2023-05-11 15:41:39

by Larysa Zaremba

[permalink] [raw]
Subject: [PATCH bpf-next] bpftool: specify XDP Hints ifname when loading program

Add ability to specify a network interface used to resolve
XDP Hints kfuncs when loading program through bpftool.

Usage:
bpftool prog load <bpf_obj_path> <pin_path> dev xdpmeta <ifname>

Signed-off-by: Larysa Zaremba <[email protected]>
---
tools/bpf/bpftool/prog.c | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 91b6075b2db3..a9cb96d99277 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1517,12 +1517,13 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
struct bpf_program *prog = NULL, *pos;
unsigned int old_map_fds = 0;
const char *pinmaps = NULL;
+ __u32 offload_ifindex = 0;
bool auto_attach = false;
+ __u32 meta_ifindex = 0;
struct bpf_object *obj;
struct bpf_map *map;
const char *pinfile;
unsigned int i, j;
- __u32 ifindex = 0;
const char *file;
int idx, err;

@@ -1614,17 +1615,25 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
map_replace[old_map_fds].fd = fd;
old_map_fds++;
} else if (is_prefix(*argv, "dev")) {
+ __u32 *cur_ifindex;
+
NEXT_ARG();

- if (ifindex) {
- p_err("offload device already specified");
+ if (offload_ifindex || meta_ifindex) {
+ p_err("device already specified");
goto err_free_reuse_maps;
}
+ if (is_prefix(*argv, "xdpmeta")) {
+ cur_ifindex = &meta_ifindex;
+ NEXT_ARG();
+ } else {
+ cur_ifindex = &offload_ifindex;
+ }
if (!REQ_ARGS(1))
goto err_free_reuse_maps;

- ifindex = if_nametoindex(*argv);
- if (!ifindex) {
+ *cur_ifindex = if_nametoindex(*argv);
+ if (!(*cur_ifindex)) {
p_err("unrecognized netdevice '%s': %s",
*argv, strerror(errno));
goto err_free_reuse_maps;
@@ -1671,7 +1680,12 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
goto err_close_obj;
}

- bpf_program__set_ifindex(pos, ifindex);
+ if (prog_type == BPF_PROG_TYPE_XDP && meta_ifindex) {
+ bpf_program__set_flags(pos, BPF_F_XDP_DEV_BOUND_ONLY);
+ bpf_program__set_ifindex(pos, meta_ifindex);
+ } else {
+ bpf_program__set_ifindex(pos, offload_ifindex);
+ }
if (bpf_program__type(pos) != prog_type)
bpf_program__set_type(pos, prog_type);
bpf_program__set_expected_attach_type(pos, expected_attach_type);
@@ -1709,7 +1723,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
idx = 0;
bpf_object__for_each_map(map, obj) {
if (bpf_map__type(map) != BPF_MAP_TYPE_PERF_EVENT_ARRAY)
- bpf_map__set_ifindex(map, ifindex);
+ bpf_map__set_ifindex(map, offload_ifindex);

if (j < old_map_fds && idx == map_replace[j].idx) {
err = bpf_map__reuse_fd(map, map_replace[j++].fd);
--
2.35.3



2023-05-12 10:26:49

by Quentin Monnet

[permalink] [raw]
Subject: Re: [PATCH bpf-next] bpftool: specify XDP Hints ifname when loading program

2023-05-11 17:13 UTC+0200 ~ Larysa Zaremba <[email protected]>
> Add ability to specify a network interface used to resolve
> XDP Hints kfuncs when loading program through bpftool.
>
> Usage:
> bpftool prog load <bpf_obj_path> <pin_path> dev xdpmeta <ifname>

Thanks for this patch!

Regarding the command-line syntax, I'm not a big fan of the optional
sub-keyword for the device for XDP hints. I must admit I had not
anticipated other another use for the "dev" keyword. Instead, have you
considered one of the following:

1) Adding a different keyword ("xdpmeta_dev"?) and making it
incompatible with "dev"

2) Another alternative would be adding a sub-keyword for offload too:

bpftool p l [...] dev <[offload <ifname> | xdpmeta <ifname>]>

If the ifname is provided with no sub-keyword, we would consider it for
offload for legacy support, possibly warn that the syntax is deprecated.

What do you think?

