Merge branch 'bpf-msg-push-data'

John Fastabend says:

====================
This series adds a new helper bpf_msg_push_data to be used by
sk_msg programs. The helper can be used to insert extra bytes into
the message that can then be used by the program as metadata tags
among other things.

The first patch adds the helper, second patch the libbpf support,
and last patch updates test_sockmap to run msg_push_data tests.

v2: rebase after queue map and in filter.c convert int -> u32
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

7 files changed, 308 insertions, 28 deletions

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 84e18863f6a4..2a11e9d91dfa 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -207,6 +207,11 @@ static inline struct scatterlist *sk_msg_elem(struct sk_msg *msg, int which)
 	return &msg->sg.data[which];
 }
 
+static inline struct scatterlist sk_msg_elem_cpy(struct sk_msg *msg, int which)
+{
+	return msg->sg.data[which];
+}
+
 static inline struct page *sk_msg_page(struct sk_msg *msg, int which)
 {
 	return sg_page(sk_msg_elem(msg, which));
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index a2fb333290dc..852dc17ab47a 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2240,6 +2240,23 @@ union bpf_attr {
  *		pointer that was returned from bpf_sk_lookup_xxx\ ().
  *	Return
  *		0 on success, or a negative error in case of failure.
+ *
+ * int bpf_msg_push_data(struct sk_buff *skb, u32 start, u32 len, u64 flags)
+ *	Description
+ *		For socket policies, insert *len* bytes into msg at offset
+ *		*start*.
+ *
+ *		If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
+ *		*msg* it may want to insert metadata or options into the msg.
+ *		This can later be read and used by any of the lower layer BPF
+ *		hooks.
+ *
+ *		This helper may fail if under memory pressure (a malloc
+ *		fails) in these cases BPF programs will get an appropriate
+ *		error and BPF programs will need to handle them.
+ *
+ *	Return
+ *		0 on success, or a negative error in case of failure.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -2331,7 +2348,8 @@ union bpf_attr {
 	FN(sk_release),			\
 	FN(map_push_elem),		\
 	FN(map_pop_elem),		\
-	FN(map_peek_elem),
+	FN(map_peek_elem),		\
+	FN(msg_push_data),
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
  * function eBPF program intends to call
diff --git a/net/core/filter.c b/net/core/filter.c
index 5fd5139e8638..35c6933c2622 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2297,6 +2297,137 @@ static const struct bpf_func_proto bpf_msg_pull_data_proto = {
 	.arg4_type	= ARG_ANYTHING,
 };
 
