From: Laurent Vivier <lvivier(a)redhat.com>
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(a)redhat.com>
Reviewed-by: David Gibson <david(a)gibson.dropbear.id.au>
Message-ID: <20241010122903.1188992-2-lvivier(a)redhat.com>
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
packet.c | 80 ++++++++++++++++++++++++++++++--------------------------
packet.h | 14 ++--------
2 files changed, 45 insertions(+), 49 deletions(-)
diff --git a/packet.c b/packet.c
index ccfc846..3748996 100644
--- a/packet.c
+++ b/packet.c
@@ -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);
+ trace("data length %zu, offset %zu from length %zu, "
+ "%s:%i", len, offset, p->pkt[idx].iov_len,
+ 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,
- func, line);
- }
+ if (packet_check_range(p, offset, len, p->pkt[idx].iov_base,
+ func, line))
return NULL;
- }
if (left)
- *left = p->pkt[idx].len - offset - len;
+ *left = p->pkt[idx].iov_len - offset - len;
- return p->buf + p->pkt[idx].offset + offset;
+ return (char *)p->pkt[idx].iov_base + offset;
}
/**
diff --git a/packet.h b/packet.h
index a784b07..8377dcf 100644
--- a/packet.h
+++ b/packet.h
@@ -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) \
--
2.47.0