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authorJakub Kicinski <kuba@kernel.org>2021-05-14 23:04:25 +0300
committerDavid S. Miller <davem@davemloft.net>2021-05-15 01:26:03 +0300
commit709c0314239992162cba26a860f04319a15860c4 (patch)
tree0a773304deb90df6e99174cff10593912f151830 /net
parent7466b60a3c32a8ad8033b06089e5aae5e8260e86 (diff)
downloadlinux-709c0314239992162cba26a860f04319a15860c4.tar.xz
tcp: add tracepoint for checksum errors
Add a tracepoint for capturing TCP segments with a bad checksum. This makes it easy to identify sources of bad frames in the fleet (e.g. machines with faulty NICs). It should also help tools like IOvisor's tcpdrop.py which are used today to get detailed information about such packets. We don't have a socket in many cases so we must open code the address extraction based just on the skb. v2: add missing export for ipv6=m Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/net-traces.c1
-rw-r--r--net/ipv4/tcp_input.c1
-rw-r--r--net/ipv4/tcp_ipv4.c3
-rw-r--r--net/ipv6/tcp_ipv6.c2
4 files changed, 7 insertions, 0 deletions
diff --git a/net/core/net-traces.c b/net/core/net-traces.c
index 283ddb2dbc7d..c40cd8dd75c7 100644
--- a/net/core/net-traces.c
+++ b/net/core/net-traces.c
@@ -60,3 +60,4 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(kfree_skb);
EXPORT_TRACEPOINT_SYMBOL_GPL(napi_poll);
EXPORT_TRACEPOINT_SYMBOL_GPL(tcp_send_reset);
+EXPORT_TRACEPOINT_SYMBOL_GPL(tcp_bad_csum);
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 4cf4dd532d1c..cd52ce0a2a85 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5885,6 +5885,7 @@ step5:
return;
csum_error:
+ trace_tcp_bad_csum(skb);
TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 312184cead57..4f5b68a90be9 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1731,6 +1731,7 @@ discard:
return 0;
csum_err:
+ trace_tcp_bad_csum(skb);
TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
goto discard;
@@ -1801,6 +1802,7 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
if (unlikely(tcp_checksum_complete(skb))) {
bh_unlock_sock(sk);
+ trace_tcp_bad_csum(skb);
__TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
__TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
return true;
@@ -2098,6 +2100,7 @@ no_tcp_socket:
if (tcp_checksum_complete(skb)) {
csum_error:
+ trace_tcp_bad_csum(skb);
__TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
bad_packet:
__TCP_INC_STATS(net, TCP_MIB_INERRS);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 5f47c0b6e3de..4435fa342e7a 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1538,6 +1538,7 @@ discard:
kfree_skb(skb);
return 0;
csum_err:
+ trace_tcp_bad_csum(skb);
TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS);
TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS);
goto discard;
@@ -1754,6 +1755,7 @@ no_tcp_socket:
if (tcp_checksum_complete(skb)) {
csum_error:
+ trace_tcp_bad_csum(skb);
__TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
bad_packet:
__TCP_INC_STATS(net, TCP_MIB_INERRS);