diff mbox series

[v4,2/2] ip/ip6_gre: Fix non-point-to-point tunnel not generating IPv6 link local address

Message ID 20230127025941.2813766-3-Thomas.Winter@alliedtelesis.co.nz (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series ip/ip6_gre: Fix GRE tunnels not generating IPv6 link local addresses | expand

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netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: line length of 85 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Thomas Winter Jan. 27, 2023, 2:59 a.m. UTC
We recently found that our non-point-to-point tunnels were not
generating any IPv6 link local address and instead generating an
IPv6 compat address, breaking IPv6 communication on the tunnel.

Previously, addrconf_gre_config always would call addrconf_addr_gen
and generate a EUI64 link local address for the tunnel.
Then commit e5dd729460ca changed the code path so that add_v4_addrs
is called but this only generates a compat IPv6 address for
non-point-to-point tunnels.

I assume the compat address is specifically for SIT tunnels so
have kept that only for SIT - GRE tunnels now always generate link
local addresses.

Fixes: e5dd729460ca ("ip/ip6_gre: use the same logic as SIT interfaces when computing v6LL address")
Signed-off-by: Thomas Winter <Thomas.Winter@alliedtelesis.co.nz>
---
 net/ipv6/addrconf.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 0065b38fc85b..a45d7544d6a6 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3127,17 +3127,17 @@  static void add_v4_addrs(struct inet6_dev *idev)
 		offset = sizeof(struct in6_addr) - 4;
 	memcpy(&addr.s6_addr32[3], idev->dev->dev_addr + offset, 4);
 
-	if (idev->dev->flags&IFF_POINTOPOINT) {
+	if (!(idev->dev->flags & IFF_POINTOPOINT) && idev->dev->type == ARPHRD_SIT) {
+		scope = IPV6_ADDR_COMPATv4;
+		plen = 96;
+		pflags |= RTF_NONEXTHOP;
+	} else {
 		if (idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_NONE)
 			return;
 
 		addr.s6_addr32[0] = htonl(0xfe800000);
 		scope = IFA_LINK;
 		plen = 64;
-	} else {
-		scope = IPV6_ADDR_COMPATv4;
-		plen = 96;
-		pflags |= RTF_NONEXTHOP;
 	}
 
 	if (addr.s6_addr32[3]) {