[PATCH net-next 05/10] net/tcp: Remove tcp_hash_fail()

Dmitry Safonov
2024-02-24T09:04:52Z

Now there are tracepoints, that cover all functionality of
tcp_hash_fail(), but also wire up missing places
They are also faster, can be disabled and provide filtering.

This potentially may create a regression if a userspace depends on dmesg
logs. Fingers crossed, let's see if anyone complains in reality.

Signed-off-by: Dmitry Safonov <dima@arista.com>
---
include/net/tcp_ao.h | 37 -------------------------------------
net/ipv4/tcp.c | 25 -------------------------
net/ipv4/tcp_ao.c | 9 ---------
3 files changed, 71 deletions(-)

diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h
index 6501ed1dfa1e..ebc6d4e3c073 100644
--- a/include/net/tcp_ao.h
+++ b/include/net/tcp_ao.h
@@ -148,43 +148,6 @@ extern struct static_key_false_deferred tcp_ao_needed;
#define static_branch_tcp_ao() false
#endif

-static inline bool tcp_hash_should_produce_warnings(void)
-{
- return static_branch_tcp_md5() || static_branch_tcp_ao();
-}
-
-#define tcp_hash_fail(msg, family, skb, fmt, ...) \
-do { \
- const struct tcphdr *th = tcp_hdr(skb); \
- char hdr_flags[6]; \
- char *f = hdr_flags; \
- \
- if (!tcp_hash_should_produce_warnings()) \
- break; \
- if (th->fin) \
- *f++ = 'F'; \
- if (th->syn) \
- *f++ = 'S'; \
- if (th->rst) \
- *f++ = 'R'; \
- if (th->psh) \
- *f++ = 'P'; \
- if (th->ack) \
- *f++ = '.'; \
- *f = 0; \
- if ((family) == AF_INET) { \
- net_info_ratelimited("%s for %pI4.%d->%pI4.%d [%s] " fmt "\n", \
- msg, &ip_hdr(skb)->saddr, ntohs(th->source), \
- &ip_hdr(skb)->daddr, ntohs(th->dest), \
- hdr_flags, ##__VA_ARGS__); \
- } else { \
- net_info_ratelimited("%s for [%pI6c].%d->[%pI6c].%d [%s]" fmt "\n", \
- msg, &ipv6_hdr(skb)->saddr, ntohs(th->source), \
- &ipv6_hdr(skb)->daddr, ntohs(th->dest), \
- hdr_flags, ##__VA_ARGS__); \
- } \
-} while (0)
-
#ifdef CONFIG_TCP_AO
/* TCP-AO structures and functions */
struct tcp4_ao_context {
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 81f22d6afe4a..e83fdce91554 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -4448,7 +4448,6 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb,

if (!key && hash_location) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
- tcp_hash_fail("Unexpected MD5 Hash found", family, skb, "");
trace_tcp_hash_md5_unexpected(sk, skb);
return SKB_DROP_REASON_TCP_MD5UNEXPECTED;
}
@@ -4464,21 +4463,6 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb,
NULL, skb);
if (genhash || memcmp(hash_location, newhash, 16) != 0) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
- if (family == AF_INET) {
- tcp_hash_fail("MD5 Hash failed", AF_INET, skb, "%s L3 index %d",
- genhash ? "tcp_v4_calc_md5_hash failed"
- : "", l3index);
- } else {
- if (genhash) {
- tcp_hash_fail("MD5 Hash failed",
- AF_INET6, skb, "L3 index %d",
- l3index);
- } else {
- tcp_hash_fail("MD5 Hash mismatch",
- AF_INET6, skb, "L3 index %d",
- l3index);
- }
- }
trace_tcp_hash_md5_mismatch(sk, skb);
return SKB_DROP_REASON_TCP_MD5FAILURE;
}
@@ -4502,8 +4486,6 @@ tcp_inbound_hash(struct sock *sk, const struct request_sock *req,

