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* Packet interface
* Copyright (C) 1999 Kunihiro Ishiguro
* This file is part of GNU Zebra.
* GNU Zebra 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, or (at your option) any
* later version.
* GNU Zebra is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* General Public License for more details.
* You should have received a copy of the GNU General Public License along
* with this program; see the file COPYING; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#include <pthread.h>
#include "frratomic.h"
#include "mpls.h"
#include "prefix.h"
#ifdef __cplusplus
extern "C" {
* A stream is an arbitrary buffer, whose contents generally are assumed to
* be in network order.
* A stream has the following attributes associated with it:
* - size: the allocated, invariant size of the buffer.
* - getp: the get position marker, denoting the offset in the stream where
* the next read (or 'get') will be from. This getp marker is
* automatically adjusted when data is read from the stream, the
* user may also manipulate this offset as they wish, within limits
* (see below)
* - endp: the end position marker, denoting the offset in the stream where
* valid data ends, and if the user attempted to write (or
* 'put') data where that data would be written (or 'put') to.
* These attributes are all size_t values.
* Constraints:
* 1. getp can never exceed endp
* - hence if getp is equal to endp, there is no more valid data that can be
* gotten from the stream (though, the user may reposition getp to earlier in
* the stream, if they wish).
* 2. endp can never exceed size
* - hence, if endp is equal to size, then the stream is full, and no more
* data can be written to the stream.
* In other words the following must always be true, and the stream
* abstraction is allowed internally to assert that the following property
* holds true for a stream, as and when it wishes:
* getp <= endp <= size
* It is the users responsibility to ensure this property is never violated.
* A stream therefore can be thought of like this:
* ---------------------------------------------------
* ---------------------------------------------------
* ^ ^ ^
* getp endp size
* This shows a stream containing data (shown as 'X') up to the endp offset.
* The stream is empty from endp to size. Without adjusting getp, there are
* still endp-getp bytes of valid data to be read from the stream.
* Methods are provided to get and put to/from the stream, as well as
* retrieve the values of the 3 markers and manipulate the getp marker.
* Note:
* At the moment, newly allocated streams are zero filled. Hence, one can
* use stream_forward_endp() to effectively create arbitrary zero-fill
* padding. However, note that stream_reset() does *not* zero-out the
* stream. This property should **not** be relied upon.
* Best practice is to use stream_put (<stream *>, NULL, <size>) to zero out
* any part of a stream which isn't otherwise written to.
/* Stream buffer. */
struct stream {
struct stream *next;
* Remainder is ***private*** to stream
* direct access is frowned upon!
* Use the appropriate functions/macros
size_t getp; /* next get position */
size_t endp; /* last valid data position */
size_t size; /* size of data segment */
unsigned char data[0]; /* data pointer */
/* First in first out queue structure. */
struct stream_fifo {
/* lock for mt-safe operations */
pthread_mutex_t mtx;
/* number of streams in this fifo */
atomic_size_t count;
#if defined DEV_BUILD
atomic_size_t max_count;
struct stream *head;
struct stream *tail;
/* Utility macros. */
#define STREAM_SIZE(S) ((S)->size)
/* number of bytes which can still be written */
#define STREAM_WRITEABLE(S) ((S)->size - (S)->endp)
/* number of bytes still to be read */
#define STREAM_READABLE(S) ((S)->endp - (S)->getp)
#define STREAM_CONCAT_REMAIN(S1, S2, size) ((size) - (S1)->endp - (S2)->endp)
/* this macro is deprecated, but not slated for removal anytime soon */
#define STREAM_DATA(S) ((S)->data)
/* Stream prototypes.
* For stream_{put,get}S, the S suffix mean:
* c: character (unsigned byte)
* w: word (two bytes)
* l: long (two words)
* q: quad (four words)
extern struct stream *stream_new(size_t);
extern void stream_free(struct stream *);
extern struct stream *stream_copy(struct stream *, struct stream *src);
extern struct stream *stream_dup(struct stream *);
#if CONFDATE > 20190821
CPP_NOTICE("lib: time to remove stream_resize_orig")
extern size_t stream_resize_orig(struct stream *s, size_t newsize);
#define stream_resize stream_resize_orig
extern size_t stream_resize_inplace(struct stream **sptr, size_t newsize);
extern size_t stream_get_getp(struct stream *);
extern size_t stream_get_endp(struct stream *);
extern size_t stream_get_size(struct stream *);
extern uint8_t *stream_get_data(struct stream *);
* Create a new stream structure; copy offset bytes from s1 to the new
* stream; copy s2 data to the new stream; copy rest of s1 data to the
* new stream.