>
> Signed-off-by: Larysa Zaremba <[email protected]>
> ---
> tools/bpf/bpftool/prog.c | 28 +++++++++++++++++++++-------
> 1 file changed, 21 insertions(+), 7 deletions(-)
>
> diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
> index 91b6075b2db3..a9cb96d99277 100644
> --- a/tools/bpf/bpftool/prog.c
> +++ b/tools/bpf/bpftool/prog.c
> @@ -1517,12 +1517,13 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> struct bpf_program *prog = NULL, *pos;
> unsigned int old_map_fds = 0;
> const char *pinmaps = NULL;
> + __u32 offload_ifindex = 0;
> bool auto_attach = false;
> + __u32 meta_ifindex = 0;
> struct bpf_object *obj;
> struct bpf_map *map;
> const char *pinfile;
> unsigned int i, j;
> - __u32 ifindex = 0;
> const char *file;
> int idx, err;
>
> @@ -1614,17 +1615,25 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> map_replace[old_map_fds].fd = fd;
> old_map_fds++;
> } else if (is_prefix(*argv, "dev")) {
> + __u32 *cur_ifindex;
> +
> NEXT_ARG();
>
> - if (ifindex) {
> - p_err("offload device already specified");
> + if (offload_ifindex || meta_ifindex) {
> + p_err("device already specified");

I'd add a note to tell somehow that offload and XDP hints are mutually
exclusive. I suspect not all users understand these well.

> goto err_free_reuse_maps;
> }
> + if (is_prefix(*argv, "xdpmeta")) {
> + cur_ifindex = &meta_ifindex;
> + NEXT_ARG();
> + } else {
> + cur_ifindex = &offload_ifindex;
> + }
> if (!REQ_ARGS(1))
> goto err_free_reuse_maps;
>
> - ifindex = if_nametoindex(*argv);
> - if (!ifindex) {
> + *cur_ifindex = if_nametoindex(*argv);
> + if (!(*cur_ifindex)) {
> p_err("unrecognized netdevice '%s': %s",
> *argv, strerror(errno));
> goto err_free_reuse_maps;
> @@ -1671,7 +1680,12 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> goto err_close_obj;
> }
>
> - bpf_program__set_ifindex(pos, ifindex);
> + if (prog_type == BPF_PROG_TYPE_XDP && meta_ifindex) {
> + bpf_program__set_flags(pos, BPF_F_XDP_DEV_BOUND_ONLY);
> + bpf_program__set_ifindex(pos, meta_ifindex);
> + } else {
> + bpf_program__set_ifindex(pos, offload_ifindex);
> + }
> if (bpf_program__type(pos) != prog_type)
> bpf_program__set_type(pos, prog_type);
> bpf_program__set_expected_attach_type(pos, expected_attach_type);
> @@ -1709,7 +1723,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> idx = 0;
> bpf_object__for_each_map(map, obj) {
> if (bpf_map__type(map) != BPF_MAP_TYPE_PERF_EVENT_ARRAY)
> - bpf_map__set_ifindex(map, ifindex);
> + bpf_map__set_ifindex(map, offload_ifindex);
>
> if (j < old_map_fds && idx == map_replace[j].idx) {
> err = bpf_map__reuse_fd(map, map_replace[j++].fd);

Could you please also update the following items:

- The usage message for "bpftool prog load" near the end of prog.c

- The related doc in Documentation/bpftool-prog.rst (command summary
near the top, and detailed description later in the doc)

- Bash completion (for keyword "dev", look for "_sysfs_get_netdevs" in
bash-completion/bpftool). I'm happy to help with this one if necessary.

Thanks,
Quentin

2023-05-12 13:55:45

by Larysa Zaremba

[permalink] [raw]
Subject: Re: [PATCH bpf-next] bpftool: specify XDP Hints ifname when loading program

On Fri, May 12, 2023 at 11:23:00AM +0100, Quentin Monnet wrote:
> 2023-05-11 17:13 UTC+0200 ~ Larysa Zaremba <[email protected]>
> > Add ability to specify a network interface used to resolve
> > XDP Hints kfuncs when loading program through bpftool.
> >
> > Usage:
> > bpftool prog load <bpf_obj_path> <pin_path> dev xdpmeta <ifname>
>
> Thanks for this patch!
>
> Regarding the command-line syntax, I'm not a big fan of the optional
> sub-keyword for the device for XDP hints. I must admit I had not
> anticipated other another use for the "dev" keyword. Instead, have you
> considered one of the following:
>
> 1) Adding a different keyword ("xdpmeta_dev"?) and making it
> incompatible with "dev"
>
> 2) Another alternative would be adding a sub-keyword for offload too:
>
> bpftool p l [...] dev <[offload <ifname> | xdpmeta <ifname>]>
>
> If the ifname is provided with no sub-keyword, we would consider it for
> offload for legacy support, possibly warn that the syntax is deprecated.
>
> What do you think?
>

