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bpf: sockmap sample test for bpf_msg_pull_data
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This adds an option to test the msg_pull_data helper. This
uses two options txmsg_start and txmsg_end to let the user
specify start and end bytes to pull.

The options can be used with txmsg_apply, txmsg_cork options
as well as with any of the basic tests, txmsg, txmsg_redir and
txmsg_drop (plus noisy variants) to run pull_data inline with
those tests. By giving user direct control over the variables
we can easily do negative testing as well as positive tests.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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John Fastabend authored and Daniel Borkmann committed Mar 19, 2018
1 parent e6373ce commit 0dcbbf6
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Showing 4 changed files with 101 additions and 15 deletions.
79 changes: 65 additions & 14 deletions samples/sockmap/sockmap_kern.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -71,6 +71,14 @@ struct bpf_map_def SEC("maps") sock_cork_bytes = {
.max_entries = 1
};

struct bpf_map_def SEC("maps") sock_pull_bytes = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(int),
.value_size = sizeof(int),
.max_entries = 2
};


SEC("sk_skb1")
int bpf_prog1(struct __sk_buff *skb)
{
Expand Down Expand Up @@ -137,67 +145,104 @@ int bpf_sockmap(struct bpf_sock_ops *skops)
SEC("sk_msg1")
int bpf_prog4(struct sk_msg_md *msg)
{
int *bytes, zero = 0;
int *bytes, zero = 0, one = 1;
int *start, *end;

bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero);
if (bytes)
bpf_msg_apply_bytes(msg, *bytes);
bytes = bpf_map_lookup_elem(&sock_cork_bytes, &zero);
if (bytes)
bpf_msg_cork_bytes(msg, *bytes);
start = bpf_map_lookup_elem(&sock_pull_bytes, &zero);
end = bpf_map_lookup_elem(&sock_pull_bytes, &one);
if (start && end)
bpf_msg_pull_data(msg, *start, *end, 0);
return SK_PASS;
}

SEC("sk_msg2")
int bpf_prog5(struct sk_msg_md *msg)
{
void *data_end = (void *)(long) msg->data_end;
void *data = (void *)(long) msg->data;
int *bytes, err1 = -1, err2 = -1, zero = 0;
int err1 = -1, err2 = -1, zero = 0, one = 1;
int *bytes, *start, *end, len1, len2;

bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero);
if (bytes)
err1 = bpf_msg_apply_bytes(msg, *bytes);
bytes = bpf_map_lookup_elem(&sock_cork_bytes, &zero);
if (bytes)
err2 = bpf_msg_cork_bytes(msg, *bytes);
len1 = (__u64)msg->data_end - (__u64)msg->data;
start = bpf_map_lookup_elem(&sock_pull_bytes, &zero);
end = bpf_map_lookup_elem(&sock_pull_bytes, &one);
if (start && end) {
int err;

bpf_printk("sk_msg2: pull(%i:%i)\n",
start ? *start : 0, end ? *end : 0);
err = bpf_msg_pull_data(msg, *start, *end, 0);
if (err)
bpf_printk("sk_msg2: pull_data err %i\n",
err);
len2 = (__u64)msg->data_end - (__u64)msg->data;
bpf_printk("sk_msg2: length update %i->%i\n",
len1, len2);
}
bpf_printk("sk_msg2: data length %i err1 %i err2 %i\n",
(__u64)data_end - (__u64)data, err1, err2);
len1, err1, err2);
return SK_PASS;
}

SEC("sk_msg3")
int bpf_prog6(struct sk_msg_md *msg)
{
void *data_end = (void *)(long) msg->data_end;
void *data = (void *)(long) msg->data;
int *bytes, zero = 0;
int *bytes, zero = 0, one = 1;
int *start, *end;

bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero);
if (bytes)
bpf_msg_apply_bytes(msg, *bytes);
bytes = bpf_map_lookup_elem(&sock_cork_bytes, &zero);
if (bytes)
bpf_msg_cork_bytes(msg, *bytes);
start = bpf_map_lookup_elem(&sock_pull_bytes, &zero);
end = bpf_map_lookup_elem(&sock_pull_bytes, &one);
if (start && end)
bpf_msg_pull_data(msg, *start, *end, 0);
return bpf_msg_redirect_map(msg, &sock_map_redir, zero, 0);
}

