Hi Carlos,
Almost there, just a bit more small incremental changes.
On Thu, Mar 10, 2016 at 10:37:13PM +0100, Carlos Falgueras García wrote:
> These functions allow to create a buffer (nftnl_udata_buf) of TLV objects
> (nftnl_udata). It is inspired by libmnl/src/attr.c. It can be used to store
> several variable length user data into an object.
>
> Example usage:
> ```
> struct nftnl_udata_buf *buf;
> struct nftnl_udata *attr;
> const char str[] = "Hello World!";
>
> buf = nftnl_udata_alloc(UDATA_SIZE);
> if (!buf) {
> perror("OOM");
> exit(EXIT_FAILURE);
> }
>
> if (!nftnl_udata_put_strz(buf, MY_TYPE, str)) {
> perror("Can't put attribute \"%s\"", str);
> exit(EXIT_FAILURE);
> }
>
> nftnl_udata_for_each(buf, attr) {
> printf("%s\n", (char *)nftnl_udata_attr_value(attr));
> }
>
> nftnl_udata_free(buf);
> ```
>
> Signed-off-by: Carlos Falgueras García <carlosfg@xxxxxxxxxx>
> ---
> include/Makefile.am | 1 +
> include/libnftnl/Makefile.am | 1 +
> include/libnftnl/udata.h | 48 ++++++++++++++++
> include/udata.h | 40 +++++++++++++
> src/Makefile.am | 1 +
> src/libnftnl.map | 16 ++++++
> src/udata.c | 134 +++++++++++++++++++++++++++++++++++++++++++
> 7 files changed, 241 insertions(+)
> create mode 100644 include/libnftnl/udata.h
> create mode 100644 include/udata.h
> create mode 100644 src/udata.c
>
> diff --git a/include/Makefile.am b/include/Makefile.am
> index be9eb9b..9f55737 100644
> --- a/include/Makefile.am
> +++ b/include/Makefile.am
> @@ -12,4 +12,5 @@ noinst_HEADERS = internal.h \
> expr.h \
> json.h \
> set_elem.h \
> + udata.h \
> utils.h
> diff --git a/include/libnftnl/Makefile.am b/include/libnftnl/Makefile.am
> index 84f01b6..457ec95 100644
> --- a/include/libnftnl/Makefile.am
> +++ b/include/libnftnl/Makefile.am
> @@ -7,4 +7,5 @@ pkginclude_HEADERS = batch.h \
> set.h \
> ruleset.h \
> common.h \
> + udata.h \
> gen.h
> diff --git a/include/libnftnl/udata.h b/include/libnftnl/udata.h
> new file mode 100644
> index 0000000..a74e54c
> --- /dev/null
> +++ b/include/libnftnl/udata.h
> @@ -0,0 +1,48 @@
> +#ifndef _LIBNFTNL_UDATA_H_
> +#define _LIBNFTNL_UDATA_H_
> +
> +#include <stdio.h>
> +#include <stdint.h>
> +
> +/*
> + * nftnl user data attributes API
> + */
> +struct nftnl_udata;
> +struct nftnl_udata_buf;
> +
> +/* nftnl_udata_buf */
> +struct nftnl_udata_buf *nftnl_udata_alloc(size_t data_size);
> +void nftnl_udata_free(struct nftnl_udata_buf *buf);
> +size_t nftnl_udata_len(const struct nftnl_udata_buf *buf);
> +size_t nftnl_udata_size(const struct nftnl_udata_buf *buf);
> +void *nftnl_udata_data(const struct nftnl_udata_buf *buf);
> +void nftnl_udata_copy_data(struct nftnl_udata_buf *buf, const void *data,
> + size_t len);
> +struct nftnl_udata *nftnl_udata_start(const struct nftnl_udata_buf *buf);
> +struct nftnl_udata *nftnl_udata_end(const struct nftnl_udata_buf *buf);
> +
> +/* putters */
> +struct nftnl_udata *nftnl_udata_put(struct nftnl_udata_buf *buf, uint8_t type,
> + size_t len, const void *value);
