bpf: sockmap sample test for bpf_msg_pull_data

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>

2 files changed, 97 insertions, 14 deletions

diff --git a/samples/sockmap/sockmap_kern.c b/samples/sockmap/sockmap_kern.c
index 8b6c34cd5f46..9ad5ba79c85a 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 52c4ed7774d4..07aa237221d1 100644
--- a/samples/sockmap/sockmap_user.c
+++ b/samples/sockmap/sockmap_user.c
@@ -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' },
@@ -79,6 +81,8 @@ static const struct option long_options[] = {
         {"txmsg_drop",          no_argument,    &txmsg_drop, 1 },