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net/tcp: Add tcp-md5 and tcp-ao tracepoints

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Instead of forcing userspace to parse dmesg (that's what currently is
happening, at least in codebase of my current company), provide a better
way, that can be enabled/disabled in runtime.

Currently, there are already tcp events, add hashing related ones there,
too. Rasdaemon currently exercises net_dev_xmit_timeout,
devlink_health_report, but it'll be trivial to teach it to deal with
failed hashes. Otherwise, BGP may trace/log them itself. Especially
exciting for possible investigations is key rotation (RNext_key
requests).

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Dmitry Safonov 2024-06-07 00:25:58 +01:00 committed by David S. Miller
parent 811efc06e5
commit 96be3dcd01
5 changed files with 355 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

317
include/trace/events/tcp.h
View File

@ -411,6 +411,323 @@ TRACE_EVENT(tcp_cong_state_set,
__entry->cong_state)
);
DECLARE_EVENT_CLASS(tcp_hash_event,
TP_PROTO(const struct sock *sk, const struct sk_buff *skb),
TP_ARGS(sk, skb),
TP_STRUCT__entry(
__field(__u64, net_cookie)
__field(const void *, skbaddr)
__field(const void *, skaddr)
__field(int, state)
/* sockaddr_in6 is always bigger than sockaddr_in */
__array(__u8, saddr, sizeof(struct sockaddr_in6))
__array(__u8, daddr, sizeof(struct sockaddr_in6))
__field(int, l3index)
__field(__u16, sport)
__field(__u16, dport)
__field(__u16, family)
__field(bool, fin)
__field(bool, syn)
__field(bool, rst)
__field(bool, psh)
__field(bool, ack)
),
TP_fast_assign(
const struct tcphdr *th = (const struct tcphdr *)skb->data;
__entry->net_cookie = sock_net(sk)->net_cookie;
__entry->skbaddr = skb;
__entry->skaddr = sk;
__entry->state = sk->sk_state;
memset(__entry->saddr, 0, sizeof(struct sockaddr_in6));
memset(__entry->daddr, 0, sizeof(struct sockaddr_in6));
TP_STORE_ADDR_PORTS_SKB(skb, th, __entry->saddr, __entry->daddr);
__entry->l3index = inet_sdif(skb) ? inet_iif(skb) : 0;
/* For filtering use */
__entry->sport = ntohs(th->source);
__entry->dport = ntohs(th->dest);
__entry->family = sk->sk_family;
__entry->fin = th->fin;
__entry->syn = th->syn;
__entry->rst = th->rst;
__entry->psh = th->psh;
__entry->ack = th->ack;
),
TP_printk("net=%llu state=%s family=%s src=%pISpc dest=%pISpc L3index=%d [%c%c%c%c%c]",
__entry->net_cookie,
show_tcp_state_name(__entry->state),
show_family_name(__entry->family),
__entry->saddr, __entry->daddr,
__entry->l3index,
__entry->fin ? 'F' : ' ',
__entry->syn ? 'S' : ' ',
__entry->rst ? 'R' : ' ',
__entry->psh ? 'P' : ' ',
__entry->ack ? '.' : ' ')
);
DEFINE_EVENT(tcp_hash_event, tcp_hash_bad_header,
TP_PROTO(const struct sock *sk, const struct sk_buff *skb),
TP_ARGS(sk, skb)
);
DEFINE_EVENT(tcp_hash_event, tcp_hash_md5_required,
TP_PROTO(const struct sock *sk, const struct sk_buff *skb),
TP_ARGS(sk, skb)
);
DEFINE_EVENT(tcp_hash_event, tcp_hash_md5_unexpected,
TP_PROTO(const struct sock *sk, const struct sk_buff *skb),
