From: Nathan Chancellor <nathan@kernel.org>
To: edumazet@google.com, davem@davemloft.net, dsahern@kernel.org,
kuba@kernel.org, pabeni@redhat.com
Cc: ndesaulniers@google.com, trix@redhat.com, 0x7f454c46@gmail.com,
noureddine@arista.com, hch@infradead.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
llvm@lists.linux.dev, patches@lists.linux.dev,
Nathan Chancellor <nathan@kernel.org>
Subject: [PATCH net v3] tcp: Fix -Wc23-extensions in tcp_options_write()
Date: Mon, 06 Nov 2023 14:14:16 -0700 [thread overview]
Message-ID: <20231106-tcp-ao-fix-label-in-compound-statement-warning-v3-1-b54a64602a85@kernel.org> (raw)
Clang warns (or errors with CONFIG_WERROR=y) when CONFIG_TCP_AO is set:
net/ipv4/tcp_output.c:663:2: error: label at end of compound statement is a C23 extension [-Werror,-Wc23-extensions]
663 | }
| ^
1 error generated.
On earlier releases (such as clang-11, the current minimum supported
version for building the kernel) that do not support C23, this was a
hard error unconditionally:
net/ipv4/tcp_output.c:663:2: error: expected statement
}
^
1 error generated.
While adding a semicolon after the label would resolve this, it is more
in line with the kernel as a whole to refactor this block into a
standalone function, which means the goto a label construct can just be
replaced with a return statement. Do so to resolve the warning.
Closes: https://github.com/ClangBuiltLinux/linux/issues/1953
Fixes: 1e03d32bea8e ("net/tcp: Add TCP-AO sign to outgoing packets")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
Changes in v3:
- Don't use a pointer to a pointer for ptr parameter to avoid the extra
indirection in process_tcp_ao_options(), just return the modified ptr
value back to the caller (Eric)
- Link to v2: https://lore.kernel.org/r/20231106-tcp-ao-fix-label-in-compound-statement-warning-v2-1-91eff6e1648c@kernel.org
Changes in v2:
- Break out problematic block into its own function so that goto can be
replaced with a simple return, instead of the simple semicolon
approach of v1 (Christoph)
- Link to v1: https://lore.kernel.org/r/20231031-tcp-ao-fix-label-in-compound-statement-warning-v1-1-c9731d115f17@kernel.org
---
net/ipv4/tcp_output.c | 70 ++++++++++++++++++++++++++++-----------------------
1 file changed, 39 insertions(+), 31 deletions(-)
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 0d8dd5b7e2e5..eb13a55d660c 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -601,6 +601,44 @@ static void bpf_skops_write_hdr_opt(struct sock *sk, struct sk_buff *skb,
}
#endif
+static __be32 *process_tcp_ao_options(struct tcp_sock *tp,
+ const struct tcp_request_sock *tcprsk,
+ struct tcp_out_options *opts,
+ struct tcp_key *key, __be32 *ptr)
+{
+#ifdef CONFIG_TCP_AO
+ u8 maclen = tcp_ao_maclen(key->ao_key);
+
+ if (tcprsk) {
+ u8 aolen = maclen + sizeof(struct tcp_ao_hdr);
+
+ *ptr++ = htonl((TCPOPT_AO << 24) | (aolen << 16) |
+ (tcprsk->ao_keyid << 8) |
+ (tcprsk->ao_rcv_next));
+ } else {
+ struct tcp_ao_key *rnext_key;
+ struct tcp_ao_info *ao_info;
+
+ ao_info = rcu_dereference_check(tp->ao_info,
+ lockdep_sock_is_held(&tp->inet_conn.icsk_inet.sk));
+ rnext_key = READ_ONCE(ao_info->rnext_key);
+ if (WARN_ON_ONCE(!rnext_key))
+ return ptr;
+ *ptr++ = htonl((TCPOPT_AO << 24) |
+ (tcp_ao_len(key->ao_key) << 16) |
+ (key->ao_key->sndid << 8) |
+ (rnext_key->rcvid));
+ }
+ opts->hash_location = (__u8 *)ptr;
+ ptr += maclen / sizeof(*ptr);
+ if (unlikely(maclen % sizeof(*ptr))) {
+ memset(ptr, TCPOPT_NOP, sizeof(*ptr));
+ ptr++;
+ }
+#endif
+ return ptr;
+}
+
/* Write previously computed TCP options to the packet.
*
* Beware: Something in the Internet is very sensitive to the ordering of
@@ -629,37 +667,7 @@ static void tcp_options_write(struct tcphdr *th, struct tcp_sock *tp,
opts->hash_location = (__u8 *)ptr;
ptr += 4;
} else if (tcp_key_is_ao(key)) {
-#ifdef CONFIG_TCP_AO
- u8 maclen = tcp_ao_maclen(key->ao_key);
-
- if (tcprsk) {
- u8 aolen = maclen + sizeof(struct tcp_ao_hdr);
-
- *ptr++ = htonl((TCPOPT_AO << 24) | (aolen << 16) |
- (tcprsk->ao_keyid << 8) |
- (tcprsk->ao_rcv_next));
- } else {
- struct tcp_ao_key *rnext_key;
- struct tcp_ao_info *ao_info;
-
- ao_info = rcu_dereference_check(tp->ao_info,
- lockdep_sock_is_held(&tp->inet_conn.icsk_inet.sk));
- rnext_key = READ_ONCE(ao_info->rnext_key);
- if (WARN_ON_ONCE(!rnext_key))
- goto out_ao;
- *ptr++ = htonl((TCPOPT_AO << 24) |
- (tcp_ao_len(key->ao_key) << 16) |
- (key->ao_key->sndid << 8) |
- (rnext_key->rcvid));
- }
- opts->hash_location = (__u8 *)ptr;
- ptr += maclen / sizeof(*ptr);
- if (unlikely(maclen % sizeof(*ptr))) {
- memset(ptr, TCPOPT_NOP, sizeof(*ptr));
- ptr++;
- }
-out_ao:
-#endif
+ ptr = process_tcp_ao_options(tp, tcprsk, opts, key, ptr);
}
if (unlikely(opts->mss)) {
*ptr++ = htonl((TCPOPT_MSS << 24) |
---
base-commit: c1ed833e0b3b7b9edc82b97b73b2a8a10ceab241
change-id: 20231031-tcp-ao-fix-label-in-compound-statement-warning-ebd6c9978498
Best regards,
--
Nathan Chancellor <nathan@kernel.org>
next reply other threads:[~2023-11-06 21:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-06 21:14 Nathan Chancellor [this message]
2023-11-06 21:26 ` [PATCH net v3] tcp: Fix -Wc23-extensions in tcp_options_write() Dmitry Safonov
2023-11-06 21:34 ` Nathan Chancellor
2023-11-06 21:48 ` Dmitry Safonov
2023-11-07 3:44 ` Eric Dumazet
2023-11-07 22:30 ` patchwork-bot+netdevbpf
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