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bpf: add frags support to xdp copy helpers

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This patch adds support for frags for the following helpers:
  - bpf_xdp_output()
  - bpf_perf_event_output()

Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/340b4a99cdc24337b40eaf8bb597f9f9e7b0373e.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Eelco Chaudron 2022-01-21 11:09:56 +01:00 committed by Alexei Starovoitov
parent bf25146a55
commit d99173027d
4 changed files with 137 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
kernel/trace/bpf_trace.c
View File

@ -1562,6 +1562,7 @@ static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = {
extern const struct bpf_func_proto bpf_skb_output_proto;
extern const struct bpf_func_proto bpf_xdp_output_proto;
extern const struct bpf_func_proto bpf_xdp_get_buff_len_trace_proto;
BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args,
struct bpf_map *, map, u64, flags)
@ -1661,6 +1662,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_sock_from_file_proto;
case BPF_FUNC_get_socket_cookie:
return &bpf_get_socket_ptr_cookie_proto;
case BPF_FUNC_xdp_get_buff_len:
return &bpf_xdp_get_buff_len_trace_proto;
#endif
case BPF_FUNC_seq_printf:
return prog->expected_attach_type == BPF_TRACE_ITER ?

57
net/core/filter.c
View File

@ -3796,6 +3796,15 @@ static const struct bpf_func_proto bpf_xdp_get_buff_len_proto = {
.arg1_type = ARG_PTR_TO_CTX,
};
BTF_ID_LIST_SINGLE(bpf_xdp_get_buff_len_bpf_ids, struct, xdp_buff)
const struct bpf_func_proto bpf_xdp_get_buff_len_trace_proto = {
.func = bpf_xdp_get_buff_len,
.gpl_only = false,
.arg1_type = ARG_PTR_TO_BTF_ID,
.arg1_btf_id = &bpf_xdp_get_buff_len_bpf_ids[0],
};
static unsigned long xdp_get_metalen(const struct xdp_buff *xdp)
{
return xdp_data_meta_unsupported(xdp) ? 0 :
@ -4668,10 +4677,48 @@ static const struct bpf_func_proto bpf_sk_ancestor_cgroup_id_proto = {
};
#endif
static unsigned long bpf_xdp_copy(void *dst_buff, const void *src_buff,
static unsigned long bpf_xdp_copy(void *dst_buff, const void *ctx,
unsigned long off, unsigned long len)
{
memcpy(dst_buff, src_buff + off, len);
struct xdp_buff *xdp = (struct xdp_buff *)ctx;
unsigned long ptr_len, ptr_off = 0;
skb_frag_t *next_frag, *end_frag;
struct skb_shared_info *sinfo;
u8 *ptr_buf;
if (likely(xdp->data_end - xdp->data >= off + len)) {
memcpy(dst_buff, xdp->data + off, len);
return 0;
}
sinfo = xdp_get_shared_info_from_buff(xdp);
end_frag = &sinfo->frags[sinfo->nr_frags];
next_frag = &sinfo->frags[0];
ptr_len = xdp->data_end - xdp->data;
ptr_buf = xdp->data;
while (true) {
if (off < ptr_off + ptr_len) {
unsigned long copy_off = off - ptr_off;
unsigned long copy_len = min(len, ptr_len - copy_off);
memcpy(dst_buff, ptr_buf + copy_off, copy_len);
off += copy_len;
len -= copy_len;
dst_buff += copy_len;
}
if (!len || next_frag == end_frag)
break;
ptr_off += ptr_len;
ptr_buf = skb_frag_address(next_frag);
ptr_len = skb_frag_size(next_frag);
next_frag++;
}
return 0;
}
@ -4682,11 +4729,11 @@ BPF_CALL_5(bpf_xdp_event_output, struct xdp_buff *, xdp, struct bpf_map *, map,
if (unlikely(flags & ~(BPF_F_CTXLEN_MASK | BPF_F_INDEX_MASK)))
return -EINVAL;
if (unlikely(!xdp ||
xdp_size > (unsigned long)(xdp->data_end - xdp->data)))
if (unlikely(!xdp || xdp_size > xdp_get_buff_len(xdp)))
return -EFAULT;
return bpf_event_output(map, flags, meta, meta_size, xdp->data,
return bpf_event_output(map, flags, meta, meta_size, xdp,
xdp_size, bpf_xdp_copy);
}

