On Tue, Mar 15, 2016 at 09:28:04PM +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));
> }
>
u> 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 | 49 ++++++++++++++++
> include/udata.h | 40 +++++++++++++
> src/Makefile.am | 1 +
> src/libnftnl.map | 32 +++++++++++
> src/udata.c | 133 +++++++++++++++++++++++++++++++++++++++++++
> 7 files changed, 257 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..f65a1dc
> --- /dev/null
> +++ b/include/libnftnl/udata.h
> @@ -0,0 +1,49 @@
> +#ifndef _LIBNFTNL_UDATA_H_
> +#define _LIBNFTNL_UDATA_H_
> +
> +#include <stdio.h>
> +#include <stdint.h>
> +#include <stdbool.h>
> +
> +/*
> + * nftnl user data attributes API
> + */
> +struct nftnl_udata;
> +struct nftnl_udata_buf;
> +
> +/* nftnl_udata_buf */
> +struct nftnl_udata_buf *nftnl_udata_alloc(uint32_t data_size);
> +void nftnl_udata_free(struct nftnl_udata_buf *buf);
If nftnl_udata_alloc() returns struct nftnl_udata_buf, then it's
better to call this:
nftnl_udata_buf_alloc()
instead.
> +uint32_t nftnl_udata_len(const struct nftnl_udata_buf *buf);
> +uint32_t nftnl_udata_size(const struct nftnl_udata_buf *buf);
> +void *nftnl_udata_data(const struct nftnl_udata_buf *buf);
Same thing for these functions: nftnl_udata_buf_*().
> +void nftnl_udata_copy_data(struct nftnl_udata_buf *buf, const void *data,
> + uint32_t len);
Please, rename this to:
nftnl_udata_buf_put()
> +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 */
> +bool nftnl_udata_put(struct nftnl_udata_buf *buf, uint8_t type, uint32_t len,
> + const void *value);
> +bool 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..407a3b9
> --- /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 {
> + uint32_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..329caca 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;
These above, you can remove them...
> nftnl_set_list_alloc;
> nftnl_set_list_free;
> nftnl_set_list_add;
> @@ -512,4 +528,20 @@ LIBNFTNL_4.1 {
> nftnl_trace_get_data;
>
> nftnl_trace_nlmsg_parse;
> +
> + 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;
... Since now you have placed them here in the right place, which is
the list of new symbols available under LIBNFTNL_4.1 :)
> } LIBNFTNL_4;
> diff --git a/src/udata.c b/src/udata.c
> new file mode 100644
> index 0000000..61ee6c9
> --- /dev/null
> +++ b/src/udata.c
> @@ -0,0 +1,133 @@
> +#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(uint32_t data_size)
> +{
> + struct nftnl_udata_buf *buf;
> +
> + 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;
No need to set this to zero and NULL given that we're just releasing
this object.
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
