[PATCH net-next 2/2] net: tcp: add skb drop reasons to route_req()
From: menglong8 . dong
Date: Tue Apr 26 2022 - 04:08:01 EST
From: Menglong Dong <imagedong@xxxxxxxxxxx>
Add skb drop reasons to the route_req() in struct tcp_request_sock_ops.
Following functions are involved:
tcp_v4_route_req()
tcp_v6_route_req()
subflow_v4_route_req()
subflow_v6_route_req()
And the new reason SKB_DROP_REASON_SECURITY is added, which is used when
skb is dropped by LSM.
Reviewed-by: Jiang Biao <benbjiang@xxxxxxxxxxx>
Reviewed-by: Hao Peng <flyingpeng@xxxxxxxxxxx>
Signed-off-by: Menglong Dong <imagedong@xxxxxxxxxxx>
---
include/linux/skbuff.h | 1 +
include/net/tcp.h | 3 ++-
include/trace/events/skb.h | 1 +
net/ipv4/tcp_input.c | 2 +-
net/ipv4/tcp_ipv4.c | 14 +++++++++++---
net/ipv6/tcp_ipv6.c | 14 +++++++++++---
net/mptcp/subflow.c | 10 ++++++----
7 files changed, 33 insertions(+), 12 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index f33b3636bbce..5909759e1b95 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -473,6 +473,7 @@ enum skb_drop_reason {
SKB_DROP_REASON_TCP_REQQFULLDROP, /* request queue of the listen
* socket is full
*/
+ SKB_DROP_REASON_SECURITY, /* dropped by LSM */
SKB_DROP_REASON_MAX,
};
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 679b1964d494..01f841611895 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2075,7 +2075,8 @@ struct tcp_request_sock_ops {
struct dst_entry *(*route_req)(const struct sock *sk,
struct sk_buff *skb,
struct flowi *fl,
- struct request_sock *req);
+ struct request_sock *req,
+ enum skb_drop_reason *reason);
u32 (*init_seq)(const struct sk_buff *skb);
u32 (*init_ts_off)(const struct net *net, const struct sk_buff *skb);
int (*send_synack)(const struct sock *sk, struct dst_entry *dst,
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index de6c93670437..aff57cd43e85 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -82,6 +82,7 @@
EM(SKB_DROP_REASON_PKT_TOO_BIG, PKT_TOO_BIG) \
EM(SKB_DROP_REASON_LISTENOVERFLOWS, LISTENOVERFLOWS) \
EM(SKB_DROP_REASON_TCP_REQQFULLDROP, TCP_REQQFULLDROP) \
+ EM(SKB_DROP_REASON_SECURITY, SECURITY) \
EMe(SKB_DROP_REASON_MAX, MAX)
#undef EM
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index e0bbbd624246..2c158593dc37 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -6928,7 +6928,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
/* Note: tcp_v6_init_req() might override ir_iif for link locals */
inet_rsk(req)->ir_iif = inet_request_bound_dev_if(sk, skb);
- dst = af_ops->route_req(sk, skb, &fl, req);
+ dst = af_ops->route_req(sk, skb, &fl, req, &reason);
if (!dst)
goto drop_and_free;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index b8daf49f54a5..12acf4823488 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1424,14 +1424,22 @@ static void tcp_v4_init_req(struct request_sock *req,
static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
struct sk_buff *skb,
struct flowi *fl,
- struct request_sock *req)
+ struct request_sock *req,
+ enum skb_drop_reason *reason)
{
+ struct dst_entry *dst;
+
tcp_v4_init_req(req, sk, skb);
- if (security_inet_conn_request(sk, skb, req))
+ if (security_inet_conn_request(sk, skb, req)) {
+ SKB_DR_SET(*reason, SECURITY);
return NULL;
+ }
- return inet_csk_route_req(sk, &fl->u.ip4, req);
+ dst = inet_csk_route_req(sk, &fl->u.ip4, req);
+ if (!dst)
+ SKB_DR_SET(*reason, IP_OUTNOROUTES);
+ return dst;
}
struct request_sock_ops tcp_request_sock_ops __read_mostly = {
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 782df529ff69..d69fef0e0892 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -802,14 +802,22 @@ static void tcp_v6_init_req(struct request_sock *req,
static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
struct sk_buff *skb,
struct flowi *fl,
- struct request_sock *req)
+ struct request_sock *req,
+ enum skb_drop_reason *reason)
{
+ struct dst_entry *dst;
+
tcp_v6_init_req(req, sk, skb);
- if (security_inet_conn_request(sk, skb, req))
+ if (security_inet_conn_request(sk, skb, req)) {
+ SKB_DR_SET(*reason, SECURITY);
return NULL;
+ }
- return inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
+ dst = inet6_csk_route_req(sk, &fl->u.ip6, req, IPPROTO_TCP);
+ if (!dst)
+ SKB_DR_SET(*reason, IP_OUTNOROUTES);
+ return dst;
}
struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index aba260f547da..03d07165cda6 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -283,7 +283,8 @@ EXPORT_SYMBOL_GPL(mptcp_subflow_init_cookie_req);
static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
struct sk_buff *skb,
struct flowi *fl,
- struct request_sock *req)
+ struct request_sock *req,
+ enum skb_drop_reason *reason)
{
struct dst_entry *dst;
int err;
@@ -291,7 +292,7 @@ static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
tcp_rsk(req)->is_mptcp = 1;
subflow_init_req(req, sk);
- dst = tcp_request_sock_ipv4_ops.route_req(sk, skb, fl, req);
+ dst = tcp_request_sock_ipv4_ops.route_req(sk, skb, fl, req, reason);
if (!dst)
return NULL;
@@ -309,7 +310,8 @@ static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
static struct dst_entry *subflow_v6_route_req(const struct sock *sk,
struct sk_buff *skb,
struct flowi *fl,
- struct request_sock *req)
+ struct request_sock *req,
+ enum skb_drop_reason *reason)
{
struct dst_entry *dst;
int err;
@@ -317,7 +319,7 @@ static struct dst_entry *subflow_v6_route_req(const struct sock *sk,
tcp_rsk(req)->is_mptcp = 1;
subflow_init_req(req, sk);
- dst = tcp_request_sock_ipv6_ops.route_req(sk, skb, fl, req);
+ dst = tcp_request_sock_ipv6_ops.route_req(sk, skb, fl, req, reason);
if (!dst)
return NULL;
--
2.36.0