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Diffstat (limited to '')
| -rw-r--r-- | lib/stream.h | 500 |
1 files changed, 500 insertions, 0 deletions
diff --git a/lib/stream.h b/lib/stream.h new file mode 100644 index 0000000..35733e7 --- /dev/null +++ b/lib/stream.h @@ -0,0 +1,500 @@ +/* + * 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 + * 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; see the file COPYING; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef _ZEBRA_STREAM_H +#define _ZEBRA_STREAM_H + +#include <pthread.h> + +#include "frratomic.h" +#include "mpls.h" +#include "prefix.h" + +#ifdef __cplusplus +extern "C" { +#endif + +/* + * 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: + * + * --------------------------------------------------- + * |XXXXXXXXXXXXXXXXXXXXXXXX | + * --------------------------------------------------- + * ^ ^ ^ + * 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[]; /* 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; +#endif + + 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 *); +/* Copy 'src' into 'dest', returns 'dest' */ +extern struct stream *stream_copy(struct stream *dest, + const struct stream *src); +extern struct stream *stream_dup(const struct stream *s); + +extern size_t stream_resize_inplace(struct stream **sptr, size_t newsize); + +extern size_t stream_get_getp(const struct stream *s); +extern size_t stream_get_endp(const struct stream *s); +extern size_t stream_get_size(const struct stream *s); + +/** + * 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(const struct stream *s1, + const 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 bool stream_forward_getp2(struct stream *, size_t); +extern void stream_rewind_getp(struct stream *s, size_t size); +extern bool stream_rewind_getp2(struct stream *s, size_t size); +extern void stream_forward_endp(struct stream *, size_t); +extern bool stream_forward_endp2(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 *s, const struct in_addr *addr); +extern bool stream_put_ipaddr(struct stream *s, struct ipaddr *ip); +extern int stream_put_in_addr_at(struct stream *s, size_t putp, + const struct in_addr *addr); +extern int stream_put_in6_addr_at(struct stream *s, size_t putp, + const struct in6_addr *addr); +extern int stream_put_prefix_addpath(struct stream *s, const struct prefix *p, + bool addpath_capable, + uint32_t addpath_tx_id); +extern int stream_put_prefix(struct stream *s, const struct prefix *p); +extern int stream_put_labeled_prefix(struct stream *, const struct prefix *, + mpls_label_t *, bool addpath_capable, + uint32_t addpath_tx_id); +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); +bool stream_getq2(struct stream *s, uint64_t *q); +extern uint32_t stream_get_ipv4(struct stream *); +extern bool stream_get_ipaddr(struct stream *s, struct ipaddr *ip); + +/* 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? */ + +/* debugging */ +extern void stream_hexdump(const struct stream *s); + +/** + * Reorganize the buffer data so it can fit more. This function is normally + * called right after stream data is consumed so we can read more data + * (the functions that consume data start with `stream_get*()` and macros + * `STREAM_GET*()`). + * + * \param s stream pointer. + */ +extern void stream_pulldown(struct stream *s); + +/* 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); + +/* + * Init or re-init an on-stack fifo. This allows use of a fifo struct without + * requiring a malloc/free cycle. + * Note well that the fifo must be de-inited with the 'fifo_deinit' api. + */ +void stream_fifo_init(struct stream_fifo *fifo); + +/* + * Deinit an on-stack fifo. + */ +void stream_fifo_deinit(struct stream_fifo *fifo); + +/* + * 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 const uint8_t *ptr_get_be32(const uint8_t *ptr, uint32_t *out) +{ + uint32_t tmp; + + memcpy(&tmp, ptr, sizeof(tmp)); + *out = ntohl(tmp); + return ptr + 4; +} + +static inline uint8_t *ptr_get_be16(uint8_t *ptr, uint16_t *out) +{ + uint16_t tmp; + + memcpy(&tmp, ptr, sizeof(tmp)); + *out = ntohs(tmp); + + return ptr + 2; +} + +/* + * 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_GETF(S, P) \ + do { \ + union { \ + float r; \ + uint32_t d; \ + } _pval; \ + if (!stream_getl2((S), &_pval.d)) \ + goto stream_failure; \ + (P) = _pval.r; \ + } while (0) + +#define STREAM_GETQ(S, P) \ + do { \ + uint64_t _pval; \ + if (!stream_getq2((S), &_pval)) \ + goto stream_failure; \ + (P) = _pval; \ + } while (0) + +#define STREAM_GET_IPADDR(S, P) \ + do { \ + if (!stream_get_ipaddr((S), (P))) \ + goto stream_failure; \ + } while (0) + +#define STREAM_GET(P, STR, SIZE) \ + do { \ + if (!stream_get2((P), (STR), (SIZE))) \ + goto stream_failure; \ + } while (0) + +#define STREAM_FORWARD_GETP(STR, SIZE) \ + do { \ + if (!stream_forward_getp2((STR), (SIZE))) \ + goto stream_failure; \ + } while (0) + +#define STREAM_REWIND_GETP(STR, SIZE) \ + do { \ + if (!stream_rewind_getp2((STR), (SIZE))) \ + goto stream_failure; \ + } while (0) + +#define STREAM_FORWARD_ENDP(STR, SIZE) \ + do { \ + if (!stream_forward_endp2((STR), (SIZE))) \ + goto stream_failure; \ + } while (0) + +#ifdef __cplusplus +} +#endif + +#endif /* _ZEBRA_STREAM_H */ |