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.
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| @@ -168,6 +168,7 @@ enum · 167 unmodified lines | |||
| 168 | IPV4_DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN, | 168 | IPV4_DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN, |
| 169 | IPV4_DEVCONF_DROP_UNICAST_IN_L2_MULTICAST, | 169 | IPV4_DEVCONF_DROP_UNICAST_IN_L2_MULTICAST, |
| 170 | IPV4_DEVCONF_DROP_GRATUITOUS_ARP, | 170 | IPV4_DEVCONF_DROP_GRATUITOUS_ARP, |
| 171 | IPV4_DEVCONF_BC_FORWARDING, | ||
| 171 | __IPV4_DEVCONF_MAX | 172 | __IPV4_DEVCONF_MAX |
| 172 | }; | 173 | }; |
| 173 | 174 | ||
| @@ -18,6 +18,7 @@ enum { · 17 unmodified lines | |||
| 18 | NETCONFA_PROXY_NEIGH, | 18 | NETCONFA_PROXY_NEIGH, |
| 19 | NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN, | 19 | NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN, |
| 20 | NETCONFA_INPUT, | 20 | NETCONFA_INPUT, |
| 21 | NETCONFA_BC_FORWARDING, | ||
| 21 | __NETCONFA_MAX | 22 | __NETCONFA_MAX |
| 22 | }; | 23 | }; |
| 23 | #define NETCONFA_MAX (__NETCONFA_MAX - 1) | 24 | #define NETCONFA_MAX (__NETCONFA_MAX - 1) |