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packet: replace struct desc by struct iovec

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To be able to manage buffers inside a shared memory provided
by a VM via a vhost-user interface, we cannot rely on the fact
that buffers are located in a pre-defined memory area and use
a base address and a 32bit offset to address them.

We need a 64bit address, so replace struct desc by struct iovec
and update range checking.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Laurent Vivier 2024-11-22 17:43:28 +01:00 committed by Stefano Brivio
parent c0fbc7ef2a
commit dd143e3890
2 changed files with 47 additions and 51 deletions
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84
packet.c
View File

@ -22,6 +22,35 @@
#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
@ -41,34 +70,16 @@ void packet_add_do(struct pool *p, size_t len, const char *start,
return;
}
if (start < p->buf) {
trace("add packet start %p before buffer start %p, %s:%i",
(void *)start, (void *)p->buf, func, line);
if (packet_check_range(p, 0, len, start, func, line))
return;
}
if (start + len > p->buf + p->buf_size) {
trace("add packet start %p, length: %zu, buffer end %p, %s:%i",
(void *)start, len, (void *)(p->buf + p->buf_size),
func, line);
return;
}
if (len > UINT16_MAX) {
trace("add packet length %zu, %s:%i", len, func, line);
return;
}
#if UINTPTR_MAX == UINT64_MAX
if ((uintptr_t)start - (uintptr_t)p->buf > UINT32_MAX) {
trace("add packet start %p, buffer start %p, %s:%i",
(void *)start, (void *)p->buf, func, line);
return;
}
#endif
p->pkt[idx].offset = start - p->buf;
p->pkt[idx].len = len;
p->pkt[idx].iov_base = (void *)start;
p->pkt[idx].iov_len = len;
p->count++;
}
@ -96,36 +107,31 @@ void *packet_get_do(const struct pool *p, size_t idx, size_t offset,
return NULL;
}
if (len > UINT16_MAX || len + offset > UINT32_MAX) {
if (len > UINT16_MAX) {
if (func) {
trace("packet data length %zu, offset %zu, %s:%i",
len, offset, func, line);
trace("packet data length %zu, %s:%i",
len, func, line);
}
return NULL;
}
if (p->pkt[idx].offset + len + offset > p->buf_size) {
if (len + offset > p->pkt[idx].iov_len) {
if (func) {
trace("packet offset plus length %zu from size %zu, "
"%s:%i", p->pkt[idx].offset + len + offset,
p->buf_size, func, line);
}
return NULL;
}
if (len + offset > p->pkt[idx].len) {
if (func) {
trace("data length %zu, offset %zu from length %u, "
"%s:%i", len, offset, p->pkt[idx].len,
trace("data length %zu, offset %zu from length %zu, "
"%s:%i", len, offset, p->pkt[idx].iov_len,
func, line);
}
return NULL;
}
if (left)
*left = p->pkt[idx].len - offset - len;
if (packet_check_range(p, offset, len, p->pkt[idx].iov_base,
func, line))
return NULL;
return p->buf + p->pkt[idx].offset + offset;
if (left)
*left = p->pkt[idx].iov_len - offset - len;
return (char *)p->pkt[idx].iov_base + offset;
}
/**

14
packet.h
View File

@ -6,16 +6,6 @@
#ifndef PACKET_H
#define PACKET_H
/**
* struct desc - Generic offset-based descriptor within buffer
* @offset: Offset of descriptor relative to buffer start, 32-bit limit
* @len: Length of descriptor, host order, 16-bit limit
*/
struct desc {
uint32_t offset;
uint16_t len;
};
/**
* struct pool - Generic pool of packets stored in a buffer
* @buf: Buffer storing packet descriptors
@ -29,7 +19,7 @@ struct pool {
size_t buf_size;
size_t size;
size_t count;
struct desc pkt[1];
struct iovec pkt[1];
};
void packet_add_do(struct pool *p, size_t len, const char *start,
@ -54,7 +44,7 @@ struct _name ## _t { \
size_t buf_size; \
size_t size; \
size_t count; \
struct desc pkt[_size]; \
struct iovec pkt[_size]; \
}
#define PACKET_POOL_INIT_NOCAST(_size, _buf, _buf_size) \