On 1/17/18 2:48 AM, Jiri Pirko wrote:
> From: Jiri Pirko <[email protected]>
>
> This hepler used qdisc dump to list all qdisc and find if block index in
> question is used by any of them. That means the block with specified
> index exists.
>
> Signed-off-by: Jiri Pirko <[email protected]>
> ---
> tc/tc_qdisc.c | 61
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> tc/tc_util.h | 2 ++
> 2 files changed, 63 insertions(+)
>
> diff --git a/tc/tc_qdisc.c b/tc/tc_qdisc.c
> index 70279b9..3f91558 100644
> --- a/tc/tc_qdisc.c
> +++ b/tc/tc_qdisc.c
> @@ -412,3 +412,64 @@ int do_qdisc(int argc, char **argv)
> fprintf(stderr, "Command \"%s\" is unknown, try \"tc qdisc help\".\n",
> *argv);
> return -1;
> }
> +
> +struct tc_qdisc_block_exists_ctx {
> + __u32 block_index;
> + bool found;
> +};
> +
> +static int tc_qdisc_block_exists_cb(const struct sockaddr_nl *who,
> + struct nlmsghdr *n, void *arg)
> +{
> + struct tc_qdisc_block_exists_ctx *ctx = arg;
> + struct tcmsg *t = NLMSG_DATA(n);
> + int len = n->nlmsg_len;
> + struct rtattr *tb[TCA_MAX+1];
reverse xmas tree
> +
> + if (n->nlmsg_type != RTM_NEWQDISC)
> + return 0;
> +
> + len -= NLMSG_LENGTH(sizeof(*t));
> + if (len < 0)
> + return -1;
> +
> + parse_rtattr(tb, TCA_MAX, TCA_RTA(t), len);
> +
> + if (tb[TCA_KIND] == NULL)
> + return -1;
> +
> + if (tb[TCA_INGRESS_BLOCK] &&
> + RTA_PAYLOAD(tb[TCA_INGRESS_BLOCK]) >= sizeof(__u32)) {
why not just == sizeof(__u32) since that's what it should be?
> + __u32 block = rta_getattr_u32(tb[TCA_INGRESS_BLOCK]);
> +
> + if (block && block == ctx->block_index)
block > 0 test should not be needed. If someone is calling
tc_qdisc_block_exists, then block_index should be > 0 in which case you
just need block == ctx->block_index
> + ctx->found = true;
> + }
> +
> + if (tb[TCA_EGRESS_BLOCK] &&
> + RTA_PAYLOAD(tb[TCA_EGRESS_BLOCK]) >= sizeof(__u32)) {
> + __u32 block = rta_getattr_u32(tb[TCA_EGRESS_BLOCK]);
> +
> + if (block && block == ctx->block_index)
same 2 comments for this block
> + ctx->found = true;
> + }
> + return 0;
> +}
> +
> +int tc_qdisc_block_exists(__u32 block_index)
This should be bool since you are returning true / false
> +{
> + struct tc_qdisc_block_exists_ctx ctx = { .block_index = block_index };
> + struct tcmsg t = { .tcm_family = AF_UNSPEC };
> +
> + if (rtnl_dump_request(&rth, RTM_GETQDISC, &t, sizeof(t)) < 0) {
> + perror("Cannot send dump request");
> + return false;
> + }
> +
> + if (rtnl_dump_filter(&rth, tc_qdisc_block_exists_cb, &ctx) < 0) {
> + perror("Dump terminated\n");
> + return false;
> + }
> +
> + return ctx.found;
> +}
> diff --git a/tc/tc_util.h b/tc/tc_util.h
> index 1218610..72f4282 100644
> --- a/tc/tc_util.h
> +++ b/tc/tc_util.h
> @@ -132,4 +132,6 @@ int prio_print_opt(struct qdisc_util *qu, FILE *f, struct
> rtattr *opt);
> int cls_names_init(char *path);
> void cls_names_uninit(void);
>
> +int tc_qdisc_block_exists(__u32 block_index);
> +
> #endif
>
