Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757898Ab0DIKLr (ORCPT ); Fri, 9 Apr 2010 06:11:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46204 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757833Ab0DIKLl (ORCPT ); Fri, 9 Apr 2010 06:11:41 -0400 Date: Fri, 9 Apr 2010 06:11:24 -0400 From: Amerigo Wang To: linux-kernel@vger.kernel.org Cc: Octavian Purdila , Eric Dumazet , netdev@vger.kernel.org, Neil Horman , Amerigo Wang , David Miller , ebiederm@xmission.com Message-Id: <20100409101513.5051.97926.sendpatchset@localhost.localdomain> In-Reply-To: <20100409101442.5051.99812.sendpatchset@localhost.localdomain> References: <20100409101442.5051.99812.sendpatchset@localhost.localdomain> Subject: [Patch 3/3] net: reserve ports for applications using fixed port numbers Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8278 Lines: 242 From: Octavian Purdila This patch introduces /proc/sys/net/ipv4/ip_local_reserved_ports which allows users to reserve ports for third-party applications. The reserved ports will not be used by automatic port assignments (e.g. when calling connect() or bind() with port number 0). Explicit port allocation behavior is unchanged. Signed-off-by: Octavian Purdila Signed-off-by: WANG Cong Cc: Neil Horman Cc: Eric Dumazet Cc: Eric W. Biederman --- Index: linux-2.6/Documentation/networking/ip-sysctl.txt =================================================================== --- linux-2.6.orig/Documentation/networking/ip-sysctl.txt +++ linux-2.6/Documentation/networking/ip-sysctl.txt @@ -588,6 +588,37 @@ ip_local_port_range - 2 INTEGERS (i.e. by default) range 1024-4999 is enough to issue up to 2000 connections per second to systems supporting timestamps. +ip_local_reserved_ports - list of comma separated ranges + Specify the ports which are reserved for known third-party + applications. These ports will not be used by automatic port + assignments (e.g. when calling connect() or bind() with port + number 0). Explicit port allocation behavior is unchanged. + + The format used for both input and output is a comma separated + list of ranges (e.g. "1,2-4,10-10" for ports 1, 2, 3, 4 and + 10). Writing to the file will clear all previously reserved + ports and update the current list with the one given in the + input. + + Note that ip_local_port_range and ip_local_reserved_ports + settings are independent and both are considered by the kernel + when determining which ports are available for automatic port + assignments. + + You can reserve ports which are not in the current + ip_local_port_range, e.g.: + + $ cat /proc/sys/net/ipv4/ip_local_port_range + 32000 61000 + $ cat /proc/sys/net/ipv4/ip_local_reserved_ports + 8080,9148 + + although this is redundant. However such a setting is useful + if later the port range is changed to a value that will + include the reserved ports. + + Default: Empty + ip_nonlocal_bind - BOOLEAN If set, allows processes to bind() to non-local IP addresses, which can be quite useful - but may break some applications. Index: linux-2.6/drivers/infiniband/core/cma.c =================================================================== --- linux-2.6.orig/drivers/infiniband/core/cma.c +++ linux-2.6/drivers/infiniband/core/cma.c @@ -1980,6 +1980,8 @@ retry: /* FIXME: add proper port randomization per like inet_csk_get_port */ do { ret = idr_get_new_above(ps, bind_list, next_port, &port); + if (inet_is_reserved_local_port(port)) + ret = -EAGAIN; } while ((ret == -EAGAIN) && idr_pre_get(ps, GFP_KERNEL)); if (ret) @@ -2996,10 +2998,13 @@ static int __init cma_init(void) { int ret, low, high, remaining; - get_random_bytes(&next_port, sizeof next_port); inet_get_local_port_range(&low, &high); +again: + get_random_bytes(&next_port, sizeof next_port); remaining = (high - low) + 1; next_port = ((unsigned int) next_port % remaining) + low; + if (inet_is_reserved_local_port(next_port)) + goto again; cma_wq = create_singlethread_workqueue("rdma_cm"); if (!cma_wq) Index: linux-2.6/include/net/ip.h =================================================================== --- linux-2.6.orig/include/net/ip.h +++ linux-2.6/include/net/ip.h @@ -184,6 +184,12 @@ extern struct local_ports { } sysctl_local_ports; extern void inet_get_local_port_range(int *low, int *high); +extern unsigned long *sysctl_local_reserved_ports; +static inline int inet_is_reserved_local_port(int port) +{ + return test_bit(port, sysctl_local_reserved_ports); +} + extern int sysctl_ip_default_ttl; extern int sysctl_ip_nonlocal_bind; Index: linux-2.6/net/ipv4/af_inet.c =================================================================== --- linux-2.6.orig/net/ipv4/af_inet.c +++ linux-2.6/net/ipv4/af_inet.c @@ -1552,9 +1552,13 @@ static int __init inet_init(void) BUILD_BUG_ON(sizeof(struct inet_skb_parm) > sizeof(dummy_skb->cb)); + sysctl_local_reserved_ports = kzalloc(65536 / 8, GFP_KERNEL); + if (!sysctl_local_reserved_ports) + goto out; + rc = proto_register(&tcp_prot, 1); if (rc) - goto out; + goto out_free_reserved_ports; rc = proto_register(&udp_prot, 1); if (rc) @@ -1653,6 +1657,8 @@ out_unregister_udp_proto: proto_unregister(&udp_prot); out_unregister_tcp_proto: proto_unregister(&tcp_prot); +out_free_reserved_ports: + kfree(sysctl_local_reserved_ports); goto out; } Index: linux-2.6/net/ipv4/inet_connection_sock.c =================================================================== --- linux-2.6.orig/net/ipv4/inet_connection_sock.c +++ linux-2.6/net/ipv4/inet_connection_sock.c @@ -37,6 +37,9 @@ struct local_ports sysctl_local_ports __ .range = { 32768, 61000 }, }; +unsigned long *sysctl_local_reserved_ports; +EXPORT_SYMBOL(sysctl_local_reserved_ports); + void inet_get_local_port_range(int *low, int *high) { unsigned seq; @@ -108,6 +111,8 @@ again: smallest_size = -1; do { + if (inet_is_reserved_local_port(rover)) + goto next_nolock; head = &hashinfo->bhash[inet_bhashfn(net, rover, hashinfo->bhash_size)]; spin_lock(&head->lock); @@ -130,6 +135,7 @@ again: break; next: spin_unlock(&head->lock); + next_nolock: if (++rover > high) rover = low; } while (--remaining > 0); Index: linux-2.6/net/ipv4/inet_hashtables.c =================================================================== --- linux-2.6.orig/net/ipv4/inet_hashtables.c +++ linux-2.6/net/ipv4/inet_hashtables.c @@ -456,6 +456,8 @@ int __inet_hash_connect(struct inet_time local_bh_disable(); for (i = 1; i <= remaining; i++) { port = low + (i + offset) % remaining; + if (inet_is_reserved_local_port(port)) + continue; head = &hinfo->bhash[inet_bhashfn(net, port, hinfo->bhash_size)]; spin_lock(&head->lock); Index: linux-2.6/net/ipv4/sysctl_net_ipv4.c =================================================================== --- linux-2.6.orig/net/ipv4/sysctl_net_ipv4.c +++ linux-2.6/net/ipv4/sysctl_net_ipv4.c @@ -299,6 +299,13 @@ static struct ctl_table ipv4_table[] = { .mode = 0644, .proc_handler = ipv4_local_port_range, }, + { + .procname = "ip_local_reserved_ports", + .data = NULL, /* initialized in sysctl_ipv4_init */ + .maxlen = 65536, + .mode = 0644, + .proc_handler = proc_do_large_bitmap, + }, #ifdef CONFIG_IP_MULTICAST { .procname = "igmp_max_memberships", @@ -736,6 +743,16 @@ static __net_initdata struct pernet_oper static __init int sysctl_ipv4_init(void) { struct ctl_table_header *hdr; + struct ctl_table *i; + + for (i = ipv4_table; i->procname; i++) { + if (strcmp(i->procname, "ip_local_reserved_ports") == 0) { + i->data = sysctl_local_reserved_ports; + break; + } + } + if (!i->procname) + return -EINVAL; hdr = register_sysctl_paths(net_ipv4_ctl_path, ipv4_table); if (hdr == NULL) Index: linux-2.6/net/ipv4/udp.c =================================================================== --- linux-2.6.orig/net/ipv4/udp.c +++ linux-2.6/net/ipv4/udp.c @@ -233,7 +233,8 @@ int udp_lib_get_port(struct sock *sk, un */ do { if (low <= snum && snum <= high && - !test_bit(snum >> udptable->log, bitmap)) + !test_bit(snum >> udptable->log, bitmap) && + !inet_is_reserved_local_port(snum)) goto found; snum += rand; } while (snum != first); Index: linux-2.6/net/sctp/socket.c =================================================================== --- linux-2.6.orig/net/sctp/socket.c +++ linux-2.6/net/sctp/socket.c @@ -5436,6 +5436,8 @@ static long sctp_get_port_local(struct s rover++; if ((rover < low) || (rover > high)) rover = low; + if (inet_is_reserved_local_port(rover)) + continue; index = sctp_phashfn(rover); head = &sctp_port_hashtable[index]; sctp_spin_lock(&head->lock); 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