diff mbox series

[net,3/6] net/diag: Pre-allocate optional info only if requested

Message ID 20241106-tcp-md5-diag-prep-v1-3-d62debf3dded@gmail.com (mailing list archive)
State Superseded, archived
Headers show
Series Make TCP-MD5-diag slightly less broken | expand

Checks

Context Check Description
matttbe/build success Build and static analysis OK
matttbe/checkpatch success total: 0 errors, 0 warnings, 0 checks, 42 lines checked
matttbe/shellcheck success MPTCP selftests files have not been modified
matttbe/KVM_Validation__normal success Success! ✅
matttbe/KVM_Validation__debug success Success! ✅
matttbe/KVM_Validation__btf-normal__only_bpftest_all_ success Success! ✅
matttbe/KVM_Validation__btf-debug__only_bpftest_all_ warning Unstable: 1 failed test(s): bpftest_test_progs_mptcp

Commit Message

Dmitry Safonov via B4 Relay Nov. 6, 2024, 6:10 p.m. UTC 
From: Dmitry Safonov <0x7f454c46@gmail.com>

Those INET_DIAG_* flags from req->idiag_ext are provided by the
userspace, so they are not going to change during one socket dump.
This is going to save just nits and bits for typical netlink reply,
which I'm going to utilise in the very next patch by always allocating
tls_get_info_size().
It's possible to save even some more by checking the request in
inet_diag_msg_attrs_size(), but that's being on very stingy side.

Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
---
 net/ipv4/inet_diag.c | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index ca9a7e61d8d7de80cb234c45c41d6357fde50c11..2dd173a73bd1e2657957e5e4ecb70401cc85dfda 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -102,24 +102,31 @@  static size_t inet_sk_attr_size(struct sock *sk,
 				bool net_admin)
 {
 	const struct inet_diag_handler *handler;
-	size_t aux = 0;
+	int ext = req->idiag_ext;
+	size_t ret = 0;
 
 	rcu_read_lock();
 	handler = rcu_dereference(inet_diag_table[req->sdiag_protocol]);
 	DEBUG_NET_WARN_ON_ONCE(!handler);
 	if (handler && handler->idiag_get_aux_size)
-		aux = handler->idiag_get_aux_size(sk, net_admin);
+		ret += handler->idiag_get_aux_size(sk, net_admin);
 	rcu_read_unlock();
 
-	return	  nla_total_size(sizeof(struct tcp_info))
-		+ nla_total_size(sizeof(struct inet_diag_msg))
-		+ inet_diag_msg_attrs_size()
-		+ nla_total_size(sizeof(struct inet_diag_meminfo))
-		+ nla_total_size(SK_MEMINFO_VARS * sizeof(u32))
-		+ nla_total_size(TCP_CA_NAME_MAX)
-		+ nla_total_size(sizeof(struct tcpvegas_info))
-		+ aux
-		+ 64;
+	ret += nla_total_size(sizeof(struct tcp_info))
+	     + nla_total_size(sizeof(struct inet_diag_msg))
+	     + inet_diag_msg_attrs_size()
+	     + 64;
+
+	if (ext & (1 << (INET_DIAG_MEMINFO - 1)))
+		ret += nla_total_size(sizeof(struct inet_diag_meminfo));
+	if (ext & (1 << (INET_DIAG_SKMEMINFO - 1)))
+		ret += nla_total_size(SK_MEMINFO_VARS * sizeof(u32));
+	if (ext & (1 << (INET_DIAG_CONG - 1)))
+		ret += nla_total_size(TCP_CA_NAME_MAX);
+	if (ext & (1 << (INET_DIAG_VEGASINFO - 1)))
+		ret += nla_total_size(sizeof(struct tcpvegas_info));
+
+	return ret;
 }
 
 int inet_diag_msg_attrs_fill(struct sock *sk, struct sk_buff *skb,