Messages in this thread Patch in this message | | | From | menglong8.dong@gmail ... | Subject | [PATCH net-next v4 5/8] net: tcp: add skb drop reasons to tcp connect requesting | Date | Fri, 17 Jun 2022 18:05:11 +0800 |
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From: Menglong Dong <imagedong@tencent.com>
In order to get skb drop reasons during tcp connect requesting code path, we have to pass the pointer of the 'reason' as a new function argument of conn_request() in 'struct inet_connection_sock_af_ops'. As the return value of conn_request() can be positive or negative or 0, it's not flexible to make it return drop reasons.
As the return value of tcp_conn_request() is 0, so we can treat it as bool and make it return the skb drop reasons.
The new drop reasons 'LISTENOVERFLOWS' and 'TCP_REQQFULLDROP' are added, which are used for 'accept queue' and 'request queue' full.
Reviewed-by: Jiang Biao <benbjiang@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com> Signed-off-by: Menglong Dong <imagedong@tencent.com> Reported-by: kernel test robot <lkp@intel.com> -- v2: - fix compile error reported by kernel test rebot --- include/net/dropreason.h | 10 ++++++++++ include/net/inet_connection_sock.h | 3 ++- include/net/tcp.h | 9 +++++---- net/dccp/dccp.h | 3 ++- net/dccp/input.c | 3 ++- net/dccp/ipv4.c | 3 ++- net/dccp/ipv6.c | 5 +++-- net/ipv4/tcp_input.c | 22 ++++++++++++++-------- net/ipv4/tcp_ipv4.c | 9 ++++++--- net/ipv6/tcp_ipv6.c | 12 ++++++++---- net/mptcp/subflow.c | 8 +++++--- 11 files changed, 59 insertions(+), 28 deletions(-)
diff --git a/include/net/dropreason.h b/include/net/dropreason.h index 3c6f1e299c35..74512e60ab12 100644 --- a/include/net/dropreason.h +++ b/include/net/dropreason.h @@ -236,6 +236,16 @@ enum skb_drop_reason { * skb in its receive or send queue are all dropped */ SKB_DROP_REASON_SOCKET_DESTROYED, + /** + * @SKB_DROP_REASON_LISTENOVERFLOWS: accept queue of the listen + * socket is full, corresponding to LINUX_MIB_LISTENOVERFLOWS + */ + SKB_DROP_REASON_LISTENOVERFLOWS, + /** + * @SKB_DROP_REASON_TCP_REQQFULLDROP: request queue of the listen + * socket is full, corresponding to LINUX_MIB_TCPREQQFULLDROP + */ + SKB_DROP_REASON_TCP_REQQFULLDROP, /** * @SKB_DROP_REASON_MAX: the maximum of drop reason, which shouldn't be * used as a real 'reason' diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index 077cd730ce2f..7717c59ab3d7 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -37,7 +37,8 @@ struct inet_connection_sock_af_ops { void (*send_check)(struct sock *sk, struct sk_buff *skb); int (*rebuild_header)(struct sock *sk); void (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb); - int (*conn_request)(struct sock *sk, struct sk_buff *skb); + int (*conn_request)(struct sock *sk, struct sk_buff *skb, + enum skb_drop_reason *reason); struct sock *(*syn_recv_sock)(const struct sock *sk, struct sk_buff *skb, struct request_sock *req, struct dst_entry *dst, diff --git a/include/net/tcp.h b/include/net/tcp.h index 1e99f5c61f84..16da150150c3 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -443,7 +443,8 @@ void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb); void tcp_v4_mtu_reduced(struct sock *sk); void tcp_req_err(struct sock *sk, u32 seq, bool abort); void tcp_ld_RTO_revert(struct sock *sk, u32 seq); -int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb); +int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb, + enum skb_drop_reason *reason); struct sock *tcp_create_openreq_child(const struct sock *sk, struct request_sock *req, struct sk_buff *skb); @@ -2034,9 +2035,9 @@ void tcp4_proc_exit(void); #endif int tcp_rtx_synack(const struct sock *sk, struct request_sock *req); -int tcp_conn_request(struct request_sock_ops *rsk_ops, - const struct tcp_request_sock_ops *af_ops, - struct sock *sk, struct sk_buff *skb); +enum skb_drop_reason tcp_conn_request(struct request_sock_ops *rsk_ops, + const struct tcp_request_sock_ops *af_ops, + struct sock *sk, struct sk_buff *skb); /* TCP af-specific functions */ struct