extern struct stream *stream_dupcat(struct stream *s1, struct stream *s2,
size_t offset);
extern void stream_set_getp(struct stream *, size_t);
extern void stream_set_endp(struct stream *, size_t);
extern void stream_forward_getp(struct stream *, size_t);
extern void stream_forward_endp(struct stream *, size_t);
/* steam_put: NULL source zeroes out size_t bytes of stream */
extern void stream_put(struct stream *, const void *, size_t);
extern int stream_putc(struct stream *, uint8_t);
extern int stream_putc_at(struct stream *, size_t, uint8_t);
extern int stream_putw(struct stream *, uint16_t);
extern int stream_putw_at(struct stream *, size_t, uint16_t);
extern int stream_put3(struct stream *, uint32_t);
extern int stream_put3_at(struct stream *, size_t, uint32_t);
extern int stream_putl(struct stream *, uint32_t);
extern int stream_putl_at(struct stream *, size_t, uint32_t);
extern int stream_putq(struct stream *, uint64_t);
extern int stream_putq_at(struct stream *, size_t, uint64_t);
extern int stream_put_ipv4(struct stream *, uint32_t);
extern int stream_put_in_addr(struct stream *, struct in_addr *);
extern int stream_put_in_addr_at(struct stream *, size_t, struct in_addr *);
extern int stream_put_in6_addr_at(struct stream *, size_t, struct in6_addr *);
extern int stream_put_prefix_addpath(struct stream *, struct prefix *,
int addpath_encode,
uint32_t addpath_tx_id);
extern int stream_put_prefix(struct stream *, struct prefix *);
extern int stream_put_labeled_prefix(struct stream *, struct prefix *,
mpls_label_t *);
extern void stream_get(void *, struct stream *, size_t);
extern bool stream_get2(void *data, struct stream *s, size_t size);
extern void stream_get_from(void *, struct stream *, size_t, size_t);
extern uint8_t stream_getc(struct stream *);
extern bool stream_getc2(struct stream *s, uint8_t *byte);
extern uint8_t stream_getc_from(struct stream *, size_t);
extern uint16_t stream_getw(struct stream *);
extern bool stream_getw2(struct stream *s, uint16_t *word);
extern uint16_t stream_getw_from(struct stream *, size_t);
extern uint32_t stream_get3(struct stream *);
extern uint32_t stream_get3_from(struct stream *, size_t);
extern uint32_t stream_getl(struct stream *);
extern bool stream_getl2(struct stream *s, uint32_t *l);
extern uint32_t stream_getl_from(struct stream *, size_t);
extern uint64_t stream_getq(struct stream *);
extern uint64_t stream_getq_from(struct stream *, size_t);
extern uint32_t stream_get_ipv4(struct stream *);
/* IEEE-754 floats */
extern float stream_getf(struct stream *);
extern double stream_getd(struct stream *);
extern int stream_putf(struct stream *, float);
extern int stream_putd(struct stream *, double);
#undef stream_read
#undef stream_write
/* Deprecated: assumes blocking I/O. Will be removed.
Use stream_read_try instead. */
extern int stream_read(struct stream *, int, size_t);
/* Read up to size bytes into the stream.
Return code:
>0: number of bytes read
0: end-of-file
-1: fatal error
-2: transient error, should retry later (i.e. EAGAIN or EINTR)
This is suitable for use with non-blocking file descriptors.
extern ssize_t stream_read_try(struct stream *s, int fd, size_t size);
extern ssize_t stream_recvmsg(struct stream *s, int fd, struct msghdr *,
int flags, size_t size);
extern ssize_t stream_recvfrom(struct stream *s, int fd, size_t len, int flags,
struct sockaddr *from, socklen_t *fromlen);
extern size_t stream_write(struct stream *, const void *, size_t);
/* reset the stream. See Note above */
extern void stream_reset(struct stream *);
extern int stream_flush(struct stream *, int);
extern int stream_empty(struct stream *); /* is the stream empty? */
/* deprecated */
extern uint8_t *stream_pnt(struct stream *);
* Operations on struct stream_fifo.