> +struct nftnl_udata *nftnl_udata_put_strz(struct nftnl_udata_buf *buf,
> + uint8_t type, const char *strz);
> +
> +/* nftnl_udata_attr */
> +uint8_t nftnl_udata_attr_type(const struct nftnl_udata *attr);
> +uint8_t nftnl_udata_attr_len(const struct nftnl_udata *attr);
> +void *nftnl_udata_attr_value(const struct nftnl_udata *attr);
> +
> +/* iterator */
> +struct nftnl_udata *nftnl_udata_attr_next(const struct nftnl_udata *attr);
> +
> +#define nftnl_udata_for_each(buf, attr) \
> + for ((attr) = nftnl_udata_start(buf); \
> + (char *)(nftnl_udata_end(buf)) > (char *)(attr); \
> + (attr) = nftnl_udata_attr_next(attr))
> +
> +typedef int (*nftnl_udata_cb_t)(const struct nftnl_udata *attr,
> + void *data);
> +int nftnl_udata_parse(const struct nftnl_udata_buf *buf, nftnl_udata_cb_t cb,
> + void *data);
> +
> +#endif /* _LIBNFTNL_UDATA_H_ */
> diff --git a/include/udata.h b/include/udata.h
> new file mode 100644
> index 0000000..271ee50
> --- /dev/null
> +++ b/include/udata.h
> @@ -0,0 +1,40 @@
> +#ifndef _LIBNFTNL_UDATA_INTERNAL_H_
> +#define _LIBNFTNL_UDATA_INTERNAL_H_
> +
> +#include <stdint.h>
> +#include <stddef.h>
> +
> +/*
> + * TLV structures:
> + * nftnl_udata
> + * <-------- HEADER --------> <------ PAYLOAD ------>
> + * +------------+-------------+- - - - - - - - - - - -+
> + * | type | len | value |
> + * | (1 byte) | (1 byte) | |
> + * +--------------------------+- - - - - - - - - - - -+
> + * <-- sizeof(nftnl_udata) -> <-- nftnl_udata->len -->
> + */
> +struct nftnl_udata {
> + uint8_t type;
> + uint8_t len;
> + unsigned char value[];
> +} __attribute__((__packed__));
> +
> +/*
> + * +---------------------------------++
> + * | data[] ||
> + * | || ||
> + * | \/ \/
> + * +-------+-------+-------+-------+ ... +-------+- - - - - - -+
> + * | size | end | TLV | TLV | | TLV | Empty |
> + * +-------+-------+-------+-------+ ... +-------+- - - - - - -+
> + * |<---- nftnl_udata_len() ---->|
> + * |<----------- nftnl_udata_size() ---------->|
> + */
> +struct nftnl_udata_buf {
> + size_t size;
> + char *end;
> + char data[];
> +};
> +
> +#endif /* _LIBNFTNL_UDATA_INTERNAL_H_ */
> diff --git a/src/Makefile.am b/src/Makefile.am
> index a27e292..7e580e4 100644
> --- a/src/Makefile.am
> +++ b/src/Makefile.am
> @@ -19,6 +19,7 @@ libnftnl_la_SOURCES = utils.c \
> ruleset.c \
> mxml.c \
> jansson.c \
> + udata.c \
> expr.c \
> expr_ops.c \
> expr/bitwise.c \
> diff --git a/src/libnftnl.map b/src/libnftnl.map
> index 2e193b7..d6cd2a7 100644
> --- a/src/libnftnl.map
> +++ b/src/libnftnl.map
> @@ -336,6 +336,22 @@ global:
> nftnl_set_snprintf;
> nftnl_set_fprintf;
>
> + nftnl_udata_alloc;
> + nftnl_udata_free;
> + nftnl_udata_len;
> + nftnl_udata_size;
> + nftnl_udata_data;
> + nftnl_udata_copy_data;
> + nftnl_udata_start;
> + nftnl_udata_end;
> + nftnl_udata_put;
> + nftnl_udata_put_strz;
> + nftnl_udata_attr_type;
> + nftnl_udata_attr_len;
> + nftnl_udata_attr_value;
> + nftnl_udata_attr_next;
> + nftnl_udata_parse;
Please, add these new symbols to LIBNFTNL_4.1.
