On Fri, Jul 12, 2024 at 05:32:41PM +0200, Laurent Vivier wrote: > 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 > --- > packet.c | 84 +++++++++++++++++++++++++++++++------------------------- > packet.h | 14 ++-------- > 2 files changed, 49 insertions(+), 49 deletions(-) > > diff --git a/packet.c b/packet.c > index ccfc84607709..f7bb523c4ffa 100644 > --- a/packet.c > +++ b/packet.c > @@ -22,6 +22,39 @@ > #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, NULL means no trace() > + * @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) { > + if (func) { Omitting the message entirely if func is not set doesn't seem correct. I believe printf() should format NULL pointers sanely (typically as ""), so I think you can just leave out this check. > + trace("add 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) { It's not really clear to me why offset is needed in here. AIUI, offset is used when we want to talk about some piece of a larger packet/frame that's in the buffer. That's useful when we're dissecting packets, but surely we always want the whole frame/whatever to be within the buffer, so I don't know we need the extra complexity in this helper. I also think we should check for overflow on the LHS here, but that's pre-existing, so it doesn't need to go in this patch. > + if (func) { > + 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 +74,16 @@ 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 +111,31 @@ 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); Should this be an assert? Seems like something is wrong in the caller, if they're trying to pass in a ludicrously long packet. > } > 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 a784b07bbed5..8377dcf678bb 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) \ -- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson