A new RTF_CACHE route can be created with the socket's dst cache
update between the below calls in udpv6_sendmsg(), when datagram
sending results to ICMPV6_PKT_TOOBIG error:
dst = ip6_sk_dst_lookup_flow(...)
...
release_dst:
if (dst) {
if (connected) {
ip6_dst_store(sk, dst)
Therefore, the new socket's dst cache reset to the old one on
"release_dst:".
The first two patches prepare the code to store dst cache
with ip6_sk_dst_lookup_flow():
* the first patch adds ip6_sk_dst_store_flow() function with
commonly used source and destiantion addresses checks using
the flow information.
* the second patch adds new argument to ip6_sk_dst_lookup_flow()
and ability to store dst in the socket's cache. Also, the two
users of the function are updated without enabling the new
behavior: pingv6_sendmsg() and udpv6_sendmsg().
The last patch contains the actual fix that removes sk dst cache
update in the end of udpv6_sendmsg(), and allows to do it in
ip6_sk_dst_lookup_flow().
v5: * relocate ip6_sk_dst_store_flow() to net/ipv6/route.c and
rename ip6_dst_store_flow() to ip6_sk_dst_store_flow() as
suggested by Martin
v4: * fix the error in the build of ip_dst_store_flow() reported by
kbuild test robot due to missing checks for CONFIG_IPV6: add
new function to ip6_output.c instead of ip6_route.h
* add 'const' to struct flowi6 in ip6_dst_store_flow()
* minor commit messages fixes
v3: * instead of moving ip6_dst_store() above udp_v6_send_skb(),
update socket's dst cache inside ip6_sk_dst_lookup_flow()
if the current one is invalid
* the issue not reproduced in 4.1, but starting from 4.2. Add
one more 'Fixes:' commit that creates new RTF_CACHE route.
Though, it is also mentioned in the first one
Alexey Kodanev (3):
ipv6: add a wrapper for ip6_dst_store() with flowi6 checks
ipv6: allow to cache dst for a connected sk in ip6_sk_dst_lookup_flow()
ipv6: udp6: set dst cache for a connected sk if current not valid
include/net/ip6_route.h | 3 +++
include/net/ipv6.h | 3 ++-
net/ipv6/datagram.c | 9 +--------
net/ipv6/ip6_output.c | 15 ++++++++++++---
net/ipv6/ping.c | 2 +-
net/ipv6/route.c | 17 +++++++++++++++++
net/ipv6/udp.c | 21 ++-------------------
7 files changed, 38 insertions(+), 32 deletions(-)
--
1.8.3.1