I think first option would look a little bit nicer, but I like the idea to
deprecate "dev <ifname>". In my current version, forgetting to add "xdpmeta"
resulted in not very descriptive errors, this may confuse new users. So what
about:

bpftool prog load [...] xdpmeta_dev/offload_dev <ifname>

"dev <ifname>" syntax would still work, but with a big warning, like this:

'bpftool prog [...] dev <ifname>' syntax is deprecated. Going further, please
use 'offload_dev <ifname>' to offload program to device. For XDP hints
applications, use 'xdpmeta_dev <ifname>'.

> >
> > Signed-off-by: Larysa Zaremba <[email protected]>
> > ---
> > tools/bpf/bpftool/prog.c | 28 +++++++++++++++++++++-------
> > 1 file changed, 21 insertions(+), 7 deletions(-)
> >
> > diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
> > index 91b6075b2db3..a9cb96d99277 100644
> > --- a/tools/bpf/bpftool/prog.c
> > +++ b/tools/bpf/bpftool/prog.c
> > @@ -1517,12 +1517,13 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> > struct bpf_program *prog = NULL, *pos;
> > unsigned int old_map_fds = 0;
> > const char *pinmaps = NULL;
> > + __u32 offload_ifindex = 0;
> > bool auto_attach = false;
> > + __u32 meta_ifindex = 0;
> > struct bpf_object *obj;
> > struct bpf_map *map;
> > const char *pinfile;
> > unsigned int i, j;
> > - __u32 ifindex = 0;
> > const char *file;
> > int idx, err;
> >
> > @@ -1614,17 +1615,25 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> > map_replace[old_map_fds].fd = fd;
> > old_map_fds++;
> > } else if (is_prefix(*argv, "dev")) {
> > + __u32 *cur_ifindex;
> > +
> > NEXT_ARG();
> >
> > - if (ifindex) {
> > - p_err("offload device already specified");
> > + if (offload_ifindex || meta_ifindex) {
> > + p_err("device already specified");
>
> I'd add a note to tell somehow that offload and XDP hints are mutually
> exclusive. I suspect not all users understand these well.

Ok, will do.

>
> > goto err_free_reuse_maps;
> > }
> > + if (is_prefix(*argv, "xdpmeta")) {
> > + cur_ifindex = &meta_ifindex;
> > + NEXT_ARG();
> > + } else {
> > + cur_ifindex = &offload_ifindex;
> > + }
> > if (!REQ_ARGS(1))
> > goto err_free_reuse_maps;
> >
> > - ifindex = if_nametoindex(*argv);
> > - if (!ifindex) {
> > + *cur_ifindex = if_nametoindex(*argv);
> > + if (!(*cur_ifindex)) {
> > p_err("unrecognized netdevice '%s': %s",
> > *argv, strerror(errno));
> > goto err_free_reuse_maps;
> > @@ -1671,7 +1680,12 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> > goto err_close_obj;
> > }
> >
> > - bpf_program__set_ifindex(pos, ifindex);
> > + if (prog_type == BPF_PROG_TYPE_XDP && meta_ifindex) {
> > + bpf_program__set_flags(pos, BPF_F_XDP_DEV_BOUND_ONLY);
> > + bpf_program__set_ifindex(pos, meta_ifindex);
> > + } else {
> > + bpf_program__set_ifindex(pos, offload_ifindex);
> > + }
> > if (bpf_program__type(pos) != prog_type)
> > bpf_program__set_type(pos, prog_type);
> > bpf_program__set_expected_attach_type(pos, expected_attach_type);
> > @@ -1709,7 +1723,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> > idx = 0;
> > bpf_object__for_each_map(map, obj) {
> > if (bpf_map__type(map) != BPF_MAP_TYPE_PERF_EVENT_ARRAY)
> > - bpf_map__set_ifindex(map, ifindex);
> > + bpf_map__set_ifindex(map, offload_ifindex);
> >
> > if (j < old_map_fds && idx == map_replace[j].idx) {
> > err = bpf_map__reuse_fd(map, map_replace[j++].fd);
>
> Could you please also update the following items:
>
> - The usage message for "bpftool prog load" near the end of prog.c
>
> - The related doc in Documentation/bpftool-prog.rst (command summary
> near the top, and detailed description later in the doc)
>
> - Bash completion (for keyword "dev", look for "_sysfs_get_netdevs" in
> bash-completion/bpftool). I'm happy to help with this one if necessary.

