After being able to add metadata to messages with sk_msg_push_data we
have also found it useful to be able to "pop" this metadata off before
sending it to applications in some cases. This series adds a new helper
sk_msg_pop_data() and the associated patches to add tests and tools/lib
support.
Thanks!
v2: Daniel caught that we missed adding sk_msg_pop_data to the changes
data helper so that the verifier ensures BPF programs revalidate
data after using this helper. Also improve documentation adding a
return description and using RST syntax per Quentin's comment. And
delta calculations for DROP with pop'd data (albeit a strange set
of operations for a program to be doing) had potential to be
incorrect possibly confusing user space applications, so fix it.
John Fastabend (3):
bpf: helper to pop data from messages
bpf: add msg_pop_data helper to tools
bpf: test_sockmap, add options for msg_pop_data() helper usage
include/uapi/linux/bpf.h | 13 +-
net/core/filter.c | 169 ++++++++++++++++++++++++
net/ipv4/tcp_bpf.c | 14 +-
tools/include/uapi/linux/bpf.h | 13 +-
tools/testing/selftests/bpf/bpf_helpers.h | 2 +
tools/testing/selftests/bpf/test_sockmap.c | 127 +++++++++++++++++-
tools/testing/selftests/bpf/test_sockmap_kern.h | 70 ++++++++--
7 files changed, 386 insertions(+), 22 deletions(-)
--
2.7.4
