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412 lines
14 KiB
C
412 lines
14 KiB
C
/*
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* Packet interface
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* Copyright (C) 1999 Kunihiro Ishiguro
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*
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* This file is part of GNU Zebra.
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*
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* GNU Zebra is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2, or (at your option) any
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* later version.
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*
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* GNU Zebra is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; see the file COPYING; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef _ZEBRA_STREAM_H
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#define _ZEBRA_STREAM_H
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#include <pthread.h>
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#include "frratomic.h"
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#include "mpls.h"
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#include "prefix.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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* A stream is an arbitrary buffer, whose contents generally are assumed to
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* be in network order.
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*
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* A stream has the following attributes associated with it:
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*
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* - size: the allocated, invariant size of the buffer.
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*
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* - getp: the get position marker, denoting the offset in the stream where
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* the next read (or 'get') will be from. This getp marker is
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* automatically adjusted when data is read from the stream, the
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* user may also manipulate this offset as they wish, within limits
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* (see below)
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*
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* - endp: the end position marker, denoting the offset in the stream where
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* valid data ends, and if the user attempted to write (or
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* 'put') data where that data would be written (or 'put') to.
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*
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* These attributes are all size_t values.
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*
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* Constraints:
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*
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* 1. getp can never exceed endp
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*
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* - hence if getp is equal to endp, there is no more valid data that can be
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* gotten from the stream (though, the user may reposition getp to earlier in
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* the stream, if they wish).
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*
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* 2. endp can never exceed size
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*
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* - hence, if endp is equal to size, then the stream is full, and no more
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* data can be written to the stream.
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*
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* In other words the following must always be true, and the stream
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* abstraction is allowed internally to assert that the following property
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* holds true for a stream, as and when it wishes:
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*
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* getp <= endp <= size
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*
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* It is the users responsibility to ensure this property is never violated.
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*
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* A stream therefore can be thought of like this:
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*
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* ---------------------------------------------------
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* |XXXXXXXXXXXXXXXXXXXXXXXX |
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* ---------------------------------------------------
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* ^ ^ ^
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* getp endp size
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*
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* This shows a stream containing data (shown as 'X') up to the endp offset.
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* The stream is empty from endp to size. Without adjusting getp, there are
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* still endp-getp bytes of valid data to be read from the stream.
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*
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* Methods are provided to get and put to/from the stream, as well as
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* retrieve the values of the 3 markers and manipulate the getp marker.
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*
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* Note:
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* At the moment, newly allocated streams are zero filled. Hence, one can
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* use stream_forward_endp() to effectively create arbitrary zero-fill
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* padding. However, note that stream_reset() does *not* zero-out the
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* stream. This property should **not** be relied upon.
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*
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* Best practice is to use stream_put (<stream *>, NULL, <size>) to zero out
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* any part of a stream which isn't otherwise written to.
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*/
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/* Stream buffer. */
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struct stream {
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struct stream *next;
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/*
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* Remainder is ***private*** to stream
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* direct access is frowned upon!
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* Use the appropriate functions/macros
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*/
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size_t getp; /* next get position */
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size_t endp; /* last valid data position */
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size_t size; /* size of data segment */
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unsigned char data[0]; /* data pointer */
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};
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/* First in first out queue structure. */
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struct stream_fifo {
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/* lock for mt-safe operations */
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pthread_mutex_t mtx;
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/* number of streams in this fifo */
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atomic_size_t count;
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#if defined DEV_BUILD
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atomic_size_t max_count;
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#endif
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struct stream *head;
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struct stream *tail;
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};
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/* Utility macros. */
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#define STREAM_SIZE(S) ((S)->size)
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/* number of bytes which can still be written */
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#define STREAM_WRITEABLE(S) ((S)->size - (S)->endp)
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/* number of bytes still to be read */
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#define STREAM_READABLE(S) ((S)->endp - (S)->getp)
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#define STREAM_CONCAT_REMAIN(S1, S2, size) ((size) - (S1)->endp - (S2)->endp)
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/* this macro is deprecated, but not slated for removal anytime soon */
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#define STREAM_DATA(S) ((S)->data)
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/* Stream prototypes.
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* For stream_{put,get}S, the S suffix mean:
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*
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* c: character (unsigned byte)
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* w: word (two bytes)
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* l: long (two words)
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* q: quad (four words)
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*/
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extern struct stream *stream_new(size_t);
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extern void stream_free(struct stream *);
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extern struct stream *stream_copy(struct stream *, struct stream *src);
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extern struct stream *stream_dup(struct stream *);
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extern size_t stream_resize_inplace(struct stream **sptr, size_t newsize);
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extern size_t stream_get_getp(struct stream *);
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extern size_t stream_get_endp(struct stream *);
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extern size_t stream_get_size(struct stream *);
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extern uint8_t *stream_get_data(struct stream *);
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/**
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* Create a new stream structure; copy offset bytes from s1 to the new
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* stream; copy s2 data to the new stream; copy rest of s1 data to the
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* new stream.
