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| | // 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_check_range() - Check if a memory range is valid for a pool
* @p: Packet pool
* @ptr: Start of desired data range
* @len: Length of desired data range
* @func: For tracing: name of calling function
* @line: For tracing: caller line of function call
*
* Return: 0 if the range is valid, -1 otherwise
*/
static int packet_check_range(const struct pool *p, const char *ptr, size_t len,
const char *func, int line)
{
if (len > PACKET_MAX_LEN) {
debug("packet range length %zu (max %zu), %s:%i",
len, PACKET_MAX_LEN, func, line);
return -1;
}
if (p->buf_size == 0) {
int ret;
ret = vu_packet_check_range((void *)p->buf, ptr, len);
if (ret == -1)
debug("cannot find region, %s:%i", func, line);
return ret;
}
if (ptr < p->buf) {
debug("packet range start %p before buffer start %p, %s:%i",
(void *)ptr, (void *)p->buf, func, line);
return -1;
}
if (len > p->buf_size) {
debug("packet range length %zu larger than buffer %zu, %s:%i",
len, p->buf_size, func, line);
return -1;
}
if ((size_t)(ptr - p->buf) > p->buf_size - len) {
debug("packet range %p, len %zu after buffer end %p, %s:%i",
(void *)ptr, len, (void *)(p->buf + p->buf_size),
func, line);
return -1;
}
return 0;
}
/**
* pool_full() - Is a packet pool full?
* @p: Pointer to packet pool
*
* Return: true if the pool is full, false if more packets can be added
*/
bool pool_full(const struct pool *p)
{
return p->count >= p->size;
}
/**
* packet_add_do() - Add data as packet descriptor to given pool
* @p: Existing pool
* @data: Data to add
* @func: For tracing: name of calling function
* @line: For tracing: caller line of function call
*/
void packet_add_do(struct pool *p, struct iov_tail *data,
const char *func, int line)
{
size_t idx = p->count;
const char *start;
size_t len;
if (pool_full(p)) {
debug("add packet index %zu to pool with size %zu, %s:%i",
idx, p->size, func, line);
return;
}
if (!iov_tail_prune(data))
return;
ASSERT(data->cnt == 1); /* we don't support iovec */
len = data->iov[0].iov_len - data->off;
start = (char *)data->iov[0].iov_base + data->off;
if (packet_check_range(p, start, len, func, line))
return;
p->pkt[idx].iov_base = (void *)start;
p->pkt[idx].iov_len = len;
p->count++;
}
/**
* packet_base_do() - Get data range from packet descriptor from given pool
* @p: Packet pool
* @idx: Index of packet descriptor in pool
* @data: IOV tail to store the address of the data (output)
* @func: For tracing: name of calling function, NULL means no trace()
* @line: For tracing: caller line of function call
*
* Return: true if @data contains valid data, false otherwise
*/
bool packet_base_do(const struct pool *p, size_t idx,
struct iov_tail *data,
const char *func, int line)
{
size_t i;
ASSERT_WITH_MSG(p->count <= p->size,
"Corrupt pool count: %zu, size: %zu, %s:%i",
p->count, p->size, func, line);
if (idx >= p->count) {
debug("packet %zu from pool size: %zu, count: %zu, "
"%s:%i", idx, p->size, p->count, func, line);
return false;
}
data->cnt = 1;
data->off = 0;
data->iov = &p->pkt[idx];
for (i = 0; i < data->cnt; i++) {
ASSERT_WITH_MSG(!packet_check_range(p, data->iov[i].iov_base,
data->iov[i].iov_len,
func, line),
"Corrupt packet pool, %s:%i", func, line);
}
return true;
}
/**
* pool_flush() - Flush a packet pool
* @p: Pointer to packet pool
*/
void pool_flush(struct pool *p)
{
p->count = 0;
}
|