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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 packet memory range is valid
* @p: Packet pool
* @offset: Offset of data range in packet descriptor
* @len: Length of desired data range
* @start: Start of the packet descriptor
* @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, size_t offset, size_t len,
const char *start, const char *func, int line)
{
if (start < p->buf) {
trace("packet start %p before buffer start %p, "
"%s:%i", (void *)start, (void *)p->buf, func, line);
return -1;
}
if (start + len + offset > p->buf + p->buf_size) {
trace("packet offset plus length %lu from size %lu, "
"%s:%i", start - p->buf + len + offset,
p->buf_size, func, line);
return -1;
}
return 0;
}
/**
* 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 %zu to pool with size %zu, %s:%i",
idx, p->size, func, line);
return;
}
if (packet_check_range(p, 0, len, start, func, line))
return;
if (len > UINT16_MAX) {
trace("add packet length %zu, %s:%i", len, func, line);
return;
}
p->pkt[idx].iov_base = (void *)start;
p->pkt[idx].iov_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 %zu from pool size: %zu, count: %zu, "
"%s:%i", idx, p->size, p->count, func, line);
}
return NULL;
}
if (len > UINT16_MAX) {
if (func) {
trace("packet data length %zu, %s:%i",
len, func, line);
}
return NULL;
}
if (len + offset > p->pkt[idx].iov_len) {
if (func) {
trace("data length %zu, offset %zu from length %zu, "
"%s:%i", len, offset, p->pkt[idx].iov_len,
func, line);
}
return NULL;
}
if (packet_check_range(p, offset, len, p->pkt[idx].iov_base,
func, line))
return NULL;
if (left)
*left = p->pkt[idx].iov_len - offset - len;
return (char *)p->pkt[idx].iov_base + offset;
}
/**
* pool_flush() - Flush a packet pool
* @p: Pointer to packet pool
*/
void pool_flush(struct pool *p)
{
p->count = 0;
}
|