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authorBhaskar Dutta <bhaskie@gmail.com>2009-09-03 17:25:47 +0530
committerVlad Yasevich <vladislav.yasevich@hp.com>2009-09-04 18:21:01 -0400
commit723884339f90a9c420783135168cc1045750eb5d (patch)
treec8538602e56f2310470b0970bf121a1000313401 /net/sctp/bind_addr.c
parent8da645e101a8c20c6073efda3c7cc74eec01b87f (diff)
downloadlinux-723884339f90a9c420783135168cc1045750eb5d.tar.bz2
sctp: Sysctl configuration for IPv4 Address Scoping
This patch introduces a new sysctl option to make IPv4 Address Scoping configurable <draft-stewart-tsvwg-sctp-ipv4-00.txt>. In networking environments where DNAT rules in iptables prerouting chains convert destination IP's to link-local/private IP addresses, SCTP connections fail to establish as the INIT chunk is dropped by the kernel due to address scope match failure. For example to support overlapping IP addresses (same IP address with different vlan id) a Layer-5 application listens on link local IP's, and there is a DNAT rule that maps the destination IP to a link local IP. Such applications never get the SCTP INIT if the address-scoping draft is strictly followed. This sysctl configuration allows SCTP to function in such unconventional networking environments. Sysctl options: 0 - Disable IPv4 address scoping draft altogether 1 - Enable IPv4 address scoping (default, current behavior) 2 - Enable address scoping but allow IPv4 private addresses in init/init-ack 3 - Enable address scoping but allow IPv4 link local address in init/init-ack Signed-off-by: Bhaskar Dutta <bhaskar.dutta@globallogic.com> Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Diffstat (limited to 'net/sctp/bind_addr.c')
-rw-r--r--net/sctp/bind_addr.c21
1 files changed, 20 insertions, 1 deletions
diff --git a/net/sctp/bind_addr.c b/net/sctp/bind_addr.c
index 6d5944a745d4..13a6fba41077 100644
--- a/net/sctp/bind_addr.c
+++ b/net/sctp/bind_addr.c
@@ -510,9 +510,28 @@ int sctp_in_scope(const union sctp_addr *addr, sctp_scope_t scope)
* of requested destination address, sender and receiver
* SHOULD include all of its addresses with level greater
* than or equal to L.
+ *
+ * Address scoping can be selectively controlled via sysctl
+ * option
*/
- if (addr_scope <= scope)
+ switch (sctp_scope_policy) {
+ case SCTP_SCOPE_POLICY_DISABLE:
return 1;
+ case SCTP_SCOPE_POLICY_ENABLE:
+ if (addr_scope <= scope)
+ return 1;
+ break;
+ case SCTP_SCOPE_POLICY_PRIVATE:
+ if (addr_scope <= scope || SCTP_SCOPE_PRIVATE == addr_scope)
+ return 1;
+ break;
+ case SCTP_SCOPE_POLICY_LINK:
+ if (addr_scope <= scope || SCTP_SCOPE_LINK == addr_scope)
+ return 1;
+ break;
+ default:
+ break;
+ }
return 0;
}