+BPF_CALL_4(bpf_msg_push_data, struct sk_msg *, msg, u32, start,
+	   u32, len, u64, flags)
+{
+	struct scatterlist sge, nsge, nnsge, rsge = {0}, *psge;
+	u32 new, i = 0, l, space, copy = 0, offset = 0;
+	u8 *raw, *to, *from;
+	struct page *page;
+
+	if (unlikely(flags))
+		return -EINVAL;
+
+	/* First find the starting scatterlist element */
+	i = msg->sg.start;
+	do {
+		l = sk_msg_elem(msg, i)->length;
+
+		if (start < offset + l)
+			break;
+		offset += l;
+		sk_msg_iter_var_next(i);
+	} while (i != msg->sg.end);
+
+	if (start >= offset + l)
+		return -EINVAL;
+
+	space = MAX_MSG_FRAGS - sk_msg_elem_used(msg);
+
+	/* If no space available will fallback to copy, we need at
+	 * least one scatterlist elem available to push data into
+	 * when start aligns to the beginning of an element or two
+	 * when it falls inside an element. We handle the start equals
+	 * offset case because its the common case for inserting a
+	 * header.
+	 */
+	if (!space || (space == 1 && start != offset))
+		copy = msg->sg.data[i].length;
+
+	page = alloc_pages(__GFP_NOWARN | GFP_ATOMIC | __GFP_COMP,
+			   get_order(copy + len));
+	if (unlikely(!page))
+		return -ENOMEM;
+
+	if (copy) {
+		int front, back;
+
+		raw = page_address(page);
+
+		psge = sk_msg_elem(msg, i);
+		front = start - offset;
+		back = psge->length - front;
+		from = sg_virt(psge);
+
+		if (front)
+			memcpy(raw, from, front);
+
+		if (back) {
+			from += front;
+			to = raw + front + len;
+
+			memcpy(to, from, back);
+		}
+
+		put_page(sg_page(psge));
+	} else if (start - offset) {
+		psge = sk_msg_elem(msg, i);
+		rsge = sk_msg_elem_cpy(msg, i);
+
+		psge->length = start - offset;
+		rsge.length -= psge->length;
+		rsge.offset += start;
+
+		sk_msg_iter_var_next(i);
+		sg_unmark_end(psge);
+		sk_msg_iter_next(msg, end);
+	}
+
+	/* Slot(s) to place newly allocated data */
+	new = i;
+
+	/* Shift one or two slots as needed */
+	if (!copy) {
+		sge = sk_msg_elem_cpy(msg, i);
+
+		sk_msg_iter_var_next(i);
+		sg_unmark_end(&sge);
+		sk_msg_iter_next(msg, end);
+
+		nsge = sk_msg_elem_cpy(msg, i);
+		if (rsge.length) {
+			sk_msg_iter_var_next(i);
+			nnsge = sk_msg_elem_cpy(msg, i);
+		}
+
+		while (i != msg->sg.end) {
+			msg->sg.data[i] = sge;
+			sge = nsge;
+			sk_msg_iter_var_next(i);
+			if (rsge.length) {
+				nsge = nnsge;
+				nnsge = sk_msg_elem_cpy(msg, i);
+			} else {
+				nsge = sk_msg_elem_cpy(msg, i);
+			}
+		}
+	}
+
+	/* Place newly allocated data buffer */
+	sk_mem_charge(msg->sk, len);
+	msg->sg.size += len;
+	msg->sg.copy[new] = false;
+	sg_set_page(&msg->sg.data[new], page, len + copy, 0);
+	if (rsge.length) {
+		get_page(sg_page(&rsge));
+		sk_msg_iter_var_next(new);
+		msg->sg.data[new] = rsge;
+	}
+
+	sk_msg_compute_data_pointers(msg);
+	return 0;
+}
+
+static const struct bpf_func_proto bpf_msg_push_data_proto = {
+	.func		= bpf_msg_push_data,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_ANYTHING,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_ANYTHING,
+};
+
 BPF_CALL_1(bpf_get_cgroup_classid, const struct sk_buff *, skb)
 {
 	return task_get_classid(skb);
@@ -4854,6 +4985,7 @@ bool bpf_helper_changes_pkt_data(void *func)