* Each function has a safe variant, which ensures that the operation performed
* is atomic with respect to the operations performed by all other safe
* variants. In other words, the safe variants lock the stream_fifo's mutex
* before performing their action. These are provided for convenience when
* using stream_fifo in a multithreaded context, to alleviate the need for the
* caller to implement their own synchronization around the stream_fifo.
* The following functions do not have safe variants. The caller must ensure
* that these operations are performed safely in a multithreaded context:
* - stream_fifo_new
* - stream_fifo_free
* Create a new stream_fifo.
* Returns:
* newly created stream_fifo
extern struct stream_fifo *stream_fifo_new(void);
* Push a stream onto a stream_fifo.
* fifo
* the stream_fifo to push onto
* s
* the stream to push onto the stream_fifo
extern void stream_fifo_push(struct stream_fifo *fifo, struct stream *s);
extern void stream_fifo_push_safe(struct stream_fifo *fifo, struct stream *s);
* Pop a stream off a stream_fifo.
* fifo
* the stream_fifo to pop from
* Returns:
* the next stream in the stream_fifo
extern struct stream *stream_fifo_pop(struct stream_fifo *fifo);
extern struct stream *stream_fifo_pop_safe(struct stream_fifo *fifo);
* Retrieve the next stream from a stream_fifo without popping it.
* fifo
* the stream_fifo to operate on
* Returns:
* the next stream that would be returned from stream_fifo_pop
extern struct stream *stream_fifo_head(struct stream_fifo *fifo);
extern struct stream *stream_fifo_head_safe(struct stream_fifo *fifo);
* Remove all streams from a stream_fifo.
* fifo
* the stream_fifo to clean
extern void stream_fifo_clean(struct stream_fifo *fifo);
extern void stream_fifo_clean_safe(struct stream_fifo *fifo);
* Retrieve number of streams on a stream_fifo.
* fifo
* the stream_fifo to retrieve the count for
* Returns:
* the number of streams on the stream_fifo
extern size_t stream_fifo_count_safe(struct stream_fifo *fifo);
* Free a stream_fifo.
* Calls stream_fifo_clean, then deinitializes the stream_fifo and frees it.
* fifo
* the stream_fifo to free
extern void stream_fifo_free(struct stream_fifo *fifo);
/* This is here because "<< 24" is particularly problematic in C.
* This is because the left operand of << is integer-promoted, which means
* an uint8_t gets converted into a *signed* int. Shifting into the sign
* bit of a signed int is theoretically undefined behaviour, so - the left
* operand needs to be cast to unsigned.
* This is not a problem for 16- or 8-bit values (they don't reach the sign
* bit), for 64-bit values (you need to cast them anyway), and neither for
* encoding (because it's downcasted.)
static inline uint8_t *ptr_get_be32(uint8_t *ptr, uint32_t *out)
uint32_t tmp;
memcpy(&tmp, ptr, sizeof(tmp));
*out = ntohl(tmp);
return ptr + 4;
* so Normal stream_getX functions assert. Which is anathema
* to keeping a daemon up and running when something goes south
* Provide a stream_getX2 functions that do not assert.
* In addition provide these macro's that upon failure
* goto stream_failure. This is modeled upon some NL_XX
* macros in the linux kernel.
* This change allows for proper memory freeing
* after we've detected an error.
* In the future we will be removing the assert in
* the stream functions but we need a transition
* plan.
#define STREAM_GETC(S, P) \
do { \
uint8_t _pval; \
if (!stream_getc2((S), &_pval)) \
goto stream_failure; \
(P) = _pval; \
} while (0)
#define STREAM_GETW(S, P) \
do { \
uint16_t _pval; \
if (!stream_getw2((S), &_pval)) \
goto stream_failure; \
(P) = _pval; \
} while (0)
#define STREAM_GETL(S, P) \
do { \
uint32_t _pval; \
if (!stream_getl2((S), &_pval)) \
goto stream_failure; \
(P) = _pval; \
} while (0)
#define STREAM_GET(P, STR, SIZE) \
do { \
if (!stream_get2((P), (STR), (SIZE))) \
goto stream_failure; \
} while (0)
#ifdef __cplusplus
#endif /* _ZEBRA_STREAM_H */
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