Will do all the above in v2.

>
> Thanks,
> Quentin

2023-05-15 16:43:31

by Niklas Söderlund

[permalink] [raw]
Subject: Re: [PATCH bpf-next] bpftool: specify XDP Hints ifname when loading program

On 2023-05-12 15:36:47 +0200, Larysa Zaremba wrote:
> [You don't often get email from [email protected]. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>
> On Fri, May 12, 2023 at 11:23:00AM +0100, Quentin Monnet wrote:
> > 2023-05-11 17:13 UTC+0200 ~ Larysa Zaremba <[email protected]>
> > > Add ability to specify a network interface used to resolve
> > > XDP Hints kfuncs when loading program through bpftool.
> > >
> > > Usage:
> > > bpftool prog load <bpf_obj_path> <pin_path> dev xdpmeta <ifname>
> >
> > Thanks for this patch!
> >
> > Regarding the command-line syntax, I'm not a big fan of the optional
> > sub-keyword for the device for XDP hints. I must admit I had not
> > anticipated other another use for the "dev" keyword. Instead, have you
> > considered one of the following:
> >
> > 1) Adding a different keyword ("xdpmeta_dev"?) and making it
> > incompatible with "dev"
> >
> > 2) Another alternative would be adding a sub-keyword for offload too:
> >
> > bpftool p l [...] dev <[offload <ifname> | xdpmeta <ifname>]>
> >
> > If the ifname is provided with no sub-keyword, we would consider it for
> > offload for legacy support, possibly warn that the syntax is deprecated.
> >
> > What do you think?
> >
>
> I think first option would look a little bit nicer, but I like the idea to
> deprecate "dev <ifname>". In my current version, forgetting to add "xdpmeta"
> resulted in not very descriptive errors, this may confuse new users. So what
> about:

I agree the first option looks a little bit nicer, but I think both
options would work.

>
> bpftool prog load [...] xdpmeta_dev/offload_dev <ifname>
>
> "dev <ifname>" syntax would still work, but with a big warning, like this:
>
> 'bpftool prog [...] dev <ifname>' syntax is deprecated. Going further, please
> use 'offload_dev <ifname>' to offload program to device. For XDP hints
> applications, use 'xdpmeta_dev <ifname>'.
>
> > >
> > > Signed-off-by: Larysa Zaremba <[email protected]>
> > > ---
> > > tools/bpf/bpftool/prog.c | 28 +++++++++++++++++++++-------
> > > 1 file changed, 21 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
> > > index 91b6075b2db3..a9cb96d99277 100644
> > > --- a/tools/bpf/bpftool/prog.c
> > > +++ b/tools/bpf/bpftool/prog.c
> > > @@ -1517,12 +1517,13 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> > > struct bpf_program *prog = NULL, *pos;
> > > unsigned int old_map_fds = 0;
> > > const char *pinmaps = NULL;
> > > + __u32 offload_ifindex = 0;
> > > bool auto_attach = false;
> > > + __u32 meta_ifindex = 0;
> > > struct bpf_object *obj;
> > > struct bpf_map *map;
> > > const char *pinfile;
> > > unsigned int i, j;
> > > - __u32 ifindex = 0;
> > > const char *file;
> > > int idx, err;
> > >
> > > @@ -1614,17 +1615,25 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> > > map_replace[old_map_fds].fd = fd;
> > > old_map_fds++;
> > > } else if (is_prefix(*argv, "dev")) {
> > > + __u32 *cur_ifindex;
> > > +
> > > NEXT_ARG();
> > >
> > > - if (ifindex) {
> > > - p_err("offload device already specified");
> > > + if (offload_ifindex || meta_ifindex) {
> > > + p_err("device already specified");
> >
> > I'd add a note to tell somehow that offload and XDP hints are mutually
> > exclusive. I suspect not all users understand these well.
>
> Ok, will do.
>
> >
> > > goto err_free_reuse_maps;
> > > }
> > > + if (is_prefix(*argv, "xdpmeta")) {
> > > + cur_ifindex = &meta_ifindex;
> > > + NEXT_ARG();
> > > + } else {
> > > + cur_ifindex = &offload_ifindex;
> > > + }
> > > if (!REQ_ARGS(1))
> > > goto err_free_reuse_maps;
> > >
> > > - ifindex = if_nametoindex(*argv);
> > > - if (!ifindex) {
> > > + *cur_ifindex = if_nametoindex(*argv);
> > > + if (!(*cur_ifindex)) {
> > > p_err("unrecognized netdevice '%s': %s",
> > > *argv, strerror(errno));
> > > goto err_free_reuse_maps;
> > > @@ -1671,7 +1680,12 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> > > goto err_close_obj;
> > > }
> > >
> > > - bpf_program__set_ifindex(pos, ifindex);
> > > + if (prog_type == BPF_PROG_TYPE_XDP && meta_ifindex) {
> > > + bpf_program__set_flags(pos, BPF_F_XDP_DEV_BOUND_ONLY);
> > > + bpf_program__set_ifindex(pos, meta_ifindex);
> > > + } else {
> > > + bpf_program__set_ifindex(pos, offload_ifindex);
> > > + }
> > > if (bpf_program__type(pos) != prog_type)
> > > bpf_program__set_type(pos, prog_type);
> > > bpf_program__set_expected_attach_type(pos, expected_attach_type);
> > > @@ -1709,7 +1723,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> > > idx = 0;
> > > bpf_object__for_each_map(map, obj) {
> > > if (bpf_map__type(map) != BPF_MAP_TYPE_PERF_EVENT_ARRAY)
> > > - bpf_map__set_ifindex(map, ifindex);
> > > + bpf_map__set_ifindex(map, offload_ifindex);
> > >
> > > if (j < old_map_fds && idx == map_replace[j].idx) {
> > > err = bpf_map__reuse_fd(map, map_replace[j++].fd);
> >
> > Could you please also update the following items:
> >
> > - The usage message for "bpftool prog load" near the end of prog.c
> >
> > - The related doc in Documentation/bpftool-prog.rst (command summary
> > near the top, and detailed description later in the doc)
> >
> > - Bash completion (for keyword "dev", look for "_sysfs_get_netdevs" in
> > bash-completion/bpftool). I'm happy to help with this one if necessary.
>
> Will do all the above in v2.
>
> >
> > Thanks,
> > Quentin