 	    func == bpf_xdp_adjust_head ||
 	    func == bpf_xdp_adjust_meta ||
 	    func == bpf_msg_pull_data ||
+	    func == bpf_msg_push_data ||
 	    func == bpf_xdp_adjust_tail ||
 #if IS_ENABLED(CONFIG_IPV6_SEG6_BPF)
 	    func == bpf_lwt_seg6_store_bytes ||
@@ -5130,6 +5262,8 @@ sk_msg_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_msg_cork_bytes_proto;
 	case BPF_FUNC_msg_pull_data:
 		return &bpf_msg_pull_data_proto;
+	case BPF_FUNC_msg_push_data:
+		return &bpf_msg_push_data_proto;
 	case BPF_FUNC_get_local_storage:
 		return &bpf_get_local_storage_proto;
 	default:
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index a2fb333290dc..852dc17ab47a 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -2240,6 +2240,23 @@ union bpf_attr {
  *		pointer that was returned from bpf_sk_lookup_xxx\ ().
  *	Return
  *		0 on success, or a negative error in case of failure.
+ *
+ * int bpf_msg_push_data(struct sk_buff *skb, u32 start, u32 len, u64 flags)
+ *	Description
+ *		For socket policies, insert *len* bytes into msg at offset
+ *		*start*.
+ *
+ *		If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
+ *		*msg* it may want to insert metadata or options into the msg.
+ *		This can later be read and used by any of the lower layer BPF
+ *		hooks.
+ *
+ *		This helper may fail if under memory pressure (a malloc
+ *		fails) in these cases BPF programs will get an appropriate
+ *		error and BPF programs will need to handle them.
+ *
+ *	Return
+ *		0 on success, or a negative error in case of failure.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -2331,7 +2348,8 @@ union bpf_attr {
 	FN(sk_release),			\
 	FN(map_push_elem),		\
 	FN(map_pop_elem),		\
-	FN(map_peek_elem),
+	FN(map_peek_elem),		\
+	FN(msg_push_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 6407a3df0f3b..686e57ce40f4 100644
--- a/tools/testing/selftests/bpf/bpf_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_helpers.h
@@ -111,6 +111,8 @@ 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;
+static int (*bpf_msg_push_data)(void *ctx, int start, int end, int flags) =
+	(void *) BPF_FUNC_msg_push_data;
 static int (*bpf_bind)(void *ctx, void *addr, int addr_len) =
 	(void *) BPF_FUNC_bind;
 static int (*bpf_xdp_adjust_tail)(void *ctx, int offset) =
diff --git a/tools/testing/selftests/bpf/test_sockmap.c b/tools/testing/selftests/bpf/test_sockmap.c
index cbd1c0be8680..622ade0a0957 100644
--- a/tools/testing/selftests/bpf/test_sockmap.c
+++ b/tools/testing/selftests/bpf/test_sockmap.c
@@ -77,6 +77,8 @@ int txmsg_apply;
 int txmsg_cork;
 int txmsg_start;
 int txmsg_end;
+int txmsg_start_push;
+int txmsg_end_push;
 int txmsg_ingress;
 int txmsg_skb;
 int ktls;
@@ -100,6 +102,8 @@ static const struct option long_options[] = {
 	{"txmsg_cork",	required_argument,	NULL, 'k'},
 	{"txmsg_start", required_argument,	NULL, 's'},
 	{"txmsg_end",	required_argument,	NULL, 'e'},
+	{"txmsg_start_push", required_argument,	NULL, 'p'},
+	{"txmsg_end_push",   required_argument,	NULL, 'q'},
 	{"txmsg_ingress", no_argument,		&txmsg_ingress, 1 },
 	{"txmsg_skb", no_argument,		&txmsg_skb, 1 },
 	{"ktls", no_argument,			&ktls, 1 },
@@ -903,6 +907,30 @@ run:
 			}
 		}
 