> nftnl_set_list_alloc;
> nftnl_set_list_free;
> nftnl_set_list_add;
> diff --git a/src/udata.c b/src/udata.c
> new file mode 100644
> index 0000000..0503ca3
> --- /dev/null
> +++ b/src/udata.c
> @@ -0,0 +1,134 @@
> +#include <libnftnl/udata.h>
> +#include <udata.h>
> +#include <utils.h>
> +
> +#include <stdlib.h>
> +#include <stdint.h>
> +#include <string.h>
> +
> +struct nftnl_udata_buf *nftnl_udata_alloc(size_t data_size)
> +{
> + struct nftnl_udata_buf *buf;
> +
> + buf = (struct nftnl_udata_buf *)
> + malloc(sizeof(struct nftnl_udata_buf) + data_size);
No need for casting, ie.
buf = malloc(sizeof(struct nftnl_udata_buf) + data_size);
> + if (!buf)
> + return NULL;
> + buf->size = data_size;
> + buf->end = buf->data;
> +
> + return buf;
> +}
> +EXPORT_SYMBOL(nftnl_udata_alloc);
> +
> +void nftnl_udata_free(struct nftnl_udata_buf *buf)
> +{
> + buf->size = 0;
> + buf->end = NULL;
> + free((void *)buf);
^^^^^^^^
No need for cast this either here.
> +}
> +EXPORT_SYMBOL(nftnl_udata_free);
> +
> +size_t nftnl_udata_len(const struct nftnl_udata_buf *buf)
Better use uint32_t instead of size_t. This type depends on the arch
so in 32 bit will be u32 and in 64 bit will be u64.
And uint32_t should be sufficient for this, same thing here and
everywhere else.
> +{
> + return (size_t)(buf->end - buf->data);
> +}
> +EXPORT_SYMBOL(nftnl_udata_len);
> +
> +size_t nftnl_udata_size(const struct nftnl_udata_buf *buf)
Same thing here.
> +{
> + return buf->size;
> +}
> +EXPORT_SYMBOL(nftnl_udata_size);
> +
> +void *nftnl_udata_data(const struct nftnl_udata_buf *buf)
> +{
> + return (void *)buf->data;
> +}
> +EXPORT_SYMBOL(nftnl_udata_data);
> +
> +void nftnl_udata_copy_data(struct nftnl_udata_buf *buf,
> + const void *data, size_t len)
> +{
> + memcpy(buf->data, data, len <= buf->size ? len : buf->size);
> + buf->end = buf->data + len;
> +}
> +EXPORT_SYMBOL(nftnl_udata_copy_data);
> +
> +struct nftnl_udata *nftnl_udata_start(const struct nftnl_udata_buf *buf)
> +{
> + return (struct nftnl_udata *)buf->data;
> +}
> +EXPORT_SYMBOL(nftnl_udata_start);
> +
> +struct nftnl_udata *nftnl_udata_end(const struct nftnl_udata_buf *buf)
> +{
> + return (struct nftnl_udata *)buf->end;
> +}
> +EXPORT_SYMBOL(nftnl_udata_end);
> +
> +struct nftnl_udata *nftnl_udata_put(struct nftnl_udata_buf *buf,
> + uint8_t type, size_t len, const void *value)
> +{
> + struct nftnl_udata *attr = NULL;
> +
> + /* Check if there is enough space */
Remove this comment.
> + if (buf->size >= len + sizeof(struct nftnl_udata)) {
> + attr = (struct nftnl_udata *)buf->end;
> + attr->len = len;
> + attr->type = type;
> + memcpy(attr->value, value, len);
> +
> + buf->end = (char *)nftnl_udata_attr_next(attr);
> + }
> +
> + return attr;
Why return the nftnl_udata? You can just return a boolean instead.
Same thing in nftnl_udata_put_strz().
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