--
Kind Regards,
Niklas Söderlund

2023-05-15 17:32:09

by Quentin Monnet

[permalink] [raw]
Subject: Re: [PATCH bpf-next] bpftool: specify XDP Hints ifname when loading program

2023-05-15 18:30 UTC+0200 ~ Niklas Söderlund <[email protected]>
> On 2023-05-12 15:36:47 +0200, Larysa Zaremba wrote:
>> [You don't often get email from [email protected]. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>>
>> On Fri, May 12, 2023 at 11:23:00AM +0100, Quentin Monnet wrote:
>>> 2023-05-11 17:13 UTC+0200 ~ Larysa Zaremba <[email protected]>
>>>> Add ability to specify a network interface used to resolve
>>>> XDP Hints kfuncs when loading program through bpftool.
>>>>
>>>> Usage:
>>>> bpftool prog load <bpf_obj_path> <pin_path> dev xdpmeta <ifname>
>>>
>>> Thanks for this patch!
>>>
>>> Regarding the command-line syntax, I'm not a big fan of the optional
>>> sub-keyword for the device for XDP hints. I must admit I had not
>>> anticipated other another use for the "dev" keyword. Instead, have you
>>> considered one of the following:
>>>
>>> 1) Adding a different keyword ("xdpmeta_dev"?) and making it
>>> incompatible with "dev"
>>>
>>> 2) Another alternative would be adding a sub-keyword for offload too:
>>>
>>> bpftool p l [...] dev <[offload <ifname> | xdpmeta <ifname>]>
>>>
>>> If the ifname is provided with no sub-keyword, we would consider it for
>>> offload for legacy support, possibly warn that the syntax is deprecated.
>>>
>>> What do you think?
>>>
>>
>> I think first option would look a little bit nicer, but I like the idea to
>> deprecate "dev <ifname>". In my current version, forgetting to add "xdpmeta"
>> resulted in not very descriptive errors, this may confuse new users. So what
>> about:
>
> I agree the first option looks a little bit nicer, but I think both
> options would work.
>
>>
>> bpftool prog load [...] xdpmeta_dev/offload_dev <ifname>
>>
>> "dev <ifname>" syntax would still work, but with a big warning, like this:
>>
>> 'bpftool prog [...] dev <ifname>' syntax is deprecated. Going further, please
>> use 'offload_dev <ifname>' to offload program to device. For XDP hints
>> applications, use 'xdpmeta_dev <ifname>'.

OK let's go with this

Thanks,
Quentin