tcp_comp: add stub proto ops for tcp compression socket

hulk inclusion
category: feature
bugzilla: NA
CVE: NA

-------------------------------------------------

Add stub proto ops for tcp compression socket.
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NWang Yufen <wangyufen@huawei.com>
Reviewed-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

include/net/tcp.h

@@ -2221,6 +2221,7 @@ bool tcp_synack_comp_enabled(const struct sock *sk,
 			     const struct inet_request_sock *ireq);
 void tcp_init_compression(struct sock *sk);
 void tcp_cleanup_compression(struct sock *sk);
+int tcp_comp_init(void);
 #else
 static inline bool tcp_syn_comp_enabled(const struct tcp_sock *tp)
 {
@@ -2240,6 +2241,11 @@ static inline void tcp_init_compression(struct sock *sk)
 static inline void tcp_cleanup_compression(struct sock *sk)
 {
 }
+
+static inline int tcp_comp_init(void)
+{
+	return 0;
+}
 #endif
 
 #endif	/* _TCP_H */

net/ipv4/tcp.c

@@ -3959,4 +3959,5 @@ void __init tcp_init(void)
 	tcp_metrics_init();
 	BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
 	tcp_tasklet_init();
+	tcp_comp_init();
 }

net/ipv4/tcp_comp.c

@@ -12,6 +12,13 @@ static unsigned long tcp_compression_ports[65536 / 8];
 unsigned long *sysctl_tcp_compression_ports = tcp_compression_ports;
 int sysctl_tcp_compression_local __read_mostly;
 
+static struct proto tcp_prot_override;
+
+struct tcp_comp_context {
+	struct proto *sk_proto;
+	struct rcu_head rcu;
+};
+
 static bool tcp_comp_enabled(__be32 saddr, __be32 daddr, int port)
 {
 	if (!sysctl_tcp_compression_local &&
@@ -41,16 +48,75 @@ bool tcp_synack_comp_enabled(const struct sock *sk,
 				ntohs(inet->inet_sport));
 }
 
+static struct tcp_comp_context *comp_get_ctx(const struct sock *sk)
+{
+	struct inet_connection_sock *icsk = inet_csk(sk);
+
+	return (__force void *)icsk->icsk_ulp_data;
+}
+
+static int tcp_comp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
+{
+	struct tcp_comp_context *ctx = comp_get_ctx(sk);
+
+	return ctx->sk_proto->sendmsg(sk, msg, size);
+}
+
+static int tcp_comp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
+			    int nonblock, int flags, int *addr_len)
+{
+	struct tcp_comp_context *ctx = comp_get_ctx(sk);
+
+	return ctx->sk_proto->recvmsg(sk, msg, len, nonblock, flags, addr_len);
+}
+
 void tcp_init_compression(struct sock *sk)
 {
+	struct inet_connection_sock *icsk = inet_csk(sk);
+	struct tcp_comp_context *ctx = NULL;
 	struct tcp_sock *tp = tcp_sk(sk);
 
 	if (!tp->rx_opt.smc_ok)
 		return;
 
+	ctx = kzalloc(sizeof(*ctx), GFP_ATOMIC);
+	if (!ctx)
+		return;
+
+	ctx->sk_proto = sk->sk_prot;
+	WRITE_ONCE(sk->sk_prot, &tcp_prot_override);
+
+	rcu_assign_pointer(icsk->icsk_ulp_data, ctx);
+
 	sock_set_flag(sk, SOCK_COMP);
 }
 
+static void tcp_comp_context_free(struct rcu_head *head)
+{
+	struct tcp_comp_context *ctx;
+
+	ctx = container_of(head, struct tcp_comp_context, rcu);
+
+	kfree(ctx);
+}
+
 void tcp_cleanup_compression(struct sock *sk)
 {
+	struct inet_connection_sock *icsk = inet_csk(sk);
+	struct tcp_comp_context *ctx = comp_get_ctx(sk);
+
+	if (!ctx || !sock_flag(sk, SOCK_COMP))
+		return;
+
+	rcu_assign_pointer(icsk->icsk_ulp_data, NULL);
+	call_rcu(&ctx->rcu, tcp_comp_context_free);
+}
+
+int tcp_comp_init(void)
+{
+	tcp_prot_override = tcp_prot;
+	tcp_prot_override.sendmsg = tcp_comp_sendmsg;
+	tcp_prot_override.recvmsg = tcp_comp_recvmsg;
+
+	return 0;
 }