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All errors from packet_range_check(), packet_add() and packet_get() are trace level. However, these are for the most part actual error conditions. They're states that should not happen, in many cases indicating a bug in the caller or elswhere. We don't promote these to err() or ASSERT() level, for fear of a localised bug on very specific input crashing the entire program, or flooding the logs, but we can at least upgrade them to debug level. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
191 lines
4.8 KiB
C
191 lines
4.8 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_check_range() - Check if a memory range is valid for a pool
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* @p: Packet pool
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* @ptr: Start of desired data range
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* @len: Length of desired data range
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* @func: For tracing: name of calling function
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* @line: For tracing: caller line of function call
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*
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* Return: 0 if the range is valid, -1 otherwise
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*/
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static int packet_check_range(const struct pool *p, const char *ptr, size_t len,
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const char *func, int line)
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{
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if (len > PACKET_MAX_LEN) {
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debug("packet range length %zu (max %zu), %s:%i",
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len, PACKET_MAX_LEN, func, line);
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return -1;
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}
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if (p->buf_size == 0) {
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int ret;
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ret = vu_packet_check_range((void *)p->buf, ptr, len);
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if (ret == -1)
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debug("cannot find region, %s:%i", func, line);
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return ret;
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}
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if (ptr < p->buf) {
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debug("packet range start %p before buffer start %p, %s:%i",
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(void *)ptr, (void *)p->buf, func, line);
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return -1;
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}
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if (len > p->buf_size) {
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debug("packet range length %zu larger than buffer %zu, %s:%i",
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len, p->buf_size, func, line);
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return -1;
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}
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if ((size_t)(ptr - p->buf) > p->buf_size - len) {
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debug("packet range %p, len %zu after buffer end %p, %s:%i",
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(void *)ptr, len, (void *)(p->buf + p->buf_size),
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func, line);
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return -1;
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}
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return 0;
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}
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/**
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* pool_full() - Is a packet pool full?
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* @p: Pointer to packet pool
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*
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* Return: true if the pool is full, false if more packets can be added
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*/
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bool pool_full(const struct pool *p)
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{
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return p->count >= p->size;
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}
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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
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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 (pool_full(p)) {
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debug("add packet index %zu to pool with size %zu, %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 (packet_check_range(p, start, len, func, line))
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return;
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p->pkt[idx].iov_base = (void *)start;
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p->pkt[idx].iov_len = len;
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p->count++;
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}
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/**
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* packet_get_try_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
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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_try_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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char *ptr;
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ASSERT_WITH_MSG(p->count <= p->size,
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"Corrupt pool count: %zu, size: %zu, %s:%i",
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p->count, p->size, func, line);
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if (idx >= p->count) {
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debug("packet %zu from pool count: %zu, %s:%i",
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idx, p->count, func, line);
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return NULL;
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}
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if (offset > p->pkt[idx].iov_len ||
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len > (p->pkt[idx].iov_len - offset))
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return NULL;
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ptr = (char *)p->pkt[idx].iov_base + offset;
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ASSERT_WITH_MSG(!packet_check_range(p, ptr, len, func, line),
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"Corrupt packet pool, %s:%i", func, line);
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if (left)
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*left = p->pkt[idx].iov_len - offset - len;
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return ptr;
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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
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* @line: For tracing: caller line of function call
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*
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* Return: as packet_get_try_do() but log a trace message when returning NULL
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*/
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void *packet_get_do(const struct pool *p, const size_t idx,
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size_t offset, size_t len, size_t *left,
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const char *func, int line)
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{
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void *r = packet_get_try_do(p, idx, offset, len, left, func, line);
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if (!r) {
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trace("missing packet data length %zu, offset %zu from "
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"length %zu, %s:%i",
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len, offset, p->pkt[idx].iov_len, func, line);
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}
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return r;
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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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