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*/
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extern struct stream *stream_dupcat(struct stream *s1, struct stream *s2,
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size_t offset);
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extern void stream_set_getp(struct stream *, size_t);
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extern void stream_set_endp(struct stream *, size_t);
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extern void stream_forward_getp(struct stream *, size_t);
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extern void stream_forward_endp(struct stream *, size_t);
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/* steam_put: NULL source zeroes out size_t bytes of stream */
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extern void stream_put(struct stream *, const void *, size_t);
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extern int stream_putc(struct stream *, uint8_t);
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extern int stream_putc_at(struct stream *, size_t, uint8_t);
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extern int stream_putw(struct stream *, uint16_t);
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extern int stream_putw_at(struct stream *, size_t, uint16_t);
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extern int stream_put3(struct stream *, uint32_t);
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extern int stream_put3_at(struct stream *, size_t, uint32_t);
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extern int stream_putl(struct stream *, uint32_t);
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extern int stream_putl_at(struct stream *, size_t, uint32_t);
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extern int stream_putq(struct stream *, uint64_t);
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extern int stream_putq_at(struct stream *, size_t, uint64_t);
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extern int stream_put_ipv4(struct stream *, uint32_t);
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extern int stream_put_in_addr(struct stream *, struct in_addr *);
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extern int stream_put_in_addr_at(struct stream *, size_t, struct in_addr *);
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extern int stream_put_in6_addr_at(struct stream *, size_t, struct in6_addr *);
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extern int stream_put_prefix_addpath(struct stream *, struct prefix *,
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int addpath_encode,
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uint32_t addpath_tx_id);
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extern int stream_put_prefix(struct stream *, struct prefix *);
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extern int stream_put_labeled_prefix(struct stream *, struct prefix *,
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mpls_label_t *, int addpath_encode,
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uint32_t addpath_tx_id);
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extern void stream_get(void *, struct stream *, size_t);
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extern bool stream_get2(void *data, struct stream *s, size_t size);
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extern void stream_get_from(void *, struct stream *, size_t, size_t);
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extern uint8_t stream_getc(struct stream *);
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extern bool stream_getc2(struct stream *s, uint8_t *byte);
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extern uint8_t stream_getc_from(struct stream *, size_t);
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extern uint16_t stream_getw(struct stream *);
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extern bool stream_getw2(struct stream *s, uint16_t *word);
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extern uint16_t stream_getw_from(struct stream *, size_t);
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extern uint32_t stream_get3(struct stream *);
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extern uint32_t stream_get3_from(struct stream *, size_t);
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extern uint32_t stream_getl(struct stream *);
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extern bool stream_getl2(struct stream *s, uint32_t *l);
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extern uint32_t stream_getl_from(struct stream *, size_t);
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extern uint64_t stream_getq(struct stream *);
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extern uint64_t stream_getq_from(struct stream *, size_t);
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extern uint32_t stream_get_ipv4(struct stream *);
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/* IEEE-754 floats */
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extern float stream_getf(struct stream *);
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extern double stream_getd(struct stream *);
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extern int stream_putf(struct stream *, float);
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extern int stream_putd(struct stream *, double);
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#undef stream_read
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#undef stream_write
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/* Deprecated: assumes blocking I/O. Will be removed.
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Use stream_read_try instead. */
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extern int stream_read(struct stream *, int, size_t);
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/* Read up to size bytes into the stream.
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Return code:
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>0: number of bytes read
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0: end-of-file
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-1: fatal error
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-2: transient error, should retry later (i.e. EAGAIN or EINTR)
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This is suitable for use with non-blocking file descriptors.
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*/
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extern ssize_t stream_read_try(struct stream *s, int fd, size_t size);
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extern ssize_t stream_recvmsg(struct stream *s, int fd, struct msghdr *,
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int flags, size_t size);
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extern ssize_t stream_recvfrom(struct stream *s, int fd, size_t len, int flags,
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struct sockaddr *from, socklen_t *fromlen);
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extern size_t stream_write(struct stream *, const void *, size_t);
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/* reset the stream. See Note above */
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extern void stream_reset(struct stream *);
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extern int stream_flush(struct stream *, int);
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extern int stream_empty(struct stream *); /* is the stream empty? */
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/* deprecated */
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extern uint8_t *stream_pnt(struct stream *);
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/*
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* Operations on struct stream_fifo.