TP_ARGS(sk, skb)
);
DEFINE_EVENT(tcp_hash_event, tcp_hash_md5_mismatch,
TP_PROTO(const struct sock *sk, const struct sk_buff *skb),
TP_ARGS(sk, skb)
);
DEFINE_EVENT(tcp_hash_event, tcp_hash_ao_required,
TP_PROTO(const struct sock *sk, const struct sk_buff *skb),
TP_ARGS(sk, skb)
);
DECLARE_EVENT_CLASS(tcp_ao_event,
TP_PROTO(const struct sock *sk, const struct sk_buff *skb,
const __u8 keyid, const __u8 rnext, const __u8 maclen),
TP_ARGS(sk, skb, keyid, rnext, maclen),
TP_STRUCT__entry(
__field(__u64, net_cookie)
__field(const void *, skbaddr)
__field(const void *, skaddr)
__field(int, state)
/* sockaddr_in6 is always bigger than sockaddr_in */
__array(__u8, saddr, sizeof(struct sockaddr_in6))
__array(__u8, daddr, sizeof(struct sockaddr_in6))
__field(int, l3index)
__field(__u16, sport)
__field(__u16, dport)
__field(__u16, family)
__field(bool, fin)
__field(bool, syn)
__field(bool, rst)
__field(bool, psh)
__field(bool, ack)
__field(__u8, keyid)
__field(__u8, rnext)
__field(__u8, maclen)
),
TP_fast_assign(
const struct tcphdr *th = (const struct tcphdr *)skb->data;
__entry->net_cookie = sock_net(sk)->net_cookie;
__entry->skbaddr = skb;
__entry->skaddr = sk;
__entry->state = sk->sk_state;
memset(__entry->saddr, 0, sizeof(struct sockaddr_in6));
memset(__entry->daddr, 0, sizeof(struct sockaddr_in6));
TP_STORE_ADDR_PORTS_SKB(skb, th, __entry->saddr, __entry->daddr);
__entry->l3index = inet_sdif(skb) ? inet_iif(skb) : 0;
/* For filtering use */
__entry->sport = ntohs(th->source);
__entry->dport = ntohs(th->dest);
__entry->family = sk->sk_family;
__entry->fin = th->fin;
__entry->syn = th->syn;
__entry->rst = th->rst;
__entry->psh = th->psh;
__entry->ack = th->ack;
__entry->keyid = keyid;
__entry->rnext = rnext;
__entry->maclen = maclen;
),
TP_printk("net=%llu state=%s family=%s src=%pISpc dest=%pISpc L3index=%d [%c%c%c%c%c] keyid=%u rnext=%u maclen=%u",
__entry->net_cookie,
show_tcp_state_name(__entry->state),
show_family_name(__entry->family),
__entry->saddr, __entry->daddr,
__entry->l3index,
__entry->fin ? 'F' : ' ',
__entry->syn ? 'S' : ' ',
__entry->rst ? 'R' : ' ',
__entry->psh ? 'P' : ' ',
__entry->ack ? '.' : ' ',
__entry->keyid, __entry->rnext, __entry->maclen)
);
DEFINE_EVENT(tcp_ao_event, tcp_ao_handshake_failure,
TP_PROTO(const struct sock *sk, const struct sk_buff *skb,
const __u8 keyid, const __u8 rnext, const __u8 maclen),
TP_ARGS(sk, skb, keyid, rnext, maclen)
);
DEFINE_EVENT(tcp_ao_event, tcp_ao_wrong_maclen,
TP_PROTO(const struct sock *sk, const struct sk_buff *skb,
const __u8 keyid, const __u8 rnext, const __u8 maclen),
TP_ARGS(sk, skb, keyid, rnext, maclen)
);
DEFINE_EVENT(tcp_ao_event, tcp_ao_mismatch,
TP_PROTO(const struct sock *sk, const struct sk_buff *skb,
const __u8 keyid, const __u8 rnext, const __u8 maclen),
TP_ARGS(sk, skb, keyid, rnext, maclen)
);
DEFINE_EVENT(tcp_ao_event, tcp_ao_key_not_found,
TP_PROTO(const struct sock *sk, const struct sk_buff *skb,
const __u8 keyid, const __u8 rnext, const __u8 maclen),
TP_ARGS(sk, skb, keyid, rnext, maclen)
);
