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Commit aacd9289 authored by Alex Copot's avatar Alex Copot Committed by David S. Miller
Browse files

tcp: bind() use stronger condition for bind_conflict 



We must try harder to get unique (addr, port) pairs when
doing port autoselection for sockets with SO_REUSEADDR
option set.

We achieve this by adding a relaxation parameter to
inet_csk_bind_conflict. When 'relax' parameter is off
we return a conflict whenever the current searched
pair (addr, port) is not unique.

This tries to address the problems reported in patch:
	8d238b25
	Revert "tcp: bind() fix when many ports are bound"

Tests where ran for creating and binding(0) many sockets
on 100 IPs. The results are, on average:

	* 60000 sockets, 600 ports / IP:
		* 0.210 s, 620 (IP, port) duplicates without patch
		* 0.219 s, no duplicates with patch
	* 100000 sockets, 1000 ports / IP:
		* 0.371 s, 1720 duplicates without patch
		* 0.373 s, no duplicates with patch
	* 200000 sockets, 2000 ports / IP:
		* 0.766 s, 6900 duplicates without patch
		* 0.768 s, no duplicates with patch
	* 500000 sockets, 5000 ports / IP:
		* 2.227 s, 41500 duplicates without patch
		* 2.284 s, no duplicates with patch

Signed-off-by: default avatarAlex Copot <alex.mihai.c@gmail.com>
Signed-off-by: default avatarDaniel Baluta <dbaluta@ixiacom.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c72e1183

include/net/inet6_connection_sock.h

+1 −1
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ struct sock; 
struct sockaddr;



extern int inet6_csk_bind_conflict(const struct sock *sk,

				   const struct inet_bind_bucket *tb);

				   const struct inet_bind_bucket *tb, bool relax);



extern struct dst_entry* inet6_csk_route_req(struct sock *sk,

					     const struct request_sock *req);

include/net/inet_connection_sock.h

+2 −2
Original line number Diff line number Diff line
@@ -60,7 +60,7 @@ struct inet_connection_sock_af_ops { 
#endif

	void	    (*addr2sockaddr)(struct sock *sk, struct sockaddr *);

	int	    (*bind_conflict)(const struct sock *sk,

				     const struct inet_bind_bucket *tb);

				     const struct inet_bind_bucket *tb, bool relax);

};



/** inet_connection_sock - INET connection oriented sock
@@ -245,7 +245,7 @@ extern struct request_sock *inet_csk_search_req(const struct sock *sk, 
						const __be32 raddr,

						const __be32 laddr);

extern int inet_csk_bind_conflict(const struct sock *sk,

				  const struct inet_bind_bucket *tb);

				  const struct inet_bind_bucket *tb, bool relax);

extern int inet_csk_get_port(struct sock *sk, unsigned short snum);



extern struct dst_entry* inet_csk_route_req(struct sock *sk,

net/ipv4/inet_connection_sock.c

+14 −4
Original line number Diff line number Diff line
@@ -53,7 +53,7 @@ void inet_get_local_port_range(int *low, int *high) 
EXPORT_SYMBOL(inet_get_local_port_range);



int inet_csk_bind_conflict(const struct sock *sk,

			   const struct inet_bind_bucket *tb)

			   const struct inet_bind_bucket *tb, bool relax)

{

	struct sock *sk2;

	struct hlist_node *node;
@@ -79,6 +79,14 @@ int inet_csk_bind_conflict(const struct sock *sk, 
				    sk2_rcv_saddr == sk_rcv_saddr(sk))

					break;

			}

			if (!relax && reuse && sk2->sk_reuse &&

			    sk2->sk_state != TCP_LISTEN) {

				const __be32 sk2_rcv_saddr = sk_rcv_saddr(sk2);



				if (!sk2_rcv_saddr || !sk_rcv_saddr(sk) ||

				    sk2_rcv_saddr == sk_rcv_saddr(sk))

					break;

			}

		}

	}

	return node != NULL;
@@ -122,12 +130,13 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum) 
					    (tb->num_owners < smallest_size || smallest_size == -1)) {

						smallest_size = tb->num_owners;

						smallest_rover = rover;

						if (atomic_read(&hashinfo->bsockets) > (high - low) + 1) {

						if (atomic_read(&hashinfo->bsockets) > (high - low) + 1 &&

						    !inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) {

							snum = smallest_rover;

							goto tb_found;

						}

					}

					if (!inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb)) {

					if (!inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) {

						snum = rover;

						goto tb_found;

					}
@@ -178,12 +187,13 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum) 
			goto success;

		} else {

			ret = 1;

			if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb)) {

			if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, true)) {

				if (sk->sk_reuse && sk->sk_state != TCP_LISTEN &&

				    smallest_size != -1 && --attempts >= 0) {

					spin_unlock(&head->lock);

					goto again;

				}



				goto fail_unlock;

			}

		}

net/ipv6/inet6_connection_sock.c

+1 −1
Original line number Diff line number Diff line
@@ -28,7 +28,7 @@ 
#include <net/inet6_connection_sock.h>



int inet6_csk_bind_conflict(const struct sock *sk,

			    const struct inet_bind_bucket *tb)

			    const struct inet_bind_bucket *tb, bool relax)

{

	const struct sock *sk2;

	const struct hlist_node *node;