passt/packet.c
David Gibson 5972203174 log: Enable format warnings
logmsg() takes printf like arguments, but because it's not a built in, the
compiler won't generate warnings if the format string and parameters don't
match.  Enable those by using the format attribute.

Strictly speaking this is a gcc extension, but I believe it is also
supported by some other common compilers.  We already use some other
attributes in various places.  For now, just use it and we can worry about
compilers that don't support it if it comes up.

This exposes some warnings from existing callers, both in gcc and in
clang-tidy:
 - Some are straight out bugs, which we correct
 - It's occasionally useful to invoke the logging functions with an empty
   string, which gcc objects to, so disable that specific warning in the
   Makefile
 - Strictly speaking the C standard requires that the parameter for a %p
   be a (void *), not some other pointer type.  That's only likely to cause
   problems in practice on weird architectures with different sized
   representations for pointers to different types.  Nonetheless add the
   casts to make it happy.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2023-11-07 09:54:56 +01:00

138 lines
3.4 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* PASST - Plug A Simple Socket Transport
* for qemu/UNIX domain socket mode
*
* PASTA - Pack A Subtle Tap Abstraction
* for network namespace/tap device mode
*
* packet.c - Packet abstraction: add packets to pool, flush, get packet data
*
* Copyright (c) 2020-2021 Red Hat GmbH
* Author: Stefano Brivio <sbrivio@redhat.com>
*/
#include <limits.h>
#include <stddef.h>
#include <stdint.h>
#include <netinet/ip6.h>
#include "packet.h"
#include "util.h"
#include "log.h"
/**
* packet_add_do() - Add data as packet descriptor to given pool
* @p: Existing pool
* @len: Length of new descriptor
* @start: Start of data
* @func: For tracing: name of calling function, NULL means no trace()
* @line: For tracing: caller line of function call
*/
void packet_add_do(struct pool *p, size_t len, const char *start,
const char *func, int line)
{
size_t idx = p->count;
if (idx >= p->size) {
trace("add packet index %lu to pool with size %lu, %s:%i",
idx, p->size, func, line);
return;
}
if (start < p->buf) {
trace("add packet start %p before buffer start %p, %s:%i",
(void *)start, (void *)p->buf, func, line);
return;
}
if (start + len > p->buf + p->buf_size) {
trace("add packet start %p, length: %lu, buffer end %p, %s:%i",
(void *)start, len, (void *)(p->buf + p->buf_size),
func, line);
return;
}
if (len > UINT16_MAX) {
trace("add packet length %lu, %s:%i", len, func, line);
return;
}
#if UINTPTR_MAX == UINT64_MAX
if ((uintptr_t)start - (uintptr_t)p->buf > UINT32_MAX) {
trace("add packet start %p, buffer start %p, %s:%i",
(void *)start, (void *)p->buf, func, line);
return;
}
#endif
p->pkt[idx].offset = start - p->buf;
p->pkt[idx].len = len;
p->count++;
}
/**
* packet_get_do() - Get data range from packet descriptor from given pool
* @p: Packet pool
* @idx: Index of packet descriptor in pool
* @offset: Offset of data range in packet descriptor
* @len: Length of desired data range
* @left: Length of available data after range, set on return, can be NULL
* @func: For tracing: name of calling function, NULL means no trace()
* @line: For tracing: caller line of function call
*
* Return: pointer to start of data range, NULL on invalid range or descriptor
*/
void *packet_get_do(const struct pool *p, size_t idx, size_t offset,
size_t len, size_t *left, const char *func, int line)
{
if (idx >= p->size || idx >= p->count) {
if (func) {
trace("packet %lu from pool size: %lu, count: %lu, "
"%s:%i", idx, p->size, p->count, func, line);
}
return NULL;
}
if (len > UINT16_MAX || len + offset > UINT32_MAX) {
if (func) {
trace("packet data length %lu, offset %lu, %s:%i",
len, offset, func, line);
}
return NULL;
}
if (p->pkt[idx].offset + len + offset > p->buf_size) {
if (func) {
trace("packet offset plus length %lu from size %lu, "
"%s:%i", p->pkt[idx].offset + len + offset,
p->buf_size, func, line);
}
return NULL;
}
if (len + offset > p->pkt[idx].len) {
if (func) {
trace("data length %lu, offset %lu from length %u, "
"%s:%i", len, offset, p->pkt[idx].len,
func, line);
}
return NULL;
}
if (left)
*left = p->pkt[idx].len - offset - len;
return p->buf + p->pkt[idx].offset + offset;
}
/**
* pool_flush() - Flush a packet pool
* @p: Pointer to packet pool
*/
void pool_flush(struct pool *p)
{
p->count = 0;
}