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pping: Check if creating clsact on ingress

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The userspace loader would only check if the tc clsact was created
when the egress program was loaded. Thus, if the ingress program
created the clsact the egress program would not have to create the
clsact, the ePPing would thus falsely believe it did not create a
clsact and fail to remove it on shutdown even if --force was used. Fix
this by checking if either ingress or egress created clsact.

This bug was introduced as a sneaky side effect of commit
78b45bde56 (pping: Use libxdp to load
and attach XDP program). Before this commit the egress program (for
which there is only a tc alternative) would be loaded first, and thus
it was sufficient to check if it created the clsact. When switching to
libxdp however, the ingress program (specifically the XDP program) had
to be loaded first, and thus the order of loading ingress and egress
program were swapped. Therefore, it was no longer sufficient to only
check the egress program as the tc ingress program may have created
the clsact before the the egress program is attached (and only
checking the ingress program would also not be enough as the tc
ingress program may never be loaded if XDP mode is used instead).

Signed-off-by: Simon Sundberg <simon.sundberg@kau.se>
This commit is contained in:
Simon Sundberg
2022-09-01 17:21:42 +02:00
parent af5db036ab
commit ddf25abfcc
1 changed files with 7 additions and 7 deletions
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14
pping/pping.c
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@@ -864,6 +864,7 @@ static int load_attach_bpfprogs(struct bpf_object **obj,
struct pping_config *config)
{
int err, detach_err;
config->created_tc_hook = false;
// Open and load ELF file
*obj = bpf_object__open(config->object_path);
@@ -897,8 +898,8 @@ static int load_attach_bpfprogs(struct bpf_object **obj,
return err;
}
err = tc_attach(*obj, config->ifindex, BPF_TC_INGRESS,
config->ingress_prog,
&config->tc_ingress_opts, NULL);
config->ingress_prog, &config->tc_ingress_opts,
&config->created_tc_hook);
config->ingress_prog_id = err;
}
if (err < 0) {
@@ -909,10 +910,10 @@ static int load_attach_bpfprogs(struct bpf_object **obj,
}
// Attach egress prog
config->egress_prog_id =
tc_attach(*obj, config->ifindex, BPF_TC_EGRESS,
config->egress_prog, &config->tc_egress_opts,
&config->created_tc_hook);
config->egress_prog_id = tc_attach(
*obj, config->ifindex, BPF_TC_EGRESS, config->egress_prog,
&config->tc_egress_opts,
config->created_tc_hook ? NULL : &config->created_tc_hook);
if (config->egress_prog_id < 0) {
fprintf(stderr,
"Failed attaching egress BPF program on interface %s: %s\n",
@@ -922,7 +923,6 @@ static int load_attach_bpfprogs(struct bpf_object **obj,
goto egress_err;
}
return 0;
egress_err: