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Message-Id: <1403732693-18282-2-git-send-email-greearb@candelatech.com>
Date: Wed, 25 Jun 2014 14:44:53 -0700
From: greearb@...delatech.com
To: netdev@...r.kernel.org
Cc: Ben Greear <greearb@...delatech.com>
Subject: [PATCH v3 2/2] ipv6: Allow accepting RA from local IP addresses.
From: Ben Greear <greearb@...delatech.com>
This can be used in virtual networking applications, and
may have other uses as well. The option is disabled by
default.
A specific use case is setting up virtual routers, bridges, and
hosts on a single OS without the use of network namespaces or
virtual machines. With proper use of ip rules, routing tables,
veth interface pairs and/or other virtual interfaces,
and applications that can bind to interfaces and/or IP addresses,
it is possibly to create one or more virtual routers with multiple
hosts attached. The host interfaces can act as IPv6 systems,
with radvd running on the ports in the virtual routers. With the
option provided in this patch enabled, those hosts can now properly
obtain IPv6 addresses from the radvd.
Signed-off-by: Ben Greear <greearb@...delatech.com>
---
v3: Update commit message to describe use case, remove helper method,
tweak kernel message upon failure to accept RA.
Patch is against 3.14.8+
Documentation/networking/ip-sysctl.txt | 12 ++++++++++++
include/linux/ipv6.h | 1 +
include/uapi/linux/ipv6.h | 1 +
include/uapi/linux/sysctl.h | 1 +
kernel/sysctl_binary.c | 1 +
net/ipv6/addrconf.c | 10 ++++++++++
net/ipv6/ndisc.c | 21 +++++++++++++--------
7 files changed, 39 insertions(+), 8 deletions(-)
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index a30ecc6..0656756 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1223,6 +1223,18 @@ accept_ra_defrtr - BOOLEAN
Functional default: enabled if accept_ra is enabled.
disabled if accept_ra is disabled.
+accept_ra_from_local - BOOLEAN
+ Accept RA with source-address that is found on local machine
+ if the RA is otherwise proper and able to be accepted.
+ Default is to NOT accept these as it may be an un-intended
+ network loop.
+
+ Functional default:
+ enabled if accept_ra_from_local is enabled
+ on a specific interface.
+ disabled if accept_ra_from_local is disabled
+ on a specific interface.
+
accept_ra_pinfo - BOOLEAN
Learn Prefix Information in Router Advertisement.
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 2faef33..de635d1 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -39,6 +39,7 @@ struct ipv6_devconf {
#endif
__s32 proxy_ndp;
__s32 accept_source_route;
+ __s32 accept_ra_from_local;
#ifdef CONFIG_IPV6_OPTIMISTIC_DAD
__s32 optimistic_dad;
#endif
diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
index 593b0e3..efa2666 100644
--- a/include/uapi/linux/ipv6.h
+++ b/include/uapi/linux/ipv6.h
@@ -163,6 +163,7 @@ enum {
DEVCONF_MLDV1_UNSOLICITED_REPORT_INTERVAL,
DEVCONF_MLDV2_UNSOLICITED_REPORT_INTERVAL,
DEVCONF_SUPPRESS_FRAG_NDISC,
+ DEVCONF_ACCEPT_RA_FROM_LOCAL,
DEVCONF_MAX
};
diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h
index 7544146..ce15796 100644
--- a/include/uapi/linux/sysctl.h
+++ b/include/uapi/linux/sysctl.h
@@ -568,6 +568,7 @@ enum {
NET_IPV6_ACCEPT_RA_RT_INFO_MAX_PLEN=22,
NET_IPV6_PROXY_NDP=23,
NET_IPV6_ACCEPT_SOURCE_ROUTE=25,
+ NET_IPV6_ACCEPT_RA_FROM_LOCAL=26,
__NET_IPV6_MAX
};
diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index 6eacbcf..e10b51a 100644
--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -523,6 +523,7 @@ static const struct bin_table bin_net_ipv6_conf_var_table[] = {
{ CTL_INT, NET_IPV6_ACCEPT_RA_RT_INFO_MAX_PLEN, "accept_ra_rt_info_max_plen" },
{ CTL_INT, NET_IPV6_PROXY_NDP, "proxy_ndp" },
{ CTL_INT, NET_IPV6_ACCEPT_SOURCE_ROUTE, "accept_source_route" },
+ { CTL_INT, NET_IPV6_ACCEPT_RA_FROM_LOCAL, "accept_ra_from_local" },
{}
};
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 6c7fa08..f0b7305 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -186,6 +186,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
.max_desync_factor = MAX_DESYNC_FACTOR,
.max_addresses = IPV6_MAX_ADDRESSES,
.accept_ra_defrtr = 1,
+ .accept_ra_from_local = 0,
.accept_ra_pinfo = 1,
#ifdef CONFIG_IPV6_ROUTER_PREF
.accept_ra_rtr_pref = 1,
@@ -222,6 +223,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
.max_desync_factor = MAX_DESYNC_FACTOR,
.max_addresses = IPV6_MAX_ADDRESSES,
.accept_ra_defrtr = 1,
+ .accept_ra_from_local = 0,
.accept_ra_pinfo = 1,
#ifdef CONFIG_IPV6_ROUTER_PREF
.accept_ra_rtr_pref = 1,
@@ -4326,6 +4328,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
array[DEVCONF_FORCE_TLLAO] = cnf->force_tllao;
array[DEVCONF_NDISC_NOTIFY] = cnf->ndisc_notify;
array[DEVCONF_SUPPRESS_FRAG_NDISC] = cnf->suppress_frag_ndisc;
+ array[DEVCONF_ACCEPT_RA_FROM_LOCAL] = cnf->accept_ra_from_local;
}
static inline size_t inet6_ifla6_size(void)
@@ -5173,6 +5176,13 @@ static struct addrconf_sysctl_table
.proc_handler = proc_dointvec
},
{
+ .procname = "accept_ra_from_local",
+ .data = &ipv6_devconf.accept_ra_from_local,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
+ {
/* sentinel */
}
},
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 2fef3d5..d9473c6 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1151,11 +1151,15 @@ static void ndisc_router_discovery(struct sk_buff *skb)
goto skip_defrtr;
}
- if (ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
- NULL, 0)) {
+ /* Do not accept RA with source-addr found on local machine unless
+ * accept_ra_from_local is set to true.
+ */
+ if (!(in6_dev->cnf.accept_ra_from_local ||
+ ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
+ NULL, 0))) {
ND_PRINTK(2, info,
- "RA: %s, chk_addr failed for dev: %s\n",
- __func__, skb->dev->name);
+ "RA from local address detected on dev: %s: default router ignored\n",
+ skb->dev->name);
goto skip_defrtr;
}
@@ -1293,11 +1297,12 @@ skip_linkparms:
}
#ifdef CONFIG_IPV6_ROUTE_INFO
- if (ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
- NULL, 0)) {
+ if (!(in6_dev->cnf.accept_ra_from_local ||
+ ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
+ NULL, 0))) {
ND_PRINTK(2, info,
- "RA: %s, chk-addr (route info) is false for dev: %s\n",
- __func__, skb->dev->name);
+ "RA from local address detected on dev: %s: router info ignored.\n",
+ skb->dev->name);
goto skip_routeinfo;
}
--
1.7.11.7
--
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