5b6c68c2e4
A classic gotcha of the standard C library is that its unwise to call any variable 'index' because it will shadow the standard string library function index(3). This can cause warnings from cppcheck amongst others, and it also means that if the variable is removed you tend to get confusing type errors (or sometimes nothing at all) instead of a nice simple "name is not defined" error. Strictly speaking this only occurs if <string.h> is included, but that is so common that as a rule it's best to just avoid it always. We have a number of places which hit this trap, so rename variables and parameters to avoid it. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
137 lines
3.4 KiB
C
137 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* PASST - Plug A Simple Socket Transport
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* for qemu/UNIX domain socket mode
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*
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* PASTA - Pack A Subtle Tap Abstraction
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* for network namespace/tap device mode
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*
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* packet.c - Packet abstraction: add packets to pool, flush, get packet data
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*
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* Copyright (c) 2020-2021 Red Hat GmbH
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* Author: Stefano Brivio <sbrivio@redhat.com>
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*/
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#include <limits.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <netinet/ip6.h>
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#include "packet.h"
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#include "util.h"
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#include "log.h"
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/**
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* packet_add_do() - Add data as packet descriptor to given pool
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* @p: Existing pool
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* @len: Length of new descriptor
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* @start: Start of data
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* @func: For tracing: name of calling function, NULL means no trace()
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* @line: For tracing: caller line of function call
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*/
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void packet_add_do(struct pool *p, size_t len, const char *start,
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const char *func, int line)
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{
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size_t idx = p->count;
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if (idx >= p->size) {
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trace("add packet index %lu to pool with size %lu, %s:%i",
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idx, p->size, func, line);
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return;
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}
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if (start < p->buf) {
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trace("add packet start %p before buffer start %p, %s:%i",
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start, p->buf, func, line);
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return;
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}
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if (start + len > p->buf + p->buf_size) {
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trace("add packet start %p, length: %lu, buffer end %p, %s:%i",
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start, len, p->buf + p->buf_size, func, line);
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return;
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}
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if (len > UINT16_MAX) {
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trace("add packet length %lu, %s:%i", len, func, line);
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return;
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}
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#if UINTPTR_MAX == UINT64_MAX
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if ((uintptr_t)start - (uintptr_t)p->buf > UINT32_MAX) {
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trace("add packet start %p, buffer start %p, %s:%i",
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start, p->buf, func, line);
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return;
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}
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#endif
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p->pkt[idx].offset = start - p->buf;
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p->pkt[idx].len = len;
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p->count++;
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}
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/**
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* packet_get_do() - Get data range from packet descriptor from given pool
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* @p: Packet pool
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* @idx: Index of packet descriptor in pool
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* @offset: Offset of data range in packet descriptor
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* @len: Length of desired data range
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* @left: Length of available data after range, set on return, can be NULL
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* @func: For tracing: name of calling function, NULL means no trace()
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* @line: For tracing: caller line of function call
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*
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* Return: pointer to start of data range, NULL on invalid range or descriptor
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*/
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void *packet_get_do(const struct pool *p, size_t idx, size_t offset,
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size_t len, size_t *left, const char *func, int line)
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{
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if (idx >= p->size || idx >= p->count) {
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if (func) {
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trace("packet %lu from pool size: %lu, count: %lu, "
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"%s:%i", idx, p->size, p->count, func, line);
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}
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return NULL;
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}
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if (len > UINT16_MAX || len + offset > UINT32_MAX) {
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if (func) {
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trace("packet data length %lu, offset %lu, %s:%i",
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len, offset, func, line);
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}
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return NULL;
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}
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if (p->pkt[idx].offset + len + offset > p->buf_size) {
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if (func) {
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trace("packet offset plus length %lu from size %lu, "
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"%s:%i", p->pkt[idx].offset + len + offset,
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p->buf_size, func, line);
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}
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return NULL;
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}
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if (len + offset > p->pkt[idx].len) {
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if (func) {
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trace("data length %lu, offset %lu from length %u, "
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"%s:%i", len, offset, p->pkt[idx].len,
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func, line);
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}
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return NULL;
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}
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if (left)
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*left = p->pkt[idx].len - offset - len;
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return p->buf + p->pkt[idx].offset + offset;
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}
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/**
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* pool_flush() - Flush a packet pool
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* @p: Pointer to packet pool
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*/
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void pool_flush(struct pool *p)
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{
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p->count = 0;
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}
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