SEC("sk_msg4")
int bpf_prog7(struct sk_msg_md *msg)
{
void *data_end = (void *)(long) msg->data_end;
void *data = (void *)(long) msg->data;
int *bytes, err1 = 0, err2 = 0, zero = 0;
int err1 = 0, err2 = 0, zero = 0, one = 1;
int *bytes, *start, *end, len1, len2;

bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero);
if (bytes)
err1 = bpf_msg_apply_bytes(msg, *bytes);
bytes = bpf_map_lookup_elem(&sock_cork_bytes, &zero);
if (bytes)
err2 = bpf_msg_cork_bytes(msg, *bytes);

len1 = (__u64)msg->data_end - (__u64)msg->data;
start = bpf_map_lookup_elem(&sock_pull_bytes, &zero);
end = bpf_map_lookup_elem(&sock_pull_bytes, &one);
if (start && end) {
int err;

bpf_printk("sk_msg2: pull(%i:%i)\n",
start ? *start : 0, end ? *end : 0);
err = bpf_msg_pull_data(msg, *start, *end, 0);
if (err)
bpf_printk("sk_msg2: pull_data err %i\n",
err);
len2 = (__u64)msg->data_end - (__u64)msg->data;
bpf_printk("sk_msg2: length update %i->%i\n",
len1, len2);
}
bpf_printk("sk_msg3: redirect(%iB) err1=%i err2=%i\n",
(__u64)data_end - (__u64)data, err1, err2);
len1, err1, err2);
return bpf_msg_redirect_map(msg, &sock_map_redir, zero, 0);
}

Expand Down Expand Up @@ -239,14 +284,20 @@ int bpf_prog9(struct sk_msg_md *msg)
SEC("sk_msg7")
int bpf_prog10(struct sk_msg_md *msg)
{
int *bytes, zero = 0;
int *bytes, zero = 0, one = 1;
int *start, *end;

bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero);
if (bytes)
bpf_msg_apply_bytes(msg, *bytes);
bytes = bpf_map_lookup_elem(&sock_cork_bytes, &zero);
if (bytes)
bpf_msg_cork_bytes(msg, *bytes);
start = bpf_map_lookup_elem(&sock_pull_bytes, &zero);
end = bpf_map_lookup_elem(&sock_pull_bytes, &one);
if (start && end)
bpf_msg_pull_data(msg, *start, *end, 0);

return SK_DROP;
}

Expand Down
32 changes: 32 additions & 0 deletions samples/sockmap/sockmap_user.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -62,6 +62,8 @@ int txmsg_redir_noisy;
int txmsg_drop;
int txmsg_apply;
int txmsg_cork;
int txmsg_start;
int txmsg_end;

static const struct option long_options[] = {
{"help", no_argument, NULL, 'h' },
Expand All @@ -79,6 +81,8 @@ static const struct option long_options[] = {
{"txmsg_drop", no_argument, &txmsg_drop, 1 },
{"txmsg_apply", required_argument, NULL, 'a'},
{"txmsg_cork", required_argument, NULL, 'k'},
{"txmsg_start", required_argument, NULL, 's'},
{"txmsg_end", required_argument, NULL, 'e'},
{0, 0, NULL, 0 }
};

Expand Down Expand Up @@ -572,6 +576,12 @@ int main(int argc, char **argv)
while ((opt = getopt_long(argc, argv, ":dhvc:r:i:l:t:",
long_options, &longindex)) != -1) {
switch (opt) {
case 's':
txmsg_start = atoi(optarg);
break;
case 'e':
txmsg_end = atoi(optarg);
break;
case 'a':
txmsg_apply = atoi(optarg);
break;
Expand Down Expand Up @@ -761,6 +771,28 @@ int main(int argc, char **argv)
}
}

if (txmsg_start) {
err = bpf_map_update_elem(map_fd[5],
&i, &txmsg_start, BPF_ANY);
if (err) {
fprintf(stderr,
"ERROR: bpf_map_update_elem (txmsg_start): %d (%s)\n",
err, strerror(errno));
return err;
}
}

if (txmsg_end) {
i = 1;
err = bpf_map_update_elem(map_fd[5],
&i, &txmsg_end, BPF_ANY);
if (err) {
fprintf(stderr,
"ERROR: bpf_map_update_elem (txmsg_end): %d (%s)\n",
err, strerror(errno));
return err;
}
}
}

if (txmsg_drop)
Expand Down
3 changes: 2 additions & 1 deletion tools/include/uapi/linux/bpf.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -793,7 +793,8 @@ union bpf_attr {
FN(sock_ops_cb_flags_set), \
FN(msg_redirect_map), \
FN(msg_apply_bytes), \
FN(msg_cork_bytes),
FN(msg_cork_bytes), \
FN(msg_pull_data),

/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
Expand Down
2 changes: 2 additions & 0 deletions tools/testing/selftests/bpf/bpf_helpers.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -92,6 +92,8 @@ static int (*bpf_msg_apply_bytes)(void *ctx, int len) =
(void *) BPF_FUNC_msg_apply_bytes;
static int (*bpf_msg_cork_bytes)(void *ctx, int len) =
(void *) BPF_FUNC_msg_cork_bytes;
static int (*bpf_msg_pull_data)(void *ctx, int start, int end, int flags) =
(void *) BPF_FUNC_msg_pull_data;

/* llvm builtin functions that eBPF C program may use to
* emit BPF_LD_ABS and BPF_LD_IND instructions
Expand Down

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