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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/sysctl.c
parent8da645e101a8c20c6073efda3c7cc74eec01b87f (diff)
downloadlwn-723884339f90a9c420783135168cc1045750eb5d.tar.gz
lwn-723884339f90a9c420783135168cc1045750eb5d.zip
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/sysctl.c')
-rw-r--r--net/sctp/sysctl.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 63eabbc71298..ab7151da120f 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -51,6 +51,7 @@ static int timer_max = 86400000; /* ms in one day */
static int int_max = INT_MAX;
static int sack_timer_min = 1;
static int sack_timer_max = 500;
+static int addr_scope_max = 3; /* check sctp_scope_policy_t in include/net/sctp/constants.h for max entries */
extern int sysctl_sctp_mem[3];
extern int sysctl_sctp_rmem[3];
@@ -272,6 +273,17 @@ static ctl_table sctp_table[] = {
.proc_handler = proc_dointvec,
.strategy = sysctl_intvec
},
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "addr_scope_policy",
+ .data = &sctp_scope_policy,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ .strategy = &sysctl_intvec,
+ .extra1 = &zero,
+ .extra2 = &addr_scope_max,
+ },
{ .ctl_name = 0 }
};