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*
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* Each function has a safe variant, which ensures that the operation performed
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* is atomic with respect to the operations performed by all other safe
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* variants. In other words, the safe variants lock the stream_fifo's mutex
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* before performing their action. These are provided for convenience when
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* using stream_fifo in a multithreaded context, to alleviate the need for the
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* caller to implement their own synchronization around the stream_fifo.
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*
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* The following functions do not have safe variants. The caller must ensure
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* that these operations are performed safely in a multithreaded context:
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* - stream_fifo_new
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* - stream_fifo_free
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*/
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/*
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* Create a new stream_fifo.
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*
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* Returns:
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* newly created stream_fifo
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*/
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extern struct stream_fifo *stream_fifo_new(void);
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/*
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* Push a stream onto a stream_fifo.
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*
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* fifo
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* the stream_fifo to push onto
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*
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* s
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* the stream to push onto the stream_fifo
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*/
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extern void stream_fifo_push(struct stream_fifo *fifo, struct stream *s);
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extern void stream_fifo_push_safe(struct stream_fifo *fifo, struct stream *s);
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/*
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* Pop a stream off a stream_fifo.
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*
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* fifo
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* the stream_fifo to pop from
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*
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* Returns:
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* the next stream in the stream_fifo
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*/
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extern struct stream *stream_fifo_pop(struct stream_fifo *fifo);
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extern struct stream *stream_fifo_pop_safe(struct stream_fifo *fifo);
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/*
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* Retrieve the next stream from a stream_fifo without popping it.
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*
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* fifo
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* the stream_fifo to operate on
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*
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* Returns:
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* the next stream that would be returned from stream_fifo_pop
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*/
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extern struct stream *stream_fifo_head(struct stream_fifo *fifo);
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extern struct stream *stream_fifo_head_safe(struct stream_fifo *fifo);
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/*
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* Remove all streams from a stream_fifo.
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*
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* fifo
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* the stream_fifo to clean
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*/
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extern void stream_fifo_clean(struct stream_fifo *fifo);
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extern void stream_fifo_clean_safe(struct stream_fifo *fifo);
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/*
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* Retrieve number of streams on a stream_fifo.
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*
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* fifo
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* the stream_fifo to retrieve the count for
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*
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* Returns:
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* the number of streams on the stream_fifo
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*/
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extern size_t stream_fifo_count_safe(struct stream_fifo *fifo);
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/*
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* Free a stream_fifo.
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*
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* Calls stream_fifo_clean, then deinitializes the stream_fifo and frees it.
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*
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* fifo
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* the stream_fifo to free
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*/
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extern void stream_fifo_free(struct stream_fifo *fifo);
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/* This is here because "<< 24" is particularly problematic in C.
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* This is because the left operand of << is integer-promoted, which means
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* an uint8_t gets converted into a *signed* int. Shifting into the sign
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* bit of a signed int is theoretically undefined behaviour, so - the left
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* operand needs to be cast to unsigned.
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*
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* This is not a problem for 16- or 8-bit values (they don't reach the sign
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* bit), for 64-bit values (you need to cast them anyway), and neither for
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* encoding (because it's downcasted.)
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*/
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static inline uint8_t *ptr_get_be32(uint8_t *ptr, uint32_t *out)
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{
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uint32_t tmp;
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memcpy(&tmp, ptr, sizeof(tmp));
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*out = ntohl(tmp);
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return ptr + 4;
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}
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/*
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* so Normal stream_getX functions assert. Which is anathema
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* to keeping a daemon up and running when something goes south
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* Provide a stream_getX2 functions that do not assert.
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* In addition provide these macro's that upon failure
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* goto stream_failure. This is modeled upon some NL_XX
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* macros in the linux kernel.
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*
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* This change allows for proper memory freeing
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* after we've detected an error.
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*
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* In the future we will be removing the assert in
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* the stream functions but we need a transition
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* plan.
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*/
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#define STREAM_GETC(S, P) \
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do { \
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uint8_t _pval; \
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if (!stream_getc2((S), &_pval)) \
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goto stream_failure; \
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(P) = _pval; \
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} while (0)
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#define STREAM_GETW(S, P) \
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do { \
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uint16_t _pval; \
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if (!stream_getw2((S), &_pval)) \
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goto stream_failure; \
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(P) = _pval; \
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} while (0)
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#define STREAM_GETL(S, P) \
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do { \
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uint32_t _pval; \
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if (!stream_getl2((S), &_pval)) \
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goto stream_failure; \
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(P) = _pval; \
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} while (0)
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#define STREAM_GET(P, STR, SIZE) \
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do { \
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if (!stream_get2((P), (STR), (SIZE))) \
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goto stream_failure; \
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} while (0)
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#ifdef __cplusplus
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}
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#endif
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#endif /* _ZEBRA_STREAM_H */
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