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passt/packet.h
David Gibson c48331ca51 packet: Correct type of PACKET_MAX_LEN
PACKET_MAX_LEN is usually involved in calculations on size_t values - the
type of the iov_len field in struct iovec.  However, being defined bare as
UINT16_MAX, the compiled is likely to assign it a shorter type.  This can
lead to unexpected promotions (or lack thereof).  Add a cast to force the
type to be what we expect.

Fixes: c43972ad6 ("packet: Give explicit name to maximum packet size")
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2025-03-20 20:33:15 +01:00

81 lines
2.4 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
#include <stdbool.h>
/* Maximum size of a single packet stored in pool, including headers */
#define PACKET_MAX_LEN ((size_t)UINT16_MAX)
/**
* struct pool - Generic pool of packets stored in a buffer
* @buf: Buffer storing packet descriptors,
* a struct vu_dev_region array for passt vhost-user mode
* @buf_size: Total size of buffer,
* 0 for passt vhost-user mode
* @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 iovec pkt[];
};
int vu_packet_check_range(void *buf, const char *ptr, size_t len);
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);
bool pool_full(const struct pool *p);
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 iovec 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 */