tcp_sock_af_ops { diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h index 7dfc00c9fb32..8c1241ae8449 100644 --- a/net/dccp/dccp.h +++ b/net/dccp/dccp.h @@ -255,7 +255,8 @@ void dccp_done(struct sock *sk); int dccp_reqsk_init(struct request_sock *rq, struct dccp_sock const *dp, struct sk_buff const *skb); -int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb); +int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb, + enum skb_drop_reason *reason); struct sock *dccp_create_openreq_child(const struct sock *sk, const struct request_sock *req, diff --git a/net/dccp/input.c b/net/dccp/input.c index 2cbb757a894f..e12baa56ca59 100644 --- a/net/dccp/input.c +++ b/net/dccp/input.c @@ -576,6 +576,7 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, const int old_state = sk->sk_state; bool acceptable; int queued = 0; + SKB_DR(reason); /* * Step 3: Process LISTEN state @@ -606,7 +607,7 @@ int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, */ rcu_read_lock(); local_bh_disable(); - acceptable = inet_csk(sk)->icsk_af_ops->conn_request(sk, skb) >= 0; + acceptable = inet_csk(sk)->icsk_af_ops->conn_request(sk, skb, &reason) >= 0; local_bh_enable(); rcu_read_unlock(); if (!acceptable) diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index da6e3b20cd75..b0e8fcabf93b 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -581,7 +581,8 @@ static struct request_sock_ops dccp_request_sock_ops __read_mostly = { .syn_ack_timeout = dccp_syn_ack_timeout, }; -int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb) +int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb, + enum skb_drop_reason *reason) { struct inet_request_sock *ireq; struct request_sock *req; diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c index fd44638ec16b..f01d6a05c7bf 100644 --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -314,7 +314,8 @@ static struct request_sock_ops dccp6_request_sock_ops = { .syn_ack_timeout = dccp_syn_ack_timeout, }; -static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb) +static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb, + enum skb_drop_reason *reason) { struct request_sock *req; struct dccp_request_sock *dreq; @@ -324,7 +325,7 @@ static int dccp_v6_conn_request(struct sock *sk, struct sk_buff *skb) struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); if (skb->protocol == htons(ETH_P_IP)) - return dccp_v4_conn_request(sk, skb); + return dccp_v4_conn_request(sk, skb, reason); if (!ipv6_unicast_destination(skb)) return 0; /* discard, don't send a reset here */ diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 2e2a9ece9af2..8617e7a8f841 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -6453,13 +6453,14 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb) */ rcu_read_lock(); local_bh_disable(); - acceptable = icsk->icsk_af_ops->conn_request(sk, skb) >= 0; + reason = SKB_NOT_DROPPED_YET; + acceptable = icsk->icsk_af_ops->conn_request(sk, skb, &reason) >= 0; local_bh_enable(); rcu_read_unlock(); if (!acceptable) return 1; - consume_skb(skb); + kfree_skb_reason(skb, reason); return 0; } SKB_DR_SET(reason, TCP_FLAGS); @@ -6879,9 +6880,9 @@ u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops, } EXPORT_SYMBOL_GPL(tcp_get_syncookie_mss); -int tcp_conn_request(struct request_sock_ops *rsk_ops, - const struct tcp_request_sock_ops *af_ops, - struct sock *sk, struct sk_buff *skb) +enum skb_drop_reason tcp_conn_request(struct request_sock_ops *rsk_ops, + const struct tcp_request_sock_ops *af_ops, + struct sock *sk, struct sk_buff *skb) { struct tcp_fastopen_cookie foc = { .len = -1 }; __u32 isn = TCP_SKB_CB(skb)->tcp_tw_isn; @@ -6893,6 +6894,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, bool want_cookie = false; struct dst_entry *dst; struct flowi fl; + SKB_DR(reason); /* TW buckets are converted to open requests without * limitations, they conserve resources and peer is @@ -6901,12 +6903,15 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, if ((net->ipv4.sysctl_tcp_syncookies == 2 || inet_csk_reqsk_queue_is_full(sk)) && !isn) { want_cookie = tcp_syn_flood_action(sk, rsk_ops->slab_name); - if (!want_cookie) + if (!want_cookie) { + SKB_DR_SET(reason, TCP_REQQFULLDROP); goto drop; + } } if (sk_acceptq_is_full(sk)) { NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); + SKB_DR_SET(reason, LISTENOVERFLOWS); goto drop; } @@ -6962,6 +6967,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, */ pr_drop_req(req, ntohs(tcp_hdr(skb)->source), rsk_ops->family); + SKB_DR_SET(reason, TCP_REQQFULLDROP); goto drop_and_release; } @@ -7014,7 +7020,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, } } reqsk_put(req); - return 0; + return SKB_NOT_DROPPED_YET; drop_and_release: dst_release(dst); @@ -7022,6 +7028,6 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, __reqsk_free(req); drop: tcp_listendrop(sk); - return 0; + return reason; } EXPORT_SYMBOL(tcp_conn_request); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index fe8f23b95d32..e1064273062a 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1458,17 +1458,20 @@ const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = { .send_synack = tcp_v4_send_synack, }; -int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) +int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb, + enum skb_drop_reason *reason) { /* Never answer to SYNs send to broadcast or multicast */ if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) goto drop; - return tcp_conn_request(&tcp_request_sock_ops, - &tcp_request_sock_ipv4_ops, sk, skb); + *reason = tcp_conn_request(&tcp_request_sock_ops, + &tcp_request_sock_ipv4_ops, sk, skb); + return *reason; drop: tcp_listendrop(sk); + *reason = SKB_DROP_REASON_IP_INADDRERRORS; return 0; } EXPORT_SYMBOL(tcp_v4_conn_request); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index f37dd4aa91c6..dbe356a166c5 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1148,24 +1148,28 @@ u16 tcp_v6_get_syncookie(struct sock *sk, struct ipv6hdr *iph, return mss; } -static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb) +static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb, + enum skb_drop_reason *reason) { if (skb->protocol == htons(ETH_P_IP)) - return tcp_v4_conn_request(sk, skb); + return tcp_v4_conn_request(sk, skb, reason); if (!ipv6_unicast_destination(skb)) goto drop; if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) { __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS); + *reason = SKB_DROP_REASON_IP_INADDRERRORS; return 0; } - return tcp_conn_request(&tcp6_request_sock_ops, - &tcp_request_sock_ipv6_ops, sk, skb); + *reason = tcp_conn_request(&tcp6_request_sock_ops, + &tcp_request_sock_ipv6_ops, sk, skb); + return *reason; drop: tcp_listendrop(sk); + *reason = SKB_DROP_REASON_IP_INADDRERRORS; return 0; /* don't send reset */ } diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 8841e8cd9ad8..5a1d05c3a1ef 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -532,7 +532,8 @@ static int subflow_v6_rebuild_header(struct sock *sk) struct request_sock_ops mptcp_subflow_request_sock_ops; static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops __ro_after_init; -static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb) +static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb, + enum skb_drop_reason *reason) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); @@ -556,14 +557,15 @@ static struct inet_connection_sock_af_ops subflow_v6_specific __ro_after_init; static struct inet_connection_sock_af_ops subflow_v6m_specific __ro_after_init; static struct proto tcpv6_prot_override; -static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb) +static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb, + enum skb_drop_reason *reason) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); pr_debug("subflow=%p", subflow); if (skb->protocol == htons(ETH_P_IP)) - return subflow_v4_conn_request(sk, skb); + return subflow_v4_conn_request(sk, skb, reason); if (!ipv6_unicast_destination(skb)) goto drop; -- 2.36.1
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