[bpf-next PATCH v3 17/18] bpf: sockmap sample test for bpf_msg_pull_data

John Fastabend
2018-03-18T19:58:16Z

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>
---
samples/sockmap/sockmap_kern.c | 79 ++++++++++++++++++++++++-----
samples/sockmap/sockmap_user.c | 32 ++++++++++++
tools/include/uapi/linux/bpf.h | 3 +
tools/testing/selftests/bpf/bpf_helpers.h | 2 +
4 files changed, 101 insertions(+), 15 deletions(-)

diff --git a/samples/sockmap/sockmap_kern.c b/samples/sockmap/sockmap_kern.c
index 8b6c34c..9ad5ba7 100644
--- a/samples/sockmap/sockmap_kern.c
+++ b/samples/sockmap/sockmap_kern.c
@@ -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)
{
@@ -137,7 +145,8 @@ 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)
@@ -145,15 +154,18 @@ int bpf_prog4(struct sk_msg_md *msg)
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)
@@ -161,17 +173,32 @@ int bpf_prog5(struct sk_msg_md *msg)
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)
@@ -179,15 +206,18 @@ int bpf_prog6(struct sk_msg_md *msg)
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)
@@ -195,9 +225,24 @@ int bpf_prog7(struct sk_msg_md *msg)
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);
}

@@ -239,7 +284,8 @@ 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)
@@ -247,6 +293,11 @@ int bpf_prog10(struct sk_msg_md *msg)
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;
}

diff --git a/samples/sockmap/sockmap_user.c b/samples/sockmap/sockmap_user.c
index 52c4ed7..07aa237 100644
--- a/samples/sockmap/sockmap_user.c
+++ b/samples/sockmap/sockmap_user.c
@@ -62,6 +62,8 @@
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' },
@@ -79,6 +81,8 @@
{"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 }
};

@@ -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;
@@ -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)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index e6924ab..d245c41 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -793,7 +793,8 @@ struct bpf_stack_build_id {
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
diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
index b5b45ff..7cae376 100644
--- a/tools/testing/selftests/bpf/bpf_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_helpers.h
@@ -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