/* Invalid option or two times meet any of auth options */
if (tcp_parse_auth_options(th, &md5_location, &aoh)) {
- tcp_hash_fail("TCP segment has incorrect auth options set",
- family, skb, "");
trace_tcp_hash_bad_header(sk, skb);
return SKB_DROP_REASON_TCP_AUTH_HDR;
}
@@ -4521,9 +4503,6 @@ tcp_inbound_hash(struct sock *sk, const struct request_sock *req,
}

NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOBAD);
- tcp_hash_fail("TCP connection can't start/end using TCP-AO",
- family, skb, "%s",
- !aoh ? "missing AO" : "AO signed");
trace_tcp_ao_handshake_failure(sk, skb, keyid, rnext, maclen);
return SKB_DROP_REASON_TCP_AOFAILURE;
}
@@ -4542,15 +4521,11 @@ tcp_inbound_hash(struct sock *sk, const struct request_sock *req,
* always at least one current_key.
*/
if (tcp_ao_required(sk, saddr, family, l3index, true)) {
- tcp_hash_fail("AO hash is required, but not found",
- family, skb, "L3 index %d", l3index);
trace_tcp_hash_ao_required(sk, skb);
return SKB_DROP_REASON_TCP_AONOTFOUND;
}
if (unlikely(tcp_md5_do_lookup(sk, l3index, saddr, family))) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
- tcp_hash_fail("MD5 Hash not found",
- family, skb, "L3 index %d", l3index);
trace_tcp_hash_md5_required(sk, skb);
return SKB_DROP_REASON_TCP_MD5NOTFOUND;
}
diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c
index 416cdeaccd07..e99bf734d070 100644
--- a/net/ipv4/tcp_ao.c
+++ b/net/ipv4/tcp_ao.c
@@ -893,9 +893,6 @@ tcp_ao_verify_hash(const struct sock *sk, const struct sk_buff *skb,
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOBAD);
atomic64_inc(&info->counters.pkt_bad);
atomic64_inc(&key->pkt_bad);
- tcp_hash_fail("AO hash wrong length", family, skb,
- "%u != %d L3index: %d", maclen,
- tcp_ao_maclen(key), l3index);
trace_tcp_ao_wrong_maclen(sk, skb, aoh->keyid,
aoh->rnext_keyid, maclen);
return SKB_DROP_REASON_TCP_AOFAILURE;
@@ -912,8 +909,6 @@ tcp_ao_verify_hash(const struct sock *sk, const struct sk_buff *skb,
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOBAD);
atomic64_inc(&info->counters.pkt_bad);
atomic64_inc(&key->pkt_bad);
- tcp_hash_fail("AO hash mismatch", family, skb,
- "L3index: %d", l3index);
trace_tcp_ao_mismatch(sk, skb, aoh->keyid,
aoh->rnext_keyid, maclen);
kfree(hash_buf);
@@ -944,8 +939,6 @@ tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb,
info = rcu_dereference(tcp_sk(sk)->ao_info);
if (!info) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOKEYNOTFOUND);
- tcp_hash_fail("AO key not found", family, skb,
- "keyid: %u L3index: %d", aoh->keyid, l3index);
trace_tcp_ao_key_not_found(sk, skb, aoh->keyid,
aoh->rnext_keyid, maclen);
return SKB_DROP_REASON_TCP_AOUNEXPECTED;
@@ -1052,8 +1045,6 @@ tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb,
key_not_found:
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOKEYNOTFOUND);
atomic64_inc(&info->counters.key_not_found);
- tcp_hash_fail("Requested by the peer AO key id not found",
- family, skb, "L3index: %d", l3index);
trace_tcp_ao_key_not_found(sk, skb, aoh->keyid,
aoh->rnext_keyid, maclen);
return SKB_DROP_REASON_TCP_AOKEYNOTFOUND;

--
2.43.0