DEFINE_EVENT(tcp_ao_event, tcp_ao_rnext_request,
TP_PROTO(const struct sock *sk, const struct sk_buff *skb,
const __u8 keyid, const __u8 rnext, const __u8 maclen),
TP_ARGS(sk, skb, keyid, rnext, maclen)
);
DECLARE_EVENT_CLASS(tcp_ao_event_sk,
TP_PROTO(const struct sock *sk, const __u8 keyid, const __u8 rnext),
TP_ARGS(sk, keyid, rnext),
TP_STRUCT__entry(
__field(__u64, net_cookie)
__field(const void *, skaddr)
__field(int, state)
/* sockaddr_in6 is always bigger than sockaddr_in */
__array(__u8, saddr, sizeof(struct sockaddr_in6))
__array(__u8, daddr, sizeof(struct sockaddr_in6))
__field(__u16, sport)
__field(__u16, dport)
__field(__u16, family)
__field(__u8, keyid)
__field(__u8, rnext)
),
TP_fast_assign(
const struct inet_sock *inet = inet_sk(sk);
__entry->net_cookie = sock_net(sk)->net_cookie;
__entry->skaddr = sk;
__entry->state = sk->sk_state;
memset(__entry->saddr, 0, sizeof(struct sockaddr_in6));
memset(__entry->daddr, 0, sizeof(struct sockaddr_in6));
TP_STORE_ADDR_PORTS(__entry, inet, sk);
/* For filtering use */
__entry->sport = ntohs(inet->inet_sport);
__entry->dport = ntohs(inet->inet_dport);
__entry->family = sk->sk_family;
__entry->keyid = keyid;
__entry->rnext = rnext;
),
TP_printk("net=%llu state=%s family=%s src=%pISpc dest=%pISpc keyid=%u rnext=%u",
__entry->net_cookie,
show_tcp_state_name(__entry->state),
show_family_name(__entry->family),
__entry->saddr, __entry->daddr,
__entry->keyid, __entry->rnext)
);
DEFINE_EVENT(tcp_ao_event_sk, tcp_ao_synack_no_key,
TP_PROTO(const struct sock *sk, const __u8 keyid, const __u8 rnext),
TP_ARGS(sk, keyid, rnext)
);
DECLARE_EVENT_CLASS(tcp_ao_event_sne,
TP_PROTO(const struct sock *sk, __u32 new_sne),
TP_ARGS(sk, new_sne),
TP_STRUCT__entry(
__field(__u64, net_cookie)
__field(const void *, skaddr)
__field(int, state)
/* sockaddr_in6 is always bigger than sockaddr_in */
__array(__u8, saddr, sizeof(struct sockaddr_in6))
__array(__u8, daddr, sizeof(struct sockaddr_in6))
__field(__u16, sport)
__field(__u16, dport)
__field(__u16, family)
__field(__u32, new_sne)
),
TP_fast_assign(
const struct inet_sock *inet = inet_sk(sk);
__entry->net_cookie = sock_net(sk)->net_cookie;
__entry->skaddr = sk;
__entry->state = sk->sk_state;
memset(__entry->saddr, 0, sizeof(struct sockaddr_in6));
memset(__entry->daddr, 0, sizeof(struct sockaddr_in6));
TP_STORE_ADDR_PORTS(__entry, inet, sk);
/* For filtering use */
__entry->sport = ntohs(inet->inet_sport);
__entry->dport = ntohs(inet->inet_dport);
__entry->family = sk->sk_family;
__entry->new_sne = new_sne;
),
TP_printk("net=%llu state=%s family=%s src=%pISpc dest=%pISpc sne=%u",
__entry->net_cookie,
show_tcp_state_name(__entry->state),
show_family_name(__entry->family),
__entry->saddr, __entry->daddr,
__entry->new_sne)
);
DEFINE_EVENT(tcp_ao_event_sne, tcp_ao_snd_sne_update,
TP_PROTO(const struct sock *sk, __u32 new_sne),
TP_ARGS(sk, new_sne)
);
DEFINE_EVENT(tcp_ao_event_sne, tcp_ao_rcv_sne_update,
TP_PROTO(const struct sock *sk, __u32 new_sne),
TP_ARGS(sk, new_sne)
);
#endif /* _TRACE_TCP_H */
/* This part must be outside protection */

