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// SPDX-License-Identifier: AGPL-3.0-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"
/**
* 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 index = p->count;
if (index >= p->size) {
trace("add packet index %lu to pool with size %lu, %s:%i",
index, p->size, func, line);
return;
}
if (start < p->buf) {
trace("add packet start %p before buffer start %p, %s:%i",
start, 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",
start, len, p->buf + p->buf_size, func, line);
return;
}
if (len > UINT16_MAX) {
trace("add packet length %lu, %s:%i", len, func, line);
return;
}
if ((unsigned int)((intptr_t)start - (intptr_t)p->buf) > UINT32_MAX) {
trace("add packet start %p, buffer start %p, %s:%i",
start, p->buf, func, line);
return;
}
p->pkt[index].offset = start - p->buf;
p->pkt[index].len = len;
p->count++;
}
/**
* packet_get_do() - Get data range from packet descriptor from given pool
* @p: Packet pool
* @index: 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 index, size_t offset,
size_t len, size_t *left, const char *func, int line)
{
if (index > p->size || index > p->count) {
if (func) {
trace("packet %lu from pool size: %lu, count: %lu, "
"%s:%i", index, 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[index].offset + len + offset > p->buf_size) {
if (func) {
trace("packet offset plus length %lu from size %lu, "
"%s:%i", p->pkt[index].offset + len + offset,
p->buf_size, func, line);
}
return NULL;
}
if (len + offset > p->pkt[index].len) {
if (func) {
trace("data length %lu, offset %lu from length %u, "
"%s:%i", len, offset, p->pkt[index].len,
func, line);
}
return NULL;
}
if (left)
*left = p->pkt[index].len - offset - len;
return p->buf + p->pkt[index].offset + offset;
}
/**
* pool_flush() - Flush a packet pool
* @p: Pointer to packet pool
*/
void pool_flush(struct pool *p)
{
p->count = 0;
}
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