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tcp: Fix -Wc23-extensions in tcp_options_write()

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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: 1e03d32bea ("net/tcp: Add TCP-AO sign to outgoing packets")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Dmitry Safonov <dima@arista.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Nathan Chancellor 2023-11-06 14:14:16 -07:00 committed by David S. Miller
parent c542b39b60
commit 7425627b2b
1 changed files with 39 additions and 31 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

70
net/ipv4/tcp_output.c
View file

@ -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) |