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charset=utf-8 Content-Transfer-Encoding: 7bit Zijian Zhang wrote: > On 11/6/24 7:41 PM, Cong Wang wrote: > > From: Cong Wang > > > > As requested by Daniel, we need to add a selftest to cover > > bpf_skb_change_tail() cases in skb_verdict. Here we test trimming, > > growing and error cases, and validate its expected return values. > > > > Cc: John Fastabend > > Cc: Daniel Borkmann > > Cc: Zijian Zhang > > Signed-off-by: Cong Wang > > --- > > .../selftests/bpf/prog_tests/sockmap_basic.c | 51 +++++++++++++++++++ > > .../bpf/progs/test_sockmap_change_tail.c | 40 +++++++++++++++ > > 2 files changed, 91 insertions(+) > > create mode 100644 tools/testing/selftests/bpf/progs/test_sockmap_change_tail.c > > > > diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c > > index 82bfb266741c..fe735fced836 100644 > > --- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c > > +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c > > @@ -12,6 +12,7 @@ > > #include "test_sockmap_progs_query.skel.h" > > #include "test_sockmap_pass_prog.skel.h" > > #include "test_sockmap_drop_prog.skel.h" > > +#include "test_sockmap_change_tail.skel.h" > > #include "bpf_iter_sockmap.skel.h" > > > > #include "sockmap_helpers.h" > > @@ -562,6 +563,54 @@ static void test_sockmap_skb_verdict_fionread(bool pass_prog) > > test_sockmap_drop_prog__destroy(drop); > > } > > > > +static void test_sockmap_skb_verdict_change_tail(void) > > +{ > > + struct test_sockmap_change_tail *skel; > > + int err, map, verdict; > > + int c1, p1, sent, recvd; > > + int zero = 0; > > + char b[3]; > > + > > + skel = test_sockmap_change_tail__open_and_load(); > > + if (!ASSERT_OK_PTR(skel, "open_and_load")) > > + return; > > + verdict = bpf_program__fd(skel->progs.prog_skb_verdict); > > + map = bpf_map__fd(skel->maps.sock_map_rx); > > + > > + err = bpf_prog_attach(verdict, map, BPF_SK_SKB_STREAM_VERDICT, 0); > > + if (!ASSERT_OK(err, "bpf_prog_attach")) > > + goto out; > > + err = create_pair(AF_INET, SOCK_STREAM, &c1, &p1); > > + if (!ASSERT_OK(err, "create_pair()")) > > + goto out; > > + err = bpf_map_update_elem(map, &zero, &c1, BPF_NOEXIST); > > + if (!ASSERT_OK(err, "bpf_map_update_elem(c1)")) > > + goto out_close; > > + sent = xsend(p1, "Tr", 2, 0); > > + ASSERT_EQ(sent, 2, "xsend(p1)"); > > + recvd = recv(c1, b, 2, 0); > > + ASSERT_EQ(recvd, 1, "recv(c1)"); > > + ASSERT_EQ(skel->data->change_tail_ret, 0, "change_tail_ret"); > > + > > + sent = xsend(p1, "G", 1, 0); > > + ASSERT_EQ(sent, 1, "xsend(p1)"); > > + recvd = recv(c1, b, 2, 0); > > + ASSERT_EQ(recvd, 2, "recv(c1)"); > > + ASSERT_EQ(skel->data->change_tail_ret, 0, "change_tail_ret"); > > + > > + sent = xsend(p1, "E", 1, 0); > > + ASSERT_EQ(sent, 1, "xsend(p1)"); > > + recvd = recv(c1, b, 1, 0); > > + ASSERT_EQ(recvd, 1, "recv(c1)"); > > + ASSERT_EQ(skel->data->change_tail_ret, -EINVAL, "change_tail_ret"); > > + > > +out_close: > > + close(c1); > > + close(p1); > > +out: > > + test_sockmap_change_tail__destroy(skel); > > +} > > + > > static void test_sockmap_skb_verdict_peek_helper(int map) > > { > > int err, c1, p1, zero = 0, sent, recvd, avail; > > @@ -927,6 +976,8 @@ void test_sockmap_basic(void) > > test_sockmap_skb_verdict_fionread(true); > > if (test__start_subtest("sockmap skb_verdict fionread on drop")) > > test_sockmap_skb_verdict_fionread(false); > > + if (test__start_subtest("sockmap skb_verdict change tail")) > > + test_sockmap_skb_verdict_change_tail(); > > if (test__start_subtest("sockmap skb_verdict msg_f_peek")) > > test_sockmap_skb_verdict_peek(); > > if (test__start_subtest("sockmap skb_verdict msg_f_peek with link")) > > diff --git a/tools/testing/selftests/bpf/progs/test_sockmap_change_tail.c b/tools/testing/selftests/bpf/progs/test_sockmap_change_tail.c > > new file mode 100644 > > index 000000000000..2796dd8545eb > > --- /dev/null > > +++ b/tools/testing/selftests/bpf/progs/test_sockmap_change_tail.c > > @@ -0,0 +1,40 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* Copyright (c) 2024 ByteDance */ > > +#include > > +#include > > + > > +struct { > > + __uint(type, BPF_MAP_TYPE_SOCKMAP); > > + __uint(max_entries, 1); > > + __type(key, int); > > + __type(value, int); > > +} sock_map_rx SEC(".maps"); > > + > > +long change_tail_ret = 1; > > + > > +SEC("sk_skb") > > +int prog_skb_verdict(struct __sk_buff *skb) > > +{ > > + char *data, *data_end; > > + > > + bpf_skb_pull_data(skb, 1); > > + data = (char *)(unsigned long)skb->data; > > + data_end = (char *)(unsigned long)skb->data_end; > > + > > + if (data + 1 > data_end) > > + return SK_PASS; > > + > > + if (data[0] == 'T') { /* Trim the packet */ > > + change_tail_ret = bpf_skb_change_tail(skb, skb->len - 1, 0); > > + return SK_PASS; > > + } else if (data[0] == 'G') { /* Grow the packet */ > > + change_tail_ret = bpf_skb_change_tail(skb, skb->len + 1, 0); > > + return SK_PASS; > > + } else if (data[0] == 'E') { /* Error */ > > + change_tail_ret = bpf_skb_change_tail(skb, 65535, 0); > > + return SK_PASS; > > + } > > + return SK_PASS; > > +} > > + > > +char _license[] SEC("license") = "GPL"; > > LGTM! > > I think it will be better if the test could also cover the case you > indicated in the first patch, where skb_transport_offset is a negative > value. > > Thanks, > Zijian > Hi Cong, I agree it would be great to see the skb_transport_offset is negative pattern. Could we add it? Thanks, John