On Tue, Mar 15, 2016 at 09:28:07PM +0100, Carlos Falgueras García wrote:
> Now it is possible to store multiple variable length user data into rule.
> Modify the parser in order to fill the nftnl_udata with the comment, and
> the print function for extract these commentary and print it to user.
>
> Signed-off-by: Carlos Falgueras García <carlo...@riseup.net>
> ---
> include/rule.h | 7 +++++++
> src/netlink_delinearize.c | 52
> +++++++++++++++++++++++++++++++++++++++++++++--
> src/netlink_linearize.c | 16 +++++++++++++--
> 3 files changed, 71 insertions(+), 4 deletions(-)
>
> diff --git a/include/rule.h b/include/rule.h
> index c848f0f..b52f0ac 100644
> --- a/include/rule.h
> +++ b/include/rule.h
> @@ -4,6 +4,7 @@
> #include <stdint.h>
> #include <nftables.h>
> #include <list.h>
> +#include <libnftnl/udata.h>
>
> /**
> * struct handle - handle for tables, chains, rules and sets
> @@ -396,4 +397,10 @@ extern int do_command(struct netlink_ctx *ctx, struct
> cmd *cmd);
> extern int cache_update(enum cmd_ops cmd, struct list_head *msgs);
> extern void cache_release(void);
>
> +enum udata_type {
> + UDATA_TYPE_COMMENT,
> + __UDATA_TYPE_MAX,
> +};
> +#define UDATA_TYPE_MAX (__UDATA_TYPE_MAX - 1)
> +
> #endif /* NFTABLES_RULE_H */
> diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
> index d431588..5fcb5c1 100644
> --- a/src/netlink_delinearize.c
> +++ b/src/netlink_delinearize.c
> @@ -25,6 +25,7 @@
> #include <utils.h>
> #include <erec.h>
> #include <sys/socket.h>
> +#include <libnftnl/udata.h>
>
> struct netlink_parse_ctx {
> struct list_head *msgs;
> @@ -1746,6 +1747,54 @@ static void rule_parse_postprocess(struct
> netlink_parse_ctx *ctx, struct rule *r
> }
> }
>
> +static int parse_udata_cb(const struct nftnl_udata *attr, void *data)
> +{
> + unsigned char *value = nftnl_udata_attr_value(attr);
> + uint8_t type = nftnl_udata_attr_type(attr);
> + uint8_t len = nftnl_udata_attr_len(attr);
> + const struct nftnl_udata **tb = data;
> +
> + switch (type) {
> + case UDATA_TYPE_COMMENT:
> + if (value[len - 1] != '\0')
> + return -1;
> + break;
> + default:
> + break;
> + };
> +
> + tb[type] = attr;
> + return 1;
> +}
> +
> +static char *udata_get_comment(const void *data, uint32_t data_len)
> +{
> + const struct nftnl_udata *tb[UDATA_TYPE_MAX + 1] = {};
> + struct nftnl_udata_buf *udata;
> + uint8_t attr_len;
> + char *comment = NULL;
> +
> + udata = nftnl_udata_alloc(data_len);
> + if (!udata)
> + memory_allocation_error();
> + nftnl_udata_copy_data(udata, data, data_len);
> +
> + if (nftnl_udata_parse(udata, parse_udata_cb, tb) <= 0)
> + goto exit;
I think this should be instead:
if (nftnl_udata_parse(data, data_len, parse_udata_cb, tb) <= 0)
So you don't need to allocate the buffer then copy data into it.
I think the buffer infrastructure is only necessary to build the TLV
attributes, not to parse it.
> + if (!tb[UDATA_TYPE_COMMENT])
> + goto exit;
> +
> + attr_len = nftnl_udata_attr_len(tb[UDATA_TYPE_COMMENT]);
> + comment = xmalloc(attr_len);
> + memcpy(comment, nftnl_udata_attr_value(tb[UDATA_TYPE_COMMENT]),
> + attr_len);
I'd suggest:
comment = xstrdup(nftnl_udata_attr_get_str(tb[UDATA_TYPE_COMMENT]));
> +
> +exit:
> + nftnl_udata_free(udata);
> + return comment;
> +}
> +
> struct rule *netlink_delinearize_rule(struct netlink_ctx *ctx,
> const struct nftnl_rule *nlr)
> {
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