111
tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c
View File

@ -10,28 +10,97 @@ struct meta {
int pkt_len;
};
struct test_ctx_s {
bool passed;
int pkt_size;
};
struct test_ctx_s test_ctx;
static void on_sample(void *ctx, int cpu, void *data, __u32 size)
{
struct meta *meta = (struct meta *)data;
struct ipv4_packet *trace_pkt_v4 = data + sizeof(*meta);
unsigned char *raw_pkt = data + sizeof(*meta);
struct test_ctx_s *tst_ctx = ctx;
ASSERT_GE(size, sizeof(pkt_v4) + sizeof(*meta), "check_size");
ASSERT_EQ(meta->ifindex, if_nametoindex("lo"), "check_meta_ifindex");
ASSERT_EQ(meta->pkt_len, sizeof(pkt_v4), "check_meta_pkt_len");
ASSERT_EQ(meta->pkt_len, tst_ctx->pkt_size, "check_meta_pkt_len");
ASSERT_EQ(memcmp(trace_pkt_v4, &pkt_v4, sizeof(pkt_v4)), 0,
"check_packet_content");
*(bool *)ctx = true;
if (meta->pkt_len > sizeof(pkt_v4)) {
for (int i = 0; i < meta->pkt_len - sizeof(pkt_v4); i++)
ASSERT_EQ(raw_pkt[i + sizeof(pkt_v4)], (unsigned char)i,
"check_packet_content");
}
tst_ctx->passed = true;
}
#define BUF_SZ 9000
static void run_xdp_bpf2bpf_pkt_size(int pkt_fd, struct perf_buffer *pb,
struct test_xdp_bpf2bpf *ftrace_skel,
int pkt_size)
{
__u32 duration = 0, retval, size;
__u8 *buf, *buf_in;
int err;
if (!ASSERT_LE(pkt_size, BUF_SZ, "pkt_size") ||
!ASSERT_GE(pkt_size, sizeof(pkt_v4), "pkt_size"))
return;
buf_in = malloc(BUF_SZ);
if (!ASSERT_OK_PTR(buf_in, "buf_in malloc()"))
return;
buf = malloc(BUF_SZ);
if (!ASSERT_OK_PTR(buf, "buf malloc()")) {
free(buf_in);
return;
}
test_ctx.passed = false;
test_ctx.pkt_size = pkt_size;
memcpy(buf_in, &pkt_v4, sizeof(pkt_v4));
if (pkt_size > sizeof(pkt_v4)) {
for (int i = 0; i < (pkt_size - sizeof(pkt_v4)); i++)
buf_in[i + sizeof(pkt_v4)] = i;
}
/* Run test program */
err = bpf_prog_test_run(pkt_fd, 1, buf_in, pkt_size,
buf, &size, &retval, &duration);
ASSERT_OK(err, "ipv4");
ASSERT_EQ(retval, XDP_PASS, "ipv4 retval");
ASSERT_EQ(size, pkt_size, "ipv4 size");
/* Make sure bpf_xdp_output() was triggered and it sent the expected
* data to the perf ring buffer.
*/
err = perf_buffer__poll(pb, 100);
ASSERT_GE(err, 0, "perf_buffer__poll");
ASSERT_TRUE(test_ctx.passed, "test passed");
/* Verify test results */
ASSERT_EQ(ftrace_skel->bss->test_result_fentry, if_nametoindex("lo"),
"fentry result");
ASSERT_EQ(ftrace_skel->bss->test_result_fexit, XDP_PASS, "fexit result");
free(buf);
free(buf_in);
}
void test_xdp_bpf2bpf(void)
{
__u32 duration = 0, retval, size;
char buf[128];
int err, pkt_fd, map_fd;
bool passed = false;
struct iphdr iph;
struct iptnl_info value4 = {.family = AF_INET};
int pkt_sizes[] = {sizeof(pkt_v4), 1024, 4100, 8200};
struct iptnl_info value4 = {.family = AF_INET6};
struct test_xdp *pkt_skel = NULL;
struct test_xdp_bpf2bpf *ftrace_skel = NULL;
struct vip key4 = {.protocol = 6, .family = AF_INET};
@ -73,32 +142,14 @@ void test_xdp_bpf2bpf(void)
goto out;
/* Set up perf buffer */
pb = perf_buffer__new(bpf_map__fd(ftrace_skel->maps.perf_buf_map), 1,
on_sample, NULL, &passed, NULL);
pb = perf_buffer__new(bpf_map__fd(ftrace_skel->maps.perf_buf_map), 8,
on_sample, NULL, &test_ctx, NULL);
if (!ASSERT_OK_PTR(pb, "perf_buf__new"))
goto out;
/* Run test program */
err = bpf_prog_test_run(pkt_fd, 1, &pkt_v4, sizeof(pkt_v4),
buf, &size, &retval, &duration);
memcpy(&iph, buf + sizeof(struct ethhdr), sizeof(iph));
ASSERT_OK(err, "ipv4");
ASSERT_EQ(retval, XDP_TX, "ipv4 retval");
ASSERT_EQ(size, 74, "ipv4 size");
ASSERT_EQ(iph.protocol, IPPROTO_IPIP, "ipv4 proto");
/* Make sure bpf_xdp_output() was triggered and it sent the expected
* data to the perf ring buffer.
*/
err = perf_buffer__poll(pb, 100);
ASSERT_GE(err, 0, "perf_buffer__poll");
ASSERT_TRUE(passed, "test passed");
/* Verify test results */
ASSERT_EQ(ftrace_skel->bss->test_result_fentry, if_nametoindex("lo"),
"fentry result");
ASSERT_EQ(ftrace_skel->bss->test_result_fexit, XDP_TX, "fexit result");
for (int i = 0; i < ARRAY_SIZE(pkt_sizes); i++)
run_xdp_bpf2bpf_pkt_size(pkt_fd, pb, ftrace_skel,
pkt_sizes[i]);
out:
perf_buffer__free(pb);
test_xdp__destroy(pkt_skel);

2
tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
View File

@ -49,7 +49,7 @@ int BPF_PROG(trace_on_entry, struct xdp_buff *xdp)
void *data = (void *)(long)xdp->data;
meta.ifindex = xdp->rxq->dev->ifindex;
meta.pkt_len = data_end - data;
meta.pkt_len = bpf_xdp_get_buff_len((struct xdp_md *)xdp);
bpf_xdp_output(xdp, &perf_buf_map,
((__u64) meta.pkt_len << 32) |
BPF_F_CURRENT_CPU,