Commit 93a77c11 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: add tcp_inet6_sk() helper 



TCP ipv6 fast path dereferences a pointer to get to the inet6
part of a tcp socket, but given the fixed memory placement,
we can do better and avoid a possible cache line miss.

This also reduces register pressure, since we let the compiler
know about this memory placement.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f8d6ae0d

net/ipv6/tcp_ipv6.c

+26 −18
Original line number Diff line number Diff line
@@ -90,6 +90,17 @@ static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk, 
}

#endif



/* Helper returning the inet6 address from a given tcp socket.

 * It can be used in TCP stack instead of inet6_sk(sk).

 * This avoids a dereference and allow compiler optimizations.

 */

static struct ipv6_pinfo *tcp_inet6_sk(const struct sock *sk)

{

	struct tcp6_sock *tcp6 = container_of(tcp_sk(sk), struct tcp6_sock, tcp);



	return &tcp6->inet6;

}



static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)

{

	struct dst_entry *dst = skb_dst(skb);
@@ -99,7 +110,7 @@ static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) 


		sk->sk_rx_dst = dst;

		inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;

		inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);

		tcp_inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);

	}

}
@@ -138,7 +149,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr, 
	struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;

	struct inet_sock *inet = inet_sk(sk);

	struct inet_connection_sock *icsk = inet_csk(sk);

	struct ipv6_pinfo *np = inet6_sk(sk);

	struct ipv6_pinfo *np = tcp_inet6_sk(sk);

	struct tcp_sock *tp = tcp_sk(sk);

	struct in6_addr *saddr = NULL, *final_p, final;

	struct ipv6_txoptions *opt;
@@ -390,7 +401,7 @@ static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 
	if (sk->sk_state == TCP_CLOSE)

		goto out;



	if (ipv6_hdr(skb)->hop_limit < inet6_sk(sk)->min_hopcount) {

	if (ipv6_hdr(skb)->hop_limit < tcp_inet6_sk(sk)->min_hopcount) {

		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);

		goto out;

	}
@@ -405,7 +416,7 @@ static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 
		goto out;

	}



	np = inet6_sk(sk);

	np = tcp_inet6_sk(sk);



	if (type == NDISC_REDIRECT) {

		if (!sock_owned_by_user(sk)) {
@@ -478,7 +489,7 @@ static int tcp_v6_send_synack(const struct sock *sk, struct dst_entry *dst, 
			      enum tcp_synack_type synack_type)

{

	struct inet_request_sock *ireq = inet_rsk(req);

	struct ipv6_pinfo *np = inet6_sk(sk);

	struct ipv6_pinfo *np = tcp_inet6_sk(sk);

	struct ipv6_txoptions *opt;

	struct flowi6 *fl6 = &fl->u.ip6;

	struct sk_buff *skb;
@@ -737,7 +748,7 @@ static void tcp_v6_init_req(struct request_sock *req, 
{

	bool l3_slave = ipv6_l3mdev_skb(TCP_SKB_CB(skb)->header.h6.flags);

	struct inet_request_sock *ireq = inet_rsk(req);

	const struct ipv6_pinfo *np = inet6_sk(sk_listener);

	const struct ipv6_pinfo *np = tcp_inet6_sk(sk_listener);



	ireq->ir_v6_rmt_addr = ipv6_hdr(skb)->saddr;

	ireq->ir_v6_loc_addr = ipv6_hdr(skb)->daddr;
@@ -1066,9 +1077,8 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff * 
{

	struct inet_request_sock *ireq;

	struct ipv6_pinfo *newnp;

	const struct ipv6_pinfo *np = inet6_sk(sk);

	const struct ipv6_pinfo *np = tcp_inet6_sk(sk);

	struct ipv6_txoptions *opt;

	struct tcp6_sock *newtcp6sk;

	struct inet_sock *newinet;

	struct tcp_sock *newtp;

	struct sock *newsk;
@@ -1088,11 +1098,10 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff * 
		if (!newsk)

			return NULL;



		newtcp6sk = (struct tcp6_sock *)newsk;

		inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;

		inet_sk(newsk)->pinet6 = tcp_inet6_sk(newsk);



		newinet = inet_sk(newsk);

		newnp = inet6_sk(newsk);

		newnp = tcp_inet6_sk(newsk);

		newtp = tcp_sk(newsk);



		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
@@ -1156,12 +1165,11 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff * 
	ip6_dst_store(newsk, dst, NULL, NULL);

	inet6_sk_rx_dst_set(newsk, skb);



	newtcp6sk = (struct tcp6_sock *)newsk;

	inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;

	inet_sk(newsk)->pinet6 = tcp_inet6_sk(newsk);



	newtp = tcp_sk(newsk);

	newinet = inet_sk(newsk);

	newnp = inet6_sk(newsk);

	newnp = tcp_inet6_sk(newsk);



	memcpy(newnp, np, sizeof(struct ipv6_pinfo));
@@ -1276,9 +1284,9 @@ out: 
 */

static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)

{

	struct ipv6_pinfo *np = inet6_sk(sk);

	struct tcp_sock *tp;

	struct ipv6_pinfo *np = tcp_inet6_sk(sk);

	struct sk_buff *opt_skb = NULL;

	struct tcp_sock *tp;



	/* Imagine: socket is IPv6. IPv4 packet arrives,

	   goes to IPv4 receive handler and backlogged.
@@ -1524,7 +1532,7 @@ process: 
			return 0;

		}

	}

	if (hdr->hop_limit < inet6_sk(sk)->min_hopcount) {

	if (hdr->hop_limit < tcp_inet6_sk(sk)->min_hopcount) {

		__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);

		goto discard_and_relse;

	}
@@ -1669,7 +1677,7 @@ static void tcp_v6_early_demux(struct sk_buff *skb) 
			struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);



			if (dst)

				dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);

				dst = dst_check(dst, tcp_inet6_sk(sk)->rx_dst_cookie);

			if (dst &&

			    inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)

				skb_dst_set_noref(skb, dst);

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