From 8153a10c08f1312af563bb92532002e46d3f504a Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Thu, 3 Dec 2009 01:25:58 +0000 Subject: [PATCH] ipv4 05/05: add sysctl to accept packets with local source addresses commit 8ec1e0ebe26087bfc5c0394ada5feb5758014fc8 Author: Patrick McHardy Date: Thu Dec 3 12:16:35 2009 +0100 ipv4: add sysctl to accept packets with local source addresses Change fib_validate_source() to accept packets with a local source address when the "accept_local" sysctl is set for the incoming inet device. Combined with the previous patches, this allows to communicate between multiple local interfaces over the wire. Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.txt | 6 ++++++ include/linux/inetdevice.h | 1 + include/linux/sysctl.h | 1 + kernel/sysctl_check.c | 1 + net/ipv4/devinet.c | 1 + net/ipv4/fib_frontend.c | 11 +++++++---- 6 files changed, 17 insertions(+), 4 deletions(-) diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 989f5538b8dd..006b39dec87d 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -731,6 +731,12 @@ accept_source_route - BOOLEAN default TRUE (router) FALSE (host) +accept_local - BOOLEAN + Accept packets with local source addresses. In combination with + suitable routing, this can be used to direct packets between two + local interfaces over the wire and have them accepted properly. + default FALSE + rp_filter - INTEGER 0 - No source validation. 1 - Strict mode as defined in RFC3704 Strict Reverse Path diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h index eecfa559bfb4..699e85c01a4d 100644 --- a/include/linux/inetdevice.h +++ b/include/linux/inetdevice.h @@ -83,6 +83,7 @@ static inline void ipv4_devconf_setall(struct in_device *in_dev) #define IN_DEV_RPFILTER(in_dev) IN_DEV_MAXCONF((in_dev), RP_FILTER) #define IN_DEV_SOURCE_ROUTE(in_dev) IN_DEV_ANDCONF((in_dev), \ ACCEPT_SOURCE_ROUTE) +#define IN_DEV_ACCEPT_LOCAL(in_dev) IN_DEV_ORCONF((in_dev), ACCEPT_LOCAL) #define IN_DEV_BOOTP_RELAY(in_dev) IN_DEV_ANDCONF((in_dev), BOOTP_RELAY) #define IN_DEV_LOG_MARTIANS(in_dev) IN_DEV_ORCONF((in_dev), LOG_MARTIANS) diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 1e4743ee6831..9f047d73a216 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -490,6 +490,7 @@ enum NET_IPV4_CONF_PROMOTE_SECONDARIES=20, NET_IPV4_CONF_ARP_ACCEPT=21, NET_IPV4_CONF_ARP_NOTIFY=22, + NET_IPV4_CONF_ACCEPT_LOCAL=23, __NET_IPV4_CONF_MAX }; diff --git a/kernel/sysctl_check.c b/kernel/sysctl_check.c index b6e7aaea4604..f1d676e4b368 100644 --- a/kernel/sysctl_check.c +++ b/kernel/sysctl_check.c @@ -220,6 +220,7 @@ static const struct trans_ctl_table trans_net_ipv4_conf_vars_table[] = { { NET_IPV4_CONF_PROMOTE_SECONDARIES, "promote_secondaries" }, { NET_IPV4_CONF_ARP_ACCEPT, "arp_accept" }, { NET_IPV4_CONF_ARP_NOTIFY, "arp_notify" }, + { NET_IPV4_CONF_ACCEPT_LOCAL, "accept_local" }, {} }; diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index c100709d6ddf..e3126612fcbb 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -1468,6 +1468,7 @@ static struct devinet_sysctl_table { DEVINET_SYSCTL_RW_ENTRY(SEND_REDIRECTS, "send_redirects"), DEVINET_SYSCTL_RW_ENTRY(ACCEPT_SOURCE_ROUTE, "accept_source_route"), + DEVINET_SYSCTL_RW_ENTRY(ACCEPT_LOCAL, "accept_local"), DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP, "proxy_arp"), DEVINET_SYSCTL_RW_ENTRY(MEDIUM_ID, "medium_id"), DEVINET_SYSCTL_RW_ENTRY(BOOTP_RELAY, "bootp_relay"), diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index 3b373a8b0473..3323168ee52d 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -241,16 +241,17 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif, .iif = oif }; struct fib_result res; - int no_addr, rpf; + int no_addr, rpf, accept_local; int ret; struct net *net; - no_addr = rpf = 0; + no_addr = rpf = accept_local = 0; rcu_read_lock(); in_dev = __in_dev_get_rcu(dev); if (in_dev) { no_addr = in_dev->ifa_list == NULL; rpf = IN_DEV_RPFILTER(in_dev); + accept_local = IN_DEV_ACCEPT_LOCAL(in_dev); } rcu_read_unlock(); @@ -260,8 +261,10 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif, net = dev_net(dev); if (fib_lookup(net, &fl, &res)) goto last_resort; - if (res.type != RTN_UNICAST) - goto e_inval_res; + if (res.type != RTN_UNICAST) { + if (res.type != RTN_LOCAL || !accept_local) + goto e_inval_res; + } *spec_dst = FIB_RES_PREFSRC(res); fib_combine_itag(itag, &res); #ifdef CONFIG_IP_ROUTE_MULTIPATH -- 2.30.2