From: Menglong Dong <imagedong@xxxxxxxxxxx>
Pass the address of drop reason to tcp_v4_inbound_md5_hash() and
tcp_v6_inbound_md5_hash() to store the reasons for skb drops when this
function fails. Therefore, the drop reason can be passed to
kfree_skb_reason() when the skb needs to be freed.
Following drop reasons are added:
SKB_DROP_REASON_TCP_MD5NOTFOUND
SKB_DROP_REASON_TCP_MD5UNEXPECTED
SKB_DROP_REASON_TCP_MD5FAILURE
SKB_DROP_REASON_TCP_MD5* above correspond to LINUX_MIB_TCPMD5*
Signed-off-by: Menglong Dong <imagedong@xxxxxxxxxxx>
---
include/linux/skbuff.h | 12 ++++++++++++
include/trace/events/skb.h | 4 ++++
net/ipv4/tcp_ipv4.c | 13 +++++++++----
net/ipv6/tcp_ipv6.c | 11 ++++++++---
4 files changed, 33 insertions(+), 7 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index a5adbf6b51e8..46678eb587ff 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -346,6 +346,18 @@ enum skb_drop_reason {
* udp packet drop out of
* udp_memory_allocated.
*/
+ SKB_DROP_REASON_TCP_MD5NOTFOUND, /* no MD5 hash and one
+ * expected, corresponding
+ * to LINUX_MIB_TCPMD5NOTFOUND
+ */
+ SKB_DROP_REASON_TCP_MD5UNEXPECTED, /* MD5 hash and we're not
+ * expecting one, corresponding
+ * to LINUX_MIB_TCPMD5UNEXPECTED
+ */
+ SKB_DROP_REASON_TCP_MD5FAILURE, /* MD5 hash and its wrong,
+ * corresponding to
+ * LINUX_MIB_TCPMD5FAILURE
+ */
SKB_DROP_REASON_MAX,
};
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index cfcfd26399f7..46c06b0be850 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -27,6 +27,10 @@
EM(SKB_DROP_REASON_IP_NOPROTO, IP_NOPROTO) \
EM(SKB_DROP_REASON_SOCKET_RCVBUFF, SOCKET_RCVBUFF) \
EM(SKB_DROP_REASON_PROTO_MEM, PROTO_MEM) \
+ EM(SKB_DROP_REASON_TCP_MD5NOTFOUND, TCP_MD5NOTFOUND) \
+ EM(SKB_DROP_REASON_TCP_MD5UNEXPECTED, \
+ TCP_MD5UNEXPECTED) \
+ EM(SKB_DROP_REASON_TCP_MD5FAILURE, TCP_MD5FAILURE) \
EMe(SKB_DROP_REASON_MAX, MAX)
#undef EM
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index a3beab01e9a7..d3c417119057 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1412,7 +1412,8 @@ EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
/* Called with rcu_read_lock() */
static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
const struct sk_buff *skb,
- int dif, int sdif)
+ int dif, int sdif,
+ enum skb_drop_reason *reason)
{
#ifdef CONFIG_TCP_MD5SIG
/*
@@ -1445,11 +1446,13 @@ static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
return false;
if (hash_expected && !hash_location) {
+ *reason = SKB_DROP_REASON_TCP_MD5NOTFOUND;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
return true;
}
if (!hash_expected && hash_location) {
+ *reason = SKB_DROP_REASON_TCP_MD5UNEXPECTED;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
return true;
}
@@ -1462,6 +1465,7 @@ static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
NULL, skb);
if (genhash || memcmp(hash_location, newhash, 16) != 0) {
+ *reason = SKB_DROP_REASON_TCP_MD5FAILURE;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s L3 index %d\n",
&iph->saddr, ntohs(th->source),
@@ -1971,13 +1975,13 @@ static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
int tcp_v4_rcv(struct sk_buff *skb)
{
struct net *net = dev_net(skb->dev);
+ enum skb_drop_reason drop_reason;
int sdif = inet_sdif(skb);
int dif = inet_iif(skb);
const struct iphdr *iph;
const struct tcphdr *th;
bool refcounted;
struct sock *sk;
- int drop_reason;
int ret;
drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
@@ -2025,7 +2029,8 @@ int tcp_v4_rcv(struct sk_buff *skb)
struct sock *nsk;
sk = req->rsk_listener;
- if (unlikely(tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))) {
+ if (unlikely(tcp_v4_inbound_md5_hash(sk, skb, dif, sdif,
+ &drop_reason))) {
sk_drops_add(sk, skb);
reqsk_put(req);
goto discard_it;
@@ -2099,7 +2104,7 @@ int tcp_v4_rcv(struct sk_buff *skb)
goto discard_and_relse;
}
- if (tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))
+ if (tcp_v4_inbound_md5_hash(sk, skb, dif, sdif, &drop_reason))
goto discard_and_relse;
nf_reset_ct(skb);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 0aa17073df1a..1262b790b146 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -775,7 +775,8 @@ static int tcp_v6_md5_hash_skb(char *md5_hash,
static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
const struct sk_buff *skb,
- int dif, int sdif)
+ int dif, int sdif,
+ enum skb_drop_reason *reason)
{
#ifdef CONFIG_TCP_MD5SIG
const __u8 *hash_location = NULL;
@@ -798,11 +799,13 @@ static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
return false;
if (hash_expected && !hash_location) {
+ *reason = SKB_DROP_REASON_TCP_MD5NOTFOUND;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
return true;
}
if (!hash_expected && hash_location) {
+ *reason = SKB_DROP_REASON_TCP_MD5UNEXPECTED;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
return true;
}
@@ -813,6 +816,7 @@ static bool tcp_v6_inbound_md5_hash(const struct sock *sk,
NULL, skb);
if (genhash || memcmp(hash_location, newhash, 16) != 0) {
+ *reason = SKB_DROP_REASON_TCP_MD5FAILURE;
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE);
net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u L3 index %d\n",
genhash ? "failed" : "mismatch",
@@ -1681,7 +1685,8 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
struct sock *nsk;
sk = req->rsk_listener;
- if (tcp_v6_inbound_md5_hash(sk, skb, dif, sdif)) {
+ if (tcp_v6_inbound_md5_hash(sk, skb, dif, sdif,
+ &drop_reason)) {
sk_drops_add(sk, skb);
reqsk_put(req);
goto discard_it;
@@ -1752,7 +1757,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
goto discard_and_relse;
}
- if (tcp_v6_inbound_md5_hash(sk, skb, dif, sdif))
+ if (tcp_v6_inbound_md5_hash(sk, skb, dif, sdif, &drop_reason))
goto discard_and_relse;
if (tcp_filter(sk, skb)) {
--
2.34.1
