@ -0,0 +1,269 @@ +// SPDX-License-Identifier: ISC OR GPL-2.0-or-later +/* + * 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 + * License Option 2: ISC License + */ + +#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. + */ + +/* + * Local host as a default server for fpm connection + */ +#define FPM_DEFAULT_IP (htonl (INADDR_LOOPBACK)) + +/* + * default port for fpm connections + */ +#define FPM_DEFAULT_PORT 2620 + +/* + * Largest message that can be sent to or received from the FPM. + */ +#define FPM_MAX_MSG_LEN 4096 + +#ifdef __SUNPRO_C +#pragma pack(1) +#endif + +/* + * 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. + */ + uint16_t msg_len; +} __attribute__((packed)) fpm_msg_hdr_t; + +#ifdef __SUNPRO_C +#pragma pack() +#endif + +/* + * 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. + * + * XXX Netlink cares about the alignment of messages. When any + * FPM_MSG_TYPE_NETLINK messages are sent over a channel, then all + * messages should be sized such that netlink alignment is + * maintained. + */ + FPM_MSG_TYPE_NETLINK = 1, + FPM_MSG_TYPE_PROTOBUF = 2, +} 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. + * + * **NB**: Alignment is required only when netlink messages are used. + */ +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 (sizeof(fpm_msg_hdr_t)) + +#ifndef COMPILE_ASSERT +#define COMPILE_ASSERT(x) extern int __dummy[2 * !!(x) - 1] +#endif + +COMPILE_ASSERT(FPM_MSG_ALIGNTO == FPM_MSG_HDR_LEN); + +/* + * 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 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; + + /* + * Netlink messages must be aligned properly. + */ + if (hdr->msg_type == FPM_MSG_TYPE_NETLINK + && 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; +} + +// tcp maximum range +#define TCP_MAX_PORT 65535 + +// tcp minimum range +#define TCP_MIN_PORT 1 + +#endif /* _FPM_H */ |