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authorXin Long <lucien.xin@gmail.com>2018-07-27 16:37:28 +0800
committerDavid S. Miller <davem@davemloft.net>2018-07-29 12:37:06 -0700
commit5cbf777cfdf6e5a7b7149006e4881a255da78fdd (patch)
treeae012b8fd609fdc7768819f156aa397a12611619 /net/ipv4
parentnet/ipv6: allow any source address for sendmsg pktinfo with ip_nonlocal_bind (diff)
downloadlinux-dev-5cbf777cfdf6e5a7b7149006e4881a255da78fdd.tar.xz
linux-dev-5cbf777cfdf6e5a7b7149006e4881a255da78fdd.zip
route: add support for directed broadcast forwarding
This patch implements the feature described in rfc1812#section-5.3.5.2 and rfc2644. It allows the router to forward directed broadcast when sysctl bc_forwarding is enabled. Note that this feature could be done by iptables -j TEE, but it would cause some problems: - target TEE's gateway param has to be set with a specific address, and it's not flexible especially when the route wants forward all directed broadcasts. - this duplicates the directed broadcasts so this may cause side effects to applications. Besides, to keep consistent with other os router like BSD, it's also necessary to implement it in the route rx path. Note that route cache needs to be flushed when bc_forwarding is changed. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/devinet.c11
-rw-r--r--net/ipv4/route.c6
2 files changed, 16 insertions, 1 deletions
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index d7585ab1a77a..ea4bd8a52422 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1827,6 +1827,8 @@ static int inet_netconf_msgsize_devconf(int type)
size += nla_total_size(4);
if (all || type == NETCONFA_MC_FORWARDING)
size += nla_total_size(4);
+ if (all || type == NETCONFA_BC_FORWARDING)
+ size += nla_total_size(4);
if (all || type == NETCONFA_PROXY_NEIGH)
size += nla_total_size(4);
if (all || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN)
@@ -1873,6 +1875,10 @@ static int inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
nla_put_s32(skb, NETCONFA_MC_FORWARDING,
IPV4_DEVCONF(*devconf, MC_FORWARDING)) < 0)
goto nla_put_failure;
+ if ((all || type == NETCONFA_BC_FORWARDING) &&
+ nla_put_s32(skb, NETCONFA_BC_FORWARDING,
+ IPV4_DEVCONF(*devconf, BC_FORWARDING)) < 0)
+ goto nla_put_failure;
if ((all || type == NETCONFA_PROXY_NEIGH) &&
nla_put_s32(skb, NETCONFA_PROXY_NEIGH,
IPV4_DEVCONF(*devconf, PROXY_ARP)) < 0)
@@ -2143,6 +2149,10 @@ static int devinet_conf_proc(struct ctl_table *ctl, int write,
if ((new_value == 0) && (old_value != 0))
rt_cache_flush(net);
+ if (i == IPV4_DEVCONF_BC_FORWARDING - 1 &&
+ new_value != old_value)
+ rt_cache_flush(net);
+
if (i == IPV4_DEVCONF_RP_FILTER - 1 &&
new_value != old_value) {
ifindex = devinet_conf_ifindex(net, cnf);
@@ -2259,6 +2269,7 @@ static struct devinet_sysctl_table {
DEVINET_SYSCTL_COMPLEX_ENTRY(FORWARDING, "forwarding",
devinet_sysctl_forward),
DEVINET_SYSCTL_RO_ENTRY(MC_FORWARDING, "mc_forwarding"),
+ DEVINET_SYSCTL_RW_ENTRY(BC_FORWARDING, "bc_forwarding"),
DEVINET_SYSCTL_RW_ENTRY(ACCEPT_REDIRECTS, "accept_redirects"),
DEVINET_SYSCTL_RW_ENTRY(SECURE_REDIRECTS, "secure_redirects"),
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 1df6e97106d7..b678466da451 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1996,8 +1996,11 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
goto no_route;
}
- if (res->type == RTN_BROADCAST)
+ if (res->type == RTN_BROADCAST) {
+ if (IN_DEV_BFORWARD(in_dev))
+ goto make_route;
goto brd_input;
+ }
if (res->type == RTN_LOCAL) {
err = fib_validate_source(skb, saddr, daddr, tos,
@@ -2014,6 +2017,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
if (res->type != RTN_UNICAST)
goto martian_destination;
+make_route:
err = ip_mkroute_input(skb, res, in_dev, daddr, saddr, tos, flkeys);
out: return err;