bcc-python: support attach_func() and detach_func() #3479
Conversation
chenyuezhou
requested review from
4ast,
brendangregg,
drzaeus77,
goldshtn and
yonghong-song
as code owners
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[buildbot, test this please] |
docs/reference_guide.md
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| @@ -1847,6 +1849,42 @@ Examples in situ: | |||
| [search /examples](https://github.com/iovisor/bcc/search?q=attach_xdp+path%3Aexamples+language%3Apython&type=Code), | |||
| [search /tools](https://github.com/iovisor/bcc/search?q=attach_xdp+path%3Atools+language%3Apython&type=Code) | |||
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| ### 10. attach_func() | |||
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| Syntax: ```BPF.attach_func(fn, attach_type [, attachable_fd [, flags)``` | |||
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I think we can have a signature like
BPF.attach_func(fn, attachable_fd, attach_type [, flags])
Basically make attachable_fd mandatory and flags optional for python APIs.
The only case that an attchable_fd is not needed (must be 0) is for net_namespace. I think it is okay to require it and this makes argument sequence consistent with C++ APIs.
docs/reference_guide.md
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| Syntax: ```BPF.attach_func(fn, attach_type [, attachable_fd [, flags)``` | ||
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| Attaches a BPF function of the specified type. |
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Attaches a BPF function of the specified type to a particular attachable_fd. if the attach_type is BPF_FLOW_DISSECTOR, the function is expected to attach to current net namespace and attachable_fd must be 0.
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thanks, adjusted.
docs/reference_guide.md
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| ### 11. detach_func() | ||
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| Syntax: ```BPF.detach_func(fn, detach_type [, target_fd)``` |
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Again, let us do BPF.detach_func(fn, attachable_fd, attach_type), similar to C++ APIs.
examples/networking/sockmap.py
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| func_sock_redir = bpf.load_func("bpf_redir", bpf.SK_MSG) | ||
| # raise if error | ||
| fd = os.open(args.cgroup, os.O_RDONLY) | ||
| map_fd = lib.bpf_table_fd(bpf.module, "sock_hash") |
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I got a failure like below with python3.6,
$ sudo python3.6 sockmap.py -c /sys/fs/cgroup/system.slice/tmp.service/
Traceback (most recent call last):
File "sockmap.py", line 115, in <module>
map_fd = lib.bpf_table_fd(bpf.module, "sock_hash")
ctypes.ArgumentError: argument 2: <class 'TypeError'>: wrong type
Changing "sock_hash" to b"sock_hash" fixed the issue. Probably some python byte array thing.
| if not isinstance(fn, BPF.Function): | ||
| raise Exception("arg 1 must be of type BPF.Function") | ||
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| res = lib.bpf_prog_attach(fn.fd, attachable_fd, attach_type, flags) |
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Probably we should add bpf_prog_attach/detach2 to libbcc.py to make it explicit?
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[buildbot, test this please] |
docs/reference_guide.md
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| @@ -1847,6 +1849,42 @@ Examples in situ: | |||
| [search /examples](https://github.com/iovisor/bcc/search?q=attach_xdp+path%3Aexamples+language%3Apython&type=Code), | |||
| [search /tools](https://github.com/iovisor/bcc/search?q=attach_xdp+path%3Atools+language%3Apython&type=Code) | |||
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| ### 10. attach_func() | |||
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| Syntax: ```BPF.attach_func(fn, attachable_fd, attach_type [, flags)``` | |||
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I prefer we add ']' after '[, flags', so change to [, flags]?
examples/networking/sockmap.py
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| examples = """examples: | ||
| ./sockmap.py /root/cgroup # attach to /root/cgroup |
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./sockmap.py -c /root/cgroup ?
examples/networking/sockmap.py
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| bpf_text = ''' | ||
| #include <net/sock.h> | ||
| #include <bcc/proto.h> |
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#include <bcc/proto.h> is not needed.
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[buildbot, test this please] |
In iovisor#3479, the `bpf_attach_type` enum was pulled into the `BPF` class so that its members could be used in `attach_func` and `detach_func` functions introduced to the Python API. Unfortunately this caused a redefinition of BPF.XDP, which was similarly pulled in from `bpf_prog_type` enum, thus breaking program loading (iovisor#3489). Let's pull these enum- and flag-type class variables out into their own wrapper classes. For backwards compatibility, keep them all (except for `bpf_attach_type`, which was merged 2 days ago) defined in the BPF class, but add a comment to not continue doing this.
In #3479, the `bpf_attach_type` enum was pulled into the `BPF` class so that its members could be used in `attach_func` and `detach_func` functions introduced to the Python API. Unfortunately this caused a redefinition of BPF.XDP, which was similarly pulled in from `bpf_prog_type` enum, thus breaking program loading (#3489). Let's pull these enum- and flag-type class variables out into their own wrapper classes. For backwards compatibility, keep them all (except for `bpf_attach_type`, which was merged 2 days ago) defined in the BPF class, but add a comment to not continue doing this.
In iovisor#3479, the `bpf_attach_type` enum was pulled into the `BPF` class so that its members could be used in `attach_func` and `detach_func` functions introduced to the Python API. Unfortunately this caused a redefinition of BPF.XDP, which was similarly pulled in from `bpf_prog_type` enum, thus breaking program loading (iovisor#3489). Let's pull these enum- and flag-type class variables out into their own wrapper classes. For backwards compatibility, keep them all (except for `bpf_attach_type`, which was merged 2 days ago) defined in the BPF class, but add a comment to not continue doing this.
Add
attach_func()anddetach_func().Add a usage sample.(
sockmap.py)