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passt/packet.h
David Gibson 5b6c68c2e4 Avoid shadowing index(3)
A classic gotcha of the standard C library is that its unwise to call any
variable 'index' because it will shadow the standard string library
function index(3).  This can cause warnings from cppcheck amongst others,
and it also means that if the variable is removed you tend to get confusing
type errors (or sometimes nothing at all) instead of a nice simple "name is
not defined" error.

Strictly speaking this only occurs if <string.h> is included, but that
is so common that as a rule it's best to just avoid it always.  We
have a number of places which hit this trap, so rename variables and
parameters to avoid it.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2023-09-27 17:25:51 +02:00

83 lines
2.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright (c) 2022 Red Hat GmbH
* Author: Stefano Brivio <sbrivio@redhat.com>
*/
#ifndef PACKET_H
#define PACKET_H
/**
* struct desc - Generic offset-based descriptor within buffer
* @offset: Offset of descriptor relative to buffer start, 32-bit limit
* @len: Length of descriptor, host order, 16-bit limit
*/
struct desc {
uint32_t offset;
uint16_t len;
};
/**
* struct pool - Generic pool of packets stored in a buffer
* @buf: Buffer storing packet descriptors
* @buf_size: Total size of buffer
* @size: Number of usable descriptors for the pool
* @count: Number of used descriptors for the pool
* @pkt: Descriptors: see macros below
*/
struct pool {
char *buf;
size_t buf_size;
size_t size;
size_t count;
struct desc pkt[1];
};
void packet_add_do(struct pool *p, size_t len, const char *start,
const char *func, int line);
void *packet_get_do(const struct pool *p, const size_t idx,
size_t offset, size_t len, size_t *left,
const char *func, int line);
void pool_flush(struct pool *p);
#define packet_add(p, len, start) \
packet_add_do(p, len, start, __func__, __LINE__)
#define packet_get(p, idx, offset, len, left) \
packet_get_do(p, idx, offset, len, left, __func__, __LINE__)
#define packet_get_try(p, idx, offset, len, left) \
packet_get_do(p, idx, offset, len, left, NULL, 0)
#define PACKET_POOL_DECL(_name, _size, _buf) \
struct _name ## _t { \
char *buf; \
size_t buf_size; \
size_t size; \
size_t count; \
struct desc pkt[_size]; \
}
#define PACKET_POOL_INIT_NOCAST(_size, _buf, _buf_size) \
{ \
.buf_size = _buf_size, \
.buf = _buf, \
.size = _size, \
}
#define PACKET_POOL(name, size, buf, buf_size) \
PACKET_POOL_DECL(name, size, buf) name = \
PACKET_POOL_INIT_NOCAST(size, buf, buf_size)
#define PACKET_INIT(name, size, buf, buf_size) \
(struct name ## _t) PACKET_POOL_INIT_NOCAST(size, buf, buf_size)
#define PACKET_POOL_NOINIT(name, size, buf) \
PACKET_POOL_DECL(name, size, buf) name ## _storage; \
static struct pool *name = (struct pool *)&name ## _storage
#define PACKET_POOL_P(name, size, buf, buf_size) \
PACKET_POOL(name ## _storage, size, buf, buf_size); \
struct pool *name = (struct pool *)&name ## _storage
#endif /* PACKET_H */