+		if (txmsg_start_push) {
+			i = 2;
+			err = bpf_map_update_elem(map_fd[5],
+						  &i, &txmsg_start_push, BPF_ANY);
+			if (err) {
+				fprintf(stderr,
+					"ERROR: bpf_map_update_elem (txmsg_start_push):  %d (%s)\n",
+					err, strerror(errno));
+				goto out;
+			}
+		}
+
+		if (txmsg_end_push) {
+			i = 3;
+			err = bpf_map_update_elem(map_fd[5],
+						  &i, &txmsg_end_push, BPF_ANY);
+			if (err) {
+				fprintf(stderr,
+					"ERROR: bpf_map_update_elem %i@%i (txmsg_end_push):  %d (%s)\n",
+					txmsg_end_push, i, err, strerror(errno));
+				goto out;
+			}
+		}
+
 		if (txmsg_ingress) {
 			int in = BPF_F_INGRESS;
 
@@ -1235,6 +1263,8 @@ static int test_mixed(int cgrp)
 	txmsg_pass = txmsg_noisy = txmsg_redir_noisy = txmsg_drop = 0;
 	txmsg_apply = txmsg_cork = 0;
 	txmsg_start = txmsg_end = 0;
+	txmsg_start_push = txmsg_end_push = 0;
+
 	/* Test small and large iov_count values with pass/redir/apply/cork */
 	txmsg_pass = 1;
 	txmsg_redir = 0;
@@ -1351,6 +1381,8 @@ static int test_start_end(int cgrp)
 	/* Test basic start/end with lots of iov_count and iov_lengths */
 	txmsg_start = 1;
 	txmsg_end = 2;
+	txmsg_start_push = 1;
+	txmsg_end_push = 2;
 	err = test_txmsg(cgrp);
 	if (err)
 		goto out;
@@ -1364,6 +1396,8 @@ static int test_start_end(int cgrp)
 	for (i = 99; i <= 1600; i += 500) {
 		txmsg_start = 0;
 		txmsg_end = i;
+		txmsg_start_push = 0;
+		txmsg_end_push = i;
 		err = test_exec(cgrp, &opt);
 		if (err)
 			goto out;
@@ -1373,6 +1407,8 @@ static int test_start_end(int cgrp)
 	for (i = 199; i <= 1600; i += 500) {
 		txmsg_start = 100;
 		txmsg_end = i;
+		txmsg_start_push = 100;
+		txmsg_end_push = i;
 		err = test_exec(cgrp, &opt);
 		if (err)
 			goto out;
@@ -1381,6 +1417,8 @@ static int test_start_end(int cgrp)
 	/* Test start/end with cork pulling last sg entry */
 	txmsg_start = 1500;
 	txmsg_end = 1600;
+	txmsg_start_push = 1500;
+	txmsg_end_push = 1600;
 	err = test_exec(cgrp, &opt);
 	if (err)
 		goto out;
@@ -1388,6 +1426,8 @@ static int test_start_end(int cgrp)
 	/* Test start/end pull of single byte in last page */
 	txmsg_start = 1111;
 	txmsg_end = 1112;
+	txmsg_start_push = 1111;
+	txmsg_end_push = 1112;
 	err = test_exec(cgrp, &opt);
 	if (err)
 		goto out;
@@ -1395,6 +1435,8 @@ static int test_start_end(int cgrp)
 	/* Test start/end with end < start */
 	txmsg_start = 1111;
 	txmsg_end = 0;
+	txmsg_start_push = 1111;
+	txmsg_end_push = 0;
 	err = test_exec(cgrp, &opt);
 	if (err)
 		goto out;
@@ -1402,6 +1444,8 @@ static int test_start_end(int cgrp)
 	/* Test start/end with end > data */
 	txmsg_start = 0;
 	txmsg_end = 1601;
+	txmsg_start_push = 0;
+	txmsg_end_push = 1601;
 	err = test_exec(cgrp, &opt);
 	if (err)
 		goto out;
@@ -1409,6 +1453,8 @@ static int test_start_end(int cgrp)
 	/* Test start/end with start > data */
 	txmsg_start = 1601;
 	txmsg_end = 1600;
+	txmsg_start_push = 1601;
+	txmsg_end_push = 1600;
 	err = test_exec(cgrp, &opt);
 
 out:
@@ -1424,7 +1470,7 @@ char *map_names[] = {
 	"sock_map_redir",
 	"sock_apply_bytes",
 	"sock_cork_bytes",
-	"sock_pull_bytes",
+	"sock_bytes",
 	"sock_redir_flags",
 	"sock_skb_opts",
 };
@@ -1531,7 +1577,7 @@ static int __test_suite(int cg_fd, char *bpf_file)
 	}
 
 	/* Tests basic commands and APIs with range of iov values */
-	txmsg_start = txmsg_end = 0;
+	txmsg_start = txmsg_end = txmsg_start_push = txmsg_end_push = 0;
 	err = test_txmsg(cg_fd);
 	if (err)
 		goto out;
@@ -1580,7 +1626,7 @@ int main(int argc, char **argv)
 	if (argc < 2)
 		return test_suite(-1);
 
-	while ((opt = getopt_long(argc, argv, ":dhvc:r:i:l:t:",
+	while ((opt = getopt_long(argc, argv, ":dhvc:r:i:l:t:p:q:",
 				  long_options, &longindex)) != -1) {
 		switch (opt) {
 		case 's':
@@ -1589,6 +1635,12 @@ int main(int argc, char **argv)
 		case 'e':
 			txmsg_end = atoi(optarg);
 			break;
+		case 'p':
+			txmsg_start_push = atoi(optarg);
+			break;
+		case 'q':
+			txmsg_end_push = atoi(optarg);
+			break;
 		case 'a':
 			txmsg_apply = atoi(optarg);
 			break;
diff --git a/tools/testing/selftests/bpf/test_sockmap_kern.h b/tools/testing/selftests/bpf/test_sockmap_kern.h
index 8e8e41780bb9..14b8bbac004f 100644
--- a/tools/testing/selftests/bpf/test_sockmap_kern.h
+++ b/tools/testing/selftests/bpf/test_sockmap_kern.h
@@ -70,11 +70,11 @@ struct bpf_map_def SEC("maps") sock_cork_bytes = {
 	.max_entries = 1
 };
 