17
net/ipv4/tcp.c
View File

@ -282,6 +282,7 @@
#include <asm/ioctls.h>
#include <net/busy_poll.h>
#include <net/hotdata.h>
#include <trace/events/tcp.h>
#include <net/rps.h>
/* Track pending CMSGs. */
@ -4484,6 +4485,7 @@ 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;
}
@ -4513,6 +4515,7 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb,
l3index);
}
}
trace_tcp_hash_md5_mismatch(sk, skb);
return SKB_DROP_REASON_TCP_MD5FAILURE;
}
return SKB_NOT_DROPPED_YET;
@ -4544,15 +4547,27 @@ tcp_inbound_hash(struct sock *sk, const struct request_sock *req,
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;
}
if (req) {
if (tcp_rsk_used_ao(req) != !!aoh) {
u8 keyid, rnext, maclen;
if (aoh) {
keyid = aoh->keyid;
rnext = aoh->rnext_keyid;
maclen = tcp_ao_hdr_maclen(aoh);
} else {
keyid = rnext = maclen = 0;
}
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;
}
}
@ -4572,12 +4587,14 @@ tcp_inbound_hash(struct sock *sk, const struct request_sock *req,
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;
}
return SKB_NOT_DROPPED_YET;

13
net/ipv4/tcp_ao.c
View File

@ -16,6 +16,7 @@
#include <net/tcp.h>
#include <net/ipv6.h>
#include <net/icmp.h>
#include <trace/events/tcp.h>
DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_ao_needed, HZ);
@ -895,6 +896,8 @@ tcp_ao_verify_hash(const struct sock *sk, const struct sk_buff *skb,
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;
}
@ -911,6 +914,8 @@ tcp_ao_verify_hash(const struct sock *sk, const struct sk_buff *skb,
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);
return SKB_DROP_REASON_TCP_AOFAILURE;
}
@ -927,6 +932,7 @@ tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb,
int l3index, const struct tcp_ao_hdr *aoh)
{
const struct tcphdr *th = tcp_hdr(skb);
u8 maclen = tcp_ao_hdr_maclen(aoh);
u8 *phash = (u8 *)(aoh + 1); /* hash goes just after the header */
struct tcp_ao_info *info;
enum skb_drop_reason ret;
@ -941,6 +947,8 @@ tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb,
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;
}
@ -981,6 +989,9 @@ tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb,
current_key = READ_ONCE(info->current_key);
/* Key rotation: the peer asks us to use new key (RNext) */
if (unlikely(aoh->rnext_keyid != current_key->sndid)) {
trace_tcp_ao_rnext_request(sk, skb, current_key->sndid,
aoh->rnext_keyid,
tcp_ao_hdr_maclen(aoh));
/* If the key is not found we do nothing. */
key = tcp_ao_established_key(info, aoh->rnext_keyid, -1);
if (key)
@ -1048,6 +1059,8 @@ key_not_found:
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;
}

8
net/ipv4/tcp_input.c
View File

@ -3578,8 +3578,10 @@ static void tcp_snd_sne_update(struct tcp_sock *tp, u32 ack)
ao = rcu_dereference_protected(tp->ao_info,
lockdep_sock_is_held((struct sock *)tp));
if (ao && ack < tp->snd_una)
if (ao && ack < tp->snd_una) {
ao->snd_sne++;
trace_tcp_ao_snd_sne_update((struct sock *)tp, ao->snd_sne);
}
#endif
}
@ -3604,8 +3606,10 @@ static void tcp_rcv_sne_update(struct tcp_sock *tp, u32 seq)
ao = rcu_dereference_protected(tp->ao_info,
lockdep_sock_is_held((struct sock *)tp));
if (ao && seq < tp->rcv_nxt)
if (ao && seq < tp->rcv_nxt) {
ao->rcv_sne++;
trace_tcp_ao_rcv_sne_update((struct sock *)tp, ao->rcv_sne);
}
#endif
}

2
net/ipv4/tcp_output.c
View File

@ -3768,6 +3768,7 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
#ifdef CONFIG_TCP_AO
struct tcp_ao_key *ao_key = NULL;
u8 keyid = tcp_rsk(req)->ao_keyid;
u8 rnext = tcp_rsk(req)->ao_rcv_next;
ao_key = tcp_sk(sk)->af_specific->ao_lookup(sk, req_to_sk(req),
keyid, -1);
@ -3777,6 +3778,7 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
* ao_keyid (RFC5925 RNextKeyID), so let's keep it simple here.
*/
if (unlikely(!ao_key)) {
trace_tcp_ao_synack_no_key(sk, keyid, rnext);
rcu_read_unlock();
kfree_skb(skb);
net_warn_ratelimited("TCP-AO: the keyid %u from SYN packet is not present - not sending SYNACK\n",