This patchset is the 2nd in the dynptr series. The 1st can be found here [0].
This patchset adds skb and xdp type dynptrs, which have two main benefits for
packet parsing:
* allowing operations on sizes that are not statically known at
compile-time (eg variable-sized accesses).
* more ergonomic and less brittle iteration through data (eg does not need
manual if checking for being within bounds of data_end)
When comparing the differences in runtime for packet parsing without dynptrs
vs. with dynptrs for the more simple cases, there is no noticeable difference.
For the more complex cases where lengths are non-statically known at compile
time, there can be a significant speed-up when using dynptrs (eg a 2x speed up
for cls redirection). Patch 3 contains more details as well as examples of how
to use skb and xdp dynptrs.
[0]
https://lore.kernel.org/bpf/20220523210712.3641569-1-joannelkoong@xxxxxxxxx/
--
Changelog:
v7 = https://lore.kernel.org/bpf/20221021011510.1890852-1-joannelkoong@xxxxxxxxx/
v7 -> v8:
* Change helpers to kfuncs
* Add 2 new patches (1/5 and 2/5)
v6 = https://lore.kernel.org/bpf/20220907183129.745846-1-joannelkoong@xxxxxxxxx/
v6 -> v7
* Change bpf_dynptr_data() to return read-only data slices if the skb prog
is read-only (Martin)
* Add test "skb_invalid_write" to test that writes to rd-only data slices
are rejected
v5 = https://lore.kernel.org/bpf/20220831183224.3754305-1-joannelkoong@xxxxxxxxx/
v5 -> v6
* Address kernel test robot errors by static inlining
v4 = https://lore.kernel.org/bpf/20220822235649.2218031-1-joannelkoong@xxxxxxxxx/
v4 -> v5
* Address kernel test robot errors for configs w/out CONFIG_NET set
* For data slices, return PTR_TO_MEM instead of PTR_TO_PACKET (Kumar)
* Split selftests into subtests (Andrii)
* Remove insn patching. Use rdonly and rdwr protos for dynptr skb
construction (Andrii)
* bpf_dynptr_data() returns NULL for rd-only dynptrs. There will be a
separate bpf_dynptr_data_rdonly() added later (Andrii and Kumar)
v3 = https://lore.kernel.org/bpf/20220822193442.657638-1-joannelkoong@xxxxxxxxx/
v3 -> v4
* Forgot to commit --amend the kernel test robot error fixups
v2 = https://lore.kernel.org/bpf/20220811230501.2632393-1-joannelkoong@xxxxxxxxx/
v2 -> v3
* Fix kernel test robot build test errors
v1 = https://lore.kernel.org/bpf/20220726184706.954822-1-joannelkoong@xxxxxxxxx/
v1 -> v2
* Return data slices to rd-only skb dynptrs (Martin)
* bpf_dynptr_write allows writes to frags for skb dynptrs, but always
invalidates associated data slices (Martin)
* Use switch casing instead of ifs (Andrii)
* Use 0xFD for experimental kind number in the selftest (Zvi)
* Put selftest conversions w/ dynptrs into new files (Alexei)
* Add new selftest "test_cls_redirect_dynptr.c"
Joanne Koong (5):
bpf: Allow "sk_buff" and "xdp_buff" as valid kfunc arg types
bpf: Allow initializing dynptrs in kfuncs
bpf: Add skb dynptrs
bpf: Add xdp dynptrs
selftests/bpf: tests for using dynptrs to parse skb and xdp buffers
include/linux/bpf.h | 88 +-
include/linux/bpf_verifier.h | 3 -
include/linux/filter.h | 38 +
include/uapi/linux/bpf.h | 41 +-
kernel/bpf/btf.c | 22 +
kernel/bpf/helpers.c | 107 +-
kernel/bpf/verifier.c | 325 +++---
net/core/filter.c | 104 +-
tools/include/uapi/linux/bpf.h | 41 +-
.../selftests/bpf/prog_tests/cls_redirect.c | 25 +
.../testing/selftests/bpf/prog_tests/dynptr.c | 63 +-
.../selftests/bpf/prog_tests/l4lb_all.c | 2 +
.../bpf/prog_tests/parse_tcp_hdr_opt.c | 93 ++
.../selftests/bpf/prog_tests/xdp_attach.c | 11 +-
.../testing/selftests/bpf/progs/dynptr_fail.c | 124 +++
.../selftests/bpf/progs/dynptr_success.c | 28 +
.../bpf/progs/test_cls_redirect_dynptr.c | 973 ++++++++++++++++++
.../bpf/progs/test_l4lb_noinline_dynptr.c | 474 +++++++++
.../bpf/progs/test_parse_tcp_hdr_opt.c | 119 +++
.../bpf/progs/test_parse_tcp_hdr_opt_dynptr.c | 112 ++
.../selftests/bpf/progs/test_xdp_dynptr.c | 237 +++++
.../selftests/bpf/test_tcp_hdr_options.h | 1 +
22 files changed, 2825 insertions(+), 206 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/parse_tcp_hdr_opt.c
create mode 100644 tools/testing/selftests/bpf/progs/test_cls_redirect_dynptr.c
create mode 100644 tools/testing/selftests/bpf/progs/test_l4lb_noinline_dynptr.c
create mode 100644 tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt.c
create mode 100644 tools/testing/selftests/bpf/progs/test_parse_tcp_hdr_opt_dynptr.c
create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_dynptr.c
--
2.30.2