-struct bpf_map_def SEC("maps") sock_pull_bytes = {
+struct bpf_map_def SEC("maps") sock_bytes = {
 	.type = BPF_MAP_TYPE_ARRAY,
 	.key_size = sizeof(int),
 	.value_size = sizeof(int),
-	.max_entries = 2
+	.max_entries = 4
 };
 
 struct bpf_map_def SEC("maps") sock_redir_flags = {
@@ -181,8 +181,8 @@ int bpf_sockmap(struct bpf_sock_ops *skops)
 SEC("sk_msg1")
 int bpf_prog4(struct sk_msg_md *msg)
 {
-	int *bytes, zero = 0, one = 1;
-	int *start, *end;
+	int *bytes, zero = 0, one = 1, two = 2, three = 3;
+	int *start, *end, *start_push, *end_push;
 
 	bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero);
 	if (bytes)
@@ -190,18 +190,24 @@ 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);
+	start = bpf_map_lookup_elem(&sock_bytes, &zero);
+	end = bpf_map_lookup_elem(&sock_bytes, &one);
 	if (start && end)
 		bpf_msg_pull_data(msg, *start, *end, 0);
+	start_push = bpf_map_lookup_elem(&sock_bytes, &two);
+	end_push = bpf_map_lookup_elem(&sock_bytes, &three);
+	if (start_push && end_push)
+		bpf_msg_push_data(msg, *start_push, *end_push, 0);
 	return SK_PASS;
 }
 
 SEC("sk_msg2")
 int bpf_prog5(struct sk_msg_md *msg)
 {
-	int err1 = -1, err2 = -1, zero = 0, one = 1;
-	int *bytes, *start, *end, len1, len2;
+	int zero = 0, one = 1, two = 2, three = 3;
+	int *start, *end, *start_push, *end_push;
+	int *bytes, len1, len2 = 0, len3;
+	int err1 = -1, err2 = -1;
 
 	bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero);
 	if (bytes)
@@ -210,8 +216,8 @@ int bpf_prog5(struct sk_msg_md *msg)
 	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);
+	start = bpf_map_lookup_elem(&sock_bytes, &zero);
+	end = bpf_map_lookup_elem(&sock_bytes, &one);
 	if (start && end) {
 		int err;
 
@@ -225,6 +231,23 @@ int bpf_prog5(struct sk_msg_md *msg)
 		bpf_printk("sk_msg2: length update %i->%i\n",
 			   len1, len2);
 	}
+
+	start_push = bpf_map_lookup_elem(&sock_bytes, &two);
+	end_push = bpf_map_lookup_elem(&sock_bytes, &three);
+	if (start_push && end_push) {
+		int err;
+
+		bpf_printk("sk_msg2: push(%i:%i)\n",
+			   start_push ? *start_push : 0,
+			   end_push ? *end_push : 0);
+		err = bpf_msg_push_data(msg, *start_push, *end_push, 0);
+		if (err)
+			bpf_printk("sk_msg2: push_data err %i\n", err);
+		len3 = (__u64)msg->data_end - (__u64)msg->data;
+		bpf_printk("sk_msg2: length push_update %i->%i\n",
+			   len2 ? len2 : len1, len3);
+	}
+
 	bpf_printk("sk_msg2: data length %i err1 %i err2 %i\n",
 		   len1, err1, err2);
 	return SK_PASS;
@@ -233,8 +256,8 @@ int bpf_prog5(struct sk_msg_md *msg)
 SEC("sk_msg3")
 int bpf_prog6(struct sk_msg_md *msg)
 {
-	int *bytes, zero = 0, one = 1, key = 0;
-	int *start, *end, *f;
+	int *bytes, *start, *end, *start_push, *end_push, *f;
+	int zero = 0, one = 1, two = 2, three = 3, key = 0;
 	__u64 flags = 0;
 
 	bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero);
@@ -243,10 +266,17 @@ 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);
+
+	start = bpf_map_lookup_elem(&sock_bytes, &zero);
+	end = bpf_map_lookup_elem(&sock_bytes, &one);
 	if (start && end)
 		bpf_msg_pull_data(msg, *start, *end, 0);
+
+	start_push = bpf_map_lookup_elem(&sock_bytes, &two);
+	end_push = bpf_map_lookup_elem(&sock_bytes, &three);
+	if (start_push && end_push)
+		bpf_msg_push_data(msg, *start_push, *end_push, 0);
+
 	f = bpf_map_lookup_elem(&sock_redir_flags, &zero);
 	if (f && *f) {
 		key = 2;
@@ -262,8 +292,9 @@ int bpf_prog6(struct sk_msg_md *msg)
 SEC("sk_msg4")
 int bpf_prog7(struct sk_msg_md *msg)
 {
-	int err1 = 0, err2 = 0, zero = 0, one = 1, key = 0;
-	int *f, *bytes, *start, *end, len1, len2;
+	int zero = 0, one = 1, two = 2, three = 3, len1, len2 = 0, len3;
+	int *bytes, *start, *end, *start_push, *end_push, *f;
+	int err1 = 0, err2 = 0, key = 0;
 	__u64 flags = 0;
 
 		int err;
@@ -274,10 +305,10 @@ int bpf_prog7(struct sk_msg_md *msg)
 	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) {
 
+	start = bpf_map_lookup_elem(&sock_bytes, &zero);
+	end = bpf_map_lookup_elem(&sock_bytes, &one);
+	if (start && end) {
 		bpf_printk("sk_msg2: pull(%i:%i)\n",
 			   start ? *start : 0, end ? *end : 0);
 		err = bpf_msg_pull_data(msg, *start, *end, 0);
@@ -288,6 +319,22 @@ int bpf_prog7(struct sk_msg_md *msg)
 		bpf_printk("sk_msg2: length update %i->%i\n",
 			   len1, len2);
 	}
+
+	start_push = bpf_map_lookup_elem(&sock_bytes, &two);
+	end_push = bpf_map_lookup_elem(&sock_bytes, &three);
+	if (start_push && end_push) {
+		bpf_printk("sk_msg4: push(%i:%i)\n",
+			   start_push ? *start_push : 0,
+			   end_push ? *end_push : 0);
+		err = bpf_msg_push_data(msg, *start_push, *end_push, 0);
+		if (err)
+			bpf_printk("sk_msg4: push_data err %i\n",
+				   err);
+		len3 = (__u64)msg->data_end - (__u64)msg->data;
+		bpf_printk("sk_msg4: length push_update %i->%i\n",
+			   len2 ? len2 : len1, len3);
+	}
+
 	f = bpf_map_lookup_elem(&sock_redir_flags, &zero);
 	if (f && *f) {
 		key = 2;
@@ -342,8 +389,8 @@ int bpf_prog9(struct sk_msg_md *msg)
 SEC("sk_msg7")
 int bpf_prog10(struct sk_msg_md *msg)
 {
-	int *bytes, zero = 0, one = 1;
-	int *start, *end;
+	int *bytes, *start, *end, *start_push, *end_push;
+	int zero = 0, one = 1, two = 2, three = 3;
 
 	bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero);
 	if (bytes)
@@ -351,10 +398,14 @@ 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);
+	start = bpf_map_lookup_elem(&sock_bytes, &zero);
+	end = bpf_map_lookup_elem(&sock_bytes, &one);
 	if (start && end)
 		bpf_msg_pull_data(msg, *start, *end, 0);
+	start_push = bpf_map_lookup_elem(&sock_bytes, &two);
+	end_push = bpf_map_lookup_elem(&sock_bytes, &three);
+	if (start_push && end_push)
+		bpf_msg_push_data(msg, *start_push, *end_push, 0);
 
 	return SK_DROP;
 }